Thesis (MSc Food Sc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The sensory characteristics and chemical composition of rooibos infusions were analysed to establish the extent of variation in sensory attributes and compositional parameters, and investigate whether correlations exist between the sensory characteristics and the phenolic composition. To capture as much potential variation as possible, 69 rooibos samples were collected throughout the 2009 harvesting season from different production areas. The samples were also representative of the different quality grades (A, B, C or D) which are based on the appearance of the leaves, and the colour and flavour of the infusion. Quantitative descriptive analysis was used to develop sensory profiles for each of the rooibos infusions. Considerable variation in the sensory characteristics was observed, highlighting the need for standardised terminology that can be used to describe what is often referred to as “characteristic” rooibos flavour. Aroma, flavour, taste, and mouthfeel descriptors were generated and assembled into a rooibos sensory wheel. The most recurring attributes were selected to compile a rooibos sensory lexicon which provides a definition and a reference standard for clarification of each term. A combination of “honey”, “woody” and “fynbos-floral” notes with a slightly sweet taste and subtle astringency may be regarded as “characteristic” rooibos attributes indicative of good quality tea. Pleasant “caramel” and “fruity-sweet” notes were also observed in a number of infusions, whereas negative descriptors, associated with poor quality rooibos, included “green” and “hay” flavours. Large variation in the composition of rooibos infusions was revealed through the quantification of soluble solids (SS), total polyphenols (TP), tannins and 14 monomeric phenolic compounds, as well as spectrophotometric colour measurements. High quality rooibos was associated with higher levels of SS, TP, tannins and phenolic compounds than low quality rooibos. Correlations between the compositional parameters and sensory attributes of the infusions indicated that several non-volatile compounds, including enolphenylpyruvic acid-2-glucoside, quercetin-3-glucoside, and iso-orientin, were associated with the characteristic sweet taste of rooibos, while bitterness was related to certain flavonoids such as luteolin, quercetin and aspalathin. The only compound significantly correlated to astringency was rutin, although it is likely that aspalathin and several other monomeric flavonoids also contribute to astringency. The tannin content was not associated with astringency possibly because of the limitations associated with the tannin quantification method. To determine whether compositional changes resulting from steam pasteurisation of rooibos leaves influence the sensory quality of rooibos infusions, differences in the phenolic composition and sensory attributes of infusions, prepared from unpasteurised and pasteurised rooibos, were analysed. Steam pasteurisation significantly reduced the SS, TP and aspalathin content of rooibos infusions, as well as the absorbance, especially at a wavelength of 450 nm. It also resulted in significant reductions in the intensities of most of the aroma and flavour attributes, especially the “green” notes associated with low quality rooibos. After steam pasteurisation the prominent “green” flavour of certain samples was frequently replaced by a “hay” flavour. The taste attributes, sweetness and bitterness, remained unchanged, whereas the astringency of rooibos infusions decreased significantly. / AFRIKAANSE OPSOMMING: Die sensoriese eienskappe en chemiese samestelling van rooibostee is geanaliseer ten einde die mate van variasie van die sensoriese sowel as die chemiese profiel te bepaal, asook om vas te stel of korrelasies bestaan tussen die sensoriese eienskappe en die fenoliese samestelling van rooibostee. Om soveel as moontlik potensiële variasie in te sluit, is 69 rooibos monsters tydens die 2009 oesseisoen van verskillende produksiegebiede versamel. Die monsters is ook verteenwoordigend van die verskillende kwaliteitgrade (A, B, C en D), wat op grond van die voorkoms van die teeblare, en die kleur en geur van die tee toegeken is. Kwantitatiewe beskrywende analise is gebruik om ‘n sensoriese profiel vir elke rooibostee op te stel. Aansienlike variasie in die sensoriese eienskappe is waargeneem. Dit het die behoefte aan gestandaardiseerde terminologie onderskryf, wat gebruik kan word om die term “karakteristieke” rooibos geur in meer detail te omskryf. Spesifieke terme vir aroma, geur, smaak en mondgevoel is geformuleer, en gebruik om ‘n sensoriese wiel vir rooibostee saam te stel. Terme wat die meeste voorgekom het, is gekies om in ‘n sensoriese leksikon vervat te word wat ‘n definisie en ‘n verwysingstandaard vir elke term voorstel. Die “karakteristieke” sensoriese eienskappe van goeie kwaliteit rooibostee kan soos volg gedefinieer word: ’n kombinasie van “heuning”, “houtagtige” en “fynbos-blom” geure met ‘n effense soet smaak en ‘n sagte vrankheid. Aangename “karamel” en “vrugtige-soet” geure is ook waargeneem, terwyl terme soos “groen” en “hooi” met swak kwaliteit rooibostee geassosieer is. Groot variasie in die samestelling van rooibostee is verkry deur kwantifisering van die inhoud van oplosbare vastestowwe (SS), totale polifenole (TP), tanniene, en 14 monomeriese fenoliese verbindings, asook spektrofotometriese kleurmetings. Hoë kwaliteit rooibostee is geassosieer met hoër vlakke van SS, TP, tanniene en fenoliese verbindings in vergelyking met lae kwaliteit rooibos. Korrelasies tussen laasgenoemde parameters en die sensoriese eienskappe het aangedui dat sekere nie-vlugtige verbindings, bv. fenielpirodruiwesuurglukosied, kwersetien-3-glukosied en iso-orientien, geassosieer is met die kenmerkende soet smaak van rooibos, terwyl ‘n bitter smaak geassosieer is met spesifieke flavonoïede soos luteolien, kwersetien and aspalatien. Die enigste verbinding wat betekenisvol gekorreleer het met vrankheid was rutien, maar dit is waarskynlik dat aspalatien en ander monomeriese flavonoïede ook bygedra het tot vrankheid. Die tannieninhoud het nie verband gehou met vrankheid nie, vermoedelik as gevolg van die beperkinge van die chemiese metode vir tannienbepaling. Om te bepaal of stoompasteurisasie van rooibos die sensoriese kwaliteit en chemiese samestelling van rooibostee beïnvloed, is die verskille in fenoliese samestelling en sensoriese eienskappe van die tee, berei van ongepasteuriseerde en gepasteuriseerde rooibos, ondersoek. Stoompasteurisasie het ‘n betekenisvolle verlaging teweegebring van die SS, TP en aspalatien inhoud, sowel as van die absorbansie van die tee, veral by ‘n golflengte van 450 nm. Dit het ook gelei tot ‘n statisties betekenisvolle vermindering van die intensiteit van die meeste aroma en geur eienskappe, veral die sogenaamde “groen” eienskap wat met swak kwaliteit rooibos verbind word. As gevolg van stoompasteurisasie is die opmerklike “groen” geur van sekere ongepasteuriseerde monsters herhaaldelik vervang deur ‘n “hooi” geur. Die smaakeienskappe, soet en bitter, was onveranderd, terwyl vrankheid statisties betekenisvol afgeneem het as gevolg van pasteurisasie.

