食物中维生素A、叶酸和维生素E分析方法研究进展

对食物中 3种重要的维生素 :维生素A、叶酸和维生素E的常用分析方法进行了综述。指出了不同分析方法的适用范围以及各自的优缺点。着重介绍了高效液相色谱法在此 3种维生素分析中的应用。并提出了分析方法的发展趋势是高效液相色谱法 (包括正相高效液相色谱法、反相高效液相色谱法和非水反相高效液相色谱法 )、高效液相 -质谱法、气相色谱 -质谱法和离子色谱-质谱法等方法。     

高效液相色谱法同时测定食用油中维生素A和E的方法

本文建立了高效液相色谱法同时测定食用油中维生素A和4种维生素E生育酚的方法。利用维生素A醋酸酯和维生素E生育酚分别在325nm和294nm的波长下的吸收特性。以液相色谱紫外检测器双波长的方式,考察研究处理方式并开发同时检测食用油中维生素A和E的方法。通过该方法结果表明：维生素A的精密度RSD为0.84%~1.39%,回收率范围在95.8%~104.4%;维生素E的各生育酚组分精密度RSD为2.01%~4.14%,回收率范围在96.2%~112%。本方法也可应用于测定不同食用油中维生素A和E且有效可靠。测得葵花籽油维生素A含量735.58±3.86 μg/100g,维生素E(α-TE)的含量为54.33±2.92 mg/100g;玉米油维生素A含量676.75±2.15 μg/100g,维生素E(α-TE)的含量为24.78±1.36 mg/100g。通过方法验证,确认液相色谱同时检测维生素A和E的方法用于食用油中有效可靠。     

Fatty acid and vitamin E composition of intramuscular fat in cattle reared in different production systems

The aim of this study was to evaluate the fatty acid composition of intramuscular fat and the vitamin E content of beef from different production systems. Four cattle production systems were used: cattle reared under intensive conditions and fed concentrate (INT1) from Spain, cattle raised at pasture and supplemented with concentrate (SUP1) from the United Kingdom, cattle raised at pasture and on corn silage (SUP2) from Germany and cattle reared under extensive conditions slaughtered at two and three years old (EXT2 and EXT3) from Uruguay. The highest proportion and content (mg per 100 g of muscle) of linoleic acid (C18:2n-6) and arachidonic acid (C20:4n-6) and the lowest saturated fatty acids (SFA) was found in INT1 beef. In contrast, beef reared under extensive conditions showed the highest proportion and content of linolenic acid (C18:3n-3), docosapentaenoic acid (DPA, C22:5n-3) and eicosapentaenoic acid (EPA, C20:5n-3), and SUP1 and SUP2 beef showed the highest level of palmitic acid (C16:0) and SFA. Beef from intensive system (INT1) had the lowest P/S (PUFA/SFA) ratio, whereas beef from extensive system (EXT2 and EXT3) had the lowest n-6/n-3 ratio. The results of the PCA (principal components analysis) of fatty acid composition showed that beef from intensive system (INT1) was clearly differentiated from the other meats and was located with the C18:2n-6 and C20:4n-6 and the n-6/n-3 ratio. EXT2 and EXT3 beef were located with C18:3n-3 and long chain fatty acids. Beef from extensive systems had the highest concentration of vitamin E (3.91 mg α-tocopherol/kg muscle).     

保健食用油一紫苏油研究进展

紫苏油作为一种优良的保健食用油,对其组成成分、理化性质和生理作用等作了综述,并对其开发前景进行了展望.     

维生素E微胶囊化研究

以变性淀粉为壁材、PEG400-单油酸为乳化剂，对维生素E微胶囊化的配方和工艺进行了研究。试验结果表明最佳条件为：维生素E、变性淀粉、PEG400-单油酸、海藻酸钠的比例为25：30：5：0．6，固形物含量30％，均质压力30MPa，均质温度60℃，喷雾进风温度185—195℃，进料温度60℃。     

Encapsulation of vitamin E in edible emulsions fabricated using a natural surfactant

