EFFECT OF DIETARY FIBER ON THE PREVENTION OF LIVER LIPID ACCUMULATION INDUCED BY HIGH POLYUNSATURATED OIL

This study investigated whether dietary fiber can prevent the accumulation of liver lipids due to the ingestion of polyunsaturated oil. Fifteen percent fish oil (FO) was added to the basal diet as a source of polyunsaturated oil. Ten percent cellulose, pectin, guar gum, konjac mannan or gum Arabic was mixed in the diet as a source of dietary fiber. Commercial Purina rat chow was used as a control and a fiber-free (blank) diets were also employed in the study. Each experimental diet was fed to each group of 6 Wistar rats for 8 weeks. Fish oil feeding lowered the plasma triacylglycerols (TG) and cholesterol (CS) levels. Rats fed a fiber-free diet had higher liver weights indicating hepatomegaly and a marked accumulation of liver lipids. With the exception of cellulose and gum Arabic, the inclusion of dietary fiber in FO diets lowered the plasma total lipids and CS; plasma TG was unchanged. Pectin and guar gum enhanced the CS-lowering effect of the FO diet. All of the test fibers, but especially pectin and guar gum, reduced the accumulation of total lipids, TG and CS in rat liver caused by dietary FO. Hepatic glucose-6-phosphate dehydrogenase activity was reduced in rats fed FO, but dietary fiber had no effect on the activity of this enzyme.     

不同品种膳食纤维影响小鼠糖耐量结果的比较

本文选择多功能大豆纤维（MSF）、小麦纤维、纤维素、果胶和瓜儿胶等5种膳食纤维，对其影响小鼠葡萄糖耐量结果作了比较与分析。结果显示，1.0g/kg MSF、果胶或瓜儿胶可使葡萄糖耐量曲线变得尤为平缓，而同剂量纤维素和小麦纤维的效果并不显著。水溶性、粘性膳食纤维具有明显的稳定餐后血糖的作用，原因可能在于它能增加小肠内容物粘性，增加肠内非搅动层（unstirred layer）的厚度，并能使胃的排空速率降低，从而显著降低葡萄糖吸收速度。     

Determination of Pectin in the Presence of Food Polysaccharides

A selective and specific method to assay pectin in mixtures of polysaccharides using pectinase was developed. The mixture was extracted with 99.5% (v/v) ethanol to remove gum arabic and any other ethanol-soluble saccharides and polysaccharides; pectin was then hydrolyzed with pectinase. The hydrolyzed pectin was recovered by solution in 80% (v/v) ethanol and assayed by the m-hydroxybiphenyl method. The assay was not affected by agar and gums of tragacanth, karaya, guar, and locust bean in the mixture. Alginate and xanthan gum in the mixture repressed the development of color by this method, but this effect could be offset by modification of the pectinase reaction system.     

Effect of Dietary Fiber Constituents on the In Vitro Digestibility of Casein

The in vitro digestibility of casein was substantially decreased by food type gums in the following order: karaya > ghatti > tragacanth > guar > locust bean. Extent of reduction of protein digestibility appeared to be related to the structure of the gum (degree of branching and extent of ionization). The fiber constituents, holocellulose, lignin, apple pectin, and the residues from protease predigested wheat bran and great northern bean, when present, significantly (P < 0.05) reduced casein digestibility. Gel filtration of the soluble portion from the casein hydrolysates containing pectin and bran or bean residues showed the presence of peptide fractions of larger molecular weight than those in a hydrolysate from the casein control. Results supported the hypothesis that dietary fiber constituents may reduce protein digestibility and increase nitrogen excretion through ionic interaction, matrix restriction, and modification of filtration characteristics by the fiber components tested.     

Dietary Fiber Binding of Bile Acid through Mineral Supplementation

Iron and/or calcium were added to psyllium, guar gum, locust bean gum, citrus rag, high methoxy pectin, and low methoxy pectin. This mixture was then incubated with either cholic acid, deoxycholic acid, glycocholic acid, or taurocholic acid to evaluate the effect of minerals on fiber-bile acid binding. The addition of iron with or without calcium increased the binding of deoxycholic acid to all fibers (p≤0.01 and p≤0.025) except low methoxy pectin. Iron and calcium caused increased binding of high methoxy pectin to all bile acids (p≤0.01 and p≤0.025). Dietary fiber's ability to bind certain bile acids may be maximized through mineral supplementation.     

