Browsing by Author "Henn, Angelique"

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    Meat quality characteristics of the plains zebra (Equus quagga)
    (Stellenbosch : Stellenbosch University, 2020-03) Henn, Angelique; Hoffman, Louwrens C.; Lambrechts, Helet ; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science.
    ENGLISH ABSTRACT: This study presents the first available baseline information on the carcass contribution, physical meat parameters, chemical and mineral composition of plains zebra meat, and sensory profile and optimum ageing period of seven selected plains zebra (Equus quagga) muscles [Longissimus thoracis et lumborum (LTL), semimembranosus (SM), biceps femoris (BF), semitendinosus (ST), infraspinatus (IS), supraspinatus (SS), and psoas major (PM)]. The muscles were obtained from animals cropped during a wet winter season (n = 8) and a dry summer season (n = 12) in the Western Cape Province of South Africa. The average undressed carcass weight of the winter-harvested stallions and summer-harvested stallions were 324.4 ± 5.55 kg and 291.50 ± 11.65 kg, respectively. Average cold carcass weight reported for the winter- and summer-harvested groups were 188.3 ± 4.03 kg and 164.5 ± 5.53 kg, respectively. The warm and cold dressing percentages were numerically higher for the winter-harvested animals (59.5 ± 0.55 % and 58.0 ± 0.60 %, respectively) than for the summer-harvested animals (58.1 ± 0.68 % and 56.60 ± 0.70 %, respectively). Harvest season did not influence the proportional contribution of the LTL, SM, BF, ST, IS, SS and PM to the cold carcass weight. A considerable amount of internal offal (21.8 to 22.5 % of the undressed cold carcass weight) has the potential to be used as a low-cost protein source. All the physical parameters (pHu, drip loss, cooking loss, shear force and colour coordinates) differed between the muscles and seasons respectively, except for the CIE a* and chroma. The ultimate pH (pHu) of all the muscles fell within the biological normal range and was not classified as dark firm and dry meat. Most of the physical measurements (pHu, drip loss, cooking loss and colour coordinates) were comparable to values characteristic to red meat, the exception being the high shear force values for samples obtained from both seasons. Meat samples from the winter-harvest animals were intermediate in terms of toughness, compared to summer-harvest samples that were characterised as tough. The ST and SS of the winter-harvested animals, and the IS of the summer-harvested animals, were intermediate in terms of toughness. The remainder of the respective muscles obtained from both groups had shear force values representative of tough meat. The CIE colour of the meat samples obtained from both groups corresponded to the intermediate range associated with game meat. The selected muscles differed significantly in terms of moisture, protein, and intramuscular fat contents. The muscle protein content was the only component influenced by season of harvest, with winter-harvested samples having a higher protein content when compared to the summer-harvested samples (21.8 ± 0.18 g/100g vs. 20.7 ± 0.12 g/100g). Season-muscle interactions were reported for the intramuscular fat and ash content, while strong negative correlations were reported for pooled moisture and protein. The primary macro- and micro-minerals present in the LTL, SM, BF, liver, and rib included potassium, phosphorous, sodium and magnesium together with iron, zinc, copper, selenium (except in the rib), manganese and strontium. Muscle type influenced the sodium, iron, copper, manganese, and strontium levels. The significant differences for the proximate and mineral composition observed for each of the main effects were marginal, and therefore it is debatable whether it is of biological consequence in terms of human health when consumed. The sensory profile of plains zebra meat can be characterised as game-like, beef-like, sweet-associated, and herbaceous aromas and flavours. The LTL, SM and BF muscles differed significantly in terms of sensory profile, and fatty acid content, with the BF having a distinct sensory profile as well as a higher fatty acid content. An ageing trial was conducted to determine the optimum ageing period needed to reach the maximum meat tenderness for the LTL, SM and BF muscles. An improved bloomed surface colour and maximum tenderness was achieved at 14 days and 20 days post-mortem for summer-harvested samples, respectively. Colour stability of the muscles were high as no visual discolouration was observed up to day 32 of post-mortem ageing. Findings from this study will contribute meaningfully to the establishment of meat production potential of plains zebra under controlled farming conditions, thus investigating the potential of this species to contribute to food security in South Africa.