In Vitro Binding of Vitamin E to Selected Dietary Fiber Sources

An in vitro method was used to assess interaction between whole fiber (WF) sources and vitamin E under simulated physiological conditions (pH 2, pH 7, pH 2–7; bile salt 5–15 mM; 37°C). Dose-response and binding characteristics (via Scatchard analysis) were examined. Binding of vitamin E by lupin and gum were higher (p≤0.05) at pH 2 and pH 7 than at the sequential treatment. Oat bran, treated at pH 7 or sequentially, showed increased (p≤0.05) binding of vitamin E as fiber level increased (25 - 100 mg). Scatchard plots revealed two specific noninteracting binding sites for sugarbeet and barley bran. Affinities (K_d) and capacities (n) were compared among fibers. Affinities for vitamin E were: sugarbeet>oat>lupin>barley>gum. Capacities were: barley > gum > lupin > sugarbeet > oat. Vitamin E binding to DF is complex, multifactorial, and not due to a single mechanism.     

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.     

In Vitro Antioxidant Activities of Polyphenols Purified from Four Plant Species Used in Rice Beer Preparation in Assam India

The purified phenolic extracts of Artocarpus heterophyllus, Oldenlandia corymbosa, Cyclosorus extensa, and Alpinia malaccensis were tested for the presence of various polyphenols and antioxidant activities. The polyphenols were extracted with ethanol and purified by stepwise dialysis and column elution. High-performance liquid chromatography was performed to detect and quantitate the polyphenols and 10 different in vitro methodologies were used to measure antioxidant properties. Quercetin, ferulic acid, and salicylic acid were present in all the species. Chlorogenic and p-coumaric acid in A. heterophyllus; p-coumaric acid, caffeic acid, naringin, catechol, and resorcinol in C. extensa; chlorogenic, caffeic, and quinic acid in O. corymbosa and naringin, quinic acid and catechol in A. malaccensis were detected with varied concentrations. The 2-deoxyribose, 1,1-diphenyl-2-picryl-hydrazyl and 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) assays exhibited high radical scavenging activities and they were also able to combat ?OH radicals and H₂O₂ to an extent of 25.53 and 71.23% respectively. Superoxide anions and nitric oxide radicals were scavenged up to 63.85 and 56.24%, respectively, and the extracts exhibited ferric ions chelation and ferrous ions reduction capacity. A reduction in the level of lipid peroxidation was also observed. All four species were found to be potent sources of polyphenols having antioxidative property. The results fully justified the use of these plants in the beer making process of Assam, India.     

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 Inoculum Enriched with Particle-Associated Microorganisms for Determining Rates of Fiber Digestion and Protein Degradation

In trial 1, rates of neutral detergent fiber digestion were measured on alfalfa hay with conventional inoculum prepared with strained ruminal fluid or inoculum also enriched with particle-associated microorganisms. Microorganisms from particles were obtained by washing the particle residue four times with nutrient-buffer. During the first 24 h, rates of neutral detergent fiber digestion from the enriched inoculum were approximately doubled. However, by 48 h differences in extent of neutral detergent fiber digestion were small. With the enriched inoculum but not the conventional inoculum, there was a linear increase of rate of neutral detergent fiber digestion with graded application of a mixture containing potassium carbonate, which enhanced field drying of hay. In trial 2, two additional inocula were prepared from whole contents of rumen that were either blended or had been chilled at 4°C. Digestion of neutral detergent fiber was not increased by chilling, and blending tended to lower digestion. In trial 3, seven inocula were evaluated in a protein degradation study. Three inocula enriched with particle-associated organisms yielded degradation rates of casein that were more than twice those with the conventional inoculum (.17/h versus .39/h). Inocula prepared from blended whole contents of rumen (with or without chilling) or from addition of Tween 80 before chilling did not increase rates of protein degradation. Inoculum enriched with particle-associated organisms can be used routinely to obtain improved estimates of in vitro rates of fiber digestion and protein degradation.     

