煎炸食物吸油机理探讨

探讨了煎炸食物生产过程中的油脂吸收机理,包括毛细管吸油机理、冷凝机理、表面活性剂理论及粘附理论等,理解这些吸油机理,有助于人们更好地控制煎炸食物的油脂吸收过程。     

煎炸食物中油脂极性组分的提取及分析

以油炸花生、油条、麻花3种中式煎炸食物为研究对象,选取10种溶剂配方提取其内含油脂,基于制备型快速柱层析和高效体积排阻色谱,深入分析煎炸食物内油脂极性组分的构成比例。结果表明:在提取煎炸食物中油脂极性组分时,石油醚对油炸花生和麻花的提取结果最高,正己烷-异丙醇(体积比4∶1)对油条的提取结果最高,与石油醚的无显著性差异。在测定煎炸食物中油脂极性组分时,可选用石油醚作为提取溶剂。石油醚提取所得油炸花生油脂中极性组分含量为4.5%,主要为氧化甘油三酯单体类和甘油二酯类,油条油脂中极性组分含量为28.8%,主要为甘油三酯聚合物类,麻花油脂中极性组分含量为8.0%,主要为甘油三酯聚合物类、氧化甘油三酯单体类和甘油二酯类。     

油炸食品及其煎炸油卫生质量检测指标关系探讨

该实验在郑州市区53个煎炸点,取油炸食品及其相应煎炸油,按国家标准方法分别对不同煎炸时间油炸食品及其煎炸油的酸价、过氧化值、羰基价三个指标进行检测,调查油炸食品及其煎炸油卫生质量,探讨两者间卫生指标关系。     

油炸食品吸油过程的机制分析

以油炸冷冻土豆条为研究对象,研究了油炸过程和冷却过程中,样品表面温度和内部温度的变化,以及因温度变化引起的蒸汽压力的变化。测量数据表明:在油炸过程中,食品的内部温度升至水的沸点后不再增加,食品的表面温度很快升至比油温低20～30℃左右就不再变化;在冷却过程中,食品的表面温度很快下降;而食品内部温度降低较慢。对吸油的两种驱动机制进行了比较分析,最终确定毛细吸力对吸油的影响较小,大部分的吸油是因为食品内水蒸汽冷凝而带来的表面壳层孔洞内外压力差而导致的。     

液相色谱联用电化学还原装置检测油炸食品中叔丁基对苯二酚

目的:采用液相色谱联用电化学还原装置检测油炸食品中叔丁基对苯二酚。方法:样品经石油醚提取得到油脂,再加入乙腈萃取,离心过滤,上机测定。结果:在0.50 50.00mg/L浓度范围内线性良好,相关系数r=0.9971,方法最低检测限为0.05mg/L,RSD=1.78%,加标回收率84.20 91.21%。结论:该方法前处理简便快捷,采用电化学方式还原了油炸食品在生产及储存过程中被氧化的TBHQ,精密度、准确度好,检测结果准确可靠。     

离子迁移谱法快速鉴别煎炸老油

目的建立基于离子迁移谱的快速鉴别煎炸老油的鉴别方法。方法油样经正己烷50倍稀释、混匀,进样量为4.0μL,在进样口温度为170℃,迁移管温度为60℃的离子迁移谱条件下进行检测,样品测试时间为20 s。将采集的油样离子迁移谱图利用化学计量学方法进行分析,建立煎炸老油鉴别模型。结果运用主成分分析法(PCA)对两类油脂的谱图信息进行分类,两类油脂能明显分开,效果良好。采用递归支持向量机法(R-SVM)对煎炸老油建立判别模型,十折交互检验正确判别率最高达98.8%。结论本方法无需复杂前处理、检测时间短,有机试剂用量小,操作简单快速,结合化学计量学的分析方法建立的煎炸老油的鉴别模型准确度高,适用于煎炸老油的快速鉴别,为我国食用油质量安全监管提供了一种新方法。     

油炸食品中丙烯酰胺的形成及减少措施

食品在加工过程中,特别是富含天门冬氨酸和还原糖的物质在高温(120℃以上)加工过程中会产生丙烯酰胺.试验表明,丙烯酰胺对动物有致癌性、神经毒性、生殖发育毒性的作用,但还没有足够的证据表明,食品加工过程中产生的丙烯酰胺对人体有致癌性.然而丙烯酰胺作为食品加工过程中产生的不受欢迎的物质,仍应尽量减少摄入.丙烯酰胺主要存在于油炸、高温烘焙的食品中,减少油炸食品中丙烯酰胺含量的途径主要有:减少或消除形成丙烯酰胺的前体物质;抑制加工过程丙烯酰胺的生成;破坏或使食物中形成的丙烯酰胺重新反应;在食品消费前将形成的丙烯酰胺去除.同时,改变以油炸和高脂肪食品为主的饮食习惯,尽量减少或防止丙烯酰胺可能对人体造成的伤害.     

