O feijão (Phaseolus vulgaris L.) é um alimento básico na refeição do brasileiro, constituindo uma das principais fontes proteicas da dieta, além de fornecer outros macronutrientes e minerais. Apesar da considerável concentração de proteínas no feijão, este alimento é considerado de baixo valor biológico, quando comparado a proteínas animais e a outras fontes proteicas vegetais. Visando melhorar a disponibilidade proteica do feijão, foram realizados tratamentos enzimáticos em quatro cultivares de feijão (ON; OPNS, TAL e VC3). O delineamento foi inteiramente casualizado, em fatorial 4 × 3 (quatro cultivares e três tratamentos: testemunha, sem protease; hidrolisado 1, adição de protease comercial (Trypsin 250, Difco); hidrolisado 2, adição de protease de Bacillus sp.) com 4 repetições. A relação enzima:substrato foi 5% (m/m, considerando a quantidade de proteínas totais nas amostras de farinha). A concentração de proteínas totais (g.100 g-1 de matéria seca) nas amostras variou de 16,94 a 18,06%, enquanto a concentração de fenólicos totais esteve entre 0,78 e 1,12% (g Eq. ácido tânico.100 g-1 de matéria seca). A digestibilidade protéica in vitro na farinha não tratada enzimaticamente (testemunha) variou entre 47,30 e 56,17%, em relação à digestibilidade da caseína. As concentrações de P, K, Ca, Mg, S e Zn observadas nas quatro cultivares testadas se encontram dentro dos valores médios disponíveis na literatura. No tratamento com protease de Bacillus sp., houve diminuição nos teores de Cu e Mn. O teor médio de Fe aumentou nas farinhas tratadas enzimaticamente, chegando ao incremento máximo de 102% para a farinha da TAL tratada com protease de Bacillus sp. A digestibilidade de todas as farinhas testadas aumentou significativamente (p < 0,05) em função do tratamento enzimático. A maior variação foi observada na cultivar OPNS, cujos valores, respectivamente, para a testemunha e protease de Bacillus sp. , foram 54,4 e 81,6%.
The common bean (Phaseolus vulgaris L.) is a staple food in the Brazilian diet and represents the major source of dietary protein and other micronutrients and minerals. Despite the considerable protein concentration in beans, the food is considered of low biological value when compared to animal proteins and other plant protein sources. To improve the availability of protein in beans, enzymatic treatments were performed in four cultivars (ON, OPNS, TAL and VC3). The approach was a completely randomized design with four replicates. We used a 4 × 3 factorial arrangement (four cultivars and three treatments: treatment 1-addition of commercial protease (Trypsin 250, Difco), treatment 2-addition of protease from Bacillus sp., and treatment 3:-control without enzyme addition). The enzyme: substrate ratio was 5% w/w (amount of enzyme per total protein in bean flour). The approach was a completely randomized design with four replicates. A 4 × 3 factorial arrangement (four cultivars and three treatments, the same as those mentioned above) was used. The concentration of total protein (g.100 g-1 of dry matter) in the samples ranged from 16.94 to 18.06%, while the concentration of total phenolics was between 0.78 and 1.12% (g Eq. tannic acid.100 g-1 dry matter). The in vitro protein digestibility of enzymatically untreated bean flour (control) ranged from 47.30 to 56.17% based on the digestibility of casein. Concentrations of P, K, Ca, Mg, and Zn observed in the four cultivars tested were within the average values available in the literature. Treatment 2 with protease from Bacillus sp. induced decreases in the levels of Cu and Mn. The average Fe content increased in all bean flour samples when treated with proteases, reaching a maximum increase of 102% in the TAL flour treated with protease from Bacillus sp. The digestibility of all beans tested was significantly increased (p < 0.05) after the enzyme treatment. The greatest change was observed in the OPNS cultivar treated with protease from Bacillus sp., which increased its digestibility from 54.4% (control treatment) to 81.6%.