Thesis (MSc Food Sc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Nectar formulations containing red-fleshed plum pulp and varying amounts of red-fleshed plum skin extract were developed. Red-fleshed plum nectar formulations containing 0, 8, 16, 24, and 32% skin extract were benchmarked against twenty-two commercial beverages containing red, violet and blue fruits. The total soluble solid content, pH, titratable acidity, colour, total polyphenolic, individual polyphenolic, total anthocyanin, and ascorbic acid contents, as well as antioxidant activity (oxygen radical antioxidant capacity (ORAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and ferric reducing/antioxidant power (FRAP)) of the commercial beverages and plum formulations were determined. The plum nectar formulations had similar or higher total polyphenolic content, antioxidant activity, and colour values than the average for the commercial beverages. The individual polyphenolic compounds analysed in the nectar formulations were cyanidin-3-glucoside, cyanidin-3- rutinoside, quercetin-3-glucoside, quercetin-3-rutinoside, quercetin-3-xyloside, and neochlorogenic acid. Increasing polyphenolic content and antioxidant activity was observed with an increase in skin extract content of the formulations. The sensory attributes of the formulations were plum and plantlike aroma, plum and plantlike flavour, sweetness, acidity, and astringency. Increases in plantlike aroma and flavour, acidity, and astringency in conjunction with decreases in plum aroma, plum flavour, and sweetness extract were observed with an increase in skin extract. Consumer analysis indicated that all formulations were acceptable. The 0 and 16% skin extract formulations were most preferred, while the 32% skin extract formulation was least preferred. A shelf-life study was conducted in two phases. In Phase 1, the 0, 16 and 24% skin extract formulations were stored at 0 and 5°C (analysis time points: before pasteurisation, after pasteurisation (week 0), and after 1, 2, 4, 6, 8, 12, 16, 18, 20, and 24 weeks of storage). Chemical analyses conducted included colour, total polyphenolic, individual polyphenolic compound, and total anthocyanin contents, and antioxidant activity (DPPH• scavenging activity). Results from Phase 1 indicated close associations between the 16 and 24% skin extract formulations, and between these formulations and all chemical attributes. Regression analysis of results indicated significant (P 0.05) decreases in red colour, total anthocyanins, cyanidin-3-glucoside, cyanidin-3- rutinoside, DPPH• scavenging activity, total polyphenolic content, quercetin-3-rutinoside, and quercetin- 3-xyloside for formulations stored at 0°C. The total and red colour, total anthocyanins, cyanidin-3- glucoside, and cyanidin-3-rutinoside in formulations stored at 5°C showed similar results. During Phase 2 of the shelf life study, sensory analysis was conducted on the 0 and 24% skin extract formulations stored at 5°C (preparation time points: 0, 1, 2, and 3 months). Sensory attributes, including plum, plantlike, and raisin flavour, sweetness, acidity, and astringency, were stable during storage. Chemical results from Phase 2 were similar to those of Phase 1. The chemical and sensory stability of formulations after 24 weeks of storage in Phase 1 and Phase 2 indicated that, with the exception of the anthocyanin degradation, the formulations could be beneficial to juice industries. Thus, red-fleshed plum nectars have the potential to compete with high-antioxidant fruit beverages. / AFRIKAANSE OPSOMMING: Nektarformulasies wat rooivleis pruimpulp en varieërende hoeveelhede rooivleis pruimskilekstrak bevat, is ontwikkel en ondersoek. Rooivleis pruimnektarformulasies wat 0, 8, 16, 24, en 32% skilekstrak bevat, is vergelyk met twee-en-twintig kommersiële drankies wat rooi, violet en blou vrugte bevat. Die totale oplosbare vastestof, totale polifenoliese, individuele polifenoliese, totale antosianien- en askorbiensuur inhoude, sowel as die pH, titreerbare suurheid, kleur, antioksidant aktiwiteit (suurstofradikale antioksidantkapasiteit (ORAC), 2,2-difeniel-1-pikrielhidrasiel (DPPH) radikaal blussingsaktiwiteit, en ysterreduserende/antikoksidantkrag (FRAP)) van die kommersiële drankies en pruimnektarformulasies, is bepaal. Die pruimnektarformulasies het soortgelyke of hoër totale polifenoliese inhoud, antioksidantaktiwiteit, en kleurwaardes gehad in vergelyking met die gemiddelde vir die kommersiële drankies. Die individuele polifenoliese verbindings wat in die nektarformulasies geanaliseer is, was sianidien-3-glukosied, sianidien-3-rutinosied, kwersetien-3-glukosied, kwersetien-3-rutinosied, kwersetien-3-xylosied, en neochlorogeniese suur. ‘n Toenames in die kleurwaardes, polifenoliese inhoud, en antioksidantaktiwiteit is waargeneem met ‘n toename in skilekstrak is in die formulasies. Die sensoriese eienskappe van die formulasies was pruim- en plantagtige aroma, pruim- en plantagtige geur, soetheid, suurheid, en frankheid. Toenames in plantagtige aroma en geur, suurheid en frankheid, sowel as ‘n afname in pruimaroma, pruimgeur, en -soetheid, is met ‘n toename in skilekstrak waargeneem. Verbruikersanalise het aangedui dat al die formulasies aanvaarbaar was. Die 0 en 16% skilekstrakformulasies was die mees aanvaarbaarste, terwyl die 32% skilekstrakformulasie die minste aanvaarbaar geag is. ‘n Rakleeftydstudie is in twee fases gedoen. In Fase 1 is die 0, 16, en 24% skilekstrakformulasies by 0 en 5°C gestoor (analiseringstydpunte: voor pasturisasie, na pasturisasie (week 0), en na 1, 2, 4, 6, 8, 12, 16, 18, 20, en 24 weke van berging). Chemiese analise wat gedoen is, sluit totale polifenoliese, individuele polifenoliese verbinding, en totale antosianien inhoude, sowel as kleur en antioksidantaktiwiteit (DPPH• blussingsaktiwiteit) in. Resultate van Fase 1 het ‘n nou verband tussen die 16 en 24% skilekstrakformulasies, sowel as tussen hierdie formulasies en hul chemiese kenmerke aangedui. Regressie-analise van resultate het betekenisvolle (P 0.05) afnames geïllustreer in rooi kleurwaardes, DPPH• blussingsaktiwiteit, sowel as totale antosianiene, sianidien-3-glukosied, sianidien-3-rutinosied, totale polifenoliese, kwersetien-3-rutinosied, en kwersetien-3-xylosied inhoude van die formulasies wat by 0°C gestoor is. Die totale kleur-, rooi kleurwaardes, sowel as totale antosianien, sianidien-3-glukosied, en sianidien-3-rutinosied in die formulasies wat by 5°C gestoor is, het soortgelyke resultate gegee. Gedurend Fase 2 van die rakleeftydstudie is sensoriese analise op die 0 en 24% skilekstrakformulasies wat by 5°C gestoor is, gedoen (voorbereidingstydpunte: 0, 1, 2, en 3 maande). Sensoriese eienskappe, insluitend pruim-, plantagtige-, en rosyntjiesmake, soetheid, suurheid, en frankheid, was stabiel gedurende berging. Chemiese resultate van Fase 2 was soortgelyk aan dié van Fase 1. Die chemiese en sensoriese stabiliteit van die formulasies na 24 weke van opberging in Fase 1 en Fase 2 nieteenstaande antosianienafname, het aangedui dat die formulasies voordelig kan wees vir die vrugtedrankiebedryf. Dus het rooivleis pruimnektars die vermoeë om met hoë antioksidant vrugtedrankies mee te ding.

Thesis (MSc Food Sc)--University of Stellenbosch, 2011. / Please refer to full text to view abstract.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The objective of this study was to investigate the impact of season on the composition and quality of male and female blesbok (Damaliscus pygargus phillipsi) muscles (Longissimus dorsi, Biceps femoris, Semimembranosus, Semitendinosus, Infraspinatus and Supraspinatus). The latter was quantified on the chemical composition (moisture, protein, fat and ash contents), fatty acid profile, mineral composition and physical attributes (pH, colour, drip and cooking loss, water holding capacity and tenderness) of the selected muscles. All of the blesbok muscles had higher (p<0.01) mean protein contents (20.6 g.100 g-1 to 23.1 g.100 g-1) when the plane of nutrition was believed to be higher (spring of 2009). A strong negative correlation (r = – 0.82; p<0.01) existed between the moisture and protein contents of the blesbok muscles. The Longissimus dorsi muscle had the highest (p<0.01) mean intramuscular fat content (3.4 g.100 g-1) when the plane of nutrition was higher. The chemical composition of the Longissimus dorsi, Biceps femoris, Semitendinosus and forequarter muscles (Infraspinatus and Supraspinatus) was affected least by the seasonal differences in the plane of nutrition and activity levels of the blesbok at the study area. However, season had a larger impact on the chemical composition of the Semimembranosus muscle. Season did not have a significant impact on the fatty acid profile of blesbok