浅谈维生素A强化食用油

叙述了食用油的营养强化剂、营养强化食用油与普通食用油的区别及其相关标准和推广应用前景.     

维生素A强化食用油

由于我国维生素A缺乏依然比较严重,了改善这一状况,国家采用在食用油中强化维生素A方式来增加我国居民维生素A的摄入量。 首先来认识一下维生素A。维生     

强化食用油中维生素A的检测

本文提出一种利用三氯乙酸氯仿溶液与维生素A反应的分光乐度法，检测强化食用油中维生素A。反应产物在620nm有最大吸收，在0.15-3.35μg/ml范围内吸光度与浓度呈线性关系。回收率在93.3%以上，RSD小于3.5%。样品中低于1.0mg/ml的维生素D2和0.8mg/ml的β-胡萝卜素不干扰测定，测定强化食用油中的维生素A的结果与国标得到的结果基本一致。     

强化酸牛奶中维生素A与C的稳定性

在实际生产的条件下,用不同工业形式生产的维生素 A 和 C 强化的普通酸牛奶和木莓风味的低脂肪酸牛奶奶样。在处理后,应立即将酸牛奶奶样于3℃中保藏6周,尔后每两周一次分析 pH、可滴定酸度、维生素 A 和 C。数据表明强化酸牛奶中的两种维生素逐渐减少,而维生素 C 的减少率要比维生素 A 高一些。然而,每227g 一罐的普通的或加香的酸牛奶中维生素 A 与 C 的强化量分别是10,000国际单位(IU)与300mg,它在3℃中保藏6周后仍然100%提供了美国推荐的这两种维生素的日容许量。这一强化标准并未明显改变酸牛奶样品的 pH值、可滴定酸度和感官性质。     

强化食用油中维生素A的检测

本文提出一种利用三氯乙酸氯仿溶液与维生素A反应的分光光度法 ,检测强化食用油中维生素A。反应产物在62 0nm有最大吸收 ,在 0 .15～ 3 .3 5μg/ml范围内吸光度与浓度呈线性关系。回收率在 90 .3 %以上 ,RSD小于 3 .5 %。样品中低于1.0mg/ml的维生素D2 和 0 .8mg/ml的β-胡萝卜素不干扰测定。测定强化食用油中的维生素A的结果与国标得到的结果基本一致     

维生素A稳定性影响因素研究进展

维生素A醇及其酯类衍生物的特殊结构,使维生素A成为生命体不可缺少的微量营养物质和化妆品常用添加剂。维生素A醇及其酯类衍生物中5个共轭双键及羟基或酯基的存在也使其化学性质活泼,在光、氧、热等因素作用下极易发生氧化、脱水和聚合等反应,导致结构变化而降低其保留率及生物利用率。工业生产过程中通常采用乳化或者包埋处理维生素A来隔绝生产、储存和使用过程中与上述影响因素的接触。本文对维生素A醇及其酯类衍生物在光、氧、热和溶剂等因素影响下的稳定性及其结构和保留率的变化,反应机理进行综述,为进一步提高维生素A的稳定性提供理论参考。     

《营养强化 维生素A食用油》国家标准实施

由国家粮食局提出,全国粮油标准化技术委员会归口,国家粮食局标准质量中心组织,国家粮食局科学研究院、国家粮食储备局西安油脂科学研究设计院、中粮食品营销有限公司、北海粮油工业（天津）有限公司负责起草制定的《营养强化维生素A食用油》国家标准于2008年1月1日起实施。     

乳制品中维生素A稳定性的研究进展

对加工工艺、储藏条件、光、氧气和脂肪质量分数等因素对液态奶或奶粉中维生素A稳定性影响的研究进展及其降解动力学进行了综述,并对如何提高其在产品中的稳定性进行了讨论.     

维生素A酯类的稳定性及热降解动力学研究

研究了光、温度、氧化剂、金属离子、酸碱、抗氧化剂、防腐剂、溶剂类型等因素对维生素A醋酸酯(RA)和维生素A棕榈酸酯(RP)稳定性的影响。结果表明,其均对光和高温敏感;H2O2存在时RA不稳定;Fe3+和Cu2+引起的损失较大,Al3+引起的RA的损失较大;盐酸存在时都不稳定;在碱、抗氧化剂、防腐剂存在时都较稳定;维生素A酯类在正己烷中比在乙醇中稳定。多数情况下,RP的稳定性高于RA。维生素A酯类的热降解符合一级反应,RA和RP热降解反应的活化能分别为80·59kJ/mol和100·41kJ/mol。     

强化维生素A食品对儿童血清VA变化的观察

对天津市４－６岁儿童６４名，随机分两组，实验组每日食用强化ＶＡ６００ＩＵ的加餐食品，对照组食用未强化的同样食品共计７０天，实验前后血清ＶＡ含量及缺乏体征，显示实验组血清ＶＡ含量上升，缺乏体征减少，与比较有显著差异，表明 给儿童经常食用强化ＶＡ加餐食品是必要而安全的。     

VD强化及其稳定性研究进展

近年来,国内外VD缺乏的现象越来越受到人们的重视。本文对目前VD的补充、强化、强化载体以及在强化载体中的稳定性方面的研究进展作一综述,以期为加强我国VD强化食品研发力度和增加VD的有效摄入量提供一定的参考。     

