Estudo do amido, proteína e compostos fenólicos do feijão Carioca

Abstract

Carioca beans are consumed daily in Brazil as a staple food by a large part of the population, due to its low cost and high nutritional value, as a source of protein and energy. This work aims to study the starch, protein and phenolic compounds of Carioca beans. The information obtained can led to an alternative to the use of depreciate grains due to the darkening, that occurs during storage under inadequate conditions, or due to aging. Three studies were conducted for the starch fraction: (1) using Campos Gerais cultivar samples, produced in different areas; (2) using Campos Gerais, Tangara, Estilo, Dama and ANFC cultivars, produced in a single area and (3) using Campos Gerais cultivar samples from different harvest. The starch was extracted by wet method. Amylose content, X-ray diffraction pattern, granule morphology, thermal transition of gelatinization, pasting properties, swelling power, solubility, syneresis and in vitro digestibility were analyzed. The amylose content ranged from 40.06 to 42.60%. The retrogradation, calculated using enthalpy of gelatinization and enthalpy of reassociation of starch, ranged from 45.7 to 59.3%. The samples showed high susceptibility to syneresis and low swelling power and solubility. The granular starch presented resistant starch content between 82.96 and 88.64%. The study of the Carioca bean protein consisted in the application of enzymatic hydrolysis at 6 and 9% degree of hydrolysis. The protein fractions of lower molar mass caused higher solubility, better emulsification and foaming properties. The study of these parameters was performed at pH value of 3.0, 5.0, 7.0 and 9.0. It was possible to demonstrate that the bean hydrolysate had superior characteristics to the soybean hydrolysate for the parameters: solubility, hydrophobicity, emulsification capacity and emulsifying activity. For the study of the phenolic profile of the Carioca bean, extraction methods were optimized using response surface methodology. The results antioxidant activity and phenolic compounds profile (high performance liquid chromatography) were analyzed by Principal Component Analysis. The extractions with 70% acetone and 50% methanol were more effective in the extraction of flavonoids and phenolic acids, respectively. The presence of kampferol and chlorogenic acid in Carioca beans was evidenced. The study of Carioca beans allowed a better global comprehension of the characteristics of this legume to allow the use of excess production and grains of old crops by the food industry.