Distribution of vitamins A and E in blood and liver of rats depleted of vitamin A or vitamin E

Young Sprague-Dawley male rats (n=150) were fed a semipurified diet, either without vitamin A (VA), without vitamin E (VE) or supplemented with both vitamins A and E (control). At the end of weeks 0, 1, 3, 5, 6, 7, 8 and 9, groups of rats were anesthetized with methoxyflurane, and blood was collected by cardiac puncture until the rat was exsanguinated. The liver was excised. Whole blood (WB_ from each rat was fractionated into plasma (PLA), leukocytes (LEU), platelets (PLT) and erythrocytes (RBC). Each blood components was extracted with hepatane and livers were extracted with CHCl₃/CH₃OH (2∶1, v/v). The extracts were analyzed for VA and VE by high performance liquid chromatography. The relationship among blood components in the loss of VA was PLT=LEU>WB>PLA. The relationship among blood components in the loss of VE was PLA>RBC>WB>LEU-PLT. VA and VE levels in other blood components decreased precipitously between weeks 0 and 4 in the animals placed on deficient diets. These results and correlation analyses between vitamin contents of blood components and of livers indicate inadequacies for the use of certain blood components as monitors of lipid-soluble vitamin status in the rat.     

Cereal bars with soy protein and wheat germ, physicochemical characteristics and texture during the storage

Studies analyzing cereal bars have reported on consumer characteristics and preferences in sensory analyses and on their market growth, however little has been published on their physicochemical data and texture properties. Thus the objective of this research was to provide information about the storage of a cereal bar formulation with high protein and vitamin levels based on soy protein and wheat germ, packaged in 3 different films (A: PET/PEBD; B: PETmet/PEBD; C: PET/PEBD/AL/PEBD), during 6 months under environmental conditions of temperature (25 +/- 2 degrees C) and relative humidity (56%). The moisture content, water activity, pH and total acidity of the cereal bars were determined. The textural measurements accompanied during storage were breaking strength, hardness and cohesiveness. The cereal bars presented variations in water activity (Aw), moisture content and total acidity during storage. The moisture content of the bars tended to increase, which led to a significant (p = 0.05) influence on the texture characteristics of breaking strength and hardness, in the different packaging films tested. The increase in the values for breaking strength (A: 4756,5N; B: 5093,0N; C: 5575,6N) at 45 days of storage was attributed to a possible crystallization of the agglutinating syrup used for the bars. The textured soy protein used in the formulation could also have contributed to this fact due to its hygroscopic character, also interfering in the decrease in the cohesiveness measurements (deformation) with time. The effect of the different barrier properties of the packaging films tested was significant (p < 0.05) in the stability of the cereal bars during storage.     

Relationship between oxidative stability of vitamin E and production of fatty acids in oils during microwave heating

Effects of microwave heating on the oxidative stability ofd-tocopherols were studied in relation to the production of fatty acids in oils. During microwave heating, the stability of tocopherols decreased in the orderδ>β>γ>α. This order did not depend on the types of ethyl esters of fatty acids or oils present. But, the shorter the chainlength and the lower the degree of unsaturation of the fatty acid ethyl esters, the greater was the reduction in amount of individual tocopherols. A similar tendency was observed when tocopherol-stripped vegetable oils, with equimolar mixtures of tocopherols added, were treated under the same conditions. The reduction in tocopherols became greater with increasing levels of free fatty acids.     

Oxidative stability of low density lipoproteins and vitamin E levels increase in maternal blood during normal pregnancy