Vitamin E is a fat-soluble vitamin widely used in pharmaceutical, supplement, food, and cosmetic preparations that must be encapsulated before it can be dispersed into aqueous-based products. The purpose of this study was to develop “all-natural” oil-in-water emulsions that could be used to incorporate vitamin E into functional food and beverage products. These emulsions were stabilized by a natural food-grade surfactant (Q-Naturale^®) isolated from the bark of the Quillaja saponaria Molina tree. The influence of oil phase composition (vitamin E to medium chain triglyceride (MCT) ratio), aqueous phase composition (glycerol to water ratio), and surfactant type (Q-Naturale^®versus Tween 80) on the size of the droplets produced by high pressure homogenization was examined. Small droplets could not be formed using only vitamin E acetate as the oil phase because of its very high viscosity, but they could be formed when ≥20% MCT was incorporated into the oil phase prior to homogenization. In the absence of glycerol, Q-Naturale^® was capable of forming emulsions containing relatively small droplets (d < 400 nm) from oil phases containing relatively high vitamin levels (60–80%). This droplet size could be decreased (d < 250 nm) by incorporating 50% glycerol in the aqueous phase prior to homogenization to increase its viscosity and decrease its interfacial tension. Tween 80 was more effective than Q-Naturale^® at producing small droplets when the oil phase contained low levels of vitamin E acetate (≤40%), but the opposite was true at higher vitamin levels. These results indicate that a natural surfactant (Q-Naturale^®) is effective at forming edible Vitamin E delivery systems that could be used in functional food and beverage applications.     

维生素E对致敏大鼠机体敏感性的影响

目的研究补充不同剂量、不同接触时间的维生素E对致敏SD大鼠机体敏感性的影响。方法取8周龄雌性SD大鼠,按体重随机分为5组,每组25只,每天经口分别给予不同剂量的维生素E(2.3、6.9、13.8mg/kg),在第2周、3周、4周、5周、6周时,每组分别取出5只动物,腹腔注射给予10 mg/只OVA致敏,一周后使用50 mg/只OVA刺激,检测各组动物血清中总Ig E、特异性Ig E和Ig G1、血浆中组胺、m MCP-1和细胞因子(IFN-γ,IL-4)的水平,大刺激后处死动物,取心脏、肝、脾、肾、胸腺、空肠、肠系膜淋巴结等脏器,并对这些脏器进行组织病理学观察。结果经口给予高剂量维生素E 6周,OVA产生的免疫学反应强度受到了显著的抑制作用,总Ig E、特异性Ig E、特异性Ig G1、IL-4以及组胺水平显著降低,IFN-γ水平显著升高,随接触时间的延长呈增高的趋势。且高剂量处理组动物免疫学反应强度显著低于OVA对照处理组,对致敏SD大鼠的机体敏感性起到了有效的调节作用。结论维生素E能够降低致敏动物机体对卵白蛋白的敏感性,也抑制了免疫系统对卵白蛋白产生的免疫学反应。     

Changes in vitamin content of powder enteral formulas as a consequence of storage

The thiamine, vitamin E (α-, γ- and δ-tocopherol) and vitamin A (all-trans and 13-cis-retinol) contents of four commercial powder enteral formulas (A, B, C and D) have been determined. The vitamin intake provided by the studied formulas was always above the US daily recommendations. Powder enteral formulas A and D were stored at 30 °C for up to 6 months with a water activity of 0.44 (A_w = 0.44), and formula A was also stored under atmospheric conditions for 3, 4 and 6 months. Formulas A and D kept at 30 °C and A_w = 0.44 suffered a gradual loss in vitamin content (from 3% to 4% after 1 month to 58–60% after 6 months). Formula A, stored at 30 °C under atmospheric conditions, underwent a slight reduction in vitamin content after 3 months, similar to that found after 1 month with A_w = 0.44, and from that time onward, this decreased steadily (to 30% after 6 months). The RDA of thiamine, vitamin E and vitamin A for women and men were met only when the powder enteral formulas were stored at 30 °C with A_w = 0.44 up to 1 month and without A_w up to 3 months. These results show that A_w and storage period have a marked effect on the stability of thiamine, vitamin E and A during the storage of powder enteral formulas and should be taken into consideration for the shelf-life of the product.     

