Comparison of Structural and Functional Properties of Starches from the Rhizome and Bulbil of Chinese Yam (Dioscorea opposita Thunb.)

Abstract

Chinese yam is an important edible starch plant and widely cultivated in China. Its rhizome and bulbil are starch storage tissues below and above ground, respectively. In this paper, starches were isolated from the rhizome and bulbil of Chinese yam, and their structural and functional properties were compared. Both starches had an oval shape with an eccentric hilum and a CA-type crystalline structure. Their short-range ordered structure and lamellar structure had no significant difference. However, the rhizome starch had a significantly bigger granule size and lower amylose content than the bulbil starch. The swelling power and water solubility were significantly lower in the rhizome starch than in the bulbil starch. The onset and peak gelatinization temperatures were significantly higher in the rhizome starch than in the bulbil starch. The rhizome starch had a significantly higher breakdown viscosity and a lower setback viscosity than the bulbil starch. The thermal stability was lower in the rhizome starch than in the bulbil starch. The rhizome starch had a significantly lower resistance to hydrolysis and in vitro digestion than the bulbil starch. The above results provide important information for the utilization of rhizome and bulbil starches of Chinese yam.

An underutilized orphan tuber crop—Chinese yam : a review

“…Other patents in the area of 'medical and veterinary science' indicate the potential utilization of Chinese yam starch as a functional food, including a drink ingredient that is purported to activate stem cell growth (Weng and Wu 2016). Approximately 85% of the starch produced by Chinese yam plants is stored in the underground tubers for vegetative re-sprouting (Zhang et al 2014(Zhang et al , 2018, representing ~ 67% of the total dry weight of the tuber (Zhou et al 2012;Zhang et al 2018). Most of the rest is stored in the bulbils (Zhou et al 2012;Zhang et al 2018).…”

“…Approximately 85% of the starch produced by Chinese yam plants is stored in the underground tubers for vegetative re-sprouting (Zhang et al 2014 , 2018 ), representing ~ 67% of the total dry weight of the tuber (Zhou et al 2012 ; Zhang et al 2018 ). Most of the rest is stored in the bulbils (Zhou et al 2012 ; Zhang et al 2018 ).…”

“…Approximately 85% of the starch produced by Chinese yam plants is stored in the underground tubers for vegetative re-sprouting (Zhang et al 2014 , 2018 ), representing ~ 67% of the total dry weight of the tuber (Zhou et al 2012 ; Zhang et al 2018 ). Most of the rest is stored in the bulbils (Zhou et al 2012 ; Zhang et al 2018 ). The bulbil starch has greater swelling power, solubility in water and viscosity than tuber starch, and also greater thermostability and resistance to hydrolysis, reflecting the higher amylose content of 38% in bulbils compared to 35% in tubers (Zhang et al 2018 ; Zhou et al 2012 ).…”

Characterization and Comparison of Alkali Extracted Starches from Selected Cereals and Tubers

“…These good organoleptic properties make it an interesting resource for manifold applications, not only in human food and animal feed but also as feedstock for nonfood industrial applications such as pulp and paper, adhesives and bioethanol [3]. Starch is a valuable ingredient in the food industry, it serves not only as a nutrient source for food but also as a thickener, a binding agent, a texturizer, a filler and a film-forming agent in the food industry [4,5,6].…”

“…Being a tropical country, Sri Lanka has underutilized cereals and yams with a higher content of starches and may be possessing good physicchemical properties for industrial applications. Further, extraction of starches from these underutilized cereals may improve the value-adding options for underutilized crops and enhance our understanding and knowledge about physicochemical and functional properties of new starchy materials as well as their ability to replace conventional starch in the food industry [5]. Thus the application of non-conventional starch sources of cereals, roots and tubers in the food industry can be broadened which in turn may reduce the dependency on corn, wheat and cassava as the main sources of starch.…”