Influence of genotype and processing on the in vitro rate of starch hydrolysis and resistant starch formation in peas (Pisum sativum L.).

The formation of resistant starch (RS) and the rate of starch hydrolysis were evaluated in vitro in a wild type of green-seeded pea genotype RRRbRb BC3 (33-Am) with 32.7% amylose content and in two mutants RRrbrb BC3 (23-Am) and rrRbRb BC3 (65-Am) with amylose contents of 23.3 and 65.1%, respectively. Pea samples were intact or homogenized and subjected either to autoclaving or to boiling at atmospheric pressure. The amount of RS (total starch basis) varied from 6.2 to 12.9% in the 23-Am products and from 31.2 to 33.4% in the 65-Am products. The RS level of the 33-Am product with a regular amylose content was 11.0%. Both the 23-Am and the 65-Am products were abundant sources of dietary fiber (39 and 34%, dry matter basis, respectively) versus 23% in the regular pea product. The amylose/amylopectin ratio was an important determinant of the rate of starch hydrolysis. The hydrolysis indices (HI) and predicted glycemic indices were lowest in the 65-Am peas (HI range = 42-59) as compared to the 23-Am peas (HI range = 53-84). It is concluded that the pea genotypes covered a wide range in starch availability, which is likely to affect nutritional parameters such as glycemic responses and colonic delivery of starch.     

喷雾干燥工艺对香蕉抗性淀粉保留率的影响(简报)

该文就喷雾干燥中香蕉浆液浓度、进料速度、进风温度3个工艺参数对香蕉抗性淀粉保留率的影响进行研究,采用二次回归正交旋转组合和响应面优化喷雾干燥条件,建立香蕉抗性淀粉保留率随香蕉浆液浓度、进料速度、进风温度变化的标准回归模型,分析三者对香蕉抗性淀粉保留率的影响规律。结果显示：进风温度对香蕉抗性淀粉的保留率影响最大,其次是进料速度,而香蕉浆液浓度影响最小;当香蕉浆液浓度为10.66%、进料速度为14.70 mL/min 、进风温度为156.88℃时,香蕉抗性淀粉的保留率最高,为93.80%,产品品质良好。     

喷雾干燥工艺对香蕉抗性淀粉保留率的影响

该文就喷雾干燥中香蕉浆液浓度、进料速度、进风温度3个工艺参数对香蕉抗性淀粉保留率的影响进行研究,采用二次回归正交旋转组合和响应而优化喷雾干燥条件,建立香蕉抗性淀粉保留率随香蕉浆液浓度、进料速度、进风温度变化的标准回归模型,分析三者对香蕉抗性淀粉保留率的影响规律.结果显示:进风温度对香蕉抗性淀粉的保留率影响最大,其次是进料速度,而香蕉浆液浓度影响虽小;当香蕉浆液浓度为10.66% 进料速度为14.70mL/min、进风温度为156.88℃时.香蕉抗性淀粉的保留率最高,为93.80%,产品品质良好.     

Characterization of water binding and dehydration in gelatinized starch

Using near-infrared spectroscopy and thermogravimetry coupled with differential scanning calorimetry (TG-DSC), we investigated the characteristics of water in starch and the effects of the inner structure of starch on dehydration. The results directly show that the dehydration process is significantly more favorable in native starch than in gelatinized starch. When the starch was heated to 100 °C, the water retention in gelatinized starch was 22.35 per total water content, much greater than that in native starch (4.3%). The hydrogen bond network that changes from native starch to gelatinized starch was simultaneously explored, and the weaker hydrogen bonds were found to be predominant in the hydrogen bond network of gelatinized starch.     

Mango starch degradation. II. The binding of alpha-amylase and beta-amylase to the starch granule

During mango ripening, soluble sugars that account for mango sweetening are accumulated through carbon supplied by both photosynthesis and starch degradation. The cultivar Keitt has a characteristic dependence on sugar accumulation during starch degradation, which takes place during ripening, only a few days after detachment from the tree. Most knowledge about starch degradation is based on seeds and leaves currently used as models. However, information about the mango fruit is scarce. This work presents the evaluation of alpha- and beta-amylases in the starch granule surface during fruit development and ripening. Extractable proteins were assayed for amylase activity and detected by immunofluorescence microscopy and correlated to gene expression. The results suggest that both amylases are involved in starch degradation during mango ripening, probably under the dependence of another signal triggered by the detachment from the mother-plant.     

