乳化食品中油脂氧化分析及其货架期评价方法的研究进展

油脂氧化是导致乳化食品变质的主要原因。油脂中的不饱和脂肪酸发生氧化,不仅会降低乳化食品的营养价值,还会产生不良风味、有害成分,进而影响乳化食品货架期和食用安全。相对于纯油体系,以乳化形式存在的油脂在高油-水界面比下极易发生氧化,缩短乳化食品的货架期。为明确乳化食品中油脂氧化分析以及其货架期评价方法,在介绍乳化食品中油脂氧化的基本过程的基础上,综述了乳化食品中油脂氧化分析方法（过氧化值、共轭二烯值、硫代巴比妥酸值、茴香胺值、挥发性物质含量）以及货架期的评价方法,为乳化食品中油脂氧化程度分析及其货架期预测提供参考。     

二酰甘油油脂的特性及其生产工艺研究进展

二酰甘油油脂对肥胖和与体重相关的生理失调的防治有功效.在动物和人体中,二酰甘油能够减少脂肪的积累.二酰甘油的生理功效归根于它的代谢途径与三酰甘油不同.二酰甘油的物理化学性质,如熔点、发烟点、结构多态性,也与三酰甘油有显著差异.并介绍二酰甘油油脂的生产工艺.     

乳化剂在制面条中的应用

食用乳化剂是食品添加剂的一种,已在许参食品中得到应用。现将在面条生产中广为利用的乳化剂脂肪酸甘油脂和乳化油脂作一简要介绍。一、脂肮酸甘油脂脂肪酸甘油脂(或叫甘油脂肪酸酯)是食用乳化剂中在食品中最广为使用的乳化剂之一,它的效果已经得到公认。通常,被称为单甘油脂的乳化剂,是甘油分子中的一个     

植物油体的提取及其乳化体系研究进展

油体是植物组织中贮存油脂的特殊细胞器,三酰甘油构成了油体的疏水性内核,磷脂分子和油质蛋白构成油体外层的单层膜结构,赋予油体良好的稳定性,能够抵抗干旱、高温等外界不利条件,并能保持油体在体外水溶液中的稳定,具有广阔的开发前景。本文对植物油体的组成和结构、植物油体的提取及油体乳液乳化体系（如油体乳液乳化体系组成、乳化体系的稳定性及其乳化机理）等的研究进展进行综述,以期为水（酶）法提取植物油过程中乳液的有效破乳和植物油体产品的开发、应用提供参考。     

小麦、水稻和玉米胚芽的营养功能及胚芽食品的研究进展

小麦、水稻和玉米作为我国三大主粮,其籽粒中的胚芽富含多种营养素以及黄酮类物质、植物凝集素、植物甾醇、谷维素等多种植物化合物,是制备功能性食品的良好原料。本文综述了三大主粮的主要营养成分与生物活性成分,同时介绍了三种谷物胚芽在食品加工中的应用,包括在植物蛋白饮料、功能性油脂、面粉及其制品等一些食品和制品。     

sn-1,3位专一性脂肪酶在食品中的应用

脂肪酶在食品中的应用已有几十年的历史,由于油脂中三酰甘油的1,3位和2位的脂肪酸对油脂的理化、营养和生理特性方面有较大的差异,因此专一性水解三酰甘油1,3位的脂肪酶成为研究的热点。由于sn-1,3位专一性脂肪酶选择性地水解三酰甘油的1位和3位,因此广泛的用于三酰甘油的修饰。国内外大量的研究表明,sn-1,3位专一性脂肪酶适用于生产结构脂质、母乳脂肪替代品、类可可脂和甘油二酯等,获得价格低廉而活性高的酶、高效的酶固定化技术和研发酶反应器是今后研究的重点。     