In 24 healthy pregnant women, parameters related to the oxidative stability of low density lipoproteins (LDL) were determined at three times during pregnancy and shortly after delivery. The fatty acid composition of plasma phospholipids (PL) and the plasma concentrations of vitamin E, vitamin A, and β-carotene were assessed in the same samples. Total triglyceride (TG), total cholesterol, LDL-cholesterol, and high density lipoprotein (HDL)-cholesterol concentrations were also determined. The length of the lag phase of isolated LDL challenged with Cu²⁺ ions significantly increased with the progression of pregnancy. The oxidation rate and the amount of conjugated dienes formed increased and reached a maximum at 29–37 wk of pregnancy. Total TG, cholesterol, and LDL-cholesterol reached a maximum in the third trimester of pregnancy. β-Carotene remained stable, vitamin A decreased, and vitamin E significantly increased throughout pregnancy. Vitamin E plasma concentration correlated positively with the length of the lag phase. The increased levels of vitamin E could contribute to the higher resistance of LDL toward oxidation with progressing gestation, measured by the prolonged lag phase. Furthermore, vitamin E plasma levels correlated positively with TG concentration but not with LDL-cholesterol. The level of polyunsaturated fatty acids in PL decreased with the progression of pregnancy. No correlation was found between the fatty acid composition of plasma PL, nor with the cholesterol concentration, and the parameters studied related to the oxidative stability of LDL. The major finding of this study is the increased oxidative resistance of LDL with progressing gestation.     

分子蒸馏和脂肪酶催化水解菜籽油脱臭馏出物浓缩维生素E的优化研究

采用分子蒸馏耦合脂肪酶催化水解菜籽油脱臭馏出物,并用碱中和、水洗萃取以浓缩维生素E.着重考察了脂肪酶活力,添加的水量和反应时间对水解效果的影响.通过正交实验获得较好的水解工艺条件添加的水量/水解原料比15 mL/15 g,脂肪酶活/水解原料105 U/g,反应时间5 h,反应温度37℃,经后续处理后维生素E纯度达到17.3%,回收率85%.固定化酶可以重复利用多次.     

Gelatin and pregelatinized starch orally disintegrating films: Properties and stability of vitamin C

The administration of active compounds by the oral mucosa is an efficient method for the delivery of drugs and nutrients. This work aimed to develop and characterize orally disintegrating films (ODFs) based on starch and gelatin as carriers of vitamin C. The ODFs were produced using a casting technique by varying the concentrations of starch and gelatin (0, 20, 40, 60, 80, and 100 g of starch/100 g of polymer) and were characterized in relation to contact angle, opacity, surface pH, infrared spectroscopy, mechanical properties, morphology, and disintegration time (in vitro and in vivo). Additionally, the stability of vitamin C in the ODFs was evaluated by the incorporation of the dry extract of acerola (4 g/100 g of filmogenic solution). Generally, the ODFs presented hydrophilic characteristics with a neutral surface pH near the mouth, and films with higher starch concentrations showed greater rigidity. In vitro and in vivo tests indicated that ODFs may be classified as rapidly disintegrating. The ODFs produced with higher concentrations of starch showed a higher stability of the active compound, in addition to a shorter disintegration time. Starch‐ and gelatin‐based ODFs can be considered a new system for administering active ingredients via the oral mucosa. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44841.     

Solubilization of vitamin C in fish oil and synergistic effect with vitamin E in retarding oxidation

Antioxidative effects of ascorbic acid and δ-tocopherol on the oxidation of sardine oil stored at 30°C in the dark has been investigated. It was found from phase diagrams and peroxide values of fish oil/lecithin/water systems that the desirable levels of lecithin and water to solubilize ascorbic acid in the oil were 0.3% (w/w) and 0.1% (w/w), respectively. When ascorbic acid (0.02%) and δ-tocopherol (0.4%) were used together, the induction period of fish oil could be lengthened 22-fold, due to their synergism. They could inhibit the production of carbonyl and volatile compounds and oxidative polymerization.     

Nutritional and stability evaluation during storage of blends extruded with sorghum

Binary sorghum:soy (70:30) and ternary sorghum:corn:soy (30:40:30) blends using high and low tannin content dehulled sorghum were extruded. The effectiveness of heat treatment was determined by protein dispersion index (PDI) and ureasic activity (delta PH), indicating that proteins were denatured and antinutritional factors reduced. The nutritional evaluation supported the fact that samples were adequately treated, giving ternary blends true digestibility (TD) and biological values (BV) similar to milk casein. Blend stabilities, expressed as peroxide index (PI), revealed a low lipid oxidation rate during the first seven months, and were acceptable up to a year of storage. Extrudates with incorporated sorghum cover protein and energy demands of the growing infant, and provide a high nutritional value and long-life product.     

