Effects of Amylopectin Branch Chain Length and Amylose Content on the Gelatinization and Pasting Properties of Starch

Abstract

Cereal Chem. 76(5):629-637Structures and properties of starches isolated from different botanical sources were investigated. Apparent and absolute amylose contents of starches were determined by measuring the iodine affinity of defatted whole starch and of fractionated and purified amylopectin. Branch chainlength distributions of amylopectins were analyzed quantitatively using a high-performance anion-exchange chromatography system equipped with a postcolumn enzyme reactor and a pulsed amperometric detector. Thermal and pasting properties were measured using differential scanning calorimetry and a rapid viscoanalyzer, respectively. Absolute amylose contents of most of the starches studied were lower than their apparent amylose contents. This difference correlated with the number of very long branch chains of amylopectin. Studies of amylopectin structures showed that each starch had a distinct branch chain-length distribution profile. Average degrees of polymerization (dp) of amylopectin branch chain length ranged from 18.8 for waxy rice to 30.7 for high-amylose maize VII. Compared with X-ray A-type starches, B-type starches had longer chains. A shoulder of dp 18-21 (chain length of 6.3-7.4 nm) was found in many starches; the chain length of 6.3-7.4 nm was in the proximity of the length of the amylopectin crystalline region. Starches with short average amylopectin branch chain lengths (e.g., waxy rice and sweet rice starch), with large proportions of short branch chains (dp 11-16) relative to the shoulder of dp 18-21 (e.g., wheat and barley starch), and with high starch phosphate monoester content (e.g., potato starch) displayed low gelatinization temperatures. Amylose contents and amylopectin branch chain-length distributions predominantly affected the pasting properties of starch. MATERIALS AND METHODS MaterialsChinese taro, mung bean, waxy rice, sweet rice, green leaf canna, lotus root, water chestnut, and cattail millet starches were isolated in the laboratory as reported by Lim et al (1994). Waxy amaranth I was isolated by the alkaline method (Myers and Fox 1994). Waxy amaranth II and normal glacier barley starch were isolated by a combination of mild alkaline and protease treatments (Radosavljevic et al 1998). Green banana starch was provided by A. R. Bonilla, University of Costa Rica. Waxy maize, amyloseextender (ae) waxy and dull (du) waxy maize starches were gifts of Cerestar, USA (Hammond, IN); potato and wheat starches were purchased from Sigma Chemical Co. (St. Louis, MO);

Nanostructural Morphology of Plasticized Wheat Gluten and Modified Potato Starch Composites: Relationship to Mechanical and Barrier Properties

“…A higher amylose content and longer chain-length of amylopectin are known to affect pasting properties. 27 The results in this study confirmed the altered molecular structure seen by gel permeation chromatography.…”

Effect of pulsed electrical fields on the structural properties that affect french fry texture during processing

“…The low gelatinization of potato starch is considered to be partly due to the higher levels of phosphate monoester derivatives compared to starches found in grains, and the abundance of the B-type crystalline structures (Jane et al, 1999). The negative charges of the phosphates adjacent to the amylopectin chains repel each other, weakening the hydrogen bonds in the crystalline structure.…”

“…The negative charges of the phosphates adjacent to the amylopectin chains repel each other, weakening the hydrogen bonds in the crystalline structure. These weakening bonds then allow water to readily destabilize the granular structure, reducing the gelatinization temperature (Jane et al, 1999). The B-type structure is characterized by a large proportion of long amylopectin branches (Gilbert, Besnard, Reeve, Lambides, & Hasjim, 2013) and fewer short branches (Hizukuri, Takeda, & Yasuda, 1981).…”

Physicochemical Characteristics of Starches in Rice Cultivars of Diverse Amylose Contents

“…In particular, it is one of the most important rheological indicators of the cooking quality and processing characteristics of rice. The amylose content and branch chain length distribution have also been found to have a substantial impact on the swelling and pasting properties of rice starches (Tsai et al, 1997;Jane et al, 1999). To examine the gelatinization characteristics of the four rice cultivars under analysis in this study, the swelling and thermal properties of their starches were measured using method of Li and Yeh (2001) and a differential scanning calorimeter, respectively.…”

“…Moreover, gelatinization in this cultivar was complete at about 100℃ and occurred over a range that is 10℃ higher than that of the other starches. Jane et al (1999) have reported that the chain length and distribution of amylopectin branches determines the gelatinization temperature of starch, in addition to the enthalpy changes, and pasting properties, and that this temperature increases with the interactions between longer chains within the amylopectin cluster. The gelatinization enthalpy (∆H), which is the energy required to melt rice starches, showed energy content differences ranging between 7.4 and 8.8 J/g, and was found to be highest in Ilpum.…”