Corn Resistant Starch Research Articles

Effect of high-pressure treatment on the structural and rheological properties of resistant corn starch/locust bean gum mixtures

In this study, effects of a 30min high pressure (HP) treatment (200–600MPa) at room temperature on the rheological, thermal and morphological properties of resistant corn starch (RS) (5% w/w) and locust bean gum (LBG) (0.25, 0.50 and 1.0% w/v) dispersions were evaluated. Results showed that the storage modulus (G′), loss modulus (G′′), and apparent viscosity values of starch/gum (RS/LBG) mixtures were enhanced with an increase pressure level, and demonstrated a bi-phasic behavior. HP treated RS/LBG samples were predominantly either solid like (G′>G′′) or viscous (G′′>G′), depending on the pressure level and LBG concentrations. Differential scanning calorimetry (DSC) analysis of the pressurized mixtures showed a major effect on gelatinization temperatures (To, Tp,), and it was observed that RS/LBG mixtures gelatinized completely at ≥400MPa with a 30min holding time. Confocal laser scanning microscopy (CLSM) images confirmed that at 600MPa, RS/LBG mixtures retained granular structures and their complete disintegration was not observed even at the endpoint of the gelatinization.

Prebiotics and β‐Glucan Affect Jejunal and Serum Alkaline Phosphatase Affinity in Weanling Pigs

Biological mechanisms of dietary supplementation of prebiotics and β‐glucan in modulation of health status need further clarification. Given the recognized role of alkaline phosphatases (AP) in detoxification of endotoxin lipopolysaccharides (LPS), we hypothesized that dietary supplementation of three prebiotics and β‐glucan in modulation of health status was mediated through affecting alkaline phosphatase functionality such as maximal enzyme activity (Vmax) and enzyme affinity (Km). This study was conducted to determine effects of dietary supplementation of three prebiotics and β‐glucan at 0.75% instead of feed antibiotics on growth performance, blood urea concentration, fecal scores, jejunal and serum AP kinetics and large intestinal fermentation in weanling piglets fed corn and soybean meal (SBM)‐based diets. Six experimental diets were formulated with corn, SBM and fishmeal as the bulk ingredients. This includes Diet 1, a negative control (NC) of the basal diet with no supplemental feed antibiotics and no tested supplements; Diet 2, a positive control (PC) of the basal diet with supplemental feed antibiotics but no other tested supplements; Diet 3, a retrograded resistant corn starch supplementation of the basal diet with no supplemental feed antibiotics; Diet 4, an oat β‐glucan supplementation of the basal diet with no supplemental feed antibiotics; Diet 5, a Fibersol‐2 supplementation of the basal diet with no supplemental feed antibiotics; and Diet 6, an inulin supplementation of the basal diet with no supplemental feed antibiotics. A total of 216 piglets, 21 d old, with an initial body weight of 7.0 kg, were fed 1 of the 6 diets for 21 d in three study blocks according to a completely randomized block design. Dietary supplementation of the three prebiotics and β‐glucan did not significantly affect growth performance and main intestinal fermentation endpoints. Dietary supplementation of β‐glucan in Diet 4 increased (P<0.05) the wk 1–3 overall fecal score compared with the NC diet. Fibersol‐2 in Diet 5 and inulin in Diet 6 reduced (P<0.05) the Vmax of the proximal jejunal AP compared with the NC diet. The Vmax of serum AP was different (P<0.05) between the β‐glucan Diet 4 and the PC diet. Dietary supplementation of Fibersol‐2 in Diet 5 and β‐glucan in Diet 4 increased the AP affinity by about 1 fold compared with the NC diet. Serum AP affinity Km values were at least 10‐fold higher than the Km values of the jejunal AP, suggesting that the proximal jejunal AP is potentially much more efficient than the serum AP in detoxification of endotoxin LPS. Dietary supplementation of the three prebiotics and oat β‐glucan at 0.75% had little effects on growth performance but might affect the gut and whole body health status via influencing the AP detoxification kinetics in the weanling pig.Support or Funding InformationSupported by the NSERC Discovery and the OMAFRA‐University Partnership Programs.

