Hypoglycemic Effects of Insoluble Fiber Rich Fraction of Different Cereals and Millets

Abstract

Dietary fibers are important for their hypoglycemic effect, hypolipidemic effect; lowering serum cholesterol hence helps in prevention of atherosclerosis, antitoxic effect and anti-cancerous effect. It also helps in control of gastro intestinal disorders like gall stone, irritable bowel syndrome, constipation, inflammatory bowel disease etc. Beneficial effects of cereal fibers are frequently discussed in the context of whole grain consumption; unrefined whole grains and bran products are highly complex substances containing both soluble and insoluble dietary fiber as well as other biologically active substances e.g. polyphenols, antioxidants, vitamins, trace minerals, phytoestrogens, lipids, proteins, and starch. Research on minor millets and its food value is in its infancy and its potential vastly untapped. So the present study was undertaken to evaluate the in-vitro hypoglycemic effect of insoluble fibers from locally available whole grain of millets and cereals like kodo millet (Paspalum scrobiculatum), Proso millet (Panicum miliaceum), Barnyard millet (Echinochloa frumentaceae), Finger millet (Elusine coracana), wheat (Triticum aestivum) and Great millet (Sorghum vulgare) from tribal belt of Odisha. Proximate analysis of the cereals and millet grains revealed that these grains are rich in crude fiber, total ash and crude protein content. The nutritional composition is better than most of the commonly used grains. In general the crude fiber and ash content of the bran samples were more as compared to the grains. Glucose adsorption capacity (GAC) at 5 Millimole/l concentration of glucose was almost similar in IDF of all the millets and wheat ranging from 0.04 ± 0.01 in case of Barnyard millet IDF to 0.06 ± 0.01 in Sorghum, Ragi and Kodo. Glucose absorption capacity at 5 Millimole/l concentration of glucose was highest in Ragi fibers but at higher concentration of glucose it was highest in wheat fibres. GAC increases with increase in glucose concentration in all the cases studied. In most samples WIS showed maximum GAC. Maximum GAC was found at 50 mM/lit in Ragi (Finger millet) IDF and lowest value was found at 10 mM/lit in jhipiri (Barnyard millet) IDF and wheat AIS. In case of glucose diffusion and GDRI, in all types of fiber, it showed decrease in glucose concentration in the dialysate with addition of fiber than in control (without fiber), indicating that addition of fiber decreased diffusion of glucose through dialysis membrane which simulates the function of membrane of small intestine. The glucose concentration in the dialysate though increases with increase in time but remains lower to that of glucose value in control. When GDRI values were compared it showed lowest value in case of IDF than AIS and WIS in all the six samples. Effect of insoluble fibers on alpha-amylase activity indicate that glucose production rate is highest in kodo (kodo millet) AIS but lowest in sorghum (Great millet) IDF. When residual amylase activity was compared it showed highest values in Ragi (Finger millet) AIS and lowest values in gunji (Proso millet) IDF.