muscles, but the difference in the fatty acid profiles between male and female muscles was significant. A Principal Component Analysis (PCA) bi-plot indicated that female blesbok muscles were associated with a higher saturated fatty acid (SFA) and mono-unsaturated fatty acid (MUFA) content. Male blesbok muscles had higher (p<0.01) proportions of total polyunsaturated fatty acids (PUFA) (40.15 ± 5.39) and polyunsaturated to saturated fatty acid ratios (P:S) (0.85 ± 0.18), in comparison to female muscles (27.18 ± 8.04 and 0.54 ± 0.20, respectively). Differences in the anatomical locations of the selected blesbok muscles furthermore influenced the fatty acid profiles. The less active Longissimus dorsi muscle had higher (p<0.05) total PUFA (38.34 ± 8.62), total omega-6 (ω6) PUFA (34.46 ± 7.83), total ω3 PUFA (3.44 ± 0.84) and P:S (0.85 ± 0.24) contents, in comparison to the Infraspinatus muscle (28.96 ± 8.65, 26.23 ± 7.86, 2.31 ± 0.70 and 0.56 ± 0.19, respectively) and Supraspinatus muscle (28.85 ± 9.23, 26.05 ± 8.24, 2.28 ± 0.76 and 0.55 ± 0.21, respectively). The hindquarter muscles (Biceps femoris, Semimembranosus and Semitendinosus) had intermediate fatty acid content. Season had an impact on the calcium and zinc contents of blesbok muscles. The calcium content was higher (p<0.05) in the muscles of the animals harvested in spring (6.92 ± 1.94) compared to winter (5.61 ± 1.79). The zinc content was higher (p<0.05) in the muscles of male blesbok harvested in winter (4.04 ± 1.70) compared to spring (3.41 ± 1.67). The mineral composition was furthermore significantly different between the selected blesbok muscles. The Biceps femoris muscle had the highest (p<0.05) potassium (183.25 ± 12.79), phosphorus (180.21 ± 10.36) and magnesium (32.18 ± 1.72) content, while the sodium and calcium content was highest in the forequarter muscles. The Longissimus dorsi muscle had the highest (p<0.05) iron (3.67 ± 0.51), but significantly lower zinc content (1.63 ± 0.28), in comparison to the forequarter muscles. The pH value ≈24 h post mortem was higher (p<0.05) in the Longissimus dorsi muscle of the animals harvested in spring (5.60) compared to winter (5.54). The CIE a* (14.63 ± 0.86) and chroma (17.09 ± 0.63) values were higher (p<0.05) for winter than for male blesbok meat in spring (13.62 ± 1.08 and 16.10 ± 1.03, respectively). The latter values were also higher (p<0.05) for male compared to female (13.49 ± 0.88 and 16.22 ± 0.98) blesbok meat, at the end of the mating season (winter). The forequarter muscles had higher chroma values in comparison with the hindquarter muscles, which had higher (p<0.01) hue-angle values. Season had no influence (p<0.05) on the drip loss percentages and tenderness of blesbok muscles. The drip loss percentages were lowest (p<0.05) in the Biceps femoris and Semimembranosus muscles. The Infraspinatus and Supraspinatus muscles had the lowest (p<0.01) Warner Bratzler shear force values (20.89 ± 3.23 and 24.90 ± 5.35 N, respectively). Seasonal differences in the chemical composition of blesbok muscles were statistically significant. However, these differences were numerically small and it is therefore debatable whether they are of any biological relevance relating to human nutrition. The differences in the fatty acid profile and mineral composition as well as the physical meat quality attributes of blesbok muscles were more attributed to differences in the anatomical locations of the selected muscles, as opposed to the impact of season or gender. / AFRIKAANSE OPSOMMING: Die doel van die studie was om die impak van seisoen op die samestelling en kwaliteit van blesbok (Damaliscus pygargus phillipsi) spiere (Longissimus dorsi, Biceps femoris, Semimembranosus, Semitendinosus, Infraspinatus en Supraspinatus) te bepaal. Die seisoenale impak was gekwantifiseer op die chemiese samestelling (vog-, proteïen-, vet- en asinhoud), vetsuurprofiel, mineraal samestelling en fisiese eienskappe (pH, kleur, drup- en kookverlies, water houvermoë en taaiheid) van die geselekteerde spiere. Met ʼn hoër voedingspeil (lente 2009) het elkeen van die spiere gemiddeld ʼn hoër (p<0.01) proteïeninhoud (20.6 g.100 g-1 tot 23.1 g.100 g-1) gehad. ‘n Sterk negatiewe korrelasie (r = – 0.82; p<0.01) het bestaan tussen die vog- en proteïeninhoud van die blesbokspiere. Met ʼn hoër voedingspeil het die Longissimus dorsi spier die hoogste (p<0.01) gemiddelde intramuskulêre vetinhoud (3.4 g.100 g-1) gehad. Seisoenale verskille in die voedingspeil en aktiwiteitsvlakke van dié blesbokke het minimale verskille in die chemiese samestelling van die Longissimus dorsi, Biceps femoris, Semitendinosus en voorkwartspiere (Infraspinatus en Supraspinatus) tot gevolg gehad. Daar was wel seisoenale verskille in die chemiese samestelling van die Semimembranosus spier. Seisoen het nie ʼn beduidende invloed op die vetsuurprofiel van die blesbokspiere gehad nie, maar daar was wel beduidende (p<0.05) verskille tussen geslagte. Soos aangedui deur ʼn hoofkomponent-analise (PCA) bi-plot, was die spiere van die vroulike blesbokke meer geassosieer met hoër versadigde en mono-onversadigde vetsuursamestellings. Die spiere van die manlike diere het hoër (p<0.01) proporsies poli-onversadigde vetsure (PUFA) (40.15 ± 5.39) asook hoër poli-onversadigde tot versadigde vetsuur verhoudings (P:S) gehad (0.85 ± 0.18) in vergelyking met die spiere van die vroulike diere (onderskeidelik 27.18 ± 8.04 en 0.54 ± 0.20). Die vetsuurprofiel van blesbokspiere was ook beïnvloed deur die anatomiese ligging van die spiere. Die minder aktiewe Longissimus dorsi spier het ʼn hoër (p<0.05) totale PUFA (38.34 ± 8.62), totale omega-6 (ω6) PUFA (34.46 ± 7.83), totale ω3 PUFA (3.44 ± 0.84) en P:S (0.85 ± 0.24) inhoud gehad in vergelyking met die Infraspinatus spier (onderskeidelik 28.96 ± 8.65, 26.23 ± 7.86, 2.31 ± 0.70 en 0.56 ± 0.19) en Supraspinatus spier (onderskeidelik 28.85 ± 9.23, 26.05 ± 8.24, 2.28 ± 0.76 en 0.55 ± 0.21). Die agterkwartspiere (Biceps femoris, Semimembranosus en Semitendinosus) het intermediêre vetsuursamestellings gehad. Seisoen het ʼn invloed op die kalsium- en sinkinhoud van die blesbokspiere gehad. In die lente het die spiere gemiddeld ʼn hoër (p<0.05) kalsiuminhoud gehad (6.92 ± 1.94), in vergelyking met dié van winter (5.61 ± 1.79). Die manlike spiere van die blesbokke wat in winter geoes is, het weer ʼn hoër (p<0.05) sinkinhoud (4.04 ± 1.70) in vergelyking met dié van die lente (3.41 ± 1.67) gehad. Verder het die mineraalinhoud van die geselekteerde blesbokspiere betekenisvol van mekaar verskil. Die Biceps femoris spier het die hoogste (p<0.05) kalium- (183.25 ± 12.79), fosfor- (180.21 ± 10.36) en magnesiuminhoud (32.18 ± 1.72) gehad. Die natrium- en kalsiuminhoud was hoër in die voorkwartspiere. Die Longissimus dorsi spier het die hoogste (p<0.05) ysterinhoud (3.67 ± 0.51) gehad. Laasgenoemde het ʼn beduidend laer sinkinhoud (1.63 ± 0.28) in vergelyking met die voorkwartspiere gehad. Die Longissimus dorsi spiere van die blesbokke wat in die lente geoes is, het gemiddeld hoër pH-waardes by ≈24 uur post mortem gehad (5.60) in vergelyking met die pH-waardes van dié spiere in winter (5.54). Die CIE a*- (14.63 ± 0.86) en chroma-waardes (17.09 ± 0.63) van die manlike blesbokspiere was hoër (p<0.05) in die winter as in die lente (onderskeidelik 13.62 ± 1.08 en 16.10 ± 1.03). Aan die einde van die paartyd (winter) het die manlike blesbokke se spiere ook hoër (p<0.05) CIE a*- en chroma-waardes as die vroulike blesbokspiere (13.49 ± 0.88 en 16.22 ± 0.98) gehad. Die voorkwartspiere het gemiddeld hoër (p<0.05) chroma-waardes as die agterkwartspiere gehad, maar laasgenoemde het weer hoër (p<0.01) hue-angle waardes as die voorkwartspiere gehad. Seisoen het geen effek (p<0.05) op die drupverlies persentasies en taaiheid van die blesbokspiere gehad nie. Die Biceps femoris en Semimembranosus spiere het wel die laagste (p<0.05) drupverlies persentasies gehad. Die Infraspinatus en Supraspinatus spiere het weer die laagste (p<0.01) taaiheid (onderskeidelik 20.89 ± 3.23 en 24.90 ± 5.35) in vergelyking met die Longissimus dorsi, Biceps femoris, Semimembranosus en Semitendinosus spiere gehad (onderskeidelik 30.57 ± 6.69, 27.35 ± 3.42, 28.65 ± 4.48 en 31.51 ± 5.63). Alhoewel daar in die studie statisties beduidende seisoenale verskille in die chemiese samestelling van die blesbokspiere was, is die verskille numeries klein en is dit debatteerbaar of dié verskille enigsins biologies van toepassing is op menslike voeding. Verder het die anatomiese ligging van die geselekteerde blesbokspiere in die studie ʼn groter invloed op die verskille in die vetsuurprofiel, mineraal samestelling asook die fisiese eienskappe van die spiere gehad, in vergelyking met die impak van die oes-seisoen en die effek van geslag.