Effects of phosphorylated cross-linked resistant corn starch on the intestinal microflora and short chain fatty acid formation during in vitro human fecal batch culture

Changes in the intestinal microflora and formation of short chain fatty acids (SCFAs) were studied in an in vitro human fecal batch culture in a medium containing 10 mg/mL of phosphorylated cross-linked resistant corn starch (RS4 type) as the sole carbon source. Viable counts of total anaerobic bacteria and bifidobacteria were higher for RS4 than for corn starch, RS2 (Novelose 240), and cellulose. However, viable counts of lactobacilli were decreased for RS4. The total short chain fatty acids (SCFAs) amount was also increased for RS4, corn starch, and RS2, but not for cellulose. The molar ratios of acetic:propionic:butyric acid were 39:20:15 after 36 h of culture in RS4 corn starch. RS4 corn starch promoted the growth of total anaerobic bacteria and bifidobacteria together with SCFAs formations in an in vitro human fecal batch culture.

RS4 형태의 옥수수 저항전분이 첨가된 쿠키의 품질 특성

Effects of RS4 type resistant corn starch on the quality characteristics of cookies were investigated by physicochemical, instrumental and sensory evaluation. The resistant starch was made by cross-linking of corn starch as following; corn starch slurry was annealed at pH 2.0 and for 2 h followed by the cross-linking reaction. The cross-linking reaction was performed at for 12 h in the presence of 1.2%/st.ds NaOH, 10%/st.ds sodium sulfate and 10%/st.ds of sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) mixture. Dietary fiber content of the resistant starch was estimated to be 73.8% by the AOAC method. For quality characteristics, dough pH decreased with the increase of the resistant starch content and spread factor decreased a little at 20% of the resistant starch. The moisture content and L value of cookies increased with the increase of the resistant starch content. However, the hardness and fracturability decreased with the increase of the resistant starch content. In the sensory evaluation, no significant differences were observed between the two cookies with or without the resistant starch. The results of this study suggest that the RS4 type resistant corn starch can be a good ingredient to increase dietary fiber content in cookies without changes of their qualities.

Consumption of guar gum and retrograded high-amylose corn resistant starch increases IL-10 abundance without affecting pro-inflammatory cytokines in the colon of pigs fed a high-fat diet1

Increases in dietary intake of viscous and nonviscous soluble fiber are reported to improve bowel health. However, related biological mechanisms are not very clear. This study was conducted to examine if colonic inflammation would occur in a typical Western diet model and determine if consumption of soluble fiber components would attenuate potential detrimental effects by differentially affecting colonic abundances of anti-inflammatory cytokine IL-10 and 2 pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and IL-6 in pigs fed a high-fat basal diet supplemented, respectively, with 15% viscous soluble fiber guar gum (GG) and 15% nonviscous soluble fiber, that is, retrograded high-amylose corn (Zea mays) resistant starch (RS). A total of 24 Yorkshire growing barrows were assigned into a standard corn and soybean (Glycine max) meal (SBM)-based grower diet as a positive control (PC), an animal protein-based high-fat basal diet as the negative control (NC), and 2 NC basal diets supplemented with 15% GG and 15% RS, respectively, according to a completely randomized block design for 4 wk. Abundance of these cytokines in homogenized and extracted colonic tissue supernatant samples was measured by ELISA. Although colonic IL-10 abundance was lower (P < 0.05) in the corn and SBM-based PC group than that in the high-fat basal NC group, there were no differences (P > 0.05) in colonic abundances of TNF-α and IL-6 between NC and PC groups and among all of the treatment groups. Compared with the NC group, consumption of GG and RS at 15% increased (P < 0.05) colonic IL-10 abundance. Moreover, there was no difference (P > 0.05) in colonic IL-10 abundance between the 15% GG and the 15% RS groups. Thus, consumption of a typical high-fat Western diet did not induce colonic inflammation. Diets supplemented with 15% GG or 15% RS may protect the colon from developing inflammation by enhancing IL-10 abundance.

