Impact of Germination on the Microstructural and Physicochemical Properties of Different Legume Types

Abstract

The microstructural and physicochemical compositions of bean (Phaseolus vulgaris), lentil (Lens culinaris Merr.), soybean (Glycine max L.), chickpea (Cicer aretinium L.) and lupine (Lupinus albus) were investigated over 2 and 4 days of germination. Different changes were noticed during microscopic observations (Stereo Microscope, SEM) of the legume seeds subjected to germination, mostly related to the breakages of the seed structure. The germination caused the increase in protein content for bean, lentil, and chickpea and of ash content for lentil, soybean and chickpea. Germination increased the availability of sodium, magnesium, iron, zinc and also the acidity for all legume types. The content of fat decreased for lentil, chickpea, and lupine, whereas the content of carbohydrates and pH decreased for all legume types during the four-day germination period. Fourier transform infrared spectroscopic (FT-IR) spectra show that the compositions of germinated seeds were different from the control and varied depending on the type of legume. The multivariate analysis of the data shows close associations between chickpea, lentil, and bean and between lupine and soybean samples during the germination process. Significant negative correlations were obtained between carbohydrate contents and protein, fat and ash at the 0.01 level.

Development of Antioxidant and Nutritious Lentil (Lens culinaris) Flour Using Controlled Optimized Germination as a Bioprocess

“…The impact of temperature did not show a clear trend, since both low and high temperatures caused the highest carbohydrate increment, while medium temperatures were related with the lowest carbohydrate levels. In contrast, longer times reduced the content of carbohydrates in sprouted lentil flour, especially at higher temperatures ( Figure 1 c), findings in agreement with those reported in lentil germinated for 1–4 days [ 41 , 42 ]. The activation of a wide range of hydrolytic enzymes, including α-amylase, glucosidase, and dextranase existing in the aleurone layers, and β-amylase present in the endosperm that hydrolyze starch to produce energy [ 43 ] may be involved in the reduction of carbohydrate content during the germination.…”

“…Germination temperature and time showed a linear impact on fat levels of sprouted lentil flour, but the mathematical model obtained showed a poor agreement between experimental and predicted data, considering the low R 2 value (0.34, data not shown). As depicted in Figure 1 b, germination caused a decrease in fat content during germination, with the lowest fat values at higher temperatures and longer times, in agreement with other authors, who observed reductions of lipid content from 17 to 68% in lentil germinated for 4–6 days at 25 °C [ 38 , 41 ]. The activation during sprouting of endogenous lipolytic enzymes that hydrolyze triacylglycerol to release free fatty acids, which are oxidized to produce energy for seedling development [ 38 ], is mainly responsible for the reduction in fat content in germinated lentil flour.…”

“…Lentil seed showed a content of carbohydrates of 62.96 ± 0.39 g 100 g −1 response variables, levels close to that observed by Atudorei et al [ 41 ], who found a value of 60 g 100 g −1 in non-sprouted lentil. Germination temperature and time performed quadratic and linear and interaction effects on the levels of carbohydrates ( Table 2 ).…”

“…The starch levels decreased as germination time increased ( Figure 10 a). As expected, starch is the major energy reserve used by the seed during germination, which is produced by mobilization of starch during the early stage of germination, resulting in the release of free sugars [ 41 ]. As germination time increased up to 72 h, the content of starch decreased probably due to the maximum activity of α-amylase, which slows down changes in starch content at longer germination times.…”

Dough Rheological Properties, Microstructure and Bread Quality of Wheat-Germinated Bean Composite Flour

“…Different studies reported that beans contain a higher amount of protein than white wheat flour [ 23 , 90 ]. Taking into account that germination leads to an increase in the amount of protein in beans [ 91 ], then it may be concluded that the samples of bread with the GBF addition will contain a higher amount of proteins. The darkening of the bread samples with the increase amount of GBF addition could also be explained by the fact that the amount of phenolic compound increases [ 92 ].…”