Relationships between enzymatic hydrolysis conditions and properties of rice porous starches

Porous starches are attractive materials considered for use as bioadsorbents in food and non-food applications. Rice starches with different amylose content were treated with alpha-amylase and amyloglucosidase at 50 degrees C for 3 and 6 h. The morphology and dimensions of porous starches were determined by microscopy, while the granular structure was investigated by analysis for damaged starch and amylose content, spectroscopic and thermal techniques. In this paper, the relationships between extrinsic and intrinsic factors on porous starch properties were evaluated and the results showed that the enzyme type and amylose content have a substantial impact on the properties of the obtained porous starches, which were independent of reaction time. Statistical analysis revealed a positive and strong relationship between mean diameter with relative crystallinity and gelatinization temperatures, amylose content with gelatinization enthalpy, damaged starch with peak and conclusion temperatures, and relative crystallinity with gelatinization temperatures. On the other hand, a negative and strong correlation was identified between mean diameter and gelatinization enthalpy, amylose content and relative crystallinity and gelatinization temperatures, and relative crystallinity and gelatinization enthalpy. The relationships between properties and structure found in this research allow properties modulation according to the desired application and may be of great industrial interest.