Jiali Yang,Xia Jiang,Rong Zhang,Qinxiang Luo,Bin Wang,Xuewei Shi,Zhangying Wang
The quality of table-stock sweetpotatoes is significantly influenced by carbohydrates. The study investigated the changes of dry matter, starch, amylose, soluble sugar and 22 sugars in six purple-fleshed sweetpotatoes (PFSPs) with different anthocyanin contents harvested at 75, 105, 135, 165 days after transplanting, and revealed the accumulation pattern of carbohydrates in PFSPs. The dry matter accumulated constantly. The starch content decreased at 165d in GZ1, GZ9, GZ10 and G95–1, while GZ2 and G20 continued to accumulate with more starchiness taste. The accumulation of soluble sugars was primarily observed in 75–135 days, with sucrose, glucose, and D-fructose representing the predominant sugars. The proportion of sucrose varying from 41.75 % to 87.07 %, but decreased at 165d accompanying with the increasing of glucose and fructose. GZ1 exhibited the most favorable taste profile with higher sweetness and GZ10 accumulated sugar rapidly at 165d, making it the most suitable for harvesting later. While GZ2, GZ9, G20 and G95–1 accumulated carbohydrates rapidly in 75–135 days, which can be harvested appropriately early. This study can provide a theoretical basis for the selection and breeding for better quality of PFSPs.
This study aimed to evaluate and understand the water–ethanol system effect on the stability of purple-fleshed sweet potato anthocyanins (PSPa). The stability of the PSPa in the model ethanol–water solutions (0–80%, vol/vol, pH 3.5) during storage (60 hr) at room temperature was monitored by UV-vis. The frontier molecular orbital theory was used to interpret the hydration reaction rate of the PSPa in both ethanol–water and aqueous solutions. In all of the model ethanol–water solutions, the degradation of the PSPa followed first-order kinetics during storage, and the degradation rates increased with increased ethanol concentration. Theory calculation results showed that an increase in ethanol concentration decreased the LUMO energy of anthocyanins, and accelerated nucleophilic attack from water, thus, resulting in lower stability. These findings could provide valuable evidence of the solvent effect on the stability of anthocyanins. Practical applications Fruit wines that contain anthocyanins are among the common alcoholic beverages. The stability of the anthocyanins is responsible for wine quality and may also affect the nutritional properties. Thus, investigating the effect of ethanol on the stability of anthocyanins is particularly valuable. The results of this research have important implications for the models developed so far to explain the degradation mechanism of anthocyanins in different media. In this context, examining the effect of different media on the degradation of anthocyanins would be useful to provide improved anthocyanin ability in the food and beverage industry.
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