Dynamics of Germination Behaviour, Protein Secondary Structure, Technofunctional Properties, Antinutrients, Antioxidant Capacity and Mineral Elements in Germinated Dhaincha
Department of Food Science and Technology, Punjab Agricultural University, Ludhiana-141004 (Punjab), India
Received: 28 July 2020
Accepted: 19 May 2021
processed dhaincha, bioactive components, functional properties, FTIR
Research background. Dhaincha (Sesbania aculeate) is a forage legume which is primarily used for green manuring and animal feeding. Good nutritional profile of dhaincha makes it a potential alternative legume in human nutrition. However, the presence of high amount of antinutrients poses problem in its utilisation for food applications. The present investigation intends to germinate dhaincha seeds at different time-temperature regimes and to evaluate the process of germination to ascertain optimal germination conditions and improve its potential for utilisation.
Experimental approach. Dhaincha seeds were germinated at 24, 28 and 32 °C for 24, 48 and 72 h. Germination characteristics and germination loss, spectral characteristics, techno-functionality, antinutrients, bioactive constituents, antioxidant capacity and mineral elements were evaluated. Optimal balance of technobiofunctionality of germinated dhaincha seeds was validated by principal component analysis.
Results and conclusions. Sprout length and germination loss increased with the higher germination temperature and prolonged germination time. Seeds showed similar germination rate at 28 and 32 °C and it was markedly higher than at 24 °C Germination for 24 h resulted in mild conformational changes in the secondary structure of proteins, whereas germination for 48 and 72 h exhibited major conformational changes in the β-sheets, resulting in improvement in the hydration and foaming properties. Progression of germination (72 h) caused the decrease of tannins (24.47 %), phytic acid (16.38 %), saponin (24.58 %) mass fractions, and trypsin inhibitor (40.33 %) and lectin activity (62.50 %). Slight decrease of DPPH∙ (3.7 %) and ABTS∙+ (18.5%) values was also observed, whereas total flavonoid content (36.14 %) and metal chelating activity (26.76 %) increased. Total phenolics, FRAP, and reducing power decreased after 24 h, followed by a gradual increase. Zinc extractability increased drastically with germination. Germination at 28 °C for 72 h resulted in higher reduction of antinutrients with optimal retention of antioxidant activity and better functional characteristics, as validated by principal component analysis.
Novelty and scientific contribution. Dhaincha is an unknown crop in Europe, and even in Asia it is predominantly used as green manure and animal feed. This research demonstrated that that intervention in germination can transform dhaincha into a promising crop for food industry. Germinated dhaincha exhibited enhanced technobiofunctionality for utilisation in various food formulations.