Influences of Waxy Rice Protein Network on Physical Properties of Waxy Rice Flour Composites

ABSTRACT The roles of waxy rice protein network as a binder on thermal, pasting and microstructural characteristics of waxy rice flour (WF)-mungbean starch (MB) were demonstrated. The presence of WF, even at one-tenth of the total solid, lowered both enthalpy of gelatinisation and enthalpy for retrogradation reversal of the WF-MB flour composite compared to those of MB (P<0.05). The timedependent shear-thinning characteristics at 95°C of WF, WF-MB and MB indicated that the composites with high ratio of WF to MB resisted shear the most (P<0.05) during Rapid Visco Analysis (RVA). Confocal Laser Scanning Microscopy (CLSM) showed the swollen MB granules were bound by the protein network of WF after heat treatment. The resistance to shear during pasting of WF-MB composites, compared to those of WF or MB alone, were likely to be due to the binding of the swollen MB granules via interfacial interactions between WF protein network and the protein at the envelope of MB granules. This study highlighted the influences of microstructural alteration, through network formation of proteins, on the bulk pasting profiles and thermal properties of both starch and flour

Profiling Anthocyanins in Thai Purple Yams (Dioscorea alata L.)

Two accessions of Thai purple yam (Dioscorea alata) were investigated for their chemical constituents during tuber development when the vines were 3 to 8 months old. Yam tubers contained total phenolic compounds ranging between 100 and 385 mg gallic acid equivalent (GAE), flavonoids 60–160 mg catechin equivalent (CE), monomeric anthocyanin of 10–90 mg cyanidin-3-glucoside equivalent (CGE), 70 g starch, and 25–30 g amylose in 100 g yam tuber on a dried weight basis, depending on the accession and age of yam vine. LCMS-IT-TOF mass spectrometry revealed that anthocyanins in both accessions from 8-month-old vines had cyanidin or peonidin nucleus. Their glycosides were nonacylated, monoacylated, or diacylated with sinapic or ferulic acid. The major yam anthocyanins found in both accessions were alatanin C (cyanidin 3-(6-sinapoyl gentiobioside). This study revealed the insights on chemical components during tuber development and characteristics of alatanins for future selection and cultivation of purple yam tubers

Water Extract of Mungbean (Vigna radiata L.) Inhibits Protein Tyrosine Phosphatase-1B in Insulin-Resistant HepG2 Cells

The present study aimed to investigate the effects of mungbean water extract (MWE) on insulin downstream signaling in insulin-resistant HepG2 cells. Whole seed mungbean was extracted using boiling water, mimicking a traditional cooking method. Vitexin and isovitexin were identified in MWE. The results showed that MWE inhibited protein tyrosine phosphatase (PTP)-1B (IC50 = 10 μg/mL), a negative regulator of insulin signaling. MWE enhanced cellular glucose uptake and altered expression of genes involved in glucose metabolism, including forkhead box O1 (FOXO1), phosphoenolpyruvate carboxykinase (PEPCK), and glycogen synthase kinase (GSK)-3β in the insulin-resistant HepG2 cells. In addition, MWE inhibited both α-amylase (IC50 = 36.65 mg/mL) and α-glucosidase (IC50 = 3.07 mg/mL). MWE also inhibited the formation of advanced glycation end products (AGEs) (IC50 = 2.28 mg/mL). This is the first study to show that mungbean water extract increased cellular glucose uptake and improved insulin sensitivity of insulin-resistant HepG2 cells through PTP-1B inhibition and modulating the expression of genes related to glucose metabolism. This suggests that mungbean water extract has the potential to be a functional ingredient for diabetes

Water Extract of Mungbean (<i>Vigna radiata</i> L.) Inhibits Protein Tyrosine Phosphatase-1B in Insulin-Resistant HepG2 Cells

The present study aimed to investigate the effects of mungbean water extract (MWE) on insulin downstream signaling in insulin-resistant HepG2 cells. Whole seed mungbean was extracted using boiling water, mimicking a traditional cooking method. Vitexin and isovitexin were identified in MWE. The results showed that MWE inhibited protein tyrosine phosphatase (PTP)-1B (IC50 = 10 μg/mL), a negative regulator of insulin signaling. MWE enhanced cellular glucose uptake and altered expression of genes involved in glucose metabolism, including forkhead box O1 (FOXO1), phosphoenolpyruvate carboxykinase (PEPCK), and glycogen synthase kinase (GSK)-3β in the insulin-resistant HepG2 cells. In addition, MWE inhibited both α-amylase (IC50 = 36.65 mg/mL) and α-glucosidase (IC50 = 3.07 mg/mL). MWE also inhibited the formation of advanced glycation end products (AGEs) (IC50 = 2.28 mg/mL). This is the first study to show that mungbean water extract increased cellular glucose uptake and improved insulin sensitivity of insulin-resistant HepG2 cells through PTP-1B inhibition and modulating the expression of genes related to glucose metabolism. This suggests that mungbean water extract has the potential to be a functional ingredient for diabetes