水分含量对马铃薯淀粉凝胶体系脂肪吸收的影响

以马铃薯淀粉为原材料,与水进行模拟,在180 ℃条件下对马铃薯淀粉凝胶样品进行常压油炸,研究油炸样品中总油脂含量,以及各部分油脂含量的分布情况。结果表明：随着水分含量的增加,马铃薯淀粉凝胶体系油炸样品的总油脂含量、表面油脂含量和表面渗透油脂含量呈逐渐增加的趋势。随着油炸时间的延长,马铃薯淀粉凝胶体系油炸样品的总油脂含量和组织结构油脂含量呈逐渐增加的趋势,表面渗透油脂含量呈逐渐降低的趋势。随着水分含量的增加,表面渗透油脂含量在油炸样品总油脂含量中占据最大部分,其次是组织结构油脂含量,最少的是表面油脂含量。不同部分油脂含量的变化呈现一定的规律性,但变化幅度有一定的差异。     

深度油炸过程中油脂劣变对薯条中油脂和水分含量的影响及水分替代规律

为研究马铃薯条对不同油脂的吸收规律,使用深度油炸1、3、5 d后的大豆油、油茶籽油及两种油脂不同比例调和油煎炸马铃薯条,测定马铃薯条在油炸过程中总油脂、表面油脂、结构油脂、水分含量的变化。结果发现:对于同一种油脂来说,马铃薯条中总油脂含量随油炸时间的延长而增加;对于各新鲜油脂处理组马铃薯条,当油炸时间小于150 s时,总油脂含量随油炸时间的延长而明显增加,当油炸时间超过150 s时,总油脂含量随油炸时间的延长变化不明显,油炸240 s后的总油脂含量接近0.22 g/g。油脂劣变程度对油炸马铃薯条的油脂含量有明显影响,对于相同劣变程度的油脂,随油炸时间延长,油脂黏度增大,马铃薯条对油脂吸附能力增强,表现为所有处理组马铃薯条的表面油脂含量的升高。在油炸过程中,当油炸时间小于120 s时,水分含量变化速率随着反复油炸时间的延长而降低;油炸150～240 s时,总油脂含量与水分含量的比值随着油炸时间的延长差异逐渐增加,其中在使用深度油炸3、5 d的油处理时,油茶籽油油炸组最高。     

油炸对马铃薯淀粉特性的影响

本文采用直接油炸淀粉的方法,研究不同油炸温度对马铃薯淀粉结构和性能的影响。采用电子扫描显微镜(SEM)、偏光显微镜、X-射线衍射仪(XRD)、Brabender 粘度仪等对油炸处理后淀粉的颗粒形态、结晶结构、糊化性质、透明度及冻融稳定性等进行测定分析。结果表明,随着油炸温度的升高,马铃薯淀粉的颗粒表面结构发生了明显的变化,淀粉颗粒表面出现凹陷、膨胀和破裂,样品的偏光十字双折射强度减弱,甚至消失;油炸破坏了淀粉的结晶结构,180℃油炸淀粉结构变化最显著,最适于淀粉的消化吸收;随着油炸温度的升高,样品粘度逐渐降低,且峰值粘度小于原淀粉;油炸淀粉的透光率较低,冻融稳定性较差,且均低于原淀粉,油炸淀粉类食品不适于冷冻。     

深度油炸过程煎炸油的氧化及其对油炸外裹糊鱼块品质的影响

目的 探究深度油炸过程煎炸油的氧化,并进一步研究煎炸油氧化对油炸外裹糊鱼块品质的影响。方法 分别采用棕榈油、大豆油、葵花籽油、小麦胚油在150、160、170、180、190℃下油炸外裹糊鱼块,测定煎炸油的酸价、过氧化值、黏度、介电常数以及油炸外裹糊鱼块外壳的水分含量、油脂含量、表面色度。结果 随着油炸温度的升高,煎炸油的游离脂肪酸含量增加,导致煎炸油的酸价、黏度和介电常数升高,过氧化值呈现波动下降的趋势;油炸外裹糊鱼块的水分含量逐渐减少,油脂含量逐渐增加,L*和b*呈递减趋势、a*呈递增趋势,且使用4种煎炸油的各项指标存在明显差异。结论 煎炸油的油炸温度和不饱和脂肪酸含量显著影响了煎炸油的氧化,导致外裹糊鱼块深度油炸过程中水分蒸发和油脂吸收有明显差异,最终影响了油炸外裹糊鱼块的品质。     

