OXIDATIVE STABILITY AND VITAMIN ELEVELS INCREASED IN RESTRUCTURED BEEF ROASTS WITH ADDED RICE BRAN OIL1

Crude rice bran oil 0, 1%, and 2% (w/w), was added to restructured beef roasts that were stored at 4C and analyzed at 0, 7, and 14 days to determine nutritional properties and oxidative stability. The saturated fatty acid to unsaturatedfatty acid (SFA/UFA) ratio and the content of 7‐ketocholesterol decreased (p < 0.05) whereas vitamin E vitamers increased (p < 0.05) in the product with 2% rice bran oil. TBARs numbers were lower (p < 0.05) in roasts with rice bran oil after 7 days of storage. The addition of 2% rice bran oil (w/w) was effective in improving both oxidative stability and vitamin E levels.     

Binding of Zinc to Apple Fiber, Wheat Bran, and Fiber Components

Zinc ion binding to commercial brans, fiber, and fiber components was studied by equilibrium dialysis. Maximum initial concentration of zinc bound by 50 ma of apple fiber (AF) and wheat bran (WB) at pH 7.2 was 220 μg. AF and WB binding capacities were significantly lower for soluble fractions than for unfractionated materials. The water-soluble fraction's binding capacity was 90% lower for AF than for WB. Hemicellulase and phytase slightly increased AF binding capacity but reduced WB capacity. Pectinase increased both AF and WB capacity slightly. Binding capacities of commercially available individual fiber components decreased in the order: lignin > polypectin > pectin > gum > cellulose. Zinc-binding capacities of various dietary fiber types differ, accounting for different zinc bioavailabilties of some foods.     

Extraction and Functional Properties of Barley β-Glucan as Affected by Temperature and pH

Barley is high in β-glucan, a soluble fiber component. Effects of extraction temperature (40 55 C) and pH (7.0 10.0) on recovery, purity and functional properties of β-glucan were investigated on whole Condor barley flour. At pH 7.0, 8.0 and 55°C, 86.5% of the β-glucan in the feed flour was recovered in the gum product with 89.1% (d.w.b.) purity. β-Glucan content increased (p < 0.05) with temperature but not with pH. Apparent viscosity of 1% (w/v) dispersions of β-glucan gum from pH 7.0 increased (p < 0.05) with extraction temperature at constant shear rate and viscosity decreased slightly with increasing shear rate. Whippability and foam stability of gums from pH 8.0 and 45°C were maximum. Emulsions prepared with β-glucan gum from pH 7.0 and 55@c were 63% stable after centrifugation. Barley β-glucan shows great potential as a thickener or stabilizer.     

Gelation of Barley ß-Glucan Concentrate

The gel behavior of barley β-glucan (BBG) gum extracted in our laboratory was compared to low- and high-viscosity commercial BBG gum and cornstarch using compression between parallel plates. Effects of β-glucan concentration and hydration temperature on gel behavior were examined. BBG gum gelled at ≥5% concentration and gel strength increased (p≤0.05), but not proportionally, with concentration. Hydration temperature did not influence gel strength. Commercial β-glucan had higher (p≤0.05) gel strength than our BBG gum at 5% concentration. Cornstarch produced ～78% softer gel than BBG gum at 6% concentration. BBG may have potential as a gelling agent.     

VARIOUS DIETARY FIBERS DECREASE THE RATE OF LIPASE-CATALYZED HYDROLYSIS OF OLIVE OIL IN VITRO

An in vitro method was used to evaluate the effect of different types of dietary fiber on the initial rate of hydrolysis of olive oil catalyzed by porcine pancreatic lipase. Lipolysis was measured at pH 6.5 and 37C while stirring at 20 rpm. Excellent recoveries of added known amounts of oleic acid were obtained in control and fiber-containing samples. Dietary fibers tested (all 3% by weight unless otherwise noted) were: red wheat bran, white wheat bran, oat bran, soyfiber, sugarbeet fiber, chitin, chitosan, cellulose, pectin-LM and psyllium seed (1.5%). All inhibited lipolysis (35–85%) except cellulose and pectin. The contribution of aqueous extracts of the insoluble fibers to the total inhibitory properties of the fibers were: 0% for the two wheat brans; 100% for oat bran, chitin, chitosan and sugarbeet fiber; and 63% for soyfiber.     

