Prebiotic potential of rambutan peel with cardamom oil and its application to extend the shelf-life of plant-base rice milk

Abstract

This study explores the impact of cardamom oil vapor on the structure, functional performance, and prebiotic properties of rambutan peel, along with its application in plant-based rice milk. The prebiotic potential of rambutan peel, both with and without cardamom oil at 30 μl, was investigated on probiotics (Lactobacillus plantarum and Bifidobacterium longum) and their effectiveness against gut pathogenic bacteria (Escherichia coli, Listeria monocytogenes, and Salmonella Typhimurium). The effects of treated rambutan peel on the shelf-life and quality of plant-based rice milk were studied at 4 °C for 20 days. Rambutan peel exhibited a high content of dietary fiber, with approximately 33 % insoluble dietary fibers and 15 % soluble fibers. After treatment of the peel with cardamom oil, a larger area and bigger pore size on rambutan peel were observed, along with a higher oil capacity content, phenolic color pigments, and antioxidant activity. Rambutan peel with cardamom oil increased the relative abundances of Lactobacillus and Bifidobacterium while decreasing the relative abundances of all the gut pathogens in this study. The treated rambutan peel formed a gelling structure in the texture of rice milk with higher viscosity. Additionally, the shelf-life of rice milk containing treated rambutan peel was found to be at least 20 days without the growth of pathogenic bacteria, compared to the control (<5 days). These findings highlight the potential application of rambutan peel with cardamom oil as a novel prebiotic active ingredient in functional foods for the first time, producing a safe, functional product that enhances the utilization of waste fruit.