Effect of some hydrocolloids on the rheological properties of different formulated ketchups

Five different hydrocolloids (tragacanth gum, guar gum, carboxy methyl cellulose, xanthan gum and locust bean gum) were added, at levels of 0, 0.5, and 1 g/100 g (w/w), respectively, to three different formulated ketchups which were processed from cold-break tomato paste dilutions, having total soluble solid (TSS) contents of 7.5, 10, and 12.5 g/100 g (w/w), in sequence, and the effect of these hydrocolloids on the rheological properties of tomato ketchups was investigated using a viscometer with smooth surface wide-gap coaxial cylinders. All hydrocolloids increased the consistency of the tested samples; however, guar gum and locust bean gum caused the maximum increase, followed by xanthan gum, tragacanth gum and carboxy methyl cellulose (CMC). Both the ketchup formulation and the hydrocolloid concentration were found to affect the consistency of ketchups. The highest consistency index was obtained by processing dilutions with a TSS content of 12.5%, and the addition of hydrocolloids at the level of 1%. The fluidity of the ketchups decreased with both the addition of all hydrocolloids and the increase in hydrocolloids concentration. Furthermore, the fluidity of the ketchups was also affected by ketchup formulation, and it was found to be the lowest for the samples prepared from the tomato paste dilutions having a TSS content of 12.5%.     

Factors Affecting Adhesion of Coating to Poultry Skin: Effects of Various Protein and Gum Sources in the Coating Composition

Breading losses from poor adhesion of coating to food products is a major concern in the battered and breaded foods industry. The primary aim of this study was to determine effects of protein and gum sources and amounts on the adhesion of a commercial breading mix to poultry skin. Protein sources used were whey, soy, nonfat dry milk, egg albumen, and gelatin. Gum sources were sodium carboxymethyl cellulose (CMC), guar, tragacanth, and xanthan. Among the proteins, gelatin and egg albumen most effectively improved adhesion. For all gums studied, only CMC was significantly better at improving adhesion. Increased levels of gums and proteins in breading did not affect adhesion significantly.     

Mineral Binding Characteristics of Lignin, Guar Gum, Cellulose, Pectin and Neutral Detergent Fiber under Simulated Duodenal pH Conditions

Effective stability constants (K_cff) and amount of Fe bound by lignin, cellulose, guar gum, low and high methoxy pectin and NDF were determined under simulated duodenal pH conditions. Guar gum bound 8.4 μmol Fe per g fiber with the greatest affinity (K_cff= 6.27 × 10⁶) of any of the fibers studied; NDF, high methoxy pectin, and one of the binding sites of lignin bound 5.0. 5.0, and 19.5 μmol Fe, respectively. per g fiber, with a K_cff > 10⁵, and cellulose bound Fe so weakly that an effective stability constant could not be calculated. Lignin had two distinct binding sites for Fe, Zn, and Cu with the high affinity sites binding in the following order: Fe > Cu > Zn, but with twice as much Cu bound as either Fe or Zn.     

Production of short‐chain fatty acids following in vitro fermentation of saccharides,saccharide esters,fructo‐oligosaccharides,starches, modified starches and non‐starch polysaccharides