Effect of Shredding Alfalfa Stems on Fiber Digestion Determined by In Vitro Procedures and Scanning Electron Microscopy

Alfalfa stems were shredded using a rotary macerator, were ammoniated, or were left untreated (control). Shredding increased extent of NDF digestion over ammoniation and control at all times from 12 to 72 h of in vitro incubation. Shredding also increased rate of disappearance of potentially digestible NDF (.032 h⁻¹ for control, .045 h⁻¹ for ammoniated, and .089 h⁻¹ for shredded). Ammoniation increased extent of NDF digestion after 36 h. Computed time required for 95% digestion of potentially digestible NDF was 94 h for control, 66 h for ammoniated and 34 h for shredded stems. Scanning electron microscopy revealed that the most prominent effect of shredding was separation of lignified and unlignified cells. Shredding split stems into a number of fragments and damaged the external cuticular waxy layer and structural integrity. Ammoniation caused cracks in lignified vascular tissue. During in vitro incubations, shredded and ammoniated cell walls were heavily colonized by bacteria by 6 h. After 24 and 48 h, large masses of bacteria were still attached to the surface of pith and lignified vascular cell walls of shredded and ammoniated stems but not control stems. Lignified vascular tissue of control stems was not degraded and structural integrity was maintained.     

Antioxidant Properties of Carotenoids In Vitro and In Vivo

Abstract

Carotenoids are a class of natural pigments familiar to all through the orange–red to yellow colors of many fruits, vegetables, and flowers, as well as for the provitamin A activity that some of them possess. A body of scientific evidence suggests that carotenoids may scavenge and deactivate free radicals, acting thereby as antioxidants both in food systems (in vitro) and in the human organism (in vivo). Overall, epidemiological evidence links higher carotenoid intakes and tissue concentrations with reduced cancer and cardiovascular disease risk. However, research has also shown that the antioxidant activity of carotenoids may shift to a prooxidant character depending mainly on the biological environment in which they act. A summary of the antioxidant potential of natural carotenoids both in oil model systems and in vivo is presented in this article.     

Antioxidant Properties of Carotenoids In Vitro and In Vivo

Carotenoids are a class of natural pigments familiar to all through the orange-red to yellow colors of many fruits, vegetables, and flowers, as well as for the provitamin A activity that some of them possess. A body of scientific evidence suggests that carotenoids may scavenge and deactivate free radicals, acting thereby as antioxidants both in food systems (in vitro) and in the human organism (in vivo). Overall, epidemiological evidence links higher carotenoid intakes and tissue concentrations with reduced cancer and cardiovascular disease risk. However, research has also shown that the antioxidant activity of carotenoids may shift to a prooxidant character depending mainly on the biological environment in which they act. A summary of the antioxidant potential of natural carotenoids both in oil model systems and in vivo is presented in this article.     

Lignin and Fiber Compositional Changes in Forages Over a Growing Season and Their Effects on In Vitro Digestibility

The composition of lignin and fiber was investigated in three forages, alfalfa (Medicago sativa L.), tall fescue (Festuca arundinacea Schreb.), and orchardgrass (Dactylis glomerata L.) hays, and the vegetative parts of corn (Zea mays) and wheat (Triticum aestivum L.) plants collected over the 1982 growing season to determine how lignin in different plants changes with plant growth and how this relates to changes in fiber and digestibility measures. The composition of lignin (by nitrobenzene oxidation) varied with the plant, harvesting frequency, and maturity, although changes were often more pronounced early in the growing season. Fiber composition and in vitro digestibility varied, but variability was spread over the entire growing season. Coefficients of determination between lignin components and fiber or digestibility measurements were highly forage dependent. The best predictor (among lignin components) of NDF or ADF or lignin content was p-hydroxybenzaldehyde for alfalfa, a mixture (acetovanillone and 4-allyl-2,6-dimethoxyphenol) for corn plant and orchardgrass, and syringic acid for tall fescue and wheat plant. Similarly, the best predictor of digestibility by a lignin component was the mixed component for alfalfa and orchardgrass and syringic acid for the others.     

