煎炸过程中油脂劣变的影响因素研究

分别对煎炸时间、煎炸方式、煎炸温度、煎炸食材及煎炸油种类对煎炸油极性组分含量和酸值的影响进行研究,分析控制煎炸过程中油脂劣变的有效措施。结果表明：煎炸油的极性组分含量、酸值随煎炸时间的延长而升高,且连续性煎炸优于间歇性煎炸;煎炸温度越高,油脂劣变速度越快,油脂的极性组分含量、酸值升高越快,为保证煎炸食品的卫生质量,延长煎炸油的使用寿命,控制煎炸温度低于200 ℃;不同煎炸食材对煎炸油品质劣变速度的影响大小依次为鱼饼>鸡腿排>薯条;不同煎炸油在煎炸过程中极性组分含量、酸值的变化均不同,多不饱和脂肪酸含量高的大豆油比稻米油、棕榈油更容易发生水解和氧化,稻米油的煎炸周期接近棕榈油。     

氧化甘三酯指标在煎炸油品质评价中的应用（网络首发、推荐阅读）

研究煎炸过程油脂各极性组分的变化规律,并从法定废弃点处极性物质组成及指标间相关性两个角度,评价各极性组分指标用于表征油脂煎炸废弃的可行性。煎炸过程,油脂劣变生成的总极性组分(TPC)随煎炸时间的延长而累积。在油脂法定废弃点处,当TPC为27%时,煎炸油脂含11.2%的氧化甘油三酯多聚物+氧化甘油三酯二聚物(oxTGO+oxTGD),与各国标准规定的TPC和ox TGO+oxTGD比例是接近的。当TPC为27%时,煎炸油脂的氧化甘油三酯单体(ox TGM)含量为3.5%,煎炸过程oxTGM含量变化呈上下波动而无明显规律。Pearson相关性分析表明,煎炸过程油脂oxTGM与TPC无显著相关(P>0.05),表明应用TPC评价煎炸油品质时,实际未能同时覆盖对oxTGM的有效控制。因此须用TPC和oxTGM两项指标方可评价油脂煎炸过程的劣变。考虑到oxTGM的潜在毒性最强,oxTGM值作为表征高温煎炸油脂氧化劣变的废弃指标有一定实际意义。     

不同煎炸温度下亚麻籽油中α-亚麻酸的反式异构化及其分布情况

在170 ℃和200 ℃下进行亚麻籽油煎炸薯条研究,比较不同温度煎炸过程中α-亚麻酸的反式异构化情况及α-亚麻酸反式异构体在煎炸油和煎炸薯条中的分布情况,并探究了α-亚麻酸反式异构体含量与其他油脂劣变指标(酸价、过氧化值、p-茴香胺值,总极性物质含量)的相关性。结果表明：煎炸使煎炸油中α-亚麻酸反式异构体含量显著增加（p<0.05）,200 ℃煎炸温度下的增加趋势更明显,且温度是主要影响因素;煎炸薯条油脂的α-亚麻酸反式异构体含量小于煎炸油的,且170 ℃较200 ℃差异更显著;煎炸亚麻籽油中的α-亚麻酸反式异构体含量与酸价、总极性物质含量成显著正相关,且与前者的相关性更强,说明α-亚麻酸反式异构体的生成与煎炸油品质劣变有关,尤其是水解反应。     

植物油脂在深度煎炸过程的品质控制

煎炸油在煎炸过程中的变化,即煎炸食发生脱水过程,油脂在深度煎炸过程中发生氧化反应、聚合反应和水解反应。掌握煎炸油周转期、煎炸油重要特性指标如极性物质总值(TPM值)。控制煎炸油和煎炸食物的质量。     

5种精制食用油在煎炸薯条过程中的品质变化

以大豆油、菜籽油、棕榈液油、棉籽油和煎炸调和油为研究对象,以薯条为煎炸原料,通过研究5种精制食用油在高温煎炸过程中理化指标的变化,从而反映出不同精制食用油在煎炸过程中品质的变化。结果表明:色泽可以作为一个最直观的指标反映食用油的煎炸程度;用酸值来评价煎炸油的品质具有滞后性和多变性;过氧化值的高低并不能完全反映油脂的煎炸程度,仅可作为判断食用油煎炸品质的参考指标;羰基值随着煎炸时间的延长整体呈线性正相关趋势,说明羰基值是一个判断煎炸油热劣变程度的灵敏指标;5种精制食用油一旦经过煎炸,氧化诱导时间迅速缩短,与油脂的煎炸程度没有很好的相关性,因此氧化诱导时间不能作为评价油脂煎炸品质的可靠指标;极性组分的含量是评价煎炸油热劣变程度的可靠手段之一。在煎炸过程中,棕榈液油的煎炸稳定性明显高于其他4种食用油。     

