Sensory evaluation andin vitro protein digestibility of mung bean as affected by cooking time

Recent advances in mung bean protein: From structure, function to application

With the surge in protein demand, the application of plant proteins has ushered in a new wave of research. Mung bean is a potential source of protein due to its high protein content (20-30 %). The nutrition, structure, function, and application of mung bean protein have always been a focus of attention. In this paper, these highlighted points have been reviewed to explore the potential application value of mung bean protein. Mung bean protein contains a higher content of essential amino acids than soybean protein, which can meet the amino acid values recommended by FAO/WHO for adults. Mung bean protein also can promote human health due to its bioactivity, such as the antioxidant, and anti-cancer activity. Meanwhile, mung bean protein also has well solubility, foaming, emulsification and gelation properties. Therefore, mung bean protein can be used as an antioxidant edible film additive, emulsion-based food, active substance carrier, and meat analogue in the food industry. It is understood there are still relatively few commercial applications of mung bean protein. This paper highlights the potential application of mung bean proteins, and aims to provide a reference for future commercial applications of mung bean proteins.

Mung bean protein as an emerging source of plant protein: a review on production methods, functional properties, modifications and its potential applications

Plant protein is rapidly becoming more of a prime interest to consumers for its nutritional and functional properties, as well as the potential to replace animal protein. In the frame of alternative protein new sources, mung bean is becoming another legume crop that could provide high quality plant protein after soybean and pea. In particular, the 8S globulins in mung bean protein have high structural similarity and homology with soybean β-conglycinin (7S globulin), with 68% sequence identity. Currently, mung bean protein has gained popularity in food industry because of its high nutritional value and peculiar functional properties. In that regard, various modification technologies have been applied to further broaden its application. Here, we provide a review of the composition, nutritional value, production methods, functional properties and modification technologies of mung bean protein. Furthermore, its potential applications in the new plant-based products, meat products, noodles, edible packaging films and bioactive compound carriers are highlighted to facilitate its utilization as an alternative plant protein, thus meeting consumer demands for high quality plant protein resources. © 2023 Society of Chemical Industry.

Combined Effects of Calcium Addition and Thermal Processing on the Texture and In Vitro Digestibility of Starch and Protein of Black Beans (Phaseolus vulgaris)

Legumes are typically soaked overnight to reduce antinutrients and then cooked prior to consumption. However, thermal processing can cause over-softening of legumes. This study aimed to determine the effect of calcium addition (0, 100, 300, and 500 ppm in the form of calcium chloride, CaCl₂), starting from the overnight soaking step, in reducing the loss of firmness of black beans during thermal processing for up to 2 h. The impact of calcium addition on the in vitro starch and protein digestibility of cooked beans was also assessed. Two strategies of calcium addition were employed in this study: (Strategy 1/S1) beans were soaked and then cooked in the same CaCl₂ solution, or (Strategy 2/S2) cooked in a freshly prepared CaCl₂ solution after the calcium-containing soaking medium was discarded. Despite the texture degradation of black beans brought about by increasing the cooking time, texture profile analysis (TPA) revealed that their hardness, cohesiveness, springiness, chewiness, and resilience improved significantly (p < 0.05) with increasing calcium concentration. Interestingly, beans cooked for 2 h with 300 ppm CaCl₂ shared similar hardness with beans cooked for 1 h without calcium addition. Starch and protein digestibility of calcium-treated beans generally improved with prolonged cooking. However, calcium-treated beans cooked for 1 h under S2 achieved a reduced texture loss and a lower starch digestibility than those beans treated in S1. A lower starch digestion could be desired as this reflects a slow rise in blood glucose levels. Findings from this result also showed that treating black beans with high level of CaCl₂ (i.e., 500 ppm) was not necessary, otherwise this would limit protein digestibility of cooked black beans.

Soybean germination limits the role of cell wall integrity in controlling protein physicochemical changes during cooking and improves protein digestibility

Previous studies showed that in vitro digestibility of proteins in cooked beans is modulated by heat treatment and that the effect may be different whether proteins are heated in intact cotyledon or in a bean flour. In this study, germinated and non-germinated soybean cotyledons and flour were boiled at 100 °C for varying times (30, 90, or 180 min). After grinding, the level of trypsin inhibitors, protein aggregation, surface hydrophobicity, the secondary structure, and in vitro digestibility were studied. The presence of an intact cell wall during cooking increased protein denaturation temperature by about 10% and reduced the denaturation of trypsin inhibitors, and induced distinct changes in protein surface hydrophobicity and secondary structure. These physicochemical properties translated into an increment in protein degree of hydrolysis (DH, 72%) of protein cooked for 30 min as flour compared to proteins cooked in intact soybean tissues (64%). Increase in cooking times (90 and 180 min) resulted in limited improvement in the protein digestibility and changes in protein physicochemical properties for both boiled cotyledons and flour. Soybean germination resulted in distinct changes in protein physicochemical properties and higher protein DH% of raw soybean (61%) compared to non-germinated raw soybean (36%). An increase in protein digestibility of germinated soybean was also observed after boiling for both cotyledon and flour. However, significant differences in DH% were not observed between proteins boiled in intact cotyledon and in a flour. This work provides extra knowledge of the role of cellular integrity on protein properties in plant foods and suggests that germination or grinding before cooking may increase protein digestibility.

