Márcia Regina Pereira Monteiro

Qualidade protéica de linhagens de soja com ausência do Inibidor de Tripsina Kunitz e das isoenzimas Lipoxigenases

OBJECTIVE: The objective of this work was to evaluate the protein quality of soybean flours that differs from each other in relation to the presence of lypoxigenases and/or Kunitzs Trypsin Inhibitor. METHODS: Biological assays with rats were carried out to evaluate Protein Efficiency Ratio, Net Protein Ratio, Net Protein Utilization and the digestibility. The determination of the aminoacid composition of the flours and the estimation of Chemical Score Corrected by Digestibility were carried out. RESULTS: The Protein Efficiency Ratio, Net Protein Ratio, Net Protein Utilization values for the soybean varieties were inferior to the values obtained for casein. Higher digestibility values were obtained for the flours lacking Kunitzs Trypsin Inhibitor than for the flours with Kunitzs Trypsin Inhibitor present, and those were very close to the values of casein. About the determination the aminoacid composition it was verified that the restraining amino acid of this soybean is lysine, not methionine, differently from what literature indicates. CONCLUSIONS: The genetic removal of Kunitzs Trypsin Inhibitor improves soybean protein digestibility considerably. Chemical Score Corrected by Digestibility results did not indicate difference between the flours lacking Kunitzs Trypsin Inhibitor and those derived from flours of lines with Kunitzs Trypsin Inhibitor present, as it was observed by the results of in vivo digestibility.

Qualidade protéica de multimisturas distribuídas em Alfenas, Minas Gerais, Brasil

OBJECTIVE: The study was developed to evaluate the protein quality of four multimixtures distributed in communities in Alfenas, MG, Brazil, to combat malnutrition. METHODS: Male Wistar rats were randomaly assigned to one of six groups (n=6) and individually housed in stainless steel cages on controlled temperature (25oC, standard deviation 2oC) for 14 days. The standard group was fed a casein diet, control group was fed a free nitrogen diet and four-test groups were fed different multimixture diets. A biological assay was carried out to determine the protein quality by Protein Efficiency Ratio, Net Protein Ratio, Net Protein Utilization and True Protein Digestibility. RESULTS: The Multimixture test groups showed lower (p<0.05) Protein Efficiency Ratio, Net Protein Ratio and digestibility than casein group. The net retention protein from multimixture test groups was lower (p<0.05) than casein group, except the group fed with multimixture contained a higher powdered milk proportion and was not added with powdered seeds, leaf cassava and egg shell powders in their formula. The multimixture digestibility was roughty 89% however the protein retention was approximately 27%. CONCLUSION: In conclusion, the multimixture showed low protein retention, did not promote adequate animal growth and was not capable of maintaining body weight in one multimixture test-group.

Evaluation of the chemical composition, protein quality and digestibility of lupin (Lupinus albus and Lupinus angustifolius)

The purpose of this study was to determine the protein quality of lupin (Lupinus albus and Lupinus angustifolius) and to determine their chemical composition, including dietary fiber. The food transformation index, protein efficiency ratio and net protein ratio were significantly higher for the casein group than for the lupin groups. The in vivo digestibility value of casein was 95.81 ± 1.60, and the DV of L. albus and L. angustifolius were 90.89 ± 2.85 and 89.30 ± 2.01, respectively. Amino acid composition scores lower than one were found for almost all essential amino acids in lupin groups. The protein digestibility corrected amino acid scores ranged from 40.00% to 89.07% for L. albus and from 30.36% to 83.05% for L. angustifolius. It was concluded that the two varieties of lupins studied are good protein sources, with no statistical difference between them, and also that this protein has an excellent digestibility, besides being a good source of dietary fiber, especially Lupinus angustifolius. Therefore, the two varieties of lupine were considered as having good quality protein and as being a good alternative for human consumption.