Quercetin and quercetin glycosides are physiologically active flavonol molecules that have been attributed numerous health benefits. Recovery of such molecules from plant matrices depends on a variety of factors including polarity of the extraction solvent. Among the solvents of a wide range of dielectric constants, methanol recovered the most quercetin and its glycosides from dehydrated ‘Idared’ apple peels. When ultrasonication was employed to facilitate the extraction, exposure of 15 min of ultrasound wavelengths of dehydrated apple peel powder in 80% to 100% (v/v) methanol in 1:50 (w:v) solid to solvent ratio provided the optimum extraction conditions for quercetin and its glycosides. Acidification of extraction solvent with 0.1% (v/v) or higher concentrations of HCl led to hydrolysis of naturally occurring quercetin glycosides into the aglycone as an extraction artifact.

The consumption of navy beans (Phaseolus vulgaris L.) is associated with reduced cardiometabolic risk factors such as improved blood glucose control. Navy bean flours retain the nutritional benefits of navy beans, which are high in protein and fiber and low in fat and sugar. However, the particle size of navy bean flours can vary depending on the milling technology used. The purpose of this study was to investigate the carbohydrate digestion rate of navy bean flours with various particle sizes. Five samples each of raw and baked flours with the following volume-weighted mean particle sizes were studied by in vitro digestion using the Englyst method: coarse (1,101.6 µm), regular (630.7 µm), fine (301.7 µm), very fine (144 µm), and superfine (26.8 µm). An increase in the particle size of dry-milled navy bean flours was associated with a reduced in vitro carbohydrate digestion rate that was partially retained after baking and could be explained by the higher resistant starch and insoluble nonstarch polysaccharide contents and lower available carbohydrate content compared with flours with smaller particle sizes. The results of this study provide information that can be used in the development of functional foods for blood glucose control using navy bean flours.

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Background and objectives: Regular intake of pulses has been shown to offer numerous health benefits, including improved glycemic control. The objective of this study was to investigate the in vitro carbohydrate digestion rate of raw, baked, and moist-heat cooked lentil flours of varying particle sizes: coarse (710-1,190 μm), regular (355-710 μm), fine (180-355 μm), very fine (80-180 μm), and superfine (<80 μm) over 180 min using the Englyst method. Findings: There was an effect of particle size (p < .05), time (p < .05), and a particle size-by-time interaction (p < .05) on glucose release in raw, baked, and moist-heat cooked lentils flours digested in vitro over 180 min. The magnitude of glucose release was lower for the coarse compared to finer grinds (p < .05) in raw, baked, and moist-heat cooked samples and could be attributed to the lower starch damage, lower amounts of available carbohydrates, and higher amounts of resistant starch. Conclusions: The larger particle size of lentil flour is associated with reduced glucose release upon simulated gastrointestinal digestion which was partially retained after baking or moist-heat cooking. Significance and novelty: This is the first study demonstrating that lentil flours varying in their average particle sizes have distinct content of resistant and available carbohydrates that may predict their glycemic properties. K E Y W O R D Sglucose, in vitro digestion, lentil, lentil flour, particle size

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