No description available.

No description available.

Forage halophytes such as saltbush (Atriplex spp) are being widely used to revegetate Australian saline land and can also provide a medium quality fodder source. There is widespread anecdotal evidence that sheep grazing on saltbush are leaner, tastier and juicer. This thesis investigated the potential to produce a high quality carcass with improved eating quality from grazing sheep on saltbush on saline land. The first experimental chapter in this thesis details an animal house experiment investigating the carcass, eating and wool quality and physiological responses of sheep ingesting a 60:40 dried saltbush (Atriplex nummularia):barley grain (S+B), ration verses a 33:25:42 lupin grain:barley grain:oaten hay ration (Control, C) for 10 weeks prior to commercial slaughter (Chapter 4). Subsequently, two field experiments were conducted to examine the effects of grazing saltbush on saline land compared to dry senesced pasture on carcass and eating quality of lambs (Goomalling 2003) and hoggets (Wickepin 2004) (both chapter 6) for 14 weeks. Both chapters demonstrated that the ingestion of saltbush resulted in significantly less fat and in the 2 field experiments the ingestion of saltbush resulted in more lean on the carcass compared to sheep grazing a stubble/pasture (control) ration. These are positive findings for processors as costs of fat denudation are high so the lower the fat content and for farmers because less fat is deposited on the carcass per unit of liveweight gain. The decreased deposition of fat was attributed to the higher protein:energy ratio available for production, secondary compounds in saltbush and lower circulating insulin and higher growth hormone of the S+B fed sheep compared to the control fed sheep. Further work is needed to determine if these beneficial improvements in carcass composition can be achieved without compromising animal production. The long term grazing of saltbush did not result in commercially desirable hot carcass weights unless the sheep were supplemented with a high energy source such as barley. The low growth rates are attributed to a decreased availability of energy substrates, low feed intake and increased energy output of sheep fed high salt diets. The low energy intake of the S+B fed sheep also resulted in an a significantly lower percentage of unsaturated fat and unchanged levels of saturated fat in the fat depots compared to the C treatment. Consumer taste tests conducted on meat from experiments in both chapter 4 and 6 indicated no difference between the treatments for any of the eating quality traits assessed. This can be considered a positive result as sheep can be finished on saltbush without any detriment to eating quality. High vitamin E levels in the meat may have also prevented the development of rancid flavours and aroma. It can be speculated that saltbush does not impart beneficial flavour and aroma volatiles as previously thought; instead the high vitamin E levels inhibit off-flavour and aroma development compared to meat from sheep grazed on dry pasture. The long term ingestion of saltbush also resulted in significantly lower urine specific gravity (USG), muscle dry matter and higher urine weights suggesting that the saltbush fed sheep had a better hydration status compared to control fed sheep. However, this finding did not correspond with higher hot carcass weight or dressing percentages. The increases in muscle fluid content of the saltbush fed sheep were attributed to changes in body composition. The saltbush fed sheep had a higher lean and lower fat content which corresponded with a greater body fluid content as found in the animal house study. Under conditions where the body composition of sheep remains the same, the use of short term strategic feeding of components of saltbush was investigated (mimicked in the form of salt and betaine) to reduce dehydration and subsequent reductions in carcass weight and dressing percentages (Chapter 7). Salt and or betaine were fed for 1 week either prior to a 48 h period of water deprivation or prior to 48 h commercial slaughter process where water was available in lairage from 24-48 h. Under both scenarios the diets did not result in improved dressing percentages, hot carcass weights, muscle dry matter or muscle weights. The ingestion of high salt diet prior to slaughter, did increase fluid retention in the extracellular spaces prior to slaughter however by 48 h both groups were at a similar physiological and therefore similar hydration status. Therefore similar levels of fluid were present in the muscles and no difference in carcass weight or dressing percentage could be expected. An important observation from the second experiment was that the high salt group drunk more water than the low salt fed sheep but the low salt group consumed fluid in lairage also. The low salt fed sheep may have been encouraged to drink water after observing the frequent drinking patterns of the high salt group. This thesis has also shown that saltbush contains high levels of vitamin E (á-tocopherol) (193 mg/kg dry matter). As a result the concentration of á-tocopherol in plasma, liver and muscle of the saltbush fed sheep was elevated compared to those grazing dry pasture. The high muscle concentrations of vitamin E in the saltbush-grazed sheep resulted in improved meat colour stability. The high vitamin E levels did not influence the drip and cooking loss of the meat despite a decrease in the muscle dry matter of the meat. The browning of meat and increased drip loss results in large losses to the meat industry due to value deterioration at the supermarket. There is also great potential for the high vitamin E content in saltbush to be used for the prevention of nutritional myopathy instead of using expensive and labour intensive synthetic supplements. In conclusion, this thesis has provided an insight into the carcass and eating quality of sheep grazed on saltbush based saline pasture systems. The most significant findings were that

