Development and Phytochemical Characterization of a Herbal Preservative from Tamarindus Indica and Ziziphus Abyssinica Herbs

Abstract

Food security issues are a major concern in the present day world, where people are coming up with all sought of methods of preserving food using conventional chemicals. Many of these chemicals are harmful to man and have been known to cause diseases. It then becomes necessary to device ways and means of preserving food using natural material such as herbs that are not known to pose a danger to the health of consumers. Many herbs with such preservative qualities have been identified, only that they have a bias to either antioxidant activity or antimicrobial activity. This study therefore, sought to blend two herbs, one of which exhibited dominant antioxidant activity and another antimicrobial activity. These herbs were then used to preserve pork sausages. The first part of the study determined the most efficient method of extraction by comparing soxhlet extraction with methanol as the solvent, cold extraction with methanol as the solvent and water extraction. To identify the active ingredients present in the extracts responsible for antioxidant and antimicrobial activity, profiling of the extract was undertaken using bioautographic, GC-MS and LC-QToF-MS methods. To identify the most effective blending ratio of the two herbs extracts AZA and MTI, herbs blends in the ratios of 1:3, 1:1, and 3:1 (MTI:AZA) were compared by subjecting them to TBARS, TVC and inhibition tests against test microorganisms E. coli. S. aureus, and candida albicans. The herbs extract blends were then applied in sausage preparations. Three sausage preparations having 1.8 kg each of pork were inoculated with 1.575 g, 3 g, and 6 g respectively of the herb extract blend 1:3 (MTI:AZA). The sausages were stored for five days at 4°C, and tested for development of rancidity (TBARS), protein degradation (PV), and microbial proliferation of TVC, E. coli, S. aureus and Candida albicans. The two herbs were identified as Ziziphus abyssinica (AZA) and Tarmarindus indica (MTI). It was also noted that water was the best solvent for extracting MTI, while the cold method of extraction using methanol as the solvent was the best for extracting AZA, 21 compounds were identified from the sample that exhibited antioxidant activity and 24 from the extract that exhibited antimicrobial activity against E. coli. S. aureus, and candida albicans. The extracts in the ratio 1:3 (MTI: AZA), was identified as the most effective herbs extract blend. In the TBARS test, both batches of sausages in whose preparation 1.575 g, and 3 g of extract were added and stored at 4°C were found to develop decay by the third day while the control and the sausages with 6g extract were still edible with no obnoxious smell on the fifth day. When the sensory analysis was done the sausages with 6 g herbal concentrate were rated acceptable. It was concluded that the blend of the two herbs is best suited to make a preservative that can substitute the use of synthetic preservatives in the market.