Effects of resistant potato starch on odor emission from feces in Swine production units

Odor emission from swine facilities is determined by microbial breakdown of amino acids or carbohydrates in the pig colon. It was the aim to influence apoptosis and thus amino acid availability for odor formation by feeding resistant starch (300 g kg(-1) feed) over the whole fattening period to 40 pigs. Concentrations of 12 key components (indoles, volatile fatty acids, methanethiol) were measured in feces and headspace over the slurry duct and compared to 40 normally fed controls in a separate compartment. Concentrations of substances resulting from amino acids were reduced in feces by 70% (indoles) and 8% (branched chain fatty acids) and in the headspace by 72% and 20%. Resistant starch only led to minor increases of straight chain fatty acid concentration. Maximal reduction occurred for 3-methyl-1H-indole (skatole) which is the main determinant of malodor so that the results point to promising strategies for reducing pig odor emission.     

Effects of dietary anthocyanins on tocopherols and lipids in rats

The effects of dietary cyanidin-3-O-glucoside (C3G) and concentrates from blackcurrant [Ribes nigrum] (BC) and elderberry [Sambucus nigra] (EC) on plasma and tissue concentrations of alpha- (alpha-T) and gamma-tocopherol (gamma-T) and cholesterol, as well as the fatty acid composition of the liver lipids were investigated in growing, male rats of the Sprague-Dawley strain. Animals were fed semisynthetic diets supplemented with 2 g/kg C3G, BC, or EC for 4 weeks. Dietary anthocyanins did not affect feed intake, body weight, and organ weights. C3G elevated the concentrations of tocopherols in the liver and lungs (P < 0.05). Cholesterol levels in plasma and liver were not affected by any of the regimens. C3G and BC reduced the relative amount of saturated fatty acids in the liver (P < 0.05). BC also lowered the percentage of 22:6 + 24:0 and EC the ratio of 20:3/20:4 n-6 (P < 0.05). In conclusion, dietary C3G, BC, and EC appear to have little effect on cholesterol levels and the fatty acid pattern in the liver but seem to be capable of sparing vitamin E in healthy, growing rats.     

Regulatory effect of amino acids on the pasting behavior of potato starch is attributable to its binding to the starch chain

The binding of an amino acid, glycine (Gly), alanine (Ala), epsilon-aminocaproic acid (-AC), monosodium glutamate (GluNa), or lysine (Lys), to starch was examined by a biomolecular interaction analyzer (IAsys). A starch sample (ATS) hydrolyzed to an extent of 1% hydrolysis rate with 15% sulfuric acid was used as a model starch for the binding examination. The reducing end of ATS was oxidized by the Somogyi reagent, and the conversion of the reducing end to the carboxyl group of ATS was confirmed by a carboxylic acid fluorescence labeling reagent. The oxidized ATS was immobilized to the amino group of a sensor cuvette by using water-soluble carbodiimide and N-hydroxysuccinimide through an amide bond. The IAsys examination showed that Gly, Ala, and epsilon-AC scarcely bound to the immobilized starch chains but that GluNa and Lys favorably bound with their increasing concentrations. The relative binding index (RBI) of each amino acid was defined by the ratio of the slope of the linear regression equation between the binding response and the concentration for each amino acid to that for Gly. Because the relationships between the RBI and the pasting characteristics (pasting temperature, peak viscosity, breakdown, and swelling index) could each be expressed by a linear regression equation with a high correlation coefficient, it is concluded that the regulation of the pasting behavior of starch with an amino acid is caused by binding of the amino acid to the starch chains.     

Effects of resistant starch type III polymorphs on human colon microbiota and short chain fatty acids in human gut models

This study probed the possible effects of type III resistant starch (RS) crystalline polymorphism on RS fermentability by human gut microbiota and the short chain fatty acids production in vitro. Human fecal pH-controlled batch cultures showed RS induces an ecological shift in the colonic microbiota with polymorph B inducing Bifidobacterium spp. and polymorph A inducing Atopobium spp. Interestingly, polymorph B also induced higher butyrate production to levels of 0.79 mM. In addition, human gut simulation demonstrated that polymorph B promotes the growth of bifidobacteria in the proximal part of the colon and double their relative proportion in the microbiota in the distal colon. These findings suggest that RS polymorph B may promote large bowel health. While the findings are limited by study constraints, they do raise the possibility of using different thermal processing to delineate differences in the prebiotic capabilities of RS, especially its butryrogenicity in the human colon.     

