Development of Blood Sugar Regulatory Products from Momordica cochininensis via Probiotic Fermentation

Type II diabetes is the most important health issue in the whole world. Besides the use of prescribed drugs to control blood glucose level, recently, the development of health supplements is being actively explored. Owing to its high nutritional value, Momordica cochinchinensis Spreng. (Gac) is potentially a good source for developing this supplement. In recent years, the aril of Gac has been utilized as a substrate for developing various forms of supplements, but the pulp has been neglected as a byproduct. However, the pulp contains lots of phytochemicals that could provide health benefits, and the investigation using lactobacilli to ferment the pulp juices to lower blood glucose is not yet to be explored. Therefore, we set out to investigate the potential to develop the pulp-based juices for controlling blood glucose level by selecting an optimal strain of lactobacillus to ferment the pulp juice and measuring the inhibitory action of the fermented juice on α-glucosidase. This enzyme is crucial for controlling postprandial glucose absorbed into the bloodstream because it is the enzyme that hydrolyzes the carbohydrates to release glucose. First, we have successfully isolated a strain of lactobacillus which was capable of fermenting the pulp to produce α-glucosidase-inhibitory activity. Through a 16S rRNA sequence, this lactobacillus was named Lactiplantibacillus plantarum GBI 001. The optimal conditions for its growth in commercial culture medium were found to be 35 °C for 16 h to produce the highest α-glucosidase activity (72.03%). The optimal conditions for the strain to grow in Gac pulp juice were: 20% pulp juices as substrate with an initial pH adjusted to 4.0, growing at 35 °C for 16 h. Under these conditions, the fermented juice exhibited α-glucosidase activity of 24.36%, which is a 2.17-fold increase over the control group (11.23%). From its increase in α-glucosidase potency, using L. plantarum GBI 001 to ferment the pulp juices of Gac as soft drinks has great potential to develop a helpful drink as a food supplement to control postprandial blood glucose in patients with diabetes.