ADSORPTION of BILE ACIDS ON CEREAL TYPE FOOD FIBERS

A study involving measurement and analysis of adsorption of common bile acids, namely cholic, deoxycholic, and lithocholic acids, on cereal type dietary fibers was conducted. the selected food fibers were oat fiber, rice fiber, barley fiber, corn bran, and wheat bran, which are all extensively used in processed foods. the adsorption data were measured at 37C and 25C, which correspond to approximate human body and room temperatures. Influence of particle size reduction, due to grinding, on a fiber's bile acid binding capacity was examined by using macro size (35–60 mesh) and micro size (100–300 mesh) fibers as adsorbents. the investigation also included the effects of medium pH and the chemical composition. the experimental data were correlated with the Langmuir and the Freundlich isotherms in order to utilize the data in future predictions and simulations.
It was found that the particle size reduction, accompanied by surface area increase, has a significant influence on the adsorption capacity of the fiber. Macro size fibers adsorbed the same bile acid with the following trend: oat > barley > rice > wheat > corn; while micro size fibers followed a somewhat different trend: rice > barley > oat > wheat > corn. This was due to the surface area change after grinding, and a positive correlation between the surface area and the adsorption capacity was observed in each case. the adsorption was favored by acid pH surroundings, and it was positively correlated with the hydrophobicity of the bile acid. were adsorbed on the same fiber with the following trend: lithocholic acid > deoxycholic acid > cholic acid. Fibers adsorbed more bile acid at 25C than they did at 37C. However, the increase in the uptake capacities were not very signipcant.     

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.     

Oat Gum and β-Glucan Extraction from Oat Bran and Rolled Oats: Temperature and pH Effects

The extractability of oat gum from oat bran and rolled oats was studied using 12 treatment combinations in a factorial design (2x3x4x2) i.e. 2 oat products; 3 pH (8.0–10.5); 4 temperatures (5O–70°C); 2 replications. The extraction procedure involved: (a) alkaline treatment of flour and removal of starch residue; (b) isoelectric precipitation of protein residue [namely, protein concentrates (PC)]; (c) and alcohol precipitation of oat gum/β-glucan and collection of gum by centrifu-gation. Extracted oat gum ranged from 2.99–6.28% for oat bran and 1.82–5.24% for rollcd oats whereas β-glucan (in gum) ranged from 70–89% and 50–68%, respectively. Protein contents of the PC from oat bran was 69–91% and rolled oats 66–89%. Correspondingly, starch content of residues ranged from 30–63% and 61–47%. Oat gum/β-glucan extracted at pH 9.2/50°C or pH 10.5/50/55°C showed little or no starch contamination.     

Color of Dehydrated Tomato: Effects of Gum Arabic

The efficacy of gum arabic, as a color preservative and inhibitor of non-enzymatic browning of dehydrated tomato during storage, was studied and compared with sodium metabisulfite. Tomato homogenates were treated with 1, 2.5, 5, 7.5, and 10.0% gum arabic and 1.0% sodium metabisulfite, respectively, dehydrated, and color changes were monitored during four months of storage. Water activity decreased significantly (P ≤ 0.05) and Brix values increased significantly (P ≤ 0.05) in gum arabic-treated samples. pH of metabisulfite treated samples is significantly (P ≤ 0.05) higher than that of control and gum arabic treated samples. Lightness (L*) value increased significantly (P ≤ 0.05) with the addition of 5–10% gum arabic compared to the dehydrated control. Browning index of dehydrated tomato decreased significantly (P ≤ 0.05) with the treatments, 1 and 2.5% Gum Arabic, 1% metabisulfite, 5, 10, and 7.5% gum arabic, respectively. Gum arabic at 5–10% (w/w) was more suppressed to browning than sodium metabisulfite. Gum arabic preserved color of dehydrated tomatoes up to 4 months of storage.     

