Preservative activity of <I>Xylopia aethiopica</I> fruits bio-active fractions on fresh meat

Abstract

The availability of food and its accessibility to people has been an important concern in most developing countries where food preservation techniques have been very inadequate. In comparison with synthetic additives, natural preservatives may be more acceptable to consumers and regulatory agencies and also potentially of benefit to human health. Fractionation of crude ethanolic extract, phytochemical screenings of fractions, evaluation of antimicrobial and preservative activity were carried out. GC-MS on the most active fraction was also carried out. Phytochemical screening uncovered the presence of alkaloids, flavonoids, phenols, saponins, steroids, tannins and terpenoids. Antimicrobial activity results showed S. aureus with 18.33+0.33mm zone of inhibition and Aspergillus niger had least activity with 15.33+0.33mm at 4000µg/ml. The activity of the ethyl acetate fraction at highest concentration (4000µg/ml) against S. aureus was found to be not significant (p>0.05). Results of GC-MS analysis revealed the identity of the bio active compounds in the fraction such as phenols and terpinen-4-ol. The meat treated with 5% ethyl acetate fraction, recorded pH of 6.75 compared with negative control 7.74 while 5% vinegar (positive control) showed pH of 6.58 at 96 hours of storage. At 48 hours of storage, there were significant differences (P<0.05) in the pH of the treated meat with fractions, vinegar and untreated were observed. The sensory evaluation of the preserved meat by the judges showed meat treated with 5% vinegar had 50% likeness while meat treated with 5% ethyl acetate fraction recorded 30% likeness at 96 hours of storage.

Key words: Preservative, Phytochemical, bio active, fraction, Antimicrobial