Antimicrobial activity of a crude peptide extract from lablab bean (Dolichos lablab) for semi-dried rice noodles shelf-life

This study provides an application of new, natural source of crude peptide extract from Lablab bean (CPL). Use of additive such as benzoate in the rice noodle industry is a common practice and has several beneficial effects on quality and shelf-life. However, the shelf-life of semi-dried rice noodles can be extended by crude peptide extract with acceptable quality when compared to other additives. This research aimed to extract CPL and determine its effect on the growth of microorganisms. The use of the CPL to extend the shelf-life of semi-dried rice noodles was compared with other natural extracts (chitosan and thymol) and benzoic acid. The CPL samples were extracted using 5% pepsin and incubated for up to 24 h. CPL at 200 mg/mL could be used as the growth inhibitor for Bacillus cereus but not for Staphylococcus aureus and Escherichia coli. It was found that noodles with CPL had the highest cooking loss (4.69) and lowest tensile strength (22.6 g.force). Overall-liking scores showed slightly liked (6.0 out of 9) and 68% of the consumers accepted the CPL-treated noodles. Shelf-life testing showed that CPL could extend the shelf-life of the noodles for 3 days than the control (1 day). Using 200 mg/mL of CPL could extend the shelf-life more than 3 times when compared to the control noodle (no additive). The CPL was nearly as effective as benzoic acid that could be kept for 3 days. Hedonic score in overall-liking showed a slightly like (6.2) for the noodles with CPL. This study suggests the application of adding CPL could be used as new natural additive and seems to be promising to apply in many food products such as pasta or sausages.