Thesis (MSc Food Sc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Over the past two decades, there has been an increase in the use of water sources for irrigation, as well as an increase in Escherichia coli outbreaks linked to fresh produce. The full extent and type of E. coli contamination present in natural water sources is unknown and the contamination sources have also not been confirmed. The aim of this study was to enumerate and characterise E. coli from both irrigation water and potential contamination source sites. Total coliform and E. coli counts found in contamination source sites were as high as log 7.114 and log 6.912 MPN.100 mL-1, respectively. Total coliform and E. coli counts for irrigation sites were lower, with maximum counts of log 5.788 and log 5.768 MPN.100 mL-1, respectively. It was found that more than one third (5/14 = 35.71%) of the irrigation sites had E. coli counts exceeding the guidelines (<1 000 counts.100 mL-1) for ‘safe’ irrigation water for fresh produce (<1 000 counts.100 mL-1) as set by the Department of Water Affairs (DWA) and World Health Organisation (WHO), making the water unsuitable for the irrigation of fresh produce. Phylogenetic subgroups (A0, A1, B1, B22, B23, D1 and D2) and the MALDI Biotyper system (PCA dendrogram) were used to create a fingerprint of each E. coli isolated from the environment. These were then used to link E. coli strains from irrigation water to their most probable contamination origin. Escherichia coli population structure was found in this study, to be better suited for linking E. coli strains from irrigation water to their most likely source, than just applying the phylogenetic grouping. The MALDI Biotyper data in combination with the phylogenetic subgroup assignment was then used to group similar strains and link E. coli from irrigation water to their contamination sources by comparing population structures. Strains isolated from surface and groundwater showed similar distribution patterns, but groundwater strains showed a population structure more indicative of porcine and bovine origin, while surface water showed population characteristics which could not be used to make conclusive links between the irrigation water and suspected contamination sources. When investigating the population structures of individual sample sites, it was found that phylogenetic subgroups A0, A1 and B1 frequently made up the bulk of the E. coli population. It was also found that linking individual irrigation sites to contamination sources was successful, as irrigation site Berg-2 was found to have a similar population structure to contamination source site Plank-1 which represents human pollution from an informal settlement. This led to the conclusion that Berg-2 was being contaminated by human pollution, most probably from an informal settlement. Upon further investigation it was found that Berg-2 is downstream of an informal settlement, proving that E. coli population structure is a successful means of microbial source tracking (MST). Virulence factors of the 153 E. coli isolated during the study were identified and the potential risk associated with using the investigated irrigation water for irrigation of fresh produce, was determined. Two enteropathogenic E. coli (EPEC) strains were isolated from the irrigation water, one from the Plankenburg River water, and the other from a borehole in the Drakenstein area. The latter indicates that borehole water is not as safe as was once thought, and that there are bacterial contaminants finding their way into groundwater. The occurrence of an EPEC strain in river water shows that neither ground nor surface water is guaranteed to be safe, and that treatment of water being used for the irrigation of fresh produce should be implemented. / AFRIKAANSE OPSOMMING: Oor die afgelope twee dekades was daar nie net 'n toename in die gebruik van alternatiewe waterbronne vir besproeiing nie, maar ook 'n toename in uitbrake van Escherichia coli uitbrake wat aan vars produkte gekoppel kan word. Die tipe E. coli-besmetting wat in natuurlike waterbronne teenwoordig is, is onbekend en die besmettingsbron is ook nog nie bevestig nie. Daarom was die doel van hierdie studie om die voorkomssyfer van E. coli van beide besproeiingswater en potensiële kontaminasiebronne te bepaal, asook om die E. coli te karakteriseer. Totale kolivorme en E. coli-tellings wat in kontaminasiebronne gevind is, het ‘n maksimum van log 7,114 en log 6,912 MPN.100 mL-1 onderskeidelik bereik, terwyl die totale kolivorme en E. coli-tellings vir besproeiingswater laer was, met 'n maksimum van log 5,788 en 5,768 MPN.100 mL-1, onderskeidelik. Dit is bevind dat meer as 1/3 (5/14 = 35,71%) van die besproeiingswaterbronne meer E. coli bevat as wat toegelaat word in die riglyne vir "veilige" besproeiingswater vir vars produkte (<1 000 fekale koliforme.100 mL-1) wat deur die Departement Waterwese (DWA) en die Organisasie vir Wêreldgesondheid (WHO) aanbeveel word. Filogenetiese subgroepe (A0, A1, B1, B22, B23, D1 en D2) en die ‘MALDI Biotyper’-stelsel (PKA dendrogram) is gebruik om unieke profiele vir elke geïsoleerde E. coli te skep. Dié profiele is daarna gebruik om E. coli-stamme van besproeiingswater te koppel aan die mees waarskynlike oorsprong van kontaminasie. Daar is in hierdie studie bevind dat die E. coli-populasiestruktuur beter geskik was vir die koppeling van E. coli-stamme van besproeiingswater na hul mees waarskynlikste bron, as net die toepassing van die filogenetiese groepering. Dit was toe gevind dat E. coli wat uit oppervlak- en grondwater geïsoleer is, soortgelyke verspreidingspatrone het, maar grondwaterstamme se bevolkingstruktuur is meer aanduidend van fekale besmetting deur varke en beeste, terwyl oppervlakwater se bevolkingseienskappe nie duidelik genoeg was om ‘n gevolgtrekking oor moontlike bronne van besmetting te maak nie. Toe die populasiestruktuur van die individuele bemonsteringspunte ondersoek is, is daar bevind dat die filogenetiese subgroepe A0, A1 en B1 dikwels die meeste tot die E. coli bevolking bydra. Daar is ook bevind dat die koppeling van isolate in individuele besproeiingswaterbronne met hul mees waarskynlike bronne van kontaminasie suksesvol was. Besproeiingswater van Berg-2 het 'n soortgelyke populasiestruktuur as Plank-1 wat beskou is as ‘n kontaminasiebron. Dit het gelei tot die gevolgtrekking dat Berg-2 heel waarskynlik deur menslike besoedeling beïnvloed word, soos Plank-1, en dat daar moontlik ook ‘n informele nedersetting by Berg-2 betrokke is. Na verdere ondersoek is gevind dat Berg-2 inderdaad ook stroomaf van 'n ander informele nedersetting geleë is, wat bewys dat die E. coli-populasiestruktuur 'n suksesvolle manier is om E. coli kontaminasie te verbind met besproeiingswater. Patogeniese faktore, wat in E. coli voorkom en maagkieme veroorsaak, is vooraf getoets in elkeen van die 153 E. coli-isolate wat tydens die studie geïdentifiseer is. Twee ‘enteropathogenic’ E. coli (EPEC)-stamme is uit die besproeiingswater geïsoleer: een uit die Plankenburgrivier (Plank-3), en die ander uit 'n boorgat in die Drakenstein-gebied (Boorgat A1). Hierdie inligting dui aan dat boorgatwater nie so veilig is as wat voorheen vermoed is nie, en dat bakteriese kontaminasie wel vookom wat nie alleen die grondwater besmet nie, maar ook daarin oorleef. Die voorkoms van die EPEC-stamme in hierdie studie is ‘n aanduiding dat beide grond- en opppervlakwater ewe gevaarlik kan wees, en dat daar dus geen waarborg vir die veiligheid van die water is nie. Die behandeling van grond- en oppervlakwater, wat vir die besproeiing van vars produkte gebruik word, moet daarom ernstig oorweeg word om moontlike uitbrake van E. coli op vars produkte te verhoed.

