Yayuan Zhang

The impacts of environmental conditions on pasting and physicochemical properties were investigated using flour samples of the same cassava cultivar grown in seven different locations. Significant location differences in essential component (except for fiber) content of cassava flour were observed. Cassava flour showed obviously separated traits in the principal component analysis (PCA) of near-infrared spectra (NIR) according to geographical origins. The environmental effects were significant in the pasting properties of cassava flours. Sufficient precipitation and suitable low temperature promoted accumulation of starch in cassava, resulting in the high peak viscosity values of cassava flour. Pasting temperatures of cassava flour had a significant direct correlation with growth temperature and were negatively correlated with altitude. Precipitation from August to October showed a stronger direct correlation with trough and final viscosity. The results of this study indicated the possibility of predicting and controlling cassava flour quality and pasting properties according to the environmental conditions.

Resistant starch, a functional food ingredient, can improve the nutritional value of food products. In this study, the in vitro digestibility of starch from banana flour at four ripening stages was evaluated. The result showed that the resistant starch content of banana flour at ripening stage 1 was up to 81%. Furthermore, to explore the effect of resistant starch in the body, the in vivo digestibility of banana flour was investigated. The intake of banana flour at ripening stage 1 resulted in a nearly 70% decrease in the homeostasis model assessment of insulin resistance value, compared to that of the model group. By contrast, the genes related to glucokinase were upregulated by 66%, and the expression level of the insulin receptor gene was increased by more than 1.5 times that of the model group. Thus, natural banana flour has potential for controlling type 2 diabetes mellitus.

The aim of this study was to explore the relationships between cell structure alterations and postharvest berry abscission in ‘Muscat Kyoho’, ‘Kyoho’ and ‘Nanyu’ table grapes stored for 0 d, 3 d or 6 d at room temperature. Microstructure analysis showed that a large number of the stalk-berry junction cells of ‘Muscat Kyoho’ and ‘Kyoho’ were lignified and suberized at 0 d, whereas these events seldom occurred in ‘Nanyu’. Furthermore, the berry brush cells of the three varieties, especially those of ‘Nanyu’, were small and dense. At 3 d, the numbers of lignified and suberized cells of ‘Muscat Kyoho’ and ‘Kyoho’ were reduced, and the cells had degraded, ruptured and disappeared by 6 d. The berry brush cells of ‘Muscat Kyoho’ and ‘Kyoho’ were larger and more loosely arranged than were those of ‘Nanyu’. Ultrastructure analysis showed that the cells increased in size from small to large and became loosely arranged; the smallest changes were observed in ‘Nanyu’. The cells of ‘Muscat Kyoho’ and ‘Kyoho’ were hydrolyzed, liquated and covered by granular substances at 6 d, and these features were especially prominent in ‘Muscat Kyoho’. The detachment force of grapes declined steadily (p<0.05) and was accompanied by an increase in berry abscission. ‘Nanyu’ maintained the highest detachment force and the lowest berry abscission during storage (p<0.05), followed by ‘Kyoho’ and ‘Muscat Kyoho’. The structural alterations were directly related to berry abscission and correlated inversely with detachment force, with the greatest alterations occurring in ‘Muscat Kyoho’, followed by ‘Kyoho’ and then ‘Nanyu’.