A further understanding of the multi-scale supramolecular structure and digestion rate of waxy starch. (April 2017)

• Record Type: Journal Article
• Authors: Qiao, Dongling; Xie, Fengwei; Zhang, Binjia; Zou, Wei; Zhao, Siming; Niu, Meng; Lv, Rui; Cheng, Qian; Jiang, Fatang; Zhu, Jie
• Is Part Of: Food hydrocolloids. Volume 65(2017)
• Page Start: 24
• Page End: 34
• Publication Date: 2017-04
• Subjects: Starch -- Multi-scale -- Supramolecular structure -- Digestion rate; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2016.10.041
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: This work concerns how the multi-scale supramolecular structure of starch relates to its digestion rate from a view of structural heterogeneity. The untreated granule starch displayed a dual-phase digestion pattern, ascribed to two digestible fractions within the heterogeneous multi-scale structure of starch, which had prominently different digestion rates. Not only amorphous starch but also part of molecular orders (crystallites with flaws) were digested at a same rate k 1 at the first phase; densely-assembled starch including orders with fewer flaws was digested at a rather slow rate k 2 ( ca . 2/5 of k 1 ) at the second phase. When alkali altered the heterogeneous supramolecular structure of starch, the digestion behaviors were also changed. The 0.1% (w/v) alkali solution slightly disrupted the starch multi-scale structure, which reduced the molecular orders, disrupted the lamellae, weakened the molecular organization within growth rings, and enlarged the granule pores. Then, part of resistant starch was transformed into slowly-digestible fraction with a digestion rate close to k 2 . In contrast, when stronger (0.5% w/v) alkali was used, the starch multi-scale structure was more apparently disrupted, causing even granule swelling. This structural change resulted in a triple-phase digestion with three different digestion rates. Moreover, especially with stronger alkali, along with the structural disruption, some orders with a higher thermal stability emerged and reduced the accessibility of starch molecules to the enzyme. In this case, the digestion rate decreased with the treatment time. Graphical abstract: Highlights: Relation between supramolecular structure and digestion rate was further disclosed. Untreated starch had two digestible fractions with different digestion rates. Amorphous starch and partial orders could be digested at a same rate. Multi-scale structural changes induced by alkali altered starch digestion date.