Physicochemical characterization of alkali treated fractions from corncob and wheat straw and the production of nanofibres

Raw cereal materials (CM) (corncob and wheat straw) were alkaline treated to produce insoluble fibrous residues (IF) and soluble fibrous residues (SF). Physicochemical properties of each portion were evaluated. CM contained high amounts of dietary fibre (DF; 49.87–68.65%), while IF and SF mainly contained insoluble and soluble DF, respectively. CM and IF contained essential minerals (calcium, copper, iron, potassium, magnesium and phosphorus) while SF was free from heavy metals. CM and IF also exhibited DPPH radical scavenging ability (54.25 to 77.24%), good emulsification ability (3.73–5.29%) and emulsion stability (75.00–86.94%), mineral binding capacity (calcium, copper, iron, zinc), water holding capacity (2.82–6.01 g_water/g_sample) and oil holding capacity (2.61–4.00 g_oil/g_sample). IF and SF could be potentially developed into new functional food materials. The successful production of SF into nanofibres by electrospinning showed potential applications as delivery systems for bioactive and functional ingredients.     

Encapsulation of functional lipophilic components in surfactant-based colloidal delivery systems: Vitamin E,vitamin D,and lemon oil

The fabrication and stability of surfactant-based colloidal delivery systems (microemulsions and emulsions) suitable for encapsulation of lipophilic active agents (vitamins and flavours) was investigated. An emulsion titration method was used to study the influence of surfactant type (Tween 20, 60 and 80) and oil type (Vitamin E, vitamin D₃ and lemon oil) on the incorporation of lipophilic components into surfactant micelles. Oil-in-water emulsions were formed and then different amounts were titrated into surfactant micelle solutions. The influence of surfactant-to-oil ratio (SOR) and oil type on the formation of colloidal dispersions was examined using dynamic light scattering and turbidity measurements. SOR, oil type, and surfactant type had a pronounced influence on the nature of the colloidal dispersions formed. Microemulsions could not be formed using vitamin D or E in 1% Tween solutions, due to the relatively large size of the lipophilic molecules relative to the hydrophobic interior of the surfactant micelles. On the other hand, microemulsions could be formed from lemon oil at relatively high SORs. There was not a major impact of non-ionic surfactant type (Tween 20, 60 or 80) on the formation and properties of the colloidal dispersions. However, Tween 20 micelles did appear to be able to solubilise less lemon oil than Tween 60 or 80 micelles, presumably due to their smaller dimensions. This study provides useful information for the rational design of food grade colloidal delivery systems for encapsulating flavour oils, oil-soluble vitamins, and other functional lipids for application in foods and beverages.     

Influence of different dietary vitamin C levels on vitamin E and C content and oxidative stability in various tissues and stored m. longissimus dorsi of growing pigs

Both vitamin E and C have antioxidative properties and may act synergistically. To examine a possible interaction between vitamin E, C and oxidative stability in various tissues, 40 barrows (25–105 kg body weight) were allocated to four cereal-based diets (13.4 MJ digestible energy/kg, 168 g crude protein/kg, 140 mg dietary dl-α-tocopheryl acetate) which were supplemented with 0 (B), 150 (C100), 300 (C200) or 600 (C400) mg/kg crystalline ascorbic acid. The influence of storage time on these factors in m. longissimus dorsi samples (LD) was investigated. Samples of liver (LI), heart (HT), spleen (SP), backfat outer layer (BF) and LD were obtained. Dry matter, vitamin E, vitamin C and thiobarbituric acid reactive substances (TBARS) were analyzed in all investigated tissues and in addition color (L^∗, a^∗, b^∗ values) and drip loss measurements in LD at day 0, 1, 2, 3, 4 and 8 were collected. The treatments did not influence growth performance and slaughter data of the pigs. Neither the vitamin E nor the vitamin C content of investigated tissues showed differences due to feeding treatments. There was also a lack of response to the amount in TBARS. Parameters in LD samples were only affected by storage time and not by diets. The results show that dietary use of both vitamins simultaneously did not further improve qualitative characteristics of the investigated pork tissues.     