Thesis (MSc Food Sc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: A wide variety of traditionally and commercially fermented milks are commonly consumed in various countries of Sub-Saharan Africa. Commercially fermented milk is produced on an industrial scale according to well-managed, standardised production processes and starters are used to initiate fermentation. Traditionally fermented milk is prepared domestically and fermentation occurs spontaneously at ambient temperatures. Lactic acid bacteria (LAB) are responsible for milk fermentation during which they convert the milk carbohydrates to lactic acid, carbon dioxide, alcohol and other organic metabolites. Acetic acid bacteria (AAB), yeasts and mycelial fungi have also been isolated from fermented milks. In this study the microbial consortium present in three traditionally fermented milks, namely omashikwa from Namibia, masse from Mozambique and chekapmkaika from Uganda and two commercially fermented milks, namely chambiko from Malawi and omaere from Namibia, were isolated and enumerated on six different selective media that included MSR + C (specific for lactobacilli), KCA + TTC (specific for lactococci), KCA + V (specific for leuconostocs), MRS + E (specific for AAB), MEA (specific for mycelial fungi) and YPD (specific for yeasts). No significant differences were found between the enumeration values obtained for the three chambiko samples, as well as for enumeration values obtained for the two omaere samples on each of the selective media, indicating low sample variance. Significant differences between enumeration values obtained for the three omashikwa samples were found on all six selective media. Significant differences between enumeration values of the three masse samples and both the chekapmkaika samples were also observed on the selective media. In addition to this, significant differences were observed between average enumeration values obtained for each media between the masse and chekapmkaika, the chambiko and omaere, as well as when the traditional and commercial milks were compared. According to the average enumeration values obtained on each media selective for LAB, the highest bacterial counts were detected on KCA + TTC medium for omaere (2.3 x 106 cfu.ml-1), KCA + V for chambiko (1.8 x 105 cfu.ml-1), KCA + TTC for omashikwa and MRS + C for masse and chekapmkaika (6.2 x 106 and 2.0 x 103 cfu.ml-1, respectively). After isolation and enumeration of the microbes present in each milk, bacterial isolates on the media selective for LAB and AAB were obtained according to the Harrison Disk method. These isolates were identified by amplifying a 1.5 kilobase (kb) part of the 16S ribosomal RNA (rRNA) gene using the polymerase chain reaction (PCR), followed by DNA sequencing. The isolates were identified by comparing the sequences obtained to sequences listed in the NCBI database using the BLAST algorithm and searching for the closest relative. The main LAB group present in the omaere was lactococci (94%), in chambiko and chekapmkaika it was lactobacilli (30% and 45%, respectively), in omashikwa it was enterococci (43%) and in masse it was leuconostocs (68%). The same microbial species were present on a number of the selective media used in this study. Lactococcus spp., Enterococcus spp. and Lactobacillus spp. were isolated from MRS + C, KCA + TTC, KCA + V and MRS + E and Leuconostoc spp. were isolated from MRS + C, MRS + E and KCA + V. Hygienic standards during traditional milk fermentation is often poor and, therefore, microbial contaminants were isolated from the traditional milk and these included Acinetobacter johnsonii and Klebsiella pneumoniae from KCA + V, Mesorhizobium loti, Acinetobacter radioresistens, Escherichia coli, Staphylococcus spp., Kluyvera georgiana, Enterobacter spp. and Klebsiella oxytoca from KCA + TTC, Staphylococcus spp. from MRS + C and Bacillus spp. from MRS + E. Since the media used for the isolation of the LAB and AAB in this study were not selective further identification of the enumerated microbes is of importance for the identification of the microbial groups present in each fermented milk. The data obtained in this study clearly shows that fermented milks from Sub-Saharan Africa vary significantly from each other in terms of microbial numbers, microbial diversity and the dominant microbial groups present. The microbial diversity of the traditionally fermented milks was more diverse than the microbial diversity of the commercially fermented milks. LAB strains isolated from these traditionally fermented milks can be used to develop novel starters and as a result new commercially fermented dairy products with unique aromas, tastes and characteristics can be produced. / AFRIKAANSE OPSOMMING: 'n Wye verskeidenheid tradisioneel en kommersieel gefermenteerde melk produkte word algeneem verbruik in verskeie lande van Sub-Sahara Afrika. Kommersieel gefermenteerde melk word geproduseer op groot skaal, deur deeglik bestuurde gestandardiseerde produksieprosesse en 'n beginkultuur word gebruik om fermentasie te inisieer. Tradisioneel gefermenteerde melk word tuis gemaak en fermentasie gebeur spontaan by kamertemperatuur. Melksuurbakterieë (MSB) is verantwoordelik vir melkfermentasie waartydens die bakterieë koolhidrate omskakel na melksuur, koolstofdioksied, alkohol en ander organiese sure. Asetaatsuurbakterieë (ASB), giste en miseliale fungi is ook al van gefermenteerde melk geïsoleer. In hierdie studie is die mikrobiese konsortium teenwoordig in drie soorte tradisioneel gefermenteerde melk, naamlik omashikwa van Namibië, masse van Mosambiek en chekapmkaika van Uganda en twee soorte kommersieel gefermenteerde melk, naamlik chambiko van Malawi en omaere van Namibië, geïsoleer en getel op ses verskillende selektiewe groeimedia insluitend MRS + C (spesifiek vir lactobacilli), KCA + TTC (spesifiek vir lactococci), KCA + V (spesifiek vir leuconostocs), MRS + E (spesifiek vir ASB), MEA (spesifiek vir miseliale fungi) en YPD (spesifiek vir giste). Geen betekenisvolle verskille is gevind tussen die mikrobiese tellings verkry vir die drie chambiko monsters nie, sowel as tussen die mikrobiese tellings verkry vir die twee omaere monsters, op elk van die selektiewe groeimedia, wat dui op lae monster variansie. Betekenisvolle verskille is gevind tussen die mikrobiese tellings verkry vir die drie omashikwa monsters op al ses selektiewe groeimedia. Betekenisvolle verskille is ook waargeneem tussen die mikrobiese tellings van die drie masse monsters en beide die chekapmkaika monsters op die selektiewe groeimedia. Daarbenewens is betekenisvolle verskille waargeneem tussen gemiddelde mikrobiese tellings verkry vir elke groeimedium tussen die masse en chekapmkaika, die chambiko en omaere asook toe die tradisionele en kommersiële melk produkte met mekaar vergelyk is. Volgens die gemiddelde mikrobiese tellings verkry op elk van die groeimedia selektief vir MSB, is die hoogste mikrobiese telling waargeneem op KCA + TTC medium vir omaere (2.3 x 106 kve.ml-1), KCA + V vir chambiko (1.8 x 105 kve.ml-1), KCA + TTC vir omashikwa en MRS + C vir masse en chekapmkaika (6.2 x 106 en 2.0 x 103 kve.ml-1, respektiewelik). Na die isolasie en tel van die mikrobes teenwoordig in elke melk is bakteriese isolate op die media selektief vir MSB en ASB verkry volgends die Harrison Disk metode. Hierdie isolate is geïdentifiseer deur amplifikasie van „n 1.5 kilobasis (kb) gedeelte van die 16S ribosomale RNS (rRNS) geen deur gebruik te maak van die polimerase kettingreaksie gevolg deur DNS klonering. Die isolate is geïdentifiseer deur die gekloneerde insetsels se volgordes te vergelyk met volgordes beskikbaar op die NCBI webwerf deur van die BLAST algoritme gebruik te maak en die naas verwante insetsel op te spoor. Die hoof MSB groep teenwoordig in die omaere was lactococci (94%), in chambiko en chekapmkaika was dit lactobacilli (30% en 45%, respektiewelik), in die omashikwa was dit enterococci (43%) en in die masse was dit leuconostocs (68%). Dieselfde mikrobiese spesies was teenwoordig op verskeie van die selektiewe groeimedia gebruik in hierdie studie. Lactococcus spp., Enterococcus spp. en Lactobacillus spp. is geïsoleer van MRS + C, KCA + TTC, KCA + V en MRS + E en Leuconostoc spp. is geïsoleer van MRS + C, MRS + E en KCA + V. Higiëniese standaarde tydens tradisionele melkfermentasie is dikwels swak en dus is mikrobiese kontaminante geïsoleer van die tradisionele melk produkte insluitend Acinetobacter johnsonii en Klebsiella pneumoniae van KCA + V, Mesorhizobium loti, Acinetobacter radioresistens, Escherichia coli, Staphylococcus spp., Kluyvera georgiana, Enterobacter spp. en Klebsiella oxytoca van KCA + TTC, Staphylococcus spp. van MRS + C en Bacillus spp. van MRS + E. Aangesien die media wat gebruik is vir die isolasie van die MSB en ASB in hierdie studie nie selektief was nie, is verdere identifikasie van die getelde mikrobes belangrik vir die identifikasie van die mikrobiese groepe teenwoordig in elke melk. Die data verkry in hierdie studie dui aan dat gefermenteerde melk produkte van Sub-Sahara Afrika betekenisvol van mekaar verskil in terme van mikrobiese getalle, mikrobiese diversiteit en die dominante mikrobiese groepe teenwoordig. Die mikrobiese diversiteit van die tradisioneel gefermenteerde melk produkte was meer divers as die mikrobiese diversiteit van die kommersieel gefermenteerde melk produkte. MSB spesies geïsoleer van hierdie tradisioneel gefermenteerde melk produkte kan gebruik word om nuwe beginkulture te ontwikkel en gevolglik kan nuwe kommersieel gefermenteerde suiwelprodukte met unieke aromas, smake en eienskappe geproduseer word.