Effect of dietary protein quantity and quality on the brain protein synthesis rate in ovariectomized female rats

The purpose of this study was to determine whether the quantity and quality of dietary protein affected the rate of brain protein synthesis in ovariectomized female rats. Two experiments were conducted on the ovariectomized female rats (12 weeks old) given diets containing 20%, 5%, or 0% casein (experiment 1) and 20% casein, 20% soy protein, 20% gluten, or 20% gelatin (experiment 2) for 10 d, respectively. The fractional rates of protein synthesis in the brain declined with a decrease of the quantity and quality of dietary protein. In the brain, the RNA activity [g of protein synthesized/((g of RNA) d)] was significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg of RNA/g of protein) was not related to the fractional rate of protein synthesis in any organ. The results suggest that the rate of protein synthesis in the brain declines with the decrease of the quantity and quality of dietary protein in ovariectomized female rats, and that RNA activity is at least partly related to the fractional rate of brain protein synthesis.     

Increased frequency of drought reduces species richness of enchytraeid communities in both wet and dry heathland soils

Studies of biological responses in the terrestrial environment to rapid changes in climate have mostly been concerned with above-ground biota, whereas less is known of belowground organisms. The present study focuses on enchytraeids (Oligochaeta) of heathland ecosystems and how the enchytraeid community has responded to simulated climate change in a long-term field experiment. Either increased temperature or repeated drought was applied for 13 years to field plots located in Wales, The Netherlands and Denmark representing a gradient in precipitation and annual temperature fluctuations thereby providing an opportunity to study biological responses on a local (within sites) and regional scale. Warming treatments increasing night-time temperature (0.5–1 °C higher than ambient at 5 cm soil depth) had no detectable effects on the enchytraeid communities. Increased intensity and frequency of drought had rather weak persistent effects on total enchytraeid abundance suggesting that ecosystem functions of enchytraeids may only be transiently impacted by repeated spring or summer drought. However, drought treatment had persistent negative effects on species richness and community structure across sites. Drought treated plots harboured only 35–65% of the species present in control plots, and the reduction of species richness was most pronounced at the driest sites. It is discussed that soil invertebrates, due to their weak migratory potential, may be more liable to extinction under changing climatic conditions than above-ground species, and therefore consequences of climate change to soil organisms need particular attention in future research.     

Flavor improvement in pork from barrows and gilts via inhibition of intestinal skatole formation with resistant potato starch

Skatole originates from microbial processing of tryptophan in the large intestine of pigs and accumulates in adipose tissue. Formation may be inhibited by the anti-apoptotic function of butyrate formed out of raw potato starch. Two groups of pigs (each consisting of gilts and barrows) were fed from 30 to 110 kg life weight either a conventional diet (controls; n = 35) or an isocaloric diet containing 300 g of raw potato starch/kg of body weight (RS; n = 34). Skatole concentrations were measured in colon content, blood, and adipose tissue. Odor of cooked meat samples was evaluated by a test panel. RS reduced concentrations in colon content and blood plasma (P < 0.001). Back fat concentrations were decreased significantly from 25 to 1.40 ng/g (barrows; P < 0.001) and from 40 to 9 ng/g (gilts; P < 0.001). Odor rating (scale of 1-5 from very unpleasant to very pleasant) was 3.07 for low skatole concentrations and 2.66 for both medium and high skatole concentrations (P < 0.05).     

Regulative actions of dietary soy isoflavone on biological antioxidative system and lipid metabolism in rats

Male Sprague-Dawley rats, 4 weeks of age, were fed purified diets either with or without 0.2% soy isoflavones rich powder for 5 weeks to elucidate their direct functions such as antioxidative action and regulation of lipid metabolism. Dietary soy isoflavones decreased serum lipid peroxide level in rats. Levels of liver and serum alpha-tocopherol were higher in the rats fed isoflavone than in those fed isoflavones-free diet. Thus, dietary soy isoflavones exhibited mild antioxidative function in this animal experiment. Isoflavone metabolites from diet may act as scavengers of reactive oxygen species. Dietary soy isoflavones lowered hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity, although liver cholesterol level was not modulated. However, the levels of serum cholesterol and triglyceride decreased by consumption of soy isoflavones. Therefore, dietary soy isoflavones may exhibit hypocholesterolemic and hypolipidemic functions. Moreover, dietary soy isoflavones lowered hepatic Delta6 desaturase activity. Reflecting this observation, Delta6 desaturation indices ((18:2(n = 6) + 18:3(n = 6))/20:4(n = 6)) of tissue lipids tended to be lower in rats fed isoflavones than in those fed isoflavones-free diet. This action may contribute to the prevention of inflammatory response by imbalance of eicosanoids. These observations suggest that the positive intake of soy isoflavones may reduce the risk of some cardiovasucular diseases through their radical scavenging function and hypocholesterolemic action.     

