Rambutan (Nephelium lappaceum) peel extract: Antimicrobial and antioxidant activities and its application as a bioactive compound in whey protein isolate film

Abstract

This study focused on assessment of the bioactivities and characterization of rambutan peel extract (RPE) and the feasibility of RPE as a bioactive compound for antimicrobial and antioxidant applications in whey protein isolate (WPI)/cellulose nanocrystal film. The RPE inhibited against nine strains of pathogenic and food spoilage bacteria (Micrococcus luteus, Bacillus sp., Escherichia coli, Pseudomonas fluorescens, Salmonella typhimurium, Staphylococcus aureus, Enterococcus faecalis, Streptococcus sp. and Staphylococcus aureus). The extract also exhibited higher antioxidant activities than those of butylated hydroxytoluene (BHT) (via DPPH, ABTS and FRAP assays), α-tocopherol (via DPPH and ABTS assays) and butylated hydroxyanisole (BHA) (via hydroxyl radical and superoxide anion radical scavenging assays). The WPI/cellulose nanocrystal film containing 3% RPE exhibited moderate antimicrobial activity and strong antioxidant activity, which can be applied as a bioactive film for food packaging application.

Keywords

• rambutan peel extracts
• antimicrobial activity
• antioxidant activity
• whey protein isolate film
• cellulose nanocrystal