Exploring alcoholic and acetic fermentations of Ceri Terengganu (Lepisanthesfruticosa): physicochemical and bioactive compound changes

Ceri Terengganu (Lepisanthes fruticosa), an underutilized exotic fruit native to Malaysia, has been overlooked due to limited cultivation and low economic value. This study aimed to highlight the potential of Ceri Terengganu by exploring its alcoholic fermentation using Saccharomyces cerevisiae and its acetic fermentation using Acetobacter aceti. The feasibility of using Ceri Terengganu as a substrate in both fermentations was examined, along with the physicochemical, antioxidant activity, and bioactive compound changes during the fermentation process. During alcoholic fermentation, yeast counts increased in the early stage and stabilized by day 3–5, while pH and total soluble solids progressively declined. The highest ethanol yield (6.41%) was recorded on day 8 with 15% sucrose supplementation. Subsequent acetic fermentation with A. aceti led to an increase in acetic acid concentration from 0.62% to 3.43%, accompanied by a decrease in ethanol, pH, and total soluble solids. Notably, acetic fermentation enhanced the total phenolic content of Ceri Terengganu. While the fruit itself is known for its high antioxidant activity, no significant changes in antioxidant activity were observed. However, acetic fermentation improved the flavonoids and phenolic acids content, with epigallocatechin (65.57±4.1 µg/ mL) and protocatechuic acid (12.75±3.2 µg/mL) being the most abundant, respectively. The acetic fermentation product exhibited high levels of acetic acid (56790.56±56.8 µg/ mL) and citric acid (7662.25±64.56 µg/mL). In conclusion, Ceri Terengganu shows promise as a substrate for alcoholic and acetic fermentations, resulting in fermented products enriched with beneficial bioactive compounds. This research sheds light on the potential value and health benefits of this underutilized Malaysian tropical fruit, contributing to its wider recognition and application in the food industry.