酶法改性微藻油脂制备功能性油脂的研究进展

多不饱和脂肪酸是一类对人体健康有益的生物活性物质,微藻油脂富含多不饱和脂肪酸,是天然可食用的潜在油源。利用微藻油脂开发制备型功能性油脂,替代动植物天然功能性油脂,不仅可提高天然功能性油脂的品质,解决供应问题,而且有望得到新的功能性油脂制品。对酶法制备功能性油脂的方法、常见微藻的油脂含量及其油脂的脂肪酸组成进行综述,并对酶法改性微藻油脂制备富含多不饱和脂肪酸的单酰甘油酯、结构三酰甘油酯、功能性磷脂等功能性油脂的研究进展进行了介绍。酶法改性微藻油脂制备功能性油脂是高值化利用微藻油脂的新途径。     

超微细处理技术在功能性油脂加工中的应用

介绍了超微粉碎、微胶囊化、微乳化和超高压均质4种常用的超微细处理技术在功能性油脂加工中的应用情况,并对其实际应用效果进行了评述。分别采用不同的超微细处理方法,可在提高功能性油脂出油率、功能性成分的释放速度和释放量,改善功能性油脂的理化特性和氧化稳定性,增强保健功效等方面发挥显著作用,超微细处理技术在功能性油脂加工中应用前景广阔。     

植物种子油脂合成代谢及其关键酶的研究进展

植物种子油脂是脂肪酸和甘油合成的高级脂肪酸甘油酯,主要以三酰甘油的形式储存于种子里。植物脂肪酸和三酰甘油具有重要的生理功能,其生物合成途径复杂:在质体中进行脂肪酸的从头合成,合成的脂肪酸运送到内质网中进行三酰甘油组装,期间还涉及脂肪酸的去饱和。本文综述了植物脂肪酸生物合成、三酰甘油合成与调节过程中的关键酶,并对WRI、LEC、Dof等调控因子对合成过程中关键酶的调控作用进行综述,对植物种子油脂代谢遗传工程应用研究有较大的意义。     

微胶囊技术在功能性油脂生产中的应用

在介绍微胶囊技术基本原理的基础上,分析其在功能性油脂生产中的意义,着重探讨了几种常用的微胶囊壁材和生产技术,总结了功能性油脂微胶囊的研究现状及在食品工业中的应用.功能性油脂微胶囊化不仅可保护其中的功能成分,防止氧化,而且产品有较优的稳定性、流动性,以及较高的生物消化率,因而微胶囊技术在功能性油脂生产中具有广阔的开发和应用前景.     

AN ATTEMPT AT ESTIMATING THE SIZE DISTRIBUTION OF OIL GLOBULES IN EMULSION TYPE COMMERCIAL FOODS BY MEANS OF A MODIFIED CENTRIFUGAL PHOTOSEDIMENTOMETER

The size distribution of oil globules in emulsion type foods (mayonnaise, cow's milk, and ice cream) was estimated with the homogeneous (simple dilution) technique in the modified disk-centrifugal photosedimentometer, for which data were available for calculating the cumulative size distribution. It was confirmed that, in many of the tested samples, a large number of oil globules are in the sub-micron range. These very small globules have an important effect on the rheological properties of emulsion type foods.     

Singlet Oxygen‐Related Photooxidative Stability and Antioxidant Changes of Diacylglycerol‐Rich Oil Derived from Mixture of Olive and Perilla Oil

Abstract: This study investigated the oxidative stability and antioxidants changes in diacylglycerol (DAG)‐rich oil under singlet oxygen. DAG‐rich oil was derived from triacylglycerol (TAG) oil of extra virgin olive and perilla oil mixture by hydrolysis and re‐esterification using lipases. The oxidation of oils was performed at 25 °C for 48 h under singlet oxygen produced with chlorophyll b under light, and was evaluated by headspace oxygen consumption and peroxide value (POV). The oxidation of DAG‐rich oil was higher and faster in the co‐presence of light and chlorophyll than in their single presence. DAG‐rich oil was more oxidation‐susceptible than TAG oil. There was no significant change in fatty acid and lipid subclass compositions in DAG‐rich oil during the photooxidation. Tocopherols were degraded, whereas polyphenols weren't during phootooxidation of DAG‐rich oil. The oxidation of DAG‐rich oil was well‐correlated with tocopherol contents, not with polyphenol contents, indicating that tocopherols were effective antioxidants in the singlet oxygen‐related phootooxidation of DAG‐rich oil. The results suggested that the oxidative stability of DAG‐rich oil under singlet oxygen be improved by a precise control through retention of tocopherols. Practical Application: The results of this study can be applied to the utilization of diacylglycerol oils to the area of functional edible oils with good oxidative stability.     