Sensory Acceptability of Foods with Added Lupin (Lupinus angustifolius) Kernel Fiber Using Pre-set Criteria

ABSTRACT: Fiber-enriched white bread, muffin, pasta, orange juice, and breakfast bar were prepared with lupin ( Lupinus angustifolius ) kernel fiber. Consumer panelists (n = 44) determined that all these fiber-enriched foods, except orange juice, fulfilled pre-set acceptability criteria. Fiber enrichment did not change overall acceptability (p > 0.05) of the bread and pasta, but reduced overall acceptability (p < 0.05) of the muffin, orange juice, and breakfast bar. In all fiber-enriched products, flavor was the attribute most highly correlated with overall acceptability (p < 0.05). The lupin kernel fiber used in this study therefore appears to have potential as a 'nonintrusive' ingredient in some processed cereal-based foods. For other applications, fiber modification appears worthy of investigation to accomplish 'nonintrusive' fiber enrichment.     

In Vitro Binding of Vitamin B-6 by Selected Polysaccharides, Lignin, and Wheat Bran

Previous research has suggested that dietary fiber can reduce the bioavailability of certain micronutrients by ionic binding or physical entrapment. In this study, the ability of eight purified polysaccharides, lignin, and wheat bran to bind B-6 vitamers was examined in vitro using equilibrium dialysis under physiological conditions. The polysaccharides used were cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, methyl cellulose, citrus pectin, xanthan gum, sodium alginate, and gum arabic. No significant binding was detected when pectin was dialyzed to equilibrium at, 0.5, 0.75, and 1% levels in the presence of 0.1 or 0.1 mM pyridoxine, pyridoxamine, or pyridoxal. When 1% wheat bran, lignin, and the test polysaccharides were incubated overnight with 0.1 mM pyridoxine prior to dialysis, to allow for any slow binding process to occur, no in vitro binding of pyridoxine by any of the test materials could be observed on equilibrium dialysis. These results are consistent with findings of in vivo experiments which showed that cellulose, pectin, and bran did not significantly decrease the bioavailability of vitamin B-6 when fed to the rat and/or the chick.     

不同粒径对青稞麸皮结构与功能特性及冲调稳定性的影响

青稞麸皮是膳食纤维的丰富来源,然而其口感粗糙,目前在食品工业中的应用不足10％.超细研磨技术是一种能有效提升食品原料利用价值的新兴技术.本研究采用新型的气流冲击磨技术对青稞麸皮进行处理,得到了4组平均粒径不同的青稞麸皮,分别是粗青稞麸皮(coarse highland barley bran,CHB)、中青稞麸皮(me...     

Fiber Constituents and Fibrous Food Residue Effects on the In Vitro Enzymatic Digestion of Protein

In vitro digestibility of casein was significantly (P < 0.05) reduced as the fiber weight-to-protein weight ratio increased from 0.0:1.0 to 1.0:1.0 for isolated fiber constituents and fibrous food residues. For casein digestibility in the presence of fiber constituents, the reduction ranked in the following order: karaya gum > xylan > pectin > lignin > holocellulose. The order of reduction by fibrous food residues ranked as follows: kernel corn > blackeye pea > broccoli > brown rice > wheat bran. Gel filtration profiles of casein hydrolysates were generally not affected by the fiber constituents whereas significant alterations to greater molecular weight peptides occurred in the presence of food residues. The data supported the interaction of dietary fiber components by interference of the enzyme-substrate complex formation in proteolytic digestion.     