Preparation Technology of Corn Resistant Starch by Autoclaving Method

Normal corn starch was used as raw material in this research and was treated by autoclaving method to produce corn resistant starch (CRS). This research was focused on techniques of preparing CRS through autoclaving method and effects of autoclaving method parameters on yields of CRS from corn starch. The optimum conditions were investigated with carrying out an L9(34) orthogonal experiment. The yield of CRS was 8.05 % under combination of optimum parameters obtained from L9(34) orthogonal experiment. The optimum parameters were concentration of NCS solution 25 %, pH6.5, autoclaving temperature 125 °C, autoclaving time 35 min.

Resistant Starches (RS2 and RS3) have Variable Effects on Bone Mineral Status in Rats

Nondigestible oligosaccharides may increase mineral absorption by changing the intestinal environment. The effect of feeding a diet containing 5% resistant starch, RS2 (uncooked native) or RS3, (cooked and retrograded) on cal- cium absorption and bone mineral status was studied in growing male rats for 4 weeks. Almost 100g more feed was con- sumed with resistant starch compared to control in four weeks. Mineral status improved as determined by femur concen- tration, but not through absorption. Mineral content of femurs increased 12, 10 and 9% for Ca, Mg and Zn respectively, while Fe decreased 23% after feeding RS3, but not RS2, compared with the control group. There was no increase in the percent retention for any of the tested minerals. 45 Ca absorption capacity was not affected by either resistant starch. We conclude that resistant starches improve mineral status possibly through increased food consumption, but not through in- creased absorption efficiency. potato and high amylose starch, were compared at the same level and fed to rats for 7 days (12), no differences were found in calcium and magnesium absorption. Cecal concen- trations of calcium, potassium, and phosphate, but not of magnesium, were significantly increased in rats fed either 25% or 50% amylose-rich starch, 10% lactulose or 10% pec- tin compared to the control (13). The cecal pool of all these minerals was increased in a dose-dependent manner with the 25% and 50% amylose. All of the studies cited above used high levels of resistant starch (15 to 50%) and some (9,10) used higher levels of dietary calcium (up to 0.75%). The calcium requirement for rats is 0.5%. It is likely that any effect of calcium-absorption enhancers would be dampened above this level. The present study was designed to investigate the effect of two resistant starches, high amylose resistant cornstarch containing 60% resistant starch (RS2) and a high amylomaize retrograded resistant cornstarch containing 55% resistant starch (RS3), at 5% by weight on calcium absorption, mineral balance and bone mineral concentration in rats fed a 0.5% calcium diet.

The impact of resistant starch on characteristics of gluten-free dough and bread

The study focused on partial replacement in gluten-free breads of corn starch with tapioca and corn resistant starch preparations. The use of resistant starch resulted in the increase of storage and loss moduli of the dough, and the lowering of loss tangent, which indicates its more elastic character. The incorporation of resistant starch reduced creep and recovery compliance and elevated zero shear viscosity. Modified doughs displayed higher starch gelatinization temperatures and lower viscosities that were proportional to the share of RS. It was found that the loaves baked with the share of resistant starch had less hard crumb than bread without RS addition. The crumb hardness diminished with the increasing amount of applied RS preparation. The addition of resistant starch raised total dietary fibre, by up to 89%, as compared to control (bread without RS addition). The most pronounced change was observed for insoluble dietary fibre (increase 137%), while only slight increase was found for its soluble fraction (18%).