香菇脆片真空油炸过程中传质规律

真空油炸过程中传质现象对真空油炸果蔬脆片的品质和安全控制极为重要。研究了油炸温度（80、90、100℃）、真空度（0.075、0.085、0.095 MPa）、预处理方式（漂烫,漂烫+浸渍+涂膜）对香菇脆片真空油炸过程中水分扩散和油脂吸收的影响,结果表明:香菇脆片的含水率随油炸时间的增加而逐渐降低,采用Pabis经验模型能较好模拟香菇脆片真空油炸过程中的水分变化;利用菲克定律建立模型,得到香菇真空油炸的水分有效扩散系数为2.47×10-9~7.70×10-9 m2/s,并且随着油炸温度和真空度的升高而增大;采用浸渍和涂膜处理降低了水分有效扩散系数。香菇片的油脂含量随着油炸时间的增加而逐渐升高,一段时间后达到稳定值;浸渍和涂膜处理降低了真空油炸香菇脆片的含油率。Pabis经验模型能够较好的模拟真空油炸香菇脆片的油脂含量变化,油炸温度和真空度对香菇脆片的平衡含油率（Y_max）影响不大,油脂吸收系数（K_Y）随着油炸温度和真空度的升高而增加。     

不同油炸温度下糯米糕水分及油脂含量分布

本实验以糯米为原料制作糯米糕,在150、160、170、180和190℃的温度下分别油炸6 min,冷却后得糯米糕全糕,并剥离成外壳层、中间层和中心层三部分,通过对比原糯米粉、糯米糕全糕、外壳层、中间层和中心层的水分、油脂含量,研究不同温度下油炸糯米糕中的水分及油脂含量分布。结果表明,与原糯米粉相比,水分含量为:原糯米粉>中心层>全糕>中间层>外壳层,而油脂含量为:外壳层>全糕>中间层>中心层>原糯米粉。低场核磁共振测定表明,结合水含量:原糯米粉>中心层>全糕>中间层>外壳层;油脂含量结果与国标法测定结果一致。油炸温度对油脂含量有一定影响,随着温度升高,外壳层油脂含量呈先上升后下降的趋势,170℃油脂含量最高,为17.63%。油炸糯米糕在不同油炸温度下各部位自由水、结合水与油脂变化趋势相同,实际油炸时可选用150~160℃温度进行。     

油炸温度和时间对外裹糊牡蛎品质的影响

以水分含量、油脂含量、颜色、感官评分和油脂吸收为指标,分别考察了油炸温度(165、175、185℃)和油炸时间(60、90、120、150、180 s)对油炸外裹糊牡蛎品质的影响。结果表明,随着油炸温度的升高和时间的延长,油炸外裹糊牡蛎的水分含量降低,油脂含量增加,L*值和b*值减小、a*值增大,感官评分先升高后下降,油脂吸收程度加大;175℃炸制90 s或120 s所得油炸外裹糊牡蛎色泽金黄,外酥里嫩,牡蛎特征风味突出,感官品质最好。     

物料组成对重组马铃薯片油脂吸收的影响

为了研究物料组成对油炸样品油脂吸收的影响,以不同比例的马铃薯淀粉、谷朊粉、大豆分离蛋白和水为原料制备不同体系的重组马铃薯片,采用染色法测定体系中不同类型的油脂的含量,并利用扫描电镜(SEM)和体视显微镜(SM)观察油炸前后的结构特征。结果表明,重组体系中的蛋白质量分数越高,总油脂和结构油脂含量越低,添加谷朊粉的重组体系比添加大豆分离蛋白体系的总油脂含量低10.04%~16.69%。蛋白质的添加均会影响油炸前后的重组马铃薯片的表面及内部结构,且油脂含量随着蛋白质量分数的增加而降低。     

