"Studies On The Preparation Of Fibersol-2 And Its Physiological Functions"

It is often stated that the polysaccharide components of cereals might lead to a general reduction in the bioavailability of mineral nutrients by the formation of non-absorbable complexes in the intestinal lumen. One must reject the above hypothesis, as now the presence of the soluble dietary fibers is known. Starch hydrolysates containing the indigestible components are termed resistant maltodextrins. One of those resistant maltodextrins has physiological attributes resembling those of dietary fiber;named Fibersol-2 with an average molecular weight of 2000Da. Fibersol-2 reaches the large intestine undigested where it is partly fermented by bacteria, producing short-chain fatty acids (SCFA) with the remaining being excreted in the feces.In this study, commercial cornstarch (250g) was pretreated with 1% hydrochloric acid. The pyrodextrin obtained after pretreatment, was subjected to enzymatic hydrolysis by using 0.1% α-amylase in order to prepare fibersol-2. Then the product obtained was spray-dried after purification (decolorization and desalting). After modification of the preparation condition, by HPLC determination, the hydrolysate showed a molecular weight of 2204Da of fibersol-2 content, which is very near to that of the standard.The main idea of desalting fibersol-2 is to remove free glucose liberated during enzymatic hydrolysis from a high-molecular-weight fraction, through a column of strongly acid cation exchange resin for chromatography. This study confirm that, the use of a column of strongly acid cation resin for chromatography can separate efficiently the high-molecular-weight dextrin from glucose liberated after enzymatic hydrolysis of the pretreated pyrodextrin. Unfortunately, this cation- exchange chromatography method is practically not suitable for large-scale production of fibersol-2.This study made use of applying brewing yeast Saccharomyces cerevisiae for desalting fibersol-2. The use of Saccharomyces cerevisiae was also a good tool for glucose removal from the prepared hydrolysate pyrodextrin or fibersol-2 with the free sugars. The rates of glucose removal are affected by yeast concentration, fermentation time and temperature. The results of these studies show that it is not necessary to dilute total soluble sugars content from the hydrolysate pyrodextrin for fermentation. The application of Saccharomyces cerevisiae for desalting fibersol-2 was optimally realized with respect to the following conditions: yeast concentration (0.5%), temperature (20℃) and time (24 hours) without soluble sugars dilution. The rate of glucose removal under the above conditions was 98.27%, which is considered acceptable and economically less costly,compared to others removal rates. The remaining glucose in the fibersol-2 is very little that it qualifies to be termed as negligible.In order for fibersol-2 to be accepted as a dietary fiber, a low-molecular weight soluble dietary fiber component in fibersol-2 was precipitated in 78% ethanol. Low-molecular weight soluble dietary fiber was determined from the ratio of peak area of a part of fibersol-2 in HPLC chromatograms of the above filtrates. Finally, total dietary fiber was calculated by summing the value from the AOAC method and that from HPLC procedure. The total dietary fiber (TDF) content was 94%.The usual method to remove the undesirable color of fibersol-2 is by use of activated charcoal, which purifies the product to a white color. In this study, the decolorization using activated charcoal was replaced by a calcium binding process. Fibersol-2 does not affect calcium absorption in the human digestive tract. Thus, the purpose for fortifying calcium to fibersol-2 was developed, in order to enable self-monitoring of calcium consumption, since any calcium associated to fibersol-2 will be released after partial fermentation of fibersol-2 in the large intestines. The application of calcium binding to the preparation of fibersol-2 gave an acceptable white bright color and a good taste to the product as it was demonstrated by the sensory evaluation, result.The application of activated charcoal for decolorization can be well replaced by the calcium binding process, since the latter will also remove the unpleasant color of fibersol-2 and give a bright white color to the product. In addition, the product fibersol-2 after calcium binding has high nutritional value, compared to the product fibersol-2 obtained by using activated charcoal. The amount and percentage of fortified calcium to fibersol-2 were 4.9373 mg/g and 53.24% respectively. The recovery of the Laboratory prepared fibersol-2 and the Laboratory prepared calcium fortified fibersol-2 was also 67.18% and 66.84% respectively.Animal test was adapted to test environments to evaluate the bioavailability of calcium and its effect on blood glucose levels. The results indicated that laboratory prepared fibersol-2 does not inhibit calcium absorption, and laboratory prepared calcium fortified fibersol-2 can slightly improve calcium absorption. In addition, the calcium retention rates after feeding four groups of mice (Group 1 - Blank, Group 2 - Laboratory prepared fibersol-2, Group 3 - Laboratory prepared calcium fortified fibersol-2 and Group 4 -CaCl2 solution) were 0.75%, 16.27%, 77.95% and 96.69% respectively. Calcium retention rate of the laboratory prepared calcium fortified fibersol-2 (77.95%) is higher;Southern Yangtze University. Ph.D. Dissertation_________________________Abstractwhich rate comes after the rate of CaCk solution. But the consumption of CaC^with the feed can not provide healthy mice compared to other groups.The statistical analysis using SPSS software shows insignificant difference of the blood glucose levels of the two products as analyzed by Duncan's test. The blood glucose levels of the two products were between the normal ranges (3.85-6.2mmol/L), which demonstrates absence of significant increase in blood glucose level. The insulin secretion levels of mice fed with the laboratory prepared fibersol-2 and laboratory prepared calcium fortified fibersol-2 were also between the normal ranges (1.9-23mmol/L). These results indicated that the laboratory prepared fibersol-2, as well as the laboratory prepared calcium fortified fibersol-2 improved glucose tolerance and no delay of calcium absorption occured in the digestive tract.The effect of laboratory prepared fibersol-2 and those of laboratory prepared calcium fortified fibersol-2 on blood glucose levels indicated that, there is no inhibition of physical absorption of calcium in the digestive tract, and no gel formation at all. The effect of fibersol-2 on blood glucose levels differs from that of viscous soluble dietary fibers such as pectin or guar gum, the latter compounds inhibiting physical absorption of nutrients in the digestive tract by the formation of a gel.The mean sensory scores show statistically significant difference between the cakes made with laboratory prepared calcium fortified fibersol-2, without fortification and the control cakes, as well as for color and for taste analysis. The results indicated that, color of the cakes made with the laboratory prepared calcium fortified fibersol-2 is more attractive than the color of the cakes made with the laboratory prepared fibersol-2 (without fortification), none the less the latter was still more attractive than the control cakes. The mean sensory scores of cakes indicated also the same tendency for their taste. However, the overall acceptability of the prepared cakes shows statistically insignificant difference between the cakes made with laboratory prepared calcium fortified fibersol-2 and the laboratory prepared fibersol-2 (without fortification). Also, the same results show statistically insignificant difference between the cakes made with laboratory fibersol-2 and the control cakes;but statistically significant difference between the cakes made with the laboratory prepared calcium fortified fibersol-2 and the control cakes, which results indicated that both cakes made with the laboratory prepared calcium fortified fibersol-2 and the laboratory prepared fibersol-2 have an acceptable color and taste.Southern Yangtze University. Ph.D. Dissertation_________________________AbstractThis study indicated that, application of the laboratory prepared calcium fortified fibersol-2 and the laboratory prepared fibersol-2 in cake making shows acceptable cakes in color and taste after sensory evaluation.