The goal of this research is to determine the effects of added soybean lipoxygenase (LOX) on bread dough rheological properties and physical properties of bread loaves compared to controls, and to determine sensory attributes of bread loaves using quantitative descriptive analysis (QDA). Protein fractions were obtained through the use of isoelectric precipitation. The pH 4.8 precipitate was found to yield the greatest LOX activity when compared with other fractions (p<0.05). The addition of pH 4.8 precipitate improved rheological properties of bread dough, examined in a farinograph, when compared to the all-purpose control (p<0.05). Addition of soy flour also increased the gluten strength of all-purpose flour (p<0.05). The addition of pH 4.8 precipitate to all-purpose flour did not improve bread loaf volume or texture. Sensory panelists described pH 4.8 supplemented bread as having firmer crumb when compared with controls (p<0.05). There were slight color differences among the loaves. The crust and crumb of bread flour loaves was lighter in color than any other sample. It was concluded that the addition of pH 4.8 precipitate to all-purpose flour greatly improved the rheological properties when compared with all-purpose flour alone. / Master of Science

Soy flour was inoculated with Lactobacillus delbrueckii ssp. lattis R0187, and incubated for 8 h, to evaluate the protein hydrolysis and identify peptides generated by this fermentation, and the impact on ACE and trypsin inhibitory activities. Aqueous protein extracts prepared from different fermentation time periods showed a decrease in soluble protein content (from 2.83 to 0.02 mg/mL), while soluble inorganic nitrogen and free amino acid contents increased (from 0.029 to 0.062% w/w, and from 0.75 to 0.90% w/w, respectively). The protein extracts were analyzed by SDS-PAGE; proteolysis was observed after 5 h incubation of inoculated soy flour, suggesting that glycinin, beta-conglycinin, and trypsin inhibitors, were hydrolyzed. Peptides were isolated by tricine-SDS-PAGE, and analyzed by MS/MS; fragments of soy anti-nutritional factors (Kunitz and Bowman-Birk trypsir, inhibitors), as well as of other soybean proteins, were identified, confirming that these proteins were hydrolyzed. The protein extracts at time 0 h and 8 h were analyzed by RP-HPLC; one fraction was analyzed by MS/MS, which identified peptides from Lactobacillus species. Determination of trypsin inhibitory activity showed less inhibition of the enzyme with inoculated soy flour compared to the control (un-inoculated soy flour), confirming the deactivation of trypsin inhibitors by fermentation. Determination of ACE inhibitory activity showed a higher inhibition with the control (86% +/- 3.0) compared to inoculated soy flour (66% +/- 7.6).

Neste trabalho, foram estudadas a possibilidade e os benefícios na aplicação da farinha de tempeh como substituinte parcial da farinha de soja integral. Para isto, inicialmente foram avaliados a composição proximal e os teores de isoflavonas (agliconas e totais) nas farinhas de soja integral e de tempeh. Foram utilizados grãos de soja das cultivares BRS 216, BRS 257 e BRS 267, a fim de verificar as alterações causadas pela fermentação com o fungo Rhizopus oligosporus, utilizado para obtenção do tempeh, e o efeito dos processos de secagem por torra controlada e liofilização sobre a farinha final obtida. Os resultados obtidos das farinhas de tempeh demonstraram um aumento nos teores de proteínas para todas as cultivares, com destaque para a BRS 216, que obteve valores finais de 57,36 g.100g-1 e 59,30g.100g-1 nos tempeh torrado e liofilizado, respectivamente. Foi verificada também redução dos teores de carboidratos totais, causada principalmente pela solubilização em água durante o processo de obtenção do tempeh, e uma elevada taxa de conversão dos compostos isoflavonóides, com aumento dos teores de agliconas (formas ativas para o organismo humano) para o tempeh liofilizado e torrado em todas as cultivares avaliadas, tendo a BRS 267 obtido o maior teor final de agliconas. Por esta razão, a BRS 267 foi escolhida para obtenção das farinhas mistas de soja e tempeh torrado/liofilizado, e para os testes de formulação do biscoito, que foi avaliado quanto à composição proximal, teor de agliconas, perfil de ácidos graxos e testes sensoriais de aceitação e intenção de compra. Os resultados desta segunda etapa comprovaram a manutenção do teor de ácido linolênico, importante para redução dos riscos de doenças coronarianas, além do ganho nos teores de agliconas quando utilizada a farinha de tempeh. Houve também alterações nos teores de proteínas e lipídios e, nos testes sensoriais, ficou evidenciada a semelhança entre as formulações, com notas satisfatórias para os atributos de aroma, sabor, textura e aceitação global dos biscoitos com farinha de soja e tempeh, quando comparadas ao biscoito contendo apenas farinha de soja. A intenção de compra também foi positiva, o que indica a torra como processo simples e economicamente viável para processamento do tempeh, e obtenção de uma farinha rica em proteínas e isoflavonas agliconas, que pode ser empregada como substituinte parcial à farinha de soja em biscoitos e outros produtos de panificação. / In this study, the benefits and application of tempeh flour as an alternative for soybean flour were evaluated. In the first stage, proximal composition, aglycone and total isoflavone content were analyzed in the soybean and tempeh flour. Grains of cultivars BRS 216, BRS 257 and BRS 267 were tested, in order to verify the effects of Rhizopus oligosporus, which is used for tempeh fermentation, plus the drying methods of controlled toasting and lyophilization, over the final flour. The results for tempeh flour showed an increase in protein content for all the cultivars, especially for BRS 216, which presented final values of 57.36g.100g-1and 59.30g.100g-1 for toasted and lyophilized tempeh flour, respectively. Total carbohidrates presented a reduction for all cultivars, mostly due to water solubilization during the process for tempeh preparation, and the isoflavone content showed a high conversion rate, with gains in aglycone levels (active forms for human consumption) for all lyophilized and toasted tempeh flours. BRS 267 showed the higher values for aglycone, reason to be chosen for the second part of the study, when mixed flour of soybean and lyophilized/toasted tempeh flour were obtained and applied in the formulation of coconut biscuits, which were evaluated for proximal composition, aglycone content, fatty acid profile and affective sensory analyses. Use of tempeh flour caused increase in aglycones level while linolenic acid content remained stable, which is important to reduce risks of coronary diseases. Lipids and protein contents also showed differences, and the sensory analysis demonstrated similarity between the biscuits, with satisfactory scores in aroma, flavor, texture and overall acceptability for cookies containing soy and tempeh flour, when compared to the cookie formulated with soy flour only. Purchase intention was also positive for both, which indicates roasting process, a simple and economically feasible drying method, for processing tempeh to a flour. This ingredient, rich in protein and aglycone isoflavones, important for human health, can be used as a partial substitute for soybean flour in cookies and other bakery products.