In-Vitro Studies on Functional Properties of Selected Natural Dietary Fibers

In-vitro experiments were conducted to provide predictive indices for the hypoglycemic effect of ashgourd, radish, pea peel, and cardamom peel fibers and its action of particle size and pH (related to human physiology) on the major functional properties. Ashgourd and radish fibers demonstrated significantly (p ≤ 0.05) higher water binding capacity and swelling capacity in stomach pH, i.e., 1.8; whereas pea peel and cardamom peel fibers exhibited higher hydration capacity at duodenal pH, i.e., 8.7. Ashgourd fiber (30 mesh) showed higher glucose adsorption capacity (452.1 μm/g) and exhibited maximum retarding effect on the flow of glucose across the dialysis bag for 12 h in comparison with other fiber sources. The 30 mesh (250–380 μm) and 60 mesh (150–230 μm) fiber particles showed better hydration properties as well as hypoglycemic effect as compared to 100 mesh (40–110 μm) particles. These fibers showed an excellent performance in relation to functional properties and hypoglycemic effect thus can be incorporated as low calorie bulk ingredient in high fiber foods to reduce calorie level and to help in controlling blood glucose concentration.     

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.     

Hydrolytic Stability and Changes in E Vitamers and Oryzanol of Extruded Rice Bran During Storage

Rice bran was extruded at 110, 120, 130, and 140°C with post extrusion holding times of 0, 3, and 6 min and stored at ambient temperatures for 1 yr. Holding time had no effect (p>0.05) on hydrolytic stability whereas 110°C was slightly less effective in maintaining hydrolytic stability. Increased holding times reduced (p<0.05) total vitamin E content. Oryzanol concentration was lower (p<0.05) only after 6 min holding time. Oryzanol was relatively more stable to extrusion temperatures than vitamin E. The highest retentions of total vitamin E and oryzanol were found in raw rice bran during storage. Increased extrusion temperatures reduced the retention of vitamin E and oryzanol during storage.     

Nutritional potential and functional properties of sweet and bitter lupin seed protein isolates

Protein isolates were prepared from both sweet and bitter lupin seed flours by two different methods, i.e. by alkaline water extraction/isoelectric precipitation (P1) and by micellisation (MI), and studied with regard to nutritional quality and functional properties. Protein solubility of both lupin seed flours was increased as sodium chloride concentration increased up to 1.0 M, then decreased. The minimum protein solubility of bitter lupin seed flour was quite sharp at pH 4.5, while it exhibited a broad pH range of 4.3–4.9 for sweet lupin seed flour. No significant (P<0.05) differences were found between any isolates in their dry matter, fiber, lipids and moisture contents. Isolates-PI from both sources had significantly (P<0.05) higher crude protein and ash contents than their isolates-MI. Bitter and sweet isolates-PI had lower values of total essential amino acids and higher values of tyrosine, phenylalanine, threonine, tryptophan and valine than isolates-MI. There was no significant (P>0.05) difference between bitter isolates in their alkaloid contents, while both sweet lupin isolates were free of total alkaloids. Bitter lupin isolate-PI had significantly (P<0.05) lower tannins, but sweet lupin isolate-MI had a significantly (P<0.05) higher phytic acid content than other isolates. Isolates-MI from both sources had higher chemical scores than their isolates-PI. The first and second limiting amino acids were total sulfur amino acids and valine, respectively, for all types of isolates. Sweet lupin isolate-MI had a higher essential amino acid index and protein efficiency ratio than other isolates. The protein solubility index, fat absorption and emulsification capacities of both isolates-MI were significantly (P<0.05) higher than their isolates-PI. Both sweet lupin isolates had significantly (P<0.05) higher water absorption capacity than bitter lupin isolates. Sweet lupin isolate-MI had significantly (P<0.05) higher foam capacity and foam stability than other lupin isolates.     

Changes in the content and composition of vitamin E in damp barley stored in airtight bins