复合VE对延长富含油脂食品保质期的影响

为了延长富含油脂食品的保质期,对VE、Vc、柠檬酸对炒制花生粉油脂氧化酸败的抑制作用进行了研究。通过跟踪样品中过氧化值(POV)的变化来检测炒制花生粉油脂的氧化酸败程度。结果表明,VE、Vc、柠檬酸对炒制花生粉油脂氧化酸败确实有抑制作用,Vc、柠檬酸对VE的抗氧化作用有协同增效的作用,直接添加适当比例的VE、Vc、柠檬酸到炒制花生粉当中,可以延长富含油脂食品的保质期。     

Encapsulation of vanillin/cyclodextrin inclusion complex in electrospun polyvinyl alcohol (PVA) nanowebs: Prolonged shelf-life and high temperature stability of vanillin

We produced functional nanowebs, containing vanillin, having prolonged shelf-life and high temperature stability facilitated by cyclodextrin (CD) inclusion complexation. Polyvinyl alcohol (PVA) nanowebs incorporating vanillin/cyclodextrin inclusion complex (vanillin/CD-IC) were produced via electrospinning technique. The vanillin/CD-IC was prepared with three types of CDs; α-CD, β-CD and γ-CD to find out the most favourable CD type for the stabilization of vanillin. PVA/vanillin/CD-IC nanofibres, having fibre diameters around ∼200 nm, were successfully electrospun from aqueous mixture of PVA and vanillin/CD-IC. Our results indicated that vanillin with enhanced durability and high temperature stability was achieved for PVA/vanillin/CD-IC nanowebs due to complexation of vanillin with CD, whereas the PVA nanofibres without CD-IC could not effectively preserve the vanillin. Additionally, we observed that PVA/vanillin/γ-CD-IC nanoweb was more effective for the stabilization and slow release of vanillin suggesting that the strength of interaction between vanillin and the γ-CD cavity is stronger when compared to α-CD and β-CD.     

Influence of dietary selenium and vitamin E on quality of veal

Three groups of six calves each were fed a milk replacer and a starter concentrate for 15weeks. Calves of the first group received the basal diet containing selenium (Se) and vitamin E at 0.095-0.128mg and 30-33mg per kg of total solids, respectively. Calves of the second group received the basal diet supplemented with Se-enriched yeast to increase dietary Se concentration to 0.50mg/kg. The third group of calves received the latter diet supplemented with vitamin E to increase its concentration to 100mg/kg. There was no effect of diet on growth rate, digestibility of dry matter and Se, chemical composition of meat (M. Longissimus thoracis et lumborum), meat colour and fatty acid profile of meat lipids. The Se supplementation significantly increased Se concentration in muscle from 0.21 to 0.43mg/kg. The activity of glutathione peroxidase (GSH-Px) in muscle and liver tissue of Se-supplemented animals was increased by 56% and 67%, respectively, compared to the control. The combined supplementation of vitamin E and Se significantly improved the lipid stability of meat compared to the control diet, but not compared to the Se-supplemented diet. It can be concluded that dietary Se supplementation increases the concentration of Se and the GSH-Px activity in meat, but has limited potential for improving meat oxidative stability.     

The effect of dietary energy and vitamin E administration on performance and intramuscular collagen properties of lambs

The effect of different dietary energy levels, with or without injections of vitamin E, on growth, carcass traits and intramuscular collagen (IMC) characteristics of growing lambs was studied. Twenty-four Ile de France ram lambs were evaluated in a 2×2 factorial design involving different DL-α-tocopheryl acetate injections (C, control=0 and V=150IU/wk, i.m. for eight wk) and energy level (N, normal=7.61 and L, low=6.47MJ/kg DM). Growth and slaughter performance, and IMC characteristics were not influenced by diet. DL-α-tocopheryl acetate increased ADG during suckling, while it did not affect live weight, carcass weight and dressing percentage. Vitamin E injections reduced carcass shrinkage but also had a negative effect on pelvic limb percentage. The Longissimus muscle pH values were higher in V than in C lambs. DL-α-tocopheryl acetate reduced IMC maturity and muscle hydroxylysylpyridinoline crosslink concentration, more markedly in lambs fed low energy diets.     

Enhancement of the conjugated linoleic acid and vitamin A and E contents in goat milk through green fodder feeding

Twelve lactating crossbred goats (Sanan × Beetal) in early lactation were divided into two groups of six each. Group I was fed on fresh berseem fodder ( Trifolium alexandrinum ), whereas group II was fed on berseem fodder and concentrate mixture in 1 : 1 ratio to fulfil their nutritional requirements as per National Research Council (1981 ). Feed intake and milk yield were recorded daily, and milk samples were collected on 0, 30, 45 and 60 days of experimental feeding for the estimation of fat, vaccenic acid, conjugated linoleic acid (CLA), vitamins A and E, and total antioxidant activity. There was no effect ( P >  0.05) of dietary treatments on daily as well as total milk yield and milk fat, solids-not-fat and total solids, although average total CLA (mg/g fat) content in milk during the trial was higher( P <  0.01) in group I (18.92) in comparison to group II (10.94). Vitamin A content averaged 0.46 and 0.27 µg/mL and vitamin E, 1.20 and 1.38 µg/mL in milk of groups I and II, respectively, were higher in the berseem-fed group ( P <  0.01) and total antioxidant activity of milk was also higher ( P <  0.01) in group I than in group II.     