Nutrient Uptake of Miscanthus In Vitro Cultures

Abstract

The large biomass production and the low input of fertilizer needed make Miscanthus an interesting potential non-food crop with broad applications, e.g., as fuel and energy, thatching, as fiber for production in the paper and car industry as well as ethanol production.

Axillary buds of Miscanthus × giganteus were placed on a shoot inducing nutrient solution (modified Murashige and Skoog, 1962) basic medium supplemented with 0.3 mg l^?1 6-Benzylaminopurin. After 40 days of culturing the axillary buds, three times more shoots could be harvested. The nutrient content (N, P, K, Ca, Mg) was determined several times during the culturing. The results showed that after 35 days, nitrogen and phosphate were almost completely taken up and thereafter no shoot growth was observed.

After the shoot propagation the plants were transferred into a nutrient solution for root formation and could be potted in soil, after about 14 days.     

Effects of Nutrient Additives and Sodium Hydroxide on Ensiling Characteristics and In Vitro Fiber Digestion Kinetics of Dairy Cattle Waste-Energy Feedstuff Mixtures

Dairy waste fiber was mixed in ratio 1:1 (dry matter basis) with ground alfalfa hay, chopped cornstalks, chopped whole corn plant, or ground corn. Prior to ensiling, mixtures received either no additive, dry cane molasses at 5% of dry matter, urea at 1% of dry matter, dry cane molasses at 5% plus urea at 1% of dry matter, sodium hydroxide at 3.3% of dry matter, or sodium hydroxide at 3.3% plus urea at 1% of dry matter. Lactate concentration of silages increased progressively in those receiving alkali, urea, or molasses. Sodium hydroxide treatment tended to increase unavailable nitrogen of silages. Molasses increased a) digestion rate of acid detergent fiber in alfalfa: dairy waste fiber, and b) digestion coefficients of corn silage: and corn:dairy waste fiber silages. Urea additions resulted in less digestion of stalklage:dairy waste fiber. Addition of soluble nitrogen and energy together often improved digestion over addition of either one alone. Sodium hydroxide was effective in increasing a) digestion of certain fiber fractions of all silages except corn silage: dairy waste fiber and b) digestion rate of corn silage:dairy waste fiber hemicellulose. Addition of urea to alkali-treated corn silage:dairy waste fiber increased digestion of neutral detergent fiber and hemicellulose beyond that of alkali-treated mixtures alone.     

类胡萝卜素膳食补充剂

类胡萝卜素膳食补充剂是一类特定的食品,被期望有良好的市场前景.在制造和消费者类产品时,有许多需要澄清的概念,有些是技术问题,有些是法律法规、有些是市场问题.本文综述了欧共体国家和美国的类胡萝卜素膳食补充剂的产品、市场、相关法规和保健功能研究的发展现状.     

米糖膳食纤维对胆酸钠吸附作用的研究

以酶法和化学法相结合制备出理化性能良好的脱脂米糠不溶性膳食纤维和脱脂米糠可溶性半纤维素B两种膳食纤维,在体外模拟条件下分别采用不同的分析方法测定它们对胆酸钠的吸附作用,发现两对胆酸钠都有显的吸附作用,吸附量分别为0．036－0．042g/g和0.013g/g,并由此就米糠膳食纤维降胆固醇作用的可能机理进行了探讨。     

In Vivo and In Vitro Assessment of Antinutritional Factors in Peanut and Soy

Raw and heat processed peanut flours were found to contain higher in vitro trypsin inhibitor activity and lectin content than similarly processed soy flour. When fed to weanling rats at a level of 10% protein, the response pattern in food consumption, growth, liver function, and serum chemistries was not consistent among or between the groups. It is concluded that the levels of antinutritional factors in legumes do not correlate with their overall biological impact in feeding studies with the rat.     

