Effect of thermal treatments on the matrix components, inherent glycemic potential, and bioaccessibility of phenolics and micronutrients in pearl millet rotis.

Pearl millet (PM) is a nutri-cereal rich in various macro and micronutrients required for a balanced diet. Its grains have a unique phenolic and micronutrient composition; however, the lower bioaccessibility of nutrients and rancidity of flour during storage are the major constraints in its consumption and wide popularity. Here, to explore the effect of different thermal processing methods, i.e., hydrothermal (HT), microwave (MW), and infrared (IR) treatments, on the digestion of starch, phenolics, and microelements (Fe and Zn), an in vitro digestion model consisting of oral, gastric and intestinal digestion was applied to PM rotis. The hydrothermally treated PM roti was promising as it showed lower inherent glycemic potential (60.4%) than the untreated sample (72.4%) and less enzymatic activities associated with rancidity in PM flour. FTIR revealed an increased ratio of 1047/1022 cm-1 in the hydrothermally treated sample, reflecting the enhancement of the structurally ordered degree and compactness of starch compared to other thermal treatments. A tighter and more compact microstructure with an agglomeration of starch in the hydrothermally treated PM flour was observed by SEM. These structural changes could provide a better understanding of the lower starch digestion rate in the hydrothermally treated flour. However, HT treatment significantly (P < 0.05) reduced the bioaccessibility of phenolics (10.6%) compared to native PM rotis and slightly reduced the Fe (2%) and Zn (3.2%) bioaccessibility present in PM rotis.

Diversity in Phytochemical Composition, Antioxidant Capacities, and Nutrient Contents Among Mungbean and Lentil Microgreens When Grown at Plain-Altitude Region (Delhi) and High-Altitude Region (Leh-Ladakh), India.

Mungbeans and lentils are relatively easily grown and cheaper sources of microgreens, but their phytonutrient diversity is not yet deeply explored. In this study, 20 diverse genotypes each of mungbean and lentil were grown as microgreens under plain-altitude (Delhi) and high-altitude (Leh) conditions, which showed significant genotypic variations for ascorbic acid, tocopherol, carotenoids, flavonoid, total phenolics, DPPH (1, 1-diphenyl-2-picrylhydrazyl), FRAP (ferric-reducing antioxidant power), peroxide activity, proteins, enzymes (peroxidase and catalase), micronutrients, and macronutrients contents. The lentil and mungbean genotypes L830 and MH810, respectively, were found superior for most of the studied parameters over other studied genotypes. Interestingly, for most of the studied parameters, Leh-grown microgreens were found superior to the Delhi-grown microgreens, which could be due to unique environmental conditions of Leh, especially wide temperature amplitude, photosynthetically active radiation (PAR), and UV-B content. In mungbean microgreens, total phenolics content (TPC) was found positively correlated with FRAP and DPPH, while in lentil microgreens, total flavonoid content (TFC) was found positively correlated with DPPH. The most abundant elements recorded were in the order of K, P, and Ca in mungbean microgreens; and K, Ca, and P in the lentil microgreens. In addition, these Fabaceae microgreens may help in the nutritional security of the population residing in the high-altitude regions of Ladakh, especially during winter months when this region remains landlocked due to heavy snowfall.

Cytosine Methylation of Isoflavone Synthase Gene in the Genic Region Positively Regulates Its Expression and Isoflavone Biosynthesis in Soybean Seeds.

Plants, being sessile organisms, have evolved several dynamic mechanisms of gene regulation. Epigenetic modification especially cytosine methylation and demethylation actively regulates the expression of genes. To understand the role of cytosine methylation during isoflavonoid biosynthesis and accumulation, we performed cytosine methylation analysis in the coding region of two isoforms IFS1 and IFS2 gene, in two contrasting soybean genotypes differing in total isoflavone content (NRC37: high isoflavone; and NRC7: low isoflavone). The results indicated increased 5-mC in both the isoforms in NRC37 (∼20.51% in IFS2 and ∼85% in IFS1) compared with NRC7 (∼7.8% in IFS2 and ∼2.5% in IFS1) genotype, which signifies the positive role of 5-mC in the coding region of the gene leading to enhanced expression. In addition, temporal expression profiling [35 days after flowering (DAF), 45, 55, and 65 DAF] of both the isoforms showed increasing trend of accumulation in both the genotypes with maximum in NRC37 at 65 DAF. To further establish a correlation between methylation and expression of transcripts, we quantified the different isoforms of isoflavone in both the genotypes across all the stages. Therefore, the finding of this study would certainly increase our understanding of epigenetic regulation of isoflavone biosynthetic pathway mediated by the cytosine methylation that would assist molecular breeders to get high-performing soybean genotypes with better isoflavone yield.

Comparative Analysis of Tocopherol Biosynthesis Genes and Its Transcriptional Regulation in Soybean Seeds.

Tocopherols composed of four isoforms (α, ß, γ, and δ) and its biosynthesis comprises of three pathways: methylerythritol 4-phosphate (MEP), shikimate (SK) and tocopherol-core pathways regulated by 25 enzymes. To understand pathway regulatory mechanism at transcriptional level, gene expression profile of tocopherol-biosynthesis genes in two soybean genotypes was carried out, the results showed significantly differential expression of 5 genes: 1-deoxy-d-xylulose-5-P-reductoisomerase (DXR), geranyl geranyl reductase (GGDR) from MEP, arogenate dehydrogenase (TyrA), tyrosine aminotransferase (TAT) from SK and γ-tocopherol methyl transferase 3 (γ-TMT3) from tocopherol-core pathways. Expression data were further analyzed for total tocopherol (T-toc) and α-tocopherol (α-toc) content by coregulation network and gene clustering approaches, the results showed least and strong association of γ-TMT3/tocopherol cyclase (TC) and DXR/DXS, respectively, with gene clusters of tocopherol biosynthesis suggested the specific role of γ-TMT3/TC in determining tocopherol accumulation and intricacy of DXR/DXS genes in coordinating precursor pathways toward tocopherol biosynthesis in soybean seeds. Thus, the present study provides insight into the major role of these genes regulating the tocopherol synthesis in soybean seeds.