EVALUATION OF ANTIMICROBIAL AND ANTIOXIDANT POTENTIAL OF TEA AND CAROB EXTRACTS IN BUFFALO BUTTER

Abstract

The present study was carried out to evaluate the antimicrobial and antioxidant effects of black tea extract (BTE), green tea extract (GTE) and carob extract (CRE) in buffalo butter during storage at 4±1oC for 12 weeks and compare to synthetic phenolic compound butylated hydroxytoluene, (BHT). The antibacterial effect and minimal inhibitory concentration (MIC) of extract against Listeria monocytogenes were studied. The effectiveness of these extracts (0.025 – 0.05%) in butter made from pasteurized cream were evaluated by incubating (105 cfu/g) of Listeria monocytogenes. The GTE had completely inhibited (P≤0.05) the viability growth of Listeria monocytogenes during storage at 4±1oC (10 – 12 weeks) . During storage of butter made from unpasteurized cream, the population of lipolytic bacteria and mould&yeast markedly reduced (P≤0.05) by addition GTE (0.025 – 0.05%) compared to other treatments. Also, BHT (0.025%) and GTE had similar inhibitory effect on Staph. aureus. E. coli and total counts. The BTE and GTE had a most antioxidant effect on decreasing the acid value (AV), peroxide value (PV) and thiobarbituric acid value (TBA). While CRE had less effect. Organoleptically, butter with added BTE, GTE and CRE gained the highest acceptance until 8 weeks compared with BHT treatment and control sample. This research has demonstrated that the use of BTE and GTE as a natural antimicrobial and antioxidant is a promising means to provide additional safety and improve the quality of buffalo butter during storage.