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.     

桦褐孔菌纯化多糖体外降血糖活性研究

采用水提醇沉法得到桦褐孔菌发酵粗多糖,将粗多糖过DEAE-52纤维素柱分离纯化得到两种多糖(EIOP1、EIOP2),本文以α-葡萄糖苷酶抑制活性、正常HepG2细胞及胰岛素抵抗HepG2细胞的单位细胞葡萄糖消耗量为主要指标,探究桦褐孔菌两种纯化多糖不同浓度(10、20、40、80、160和320 μg/mL)的降血糖活性,其中α-葡萄糖苷酶抑制活性以阿卡波糖作为阳性对照,葡萄糖消耗实验以二甲双胍作为阳性对照。结果表明,EIOP1、EIOP2的α-葡萄糖苷酶抑制活性均高于阳性对照组阿卡波糖与粗多糖,IC₅₀值分别为39.18、29.87 μg/mL。EIOP1在浓度为80 μg/mL时,对HepG2细胞的葡萄糖消耗量极显著高于对照组,促进效果最好,比对照组提高了30.62%(P<0.01);EIOP2在浓度在40 μg/mL时,葡萄糖消耗量极显著高于对照组,比对照提高了75.99%(P<0.01);对胰岛素抵抗HepG2细胞的葡萄糖消耗实验发现EIOP1在浓度为40 μg/mL时,促进效果最好,比胰岛素抵抗组提高了30.00%,EIOP2在浓度为80 μg/mL时,促进效果最好,比胰岛素抵抗组提高了90.49%,高于Met组(P<0.01)。因此,桦褐孔菌纯化多糖对正常HepG2细胞和胰岛素抵抗HepG2细胞的葡萄糖消耗均具有促进作用,对α-葡萄糖苷酶的抑制活性显著高于粗多糖。     

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.     

榛子肽的体外抗氧化稳定性分析

利用中性蛋白酶制备榛子肽（<3 ku）,探讨环境因素对榛子肽抗氧化活性的影响,旨在为榛子肽的生产、贮藏和应用提供参考依据。随温度的升高,榛子肽的抗氧化活性显著降低（P<0.05）,在100 ℃处理3 h时,DPPH•、•OH清除能力活性维持率分别为83.61%、76.55%;pH值为6~8时榛子肽的活性可处于较高水平;当NaCl质量浓度在10 g/100 mL时,活性维持率分别为106.33%和100.25%;蔗糖浓度在2~10 g/100 mL的范围内活性维持率达到92%以上;葡萄糖质量浓度为10 g/100 mL时,活性维持率分别达到102.88%和103.39%;柠檬酸质量浓度为0.20 g/100 mL时,维持率分别为89.76%、102.64%;防腐剂在0.20 g/100 mL质量浓度,榛子肽活性能维持原有活性的80%以上;反复融冻10次,榛子肽的活性维持率分别为95.86%、95.15%;榛子肽在K+、Ca2+离子环境中的活性维持率较高;榛子肽经胃蛋白酶处理后的活性高于胃-胰蛋白酶处理。综合分析,为保持榛子肽较好的抗氧化活性,应避免长时间高温、强酸强碱及Cu2+、Zn2+离子接触,可添加适宜浓度NaCl、蔗糖、葡萄糖、柠檬酸、防腐剂,可冻融,对胃、胰蛋白酶具有耐受性。     

山药多糖的体外抗氧化活性

为探究山药多糖能否抑制低密度脂蛋白（low density lipoprotein,LDL）氧化,本实验提取了山药（Dioscorea opposita）多糖并除杂,分析了多糖的成分及体外抗氧化活性,对多糖能否抑制LDL氧化进行了初步探讨。结果表明,山药多糖的总糖质量分数为（65.79±1.03）%,蛋白质量分数为（5.89±0.43）%,灰分质量分数为（5.51±0.14）%,糖醛酸质量分数为（10.81±1.14）%;4 个主要多糖组分的分子质量分别为933 742、148 878、39 233、17 318 Da;对1,1-二苯基-2-三硝基苯肼自由基、超氧化物自由基和羟自由基清除率的半抑制质量浓度分别为1.06、1.06 mg/mL和0.98 mg/mL;可有效减缓共轭二烯的形成,1.0 μg/mL山药多糖对硫代巴比妥酸反应物的抑制率为CuSO4组的16.28%（P＞0.05）;但对LDL糖化的抑制作用不大。本研究可为了解山药多糖对LDL氧化的抑制作用提供参考。     

