Fermentation and germination improve nutritional value of cereals and legumes through activation of endogenous enzymes

Abstract

Cereals and legumes are outstanding sources of macronutrients, micronutrients, phytochemicals, as well as antinutritional factors. These components present a complex system enabling interactions with different components within food matrices. The interactions result in insoluble complexes with reduced bioaccessibility of nutrients through binding and entrapment thereby limiting their release from food matrices. The interactions of nutrients with antinutritional factors are the main factor hindering nutrients release. Trypsin inhibitors and phytates inherent in cereals and legumes reduce protein digestibility and mineral release, respectively. Interaction of phytates and phenolic compounds with minerals is significant in cereals and legumes. Fermentation and germination are commonly used to disrupt these interactions and make nutrients and phytochemicals free and accessible to digestive enzymes. This paper presents a review on traditional fermentation and germination processes as a means to address myriad interactions through activation of endogenous enzymes such as α‐amylase, pullulanase, phytase, and other glucosidases. These enzymes degrade antinutritional factors and break down complex macronutrients to their simple and more digestible forms.

Quality Evaluation of Cookies from Malted Sorghum (Sorghum bicolor), Sprouted Soybean (Glycine max) and Carrot (Daucus carota) Flour Blends

“…Minerals such as magnesium, potassium and zinc are formed during the germination process. The higher the ash content, the higher the mineral content of the food [61]. Result obtained for ash contents of cookies in this study having the ash values ranging between 1.34-3.78% is higher than the result of ash content (1.00-1.82%) of cookies baked from blends of soybean and maize flour by [45].…”

Functional properties of powders produced from either or not fermented mealworm (Tenebrio molitor) paste

“…An increase in crude protein content may be attributed to loss of dry matter (mainly carbohydrates). A decrease, on the other hand, can be caused by degradation of proteins by microorganisms, thereby releasing peptides and amino acids (Nkhata et al, 2018). As these components are necessary for microbial growth and organic acids production by Lactic Acid Bacteria (Klupsaite et al, 2017), it is possible that the starters use the generated peptides and amino acids, thereby lowering the protein content of the fermented powders.…”

Extrusion and nixtamalization conditions influence the magnitude of change in the nutrients and bioactive components of cereals and legumes

“…Phytochemicals are potent antioxidants which scavenge free radicals that may cause oxidative stress. They are found embedded in food matrices thereby reducing their bioavailability (Nkhata et al, ). Extrusion helps disrupt the food matrix and make phytochemicals more bioaccessible (Ti et al, ) through increased gelatinization of starch, denaturation of protein that bind these phytochemicals, and breaking down of many complexes in which these compounds are embedded or entrapped (Wolfe & Liu, ).…”

“…This therefore suggests that the health promoting antioxidant properties of phytochemicals is secondary to providing nutrients in developing countries. Moreover, phytochemicals may lower the nutritional quality of the diet through mechanisms that include inhibition of digestive enzymes, binding, and complexation with minerals making them unavailable for absorption (Nkhata et al, ). For example, ferulic acid, a major phenolic acid in maize, inhibits α‐amylase enzymes responsible for starch digestion.…”

“…Consequently, adoption of food processing and preservation methods seems handy in enhancing nutrient availability and also extending shelf life of product. While traditional food processing methods such as fermentation and germination have been reported to increase bioaccessibility and ultimate bioavailability of nutrients (El‐Hag, El‐Tinay, & Yousif, ; Hubert, Berger, Nepveu, Paul, & Dayde, ; Nkhata, Ayua, Kamau, & Shingiro, ), there are other processing techniques serving similar roles such as extrusion and nixtamalization.…”