In vitro oxidation of vitamins C and E,cholesterol, and thiols in rat brain synaptosomes

Free radical-induced oxidation of vitamins C, E, sulfhydryl compounds, and cholesterol in brain synaptosomes from Fisher 344 rats was studied. The synaptosomes were incubated at 37°C with 2,2′-abobis-(2-amidinopropane) dihydrochloride (AAPH), which undergoes thermal decomposition to yield free radicals. After incubation, the synaptosomes were sedimented, saponified, and extracted with hexane to isolate tocopherol and cholesterol. Ascorbate and tocopherol were assayed by liquid chromatography, cholesterol by gas chromatography, and total sulfhydryls by spectrophotometry. Under thein vitro conditions used in this study, the approximate order for the ease of oxidation of the various compounds was: ascorbate ≫tocopherol>sulfhydryl compounds⋙cholesterol. However, tocopherol and sulfhydryl oxidation occurred even before all of the ascorbate had been consumed. Therefore, the fate of a specific antioxidant at a particular cellular location cannot be predicted with complete accuracy using thein vitro order for ease of oxidation shown here. Ascorbate may play a major role in protecting brain against oxidative damage because: (i) ascorbate concentration is high in brain, (ii) it can regenerate vitamin E from its radical oxidation product, and (iii) it is one of the first antioxidants to be consumed during oxidative reactions.     

重组干酪乳杆菌贮存期内质粒稳定性及活菌数的检测

目的检测产肠毒素性大肠杆菌(Enterotoxigenic E.coli,ETEC)基因重组干酪乳杆菌(Lactobacillus casei,L.casei)贮存过程中质粒的稳定性及活菌数的变化。方法将ETEC K88重组干酪乳杆菌(pLA-K88/L.casei)接种于MRS培养基,转种WPC培养基,收集菌液,置4、15、37℃贮存。通过抗生素MRS(+)和MRS(-)平板计数菌落数的方法及PCR法检测重组质粒在4℃贮存1、15、30、60、90和120 d的稳定性;Dot ELISA法检测菌液外源蛋白免疫学活性的变化;平板计数法检测4、15、37℃贮存1、2、3、7、15、30、60、90、120、210和240 d的活菌数。结果在4℃贮存120 d内,重组质粒稳定性良好,目的基因片段无缺失,外源蛋白活性稳定,乳清蛋白对工程菌的稳定性及外源蛋白的免疫原性均无影响;工程菌在4℃贮存效果最好,存活时间最长,第240 d活菌数仍保持在9×106cfu/ml以上,15和37℃贮存期仅为90和15 d。结论 ETEC基因重组干酪乳杆菌于4℃贮存条件下,质粒及外源基因表达稳定。     

Nutritional composition and vitamin C stability in stored camu-camu (Myrciaria dubia) pulp

Camu-camu (Myrciaria dubia), a native fruit of the Amazon region, is one of the richest sources of vitamin C (2.4 to 3.0 g/100 g in the pulp) found in Brazil. The purpose of this work was the physical-chemical characterization of some nutrients and the valuation of vitamin C stability in stored camu-camu pulp, produced by the Agronomic Institute of Paraná (IAPAR), Paraná State, Brazil. The vitamin C determination was made by titration with potassium iodate. The fruit produced in Paraná State, presented a lower content of vitamin C than the one native of the amazon region, possibly due to the different development conditions of the plant, and consequently of the fruit, as well as the climatic variation, the humidity and the characteristics of the soil. Regarding the vitamin C stability in stored (-18 degrees C) camu-camu pulp, a considerable decrease in its concentration until the 28th day was observed lost 23% (from 1.57 to 1.21 g/100 g), staying approximately the same until the end of the experiment. After 335 days of storage, the content found was of approximately 1.16 g/100 g of pulp, the ascorbic acid losses amounted to 26%. This content was still higher than the one found for most fruits that are good sources of this vitamin.     