Binding of 14C-Labeled Food Mutagens (IQ, MeIQ, MeIQx) by Dietary Fiber In Vitro

Binding of three mutagens, known to occur in fried or broiled foods, by thirteen different types of dietary fiber was investigated in vitro. Nonspecific binding by other food polymers was minimized by using protease and amylase treatment. Water-insoluble fiber components were responsible for most of the binding capacity. Generally, a slightly larger proportion of 2-amino-3,4-dimethylimidazo [4,5-f]quinoline (MeIQ) than of 2-amino-3-methylimidazo [4,5-f]quinoline (IQ) and 2-amino-3,8-dimethylimidazo] -4,5-f]quinoxaline (MeIQx) was bound. There was a significant correlation between Klason lignin content and binding of mutagens. Optimum pH for binding was between 4 and 6. Dietary fiber from sorghum had the highest binding capacity, which could be due to the presence of a large Klason lignin fraction.     

组织培养技术在葡萄无核育种上的应用

葡萄组织培养技术，特别是胚、胚珠培养技术在无核葡萄育种研究中发展迅速。利用无核葡萄品种作母本，特别是利用假单性结实的无核葡萄品种作母本，用无核品种涂父本进行杂交，合子胚还未败育时，采用胚珠培养技术可以得到杂种实生苗．这种杂种实生苗无垓比例较高，可以达到８２％，理论上可达１００％。选择合适的亲本，掌握无核葡萄胚珠败育时期，培养基激素的选择，以及如何促进胚的萌发，是正确利用这项技术的关键。     

Maillard Browning Effects on In Vitro Availability of Zinc

An in vitro dialysis procedure was employed to determine the effect of Maillard browning on apparent ⁶⁵Zn availability. In the presence of ⁶⁵ZnCl₂, the amino acids glycine, D-leucine, L-proline, L-lysine and L-glutamic acid were combined with D-glucose and autociaved (110°-120°C, 15 atm, 10 min) to produce high molecular weight ⁶⁵Zn binding compounds that were not bialyzable (6-8 KD). Nondialyzable bound zinc is considered to be unavailable; however, subjecting these compounds to simulated gastrointestinal digestive conditions released most of the unavailable ⁶⁵Zn. Dialysis of degerminated corn meal samples, which had been extrinsically labeled with ⁶⁵Zn, showed that toasting (220°C, 25 min) decreased the availability of ⁶⁵Zn. Simulated digestion released a portion of this unavailable ⁶⁵Zn.     

当前化纤业现状及江苏化纤业发展对策

近年来,随着世界经济的跌宕起伏,全球化纤行业的生产力布局发生了重大变化,市场竞争愈演愈烈。抓住世界化纤产业梯度转移的历史机遇,积极应对“入世”后面临的严峻挑战,运用创新思维整合行业资源,采用品牌战略优化产品结构,应用高新技术提升技术水平,这对促进江苏“化纤大省”发展成“业纤强省”意义重大。     

Effect of Myoinositol Phosphate Esters on In Vitro and In Vivo Digestion of Protein

Effects of phytate and its hydrolysis products (myo-inositol phophate esters) on protein digestion were investigated by in vitro and in vivo procedures. Tri-, tetra-, penta-, and hexa-phosphate ester fractions, isolated from phytate hydrolysates, inhibited pepsin digestion of casein and bovine serum albumin in vitro. The inhibition ranged from 0% for the mono- and diphosphate esters to 9–14% with the hexa-phosphate ester (phytate). The phosphate ester fractions did not significantly affect trypsin digestion of the proteins. In the in vivo study, rats were fed phytate and hydrolysates thereof (mixtures of the esters above) at levels of 1–3.5% of the diet. Under the conditions of this study, neither phytate nor its hydrolysates significantly affected protein utilization or weight gain in rats.