PHYTOCHEMICAL INVESTIGATION OF SOME UNDERUTILIZED CEREALS IN INDIA

Abstract

The thesis titled “Phytochemical investigation of some underutilized cereals in India” focuses on the comprehensive exploration of the bioactive compounds, nutritional analysis, and biological profiling of the selected underutilized cereals of India. The present thesis aimed to investigate the phytochemical and biological profiling of selected underutilized cereal samples of India - adzuki beans (Vigna angularis), mung beans (Vigna radiata), horse gram/kulthi beans (Macrotyloma uniflorum), little millet (Panicum sumatrense), and rice beans (Vigna umbellata), followed by proper identification, authentication, and sequential Soxhlet extraction using different polarity solvents and to further evaluate their potential for functional food applications. All five selected cereal samples were subjected to a detailed proximate analysis, fatty acid methyl ester analysis, elemental analysis, amino acid profiling, and phytochemical analyses using GC-MS and UHPLC-QTOF-MS to establish a comprehensive profile of their nutritional and metabolite content. The phytochemical screening focused on both qualitative and quantitative estimation of major as well as minor phytoconstituents such as phenolics, flavonoids, tannins, saponins, alkaloids, and phytosterols, using GC-MS and UHPLC-QTOF-MS. Based on the distinct phytochemical profile and literature evidence, adzuki bean and mung bean were selected for the evaluation of anti-obesity activities through in-vitro pancreatic lipase and HMG-CoA reductase inhibition assays. The nutritional assessment highlights that these underutilized cereals are a valuable source of essential macronutrients - namely carbohydrates, protein, and dietary fiber - in addition to a wide array of amino acids (essential, non-essential, and non-proteinogenic amino acids). The phytochemical profiling of these underutilized cereals revealed that the different solvent extracts contained flavonoids, terpenoids, and phenols. Various secondary metabolites were identified using a non-targeted approach, which belong to several natural product classes, including flavonoids, sugars, amino acids, fatty acids, fatty acid derivatives, and other organic acids. Through a targeted approach, vi metabolites including catechin-7-O-glucoside, catechin, epicatechin, quercetin, gallo-catechin, gallic acid, caffeic acid, para-coumaric acid, and glycitein were identified using UHPLC-QTOF-MS. In-vitro anti-obesity activity revealed the effectiveness of adzuki and mung beans as potent HMG-CoA reductase and pancreatic lipase inhibitors. The findings of anti-obesity activities indicate that adzuki beans and mung beans can be utilized to prevent obesity and related disorders. This research not only emphasizes the nutritional and biological value of these lesser-known cereals but also explores the formulation and evaluation of novel breakfast cereals/flakes and nutritional cookies developed from underutilized legumes - Vigna radiata (mung bean) and Vigna angularis (adzuki bean)- as sustainable, plant- based interventions to combat obesity and related disorders. Incorporating these legumes enhances the formulations' protein, fiber, and micronutrient content and introduces bioactive compounds with significant health benefits like weight loss and cholesterol lowering benefits. An important milestone of this work was the commercial interest, leading to collaboration with Kalsubai Purest Company, a local food enterprise based in Maharashtra. Based on my research formulations, their R&D team created a trial batch and is currently working toward market launch as a nutritious and functional food. The significance of this research was further recognized through an appreciation letter from Kalsubai Purest Company, acknowledging its practical value and real-world applicability. In addition to product development application of these underutilized cereals, we also investigated the potential of underutilized cereals’ mucilage and further explored their application by synthesizing mucilage-based hydrogels. For this purpose, we have explored four new sources of mucilage, namely adzuki beans, amaranth, proso millet, and little millet. The underutilized cereals’ mucilage application has been examined by developing hydrogels through the free radical copolymerization technique. This study demonstrated that the mucilage isolated from underutilized cereals might be a good feedstock for a hydrogel-forming agent, which can be explored in the food, cosmetics, and pharmaceutical industries. vii Overall, this work provides a comprehensive evaluation of the selected underutilized Indian cereals, identifying key bioactive metabolites and demonstrating their potential in the development of anti-obesity and cholesterol-lowering novel functional foods. The study not only contributes to scientific understanding of these neglected cereals but also supports their integration into sustainable food systems, promoting both nutrition security and agricultural biodiversity.