Phytosterol oxidation in oil-in-water emulsions and bulk oil

Dietary plants sterols (phytosterols) have been shown to lower plasma cholesterol level in humans. Since phytosterols may protect against coronary heart diseases, they are being incorporated into functional foods. However, phytosterols are susceptible to oxidative degradation. The purpose of this study was to evaluate the formation of phytosterols oxidation products (POPs) in oil-in-water emulsions and bulk corn oil. The extent of lipid oxidation was monitored by measuring the lipid hydroperoxides and hexanal, whereas 7-keto derivatives of phytosterols were determined by gas chromatography to follow sterol oxidation. A higher POPs level and formation rate was found in the oil-in-water (o/w) emulsion than in the bulk oil. Interfacial tension measurements showed that phytosterols had a high degree of surface activity, which would allow them to migrate to the oil–water interface of the emulsion droplets where oxidative stress is high.     

乳化体系中花生油氧化稳定性的研究

主要探讨花生油乳化体系中乳化剂类型、用量、pH值、EDTA、温度等对花生油氧化稳定性的影响,结果显示:乳化剂种类和pH对于乳状液体系的氧化稳定性有显著影响,阴离子乳化剂SDS稳定的乳化液,pH4.0的氧化速率最快;非离子乳化剂Tween20稳定的乳化液,pH的影响不是很显著;阳离子乳化剂CTAB稳定的乳化液,随着pH的升高,氧化速率变快。乳化液体系中微量金属离子对于体系也有相当大的影响,随着金属离子螯合剂EDTA浓度的增加,其乳化体系中花生油的氧化速率显著降低。乳化剂用量也会影响体系的氧化稳定性,随着乳化剂用量的增加,乳化乳化体系中花生油的氧化稳定性降低。     

大豆蛋白/壳聚糖凝聚法制备微藻油乳液及其稳定性研究

微藻油富含ω-3多不饱和脂肪酸二十二碳六烯酸(DHA)与二十碳五烯酸(EPA),在液体食品中的应用日趋广泛。但是微藻油极易在食品加工、保藏和消化过程中发生氧化劣变;同时脂溶性的微藻油难以添加至液体食品中。因此,改善和提高微藻油的稳定性是其应用到食品中的关键问题。本文利用大豆分离蛋白(SPI)/壳聚糖(CS)复合凝聚物(Coacervate)制备了微藻油乳液。由于乳液的氧化稳定性很大程度上依赖于其物理稳定性,本文系统研究了微生物谷氨酰胺转氨酶(m TGase)交联对微藻油乳液物理稳定性及氧化稳定性的影响。实验结果表明,在p H为6.0,CS/SPI比例为0.1 g/g,m TGase浓度为25 U/g SPI的条件下,m TGase对SPI/CS凝聚物的交联效果最好。m TGase交联明显改善了微藻油乳液的物理稳定性及氧化稳定性,并显著提高了微藻油的乳化效率。通过此方法制备的微藻油乳液产品可应用于豆奶等液体蛋白饮料从而达到强化DHA的目的。     

鱼油在食品领域中的应用技术综述

对鱼油在食品领域中的应用技术进行综述。由于具有独特的营养功能,鱼油的应用十分广泛。中国居民目前对二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)摄入不足,因而鱼油在食品中的应用十分必要。目前市场上已有多种鱼油应用于各类食品中。在应用过程中,鱼油的氧化稳定性问题一直是研究热点,选择不同的添加形式(纯鱼油、乳状液和微胶囊)并采用某些新工艺可有效提高氧化稳定性。鱼油应用于食品在技术和商业方面的发展前景均十分广阔。     

Oxidation Stability of O/W Emulsion Prepared with Linolenic Acid Enriched Diacylglycerol