Thesis (MScFoodSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The phenolic composition of Cyclopia species is believed to be partially responsible for the numerous health promoting properties associated with their extracts. Current quality control measures do not accommodate variation in phenolic profiles of Cyclopia species. In this study, comprehensive high performance liquid chromatography (HPLC) methods were developed for the improved characterisation of the phenolic composition of aqueous extracts of two Cyclopia species (C. subternata and C. maculata). The methods were developed to be suitable for both routine quantitative analysis on conventional HPLC instrumentation, and the construction of chromatographic fingerprints for further data analysis. The latter entailed similarity analysis and prediction of total antioxidant capacity (TAC). Using a methodical approach, two separate HPLC methods, using diode array detection (DAD), were developed and validated for the analysis of aqueous extracts prepared from unfermented (green) and fermented plant material of C. subternata and C. maculata. Separation was achieved using the same method parameters (column, temperature, mobile phases), except for differing mobile phase gradients. Hyphenation of the developed HPLC methods with mass spectrometry (MS) and tandem MS allowed the confirmation of phenolic compounds previously identified in Cyclopia, and the tentative identification of several additional compounds in Cyclopia species, which are reported here for the first time. These included apigenin-6,8-di- C-glucoside, 3-hydroxyphloretin-30,50-di-C-hexoside, eriodictyol-di-C-glucoside, iriflophenone-di-O,C-hexoside, hydroxymangiferin and hydroxyisomangiferin. Subsequently, a large number of aqueous extracts of randomly selected green C. subternata (n = 64) and C. maculata (n = 50) plant material samples were analysed. Large quantitative variations were observed on intra- and inter-species levels. Cyclopia maculata extracts contained almost six times more mangiferin than extracts from C. subternata. HPLC-DAD analysis produced duplicate fingerprints for each extract which were consequently used for further analysis. The chromatographic fingerprint of a bioactive extract of each species was included in the respective data sets. Similarity analysis was conducted between the fingerprints from the randomly selected extracts and the corresponding active extract. For each species several extracts were determined to have similar “activity” as that of the active extract (n = 15 for C. subternata and n = 45 for C. maculata). Compounds potentially responsible for the activity were tentatively identified with the aid of principal component analysis (PCA) in combination with similarity analysis. PCA was more effective in identifying small differences between fingerprints than similarity analysis based on the correlation coefficients (r) alone. Furthermore, multivariate data analysis was used to construct partial least squares (PLS) regression models for the prediction of TAC from fingerprint data of each species, and available data from two microplate TAC assays. The construction of the models was successful with reasonable errors (< 10%), and permitted the determination of compounds of interest for future research. These included compounds of known identity that had large positive contributions toward the predictions of TAC, or unknown compounds that had small UV signals, but relatively large positive contributions to the models. / AFRIKAANSE OPSOMMING: Die talle gesondheidbevorderingseienskappe van ekstrakte van Cyclopia spesies word gedeeltelik geassosieer met hul fenoliese samestelling. Huidige kwaliteitskontrolemaatreëls is nie in staat om die variasie wat in die fenoliese profiele van die spesies voorkom, te akkommodeer nie. Omvattende hoë druk vloeistof chromatografiese (HPLC) metodes is vir twee Cyclopia spesies, naamlik C. subternata en C. maculata, in hierdie studie ontwikkel vir beter karakterisering van die fenoliese samestelling van waterekstrakte van dié spesies. Die metodes moes ook geskik wees vir roetine analise van C. subternata en C. maculata ekstrakte op konvensionele HPLC instrumentasie, en vir die opstel van chromatografiese vingerafdrukke (fenoliese samestellingsprofiele) vir verdere data analise, soos gelykvormigheidsanalise en die voorspelling van die totale antioksidantkapasiteit (TAC). Twee HPLC metodes, wat van ’n ultraviolet-diode detektor (DAD) gebruik maak, is ontwikkel deur ’n sistematiese benadering te volg. Die onderskeie metodes is vir die ontleding van waterekstrakte van groen (ongefermenteerde) en gefermenteerde plantmateriaal van C. subternata en C. maculata gevalideer. Ongeag die spesie is optimale skeiding met dieselfde kolom, mobiele fase en kolom-temperatuur bereik, maar met verskillende mobiele fase gradiënte. Analise met massaspektrometrie (MS) en tandem MS het die teenwoordigheid van fenoliese verbindings, wat voorheen in Cyclopia spesies geidentifiseer is, bevestig. Verder is ook ’n aantal verbindings vir die eerste keer in Cyclopia tentatief geidentifiseer. Dit sluit apigenien-6,8-di-C-glukosied, 3- hidroksiefloretien-30,50-di-C-heksosied, eriodiktiol-di-C-glukosied, iriflofenoon-di-O,C-heksosied, hidroksiemangiferien en hidroksie-isomangiferien in. Vervolgens is ’n groot aantal ewekansig gekose waterekstrakte van beide groen C. subternata (n = 64) en C. maculata (n = 50) plantmateriaal geanaliseer, en groot kwantitatiewe variasie op intra- en inter-spesievlak waargeneem. Cyclopia maculata ekstrakte het byvoorbeeld byna ses maal die mangiferieninhoud van C. subternata ekstrakte gehad. HPLC-DAD analise van die ekstrakte het duplikaat vingerafdrukke van elke ekstrak geproduseer, wat vir verdere data analise gebruik is. Die chromatografiese vingerafdruk van ’n bioaktiewe ekstrak van elke spesie was by die onderskeie datastelle ingesluit. Gelykvormigheidsanalise is tussen vingerafdrukke van die ewekansig gekose ekstrakte en die ooreenstemmende aktiewe ekstrak uitgevoer. Vir elke spesie is ’n aantal “aktiewe” ekstrakte aangewys (n = 15 vir C. subternata en n = 45 vir C. maculata). Die verbindings wat potensieel verantwoordelik kan wees vir die aktiwiteite is met behulp van hoofkomponentontleding (PCA) in kombinasie met gelykvormigheidsanalise, tentatief aangewys. PCA was egter meer effektief om klein verskille tussen vingerafdrukke aan te dui, in vergelyking met gelykvormigheidsanalise wat slegs op die korrelasie koëffisiënt (r) gebaseer is. Meerveranderlike data analiese is gebruik om “gedeeltelike kleinste kwadrate” (PLS) regressiemodelle, vir die voorspelling van die TAC van beide spesies te bou. Die voorspelling is gebaseer op hul vingerafdruk data en TAC data van twee TAC mikroplaat metodes. Die model-konstruksie was suksesvol met aanvaarbare voorspellingsfoute (< 10%). Verbindings van belang kon ook bepaal word. Dit sluit bekende verbindings in wat groot positiewe bydraes ten opsigte van die voorspelling van TAC getoon het, asook ongeidentifiseerde verbindings wat klein UV-seine getoon het, maar relatiewe groot bydraes tot die modelle gehad het.

Thesis (MScFoodSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Modern consumers are health conscious and are shifting towards more naturally produced products such as free range chicken. Commercial broiler strains are not suitable for free range rearing and an alternative genotype is needed that will serve the South African market with the acceptable meat quality as a broiler. The objective of this study was to investigate the effect of production system (free range and intensive reared) and genotype (Broiler (COBB™), Ross 308 X Potchefstroom Koekoek hybrid and Potchefstroom Koekoek) on chicken meat quality. This was quantified on the morphological, physical (pH, colour, drip and cooking loss, water holding capacity and tenderness), chemical composition (moisture, protein, fat, ash contents and fatty acid profile), sensory quality and consumer preference of various chicken meat portions. The results of this study indicate that genotype had a more pronounced effect than production system on the morphological and growth properties of chicken meat, as well as on the sensory characteristics and consumer preference. The broilers had the best (P ≤ 0.05) feed conversion ratio (FCR), highest average daily gain (ADG) and European production efficiency factor (EPEF), followed by the Hybrid and then the Potchefstroom Koekoek. For each genotype, the free range chickens produced heavier (P ≤ 0.05) live weights than intensively reared chickens. Despite the poorer growth performance and efficiency of the medium growing Hybrid birds, they had less mortality and fewer leg disorders than the broiler. Additional to these factors, the Hybrid Free Range had higher thigh, drumstick and wing yields (P ≤ 0.05) than the broiler. When investigating the correlation between the chemical and sensory data, it was observed that the Hybrid scored significantly higher (P ≤ 0.05) in both flavour and aroma than the Broiler and Koekoek genotypes for both production systems. For colour, pH and polyunsaturated to saturated fatty acid ratio (PUFA:SFA), the effect of production system was more pronounced than the effect of genotype. Rearing chickens