Influência das variáveis de parboilização sobre as características químicas, tecnológicas e de cocção do arroz vermelho.

Abstract

This study aims to evaluate the characterization of fresh red rice, red hydrated red rice for 7 hours at temperatures of 45 to 75°C and parboiled rice autoclaved for 14, 22 and 30 minutes, also submitted to drying at temperatures. 50, 60 and 70 ° C by the following analyzes: centesimal characterization, starch content, thermogravimetry (TG), Fourier Transform Infrared Spectroscopy (FTIR-ATR) and Scanning Electron Microscopy (SEM), as well as analyzing the absorption kinetics at temperatures of 45, 55, 65 and 75 °C, according to Peleg Models (1988), the models proposed by Cavalcanti Mata & Duarte (2018) and Duarte & Cavalcanti Mata (2018). Parboiled rice drying kinetics were also analyzed for autoclave times 14, 22 and 30 minutes and drying temperatures 50, 60 and 70 °C.The texturometric parameters, such as, firmness, cohesiveness, stickiness, gomosity and chewability of parboiled rice were also evaluated. It was concluded that the analysis of centesimal composition and characterization of starch content of parboiled red rice with autoclave time 14, 22 and 30 minutes submitted to drying at 50°C observed values corresponding to the values of parboiled rice of other literatures. Mathematical modeling revealed that Cavalcanti Mata & Duarte (2018) and Duarte & Cavalcanti Mata (2018) models compared to Peleg (1988) models were better to describe the hydration kinetics of husked red rice, evaluated by statistical parameters. R2 , P, DQM and SE. From the characterization by TG the percentage of mass and the degradation temperature range of the polysaccharides of hydrated red rice were obtained. The FTIR analysis showed characteristic bands of type A starch for hydrated rice. In the micrographs, it was observed that the red rice in shell had altered its morphological structure. Degradation temperatures and DTG yield provided the values at which dehydration phenomena occur and the degradation events of parboiled red rice polysaccharides. The FTIR analysis confirmed the modification in the chemical structure of the parboiled rice starch, since the characteristic bands for the starch corresponding to the CH, CO and C-OH strains and the bands corresponding to the deformations C = O, C-OH and CH2, as well as the vibrations of the COC and CO groups in alcohols, their bands in relation to the characteristic bands of fresh red rice were reduced. SEM analysis of autoclaved parboiled rice for 14, 22 and 30 minutes and submitted to drying temperatures of 50, 60 and 70 °C also showed starch gelatinization. From the drying process, Cavalcanti Mata's Model I was the best, through the evaluation of statistical parameters R2 , P, DQM and SE. The mathematical model evaluated for the texturometric parameters: firmness, cohesiveness, adhesiveness, guminess and chewability were considered satisfactory by the statistical parameters R2 , P, DQM and SE.