The sn‐1,3‐regiospecific Rhizomucor miehei lipase (Lipozyme RM IM) was employed to produce structured diacylglycerol (SL‐DAG), which contained 67.3 mol% DAG with 27.2 area% of C18:3. To investigate the oxidative stability of the SL‐DAG in emulsion form, 5% oil‐in‐water (O/W) emulsions were prepared with 200 and 400 ppm sinapic acid. It was shown that the hydroperoxide values of the control (without any antioxidant) was the highest (117.7 meq/L) on day 43 of storage and thereafter the value decreased. However, the emulsions with 200 and 400 ppm sinapic acid resulted in slow oxidation degree until day 64 of storage (30.3 and 7.3 meq/L, respectively). Aldehyde measurements for the 200 ppm sinapic acid emulsion (12.8 mmol/mol) and the 400 ppm sinapic acid emulsion (7.5 mmol/mol) also showed better oxidative stability than that for the 200 ppm catechin emulsion (27.4 mmol/mol) and the control (52.7 mmol/mol). Although the SL‐DAG in the emulsions contains high levels of polyunsaturated fatty acids, the degree of oxidation in the emulsions can be reduced when sinapic acid is used as an antioxidant.     

Production of palm oil-based diacylglycerol using Lecitase Ultra-catalyzed glycerolysis and molecular distillation

Diacylglycerol (DAG) was prepared via glycerolysis of palm oil catalyzed by Lecitase Ultra (LU), a novel phospholipase from the fusion of lipase genes from Thermomyces lanuginose and phospholipase genes from Fusarium oxysporum. Glycerolysis was performed in a solvent-free system. The optimized reaction conditions were: a glycerol/palm oil mole ratio of 7.5:1, initial substrate water content of 5%, substrate enzyme load of 2%, reaction temperature of 40°C, and reaction time of 8 h. In a scale-up reaction, a DAG content of 59.5% in the lipid layer was achieved. Through a two-step molecular distillation, the composition of the target product was 88.1% DAG, 2.8% TAG, 9.0% MAG, and 0.1% FFA. The fatty acid composition of the DAG oil, determined using GC-MS, was enriched compared with the original palm oil.     

Dispersion Stability of O/W Emulsions with Different Oil Contents Under Various Freezing and Thawing Conditions

Freezing and thawing of oil‐in‐water (O/W) emulsion‐type foods bring about oil–water separation and deterioration; hence, the effects of freezing and thawing conditions on the destabilization of O/W emulsions were examined. The freezing rate and thawing temperature hardly affected the stability of the O/W emulsion. O/W emulsions having different oil fractions were stored at temperatures ranging from –30 to –20 °C and then thawed. The stability after thawing depended on the storage temperature, irrespective of the oil fraction of the emulsion. A good correlation was found between the time at which the stability began to decrease and the time taken for the oil to crystalize. These results indicated that the dominant cause for the destabilization of the O/W emulsion during freezing and thawing is the crystallization of the oil phase and that the effects of the freezing and thawing rates on the stability are insignificant.     

Iron-Catalyzed Oxidation of Menhaden Oil as Affected by Emulsifiers

The ability of Tween 20 and whey protein isolate (WPI) to influence lipid oxidation was investigated by evaluating the effects of emulsifier concentration and physical location on iron-catalyzed oxidation of emulsified Menhaden oil. Addition of Tween 20 or WPI to the aqueous phase of a 0.5 wt% Tween 20 stabilized emulsion increased lipid oxidation as determined by both thiobarbituric acid reactive substances (TBARS) and lipid peroxides. Tween 20 (2.0 wt%) and WPI (0.05–1.0 wt%) combinations inhibited TBARS formation 23–60%. Oxidation of a WPI-stabilized emulsion decreased with decreasing pH (3–7) but in a Tween 20 stabilized emulsion oxidation increased with decreasing pH. The low oxidation rate for the WPI-stabilized emulsion at pH 3 was increased when Tween 20 displaced WPI from the droplet interface. Results indicate that the oxidative stability of emulsifed Menhaden oil could be increased by controlling emulsifier type, location and concentration.