Temperature stability of vitamin D2 and color changes during drying of UVB-treated mushrooms

The study investigates the effect of drying temperature on vitamin D₂ content and color changes of UVB-treated shiitake (Lentinula edodes), oyster (Pleurotus ostreatus), and white and brown button mushrooms (Agaricus bisporus). Fresh samples were UVB treated up to 1.5?J/cm² for 20?min at 25°C and either dried in a high precision dryer (temperatures: 40, 60, 80°C, specific humidity: 10?g/kg, air velocity: 0.6?m/s) or frozen at ?25°C, and then freeze-dried (pressure: 0.28?mbar). Vitamin D₂ content was not negatively affected by the increased temperatures of the drying air. The highest content of vitamin D₂ was detected in freeze-dried (171.84?µg/g) and hot-air dried shiitake at 60°C (169?µg/g), followed by oyster (121.96?µg/g), whereas the lowest amount was observed in brown button mushrooms at 40°C (34.65?µg/g). Although vitamin D₂ indicated a remarkable stability even at 80°C, the dried samples were characterized by intensive tissue darkening.     

Oxidative stability during storage of structured lipids produced from fish oil and caprylic acid

Structured lipids produced by enzymatic or chemical methods for different applications have been receiving considerable attention. The oxidative stability of a randomized structured lipid (RFO), produced by chemical interesterification from fish oil (FO) and tricaprylin, and a specific structured lipid (SFO), produced by enzymatic interesterification from the same oil and caprylic acid, was compared with the stability of FO. Oils were stored at 2°C for 11 wk followed by storage at 20°C for 6 wk. In addition, the antioxidative effect of adding the metal chelators EDTA or citric acid to SFO was investigated. FO contained the largest amount of PUFA and RFO the lowest. However, SFO had a higher PV initially and during storage at 2°C, whereas the PV of FO was highest during storage at 20°C. The level of volatile oxidation products was highest in SFO during the entire storage period, and off-flavors were more pronounced in SFO. The lower oxidative stability of SFO was probably related to the initially lower quality (regarding oxidation products), which is apparently a result of the long production procedure required. Addition of metal chelators did not reduce the oxidation of the SFO.     

Biokinetics of dietaryRRR-α-tocopherol in the male guinea pig at three dietary levels of vitamin C and two levels of vitamin E. Evidence that vitamin C does not “spare” vitamin Ein vivo

The net rates of uptake of “new” and loss of “old”2R,4′ R,8′ R-α-tocopherol (RRR-α-TOH, which is natural vitamin E) have been measured in the blood and in nine tissues of male guinea pigs over an eight week period by feeding diets containing deuterium-labelled α-tocopheryl acetate (d ₆-RRR-α-TOAc). There was an initial two week “lead-in” period during which 24 animals [the “high” vitamin E (HE) group] received diets containing 36 mg of unlabelled (d ₀)RRR-α-TOAc and 250 mg of ascorbic acid per kg diet, while another 24 animals [the “low” vitamin E (LE) group] received diets containing 5 mgd ₀-RRR-α-TOAc and 250 mg ascorbic acid per kg diet. The HE group was then tivided into three equal subgroups, which were fed diets containing 36 mgd ₆-RRR-α-TOAc and 5000 mg [the “high” vitamin C (HEHC) subgroup], 250 mg [the “normal” vitamin C (HENC) subgroup] and 50 mg [the “low” vitamin C (HELC) subgroup] ascorbic acid per kg diet. One animal from each group was sacrificed each week and the blood and tissues were analyzed ford ₀- andd ₆-RRR-α-TOH by gas chromatography-mass spectrometry. The LE group was similarly divided into three equal subgroups with animals receiving diets containing 5 mgd ₆-RRR-α-TOAc and 5,000 mg (LEHC), 250 mg (LENC) and 50 mg (LELC) ascorbic acid per kg diet with a similar protocol being followed for sacrifice and analyses. In the HE group the totald ₀-+d ₆-)RRR-α-TOH concentrations in blood and tissues remained essentially constant over the eight week experiment, whereas in the LE group the totalRRR-α-TOH concentrations declined noticeably (except in the brain, an organ with a particularly slow turnover of vitamin E). There were no significant differences in the concentrations of “old”d ₀-RRR-α-TOH nor in the concentrations of “new”d ₆-RRR-α-TOH found in any tissue at a particular time between the HEHC, HENC and HELC subgroups, nor between the LEHC, LENC and LELC subgroups. We conclude that the long-postulated “spring” action of vitamin C on vitamin E, which is well documentedin vitro, is of negligible importancein vivo in guinea pigs that are not oxidatively stressed in comparison with the normal metabolic processes which consume vitamin E (e.g., by oxidizing it irreversibly) or elminate it from the body. This is true both for guinea pigs with an adequate, well-maintained vitamin E status and for guinea pigs which are receiving insufficient vitamin E to maintain their body stores. The biokinetics of vitamin E uptake and loss in the HE guinea pigs are compared with analogous data for rats reported previously (Lipids 22, 163–172, 1987). For most guinea pig tissues the uptake of vitamin E under “steadystate” conditions was faster than for the comparable rat tissues. However, the brain was an exception with the turnover of vitamin E occurring at only one-third of the rate for the rat. NRCC Publication No. 30775.     

