Secagem e processamento de genótipos de milho: efeitos sobre as propriedades físico-químicas e tecnológicas do amido e do óleo

Abstract

In the food industries, starch and oil are the main products derived from corn grains. The changes in the physicochemical and technological properties of starch and oil occur due to the conditions of drying and processing, which has been the subject of studies. The present study was divided into two studies and aimed: evaluate the effects of drying temperature (30, 50, 70, and 90 ºC) and genotype (farinaceous yellow, farinaceous white, and semi-hard yellow striped) on the morphology, pasting and thermal properties of the corn starch; and evaluate the effects of waiting time for germ oil extraction (0, 30, and 60 days) and genotype (farinaceous yellow, farinaceous white and semi-hard yellow) on corn oil quality. The genotypes of farinaceous yellow (CMST 029), farinaceous white (BRS 015FB), semi-hard yellow striped (CMST 012), and semi-hard yellow (BRS 022SE) were used. Farinaceous white corn presented the higher starch extraction yield, followed by farinaceous yellow and semi-hard yellow striped. The starch extracted from the white farinaceous genotype showed higher resistance during granules swelling before the physical collapse, as it was not affected by the drying temperature increase and at 90 ºC presented the higher breakdown and higher energy required for gelatinization. Palmitic, stearic, oleic, linolenic, arachidonic, and cis-11-eicosenoic acids, δ-tocopherol, γ-tocopherol, and αtocopherol, lutein, zeaxanthin, β-cryptoxanthin, and β- carotene were observed. In this study, after 30 days of delay for the extraction of corn germ oil, there was an increase in acidity and lipase activity. After 60 days, the semi-hard yellow corn oil showed lower acidity and lipase activity, and the higher amount of lutein, zeaxanthin, β-cryptoxanthin, and β-carotene.