油炸过程中淡水小龙虾理化性质与品质变化

研究分析油炸工艺（油炸温度（140、160、180、200 ℃）和油炸时间（15、30、45、60 s））对淡水小龙虾（虾壳、虾肉、虾黄）理化性质及品质的影响。测定淡水小龙虾中心温度、油炸损失率、色泽、质构特性、挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、硫代巴比妥酸反应物（thiobarbituric acid reactive substances,TBARs）值以及菌落总数（total plate count,TPC）的变化。结果表明：油炸温度对虾肉中心温度影响不显著,而油炸时间对虾肉中心温度影响显著（P＜0.05）;油炸温度180 ℃、油炸45 s时,虾肉中心温度可达到肌肉熟制标准温度;随着油炸温度升高及油炸时间延长,小龙虾油炸损失率显著上升（P＜0.05）;虾壳、虾肉、虾黄亮度值、红度值均呈上升趋势,而黄度值呈下降趋势;虾肉硬度、回复性、弹性、黏性、咀嚼性均显著增加（P＜0.05）;油炸过程中,虾肉TVB-N含量显著增加（P＜0.05）,但均低于10 mg/100 g,表明虾肉油炸后保持较好的新鲜度;虾肉TBARs值随油炸温度升高、油炸时间延长而增加,其中油炸时间对TBARs值影响较明显;新鲜虾肉初始带菌量非常高,油炸处理后虾肉TPC显著降低（P＜0.05）,油炸时间对虾肉TPC影响不明显。     

薯片在油炸过程中品质变化及其货架期预测

为了探究薯片在油炸过程中品质变化,以不同油炸时间马铃薯片为研究对象,测定马铃薯片的品质变化,观察其微观结构并对马铃薯片货架期进行预测。结果表明:随油炸时间的延长,马铃薯片的水分含量降低,含油率升高,脆度变化较大;马铃薯片表面淀粉颗粒糊化逐渐形成凸起和空隙,由于外皮壳的保护作用,空隙先在横断面中出现,薯片内部空隙多于其表面;通过比较脱脂前后薯片,表明薯片与煎炸油之间以物理作用为主;随着薯片贮藏时间的延长,薯片中油脂的酸值、过氧化值和羰基值逐渐增大,根据Arrhenius方程预测薯片在20℃的货架期约为102d。     

Development of Healthy Low-Fat Snacks: Understanding the Mechanisms of Quality Changes During Atmospheric and Vacuum Frying

Excess consumption of fat, a main component in fried food, is a key dietary contributor to coronary heart disease and perhaps some types of cancer. Although consumers are interested in healthier snacks, they are not willing to sacrifice organoleptic properties. Vacuum frying might be an alternative for the production of nutritious, healthy, palatable, and novel snacks. The objective of this review is to discuss the effect of atmospheric deep-fat frying on the main microstructural components and quality parameters of fried food, to understand how quality can be improved by lowering the operating pressure and, therefore, the processing temperature.     

荤素分类煎炸对油脂品质的影响

为了延长煎炸油的使用寿命,有效降低成本,研究了荤素分类煎炸对油脂品质的影响。采用食材荤素分类及不分类煎炸并循环使用煎炸油,分析了两种煎炸方式下煎炸油的色泽、酸值、过氧化值、p-茴香胺值、极性组分含量的变化情况,并对比分析两种煎炸方式用油量。结果表明：采用荤素分类煎炸可以更好地抑制油脂色泽、酸值、p-茴香胺值及极性组分含量的增长速度;不分类煎炸油脂的色泽在煎炸2 d后无法用比色仪检测,分类煎炸7 d后油脂的色泽才接近不分类煎炸2 d的色泽;不分类煎炸的油脂酸值(KOH)在煎炸前3 d内急剧上升,由初始的0.09 mg/g增至1.30 mg/g,分类煎炸的油脂酸值(KOH)浮动较小,由初始的0.09 mg/g最高增加至0.62 mg/g;在煎炸7 d时,不分类煎炸的油脂p-茴香胺值由初始的4.0增加到38.0,分类煎炸的油脂p-茴香胺值由初始的4.0增加到15.0,不分类煎炸油脂的p-茴香胺值的增长速度是分类煎炸的近3倍;不分类煎炸,油脂极性组分含量在第1天内急剧上升,在第4天达到最高,为12.5%,后逐渐趋于平稳,分类煎炸,油脂极性组分含量在前3 d内均保持在8%左右,之后才有上升的趋势...     