Lipid peroxidation during n−3 fatty acid and vitamin E supplementation in humans

The purpose of this study was to investigate in healthy humans the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake, alone or in combination with dL-α-tocopherol acetate (vitamin E) supplements on lipid peroxidation. Eightly men were randomly assigned in a double-blind fashion to take daily for 6 wk either menhaden oil (6.26 g, n−3 fatty acids) or olive oil supplements with either vitamin E (900 IU) or its placebo. Antioxidant vitamins, phospholipid composition, malondialdehyde (MDA), and lipid peroxides were measured in the plasma at baseline and week 6. At the same time, breath alkane output was measured. Plasma α-tocopherol concentration increased in those receiving vitamin E (P<0.0001). In those supplemented with n−3 fatty acids, EPA and DHA increased in plasma phospholipids (P<0.0001) and plasma MDA and lipid peroxides increased (P<0.001 and P<0.05, respectively). Breath alkane output did not change significantly and vitamin E intake did not prevent the increase in lipid peroxidation during menhaden oil supplementation. The results demonstrate that supplementing the diet with n−3 fatty acids resulted in an increase in lipid peroxidation, as measured by plasma MDA release and lipid peroxide products, which was not suppressed by vitamin E supplementation.     

Sparing effects of selenium and ascorbic acid on vitamin C and E in guinea pig tissues

Background

Selenium (Se), vitamin C and vitamin E function as antioxidants within the body. In this study, we investigated the effects of reduced dietary Se and L-ascorbic acid (AA) on vitamin C and α-tocopherol (AT) status in guinea pig tissues.

Methods

Male Hartley guinea pigs were orally dosed with a marginal amount of AA and fed a diet deficient (Se-D/MC), marginal (Se-M/MC) or normal (Se-N/MC) in Se. An additional diet group (Se-N/NC) was fed normal Se and dosed with a normal amount of AA. Guinea pigs were killed after 5 or 12 weeks on the experimental diets at 24 and 48 hours post AA dosing.

Results

Liver Se-dependent glutathione peroxidase activity was decreased (P < 0.05) in guinea pigs fed Se or AA restricted diets. Plasma total glutathione concentrations were unaffected (P > 0.05) by reduction in dietary Se or AA. All tissues examined showed a decrease (P < 0.05) in AA content in Se-N/MC compared to Se-N/NC guinea pigs. Kidney, testis, muscle and spleen showed a decreasing trend (P < 0.05) in AA content with decreasing Se in the diet. Dehydroascorbic acid concentrations were decreased (P < 0.05) in several tissues with reduction in dietary Se (heart and spleen) or AA (liver, heart, kidney, muscle and spleen). At week 12, combined dietary restriction of Se and AA decreased AT concentrations in most tissues. In addition, restriction of Se (liver, heart and spleen) and AA (liver, kidney and spleen) separately also reduced AT in tissues.

Conclusion

Together, these data demonstrate sparing effects of Se and AA on vitamin C and AT in guinea pig tissues.     

