The high potential of a red-light submerged fermentation technique in the biofunctionality improvement of rambutan extracts

Abstract

Purpose Rambutan (Nephelium lappaceum), a ubiquitous fruit in Southeastern Asia, was rich in vitamins and phytochemicals, which were beneficial for improving of skin conditions. The fermentation process increased phytochemicals and antioxidant capacity. Thus, the purpose of this paper is to examine whether phytochemicals can be increased through the fermentation process of rambutan extracts to improve skin aging. Design/methodology/approach In this study, the authors used the three stages of fermentation with Saccharomyces cerevisiae, Lactobacillus plantarum TCI028 and Acetobacter aceti under red light to develop a fermented rambutan extract. Findings The level of polyphenols of red-light-based fermented rambutan extract (RLFRE) were significantly increased 108.9% (p < 0.01) and 97% (p < 0.01) compared with fermented rambutan extract (FRE) and pure rambutan extract (RE), respectively. The human skin fibroblasts treated with 0.03 or 0.06% of RLFRE can significantly decrease reactive oxygen species (ROS) levels by 0.74- (p < 0.001) and 0.84-fold (p < 0.001) compared with H2O2 group, respectively. And 0.03% of RLFRE can significantly increase in elastin content by 1.13-fold (p < 0.05). Also, ten compounds were identified including one new phenolic compound and nine known compounds from RLFRE. Moreover, red light could enhance the levels of compounds 4, 9 and 3 by 5, 2.5 and 2.5-fold, respectively, relative to the results of FRE. The last, RLFRE isolated compounds significantly facilitated the elastin content on fibroblast (compound 1, 7, 9, 10 compared with control: p < 0.001, compound 2 compared with control: p < 0.001). Originality/value In short, this was the first study to unveil that the red-light-based fermentation can enrich the antioxidant content in a rambutan extract and its product had the potential to be developed a functional product for health-promoting effects such as skin aging.