In vitro Digestibility of Raw Starches Extracted from five Yam (Dioscorea spp.) Species Grown in Jamaica

Abstract

Starch granules from Round leaf yellow yam, Negro yam, Sweet yam, Bitter yam and Chinese yam grown in Jamaica were isolated and characterized. The amylose content, granular size, crystallinity, and digestibility by α‐amylase were determined. The granules obtained were of three crystalline types. Round leaf yellow yam, Negro yam and Sweet yam were found to be type‐B, while Chinese yam and Bitter yam were type‐C and type‐A, respectively. Round leaf yellow yam had the highest amylose content (26.5%) while Chinese yam had the lowest (11.1%). The granule size varied between 1–3 μm for Chinese yam and 16–42 μm for Round leaf yellow yam. Significant variations in digestibility of the granules were observed. Raw starches from Chinese yam and Bitter yam were the most susceptible to α‐amylase digestion (porcine pancreatic α‐amylase, pH 5.5, 0.02% CaCl2, 40°C, 24 h) with 21.27 ± 0.01% and 18.11 ± 0.02% degradation, respectively, while Round leaf yellow yam, Negro yam and Sweet yam starches were the least susceptible, with 13.74 ± 0.03%, 14.98 ± 0.08%, and 15.32 ± 0.04% enzymatic degradation, respectively.

Physicochemical properties of five cocoyam (Colocasia esculenta and Xanthosoma sagittifolium) starches

“…The variation in levels of nutrients and anti-nutritional factors observed among the varieties and field preparations may offer some meaningful information for taro cultivation and for further processing operations (Huang, Chen, & Wang, 2007). According to Riley et al (2004) the difference in amylose content observed may be attributed to genetic variations among the cultivars. In fact, it has been postulated that the amylose content of starches is affected by the expression of the amylose extender gene (Noda, Takahata, & Nagata, 1992).…”

Physicochemical properties and starch digestibility of Scirpus grossus flour and starch

“…Physicochemical properties, such as percent light transmittance, amylose content, swelling power and water-binding capacity were significantly correlated with the average granule size of the starches separated from different plant sources (Singh et al, 2003 andZhou et al, 1998). The smaller granule sizes have been found to improve the digestibility because smaller granules have a greater surface area and are more rapidly digested by enzymes (Cone and Wolters, 1990, Franco et al, 1992and Riley, 2004. Apart from morphological properties, molecular structure of starches as obtained by size exclusion chromatography and/or fluorophore-assisted capillary electrophoresis is suggested.…”

Relationship between the physicochemical properties of starches and the glycemic indices of some Jamaican yams (Dioscoreaspp.)

“…Starches extracted from Jamaican yams have shown significant variations in their physical and chemical properties [3]. These differences in the starches physicochemical properties often tend to illicit variations in functional characteristics such as digestibility and crystallinity [3]. The variations in starch properties and botanical origin have also been shown to impact on the metabolic effects and the susceptibility of starch to a-amylase digestion [4].…”

“…Starches extracted from Jamaican yams have shown significant variations in their physical and chemical properties [3]. These differences in the starches physicochemical properties often tend to illicit variations in functional characteristics such as digestibility and crystallinity [3].…”

“…Significant differences in physicochemical properties of yam starches [3] as well as in the GIs of different West Indian foods [10] have been reported. However, the relationship between the starch properties and GI in the tubers studied remain to be explored.…”