Thesis (MScFoodSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The aim of this study was to investigate the effects of storage temperature and duration on the proximate composition, physico-chemical properties and selected bioactive components (vitamin C, anthocyanins and β-carotene) of arils from three pomegranate cultivars (‘Arakta’, ‘Bahgwa’ and ‘Ruby’). Pomegranates were hand-peeled and stored at three different temperatures (1°, 4° and 8°C) at 95% relative humidity (RH) for 14 days, with an additional day at ambient conditions (~21°C). Physico-chemical attributes, anthocyanins, ascorbic acid and proximate composition was measured on day 0, 7, 14 and 15. O2 consumption and CO2 production increased at elevated temperatures. No visual mould growth was detected in ‘Arakta’ and ‘Bahgwa’ arils after 14 days at 1°C 95% RH and after 7 days at 4°C 95% RH. Higher storage temperature negatively affected the proximate composition, physico-chemical attributes and bioactive components. The physico-chemical properties and selected bioactive components (anthocyanins, ascorbic acid, β-carotene) of pomegranate arils (‘Arakta’, ‘Bahgwa’ and ‘Ruby’) packed in three punnets made of polyethylene terephthalate (PET1 - clampshell; PET2 - tub and lid) or polypropylene (PP - tub and lid) material were studied for a period of 14 days at 5°C 95% RH. Packaging did not have a major effect on the physico-chemical and bioactive components of pomegranate arils, although PET2 had relatively stable headspace gas composition within the punnets. Storage duration caused a rise in pH and a decline in titratable acidity irrespective of packaging type. No visual mould growth was detected in ‘Arakta’ arils after 7 days irrespective of the type of packaging, while mould growth was detected in all ‘Ruby’ in all types of packaging. The earlier onset of visual microbial growth lead to a baseline microbiological study evaluating the effect of pre-storage water dipping of whole fruit on the microbiological quality of pomegranate arils stored for 8 days at 5°C 95% RH. Freshly harvested pomegranate fruit (‘Bahgwa’) were dipped in distilled water and air-dried (dipped fruit) or stored without postharvest dipping (dry fruit) at 7°C 95% RH for 15 weeks. Arils were extracted, packaged and stored at 5°C 95±8.34% RH for 8 days. Total viable aerobic mesophillic bacteria, yeasts and moulds, Escherichia coli and Staphylococcus aureus were enumerated. After 8 days at 5°C 95% RH no microbial growth was detected on arils from ‘dry fruit’, while ‘dipped fruit’ showed increased yeast and mould counts (4.74 log cfu.g-1) and total viable aerobic mesophillic bacteria count (3.73 log cfu.g-1). In conclusion storage temperature affects the nutritional quality of pomegranate arils and is best maintained at 1°C for 14 days or 4°C for 7 days at 95% RH. Current South African packaging used to market pomegranate arils don’t have a major effect on the nutritional quality of pomegranate arils, although the headspace gas composition was most stable in PET2 packaging. Pre-storage water dipping of whole pomegranates should be avoided as this could reduce the shelf life of extracted pomegranate arils. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die gevolge van bergingstemperatuur en -tydperk op die proksimale samestelling, fisies-chemiese eienskappe en geselekteerde bio-aktiewe komponente (vitamien C, antosianiene en β-karoteen) van granaatpitte van drie kultivars ('Arakta’, ‘Bahgwa’ en ‘Ruby’) te ondersoek. Granaatpitte is geberg by drie temperature (1°, 4° en 8°C) 95% RH vir 14 dae plus ‘n addisionele dag by kamertemperatuur (~21°C). Fisies-chemiese eienskappe, antosianiene, askorbiensuur en proksimale samestelling is gemeet op dag 0, 7, 14 en 15. Die granaatpitte se O2-verbruik en CO2-produksie het toegeneem by hoër bergingstemperature. Geen swamgroei was sigbaar na 7 dae by 1°C 95% RH sowel as 14 dae 4°C 95% RH. Hoër bergingstemperatuur het die proksimale samestelling, fisies-chemiese eienskappe en bio-aktiewe komponente negatief beïnvloed. Die fisies-chemiese eienskappe en geselekteerde bio-aktiewe komponente (antosianiene, askorbiensuur, β-karoteen) van granaatpitte ('Arakta’, ‘Bahgwa’ en ‘Ruby’) is verpak in drie bakkies vervaardig van polyethyleentereftalaat (PET1 – klamp-bakkie, PET2 – bakkie en deksel) of polipropileen (PP – bakkie en deksel) en bestudeer vir 14 dae by 5°C 95% RH. Heel granate was onderworpe aan 10-14 weke bergingstydperk by 7°C 95% RH voor die granate geskil en verpak is. Die bakkie tipe het nie 'n duidelike uitwerking op die fisies-chemiese en bio-aktiewe komponente van die granaatpitte gehad nie, alhoewel die gas samestelling in die kopspasie van PET2 bakkies relatief onveranderd gebly het. Gedurende die bergingstydperk het die pH gestyg en die titreerbare suur gedaal ongeag die bakkie tipe. Geen visuele swamgroei was sigbaar in ‘Arakta’ granaatpitte na 7 dae by 5°C 95% RH terwyl ‘Ruby’ granaatpitte wel swamgroei getoon het ongeag die bakkie tipe. Die vroeë aanvang van sigbare swamgroei het tot ‘n verdere mikrobiologiese basislynstudie gelei. Die uitwerking van voorbergingswaterdompeling van heel granate is geëvalueer op die mikrobiologiese gehalte van die granaatpitte wat gestoor was vir 8 dae by 5°C 95% RH. Vars ge-oesde ‘Bahgwa' granate is in water gedompel en gelugdroog (gedompelde granate) of glad nie in water gedompel nie (droë granate) en geberg by 7°C 95% RH vir 15 weke. Granate is ontpit, verpak en geberg by 5°C 95±8.34% RH vir 8 dae. Totale lewensvatbare aërobiese mesofilliese bakterieë, giste en swamme, Escherichia coli en Staphylococcus aureus telling is vervat. Granaatpitte van ‘droë granate’ was vry van enige mikrobiese groei na 8 dae. Die ‘gedompelde granate’ het ‘n toename in giste en swamme (4,74 log cfu.g-1) en totale lewensvatbare aërobiese mesofilliese bakterieë (3,73 log cfu.g-1) getoon. Hierdie studie maan dus teen waterdompeling van heel granate voor ‘n bergingsperiode van 10-15 weke. Ten slotte word die voedingswaarde van granaatpitte wel beïnvloed deur ‘n hoër bergingstemperatuur en sal die granaatpitte se gehalte behou word by 1°C vir 14 dae of 4°C vir 7 dae by 95% RH. Die voedingswaarde van granaatpitte word nie beïnvloed deur kommersiële verpakking wat tans in Suid-Afrika gebruik word om granaatpitte te adverteer nie, alhoewel PET2 bakkies se gas samestelling in die kopspasie onveranderd gebly het. Waterdompeling van heel granate voor ‘n verlengde bergingstydperk moet eerder vermy word aangesien dit die raklewe van granaatpitte verminder.