大豆油煎炸过程极性组分和非极性组分中脂肪酸组成的研究

通过柱层析法分离煎炸油的极性组分和非极性组分,采用GC-MS分析两种组分中的脂肪酸组成及含量。结果表明:煎炸油极性组分和非极性组分具有相似的脂肪酸组成及相对含量,且两种组分间饱和脂肪酸(SFA)、不饱和脂肪酸(UFA)、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)呈极显著相关(r0.90,p0.01)。极性组分中cis C18∶2含量相对较高;非极性组分中cis C18∶2/C16∶0比值减小程度明显大于极性组分,则非极性组分的cis C18∶2在生成极性基团时反应最为剧烈。煎炸油中极性物质含量随煎炸时间延长而增多,其中极性组分中总脂肪酸含量呈梯度增加趋势,并与煎炸油中总极性物质(TPC)含量呈极显著相关(p0.01);非极性组分中总脂肪酸含量显著减少,表明在煎炸过程中各种甘油三酯均参与反应,导致含有极性基团的脂肪酸含量不断增加,其中cis C18∶2组成与极性组分含量变化密切相关。按极性大小将复杂的煎炸油成分进行分类研究,有利于对大豆油煎炸过程中的复杂组分进行全面分析,为得到脂肪酸组成与极性组分含量变化的关系和提出煎炸油寿命的建议提供更为可靠的数据。     

电导率法快速检测煎炸油极性组分含量的研究

以大豆油、棕榈油和米糠油为煎炸用油,在(190±5)℃的煎炸温度下进行32 h连续煎炸油条试验,通过对不同煎炸时间所取煎炸油样极性组分含量和电导率值的测定以及两者之间对应关系的对比分析,研究电导率法在快速检测煎炸油中极性组分含量方面的应用。结果表明,大豆油、棕榈油和米糠油的极性组分含量均随煎炸时间的延长而增大;电导率值随煎炸时间的延长呈波动变化,整体呈增大趋势;极性组分含量和电导率值之间无显著线性关系。因此,电导率法可用于油脂是否经过煎炸的快速鉴别及煎炸程度的初步鉴别,但能否应用于煎炸油中极性组分含量的快速测定或应用电导率值表示极性组分含量还需进一步深入研究,同时应对电导率值测定方法进行完善和规范。     

气相色谱-质谱联用结合化学计量学分析棕榈油煎炸过程中化学成分的变化

为了探究棕榈油在煎炸过程中化学成分的变化与极性组分之间的相关性,采用气相色谱-质谱联用技术获取了不同煎炸时间煎炸油的化学成分信息,结合化学计量学软件进行数据筛选、主成分分析与聚类分析。结果表明：经过筛选后的数据,不同煎炸时间煎炸油在主成分得分图上区分明显;聚类分析可将煎炸不同时间的煎炸油分成三类,每类之间化学成分差异明显,其中过度煎炸组极性组分含量基本大于27%;初步鉴别出9种煎炸过程中产生的差异性化合物,这些化合物的含量变化均与极性组分含量呈明显的线性关系（R2＞0.95）。研究表明,煎炸油在煎炸过程中化学成分会发生变化,部分变化与极性组分含量呈线性相关,极性组分含量可以作为评判煎炸油劣变程度的有效依据。     

三种煎炸食品中油脂极性组分的研究

根据<食品中油脂的极性组分(PC)的测定>(GB/T5009.202-2003)方法和相关国家标准,就煎炸食品可能有的食用安全问题,对三种煎炸食品进行摸拟试验与检验分析研究.并对使用的植物油在煎炸前、煎炸后极性组分含量以及在煎炸食品中的油脂极性组分含量变化进行比较.说明煎炸食品中极性组分含量随煎炸时间的增加变化,并且与添加新油有关.通过水分、脂肪含量的测定,了解了煎炸食品在煎炸过程中油脂劣变状况.     

油炸豆制品中极性组分含量的检测研究

豆制品含有丰富的蛋白质,经高温油炸后,香气宜人,色泽金黄,但在煎炸过程中会产生极性物质。选取上海市三家企业的不同油炸豆制品,研究油炸豆制品中油脂极性组分含量。采用制备型快速柱层析法进行极性组分的检测,并对油炸豆制品中水分含量、油脂含量、油脂极性组分含量以及对应的煎炸油中极性组分含量进行同步测定。结果表明:油炸豆制品中水分含量、油脂含量及油脂极性组分含量与油炸豆制品的生产工艺有关;油炸豆制品中油脂极性组分含量与其煎炸油中极性组分含量相对应;三家企业的三种油炸豆制品中油脂极性组分含量均低于国家限定标准27%,但仍应及时对煎炸油进行净化和更新。     

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.     

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...     

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。     

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.     

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。     

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.     

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。