Reviewing the effects of vacuum frying on frying medium and fried foods properties

Vacuum frying (VF) is a process developed at a pressure lower than atmospheric pressure, in which lower temperatures are employed to remove moisture from the food and reduce the oil content in the final product. Diverse studies have been published for VF or assisted with microwave and ultrasound, facing the challenges of accomplishing the physical and sensory properties appreciated in fried products. The studied matrices under VF include mainly vegetable origin foods (apple, banana, carrot, donuts, kiwi, mushroom, pea, pear, potato and sweet potato) and some animal origin products (chicken nuggets, fish fillets and surimi products). This review aimed to show recent and relevant findings of the application of VF, analysing both the effects on the frying medium and the impact on the fried foods. The inclusion of microwave and ultrasound technologies aids in the obtention of high-quality products in terms of sensory and textural attributes, oil content as well as reduced oil degradation. This technique may provide safer and stable fried foods with lower oil content aiding in improving the diet of consumers and reducing production costs.     

Frying Process: From Conventional to Air Frying Technology

ABSTRACT

Studies have shown that products resulting from oils heated for long periods under high temperatures contain polar compounds such as polymers, dimers, free fatty acids, and acrylamide, which lead to metabolic changes, malabsorption of essential fat, and development of cancer. The air frying process is capable of reaching the characteristic color and similar flavor obtained by deep fat frying, and reduces the amount of oil content and polar compounds. However, it has not been extensively studied and should receive a greater focus on the detailed evaluation of components and properties of foods and the effects on the human health.     

高油酸菜籽煎炸油的研究

研究开发以精炼高油酸菜籽油为基油的煎炸专用油,设计合理的煎炸油配方。根据棕榈油、棉籽油、高油酸菜籽油等常用煎炸油的煎炸特性、脂肪酸组成及最终产品的质量要求,得到了油酸含量高于45%、亚麻酸含量低于4%、多不饱和脂肪酸含量低于30%的配方油,并通过方程运算和预实验,得到最佳配方为高油酸菜籽油、24度棕榈油、棉籽油质量比范围50%～64%∶0%～36%∶0%～24%。通过计算机筛选出5种配方油,其中配方油5 (高油酸菜籽油与24度棕榈油质量比为64∶36)煎炸稳定性好,煎炸寿命长,油炸食品感官效果好,因而是煎炸配方油的最佳选择。     

煎炸薯条条件对高油酸葵花籽油中饱和型甘油酯核心醛生成的影响

为对煎炸过程中甘油酯核心醛(GCAs)的调控提供指导,以高油酸葵花籽油煎炸薯条实验为例,探讨煎炸方式、频次、温度以及油料比对煎炸过程中9-氧代壬酸酰基甘油三酯(9-oxo)、8-氧代辛酸酰基甘油三酯(8-oxo)两种饱和型GCAs生成的影响。结果表明：间歇煎炸较连续煎炸更易导致GCAs的生成;每小时煎炸1批次薯条所产生的饱和型GCAs低于每小时煎炸2批次和4批次的;随着煎炸温度的降低,两种饱和型GCAs含量均减少;油料比为10∶1时,两种饱和型GCAs含量整体较低。综上,为控制饱和型GCAs的生成,需采用连续煎炸方式,尽量降低煎炸温度和煎炸频次,控制油料比为10∶1。     