Nutrient utilisation and intestinal fermentation are differentially affected by the consumption of resistant starch varieties and conventional fibres in pigs

This study examined the influence of different resistant starch (RS) varieties and conventional fibres on the efficiency of nutrient utilisation and intestinal fermentation in pigs. Thirty-six pigs (30 kg) were fed poultry meal-based diets supplemented with 10 % granular resistant corn starch (GCS), granular resistant potato starch (GPS), retrograded resistant corn starch (RCS), guar gum (GG) or cellulose for 36 d according to a completely randomised block design. Distal ileal and total tract recoveries were similar (P>0.05) among the RS varieties. Distal ileal starch recovery was higher (P < 0.05) in pigs consuming the RS diets (27-42 %) as compared with the control group (0.64 %). Consumption of GCS reduced (P < 0.05) apparent total tract digestibility and whole-body retention of crude protein in comparison with the control group. Consumption of GPS reduced (P < 0.05) total tract Ca digestibility and whole-body retention of Ca and P compared with the control group. However, consumption of RCS increased (P < 0.05) total tract Ca digestibility compared with the control group. Caecal butyrate concentration was increased (P < 0.05) following consumption of RCS and GG in comparison with the control group. Consumption of all the RS varieties reduced (P < 0.05) caecal indole concentrations compared with the control. Caecal butyrate concentrations were positively correlated (P < 0.05; r 0.63-0.83) with thermal properties among the RS varieties. We conclude that nutrient utilisation and intestinal fermentation are differentially affected by the consumption of different RS varieties and types of fibres. Thermal properties associated with different RS varieties may be useful markers for developing RS varieties with specific functionality.

Thermal‐physical properties are associated with intestinal nutrient utilization efficiency and fermentation in resistant starch varieties in growing boars fed high‐fat based diets

The relationship between the thermal-physical properties of resistant starch and the efficiency of nutrient utilization and intestinal fermentation was examined in pigs fed resistant corn starch, granular resistant potato starch or retrograded resistant corn starch for 30 d according to a completely randomized block design. Nutrient utilization and cecal short-chain fatty acid concentrations were measured with mass balance and gas chromatography-mass spectrometry, respectively. Thermal physical analyses of the selected starches, including onset and peak temperatures and enthalpy changes, were measured with differential scanning calorimetry. Apparent crude protein digestibility values associated with the RS varieties were negatively correlated (P=0.05; r= −0.45) with enthalpy change while Ca and P digestibility values were positively correlated (P<0.05; r=0.44–0.66) with onset and peak temperatures. Cecal butyrate concentrations were positively correlated (P<0.05; r = 0.63–0.83) with onset and peak temperatures and enthalpy changes in the RS varieties. Thermal physical properties associated with the RS varieties, including onset and peak temperatures and enthalpy change, may be useful markers for developing future RS products with specific physiological functions and nutritional roles. Supported by Ontario Corn Producers’ Association and OMAFRA of Canada.

Quantitative Assessment of Effective Energy of Resistant Cornstarch Using 13CO2, H2, and CH4 Breath Tests

We calculated the effective energy of a resistant cornstarch (HB-450) by using 13CO2, H2, and CH4 breath tests to assess HB-450 digestion and fermentation in healthy female subjects. On the basis of the areas under the curves (AUCs) for the concentrations of 13CO2 and H2 following ingestion of 40 g of HB-450, 23.0±6.8 g was digested in the upper digestive tract and 3.6±2.1 g was fermented by intestinal flora. The effective energy of the 40 g dose was thus calculated as 2.5±0.8 kcal/g. These results indicate that 13CO2, H2, and CH4 breath tests are useful for measuring the effective energy of resistant cornstarch.

