Xinhui Mao

Effects of drying processes on starch-related physicochemical properties, bioactive components and antioxidant properties of yam flours

The effects of five different drying processes, air drying (AD), sulphur fumigation drying (SFD), hot air drying (HAD), freeze drying (FD) and microwave drying (MWD) for yams in terms of starch-related properties and antioxidant activity were studied. From the results of scanning electron microscopy (SEM), polarized optical microscopy (POM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR), the MWD sample was found to contain gelatinized starch granules. The FD yam had more slow digestible (SDS) and resistant starches (RS) compared with those processed with other modern drying methods. The bioactive components and the reducing power of the dried yams, were lower than those of fresh yam. When five dried samples were compared by principal component analysis, the HAD and SFD samples were observed to have the highest comprehensive principal component values. Based on our results, HAD would be a better method for yam drying than the more traditional SFD.

Physicochemical characterisation, digestibility and anticonstipation activity of some high‐resistant untraditional starches from zingiberaceae plants

To find new starch sources with particular characteristics, five untraditional starches from zingiberaceae plants were studied about their physicochemical properties, digestibility and anticonstipation activity and compared with starches from traditional sources (potato and corn). All the five starches presented the shape of triangular, with visible thin sheet, which were significantly different from conventional sources. The crystal type of these five starches was B-type pattern. Swelling power at 75 °C was negatively correlated with crystallinity. There was no significant difference in amylose content between starches from rhizome and tuber of Curcuma phaeocaulis Val., while they displayed significant variability in RS content. Starches from rhizome of Curcuma kwangsiensis, Curcuma wenyujin, Curcuma phaeocaulis Val. and Curcuma longa L. possessed much higher resistant starch content (range from 87.06% to 95.40%) and could better prevent constipation than potato and corn starches, which made them potential for managing diabetes and improving defecation conditions.

Effect of Natural β-Glucosidase Inhibitors in Reducing Toxicity of Amygdalin in Persicae Semen: Screening of Herbs for Oral Form Safety of Amygdalin

Amygdalin can be decomposed into hydrocyanic acid, which is the primary source of Persicae Semen toxicity, by gut flora. Here, the inhibitory activity of β‐glucosidase for test herb extracts was first determined and compared. In turn, optimization of the ratio of substrate and inhibitor in vitro and LD50 values of extracts, serum and liver contents of amygdalin in vivo was measured. Lycii Cortex was found to be the best inhibitory activity for β‐glucosidase. The ratio of amygdalin‐to‐Lycii Cortex extract of 7.19:8.18 (mmol L−1/mg mL−1) can be relatively suitable for inhibiting β‐glucosidase activity in test in vitro reaction system. After mixed with Lycii Cortex extract, the toxicity of Persicae Semen ethanol extract in mice is significantly reduced and more amygdalin can be absorbed into the bloodstream. The study provides useful information for reducing toxicity of Persicae Semen and suggests how to better use these natural β‐glucosidase inhibitors in the utilization of glycosides and aglycones. Copyright