Browsing by Author "Neethling, Jeannine"

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    Factors influencing the flavour of the meat derived from South African game species
    (Stellenbosch : Stellenbosch University, 2016-03) Neethling, Jeannine; Hoffman, Louwrens C.; Muller, M.; Stellenbosch University. Faculty of Agrisciences. Dept. of Food Science.
    ENGLISH ABSTRACT: In South Africa, wild and free-living animal species that are dependent on the natural vegetation present in their habitat as food source, are referred to as ‘game species’. Game species are utilised for live animal sales, trophy hunting, non-trophy recreational hunting and game meat production. The latter is of economic importance, as the export of game meat is a very lucrative industry for South Africa. However, only small quantities of fresh game meat is sold locally in South Africa, which is attributable to a lack of scientific information on the chemical composition and sensory quality of game meat that is required to enable proper marketing of game meat products. Game meat is derived from female and male animals of various species, located throughout southern Africa. However, differences in the dietary regimes of game species between farm locations, in addition to species and gender differences could influence the composition and sensory quality of game meat. Differences in the fatty acid content and volatile compound profile could influence the aroma and flavour of meat, yet no research exists that has established the volatile compound profile of South African game meat. The volatile compound profile of the longissimus thoracis et lumborum muscle of commonly consumed game species (springbok, Antidorcas marsupialis; blesbok, Damaliscus pygargus phillipsi; gemsbok, Oryx gazella; impala, Aepyceros melampus; red hartebeest, Alcelaphus caama; and kudu, Tragelaphus strepsiceros) from various farm locations was mainly lipid-derived, containing compounds such as aldehydes, alcohols and 2-pentylfuran. Farm location and gender had a significant influence on the fatty acid content and volatile compound profile of springbok and blesbok meat. Furthermore, the fatty acid content and volatile compound profile of game meat differed significantly between the six species, while gender differences were more species-specific. Descriptive sensory analysis was used to establish the sensory profile of game meat in this study. The latter, in addition to physical measurements (thaw and cooking loss percentage, ultimate pH and Warner-Bratzler shear force) and the proximate composition (moisture, protein, intramuscular lipid and ash) were used to establish the sensory quality of game meat derived from different farm locations, species and genders. Farm location had a significant influence on the sensory quality of springbok meat, while this was not evident for blesbok meat. Selected physical, proximate and sensory attributes differed significantly between the six game species, however, when conducting multivariate analyses using all of the sensory attributes as variables it is clear that springbok meat illustrated a prominent gamey sensory profile and thus associated with a different set of sensory attributes than the other five game species. This study also indicated that gender differences in the sensory quality of game meat are more species-specific. It is therefore recommended that the meat industry should take farm location (for springbok and not blesbok) and species into account during the marketing of game meat. As the influence of gender on the sensory profile of the game meat from the selected species in this study was of minor importance, it is recommended that this factor not be considered during the marketing of game meat derived from these six game species. However, the magnitude of the influence of species and gender on the sensory quality of game meat could change when other factors such as season and farm location come into play
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    Impact of season on the composition and quality of male and female blesbok (Damaliscus pygargus phillipsi) muscles
    (Stellenbosch : Stellenbosch University, 2012-12) Neethling, Jeannine; Hoffman, Louwrens C.; Britz, T. J.; Stellenbosch University. Faculty of AgriSciences. Dept. of Food Science.
    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.
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    Polyunsaturated fatty acid, volatile and sensory profiles of beef from steers fed citrus pulp or grape pomace
    (Elsevier, 2020-11-28) Tayengwa, Tawanda; Chikwanha, Obert C.; Neethling, Jeannine; Dugan, Michael E. R.; Mutsvangwa, Timothy; Mapiye, Cletos
    The present study compared the effects of feeding dried grape pomace (DGP) or citrus pulp (DCP) at 150 g/kg dry matter compared to a control diet on major polyunsaturated fatty acids (PUFA), volatile and sensory profiles of beef. Feeding DGP or DCP diets to Angus steers for 90 d increased the proportions of C18:2n-6, C20:4n-6, C18:3n-3, total conjugated linoleic acid (CLA), n-3 and n-6 PUFA in muscle. Control-fed beef had greater concentrations of C18:1n-9, total aldehydes, ketones, and alcohols compared to DCP and DGP. Feeding DGP and DCP diets produced less tender beef than control. Overall, finishing steers on diets containing DGP or DCP compared to control increased proportions of total CLA, n-3 and n-6 PUFA, and reduced concentrations of aldehydes, ketones, and alcohols, but did not affect beef sensory attributes except for a slight reduction in tenderness.