in a free range environment increased the PUFA:SFA ratio (P ≤ 0.05), making it beneficial to human health. Free range rearing resulted in lower muscle pHu (P ≤ 0.05), darker (L* value) (P ≤ 0.05), less red and yellow (a* and b* value) (P ≤ 0.05) chicken meat. It also influenced the chemical composition in different carcass portions; for example, a lower fat content in the thigh and higher protein in the breast of the Broiler. Correlation with the sensory results indicated that juiciness, tenderness, chicken aroma and chicken flavour are the main drivers of liking for consumer’s preference towards chicken meat. The consumers predominantly preferred the Hybrid (P ≤ 0.05) in a blind tasting session, but when information was given on the production system of a chicken product, the consumers lean more towards a free range reared product than an intensive reared product. This indicates that consumer perception plays an immense role in consumer decision making. Cluster analysis was also performed to ascertain whether the consumers differed in their degree of liking of the intrinsic character of the respective chicken samples. Three different clusters of consumers were identified: 1) Consumers that prefer free range reared chicken meat, 2) Consumers that prefer intensively reared chicken meat, 3) Consumers that prefer both free range and intensive reared chicken meat. In conclusion, the Hybrid seems to be a viable option for free range production systems in South Africa, without negatively affecting the overall quality of the meat or consumer acceptance. / AFRIKAANSE OPSOMMING: Moderne verbruikers is baie meer gesonheidsbewus en verkies meer natuurlik geproduseerde produkte soos vrylopende (free range) hoenders. Die kommersiële braaikuiken is nie geskik vir vrylopende produksie nie en `n ander genotipe word benodig wat die Suid-Afrikaanse mark sal kan voorsien met aanvaarbare vleiskwaliteit vergelykbaar met dié van die braaikuiken. Die doel van hierdie navorsing was om die effek van produksiestelsel (vrylopend en intensief) en genotipe (braaikuiken (COBB™), Potchefstroom Koekoek en Ross 308 X Potchefstroom Koekoek kruising) op die morfologiese, fisiese (pH, kleur, drip- en kookverlies, waterhouvermoë en taaiheid), chemiese samestelling (vog-, proteïen-, vet-, asinhoud en vetsuurprofiel), sensoriese kwaliteit en verbruikersaanvaarbaarheid van verskeie hoender vleis porsies te bepaal. Hierdie navorsing het getoon dat genotipe `n groter invloed gehad het as produksiestelsel op die groei en morfologiese eienskappe van die hoenders, asook op die sensoriese eienskappe en verbruikersaanvaarbaarheid. Die braaikuiken, gevolg deur die Ross X Koekoek kruising en dan die Koekoek, het die beste (P ≤ 0.05) voeromsetverhouding (FCR), gemiddelde daaglikse toename (GDT) en Europese produksie effektiwiteitsfaktor (EPEF) getoon. Vir elke genotipe het die vrylopende hoenders swaarder (P ≤ 0.05) lewende massa by slag getoon. Ten spyte daarvan dat die Ross X Koekoek kruising swakker groei en effektiwiteitsresultate getoon het, het hulle laer mortaliteite en minder been breuke en beserings as die braaikuiken gehad. Die Ross X Koekoek kruising wat vrylopend groot gemaak is, het ook swaarder dy, boud en vlerkie massa (P ≤ 0.05) as die braaikuiken getoon. Die navorsing het ook getoon dat kleur, pH en die poli-onversadigde tot versadigde vetsuur verhouding (PUFA:SFA) meer beïnvloed is deur die effek van produksiestelsel as genotipe. Die hoenders wat in ʼn vrylopende omgewing grootgemaak is se PUFA:SFA verhouding is hoër as dié van intensiewe boerdery, wat dit voordelig maak vir menslike gesondheid. Vrylopende hoenders se vleis is donkerder (L*) (P ≤ 0.05) en het ook laer rooi, geel (a* en b*) en pH (P ≤ 0.05) waardes getoon. Produksiestelsel effek het ook variërende chemiese waardes in verskillende karkas porsies tot gevolg gehad: ʼn laer vetinhoud is gevind in die dy en ʼn hoër proteïeninhoud in die borsies van die braaikuikens wat vrylopend grootgemaak is. Korrelasies met die sensoriese data het ook getoon dat sappigheid, taaiheid en hoendervleis geur die grootste dryfvere is in verbruikersaanvaarbaarheid. Tydens die verbruikerstoetse waar die verbruikers die gaar hoendervleis blind geproe het, het die verbruikers oor die algemeen meer gehou van die Ross X Koekoek kruising in vergelyking met die ander hoender genotipes (P ≤ 0.05), maar sodra inligting oor die verskillende produksiestelsels gegee is, het die verbruikers aangedui dat hulle hoenders wat vrylopend groot gemaak is, verkies. Dit dui daarop dat persepsies ʼn baie belangrike rol speel in die verbruiker se finale besluitnemingsproses. Statistiese segmentasietegnieke is ook op die data uitgevoer ten einde te bepaal of verbruikers in groepe verdeel kan word wat betref hul voorkeur van die sensoriese of intrinsieke eienskappe van die hoenderprodukte. Drie verskillende groepe is geïdentifiseer, nl. verbruikers wat 1) vrylopende hoender vleis verkies; 2) intensiewe hoender vleis verkies; 3) beide vrylopende en intensiewe hoender vleis verkies. In die lig van bogenoemde resultate wil dit voorkom of kruisteling tussen die gewone braaikuiken en die Potchefstroom Koekoek ʼn moontlike opsie is vir die Suid-Afrikaanse vryloop hoenderbedryf. Hierdeur word daar van vrylopende produksie stelsels gebruik gemaak sonder om die vleiskwaliteit of gebruikers aanvaarbaarheid negatief te beïnvloed.

Thesis (MScFoodSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Large volumes of high strength wastewater are generated annually by distilleries. Treatment of this wastewater is essential to increase its reuse potential. Anaerobic digestion (AD) has been widely applied as high strength wastewater treatment. Additionally, grain distillery wastewater (GDWW) is high in fats, oils and grease (FOG) which can cause problems during AD. Pre-treatment is therefore often required to make the AD process more efficient. The overall objective of this study was to investigate the operational efficiency of upflow anaerobic sludge blanket (UASB) reactors while treating GDWW as substrate. The first aim was to investigate the pre-treatment of the GDWW specifically for the removal of FOG by evaluating the effect of pH adaption, coagulant concentration and ozone (O3) dosages on the FOG reduction efficiency. Secondly, the effect of two different pre-treatments (only coagulant and coagulant and ozone) on the subsequent UASB treatment step was investigated. The pH of raw GDWW (pH 3.4) was adapted to three different pH values (5.0, 6.0, and 7.0) and the coagulant, aluminium chlorohydrate (ACH) (140 mg.L-1), was added. To make the process more economically viable, the lowering the coagulant concentration (to 100 mgACH.L-1) was also investigated. Optimal reductions for chemical oxygen demand (COD) (33.2% ± 4.93), total suspended solids (TSS) (91.9% ± 1.73) and FOG (84.1% ± 1.98) were, however, achieved at a higher coagulant concentration of 140 mgACH.L-1, and at a wastewater pH of 7.0. The effect of additional ozone treatment was also investigated. Maximum reductions for the ozone treatment were obtained at 100 mgO3.L-1 for COD (3.6% ± 4.08), and at 900 mgO3.L-1 for TSS (27.7% ± 5.58) and FOG (23.9% ± 1.83). The ozone treatment was most efficient for FOG reduction (in terms of mg FOG reduced per mg ozone) at 100 mgO3.L-1. An ozone dosage of 300 mgO3.L-1, was decided on based on economic feasibility, findings in literature on toxicity of ozone and the potential degradation of recalcitrant compounds at this dosage. The final pre-treatment thus included pH adaption to 7.0, coagulant dosage of 140 mgACH.L-1, and an ozone dosage of 300 mgO3.L-1. The second part of this study involved the operation of two 2 L laboratory scale UASB reactors for 277 days. The substrate of the first reactor contained GDWW that had only undergone coagulant pre-treatment (Rcontrol), while the substrate of the second UASB reactor consisted of GDWW that had undergone coagulant and ozone pre-treatment (Rozone). Both reactors treated the pre-treated GDWW successfully at ca. 9 kgCOD.m-3d-1. COD reductions of 96% for Rcontrol and 93% for Rozone, were achieved. FOG reductions (%) showed variations throughout the study and maximum reductions of 88% and 92% were achieved for Rcontrol and Rozone, respectively. The Rozone produced more biogas, but the methane content was similar for both reactors. The additional ozone pre-treatment did not show any added benefits to the reactor performance results. UASB granule washout in Rcontrol did, however, suggest possible toxicity of unsaturated fatty acids present in the non-ozonated substrate. The feasibility of FOG removal was shown as both reactors successfully treated pre-treated GDWW. Ozonation, after a coagulant dosage, which resulted in further reduction in the FOG content of the GDWW, is thus not essential to ensure the success of an anaerobic digestion step. Ozonation of the pre-treated GDWW could, however, be beneficial to gas production and the efficiency of a tertiary biological process. / AFRIKAANSE OPSOMMING: Groot volumes hoë-sterkte afloopwater word jaarliks deur distilleerderye opgelewer. Die behandeling van hierdie afloopwater is noodsaaklik om die hergebruiksmoontlikheid daarvan te verhoog. Die toepassing van anaërobiese vertering (AV) is