Extraction of Bio-Active Components from Fruit and Vegetable Processing Wastes: Using Grape Waste from the Wine Processing Industry as a Model
Abstract
Wastes generated from the fruit and vegetable processing industries cause significant disposal problems. A simple method to recover bio-active components from the waste would be economically advantageous. Therefore the objective of our research was to evaluate the effectiveness of different extraction methods in recovering antimicrobial components from processing wastes. Grape pomace from the wine making industry was used as a model to evaluate the extraction efficacy. Grape waste was ground under liquid nitrogen to a uniform particle size (3.6mm). Influence of process parameters such as solvents utilized (100% petroleum ether, 70% methanol, 50% acetone and 0.01% pectinase), solvent: waste ratio (2:1 or 4:1) and interaction time (1, 2, 4 and 8 h) were studied. Efficacy of the treatment parameters were studied based on antimicrobial testing of the extracts against common Gram negative and Gram positive food borne pathogens: Escherichia coli 0157:H7 and Staphylococcus aureus. Antimicrobial activity was measured based on time taken to increase absorbance of bacterial growth by 0.5U. Probit models were fit to the increase in absorbance (A 620) data and inverse predictions were used to identify time required for a 0.5U increase. The time taken to increase microbial concentrations by 0.5U was about 4.2 h for E.coli (control 3.6 h) and 3.9 h for S.aureus (control 3.3 h) with 50% acetone as a solvent. This is much higher than the time to reach equivalent microbial concentrations for the other solvents. Thus, it appears that this extract contains higher amounts of bioactive components. For both the organisms, significant inhibition (p<0.05) was obtained at lower interaction times and longer extraction times of 8 h were not significant. In conclusion, results indicated the optimum interaction times and extraction ratios for each solvent in recovering antimicrobial bioactive components from fruit and vegetable processing wastes was effective.
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- OSU Theses [15752]