Bakgrund En kommun i mellansverige tillhandahåller önskekost på skolorna, enalternativ kost som kan förskrivas av skolsköterskor och individanpassas utifrån elevensbehov. Från kommunens sida såg man ett behov av att kartlägga rutinerna kring denna.Vi blev därför ombedda att leda studien i syfte att utforska eventuellt behov avförändring kring kosten.Syfte Att utforska skolsköterskors tankar och känslor kring sitt arbete med önskekost.Metod Kvalitativa intervjuer genomfördes med sex stycken av kommunensskolsköterskor med hjälp av en semistrukturerad intervjuguide. Intervjuerna spelades inmed en diktafon, därefter transkriberades datan ordagrant innan den analyserades medkvalitativ innehållsanalys.Resultat Kunskaperna om kost skiljde sig åt hos skolsköterskorna och det saknades enenhetlig bild över hur arbetet med önskekost såg ut på skolorna. Arbetet med vilka somfick önskekost, hur förskrivningen gick till, kulturskillnader mellan skolorna, nulägetsamt önskvärt läge var frågor som lyftes. Skolsköterskorna önskade behålla ansvaretöver önskekost. De såg också gärna en förändring av namnet. Fokus låg på attförskrivning skedde för att elever skulle uppnå skolmålen. Önskekost förskrevs intemed anledning av att eleven inte tyckte om någonting.Slutsats Önskekost förskrevs på grund av olika svårigheter med maten, men riktlinjerför när förskrivning skulle ske var oklara. Arbetet försvårades också av krav utifrån frånkommun, föräldar, lärare och elever. Det är viktigt att arbeta fram tydliga riktlinjer förvilka elever som ska beviljas önskekost och hur ordinationen ska följas upp.