Effect of long-term dietary administration of oregano on the alleviation of carbon tetrachloride-induced oxidative stress in rats

This study aimed at evaluating the protective effect of long-term dietary oregano on the alleviation of carbon tetrachloride-induced oxidative stress in rats. Twenty-four female Wistar rats were allocated to four groups of six animals each. Groups 1 (control) and 2 (CCl 4) were fed a basal diet, while groups 3 (oregano) and 4 (oregano + CCl 4) were fed the basal diet supplemented further with ground oregano at 1% level. Following six-week feeding, the rats of groups 2 and 4 were given a single intraperitoneal injection of CCl 4 at a dose of 1 mL/kg bw. Six hours after the CCl 4 injection, all animals were sacrificed, and serum, liver, kidney, and heart tissue samples were collected. Analysis results showed that the addition of oregano significantly increased the total phenolic content and the Trolox equivalent antioxidant capacity of the basal diet but had no effect on its lipid peroxidation index. Treatment with CCl 4 of rats from the CCl 4 group caused a significant increase in aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) in serum, whereas it decreased cholesterol and triglyceride content as compared to the control. It also increased the lipid peroxidation index and decreased the scavenging activities of the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS) radical cation, the hydroxyl anion radical, the superoxide anion radical, and the hydrogen peroxide in all tested tissues, as compared to that of the control. Without CCl 4 treatment, diet supplementation with oregano had no effect on these biochemical parameters, excluding the hydroxyl radical scavenging activity, which was increased in all tested tissues as compared to that of the control. Feeding oregano before CCl 4 treatment resulted in a significant decline of the increase in AST, ALT, and ALP activities ( P < 0.05 vs CCl 4 group), but the recorded values could not attain those of the control group ( P < 0.05 vs control group). It significantly increased the reduced cholesterol and triglycerides ( P < 0.05 vs CCl 4 group) to values not differing from those of the control. It also resulted in a significant reduction of the increased malondialdehyde ( P < 0.05 vs CCl 4 group) to values that could not attain the levels of the control but had no significant effect ( P > 0.05) on the reduced ABTS radical cation scavenging activity. It increased significantly the reduced hydroxyl anion radical scavenging activity ( P < 0.05 vs CCl 4 group) to values that could not attain those of the control in all tested tissues except kidney. Additionally, it resulted in a significant elevation of the decreased superoxide anion radical scavenging activity in serum and liver but had no effect in kidney and heart, whereas it also resulted in a significant elevation of the decreased hydrogen peroxide scavenging activity in liver, kidney, and heart but had no effect in serum. These results suggest that dietary oregano may effectively improve the impaired antioxidant status in CCl 4-induced toxicity in rats.     

An oral colon-targeting controlled release system based on resistant starch acetate: synthetization, characterization, and preparation of film-coating pellets

An oral colon-targeting controlled release system based on resistant starch acetate (RSA) as a film-coating material was developed. The RSA was successfully synthesized, and its digestion resistibility could be improved by increasing the degree of substitution (DS), which was favorable for the colon-targeting purpose. As a delivery carrier material, the characteristics of RSA were investigated by polarized light microscopy, FTIR spectroscopy, and X-ray diffraction. The results revealed a decrease of the crystallinity of RSA and a change of its crystalline structure from B + V hydrid type to V type. To evaluate the colon-targeting release performance, the RSA film-coated pellets loaded with different bioactive components were prepared by extrusion-spheronization and then by fluid bed coating. The effects of the DS, plasticizer content, and coating thickness of the RSA film and those of the content and molecular weight of the loaded bioactive component on the colon-targeting release performance of the resulting delivery system were investigated. By adjusting the DS, the coating thickness, and the plasticizer content of the RSA film, either the pellets loaded with a small molecular bioactive component such as 5-aminosalicylic acid or those with a macromolecular bioactive peptide or protein such as bovine serum albumin, hepatocyte growth-promoting factor, or insulin showed a desirable colon-targeting release performance. The release percentage was less than 12% in simulated upper gastrointestinal tract and went up to 70% over a period of 40 h in simulated colonic fluid. This suggests that the delivery system based on RSA film has an excellent colon-targeting release performance and the universality for a wide range of bioactive components.     

