Antibacterial Activity of the Secondary Product ‘Shibukiri Mizu’Produced During Azuki Paste Manufacturing

Abstract

‘Shibukiri mizu’ (SM) is the supernatant containing astringency components obtained from azuki beans that have been boiled in water for 6 min and then allowed to stand. Even though this supernatant is expected to contain many bioactive components, such as polyphenol glycosides, oligosaccharides and saponins, SM is currently disposed as a food-processing waste. In this study, we examined the antibacterial effects of SM on food-poisoning bacteria, plant pathogens, and plant growth-promoting bacteria. SM showed high antibacterial activity to Staphylococcus aureus 209P and Pseudomonas solanacearum MAFF 03-01418, and very minor activity to Pseudomonas fluorescens MAFF 01-06351. These results indicate that the food processing waste SM may be effectively re-utilized as an antibacterial material against food-poisoning bacteria and plant pathogens.