Ultrasound Assisted Extraction of Yam (Dioscorea bulbífera) Starch: Effect on Morphology and Functional Properties

Abstract

After the grinding stage of yam tubers, ultrasonic treatment (UT) is compared to traditional starch extraction. Different sonication conditions of amplitude (12, 40, and 68%) and time (3, 6, and 9 min) are evaluated along two other treatments: a control (0% amplitude) and 70% amplitude for 15 min, in order to compare the traditional extraction method and extreme ultrasonic conditions. Extraction yield, centesimal composition, color instrumental analysis, scanning electron microscopy, optical microscopy, particle size, x‐ray diffraction, swelling power and solubility, paste clarity, pasting properties, thermal properties, and absolute density are used to evaluate the isolated starches. Yield increased from 29.85% (control) to 32.09% (70% amplitude, 15 min). The surface of certain sonicated treated starch becomes damaged, also amorphous region is reduced, but no change in the crystalline pattern of starch is observed, characterized as B type. Except for treated starches at 70% amplitude for 15 min, all others showed no change or slight increase of peak viscosity. Despite the increase in yield, ultrasound caused changes on physical and chemical characteristics, depending on time and amplitude, hence it may be used as alternative technique for physical starch modification, for example, for producing thickeners agent.

Effect of Ultrasound‐Assisted Isolation on Yield and Properties of High‐Amylose Starch from Amylomaize

“…Ultrasound did not cause changes in starch size (p > 0.05), which implied that sonication did not alter the starch average particle size by disrupting protein matrix. Park et al [23] and Bernardo et al [26] had the similar results with this study. It was reported that high levels of amplitude and time affected starch granule size distribution when they are free.…”

“…And the damage on starch granules was aggravated as the amplitude or power of the ultrasound increased. [25,26] Based on the results, it would be inferred that the effect of sonication on starch isolation depended on more than factors of the ultrasound, botanical origin of the starch would be another essential factor.…”

“…There were numerous clearly visible scratches on the granule surface of sonicated pulse starches and the extent of the damage increased with an increase in the amplitude or power of the ultrasound . And for yam starch isolation, ultrasound increased starch damage and yellow color depending on time and amplitude, which in turn reduced swelling power and paste viscosity, particularly peak viscosity …”

“…[25] And for yam starch isolation, ultrasound increased starch damage and yellow color depending on time and amplitude, which in turn reduced swelling power and paste viscosity, particularly peak viscosity. [26] So it was found that effects of ultrasound varied with the botanical source of isolated starches. The modification of isolated yam starch might be the result of the less compact matrix and starch granule, which are different from that of cereal starches.…”

Preparation of octenyl succinic anhydride‐modified cassava starch by the ultrasonic‐assisted method and its influence mechanism

“…After ultrasonic treatment for 8 min, some irregular starch molecules in crystalline regions were hydrated and the amplitude of free vibration increased. After a long period of vibration, these molecules rearranged to form a more stable and an ordered crystalline structure (Bernardo, Ascheri, Chávez, & Carvalho, ). Therefore, the crystallinity and the ratio of 1,047 cm −1 /1,022 cm −1 increased, the organization of double‐helix structure became better and T 2,2 disappeared.…”