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Our study aimed to determine the preference of Western Cape consumers for the eating quality and appearance of pears. Identifying the main sensory drivers of liking and consumer groupings with similar preferences may allow the pear industry to target specific markets and increase local consumption, which is stagnating at relatively low levels. Our first trial included 9 European pear cultivars (Pyrus communis L.) and one Asian pear cultivar (P. pyrifolia (Burm.) Nak.). These were chosen to represent a wide range of characteristics in order to identify the main sensory drivers of liking and possible consumer groupings. The majority of the 421 consumers, irrespective of gender, ethnicity and age, preferred pears with a distinct pear flavour, a sweet taste, a fair amount of malic acid, soft, juicy flesh with melt character, and a yellow or pale green peel colour with a typical pear shape. Astringency, sourness and grittiness negatively affected consumer preference. None of the pears were mealy and therefore we could not assess this characteristic. Two consumer clusters with similar preferences for eating quality and also for appearance were identified. In terms of eating quality, group 1 (55% of consumers) indicated a liking for a wide range of cultivars with poorly defined likes and dislikes. Group 2 (45% of consumers), in contrast, had a high liking for the eating quality of a small selection of cultivars while disliking the rest. Based on the preferences for appearance, group 1 (61% of consumers) again indicated a liking for a wide range of cultivars. Group 2 (39% of consumers) scored the most familiar cultivars, viz. Bon Chretien and Packham’s Triumph, very high and the other cultivars much lower than group 1. The objective of our second study was to investigate consumer preference for firm, juicy pears compared to soft pears with a melt character and to identify which of ‘Forelle’, ‘Packham’s Triumph’ and ‘Abate Fetel’ is best suited to either option. Pears were harvested within the commercial harvest window (H1) (flesh firmness at 6- 6.8kg, 6.4-7kg and 6-6.8kg respectively) and again a month later (H2). H1 and H2 pears were ripened at room temperature (20 ºC) for seven or one day, respectively. More consumers (67%) correlated positively with melt character, juiciness, overall pear flavour and sweet taste. These characteristics were the most prominent in H1 ‘Packham’s Triumph’ pears while H2 fruit were much firmer, but lower in preferred flavour characteristics. There is, however, also a market for crisp and juicy pears as 33% of the consumers showed a preference for these characteristics. ‘Forelle’ and ‘Abate Fetel’ could both be suitable for this market. ‘Forelle’ was preferred firm, probably because H1 soft pears were more astringent and sour as well as less juicy than H2. There was no difference in preference between H1 and H2 in ‘Abate Fetel’. In conclusion, most Western Cape consumers prefer European pears with the characteristic soft, melting texture, but a third of consumers seem to like firm, juicy pears. Hence, there is opportunity to develop a market for tree-ripe and Asian pears, but marketing will be needed to overcome appearance preferences. / AFRIKAANSE OPSOMMING: Ons studie was daarop gemik om die voorkeur van Wes-Kaap verbruikers vir die eetkwaliteit en voorkoms van pere te bepaal. Die identifisering van die belangrikste sensoriese drywers van smaakvoorkeure en verbruikersgroepe met soortgelyke voorkeure kan die peerbedryf toelaat om spesifieke markte te teiken en plaaslike verbruik te verhoog, wat tans op relatief lae vlakke stagneer. Ons eerste proef het 9 Europese peer kultivars (Pyrus communis L.) en een Asiatiese peer kultivar (P. pyrifolia (Burm.) Nak.) ingesluit. Die kultivars is gekies om 'n wye verskeidenheid eienskappe te verteenwoordig sodat die belangrikste drywers van sensoriese smaakvoorkeure en moontlike verbruikersgroeperings geïdentifiseer kon word. Die meerderheid van die 421 verbruikers, ongeag geslag, etnisiteit en ouderdom, het pere met 'n duidelike peer geur, 'n soet smaak, 'n redelike hoeveelheid appelsuur, sagte en sappige tekstuur met n smeltkarakter, en 'n geel of liggroen skilkleur met 'n tipiese peer vorm verkies. Frankheid, hoë suurvlakke en grinterigheid het verbruikers voorkeur negatief beinvloed. Geen pere in ons studie was melerig nie en daarom kon ons nie hierdie eienskap evalueer nie. Twee verbruikersgroepe met soortgelyke voorkeure vir eetkwaliteit en peervoorkoms is geïdentifiseer. In terme van eetkwaliteit het groep 1 (55% van die verbruikers) voorkeur vir 'n wye verskeidenheid van kultivars aangedui. Groep 2 (45% van die verbruikers) daarteenoor het die eetkwaliteit van net 'n klein seleksie van kultivars verkies, terwyl hul ‘n afkeur getoon het vir die res. In terme van voorkoms, het groep 1 (61% van die verbruikers) weereens van 'n wye verskeidenheid kultivars gehou terwyl groep 2 (39% van die verbruikers) baie hoë punte aan die bekende Bon Chretien en Packham's Triumph kultivars toegeken het, maar die ander kultivars baie laer as groep 1 bepunt het. Die doel van ons tweede proef was om verbruikersvoorkeur vir ferm, sappige pere teenoor sagte pere met 'n smelt tekstuur te bepaal en tot watter mate 'Forelle', 'Packham's Triumph’ en ‘Abate Fetel' geskik is vir iedere opsie. Pere is tydens die kommersiële oesvenster (H1) (fermheid 6-6.8kg, 6.4-7kg en 6-6.8kg onderskeidelik) en weer 'n maand later (H2) geoes. H1 en H2 pere is teen kamertemperatuur (20 ºC) onderskeidelik vir sewe of een dag rypgemaak. Die meeste verbruikers (67%) se voorkeur korreleer positief met 'n smeltende tekstuur, sappigheid, peer geur en soet smaak. Hierdie eienskappe was die prominentste in H1 'Packham’s Triumph' pere terwyl H2 vrugte baie fermer, maar laer in voorkeur geureienskappe was. Daar is egter wel 'n mark vir ferm, sappige pere aangesien 33% van die verbruikers 'n voorkeur toon vir hierdie eienskappe. 'Forelle' en 'Abate Fetel' sou beide geskik kon wees vir hierdie mark. 'Forelle' is verkies as fermer peer, waarskynlik omdat H1 sagte pere meer frank, suurder sowel as minder sappig was. Daar was geen verskil in verbruikersvoorkeur tussen 'Abate Fetel’ se H1 en H2 pere nie. Ten slotte, die meeste verbruikers van die Wes-Kaap verkies die smaak van ryp Europese pere met hul karakteristieke sagte, smeltende tekstuur, maar 'n derde van die verbruikers hou wel van ferm, sappige pere. Daar is dus 'n geleentheid om die mark vir boomryp en Asiatiese pere te ontwikkel, maar bemarking sal nodig wees om die verbruikersvoorkeure vir voorkoms te oorkom.