The effects of processing (irradiation and heat treatment) and storage on the main nutrients (carbohydrates, proteins and lipids) of almonds (Prunus amyqdalus Batsch) have been investigated. Two varieties of Iranian almonds: P. amygdalus var. hard shelled, and P. amygdalus var. fragile, and one American variety, P. amygdalus var. semi-hard have been used in the present study. Variations between the nutrient composition of the different varieties were observed, and the range was between 93 and 132 mg/g for carbohydrates; 170 and 180 mg/g for proteins and 400 and 500 mg/g for lipids. The almonds were then subjected to the following three processes:1. A sample of shelled almonds was subjected to 2 Mrad irradiation using 60Co. Changes followed similar trends in the three almond varieties after irradiation. There were no significant losses in total available carbohydrates, total proteins and total lipids, whereas increases were observed in free amino acids, free sugars and free fatty acids. Storage of the irradiated almonds at 22°C for one year did not bring about any changes in total available carbohydrates, total protein and total lipids. However, there were changes in the individual free sugar fractions, while no changes were observed in free amino acids and in free fatty acids.2. Samples of shelled almonds were pre-soaked in 17% salt solution for 4 hours with slow agitation. After removing them from the solution, the salted nuts were transferred to a rotary drum and dried at 70°C for one hour, until the moisture taken up during the soaking treatment was removed. The temperature was then raised to 120°C within 30 minutes and roasted for 20 further minutes. Losses occurred in both carbohydrates and proteins, while the total lipid content remained unchanged after the above processing. Decreases were noted in free amino acids and in free sugars, but there were increases in free fatty acids. Storage at 22°C for one year resulted in no further losses of carbohydrates and proteins. Free amino acids increased, indicating some protein hydrolysis. A further increase in free fatty acids was observed. 3.A sample of shelled almonds was first roasted as described under (2) and then irradiated as described under (1); this being referred to as combined processing (dual treatment). The same three nutrients followed very similar trends to those found in roasted samples. So, on the whole, irradiation at 2 Mrad seems to preserve the nutrients of almonds much better than does roasting, especially during storage for one year.

Changes in plant cell wall composition caused by a variety of cooking and manufacturing processes have been investigated. These chemical changes have been compared with corresponding structural modifications which were assessed by light and electron microscopy. The different processing treatments have been applied to a single plant tissue, namely mung been seedlings, thus enabling comparisons to be made between the processes. Amino acid analysis was employed to assess changes in cell wall composition. The predominant amino acids in extensin, and isodityrosine, the critical cross-linking unit in this glycoprotein, were measured. Changes resulting from separate chemical extraction of pectin and glycoprotein wall components were also examined. An automated amino acid analysis method for isodityrosine has been established and a novel system for synthesising this dimer developed. The latter involves simple incubation of isolated cell walls with tyrosine, an arrangement which has achieved a six-fold increase in isodityrosine concentration. A reduction in the wall content of hydroxyproline and isodityrosine was observed in samples which had been stored in sulphite solution. It is suggested that this process may degrade pectin and glycoprotein. This idea is discussed with reference to the wall structure seen by microscopical examinations. The soluble extract resulting from boiling cell walls in dilute bicarbonate solution and the water-soluble pectin fraction were both found to contain significant quantities of isodityrosine. It is proposed that these two treatments may extract extensin glycopeptides or even cross-linked extensin oligomers from the wall. It is concluded that most of the processes damaged cell wall pectin to some extent while some also affected extensin. Results from the chemical fractionation experiments demonstrated that these two wall components tend to be co-extracted. This observation is discussed in relation to current models of cell wall structure.

