Antioxidant and antibacterial properties of a few local honeys

Ng , Xiao Wen (2005) Antioxidant and antibacterial properties of a few local honeys. Universiti Malaysia Sabah. (Unpublished)

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Abstract

The objective of this study is to determine the antioxidant activities and the antibacterial properties of a few local honeys. Thirteen honey samples consisted of wild and cultured honeys were selected from 5 different locations to compare their antioxidative and inhibitory effects against 2 foodborne pathogens, Listeria monocytogenes L55 and Salmonella typhimurium S1000, and 1 food spoilage bacteria, Pseudomonas aeruginosa ATCC 27853. The variations in the physicochemical properties of honey samples such as moisture content, pH, °Brix, free acidity, lactone content, total acidity, viscosity and color were depend on the geographical and botanical origins of the honeys. The Cameron Highlands honeys had the highest mean value in the yields of total phenolic extracts (2.19 %), flavonoids extracts (0.55 %) and phenolic esters extracts (0.27 %) compared to samples from other locations. The total phenolic content of the honeys were determined and the levels of content varied considerably with the highest value obtained by sample CH2 (2.87 mg/g extract) from Cameron Highlands. The antioxidant properties of the honeys, namely the water soluble antioxidant content, radical scavenging activity and total antioxidant activity were also evaluated by using l,l-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and β-carotene bleaching method. Among all the samples collected, honeys from Cameron Highlands which possessed the highest mean of phenolic contents (2.28 mg/100 g honey), exhibited the strongest total antioxidant activity (79. 06 %) and DPPH radical scavenging activity (79.85 %). In addition, the total phenolic contents of all the samples were positively correlated with the radical scavenging activity (r=0.770, p<0.01), total antioxidant activity (r=0.749, p<0.01) and water soluble antioxidant content (r=0.747, p<0.01), indicating that the antioxidant capacities were attributed to the phenolic contents in the honeys. Preliminary screening of the peroxide and non-peroxide antibacterial activities of honeys based on disc diffusion assay showed that the development of the inhibition zone depends on the type and concentration of honey, as well as the test pathogen. Residual antibacterial properties were still observed after the removal of hydrogen peroxide by using catalase, which are claimed to exert antimicrobial property in honey. All the catalase treated and non-catalase treated 25 % honey solutions from Cameron Highlands exhibited strong antibacterial activity against the test bacteria by forming inhibitory zones of more than 8 mm. However, the 20 % honey solutions of the same location only showed moderate antibacterial activity (inhibitory zone <8 mm) against all the test bacteria. The screening test for the honey extracts (total phenolic, flavonoids and phenolic esters extracts) indicated that the CH2 total phenolic extract exhibited the strongest activity among all the extracts with the inhibitory zones of 12.35 mm, 10.37 mm and 9.48 mm against L. monocytogenes, S. typhimurium and P. aeruginosa, respectively. The total phenolic extract of the CH1 and CH2 from Cameron Highlands had the lowest MBC of 56.25 mg/m/ against L. monocytogenes. However, longer decimal reduction times were required to inhibit the same bacteria (>8 h) compared to the KE2 total phenolic extracts with MBC 300 mg/ml which were able to reduce 1 log cycle of L. monocytogenes in only 2.74 h. This indicated that the KE2 total phenolic extract possessed fast acting antimicrobial agent In conclusion, the Malaysian honeys and their extracts have the potential to be used in food industries as novel natural preservatives due to their antioxidative and antibacterial properties.

Item Type: Academic Exercise
Uncontrolled Keywords: Honeybees, Bee Colony, Production, Composition of Honey, Physicochemical, Antimicrobial Properties, Effects in Health
Subjects: T Technology > TX Home economics > Nutrition. Foods and food supply
Divisions: SCHOOL > School of Food Science and Nutrition
Depositing User: MDM SITI AZIZAH IDRIS
Date Deposited: 18 Sep 2013 03:35
Last Modified: 18 Sep 2013 03:35
URI: http://eprints.ums.edu.my/id/eprint/6992

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