Main content area

Impact of soaking process on the microstructure of cowpea seeds in relation to solid losses and water absorption

Coffigniez, Fanny, Briffaz, Aurélien, Mestres, Christian, Akissoé, Lorène, Bohuon, Philippe, El Maâtaoui, Mohamed
Food research international 2019 v.119 pp. 268-275
microstructure, proteins, testa, cowpeas, pectins, models, starch, cotyledons, cellulose, soaking, antinutritional factors, temperature, nutrients, water uptake
A cytohistological investigation was performed to better understand the structural alterations of cowpea seeds in relation with soaking. Thin sections obtained from seeds soaked at 30 °C, 60 °C and 95 °C were treated to specifically visualize starch, proteins, cellulose and pectin. Micropyle behavior as well as water uptake and dry matter loss were also monitored. A Soaking at 30 °C induced slight alteration of parenchymatous cells of cotyledons, whereas drastic alterations were observed at 60 °C and intense alterations at 95 °C. All these structural modifications of cells could explain losses of nutrients and antinutritional factors at the highest soaking temperature (95 °C). The size of the apertures in the micropyle sections varied depending on both soaking temperature and time. At 30 °C and 60 °C, the micropyle aperture enabled notable water uptake by seeds. At 95 °C, water was entirely taken up through the testa. These results show that models describing nutrients losses and water uptake should account for these structure changes during soaking of legumes.