Seasonal changes in the Persian orange (Citrus sinensis var. Sia-Varaz) and the effect of canning and storage on the juice were studied. The major factors under consideration were the physical characteristics: weight, size, volume of juice, colour of peel; and chemical characteristics: free sugars, vitamin C, free amino acids and lipid content. In order to determine the optimum state of maturity of the orange, samples were harvested at regular monthly intervals and analysed. 1. Throughout fruit development there was a continuous increase of juice, fruit size, and total soluble solids while total acidity decreased. These parameters were sufficiently different to enable the separation of the development cycle into three distinct phases: Cell division, Cell enlargement and Maturation of the fruit. Colour break from yellow to orange occurred between December and January but the oranges were assessed to be mature for harvesting by February and March. 2. Five sugars were identified: xylose, galactose, fructose, glucose and sucrose. Xylose soon disappeared while galactose was only found in minor quantities. Sucrose and reducing sugar content increased with fruit development. In the mature orange the ratio of suerose : glueose : fructose was very close to 2:1:1.3. While vitamin C content per 100 g pulp showed no significant change over the period of study the amount per orange pulp increased approximately four-fold. 4. Seventeen amino acids were identified. Increase in proline and arginine during December and January may be used as an indication of the onset of maturation. 5. Changes in lipid constituents were noted but, in general, no definite pattern could be established. The processing procedure involved heating the juice at 98°C for 30 seconds and then sealing in lacquered A1 cans. Analyses were carried out at two-monthly intervals. 6. Although total free sugars, vitamin C and colour of the juice were not affected by processing, significant increases in total free amino acids and lipids were noted.7. Storage of canned juice at 7°C for twelve months showed no significant effect on total free sugars, vitamin C, free amino acids and flavour. However, total lipid was significantly decreased after eight months. Storage of canned juice at 30°C brought about significant losses of total free sugars after twelve months, of vitamin C after two weeks, and of free amino acids after two months, and of total lipids after two months. The flavour of the juice, judged by a taste panel, had deteriorated significantly after one month's storage.

<p> Obesity, cardiovascular disease, and vulnerability among older adults highlight a critical need for a careful consideration of effective and preventive dietary interventions. Consuming flaxseed, along with a well-balanced diet, has been shown to significantly improve weight, waist circumference, blood pressure, serum lipids, plasma glucose levels, and inflammatory biomarkers. Although flaxseed exhibits anti-inflammatory and antioxidant properties, little is known regarding its consumer acceptability among older adults. The objective of this study was to investigate the acceptability of a flaxseed bagel in individuals 50 years and older using a 9-point Hedonic rating scale, Paired Preference test, and Food Action (FACT) rating scale. There were no significant differences between the control bagel (0% flaxseed) and flaxseed bagel (23%) in sensory attributes (appearance, color, flavor, aroma, texture, and overall acceptability) and FACT ratings in 20 participants (69.0 &plusmn; 6.3 years old). Age was significantly associated with the overall acceptability of the flaxseed bagel (<i>p</i> = .004) while gender showed no association with overall acceptability and FACT ratings in both bagels. Appearance, color, flavor, and texture were strongly correlated (<i>p</i> &lt; .01) to overall acceptability in both bagels. Further exploration of consumer acceptance of flaxseed products among older adults is needed; clinical trials may also shed light on potential health impacts of regular flax consumption.</p><p>

<p> Mauby Bark is commonly used to make a beverage believed to possess medicinal properties in the Caribbean. However, limited studies have substantiated these compounds. Therefore, the objectives of this research were to determine the polyphenolic content and antioxidant capacity of Mauby bark extracts boiled at 30, 45, and 60 minutes. The Total Flavonoid Content (TFC) ranged from 1.93 &plusmn; 0.17 CE/mL to 3.17 &plusmn; 0.11 mg CE/mL and the Total Phenolic Content (TPC) ranged from 2.10 mg &plusmn; 0.11 GAE/mL to 2.36 mg &plusmn; 0.07 GAE/mL. The 2,2 Diphenyl 1-Picrylhydrazyl (DPPH) scavenging activity ranged from 75 &plusmn; 4.02% to 83 &plusmn; 0.66% and the Ferric Reducing Antioxidant Power (FRAP) values ranged from 6.29 &plusmn; 0.84 to 6.90 &plusmn; 1.54 mM FeSO₄ equivalents/0.2 mL. Although polyphenolic content at 30 minutes was greater than 60 minutes for TFC (<i>p</i> &lt; 0.001) and TPC (<i>p</i> = 0.002), the scavenging activity was greater at 60 minutes than 30 minutes (<i>p</i> = 0.014) while antioxidant power was not affected by time (<i>p</i> = 0.736). In summary, 60 minutes was observed to provide the greatest antioxidant benefits in Mauby bark extracts for consumers.</p><p>