A Combined 13CO2/H2 Breath Test Can Be Used to Assess Starch Digestion and Fermentation in Humans

Ingestion of starch from corn (naturally enriched with (13)C) should produce (13)CO(2) after small intestinal digestion and (13)CO(2) and H(2) from colonic fermentation. This study used a combined (13)CO(2)/H(2) breath test to assess the digestion and fermentation of resistant starch and to show that the test could detect changes in digestibility due to cooking. Volunteers consumed 40 g digestible cornstarch with water (n = 8), or 40 g resistant cornstarch in liquid (n = 12) or cooked into a pancake (n = 4). Interval breath sampling was performed and analyzed for (13)CO(2) and H(2). Ingestion of resistant starch produced a double-peaked (13)CO(2) excretion curve. The first increase in (13)CO(2) occurred at the same time as excretion from digestible starch (55 +/- 9 and 68 +/- 9 min, respectively), which was due to small intestinal digestion. The second increase in (13)CO(2) was accompanied by an increase in H(2) excretion (432 +/- 15 and 428 +/- 48 min, respectively), which was indicative of colonic bacterial fermentation. Cooking resistant starch increased its degree of digestion from 36 to 72%. The (13)CO(2)/H(2) breath test can be used to estimate digestion and fermentation of starches in different physiologic and pathologic conditions.

Resistant Starch Supplementation Influences Blood Lipid Concentrations and Glucose Control in Overweight Subjects

Resistant starch (RS) includes the sum of starch and degradation products of starch that resist small intestinal digestion and enter the colon. This study was planned to examine the effect of resistant starch on hypolipidemic actions, blood glucose, insulin levels and humoral immune responses in healthy overweight subjects. Healthy overweight subjects (over 120% of their ideal body weights) were fed either 24 g/d of resistant corn starch (RS) or regular corn starch (CS) for 21 d with their regular meals. Although this double-blind feeding regiment resulted in no significant changes in their weights or other physical parameters for the relatively acute period of intakes, there were significant lowering effects of serum total cholesterol (p < 0.05) and serum LDL-cholesterol (p < 0.05) in subjects supplemented RS. Compared with the control starch group, the RS supplementation also reduced the mean fasting serum glucose concentrations (p < 0.05). Resistant starch supplement resulted in the increase in serum immunoglobulin G (IgG) concentrations. Serum insulin and complement 3 (C3) were unaffected. Tested resistant starch supplementation was reported to be palatable with minimal bowel discomfort. These results suggest that RS supplementation improves the blood lipid profile and controls the blood glucose levels in healthy overweight subjects without bowel discomfort. Therefore, RS has a potential to be used as one of the promising food ingredients for reducing risk factors involved in the development of atherosclerosis and type 2 diabetes in overweight individuals. However, in order to prove RS as a novel therapeutic agent of cardiovascular diseases and diabetes, controlled trials with larger sample sizes and longer duration are warranted.

Effect of non-digestible oligosaccharides on gut microecosystem in rats

Effect of commercial or new-developed preparations of non-digestible oligosaccharides: fructo-oligosaccharides, lactulose, corn dextrins and corn resistant starch, on microecology of Wistar rats was investigated. A control group was fed a casein diet with 10% cellulose. The experimental groups were administered diets in which cellulose was replaced by the examined preparations. After 4-week feeding experiments, a high increase in live bifidobacteria number by 1.2 and 1.4 log cfu/g of faeces was found in groups fed resistant starch and lactulose. An increase in coliform number by 0.6–0.8 log cfu/g was found in all the groups. No or only negligible changes in numbers of the total mesophilic aerobic and facultatively anaerobic bacteria count, and the spores of anaerobic and aerobic bacteria, were observed. Fructo-oligosaccharides and lactulose lowered pH and gave the best trophic effect in caecum (significantly increased weights of: caecum with contents, cecal walls and cecal contents as well as dry weight of contents), whereas resistant starch increased markers of unhealthy cecal changes (N-NH 3 content and β-glucuronidase activity). The activity of bacterial saccharolytic enzymes changed in a substrate-specific manner in relation to the examined non-digestible oligosaccharide preparations.