wydverspreid in hoë-sterkte afloopwaterbehandeling. Graandistillerings-afloopwater (GDAW) is boonop hoog in vette, olies en ghries (VOG), wat probleme kan veroorsaak tydens AV. Voorbehandeling word dus dikwels verlang om die AV meer doeltreffend te maak. Die oorhoofse doelstelling van hierdie studie was om die doeltreffendheid van opvloei-anaërobieseslykkombers- (OAS-) reaktore wat GDAW as substraat behandel, te ondersoek. Die eerste mikpunt was om die voorbehandeling van die GDAW, te ondersoek vir die verwydering van VOG. Dit is uitgevoer deur die uitwerking van pH aanpassing, koagulantkonsentrasie en osoon(O3)dosis op VOG vermindering te evalueer. Tweedens is die uitwerking van twee verskillende voorbehandelings (slegs koagulant asook koagulant en osoonbehandeling) op die opvolgende OAS-behandelingsstap ondersoek. Die pH van rou GDAW (pH 3.4) is aangepas tot drie verskillende pH waardes (5.0, 6.0 en 7.0) en die koagulant, aluminium-chlorohidraat (ACH), is bygevoeg (140 mg.L-1). Om die proses meer ekonomies uitvoerbaar te maak is ‘n verlaagde koagulantkonsentrasie (verlaag tot 100 mgACH.L-1) ook ondersoek. Die optimale afnames vir chemiese suurstofvereiste (CSV) (33.2% ± 4.93), totale oplosbare vastestowwe (TOV) (91.9% ± 1.73) en VOG (84.1% ± 1.98) is egter bereik teen ‘n hoër koagulant konsentrasie van 140 mgACH.L-1, en teen ‘n afloopwater-pH van 7.0. Die uitwerking van ‘n bykomende osoonbehandeling is ook ondersoek. Die hoogste afnames tydens die osoonbehandeling is bereik teen 100 mgO3.L-1 vir CSV (3.6% ± 4.08), en teen 900 mgO3.L-1 vir TOV (27.7% ± 5.58) en VOG (23.9% ± 1.83). Die osoonbehandeling was mees doeltreffend vir VOG (in terme van mg VOG verwyder per mg osoon) teen 100 mgO3.L-1. Daar is besluit op ‘n van 300 mgO3.L-1, as gevolg van die ekonomiese uitvoerbaarheid, bevindinge in literatuur vir die toksisiteit van osoon, en die moontlike afbraak van moeilik-afbreekbare komponente teen hierdie dosis. Die finale voorbehandeling het dus bestaan uit ‘n aanpassing van die afloopwater-pH na 7.0, ‘n koagulantdosis van 140 mgACH.L-1, en ‘n osoondosis van 300 mgO3.L-1. Tydens die tweede gedeelte van hierdie studie is twee 2 L laboratoriumskaal OAS reaktore bedryf vir 277 dae. Die substraat van die eerste reaktor het GDAW bevat wat slegs ‘n koagulant-voorbehandeling ondergaan het (Rkontrole), terwyl die substraat van die tweede OAS-reaktor GDAW bevat het wat koagulant- en osoon-voorbehandeling ondergaan het (Rosoon). Beide reaktore het die voorbehandelde-GDAW suksesvol behandel teen ‘n organieseladingstempo van ca. 9 kgCSV.m-3d-1. Afnames in CSV van 96% vir Rkontrole en 93% vir Rosoon, is bereik. Tydens die studie is deurlopende wisseling in VOG verwydering (%) waargeneem, en die hoogste verwyderings wat bereik is, is onderskeidelik 88% en 92% vir Rkontrole en Rosoon. Die Rosoon het meer biogas geproduseer, maar die metaanpersentasie was soortgelyk vir beide reaktore. Die osoon-voorbehandeling het nie enige toegevoegde voordele getoon in die reaktorprestasie resultate nie. Die uitwas van die OAS-granules vir die Rkontrole het egter moontlike toksisiteit van onversadigdevetsure aangedui, wat moontlik teenwoordig kon wees in die nie-geösoneerde substraat. Die uitvoerbaarheid van VOG verwydering is getoon aangesien beide reaktore voorbehandelde GDAW suksesvol behandel het. Osonering, wat verdere afname in die VOG inhoud van GDAW teweeggebring het (na ‘n koagulant dosis), is dus nie noodsaaklik vir die suksesvolle verloop van ‘n anaërobiese-verteringsstap nie. Osonering van die voorbehandelde GDAW kan egter voordelig wees vir gasvorming, en kan ook verder die doeltreffendheid van ‘n tersiêre biologiese behandeling verhoog.

Thesis (MScFoodSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Knowledge of postharvest quality attributes of minimally processed packaged fruit is essential in order to establish the optimum shelf life period. The aim of this study was to investigate the effects of Passive-modified atmosphere packaging (MAP) on the quality of minimally processed pomegranate (cv. Bhagwa) arils and aril-sacs. These began by understanding the physiological processes i.e. respiration and transpiration rates of the whole fruit, arils and aril-sacs. The respiration rates (RR) of whole fruit, aril-sacs and arils were studied at 5, 10, 15 and 22°C, and comparisons were made among these fruit fractions. A high RR was observed in aril-sacs compared to whole fruit and arils across all storage temperatures. A 74.5% decrease in RR was observed when storage temperature was reduced from 22°C to 5°C. A significant increase in RR occurred from day 3 of storage across all fruit fractions and storage temperatures. The transpiration rates (TR) of arils and aril-sacs were studied at storage conditions of 5, 10 and 15°C and 76, 86 and 96% relative humidity (RH), and was found to increase with increase in temperature and decrease in relative humidity, with lowest TR occurring in fruit fractions stored at 5°C and 96% RH showing lower TR. Arils had high TR compared to aril-sacs, and this may be related to high surface area to volume ratio of exposed arils. The effects of modified atmosphere packaging and application of anti-browning agents on quality of arils and aril-sacs stored at 5°C were studied. Compared to clamshell packaging, Passive-MAP using POLYLID® 107 polyethylene (PE) polymeric film showed greater positive effects in maintaining the quality and extends the shelf life of the arils and aril-sacs. Furthermore, the anti-browning agents used controlled browning on the cut-surfaces of the peel of the aril-sacs and reduced microbial growth in both arils and aril-sacs. When the effects of MAP and anti-browning were combined, aril-sacs stored better than arils. These treatments extended the shelf life of aril-sacs to 12 days while arils lasted up to 9 days. The water vapour transmission rate (WVTR) of pomegranate fruit membrane was evaluated at cold storage (5°C, 90% RH) and room condition (18.7°C, 70% RH). A high WVTR occurred in membranes stored at room condition, compared to those stored at cold storage. Further studies are warranted to improve our understanding of the biophysical properties of pomegranate membranes in relation to possible exchange of water vapour and gases between the aril-sacs. In summary, the use of MAP in combination with anti-browning agents showed a high potential in maintaining the quality of pomegranate arils and aril-sacs and consequently increase their shelf-life. / AFRIKAANSE OPSOMMING: Kennis van naoes- gehalte-eienskappe van minimaal geprosesseerde verpakte vrugte is essensieel ten einde optimum rakleeftyd te bepaal. Die doel van hierdie studie was om die gevolge van passiewe gemodifiseerde atmosfeerverpakking (GAV) op die gehalte van arils en arilsakkies van minimaal geprosesseerde granaat (kv. Bhagwa) te ondersoek. ʼn Aanvang is gemaak deur die fisiologiese prosesse, m.a.w. respirasie- en transpirasietempo’s van die hele vrugte, arils en arilsakkies, te begryp. Die respirasietempo’s (RT) van hele vrugte, arilsakkies en arils is by 5, 10, 15 en 22°C bestudeer, en vergelykings is getref tussen hierdie vrugdele. ʼn Hoë RT is waargeneem by arilsakkies in vergelyking met hele vrugte en arils oor alle bergingstemperature heen. ʼn Afname van 74.5% RT is waargeneem toe bergingstemperatuur van 22°C na 5°C verminder is. ʼn Beduidende toename in RT het van dag 3 van berging af oor alle vrugdele en bergingstemperature heen voorgekom. Die transpirasietempo’s (TR) van arils en arilsakkies is by bergingstoestande van 5, 10 en 15°C en 76, 86 en 96% relatiewe humiditeit (RH) bestudeer, en daar is bevind dat dit verhoog met ’n toename in temperatuur en ʼn afname in relatiewe humiditeit, met die laagste TR wat voorkom by vrugdele geberg by 5°C en 96% RH wat dus laer TR toon. Arils het hoë TR gehad in vergelyking met arilsakkies, en dit kan verband hou met die verhouding van hoë oppervlakarea tot volume blootgestelde arils. Die gevolge van gemodifiseerde atmosfeerverpakking en aanwending van middels vir die voorkoming van verbruining op gehalte van arils en arilsakkies geberg teen 5°C is bestudeer. In vergelyking met verpakking in toeknipbakkies (clamshell packaging), het passiewe GAV waarby POLYLID® 107 poliëtileen- (PE) polimeriese film gebruik is, groter positiewe gevolge by die behoud van gehalte getoon, en die rakleeftyd van die arils en arilsakkies is verleng. Daarbenewens het die middels vir die voorkoming van verbruining beheerde verbruining op die sny-oppervlakke van die skil van die arilsakkies gebruik en mikrobiese groei in beide arils en arilsakkies verminder. Toe die gevolge van GAV en die voorkoming van verbruining gekombineer is, het arilsakkies beter as arils geberg. Hierdie behandelings het die rakleeftyd van arilsakkies tot 12 dae verleng terwyl arils tot 9 dae gehou het. Die waterdamptransmissiespoed (WDTS) van granaatvrugtemembraan is geëvalueer by koel berging (5°C, 90% RH) en kamertoestande (18.7°C, 70% RH). ʼn Hoë WDTS het voorgekom by membrane wat by kamertoestande geberg is in vergelyking met dié wat in koelbewaring geberg is. Verdere studies is geregverdig vir verbetering van ons begrip van die biofisiese eienskappe van granaatmembrane in verhouding met moontlike uitruiling van waterdamp en atmosfere tussen die arilsakkies.