代乳饮料稳定性研究

用植脂末替代调配酸乳饮料中的奶粉原料，并添加了适量的乳酸钙，制作代乳饮料。对影响饮料稳定性的因素进行了研究，通过正交试验确定稳定剂的最佳配比。结果表明添加白砂糖10％、柠檬酸0．18％、乳酸0．10％、植脂末5．0％、乳酯钙0.20%、单甘酯0.12%、羧甲基纤维素钠（CMC）0.10%和黄原胶0．050％时产品稳定性好，代乳饮料口感和奶粉调配的乳饮料相差不大。     

辅酶Q_(10)食用油的开发应用

从辅酶Q10(CoQ10)食用油的稳定性,人体吸收利用效果,食用安全性及其推荐量,CoQ10与食用油的协作关系,以及与油中伴随物维生素E产生的协同抗氧化作用等方面进行综述。论述了开发CoQ10食用油的重要意义,介绍了CoQ10食用油的制作工艺,并就CoQ10添加前后对食用油色泽、酸值和过氧化值影响以及传统的煎炸、清炒方式对CoQ10食用油质量指标影响进行实验验证;最后分析展望了辅酶Q10食用油的适宜人群及其应用前景。     

Effects of sterilization, packaging, and storage on vitamin C degradation, protein denaturation, and glycation in fortified milks

Monitoring the nutritional quality of dietetic milk throughout its shelf life is particularly important due to the high susceptibility of some vitamins to oxidation, and the continuous development of the Maillard reaction during storage.The objective of this paper was to evaluate the vitamin C content and protein modification by denaturation and glycation on fortified milk samples (growth milks) destined for 1- to 3-yr-old children. The influences of the sterilization process, formulation, packaging, and storage duration at ambient temperature in the dark were studied. Vitamin C degradation was particularly influenced by type of packaging. The use of a 3-layered opaque bottle was associated with complete oxidation of vitamin C after 1 mo of storage, whereas in the 6-layered opaque bottle, which has an oxygen barrier, the vitamin C content slowly decreased to reach 25% of the initial concentration after 4 mo of storage. However, no significant effect of vitamin C degradation during storage could be observed in terms of Maillard reaction, despite the fact that a probable impact occurred during sterilization. Furosine content and the FAST (fluorescence of advanced Maillard products and soluble tryptophan) index-indicators of the early and advanced Maillard reaction, respectively-were significantly higher in the in-bottle sterilized milk samples compared with UHT samples, and in fortified milk samples compared with cow milk. However, after 1 mo, the impact of storage was predominant, increasing the furosine level and the FAST index at similar levels for the differently processed samples. The early Maillard reaction developed continuously throughout the storage period.In conclusion, only packaging comprising an oxygen and light barrier is compatible with vitamin C fortification of milk. Furthermore, short storage time or low storage temperature is needed to retard vitamin C degradation, protein denaturation, and development of the Maillard reaction.     

高锌牛乳的研究开发

研究了以生鲜牛奶为原料,以乳酸锌进行营养强化的高锌乳制品。通过实验确定了锌源,生产工艺和配方,结果表明,产品安全,性能稳定,乳制品锌含量为0．01g/L。     

食用油脂的安全性

介绍了造成油脂老化的3种反应类型,即热分解反应、热氧化反应及热聚合与热缩合反应。产生油脂老化的主要因素有油脂的种类、油温、与氧气接触面积、金属催化剂、油炸物水分含量和加工方式等。为保证食用油脂的安全性,建议烹饪时油温最好不要超过150～180℃,并做好厨房的通风换气工作。     

Effect of flaxseed oil fortified with vitamin e and phytosterols on antioxidant defense capacities and lipids profile in rats

The main proposal of this study was to evaluate in vivo whether flaxseed oils fortified with micronutrients would have beneficial effects on lipid profile and antioxidant status in high-fat fed rats. Male Wistar rats were fed synthetic diets containing 10% of flaxseed oil (FO), phytosterols (PS) fortified FO (PS-FO), vitamin E (V(E) ) fortified FO (V(E) -FO), V(E) , and PS fortified FO (V(E) -PS-FO), respectively, for 4 wk. The results showed that V(E) fortified FO enhanced the enzymatic (SOD and GPX) and nonenzymatic (GSH and V(E)) antioxidant system, lowered the lipid peroxide (TBARS) concentration compared with FO (P < 0.05). And FO fortified with PS significantly reduced the plasma TG, TC and LDL-C levels, and hepatic TG and TC levels of rats compared with FO (P < 0.05), but had no significant effect on antioxidant defense capacities. Combined addition of V(E) and PS in FO had a synergetic effect. These results indicated that flaxseed oils fortified micronutrients V(E) and PS may contribute to reduce the risk factors of cardiovascular disease (CVD) by improving plasma antioxidant defenses and lipids profiles. PRACTICAL APPLICATION: Flaxseed oil usually contains greater than 50% of alpha-linolenic acid (ALA) and is a desire origin for n-3 PUFA. But consuming high dose of n-3 PUFA could lead to oxidative damage through free radical-chain reaction in cellular and subcellular membranes. Our studies showed that a regular intake of V(E) and PS fortified flaxseed oils increased antioxidant defenses and ameliorated lipids profile in high-fat fed rats, and these indicated that the flaxseed oil fortified with these micronutrients might reduce the incidence of CVD.