ARS | Publication request: Evaluation of the Antimicrobial Capacity and Active Compounds of Extracts from Different Sections of Various Muscadine Cultivars

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: October 18, 2009
Publication Date: April 15, 2010
Citation: Chen, W., Taejo, K., Silva, J., Marshall, D.A., Stringer, S.J. 2010. Evaluation of the Antimicrobial Capacity and Active Compounds of Extracts from Different Sections of Various Muscadine Cultivars. HortScience. 45:497.

Technical Abstract: Muscadine (Vitis rotundifolia Michx.) grapes are rich in phenolics and other bioactive compounds. These compounds possess antioxidant and antimicrobial properties. The objectives of this research were to determine which cultivars and what parts of the grape (concentrating on skin and seeds, the richest in antioxidants) were higher in phenolics acids and had higher antimicrobial activity. Hot water-soluble muscadine extracts from skin and seed sections of each muscadine cultivar were prepared for investigation. Phenolic and polar compounds of each of the extracts was determined by HPLC. A cocktail of three stains of Eschericia coli O157:H7 were used to discern the antimicrobial capacity of each sample by the disc diffusion test. For the skin part, the samples from some varieties had strong antimicrobial activities, which can reduce an initial population (~5log CFU/ml) of the cocktail to non-detectable levels (< 10 CFU/ml). However, regardless of other factors, the samples from some other varieties had no significant antimicrobial capacity (<0.06 log Reduction). The concentrations of main active organic compounds were different among cultivars, correlating to results in the antimicrobial tests. Tartaric acid concentration in skins, for example, was 9645.2 ppm (Nesbit), which also showed a high log reduction of 4.92, and was low in ‘Sweet Jenny' 3764.2 ppm which showed no antimicrobial activity. Similar results were seen with the seed sections. The results revealed that different amounts of bioactive compounds existed differently in different sections of various cultivars which were suggested to be interrelated to their different antimicrobial results.