油炸食品含油率研究

油炸食品是一种传统方便食品,由于其特殊风味倍受人们喜爱,而含油率已被认定为影响其安全性重要因素。该文探讨油炸食品含油机理,分析原料性质对含油率影响,并提出降低含油率措施及其检测技术。     

Application of protein-based edible coatings for fat uptake reduction in deep-fat fried foods with an emphasis on muscle food proteins

BackgroundDeep-fat frying is a common cooking method where fat or oil is used as the heat transfer medium, in direct contact with the food at a temperature above the boiling point of water. During the deep fat frying method, oil not only serves as a heating medium but also absorbs into food, increasing the total fat content. As a result, consumption of deep-fat fried foods has been associated with coronary heart diseases, obesity and type 2 diabetes. Selection of an appropriate food coating before frying may act as a barrier to moisture loss, which is important commercially, and also reduce fat uptake during frying.Scope and approachThis paper succinctly reviews different protein sources for edible coatings and compare them with muscle food proteins which were used in deep-fat fried foods.Key findings and conclusionsProtein-based coatings have been explored as potential coating materials in fat-uptake reduction. Comparatively, proteins are able to form films with better mechanical and barrier properties than polysaccharides. Application of muscle food proteins (myofibrillar proteins) as coatings, which are rich in these proteins, is novel and could be product-friendly for deep-fried muscle foods.     

毛细管气相色谱法测定油炸食品中特丁基对苯二酚的残留量

目的建立毛细管气相色谱法测定油炸食品中特丁基对苯二酚的残留量。方法采用毛细管气相色谱法。色谱柱为HP-5弹性石英毛细管柱(30 m×0.25 mm,0.25μm);载气为氮气;检测器为FID;进样口和检测器温度均为250℃;柱温为220℃,保持15 min。结果特丁基对苯二酚在1.0～100.0mg/L的范围内线性关系良好,r=0.999 7;回收率为90.1%～106.8%(n=3);方法的检测限为0.5 mg/kg。结论本法灵敏度高、简便、易行,结果准确可靠,可为油炸食品的质量控制提供依据。     

Effect of food surface roughness on oil uptake by deep-fat fried products

The aim of this work is to examine the relationship between surface roughness and oil uptake in fried fabricated products. Two product categories were studied, using formulations based either on potato flakes or wheat gluten. Products were deep-fat fried at 170 °C and two oil fractions, penetrated oil and surface oil, were determined at the beginning and at the end of cooling period. The surface of fried products was measured using a scanning laser microscope and characterized by an area-scale fractal analysis. Within each product category, products with higher surface roughness retained more oil. However, this relationship could not be extended when comparing products of different categories. Potato-flake-based products were rougher than gluten-based products, but retained less oil. Further, gluten-based products absorbed most of the oil during frying, whereas potato-flake-based mostly absorbed oil during cooling. Certainly, surface roughness is a key factor in oil absorption, but other food-related properties, such as the micro-structure of the crust, may explain differences among product categories and should be examined in future studies.     

GC-MS测定薯类油炸食品及洋快餐中丙烯酰胺

利用中国疾病预防控制中心营养与食品安全所的样品前处理方法,采用气相色谱和四级杆一级质谱联用技术对薯类油炸食品及洋快餐两类8种食品中丙烯酰胺进行了测定,以相对保留时间和丙烯酰胺相应监测离子的丰度进行定性分析。结果表明,丙烯酰胺标准各浓度水平的相对响应因子RRF的相对标准偏差(RSD)小于20%,满足内标法计算要求,薯类油炸食品丙烯酰胺含量为456～5269μg/kg,洋快餐食品中丙烯酰胺含量为147～214μg/kg。     

边滤对棕榈油煎炸品质的影响

分析了过滤过程中添加滤油粉对棕榈油煎炸品质的影响。实验表明,滤油粉可使深度煎炸的油脂透光率明显升高,能在一定程度上延长棕榈油的氧化稳定时间;在煎炸过程中适当使用滤油粉,可在一定程度上延长棕榈油的使用时间;但滤油粉不能使深度煎炸的棕榈油品质发生显著的改变。     

真空法降低油炸制品含油量

以圆柱形土豆条为研究对象,对油炸和冷却过程中样品表面和内部温度、水蒸气压力以及不同阶段吸油量变化规律进行测量与分析,发现油炸过程中由于水蒸气持续从多孔壳层逸出,阻碍了油进入食品中,土豆样品中70%左右油是在冷却阶段进入食品壳层中的,而且导致吸油的动力--蒸汽冷凝形成的壳层内外压差对环境气压很敏感。在油炸样品冷却阶段,将油炸土豆条置于不同真空环境进行冷却,发现绝对压力80kPa的条件下冷却时,总吸油率从40%降至13.6%,说明冷却过程的真空条件能降低壳层内、外压差驱动力,有效促进表面附着油滴落,阻碍其被吸入食品结构中,从而降低油含量。     

