Sugar degradation process of mulberry (Morus alba L.) fruit was developed with microbial biotransformation

Abstract

Due to the high sugar content, fresh mulberry fruit was limited to the wide application in diet supplement designs for managing diabetes. Three kinds of microbial fermentation methods (lactobacillus, yeast aerobic, and yeast anaerobic fermentation) were compared to analysis the sugar reducing process of mulberry pulp in the present study. Based on the determination of nutrition and function bioactive components during the sugar reducing process, the evaluation models of principal component analysis were established to select the best method. The results showed that among the three kinds of fermentation methods, the optimum fermentation condition was selected for 96 hr by lactobacillus, with a degradation rate of 86.49% for fructose and 66.12% for glucose. During this process, lactic acid, and acetic acid were produced accordingly. The viable content of Leuconostoc mesenteroides was 818 lg CFU/ml at this point. The contents of C3G, C3R Pg3G and DNJ in mulberry pulp were 889.42, 857.16, 20.61, 27.92 mg/ml, respectively. In addition, the ORAC value was 45.07 µmol TE/ml and α‐glucosidase inhibitory activity reached 44.2% after 96 hr of fermentation. In general, compared with yeast fermentation, lactobacillus fermentation had lower utilization rate of sugar but less degradation effect on functional ingredients in mulberry pulp. Yeast fermentation had higher sugar utilization rate and greater effect on functional ingredients. Practical applications Three microbial fermentation methods were compared to select the optimal process. The purpose was to consume sugar components and retain the original hypoglycemic functional factors in mulberry pulp as far as possible. The results will provide possible application in diet designs for managing diabetes.

The hypoglycemic effect of freeze‐dried fermented mulberry mixed with soybean on type 2 diabetes mellitus

“…After fermentation, the soybean was beaten into sirup and added to the fermented mulberry liquid and stirred evenly, and then freeze‐dried. The mass ratio of soybean sirup to the fermentation liquid was 1:5, according to our laboratory's previous research (Li et al., 2017).…”

“…However, it contains relatively high levels of fructose and glucose, which are not suitable for excess consumption by diabetic patients. It was proved that the microorganisms could reduce the carbohydrate content of mulberry (Hanstock et al., 2004; Li et al., 2017; Wang et al., 2010). Li et al studied the sugar‐reducing rate of different microorganisms of mulberry, and the result verified that the degradation rate of fructose and glucose was 86.49% and 66.12% respectively after fermentation by lactobacillus (Li et al., 2017).…”

“…It was proved that the microorganisms could reduce the carbohydrate content of mulberry (Hanstock et al., 2004; Li et al., 2017; Wang et al., 2010). Li et al studied the sugar‐reducing rate of different microorganisms of mulberry, and the result verified that the degradation rate of fructose and glucose was 86.49% and 66.12% respectively after fermentation by lactobacillus (Li et al., 2017). In our previous study (Long et al., 2020), we have confirmed that the fermented mulberry plays the better hypoglycemic effect than the unfermented mulberry in T2DM mice, which may be related to the change of bioactive substance content.…”