Extension of shelf life of pork using spices (Plant Extracts: Xylopia aethiopica, Allium sativum and Piper nigrum).

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Date
2012
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Abstract
Microbial growth, changes in colour and pH are the major problems causing shortening of shelf life in meat and meat products. Chemicals and refrigerators could be used to preserve meat. However, the chemicals are polluting to the environment and have adverse effects on human health. The refrigerators cannot be used in places where there is no electricity. The objective of this project therefore was to find natural spices with antibacterial capacities that could be potentially used as natural preservatives in fresh pork and to compare the natural spices with artificial bacteriostatic agent (vinegar). The inhibitory effects of xylopia (Xylopia aethiopica), garlic (Allium sativum) and black pepper (Piper nigrum) extracts either alone or in combination and vinegar on the microbiological and chemical quality of fresh pork during storage at room temperature of 23oC were investigated. Qualitative analysis of aqueous extracts of the spices tested positive for the presence of phenols, alkaloid, glycoside, terpenoids, steroids, flavonoids, tannins and reducing sugars. The results showed that addition of the extracts either alone or in combinations significantly delayed the proliferation of aerobic plate counts or extended the shelf life of the product up to nine days versus one day only for control. During storage the pH and colour parameters of extract-treated pork samples changed slightly, in comparison with significant changes in the control. Overall, the sensory scores of mixture spice-treated samples was the best, followed by the vinegar-treated meat, xylopia-treated meat, garlic-treated meat, black-pepper treated meat. The study suggests that the tested extracts, especially xylopia and combinations of the spices have potential as natural preservatives to reduce microbial growth, maintain the chemical quality and extend the shelf life of pork during storage at room temperature.
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A Thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the Degree of Master of Science in Meat Science,
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