Enterococcus faecalis-Induced Biochemical Transformation during Fermentation of Underutilized Solenostemon monostachyus Leaves

Abstract

Solenostemon monostachyus is an underutilized plant that is yet to be explored for consumption. This study assessed the biochemical impacts of a probiotic Enterococcus faecalis as an agent of fermentation, promoting the edible properties of the leaves from S. monostachyus using either an unfermented water leaf or S. monostachyus. The results with p < 0.05 were considered statistically significant. The α-amylase activity, proteins, carbohydrates, and ash, iron, and copper contents significantly increased (p < 0.05), while fats, crude fiber, cadmium, and manganese contents of the fermented S. monostachyus leaves were significantly reduced (p < 0.05), compared to the control (unfermented water leaves). The total phenol and saponin contents of the leaves were 1.98 ± 0.03 and 2.77 ± 0.04 mg GAE/mL for the S. monostachyus, 2.20 ± 0.01 and 2.39 ± 0.51 mgGAE/mL for water leaf, respectively on Day 5. Spirostanol (20.7343 mg/10 g) and two possible yet-to-be-identified saponin compounds P-S1 (33.5773 mg/10 g) and P-S2 (23.5718 mg/10 g) were newly synthesized along with one possible novel volatile compound by the fermentation process. Furostanol (19.873–29.420), gallic acid (88.111–98.949 mg/10 g), luteolin (0.954–11.712 mg/10 g) were retained, and aescin (69.510 mg/10 g) was completely consumed by the fermentation process. E. faecalis derived some micronutrients to drive the α-amylase catalyzed biotransformation of phytochemicals to improve the health benefits in the leafy vegetable.