A range of carbohydrates including modified starches and short‐chain fatty acid esters of di‐, tri‐, tetra‐ and polysaccharides were subjected to an in vitro fermentation using human‐derived faecal bacteria. The production of the short‐chain fatty acids (SCFAs) acetate, propionate and butyrate was monitored at 6, 12, 24 and 36 h for all substrates; however, it was found that the proportions of acids produced were reasonably constant after 6 h. Between substrates there was variation in both the proportions and quantities of acids produced. Relative substrate fermentability as measured by total acid production at 24 h was: sucrose octa‐acetate > sucrose > stachyose > pregelatinised starch > Raftilose^® > verbascose > raffinose > starch acetate > bleached starch > phosphated distarch phosphate > locust bean gum > corn starch > oxidised starch = starch sodium octenyl succinate > di‐starch phosphate > acetylated di‐starch adipate = gum arabic > acid‐treated starch > gum tragacanth > gum guar > acetylated di‐starch phosphate = hydroxypropyl di‐starch phosphate > hydroxypropyl starch > pectin > raffinose undeca‐acetate > stachyose acetate > gum karaya = cellulose propionate > cellulose acetate > cellulose > cellulose butyrate > hydroxypropyl methyl cellulose > carrageenan > methyl cellulose. Chemically modified starches were similar to corn starch in the amounts of total SCFAs produced at 24 h. Synthetic sugar esters could have potential application as vehicles to deliver supraphysiological amounts of SCFAs during in vivo studies of colonic fermentation. © 2000 Society of Chemical Industry     

Effect of pH and Heat Treatment on the Binding of Calcium, Magnesium, Zinc, and Iron to Wheat Bran and Fractions of Dietary Fiber

The effect of pH and heat treatment on the binding of added food grade sources of calcium, magnesium, zinc, and iron to a standard wheat bran, cellulose, and lignin was investigated. 1% solutions of pectin and guar gum were examined for their ability to bind these metals in aqueous solution. Lignin and pectin was found to have high metal binding capacities. Metal binding to fiber was found to be pH dependent. Toasting had no effect on metal binding by cellulose, but had a significant effect on the binding of metals by lignin and wheat bran. Boiling had a significant effect on the binding of metals by cellulose, lignin, and wheat bran.     

Extrusion of corn grits containing various levels of hydrocolloids

Fourteen hydrocolloids, locust bean, agar, guar, alginate, tragacanth, carrageenan, xanthan, pectin, gelatin and Methocels A4M, E4M, F4M and K4M were dry blended with corn grits at levels of 0.1, 0.5 and 1.0%. Twenty percent moisture was added and each product extruded in a Brabender Model PL-V500 laboratory extruder at temperatures of 50, 75, 100, 125 and 150°C with a 1:1 screw operating at 100 rpm. Locust bean, agar, guar, alginate, arabic and Methocels E4M, F4M and K4M significantly lowered torque at an extrusion temperature of 50°C, but did not in general produce significant reductions at higher extrusion temperatures. In contrast, tragacanth, carrageenan, xanthan, pectin, gelatin and Methocel A4M did not significantly reduce torque over the concentrations and conditions evaluated during the extrusion of corn grits. All the Methocel derivatives lowered yield at low extrusion temperatures. No gum significantly increased yield over the entire extrusion temperature range evaluated. Therefore, certain gums can significantly reduce torque without influencing yield during the extrusion of corn grits.     

The effect of viscous substances on the transit time of barley digesta in rats

The influence of a number of hydrocolloids on the transit time of digesta, stool weight and colour of stools was investigated in rats. All hydrocolloids tested gave the stools a lighter colour and increased their size and water content. The hydrocolloids could be divided into two groups according to their action on digesta passage: pectin, gum arabic, oxidised starch and barley β-glucan retarded it, while guar gum, carrageenan, tragacanth gum, carob bean gum, sodium alginate and sodium carboxymethyl cellulose accelerated it. After feeding carrageenan for 1 week it took several weeks before water content and transit time returned to normal. Gum arabic was found to cause caecal distension.     

Sensory Optimization of Broken-Rice Based Snacks Fortified with Protein and Fiber