Health-promoting effects of a dietary fiber concentrate from the soybean byproduct okara in rats

Okara (a byproduct of the soy milk industry) is rich in proteins (24.5-37.5 g/100 g of dry matter (dm)), lipids (9.3-22.3 g/100 g of dm), and dietary fiber (DF) (14.5-55.4 g/100 g of dm). It also contains isoflavones (0.14 g/100 g of dm). In the present study we fed female healthy Wistar rats either a standard rat diet or a supplemented 10% DF-rich okara (DFRO) diet for 4 weeks, and then we assessed several health parameters in the serum and the cecum compartments. In comparison to the control group, rats fed DFRO showed a significant decrease in weight gain (5.00 +/- 1.22 g vs 2.00 +/- 1.46 g, P < 0.03, during week 4) and in total cholesterol (65 +/- 8 mg/dL vs 51 +/- 5 mg/dL, P < 0.05) and a significantly increased antioxidant status (36.71 +/- 15.31 micromol of Trolox equivalents (TEs)/g vs 69.75 +/- 16.11 micromol of TEs/g, P < 0.0003) and butyrogenic effect (39.37%, P < 0.003) in the cecum. In addition, a significant enhancement in the apparent absorption (41.89 +/- 1.64% vs 47.02 +/- 2.51%, P < 0.004) and in the true retention (41.62 +/- 1.60% vs 46.68 +/- 2.55%, P < 0.005) of calcium was appreciated. In summary, these findings show for the first time that a concentrate DF from a soybean byproduct protects the gut environment in terms of antioxidant status and prebiotic effect. These results may highlight the development of an innovative soybean byproduct rich in DF which could be useful as a functional ingredient with health-promoting attributes.     

The effect of dietary fiber from wheat processing streams on the formation of carboxylic acids and microbiota in the hindgut of rats

Colonic fermentation of dietary fiber produces carboxylic acids and may stimulate the growth of beneficial bacteria. This study investigated how byproducts of wheat processing (distillers' grains and two fractions from the wet fractionation to starch and gluten, one of which was treated with xylanase) affect the composition of the cecal microbiota and the formation of carboxylic acids in rats. Differences were mostly found between diets based on supernatants and pellets, rather than between fiber sources. Cecal pools and levels of most carboxylic acids in portal blood were higher for rats fed the supernatant diets, while cecal pH and ratios of acetic to propionic acid in portal blood were lower. The diet based on supernatant from distillers' grains gave the highest level of bifidobacteria. Molecular weight and solubility are easier to modify with technological processes, which provides an opportunity to optimize these properties in the development of health products.     

Effect of dietary high-oleic-acid oils that are rich in antioxidants on microsomal lipid peroxidation in rats

In contrast to other metabolic functions, the role of dietary antioxidants and oil on microsomal lipid oxidation has been less extensively studied. This study examines ascorbate-Fe(2+) and NADPH-induced lipid peroxidation of hepatic microsomes of rats that were fed for three weeks high-oleic-acid oils (high-oleic sunflower oil, HOSO; olive oil, OO; or olive pomace oil, OPO) containing different concentrations of the antioxidants alpha-tocopherol, erythrodiol, and oleanolic acid. The fatty acid composition of hepatic microsomes of Wistar rats that were fed for three weeks with the above-mentioned oils had lower proportions of C16:0, C18:2n6, and C22:6n3 and higher proportions of C18:0 and C18:1n9 than rats fed the control diet. Light emission by hepatic microsomes increased, in the first 180 min, 2-fold after ascorbate-Fe(2+) addition compared with NADPH addition. Both increases were less pronounced in microsomes of OPO-fed rats and to a smaller extent in microsomes of OO-fed rats. Smaller increases in light emission were associated positively with higher concentrations of dietary alpha-tocopherol, erythrodiol, and oleanolic acid but were not associated with changes in fatty acid composition of hepatic microsomes. Addition of alpha-tocopherol, erythrodiol, or oleanolic acid decreased light emission of hepatic microsomes with a greater inhibition in microsomes of rats fed the control diet. Our data suggest that erythrodiol and oleanolic acids partly explain the protective effect of dietary OPO on microsomal lipid peroxidation in rats.