Partial and total defoliation during the filling period affected grain industrial and nutraceutical quality in soybean.

BACKGROUND: Little is known about soybean grain chemical composition response to defoliation. The objectives of our study were: (i) to quantify the impact of different levels and timing of defoliation during the filling period on soybean grain yield and grain chemical content and composition, including protein, oil, fatty acids, and isoflavones; and (ii) to establish associations between them and the level and timing of defoliation. RESULTS: Yield and grain chemical components were reduced by defoliation treatments, these effects being more pronounced as defoliation increased. Mild defoliation (33%) caused small or non-significant changes in yield, its components, protein, oil, and isoflavone contents and concentrations. However, it affected oil composition, increasing the degree of unsaturation, which became more accentuated as defoliation increased. Moderate defoliation (66%) produced similar relative reductions in protein and oil contents, with small effects in isoflavone content, resulting in a generally greater isoflavone concentration in defatted flour and a greater isoflavone/protein ratio in grain. Total defoliation (100%) produced greater relative reductions in oil and isoflavone contents than in protein content. These resulted in higher protein/oil ratio and protein concentration and lower isoflavone/protein ratio and isoflavone concentration. Analyzed variables were associated with cumulative solar radiation during grain filling; indeed, this parameter successfully captured the effects of defoliation intensity and timing. CONCLUSION: By exploring different levels and timings of defoliation during the filling period, our study provides novel and important information regarding the impact of light interception decreases on grain chemical components, with special emphasis on nutraceuticals. © 2022 Society of Chemical Industry.

Cassava starch as a stabilizer of soy-based beverages.

Soy-based beverages are presented as healthy food alternatives for human nutrition. Cassava (Manihot esculenta, Crantz) starch is relatively inexpensive, widely available in Brazil and is broadly used by the food industry due to its desired properties that result from pasting. The objective of this study was to develop soy-based beverages with good sensory quality using native cassava starch as a stabilizer and maintaining the nutritional value that makes this product a functional food. The developed formulations featured a range of cassava starch and soybean extract concentrations, which were tested in a 2² experimental design with three central points. The results of sensory analysis showed that the studied variables (cassava starch and soybean extract concentrations) did not have a significant effect with respect to a 5% probability level. When considering the apparent viscosity, on the other hand, the variables had a significant effect: the increase in soybean extract and cassava starch concentrations caused an increase in the viscosity of the final product. The profile of isoflavones in the tested formulations was similar to the profiles reported in other papers, with a predominance of the conjugated glycosides over the aglycone forms.

Evaluation of the shelf-life of vegetable-type soybean pods

The shelf-life of the vegetable-type soybean pods stored under different conditions was evaluated by chemical characteristics and color. The pods were harvested in the R6 stage and stored either at 30 or 7ºC for 9 d. After the storage period, the pods were blanched and threshed, and the immature green grains were used for the analysis. The protein content decreased after 6 d of storage at 7ºC. There was no difference in the lipid content after the storage at 30 and 7ºC for 9 d. The starch and sucrose contents decreased after the first day of storage at 30ºC. There was no difference in trypsin inhibitor activity until 6 d of storage at 30 and 7ºC. The green color of the pods that was an indication of the quality that was maintained when stored at 7ºC during 3 d. To preserve the quality of vegetable-type soybean, pods should be stored at 30ºC and consumed within 24 h or stored at 7ºC for up to 3 d of storage.