For each of us, health is the most important thing, so that we can live a full life. How to proceed and what principles to follow when choosing foods, when there are many currently containing hazardous chemicals used in the food industry? Healthy eating and a healthy lifestyle are important. Cooking from basic ingredients and strengthening the immune system, from the childhood. However, it is never too late for adults. We can start anytime. I would like to show almost all aspects of quality eating, but also the other side, and the dangers of chemically modified food and the overall impact on quality of life. KEYWORDS Food, health, vegetables, fruit, vitamins, minerals, life, fementation, azo dyes

Tenderness, juiciness, colour and flavour are the most important meat quality attributes affecting the consumer acceptance. Maintaining the consistency of meat products by avoiding variable quality has become a major concern and great challenge to the meat industry. This in turn will also benefit meat end-users in the marketplace by having more tender meat. The present study was designed to evaluate the overall effects of pre-rigor infusion with kiwifruit juice, which contains the plant protease, actinidin, on lamb quality. A total of 18 lambs (12 months old) were divided into three treatment groups (6 lambs per each treatment). After exsanguination, lamb carcasses were infused (10% body weight) with fresh kiwifruit juice (Ac), water (W) and compared with a noninfusion treatment which acted as a control (C). Samples from different muscle/cuts (longissimus dorsi (LD) vs leg chops) at different post-mortem times (1 day post-mortem vs. 3 wks vacuum packaged storage at 2°C) and display time (0 to 6 days after the post-mortem storage) were analysed to monitor the changes on meat physical properties (e.g., tenderness, temperature, drip and cooking loss, colour), biochemical changes (pH, proteins and lipids) and volatile flavour compounds after the infusion treatments. The most tender meat (lowest shear force values) (P < 0.001) detected in the Ac carcasses post-mortem compared with C and W carcasses demonstrated that kiwifruit juice was a very powerful meat tenderizer, and could contribute to the meat tenderization process efficiently and effectively. Compared with C and W carcasses, the enhanced proteolytic activity (P = 0.002) resulting from the actinidin in kiwifruit juice in Ac carcasses caused degradation of the myofibrillar proteins and the appearance of new peptides during postmortem ageing. A slight positive effect in a*-value (redness) and decreased lipid oxidation, found in leg chops, was thought to be caused by the natural antioxidants in kiwifruit juice. Kiwifruit juice infused into the meat did not alter (P > 0.05) the volatile flavour compound profile indicating that the meat from Ac treated carcasses maintained its natural lamb flavour. No treatment differences were found for the temperature decline (P > 0.05) between the infused treatments and C. The higher rate of pH decline (P < 0.05) found in W carcasses might have contributed to the higher drip and cooking loss. The unbound water in meat might contribute to the higher L*-values (lightness) found in W carcasses. In summary, the proteolytic tenderizing infusion treatment using kiwifruit juice is a feasible approach for the commercial meat industry to increase profits, and also could satisfy the eating quality standards required by the consumers. In addition, tenderizing meat by using kiwifruit juice could also provide the kiwifruit processors an additional option for use of their product to gain a more profitable return.

