Effect of processing on carbohydrate profile of different biofortified varieties of soybean

Soybeans (Glycine max (L.) Merrill) are a widely cultivated legume with significant nutritional benefits, contributing to increasing global production and consumption. Processing methods influence the sensory appeal, nutritional value, and bioavailability of soybeans, impacting their dietary benefits. This study evaluates the effect of different processing techniques—soaking, germination, malting, blanching, boiling, pressure cooking, and roasting—on the total, reducing, and non-reducing sugar content of two biofortified soybean varieties, NRC 127 and NRC 142. The results indicate that fermentation led to the highest increase in total and reducing sugar content due to enzymatic hydrolysis, with reducing sugars rising by approximately 140% and 144% in NRC 127 and NRC 142, respectively. Germination and malting also significantly increased sugar content, attributed to the activation of enzymes such as β-galactosidase, which breaks down complex carbohydrates into simpler sugars. Conversely, boiling and pressure cooking resulted in a significant reduction in total sugar due to solubilization and leaching of sugars into water, aligning with previous findings. Roasting for 10 minutes led to a decline in both reducing and non-reducing sugars, with NRC 142 showing a greater reduction compared to NRC 127. The study also found that roasting and germination had notable effects on starch content, with the highest starch loss observed in roasted NRC 127 and germinated NRC 142. Overall, fermentation proved to be the most effective method for increasing sugar content, whereas boiling, pressure cooking, and roasting led to substantial reductions. These findings provide valuable insights into the impact of processing on soybean composition, which can be leveraged for optimizing nutritional quality in soybean-based food products.