The effect of airtight storage on the content and composition of vitamin E was studied in damp barley at 20 and 28% moisture. Airtight storage with an external supply of carbon dioxide was compared with conventional airtight storage with or without an expansion sack. In two additional models, the grain was also treated with 1% ammonia (NH3). The tocopherols and tocotrienols in the grain were analysed using high pressure liquid chromatography with fluorescence detection. The changes in vitamin E during airtight storage were determined by the moisture content of the barley. In barley at 20% moisture, the vitamin E content increased until mid-April and after 10 months the final levels were similar to those at harvest (55–65 mg kg^?1) except in the bin treated wih ammonia. In barley at 28% moisture, vitamin E breakdown processes prevailed from the beginning of airtight storage and led to an unsatisfactory level of this vitamin in the grain. In barley, α-tocotrienol was clearly the dominating isomer. The relative distribution of the isomers in barley at 20% moisture was stable during the airtight storage. For 28% moisture barley in most of the experimental models, the fraction of tocopherol isomers increased at the cost of the tocotrienols. It was concluded that the higher moisture content and a lower pH apparently favoured saturation of the side chains of the trienols. Treatment of barley with 1% ammonia gas resulted in a general decrease in the total vitamin E content and a simultaneous increase in the relative fraction of α-tocotrienol. Therefore, α-tocotrienol appeared to be more resistant to ammonia treatment than are the other isomers. For barley at 20% moisture content, the type of silo arrangement had hardly any effect on the vitamin E concentration or on the proportions of the isomers. For the barley at 28% moisture content, an external supply of CO₂ appeared to have a preservative effect on vitamin E content.     

Effect of Hard Red Spring Wheat Bran on the Bioavailability of Lipid-Soluble Vitamins and Growth of Rats Fed for 56 Days

Semipurified diets containing either 0, 5 or 20% wheat bran were fed ad libitum to male Sprague-Dawley rats. Significant increases in weights (P < 0.05) were found for the stomach, 32.6 ± 8.7%, and for the large intestine, 14.5 ± 4.8%, in rats fed 20% wheat bran compared to the control rats fed 0% wheat bran. Wheat bran consumption had no effect on plasma vitamin E or plasma vitamin A levels after 56 days of feeding; however, plasma vitamin A and vitamin E levels were shown to decline after 6 weeks and 5 weeks respectively, on the wheat bran diets. These studies suggest that some metabolic modifications induced by dietary wheat bran undergo reversible adaptations that are time dependent.     

The effect of different grain diets on fecal shedding of Escherichia coli O157:H7 by steers

Three groups of six yearling steers (three rumen fistulated plus three nonfistulated) fed one of three different grain diets (85% cracked corn, 15% whole cottonseed and 70% barley, or 85% barley) were inoculated with 10(10) CFU of Escherichia coli O157:H7 strain 3081, and the presence of the inoculated strain was followed in the rumen fluid and feces for a 10-week period. E. coli O157:H7 was rapidly eliminated from the rumen of the animals on all three diets but persisted in the feces of some animals up to 67 days after inoculation, suggesting that the bovine hindgut is the site of E. coli O157:H7 persistence. A significant difference existed in the levels of E. coli O157:H7 shed by the animals among diets on days 5, 7, 49, and 63 after inoculation (P < 0.05). No significant difference was found between the levels shed among diets on days 9 through 42 and on day 67 (P > 0.05). The number of animals that were culture positive for E. coli O157:H7 strain 3081 during the 10-week period was significantly higher for the barley fed group (72 of 114 samplings) as opposed to the corn fed group (44 of 114 samplings) (P < 0.005) and the cottonseed and barley fed group (57 of 114 samplings) (P < 0.05). The fecal pH of the animals fed the corn diet was significantly lower (P < 0.05) than the fecal pH of the animals fed the cottonseed and barley and barley diets, likely resulting in a less suitable environment for E. coli O157:H7 in the hindgut of the corn fed animals. E. coli O157:H7 strain 3081 was present in 3 of 30 (corn, 1 of 10; cottonseed, 1 of 10; barley, 1 of 10) animal drinking water samples, 3 of 30 (corn, 1 of 10; cottonseed, 0 of 10; barley, 2 of 10) water trough biofilm swabs, 5 of 30 (corn, 0 of 10; cottonseed, 2 of 10; barley, 3 of 10) feed samples, and 30 of 30 manure samples taken from the pens during the entire experimental period. Mouth swabs of the steers were also culture positive for E. coli O157:H7 strain 3081 in 30 of 180 samples (corn, 7 of 60; cottonseed, 4 of 60; barley, 19 of 60) taken during the 10-week period. Minimizing environmental dissemination of E. coli O157:H7 in conjunction with diet modification may reduce numbers of E. coli O157:H7-positive cattle.