Sensory evaluation and antimicrobial activity of snack bar from black soybean and black rice containing anthocyanins

Abstract

Snack bars made from black soybean and black rice could be used as a food product to complement the energy and nutrients needs. Both have anthocyanins content in black soybean and black rice as well as the potential as an antimicrobial agent. The purpose of this study was to obtain an optimal formula, evaluate the sensory acceptance, analyze the total monomeric anthocyanin content of the snack bars, and compare the growth of probiotic and pathogenic bacteria in anthocyanins crude extracts from the snack bars. The production of snack bars was done by using three variations of main ingredients, including 30% of black soybean + 70% of black rice (formula 1), 50% of black soybean + 50% of black rice (formula 2), and 70% of black soybean + 30% of black rice (formula 3). The results performed that consumers acceptance for formulas 2 and 3 was not significantly different (P > 0.05), but significantly higher (P < 0.05) than formula 1. Total monomeric anthocyanin content analyzed by the pH differential method in these three snack bars formulas had no significant difference (P > 0.05). The growth analysis of probiotic and pathogenic bacteria showed that the percentage of growth inhibition of Escherichia coli and Salmonella enterica serovar Typhi bacteria was significantly higher (P = 0.00) compared to Lactobacillus acidophilus. Also, formulas 1 and 2 could significantly inhibit E. coli and S. enterica ser. Typhi bacteria (P = 0.00) compared to formula 3. It could be concluded that formula 2 showed the best snack bar based on sensory evaluation and pathogenic bacteria inhibition assay.