A Novel Combined Mung Bean and Mulberry Powder: Combination Index and Shelf Life of Total Phenolic, Anthocyanin, and GABA Contents and Neuroprotective Activity

Plant-based products are widely used in the food industry. This study aims to develop neurofunctional ingredients derived from mung beans with mulberry fruit powder, evaluate their phytochemical contents (total phenolic, anthocyanin, and GABA contents), impact of anti-oxidant activities (DPPH free radical scavenging inhibition and Ferric Reducing Ability Power (FRAP)) and neuroprotective activities (acetylcholinesterase (AChE), monoamine oxidase (MAO), MAO type A, and gamma-aminobutyric acid transaminase (GABA-T)), and focus on their shelf life. Result: A total of nine ratios of mung beans and mulberry fruit powder mix were evaluated, which showed that a ratio of 1:3 (g/g) provided better IC50 values of antioxidant and neuroprotective activities than other ratios, and showed a combination index (CI < 1) which was interpreted as a synergistic effect on AChE inhibition. Thus, this ratio was selected to make freeze-dried powder (mung bean mix mulberry fruit powder (MMP)), and its shelf life was evaluated as showing stability in its phytochemical contents (except GABA, which was reduced by more than 50% at 30 ± 2 °C) and antioxidant and neuroprotective activities, which remained stabilized at more than 50% in both real-time and accelerated conditions for 6 months and 8 weeks, respectively. During 1 to 6 months of storage at 4 °C, IC50 values of FRAP showed inhibited DPPH, AChE, MAO, MAO-A, and GABA-T levels in ranges of 4.43-6.69 mg/mL, 4.10-4.68 mg/mL, 5.18-5.90 mg/mL, 4.95-5.43 mg/mL, 5.93-6.42 mg/mL, and 5.05-5.53 mg/mL respectively, not significantly different when compared to 0 months. Conclusion: These findings indicate that the shelf life of the bioactivities of MMP remain stabilized for up to six months, so it could be applied in the food industry for use as a healthy plant-based supplement.