Physicochemical Properties of Sweet Potato Starches

Abstract

The physicochemical properties of the starches from three varieties of sweet potatoes were investigated. The crystalline structures of Koganesengan and Minamiyutaka starches were of the A type and that of Norin‐2 starch was of the Ca type. Their amylograms showed pasting temperatures of 73–75°C and maximum viscosities of 500–580 BU. 3‐Methyl‐1‐butanol lowered their pasting temperatures without altering their maximum viscosities. The amylose and organic phosphorus contents of the starches were 17.2–19.0% and 117–139 ppm, respectively. The amyloses comprised branched molecules of average degree of polymerization 3400–4400 with 10–13 chains on average and were hydrolyzed 72–73% by β‐amylase. The main amylopectins had average chain lengths of 21–22, β‐amylolysis limits of 55–56% and organic phosphorus contents of 117–144 ppm, of which 75–81% was attached to C–6 of the glucose residue and the remainder to C–3. Another type of amylopectin (10–15% of the starch), which had higher iodine affinity, was isolated.

Composition and Structure of Starch from Taproots of Contrasting Genotypes of Medicago sativa L.

“…The ratio of low-to-high mol wt starch from taproots of the HSt genotype averaged 0.23 (Fig. 4) indicating that, like many other starches (1,7,17,27), the high mol wt component (amylopectin) comprised the majority of the starch in roots of this genotype. Contrary to our expectations, the ratio of low-to-high mol wt starch in taproots of the HSt genotype was constant even though a fourfold decrease in starch concentration occurred during the 7 d immediately after defoliation (Fig.…”

“…11,789. wt, highly branched) (28). Amylopectin typically constitutes 70 to 90% of starches from cereal grains, underground tubers, and roots (1,7,27). The composition of starch generally reflects differences in activities of enzymes involved in starch synthesis (22), and is known to vary among and within species (4,10,13).…”

Characterization of Physicochemical and Functional Properties of Starch from Five Yam (Dioscorea Alata) Cultivars in Indonesia

“…Blue Value at 680 nm was determined according to Noda et al [14] using intact starch rather than defatted starch. Amylose content was determined from Blue Value according to the equation of Takeda et al [15]. The BVs of amylose and amylopectin isolated from YS of 1.55 and 0.168, respectively, were determined by Suzuki et al [16].…”

Protein and starch characteristics of milled rice from different cultivars affected by transplantation date

“…Blue value, k max and amylose content Iodine absorption spectra and Blue Value (BV) of milled rice and starch were measured according to the method described by Takeda et al (1983). Amylose content (AC) of starch was determined by the method of Williams et al (1970).…”