油炸食品中反式脂肪酸的研究

对几种油炸食品中的反式脂肪酸进行研究,采用氯仿-甲醇提取脂肪,甲醇钠甲基化脂肪酸,再通过薄层层析纯化甲酯,用气相色谱检测其中脂肪酸的含量。实验发现,油炸后食品中饱和脂肪酸和反式脂肪酸含量比油炸前食品中含量有升高,而油炸后食品中多不饱和脂肪酸和顺式脂肪酸含量比油炸前食品中含量显著降低。     

煎炸老油对小鼠耐缺氧能力与抗疲劳能力的影响

新鲜精炼菜籽油煎炸薯条3 d(60锅),检测煎炸过程中菜籽油的过氧化值、黏度和极性化合物含量,将煎炸老油按低(10 mL/(kg·d))、中(20 mL/(kg·d))、高(40 mL/(kg·d))剂量对小鼠进行灌胃,另设阴性对照组(10 mL/(kg·d)新鲜精炼菜籽油灌胃)和正常对照组(10mL/(kg·d)蒸馏水灌胃),灌胃4周后,测定各组小鼠体重、耐缺氧生存时间和游泳力竭时间,考察煎炸老油对小鼠耐缺氧能力与抗疲劳能力的影响。结果表明:新鲜精炼菜籽油经过反复煎炸后,随着煎炸时间的延长菜籽油的过氧化值先升高后降低,黏度和极性化合物含量升高,油脂品质发生劣变;各组小鼠的体重没有显著差异;阴性对照组与正常对照组在各个指标上都没有显著差异;与阴性对照组相比,低剂量组小鼠耐缺氧生存时间和游泳力竭时间都没有显著差异,而中、高剂量组小鼠耐缺氧生存时间和游泳力竭时间都显著下降(p 0. 05)。     

煎炸油净化助滤剂在油炸鸡块生产中的应用

综述了煎炸油净化助滤剂脱除煎炸油中的游离脂肪酸、色素、极性化合物等杂质的吸附处理性能,以及其在油炸鸡块生产中的应用。经过滤处理后的煎炸油色泽浅黄,酸价由1．12mgKOH／g降低到0．12mgKOH/g,同时除掉70％以上的色素和大部分极性物,无异味,不再起泡冒烟,过滤净化效果显著。     

油炸食品吸油率控制机理的研究

论述了关于对油炸马铃薯片的工艺过程和工艺参数的研究,并且通过 L9(34)正交试验,找到了最佳工艺条件：油炸时间 4min;厚度 6mm、水分含量 75％、用 10％食盐水前处理。在研究油炸机理和主要影响因素的基础上,提出了控制油炸食品吸油率的新方法。     

Effect of turanose on the rheology and oil uptake of instant fried noodles

Effects of turanose on the functional properties of instant fried noodles were assessed mainly in terms of rheology- and oil uptake-related characteristics. The Mixolab results showed that the water absorption of dough decreased as the turanose level increased, whereas the gel stability and starch retrogradation increased. Also, the use of turanose lowered the storage and loss moduli of the dough, showing a more viscous nature. These viscoelastic characteristics were correlated with the decreased resistance to extension and increased extensibility. NMR spin–spin relaxation analysis showed three distinct water populations in the turanose noodle doughs whose relaxation times were varied depending on the level of turanose. After frying, the noodles with turanose exhibited a continuous and smooth surface as well as a less porous structure. These microstructural characteristics were correlated with the reduced oil uptake by 20.8%, the enhanced oxidative stability and furthermore the improved breaking stress.     

Acceptability of diets containing olive oil fried sardines (Sardina pilchardus) in the prevention of dietary hypercholesterolaemia in rats

Garlic (Allium sativum L) bulb explants produced undifferentiated white globular callus when grown on MS medium having 2,4-dichlorophenoxy-acetic acid (2,4-D) and Kinetin (Kn). Such callus when grown on medium having indole-3-yl-acetic acid (IAA) and/or Kn developed into the differentiating callus which had comparatively more allicin than that of undifferentiated callus. The effect of sucrose, NH/NO ratios and hormone concentrations on growth and allicin development in the callus was investigated. There was a significant increase in allicin development in callus when grown for up to 4 weeks on medium (a) having sucrose at 3% and 5% levels; (b) having NH and NO ratios at 2:1 and 1;1; and (c) with Kn alone at a concentration of 0.5 mg litre^?1, which produced a tenfold increase in allicin content.