Influence of vitamin E supplementation on spontaneous oxidized flavour of milk in dairy buffaloes

Twenty-four Murrah buffaloes (60 days pre-partum) were divided into four equal groups (T ₁ , T ₂ , T ₃ and T ₄ ) and were supplemented with 0, 1000, 1500 and 2000 IU α-tocopheryl acetate per day up to 30 days of lactation, and half of these doses from 30 to 60 days of lactation. Milk samples collected fortnightly were analysed for vitamin E, fat, and development of oxidized flavour, with and without copper addition by a panel of judges, and chemically by the thiobarbituric acid test. Scores for oxidized flavour ranged from 0 to 10 with 0–4 as definite, 5–7 as light and 8–10 having no defect. The α-tocopherol content in milk fat (µg/g) averaged 20.55, 25.56, 29.98 and 31.38 in T ₁ , T ₂ , T ₃ and T ₄ groups, respectively. The addition of Cu in the milk significantly increased milk fat oxidation. Better stability of milk in T ₃ and T ₄ groups was observed, which might be due to a higher level of milk α-tocopherol. Addition of 1500 IU α-tocopheryl acetate in the diet of buffaloes helped in improving the oxidative stability of milk.     

Preparation and characterization of phytosterol-loaded nanoparticles with sodium caseinate/dextran conjugates

Sodium caseinate (SC)/dextran conjugates were prepared via Maillard reaction under controlled dry-heating conditions. Moreover, the nanoparticles of phytosterols (PS) encapsulated by SC or SC/dextran were produced using the emulsion evaporation method. The encapsulation efficiency (78.81 ± 5.22%) of PS in SC/dextran nanoparticles was higher than that (73.5 ± 2.78%) in SC nanoparticles. Compared with the compact and dense structure of SC nanoparticles, SC/dextran nanoparticles existed as relatively loose aggregates. The result of differential scanning calorimetry demonstrated that the encapsulation of PS greatly decreased its crystallinity. The released rates of PS from SC and SC/dextran nanoparticles under acidic gastric conditions were 8.59% and 4.73%, respectively. After 7 h of intestinal digestion, the released rate (52.19%) of PS from SC/dextran nanoparticles was significantly higher than that from SC (32.67%) nanoparticles. Therefore, SC/dextran conjugates prepared by the Maillard reaction are more suitable to be used as wall material for the nano-encapsulation of PS.     

关于改善维生素C加E咀嚼片黑色斑点的研究

目的 从配方工艺的角度, 找出维生素C加E咀嚼片产生黑色斑点的根源并对其解决, 保证该产品的质量。方法 通过稳定性考察样品的送检情况, 开展原辅材料的排除性工艺试验, 小试制粒、压片和加速考察调整问题配方。结果 工艺调整后, 片剂黑色斑点现象得到了有效的改善。结论 产品配方中的维生素C与明胶发生了美拉德反应, 引起了褐变, 导致片剂产生黑色斑点。经优化后的配方工艺, 问题得到彻底解决。     

Development of novel pea flour‐based nanofibres by electrospinning method

The aim of this study was to produce pea flour and hydroxypropyl methylcellulose (HPMC)‐based novel nanofibres using electrospinning method. The effects of pH, pea flour and HPMC concentration on apparent viscosity, electrical conductivity of electrospinning solutions and nanofibre characteristics were studied. Solutions were prepared at different pH values (7, 10, 12), with different pea flour concentrations (1%, 2% w/v) and HPMC concentrations (0.25%, 0.5%, 1.0% w/v). For all pea flour concentrations, k values increased significantly with increase in pH and HPMC concentration. It also increased with increase in pea flour concentration for basic solutions. Pea flour concentration increased diameter and water vapour permeability (WVP) values of nanofibres. This study showed that electrospinning was a promising method for fabrication of homogenous pea flour and HPMC‐based nanofibres to be used in packaging industry.