Effect of enzymatic treatments on thermal, rheological and structural properties of pinhao starch

Abstract Pinhao is the seed from Araucaria angustifolia. The composition of these seeds shows high carbohydrate levels (≅70% of dry matter) and low values of lipids, proteins and fibres. Starch in its original state usually does not attend industry demands, such as low retrogradation and high thermal stability. Therefore, its modification is an option to improve its properties and has more potential usage. An alternative to chemical modification is utilising enzymes such as α-amylase and glucoamylase, to enhance starch characteristics and be less aggressive to the product and environment. After the enzymatic modification, in different times (12, 24 and 36 h at 31 °C). Higher parameters for gelatinisation in DSC were observed. The TG showed similarity in all curves with three mass losses. RVA profiles showed a decrease in peak viscosity. The XRD diffractograms indicated a decrease in relative crystallinity and there was alterations in granules surface structure by SEM images due to the enzyme action.