Influence of molecular structure on the susceptibility of starch to alpha-amylase

Autor(es)

Villas-Boas, Flavia ^[1] ; Yamauti, Yasmin ^[1] ; Moretti, Marcia M. S. ^[1] ; Franco, Celia M. L. ^[1]

Afiliação do(s) autor(es)

^[1] UNESP Sao Paulo State Univ, Dept Food Engn & Technol, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Carbohydrate Research; v. 479, p. 23-30, JUN 1 2019.
• Citações Web of Science: 1

Resumo

The effect of the molecular structure of sweet potato (SPS), cassava (CAS) and high amylose maize (HAS) starches on the susceptibility to fungal and maltogenic alpha-amylases was investigated. The logarithm of the slope (LOS) and non-linear least-squares (NLLS) methods were used for fitting hydrolysis kinetics data. The malto-oligosaccharides released during hydrolysis were quantified and the hydrolysis residues were analyzed. The hydrolysis kinetic curves were well fitted to the LOS and NLLS models. SPS, CAS and HAS were hydrolyzed in one single phase by fungal alpha-amylase while two hydrolysis phases were identified for the root starches and a single phase for HAS, when maltogenic alpha-amylase was used. The lowest percentage of residual starch was found for CAS, independent of enzyme source, due to the high proportion of amylopectin short chains in this starch. On the other hand, the high proportion of HAS long chains contributed to its increased starch degradation rate coefficient during fungal alpha-amylase hydrolysis, while the high amylose content favored the endo-action pattern of maltognic alpha-amylase. Independent of starch source, malto-oligosaccharides of different sizes, especially G2-G5, were released after the fungal alpha-amylase action which hydrolyzes mainly inner and long amylopectin chains. Mainly maltose was produced in the maltogenic alpha-amylase hydrolysis which breaks the outer amylopectin chains by exo-action and amylose chains by endo-action. The starch molecular structure strongly interferes in both enzyme susceptibility and the action mechanism, as well as in the distribution and amount of products released. (AU)

• Processo FAPESP: 17/19521-1 - Efeito de tratamentos enzimático, químico e físico na estrutura, digestibilidade e potencial efeito prebiótico de amidos retrogradados
• Beneficiário: Celia Maria Landi Franco
• Modalidade de apoio: Auxílio à Pesquisa - Regular