Enhancing storage stability of emulsions by binding detergents with soy protein isolate and its hydrolysates

Sodium dodecyl sulfate (SDS) is a frequently used anionic detergent, and proteins are among the widely used minor ingredients in cosmetic products. Proteins may enhance the detergent functions and protect human skin from irritation caused by detergents. Soy protein hydrolysates (SPH) were prepared by modifying soy protein (SP) with papain. Varying concentrations of SP or SPH were mixed with various concentrations of SDS at different pH values to determine: (i) molecular characteristics, degree of hydrolysis (DH), and surface hydrophobicity (S ₀) of SP and SPH; (ii) the effect of SDS concentrations on the S ₀ of SP; (iii) the storage stabilities of oil-in-water emulsions formed by SDS, SP, SPH, SP-SDS, and SPH-SDS; and (iv) the effect of protein concentration (0.01 to 1.5%), DH (1.2 to 12.5%), and pH (3.0, 5.0, 7.0, and 9.0) on storage stabilities of emulsions formed by SP-SDS or SPH-SDS. An increase in emulsion stability (ES) with increasing protein concentration was observed. The ES values of emulsions formed by SPH-SDS complexes were significantly higher than those formed by SP-SDS at pH 7.0 and 9.0. The ES of emulsions formed by the complexes were low at pH 5.0 and increased with increasing pH. At pH 3.0 the emulsions formed by SP-SDS at 1 to 1.5% protein concentration and by SPH-SDS at 1.5% protein concentration were very stable. The results indicate that at least one-half of SDS content can be replaced by SP or SPH while maintaining emulsion stability.     

Involvement of vitamin E and protein thiols in the inhibition of microsomal lipid peroxidation by glutathione

Iron-ascorbate stimulated lipid peroxidation in rat liver microsomes can be inhibited by glutathione (GSH). The role of protein thiols and vitamin E in this process was studied in liver microsomes isolated from rats fed diets either sufficient or deficient in vitamin E and incubated at 37°C unde 100% O₂. Lipid peroxidation was induced by adding 400 μM adenosine 5′-triphosphate, 2.5 to 20 μM FeCl₃, and 450 μM ascorbic acid. One mL of the incubation mixture was removed at defined intervals for the measurement of thiobarbituric acid reactive substances (TBARS), protein thiols and vitamin E. In vitamin E sufficient microsomes, the addition of GSH enhanced the lag time prior to the onset of maximal TBARS accumulation and inhibited the loss of vitamin E. Treatment of these microsomes with the protein thiol oxidant diamide resulted in a 56% loss of protein thiols, but did not significantly change vitamin E levels. However, diamide treatment abolished the GSH-mediated protection against TBARS formation and loss of vitamin E during ascorbate-induced peroxidation. Liver microsomes isolated from rats fed a vitamin E deficient diet contained 40-fold less vitamin E and generated levels of TBARS similar to vitamin E sufficient microsomes at a 4-fold lower concentration of iron. GSH did not affect the lag time prior to the onset of maximal TBARS formation in vitamin E deficient microsomes although total TBARS accumulation was inhibited. Similar to what was previously found in vitamin E sufficient microsomes [Palamanda and Kehrer, (1992)Arch. Biochem. Biophys. 293, 103–109], GSH prevented the loss of protein thiols in vitamin E deficient microsomes. However, GSH did not protect efficiently against the loss of residual vitamin E in deficient microsomes. These data provide support for the concept that GSH protects against microsomal lipid peroxidation by maintaining protein thiols, and consequently vitamin E, in the reduced state. The lack of protection in vitamin E deficient microsomes may be related to the inability of such low levels of vitamin E to inhibit peroxidation.     

Antioxidative properties of irradiated chitosan/vitamin C complex and their use as food additive for lipid storage

Improving the antioxidant activity of chitosan was achieved by decreasing their molecular weight by γ rays followed by incorporation with vitamin C to prepare chitosan/vitamin C (CSVC) complex in the range of nanoparticles. Transmittance electron microscopy of CSVC complex showed mean diameters ranged from 23.2 to 82 nm. The antioxidant activities of CSVC complexes were examined using scavenging effect on DPPH radicals and reducing power measurements. CSVC complexes have a synergistic effect on increasing the antioxidant properties rather than their individual effects. The effect of CSVC complexes on lipid peroxidation of meat during 21 days of refrigerated storage was investigated using thiobarbituric acid reactive substance (TBARS) assay. Treatment of meat with CSVC complex reduced lipid peroxidation about 75% after 7 days of storage as a result the decrease in TBARS values. The results demonstrate promising use of CSVC complex as antioxidants for lipid storage. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42105.