Improvement of the functional value of green soybean (edamame) using germination and tempe fermentation: A comparative metabolomics study

Multi-Omics Analysis Provides Insights into Green Soybean in Response to Cold Stress

Green soybean (Glycine max (L.) Merrill) is a highly nutritious food that is a good source of protein and fiber. However, it is sensitive to low temperatures during the growing season, and enhancing cold tolerance has become a research hotspot for breeding improvement. Background/Objectives: The underlying molecular mechanisms of cold tolerance in green soybean are not well understood. Methods: Here, a comprehensive analysis of transcriptome and metabolome was performed on a cold-tolerant cultivar treated at 10 °C for 24 h. Results: Compared to control groups, we identified 17,011 differentially expressed genes (DEGs) and 129 differentially expressed metabolites (DEMs). The DEGs and DEMs were further subjected to KEGG functional analysis. Finally, 11 metabolites (such as sucrose, lactose, melibiose, and dehydroascorbate) and 17 genes (such as GOLS, GLA, UGDH, and ALDH) were selected as candidates associated with cold tolerance. Notably, the identified metabolites and genes were enriched in two common pathways: 'galactose metabolism' and 'ascorbate and aldarate metabolism'. Conclusions: The findings suggest that green soybean modulates the galactose metabolism and ascorbate and aldarate metabolism pathways to cope with cold stress. This study contributes to a deeper understanding of the complex molecular mechanisms enabling green soybeans to better avoid low-temperature damage.

Gas chromatography-mass spectrometry analysis of metabolites in finger millet and Bambara groundnut as affected by traditional and novel food processing

Metabolite profiling is an analytical technique used to assess metabolites in complex biological samples. This technique allows for the identification of both targeted and untargeted metabolites. In this study, the effect of traditional (fermentation and malting) and novel processing (ultrasonication) on the metabolites of finger millet (FM) and Bambara groundnut (BGN) flour was investigated using gas chromatography-mass spectrometry. Various metabolite classes, including amino acids, alcohol, aldehyde, organic acid, ester, fatty acids, glycoside, and sugar, were identified in FM and BGN flours. The adopted processing techniques impacted metabolite composition, as evidenced by substantial variations in volatile compound levels and metabolite composition among the FM and BGN samples before and after traditional and novel processing. Important health-promoting compounds, such as oleic acid, linoelaidic acid, and linoleic acid, were identified at their highest levels in fermented FM and BGN flours. The results obtained from this study offer an important context for monitoring and regulating the metabolite composition of FM and BGN flours under traditional and novel processing. PRACTICAL APPLICATION: Fermentation, malting, and ultrasonication induced desirable changes in some health-promoting compounds of finger millet and Bambara groundnut flours. The food and pharmaceutical industries could benefit from these traditional- and novel-modified flours as they could be used as improved food sources with health benefits.

Effects of Climate Conditions before Harvest Date on Edamame Metabolome

Edamame is a green soybean that is rich in nutrients. Boiled edamame has been traditionally used for food in the East Asia region. It was known among farmers that conditions, such as temperature and climate on the day of harvest, affect the quality of edamame. Large-scale farmers harvest edamame on multiple days in the same year; however, the quality of edamame varies from day to day due to variations in climate conditions. In this study, we harvested edamame over several days between 2013 and 2018, obtained the climate conditions on the harvest date, and performed metabolome analysis using capillary electrophoresis mass spectrometry. To clarify the correlation between climate conditions before the harvest date and edamame components, comparative analyses of the obtained meteorological and metabolomic data were conducted. We found positive and negative correlations between the sunshine duration and average temperature, and the amounts of some edamame components. Furthermore, correlations were observed between the annual fluctuations in climate conditions and edamame components. Our findings suggest that the climate conditions before the date of harvesting are closely related to edamame quality.