Because of their health benefits, probiotics are a significant part of the functional food industry. Spray drying is reported as the most common method used in the food industry to encapsulate probiotics. The objectives of this study were to investigate the effects of protective agents on the viability of lactobacilli after spray drying and during storage at different conditions and to evaluate spray drying conditions to produce these probiotic powders. Lactobacillus plantarum NRRL B-4496 (LP) and Lactobacillus acidophilus NRRL B-4495 (LA) were separately grown (~109 CFU/ml) and suspended in a 200 g/L solution of high maize starch (HM); maltodextrin (MD); or gum arabic (GA). The solutions were separately spray dried at 140 °C to obtain LP and LA-powders: LPHM, LPMD, LPGA, LAHM, LAMD, and LAGA. The powders were separately placed in aluminum bags and separately packed under 97% and 10% vacuum. The powders were stored at refrigerated (4 °C) or at room (23 °C) temperature for 60 days. Physicochemical properties, energy and mass balances, and cell viability during storage were determined. Triplicate experiments were conducted and data were statistically analyzed (α=0.05). The actual production rate of powders ranged from 0.091 to 0.105 (kg dry solids/h). The energy used during spray drying was not significantly different for any of the powders. After 60 days, LPHM powders packed under 10% and 97% vacuum and stored at 4 °C had significantly higher cell viability than the other powder samples. The study demonstrated significantly improved on the viability of LP at 10% vacuum stored at refrigerated temperature for the HM treatment compared to those treated with MD and GA. The data obtained showed that high maize starch can be used as a protective agent to maintain the viability of L. plantarum powder at recommended levels for up to 60 days of storage.

<p> More than 500 million people are affected by obesity worldwide and in 2015 no state in the United States had a prevalence of obesity less than 20%. It is well-documented that obesity is linked with an increased risk of chronic diseases such as: metabolic syndrome, hypertension, insulin resistance, diabetes, arterial hypertension, and dyslipidemia. A weight management intervention that is affordable, convenient, appealing, and effective is needed in order to target this epidemic. In an effort to provide supplemental resources needed by weight management programs, the <i>Telehealth Nutrition Manual for An Online Intensive Behavioral Weight Management Program</i> was created. The purpose of this project was to create a nutrition manual for those seeking weight loss through online program interventions. The manual includes guidance on appropriate caloric intake, monitoring biochemical markers, strategies for behavior change, and a variety of dietary approaches within a flexible meal plan. Recommendations for future nutrition manuals are provided. </p>

In this project the selective conversion of glucose to ethanol from glucose/fructose mixtures was investigated. The process was carried out using a mutant of Saccharomyces cerevisiae, batchwise, continuously with immobilized cells and semicontinuously. The kinetic behaviour of S. cerevisiae ATCC 36859 was studied using batch fermentation data. The growth of the yeast is inhibited equally by glucose and fructose, even though fructose is not consumed by the yeast. Fermentation models were formulated in this work. These models include terms which account for the inhibition of growth, glucose consumption and ethanol production by the carbohydrate and ethanol. The models predict that the growth rate of the yeast will be zero if the medium contains either 488 g/L total carbohydrates of 62 g/L ethanol. Batch tests were carried out with hydrolyzed Jerusalem artichoke juice and High Fructose Corn Syrup. An ethanol productivity of 21 g/Lh was attained in a batch process using an initial biomass concentration of 94 g/L. It was found though that this process suffered from the inhibitory effects of high total carbohydrate concentrations, therefore products containing high fructose concentrations were produced with lower ethanol productivities. In addition, reuse of the biomass resulted in a reduction of 40% in its activity. The cells were immobilized in calcium alginate beads and placed in a tubular reactor. In this form they were used for more than 1000 hours without a loss of activity. A syrup containing fructose as 99% of the reducing sugars was produced from synthetic as well as from food grade glucose/fructose mixtures. A maximum ethanol productivity of 13 g/Lh was attained. A product containing 76 g/L ethanol was also produced in this process. The productivity of the reactor was reduced as the total carbohydrate concentration was increased, therefore products with a high fructose concentration ($>$150 g/L) could not be formed without a significant drop in the productivity using the immobilized cells. The inhibitory effects of high total carbohydrate concentrations were reduced by using a fed batch process. In this scheme, 42 High Fructose Corn Syrup was used with and without added nutrients as the feed solution; sterilization of the syrup was not necessary due to its high solids concentration. The syrup was continuously fed to a bioreactor, the glucose was converted to ethanol while the fructose accumulated. A syrup containing 257 g/L fructose and 68 g/L ethanol was produced in this process. The product formed in the process was purified with activated carbon and ion-exchange resin. A clear and colourless fructose syrup that visibly resembled HFCS was produced. The ethanol in the product allowed for storage of the product for long periods of time before its further treatment. (Abstract shortened by UMI.)