ABSTRACT:  A 3-component mixture experiment was used to optimize the formulation of broken-rice based snack fortified with protein and fiber based on consumer sensory acceptability. Soy protein isolate and guar gum were used as a good source of protein and fiber, respectively, according to DRV (daily reference value) based on a 2000-calorie diet. A consumer panel evaluated sensory acceptability of color, crispness, and flavor, and overall liking of 12 experimental broken-rice based snack formulations. Predicted models derived from the restricted nonintercept regression analysis were used to plot mixture response surfaces (MRS) of each sensory attribute. Areas within the MRS plots having predicted acceptability scores of at least 6.5 (on a 9-point hedonic scale) for color, crispness, flavor, and overall liking were selected to derive a predicted optimum formulation range. Flavor acceptability was a limiting factor in attaining the optimum formulation range, which consisted of 40% to 48% broken-rice flour, 8% to 16% guar gum, and 20% to 33% soy protein isolate. To verify the obtained predicted models, the formulation containing 48% broken-rice flour, 8% guar gum, and 20% soy protein isolate, which was located in the optimum area, was chosen to support our effort to utilize and add value to broken rice. Selected physicochemical measurements of the chosen optimized formulation were determined. One serving size (30 g) of the chosen optimized snack product provided 6.58 g protein and 3.80 g dietary fiber, which met the US FDA definition of a good source of protein and dietary fiber.     

Effects of pectin and guar gum on creaming stability, microstructure and rheology of egg yolk plasma-stabilized emulsions

The influence of pectin and guar gum on the creaming stability, microstructure and rheological properties of 1.0% (w/v) egg yolk plasma (EYP)-stabilized 25.0% (v/v) soybean oil-in-water emulsions was studied at pH 7.0. Addition of pectin/guar gum decreased creaming percentage, and no creaming was detected in the presence of 0.5% (w/v) pectin/guar gum as a result of increasing viscosity. At the end of 10 h, creaming percentage decreased from 61 to 57% with the addition of 0.05% (w/v) guar gum and to 39% with the addition of 0.2% (w/v) guar gum. Microscopic observations represented the droplet aggregation arising from the presence of nonabsorbing biopolymers. At \mathop g^. \mathop \gamma \limits^{.}  = 10 s⁻¹, a tenfold increase in viscosity was observed in the presence of 0.5% (w/v) guar gum compared to the presence of 0.1% guar gum due to the thickening effect of polysaccharide. Increasing gum concentrations enhanced the viscosity and hence the consistency index. All emulsions, except for those containing 0.5% (w/v) guar gum, reflect the near-Newtonian behaviour with flow behaviour index, n, of 0.9–1.0. All emulsions exhibited a liquid-like behaviour at low frequencies (<7.0 Hz) where G″ values were higher than G′. Both G′ and G″ showed a frequency dependency and these two moduli crossed each other at higher frequencies (>7.0 Hz), G′ became greater than G″ and the system behaved like an elastic solid. Addition of pectin at all levels cause no significant change in G′ and G″ values, whereas addition of guar gum, especially at a concentration of 0.5% (w/v), significantly improved these values.     

复合膳食纤维素的结构及物性研究

采用大豆纤维素为基料,水溶性天然植物胶——瓜尔豆胶、果胶为辅料复合后,制备一种兼有水溶性和非水溶性双重特性的复合膳食纤维素。测定复合膳食纤雏素的粘度和表面张力,并对复合膳食纤维素体系进行扫描电镜观察后发现,大豆纤维素与瓜尔豆胶复合物的粘度和表面张力较两种单一成分均有明显提高,且复合物可调和成为以瓜尔豆胶溶胶为基体、大豆纤维素颗粒均匀镶嵌其间的稳定体系。大豆纤维素与果胶复合物的上述指标也有提高,但体系不稳定。     

Rheological properties of whey protein isolate stabilized emulsions with pectin and guar gum

Dynamic oscillatory and steady-shear rheological tests were carried out to evaluate the rheological properties of whey protein isolate (WPI) stabilized emulsions with and without hydrocolloids (pectin and guar gum) at pH 7.0. Viscosity and also consistency index of emulsions increased with hydrocolloid concentration. At γ = 20 s⁻¹, the value of viscosity of the emulsion with 0.5% (w/v) pectin was about fivefold higher than that of the emulsion without pectin. Flow curves were analyzed using power law model through a fitting procedure. Flow behaviour index of all emulsions except for containing 0.5% (w/v) guar gum was approximately in the range of 0.9–1.0, which corresponds to near-Newtonian behaviour. The shear thinning behaviour of emulsions containing 0.5% (w/w) guar gum was confirmed by flow behaviour index, n, of 0.396. Both storage (G′) and loss modulus (G″) increased with an increase in frequency. Emulsions behaved like a liquid with G″ > G′ at lower frequencies; and like an elastic solid with G′ > G″ at higher frequencies. Effect of guar gum was more pronounced on dynamic properties. Phase angle values decreased from 89 to <10° with increasing frequency and indicated the viscoelasticity of WPI-stabilized emulsions with and without pectin/guar gum.     