不同煎炸食材对米糠油煎炸品质影响的研究

利用米糠油对不同煎炸食材进行间歇性煎炸,通过对煎炸油色泽、酸值、羰基值、脂肪酸组成、反式脂肪酸含量、维生素E含量的检测分析,对比研究植物淀粉基食材(薯条)、高含水量食材(豆腐)、肉类食材(鸡翅)、面粉基食材(油条)4种代表性煎炸食材对煎炸油品质的影响。结果表明:不同煎炸食材因所含主要组分的不同,对煎炸油品质劣变呈现出不同程度的影响;煎炸油酸值增大程度依次为豆腐鸡翅油条薯条;羰基值增大程度依次为油条薯条豆腐鸡翅;总反式脂肪酸增大程度依次为油条鸡翅薯条=豆腐;维生素E含量降低程度依次为薯条油条鸡翅豆腐。     

Provenance of the oil in par-fried French fries after finish frying

Frozen par-fried French fries are finish-fried either by using the same type of oil used for par frying, or a different type. The nutritive quality of the final oil contained in the product depends on the relative amounts and the fatty acid (FA) composition of the oils used for par frying and finish frying. With the aim of understanding the provenance of the oil in the final product, par-fried French fries-either purchased ready or prepared in the laboratory-were finish fried in oils different from the ones used for par frying. The moisture content, oil content, and FA compositions of the par-fried and finish-fried products were experimentally determined, and the relative amounts of each of the oils present in the final product were calculated using the FAs as markers and undertaking a mass balance on each component FA. The results demonstrate that 89% to 93% of the total oil in the final product originates from the finish-frying step. The study also shows that a significant proportion of the oil absorbed during par frying is expelled from the product during finish frying. Further, the expulsion of par-frying oil was found to occur in the early stages of the finish-frying step. Experiments involving different combinations of par-frying and finish-frying oils showed that the relative proportions of the 2 oils did not depend on the individual fatty acid profiles. This study concludes that any positive health benefits of using an oil having a favorable FA profile for par frying, can potentially be lost, if the oil used for finish frying has a less favorable composition. PRACTICAL APPLICATION: This paper estimates the relative amounts of oil in French fries that have been fried in 2 stages-a par-frying step and a finish-frying step-which is commonly practiced in food service establishments as well as homes. The 2 key conclusions are: (1) nearly 90% of the oil content of the final product is the one used for finish frying; that is, a processor may use very good oil for par frying but if the oil used for finish frying is inferior, its effect will dominate. (2) The paper also shows that a significant proportion of the oil used by the processor gets expelled during finish frying.     

Comparison between atmospheric and vacuum frying of apple slices

Vacuum deep-fat frying is a new technology that can be used to improve quality attributes of fried food because of the low temperatures employed and minimal exposure to oxygen. In this paper atmospheric and vacuum frying of apple slices were compared, in terms of oil uptake, moisture loss and color development. In addition, some apple slices were pre-dried (up to 64% w.b.) before vacuum frying to determine the overall effect. To carry out appropriate comparisons between both technologies equivalent thermal driving forces were used in both processes (ΔT = 40, 50, 60 °C), keeping a constant difference between the oil temperature and the boiling point of water at the working pressure. Vacuum frying was shown to be a promising technique that can be used to reduce oil content in fried apple slices while preserving the color of the product. Particularly, drying prior to vacuum frying was shown to give the best results. For instance, when using a driving force of ΔT = 60 °C, pre-dried vacuum fried slices absorbed less than 50% of the oil absorbed by atmospheric fried ones. Interestingly, a strong relationship between water loss and oil content was observed in both technologies, allowing the extension of observations that have been made for atmospheric frying.     

一种快速评价煎炸油稳定性方法的建立

用于评价煎炸油稳定性的传统方法不能如实反映实际煎炸过程中的变化,为了快速可靠地模拟实际煎炸过程中油脂的劣变情况,将以淀粉、葡萄糖、硅胶(质量比4∶1∶1)为原料制备的配方食物加入(180±5)℃的大豆油中,在自制快速煎炸装置中以500 r/min的搅拌速度进行煎炸试验,测定煎炸油极性物质含量的变化。通过分析快速煎炸和实际煎炸中极性物质的含量及其组成变化,确立两者之间的联系。结果表明,所建立的快速煎炸方法操作简便、耗时短,与实际煎炸中油脂劣变程度有良好的一致性,可应用于快速评估煎炸体系中油脂的稳定性。