Improved production and reduced consumption of beef is often highlighted as key aspects for tackling sustainability issues of the food system because the environmental impact of beef is ~100 times higher than plant-based foods. Both scientist and civil society organisations argue that eating “less but better” beef is important for sustainability. Better quality can encompass better eating quality as well as improved sustainability, but despite the two being very important for overall quality, very little research on interactions between them exists. No tools, applicable in Sweden, allowing for joint assessment have been developed. This study investigates the synergies and trade-offs between eating quality and environmental sustainability by using Swedish beef production as a case study. It reviews peer reviewed literature on factors that contribute to eating quality (flavour, tenderness and juiciness), and four factors that contribute to environmental sustainability (climate, biodiversity, feed/food competition and animal welfare). Based on the findings, an indicator-based sustainability assessment framework and a meat quality grading scheme differentiating Premium and Standard eating quality is developed, aimed to be practical tools for Swedish beef assessments. The study provides a systems-based understanding of synergies and trade-offs that may occur when “less but better” is presented as a strategy for tackling the environmental impact of beef. Results show that there are synergies between eating quality and biodiversity, animal welfare and with the right choices of feed, feed/food competition but with consequent trade-offs with climate impact. The discussion addresses the potential of enhanced eating quality to increase the profitability of Swedish beef production without consequent substantial negative impact on sustainability. The suggested methods have the potential to facilitate a shift from quantity- to quality-based consumption, but further empirical studies are required.

Total soluble solids (TSS) is a reliable indicator of melon eating quality, with a minimum standard of 10% recommended. The state of Australian melon production with respect to this quality criterion was considered within seasons, between growing districts and over seasons. It was concluded that improvement in agronomic practice and varietal selection is required to produce sweeter melons. The scientific literature addressing melon physiology and agronomy was summarised, as a background to the work that is required to improve melon production practices in Australia. The effect of source sink manipulation was assessed for commercially grown and glasshouse grown melon plants. The timing of fruit thinning, pollination scheduling, the application of a growth inhibitor and source biomass removal were assessed in relation to fruit growth and sugar accumulation. Results are interpreted against a model in which fruit rapidly increase in weight until about two weeks before harvest, with sugar accumulation continuing as fruit growth ceases. Thus treatment response is very dependant on timing of application. For example, fruit thinning at 25 days before harvest resulted in further fruit set and increased fruit weight but did not impact on fruit TSS (at 9.8%, control 9.3%), while thinning at 5 days before harvest resulted in a significant (Pless than 0.05) increase in fruit TSS (to 10.8%, control 9.3%) and no increase in fruit weight or number. A cost/ benefit analysis is presented, allowing an estimation of the increase in sale price required to sustain the implementation of fruit thinning. The effect of irrigation scheduling was also considered with respect to increasing melon yield and quality. To date, recommended practice has been to cause an irrigation deficit close to fruit harvest, with the intent of 'drying out' or 'stressing' the plant, to 'bring on' maturity and increase sugar accumulation. Irrigation trials showed that keeping plants stress-free close to harvest and during harvest, facilitated the production of sweeter fruit. The maintenance of a TSS grade standard using either batch based (destructive) sampling or (non-invasive) grading of individual fruit is discussed. On-line grading of individual fruit is possible using near infrared spectroscopy (NIR), but the applicability of the technique to melons has received little published attention. Tissue sampling strategy was optimised, in relation to the optical geometry used (in commercial operation in Australia), both in terms of the diameter and depth of sampled tissue. NIR calibration model performance was superior when based on the TSS of outer, rather than inner mesocarp tissue. However the linear relationship between outer and middle tissue TSS was strong (r2 = 0.8) in immature fruit, though less related in maturing fruit (r2 = 0.5). The effect of fruit storage (maturation/senescence) on calibration model performance was assessed. There was a negligible effect of fruit cold storage on calibration performance. Currently, the agronomist lacks a cost-effective tool to rapidly assess fruit TSS in the field. Design parameters for such a tool were established, and several optical front ends compared for rapid, though invasive, analysis. Further, for visualisation of the spatial distribution of tissue TSS within a melon fruit, a two-dimensional, or hyper-spectral NIR imaging system based on a low cost 8-bit charge coupled device (CCD) camera and filter arrangement, was designed and characterised.