Desempenho de genótipos de soja tipo-alimento de tegumento colorido em cultivo orgânico e convencional e aplicação de grãos como conservas e drageados

Abstract

The soybean [Glycine max (L.) Merrill] of colored tegument (yellow, brown and black) is indicated for human consumption and has been genetically improved, aiming at adding flavor, palatability and productivity. However, the food-type soybean market, as well as those of brown and black teguments are recent in Brazil. Consequently, soy-based food can be seen as an opportunity for the consumer market, as well as for the food industry. The objective of this work was to know more about these materials, regarding their productive performance in the organic and conventional systems in the Cerrado, and also to obtain information about their nutritional, functional, microbiological and sensory acceptance potential after canning and dragee processing. In the cultivation of organic soybean, twelve genetic materials were evaluated for the physiological, sanitary and chemical characteristics, being seven yellow tegument materials, two brown and three black. In conventional soybean cultivation, four materials were evaluated for their adaptation to the agronomic characteristics, physiological and sanitary qualities of the seeds. Food-type soybeans were evaluated with yellow, black and brown teguments, processed as preserves and as chocolate dragees. For all preserves, the objective was to verify the effect of maceration time and acid concentration. For the yellow soybean, the acetic acid was used in the brine (in relation to the grain mass) and for the brown and black soya beans, ascorbic acid. The effect was evaluated on the physical characteristics of the soybean preserves, through response surface methodology and composite central rotational design. In addition to evaluating the chemical, microbiological and sensorial characteristics of the selected preserve. For all reasons, the objective of this study was to evaluate the effect of the time of roasting in the microwave and the size of the grains of the food-type soybean for all the colors of tegument, yellow (BRSMG 790 A), black (line DF 06-81-1) and brown (BRM line 04-4382-4), yield, instrumental hardness, crispness and flavor of the toasted soybean core. In relation to the soybean cultivated in the organic system, nine of the evaluated genetic materials had good biological characteristics for soybean grain-type, with mass values of 1000 grains between 200 and 254 g. The genotypes presented satisfactory levels of protein between 37.4 and 43.1 g 100 g-1 (dry basis), and of isoflavones, between 101.8 and 190.8 mg 100 g-1 (defatted sample). The colored genotypes selected from organic cultivation and multiplied in the conventional system were yellow (BRSMG 790A), black (line DF 06-81-1) and brown (BRM 04-4382-4). These presented a cycle of 130 days and the height of the plant was considered adequate for mechanical harvesting. The BRM 04-4382-4 line showed the best results for height of insertion of the first pod (17.3 cm), number of pods with three grains (13.8 units), and stand on maturation of 14.9 plants per linear meter. The cultivar BRSMG 790A showed good adaptation to the region of Goiânia-GO, with a yield higher than those observed in Minas Gerais. As for processed grains, the presence of acetic acid in brine was detrimental to the quality of the yellow soybean preserves (BRSMG 790A). In contrast, the maceration time increased the moisture content and reduced the hardness of the grains. The preserve produced with maceration time of 100 min and zero concentration of acetic acid were selected, which presented lower hardness and loss of total solids in cooking water and higher content of total phenolic compounds and moisture in the grains. In this condition they 36 obtained values of 15.5 g 100 g-1 for protein and 7 g 100 g-1 for lipids. In both preserves the essential amino acid profile was not greatly affected by the processing, presenting amounts equivalent to that required as daily intake of children and adults. The selected yellow soybean preserved 36.8% of the antioxidant activity of the grains in natura. The preservation of black soybeans (line DF 06-81-1) and brown (BRM 04-4382-4) were favored by the ratio of maceration time and concentration of ascorbic acid in the brine, also presenting low loss of phenolic compounds in relation to the contents obtained in natura grain. The selected preserves of each color were obtained with maceration time of 50 min and ascorbic acid concentration of 0.15 g 100 g -1 , but for anthocyanin contents there were 100% losses, suggesting new studies for thermal treatments. As for the selection of the roasted core in microwaves, the best scores (flavor, crispness and hardness) were obtained for the large size grains (sieve 15) for all selected genetic materials. Resistant starch was not detected. But high levels of proteins and lipids were detected. All soybean preserves and dragees (yellow, brown and black) obtained were microbiologically stable products and had good sensory acceptance. Therefore, it can be concluded that the food-type soybean of tegument color can be grown in the cerrado, as well as its applicability, as soybean preserves and as chocolate soybeans dragees, because they have high potential of commercialization and are technologically viable.