Investigation of process and product parameters for physicochemical properties of rice and mung bean (Vigna radiata) flour based extruded snacks

PR 106 and SML 668 cultivars of rice and mung bean respectively, were studied for their potential to serve as a nutritious snack with improved protein quality and quantity. The effect of extrusion conditions, including feed moisture content (14-18%), screw speed (400-550 rpm) and barrel temperature (130-170°C) on the physicochemical properties (bulk density, water absorption index (WAI), water solubility index (WSI) and hardness) was investigated. The replacement of rice flour at 30% level with mung bean flour for making extruded snacks was evaluated. Pasting temperature increased (84-93 °C) while peak viscosity (2768-408 cP), hold viscosity (2018-369 cP), breakdown (750-39 cP), setback (2697-622 cP) and final viscosity (4715-991 cP) decreased with increasing mung bean flour addition. Increasing feed moisture lowered the specific mechanical energy (SME), WAI and WSI of extrudates whereas increased bulk density and hardness. Higher screw speed had linear positive effect on SME of extruder and negative linear effect on WAI. Positive curvilinear quadratic effect of screw speed was also observed on WSI and density. Higher barrel temperature linearly decreased the SME, density and hardness of extrudates. Developed extrusion cooked rice-mung bean snacks with increased protein content and improved protein quality along with higher dietary fibre and minerals have good potential in effectively delivering the nutrition to the population.

Kinetic Stability of Proteins in Beans and Peas: Implications for Protein Digestibility, Seed Germination, and Plant Adaptation

Kinetically stable proteins (KSPs) are resistant to the denaturing detergent sodium dodecyl sulfate (SDS). Such resilience makes KSPs resistant to proteolytic degradation and may have arisen in nature as a mechanism for organismal adaptation and survival against harsh conditions. Legumes are well-known for possessing degradation-resistant proteins that often diminish their nutritional value. Here we applied diagonal two-dimensional (D2D) SDS-polyacrylamide gel electrophoresis (PAGE), a method that allows for the proteomics-level identification of KSPs, to a group of 12 legumes (mostly beans and peas) of agricultural and nutritional importance. Our proteomics results show beans that are more difficult to digest, such as soybean, lima beans, and various common beans, have high contents of KSPs. In contrast, mung bean, red lentil, and various peas that are highly digestible contain low amounts of KSPs. Identified proteins with high kinetic stability are associated with warm-season beans, which germinate at higher temperatures. In contrast, peas and red lentil, which are cool-season legumes, contain low levels of KSPs. Thus, our results show protein kinetic stability is an important factor in the digestibility of legume proteins and may relate to nutrition efficiency, timing of seed germination, and legume resistance to biotic stressors. Furthermore, we show D2D SDS-PAGE is a powerful method that could be applied for determining the abundance and identity of KSPs in engineered and wild legumes and for advancing basic research and associated applications.

Nutritional quality of microwave-cooked and pressure-cooked legumes

Eight whole legumes, namely Bengal gram (Cicer arietinum), broad beans (Vicia faba), Cowpea (Vigna catjang), field beans (Dolichos lablab), green gram (Phaseolus aureus Roxb), horse gram (Dolichos biflorus), lentils (Lens esculenta) and French beans (Phaseolus vulgaris), were cooked under pressure or in a microwave oven and were analysed for nutrient composition. Raw legumes served as control. The range of nutrients analysed in 100 g cooked samples were as follows: moisture, 62.8-69.7 g; protein, 14.7-24.3 g; fat, 0.9-5.9 g; ash, 1.7-4.6 g; iron, 3.3-8.6 mg; calcium, 50-209 mg; phosphorus, 249-429 mg; and thiamin, 0.14-0.32 mg. Cooking methods did not affect the nutrient composition of legumes. However, thiamine decreased in cooked samples. Cooking altered the dietary fibre content of some legumes. The mean in vitro protein digestibility of pressure-cooked and microwaved samples was 79.8% and 74.7%, respectively. The in vitro starch and protein digestibility of pressure-cooked samples were higher.