Morphological changes of blocklets during the gelatinization process of tapioca starch

• Published in: Carbohydrate polymers Vol. 163; pp. 324 - 329
• Main Authors: Huang, Junrong, Wei, Maomao, Ren, Ruizhen, Li, Hongliang, Liu, Shuxing, Yang, Daqing
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2017
• Subjects: Blocklets; Enzymolysis; Gelatinization; Gels - chemistry; Hydrolysis; Manihot - chemistry; SEM; Starch - chemistry; Tapioca starch; Temperature; Blocklets; SEM; Gelatinization; Tapioca starch; Enzymolysis
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2017.01.083

•A method to interrupt the gelatinization process of starch was established.•Swollen blocklets deformed to form bead-like structure, and network structure in the end.•Morphological changes of the blocklets were not simultaneously.•A schematic diagram was presented for the morphological changes of blocklets. After combined hydrolysis by α-amylase and β-amylase at room temperature, spherical blocklets in diameters of 27–60nm were observed on the surface of tapioca starch granules by scanning electron micrography (SEM). Tapioca starch (1%, w/w, db, distilled water) was heated by using a rapid visco analyzer (RVA) in four different programs, then the samples were settled and freeze dried, respectively. The SEM images showed that the blocklets swelled at 52°C; the swollen blocklets deformed to olive shape, and linked by molecular chains, formed bead-like structure at 62°C; they started to merge at 72°C (pasting temperature); then the blocklets fused together and their shapes disappeared completely, and the gel network formed at 95°C. Furthermore, the morphological changes of the blocklets were not simultaneously.