Development of Nutritionally enriched Soymilk using a Mixed Probiotic Fermentation by Lacticaseibacillus rhamnosus JCM 1136 and Weissella confusa 30082b

Author: Minnu Sasi, Sandeep Kumar and Anil Dahuja

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Abstract

The soybean products, on account of the presence of health-giving compounds like isoflavones, phospholipids, and polyunsaturated fatty acids, have immense potential to enhance human health. Single strain probiotic soy foods may exhibit many challenges associated to their growth, survival, viability, stability and functionality in food processing, storage and consumption as well as changes of sensory characteristics of probiotic foods. Mixed culture fermentations are generally implemented to stimulate the production of nutritional compounds and enzymes resulting from positive mutual interactions between the bacteria, called protocooperation. With this aim, potential techno-functional properties of soymilk fermented with mixed cultures of Lacticaseibacillus rhamnosus JCM 1136 and Weissella confusa 30082b have been studied. The investigations on the effect of probiotic fermentation after 6, 24, 30, 48 h and 7th day of storage indicate a decrease in pH (5.76 to 4.76), an increase in titratable acidity (0.19% to 0.47%), an increase in TAO (33.13-67.86%), reduction in phytic acid (1.185-0.339g per 100g), increase in free mineral content- Fe (0.31-2.08μg/ml) & Zn (0.26-1.15μg/ml), bioconversion of isoflavone glycosides into more bioavailable aglycones (daidzein-18.708-99.24; glycitein- 18.586- 43.41; genistein-20.778-67.64µg/10ml), detected for unfermented control and 1%(v/v) mixed culture fermented soymilk, respectively. The viable count of bacteria was maintained up to 3.32 × 108 CFU/ml for mixed cultures after 7 days of storage at 4oC. However, the values of nutritive factors were observed to be augmented and anti-nutritional factors seemed to be reduced after mixed culture fermentation. Hence, mixed culture fermentation with Lacticaseibacillus rhamnosus JCM 1136 and Weissella confusa 30082 bis an ideal strategy to guide consumers towards appropriate prophylactic and therapeutic uses of probiotics that deliver the desired beneficial health effects.

Keywords

Lactic acid bacteria; mixed fermentation; nutraceutical potential; mineral bioavailability; phytic- acid; isoflavones

Conclusion

Mixed culture fermentations are generally implemented to stimulate the production of nutritional compounds and enzymes resulting from positive mutual interactions between the bacteria, called protocooperation. Our studies indicate that the interaction between these strains with homofermentative (L. rhamnosus) and heterofermentative (W. confusa 30082b) metabolisms increased the yield of metabolites which could stimulate the growth of these microorganisms, thus increasing the cell viability. As a result of fermentation, there was the production of lactic acid, acetic acid, ethanol, and CO2, which combinedly reduced the pH of the soymilk from 6.0 to 4.5 while enhancing the titratable acidity from 0.10 to 0.33%. As a consequence, the action of β- glucosidases and phytases were found to increase, leading to the enhanced bioconversion of isoflavone glucosides to aglycones as well as phytic acid to free phosphate. The generation of genistein and daidzein aglycones which are potent antioxidants boosted the antioxidant activity of soymilk. The degradation of phytate, a metal chelating ANF, enhanced the bioavailable content of Fe and Zn in the fermented soymilk. Overall, mixed culture fermentations with probiotic bacteria were manifested to enhance the microbial stability and fitness, shelf life, and safety of the fermented food products. The co-inoculation of Weissella confusa and L. rhamnosus could reproduce the metabolic and microbial processes of fermentation, enhancing the nutritional and sensory quality of the fermented products. Also, for the more efficacious utilization of soybean, which harbours a plethora of ANFs, it is desirable to carry out mixed culture fermentation to lower their concentrations. Also, it could improve the sensory properties, and microstructure and increase the bioavailability of nutrients and yield of targeted bioactive compounds either through microbial synthesis or by augmenting the digestibility of the fermented product. The drawback of commercial soy- probiotics is the inability to deliver sufficient probiotics to the acidic lower gastrointestinal tract, which entails developing a more peculiar target delivery system and proper formulations. The industrial production of probiotics is still challenging because of their prerequisite for a rich culture media anaerobic environment, maintaining an optimal fermentation process and assembling the final product while perpetuating its quality. In the future, to cope with the pitfalls of probiotic soy foods and enhance their functionality, a better understanding of the probiosis mechanisms and more advanced cultivation technologies need to be formulated.

References

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How to cite this article

Minnu Sasi, Sandeep Kumar and Anil Dahuja (2023). Development of Nutritionally enriched Soymilk using a Mixed Probiotic Fermentation by Lacticaseibacillus rhamnosus JCM 1136 and Weissella confusa 30082b. Biological Forum – An International Journal, 15(4): 330-340.