Produção e caracterização nutricional e tecnológica do amido de arroz vermelho modificado enzimaticamente.

Abstract

The objective of the present work was to produce and characterize the modified red rice starch through the enzymatic process. The enzymatic modification was performed sequentially through the actions of α-amylase enzymes and amyloglucosidase. The native and modified starches were characterized as physicochemical, physical, centesimal, bioactive, morphological, thermal, structural, texture and rheological properties. The effect of the addition of 10% of the flour of the jabuticaba bark on the texture and rheological properties of the starches was evaluated. The native starch presented 17.63% amylose, 63.92% amylopectin, high concentration of phenolic compounds, including anthocyanins (pink pigment), and its extraction process had yield of 69.14%. The enzymatic modification process resulted in 4.46% hydrolysis of the starch with the action of the α-amylase enzyme and 8.63% by the action of the enzyme amyloglucosidase, with 13.09% of total hydrolysis. The independent variables: pH, time and enzymatic loading were directly proportional to the starch modification process. The enzymatic modification process resulted in the reduction of the starch, amylopectin and syneresis content, also in the enthalpy parameters of gelatinization, firmness, guminess, cohesiveness, adhesiveness, tendency to retrograde and final viscosity, as well as the increase of water absorption , oil and milk, porosity at the surface of the granule, higher mass loss in the first two thermogravimetric events, crystallinity index, intensity of the characteristic peaks of the starch molecule and minimum viscosity. Addition of jaboticaba peel flour to the starches resulted in increased firmness, guminess, cohesiveness only for α-amylase-modified starch, adhesion only for native starch and decrease for tendency to retrograde, final viscosity and minimum viscosity. The starch obtained in the research, and its mixtures with jabuticaba peel flour, presented functional and technological properties, important for its use in the chemical and food industry, also generating, alternative for the production of new products for consumption by people with gluten restrictions and difficulty in deglutination.