Small-intestinal digestion of partially resistant cornstarch in healthy subjects

The aims of this study were to measure the amount of starch from partially resistant starches (retrograded and complexed high-amylose cornstarches) escaping small-intestinal digestion in healthy humans by use of an intubation method and to compare these data with data obtained by indirect in vitro methods. Experiments were carried out in vivo in 6 healthy humans by using ileal intubation and stool analysis and in vitro by using 3 different methods for analyzing resistant starch. In intubated subjects, 51 +/- 2% of the retrograded and 21 +/- 2% of the complexed starch was delivered to the ileum and was fermented almost completely in the colon. In vitro estimates of the absorption of resistant starch were much lower. We conclude that technologically modified starches may substantially increase the amount of carbohydrate available for colonic fermentation in humans, but that in vitro measurements of resistant starch are inaccurate for predicting malabsorption in healthy humans.

Effects of a diet rich in resistant starch on hepatic lipid metabolism in the rat

The aim of this study was to examine the effects of the replacement of a large part of absorbed glucose by volatile fatty acids on hepatic lipid metabolism. For this purpose, experiments were conducted in rats fed either a diet containing digestible wheat starch or amylase-resistant cornstarch. Compared with the digestible wheat starch diet, plasma insulin was lower in rats fed the resistant cornstarch diet, and the fluctuations of insulinemia during the fed/postabsorptive period were smaller. The marked reduction of hepatic lipogenesis in rats fed the resistant cornstarch diet ( −52% compared with the digestible wheat starch diet) resulted from the coordinated inhibition of all major enzymes implicated in the lipogenic pathway, except acetyl CoA synthetase activity. This suggests that volatile fatty acids, particularly acetate, constituted the major source of acetyl CoA for lipogenesis, rather than glucose. However, these modifications were not accompanied by a significant depressive effect on plasma triglycerides. In rats fed the resistant cornstarch diet, changes in lipogenesis activity were accompanied by a reduction of glycolysis as shown by the net inhibition of glucokinase and pyruvate kinase. In parallel to these modifications, with the resistant cornstarch phosphoenolpyruvate carboxykinase was markedly induced; with this diet, propionate should constitute the major gluconeogenic substrate removed by the liver. HMG CoA reductase was markedly induced in rats adapted to the resistant cornstarch diet (1.6-fold higher than with the digestible wheat starch diet); this could be related to the increased fecal bile acids excretion. A significant hypocholesterolemic effect of the resistant cornstarch diet was only observed during the postabsorptive period. In conclusion, hepatic fatty acid synthesis is tightly controlled by carbohydrate availability, but the possibility that volatile fatty acids exert specific effects on lipogenesis could not be ruled out.

Replacement of Digestible Wheat Starch by Resistant Cornstarch Alters Splanchnic Metabolism in Rats

Splanchnic metabolism was investigated in rats fed either a diet containing highly digestible wheat starch (DS diet) or amylase-resistant cornstarch (RS diet). In rats fed the latter diet, there was a considerable enlargement of the cecum and an increase in the production and absorption of volatile fatty acids (VFA), chiefly acetic and propionic acids. As a result, the major substrates absorbed from the digestive tract were glucose in rats fed the DS diet and both glucose and VFA in rats fed the RS diet. The liver removed about one-third of the absorbed glucose in rats fed the DS diet, whereas there was a slight release of glucose by the liver in rats fed the RS diet. Plasma insulin was higher in rats fed the DS diet, and there were smaller fluctuations of plasma insulin and liver glycogen between the fed and postabsorptive periods in rats adapted to the RS diet. In these animals, propionate was the major VFA taken up by the liver and ∼50% of absorbed acetate was also removed by the liver. During the postabsorptive period, there was still a substantial contribution of VFA, especially propionate, to liver metabolism. A depressive effect of the RS diet on plasma triglycerides, cholesterol and free fatty acids was observed only during the postabsorptive period. Replacement of a large part of absorbed glucose by VFA apparently allows time for absorption of energy fuels to be extended and dampens the fluctuations of glucose metabolism during the light: dark cycle.