USO DA FTIR ASSOCIADA A FERRAMENTAS QUIMIOMÉTRICAS NA AVALIAÇÃO DE GRÃOS DE FEIJÃO

Abstract

Beans are one of the most consumed foods in the world. In Brazil it is one of the most consumed foods. Due to its known flavor, beans are present in various recipes such as feijoada. In addition to the taste, this grain is also important due to its high nutritional value. Beans contain proteins, carbohydrates and fiber which are an important ally for health, helping to prevent chronic degenerative diseases such as diabetes, obesity, etc. Bean grain quality can be affected from planting to storage. Dietary fibers (soluble and insoluble) are an important parameter for verifying grain quality. In this work, 21 bean samples, obtained from the commerce of the cities of Ceres-GO, Carmo do Rio Verde-GO and Itapaci-GO, were analyzed. Fiber analysis was performed by Fourier Transformed Medium Infrared Spectroscopy (FTIR) in conjunction with the use of chemometric tools. In addition to the data pre-treatment step, a Principal Component Analysis (PCA) was applied. The extracted fiber levels were close to the values found in the literature (0.020g or 100g/kg sample and 0.045g or 225g/kg sample). Analyzing the spectra of the extracted fibers and the fresh bean grains, the characteristic functional groups of its composition were observed, such as, for example, in the wave number 3650-3600cm-1, a medium intensity stretch in the bond (OH). of phenols, at 2960-2840cm-1 função organic function O-CH3 symmetrical elongation vibration at bond (CH),  955-875cm-1 off-plane deformation of mean bond (OH). With the application of PCA it was possible to analyze the samples according to their similarities in the score graph, by forming clusters between samples that presents common characteristics, such as: class, type, amount of fiber extracted, and protein content. crude, carbohydrates and lipids. The analysis of extracted and fresh fiber spectra revealed the potentiality to apply FTIR in the study of insoluble and soluble fibers, without the need for extraction of insoluble ones.