尿酸酶自组装空心纳米微球体外稳定性

制备载尿酸酶(Uricase,UOX)聚乙二醇-透明质酸(Hyaluronic acid-graft-poly(ethylene glycol),HA-g-PEG)/羟丙基-β-环糊精(Hydroxypropyl-beta-cyclodextrin,HPCD)自组装空心纳米微球(HA-g-PEG/HPCD self-assembly hollow spheres encapsulated uricase,UHPHD),并研究其体外稳定性。制备UHPHD,并测定其包封率、粒径及Zeta电位。再分别从最适温度、最适pH、热稳定性、贮存稳定性、酸碱稳定性和抗胰蛋白酶水解能力初步考察游离UOX和UHPHD的差异。结果:UHPHD的包封率为(62.17±2.94)%,粒径和Zeta电位分别为(299.60±13.05)nm和(-45.10±2.75)mV。UHPHD和UOX最适温度均为40℃,最适pH均为8.5。体外稳定性结果显示,UHPHD的体外稳定性明显高于UOX。     

In Vitro and In Vivo Metabolism of the Radiolytic Compound 2-Dodecylcyclobutanone

ABSTRACT: Our knowledge about the metabolism of alkylcyclobutanones (2-ACBs) is limited, and the lack of literature on the metabolism of 2-ACBs causes consumers to doubt the safety of irradiated foods. The objectives of this study were to evaluate the metabolism of 2-dodecylcyclobutanone (2-DCB) and identify any possible metabolite. The 2-DCB was mixed with rat S9 (postmitochondrial supernatant fraction) and β-nicotinamide adenine dinucleotide phosphate (NADPH) in phosphate buffer (pH 7.4) and incubated for 2 h at 37 °C. Then, the incubation mixture was mixed with sodium sulfate and extracted with n-hexane by using a Soxhlet apparatus. The hexane extract was concentrated under nitrogen and injected into the gas chromatography-mass spectrometry (GC-MS) machine running in selective ion monitoring mode (SIM) to measure 2-DCB concentration. The hexane extract from the in vitro and in vivo studies was also derivatized with a silylation reagent and injected into a GC-MS running in full scan mode. The average percentage of 2-DCB recovered from the test incubations was 23%, compared with 50% from the controls. The GC-MS chromatograms of the derivatized samples showed a unique peak in the in vitro test incubations and in the hexane extract of the rat feces that were given 2-DCB. This peak was later identified as 2-doecylcyclobutanol.     

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.     

Antiangiogenetic Effects of 4 Varieties of Grapes In Vitro

Abstract: The purpose of this study was to investigate the inhibitory effects of grapes on the human umbilical vein endothelial (HUVE) cells’ capillary tube formation and matrix metalloproteinase-2 (MMP-2) expression secreted into the medium. Four different grape varieties (Concord, Niagara, Chardonnay, and Pinot Noir) were extracted using 80% acetone and the extracts were stored at −80 °C. The total amount of phenolics and flavonoids for each of the 4 grape varieties were determined by spectrophotometry. Grape extracts were co-cultured with HUVE cells on Matrigel and inhibitory effects on tube formation were observed under a microscope. The inhibitory effects of grape extracts on MMP-2 expression were examined by zymogram. All 4 grape varieties inhibited the tube formation of HUVE cells in a dose-dependent manner on Matrigel. Except for Chardonnay, the other 3 grape varieties completely inhibited secretion of MMP-2 at 20 mg/mL. There was a significant positive relationship between the total phenolics and flavonoids and antiangiogenetic activities. The grapes tested have the potential to inhibit angiogenesis mainly by their phenolics and flavonoids contents, which partly contribute to their cancer chemopreventive efficacy.     

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.     

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.