Effects of nonprotein substances on protein hydrolysis and plastein formation

Effects of various naturally occurring nonprotein substances (carbohydrates, polysaccharides, fats and salts) on enzymatic hydrolysis of soy protein isolate and plastein formation from hydrolyzed soy protein were investigated. Relative extent of hydrolysis and plastein formation were measured as protein solubility in 10% trichloroacetic acid (TCA) since this method was found suitable for analysis of turbid, viscous and/or low protein samples. The presence of guar, xanthan, locust bean and arabic gums, arabinogalactan, unsaturated fatty acids (2%), salt mixture and xylan were found to enhance soy protein peptic hydrolysis at 0·5% enzyme/substrate; unsaturated fatty acids (1%) inhibited hydrolysis. At enzyme/substrate of 3·5%, hydrolysis was enhanced by xanthan gum, unsaturated fatty acids and sodium chloride but inhibited by gum karaya, salt mixture, starch, cellulose, and saturated fatty acids. Plastein synthesis was inhibited by xanthan, locust bean and guar gums but stimulated by arabinogalactan. Several nonprotein substances were found to interfere with the TCA solubility assay. Positive interference was noted for systems containing saturated and unsaturated fatty acids and magnesium, but negative interference was observed for systems containing guar gum, xanthan gum, calcium chloride and gum arabic.     

湿热-胶体改性对小麦面筋蛋白功能性质的影响

研究了在湿热条件下将羧甲基纤维素钠(CMC)、明胶、海藻酸钠、果胶、瓜尔胶这几种不同胶体作为添加剂添加到小麦面筋蛋白中,测定了其对小麦面筋蛋白功能性质的影响,主要以小麦面筋蛋白的粘稠性、乳化性和乳化稳定性、溶解性、起泡性这几个指标作为参考。实验结果表明,与简单混合相比,羧甲基纤维素钠、明胶、海藻酸钠、果胶在湿热条件下使小麦面筋蛋白的溶解性,乳化性和粘稠性都有一定幅度的提高,但是对小麦起泡性和乳化稳定性的影响不大;瓜尔胶在湿热条件下对小麦蛋白性质的影响与简单混合相比基本持平。     

In vitro binding of calcium,iron and zinc by non-starch polysaccharides

The in vitro binding capacity of eight non-starch polysaccharides (agar, κ-carrageenan, gum xanthan, gum arabic, gum karaya, gum tragacanth, pectin and gum guar) was measured by equilibrium dialysis in neutral and acidic (0.1M HCl) solutions in the presence of divalent cations (Ca²⁺, Zn²⁺). No significant binding was observed in acidic conditions while, in neutral solutions, the extent of binding was correlated (P<0.1) to the cation-exchange capacity of the polysaccharides. It is apparent that the interactions are essentially electrostatic in nature, due to the presence of ionised carboxyl (uronic/pyruvic acids) and sulphated groups, in polyanionic polysaccharides. By contrast, significant binding occurs with Fe³⁺ in acidic conditions, presumably due to complexation (chelation). These data provide a clear insight into how non-starch polysaccharides interact with minerals and the potential nutritional consequence in terms of bioavailability.     

预煎炸冷冻食品锅贴的配方优化

对预煎炸微波冷冻冷冻锅贴面皮的品质改善进行了研究。通过筛选配方配料,确定添加脆性淀粉、瓜尔豆胶、羟甲基纤维素钠、大豆分离蛋白可以提高产品的酥脆性,改善微波复热后的"侵湿"现象,并确定了产品配方:中筋面粉100 g、脆性淀粉10 g、HPMC 1 g、大豆分离蛋白2 g、瓜豆尔胶1.5 g、油2.0 g、盐0.5 g、水50 mL。