煎炸过程对棕榈油品质及南美白对虾中 AGEs含量的影响

以煎炸油和煎炸南美白对虾为研究对象,探究煎炸时间及煎炸物料对煎炸油品质的影响;采用液相色谱-质谱联用及荧光技术测定煎炸对虾中晚期糖基化终末产物（AGEs）的含量,探究煎炸过程对煎炸对虾中AGEs生成的影响。结果表明,高温煎炸可加速棕榈油氧化,使其酸值（AV）、p-茴香胺值（p-AnV）、羰基值（CV）显著增加,24 h时达到最大值。煎炸后,对虾水分含量显著降低,脂肪、丙二醛和荧光AGEs含量显著升高,煎炸批次对其无显著影响。煎炸对虾外层丙二醛、荧光AGEs、非荧光AGEs（羧甲基赖氨酸（CML）、羧乙基赖氨酸（CEL）和甲基乙二醛氢咪唑酮（MG-H1））含量显著高于内部,与未煎炸生虾相比除内部CEL含量有所降低外其余均高于未煎炸生虾。随着煎炸批次的增加,煎炸对虾外层CML、CEL和MG-H1含量均逐渐降低,在煎炸第5批时趋于稳定,煎炸第1批时取得最大值,分别为25.37、335.68 mg/kg和468.20 mg/kg,分别为未煎炸生虾的7、4.5倍和16.5倍;煎炸对虾内部CML、CEL和MG-H1含量均先升高后降低,在煎炸第5批时趋于稳定,煎炸第3批时取得最大值,分别为12.56、85.27 mg/kg和204.20 mg/kg,分别为未煎炸生虾的3.5、1倍和7倍。     

不同煎炸食材对高油酸菜籽油煎炸稳定性的影响

为研究高油酸菜籽油作为煎炸油的潜力,使用高油酸菜籽油煎炸土豆、鸡柳和豆腐3种不同食材18 h,分析煎炸过程中油样的总极性组分含量、酸值、过氧化值、碘值和脂肪酸组成的变化,并对煎炸食品进行了吸油率测定和感官评价,研究煎炸食材对高油酸菜籽油煎炸稳定性的影响。结果表明：3种食材对高油酸菜籽油总极性组分含量、酸值、过氧化值和碘值影响大小顺序均为土豆>鸡柳>豆腐;煎炸18 h时,3组高油酸菜籽油的单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)含量降低,而饱和脂肪酸(SFA)含量增加,其中煎炸土豆的高油酸菜籽油PUFA含量降幅最大,煎炸鸡柳的高油酸菜籽SFA含量增幅最大;煎炸3 h,3种食材感官评分分别达到了9.32、924分和9.12分,之后随着煎炸时间的延长感官评分降低,但豆腐的降幅最小。综上,结合豆腐水分含量高的特性,推测高油酸菜籽油更适合用于高水分含量食材的煎炸,且最佳煎炸时间应控制在3 h之内。     

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...     

煎炸草鱼鱼块的电导率与品质变化相关性研究

为探究煎炸草鱼鱼块的电导率与品质变化的相关性。利用LCR阻抗测试仪测定100 kHz下煎炸草鱼鱼片的电导率与电流方向的影响研究;测量煎炸过程中草鱼鱼块的水分含量、油含量、色泽与质构等品质变化,并与导电率进行拟合。结果表明,电流方向与鱼体平行时的电导率大于电流方向与鱼体交叉时的电导率(最大差异值为0.15 S/m);鱼片中膜的存在导致不同电流方向上鱼片电导率的不同;随着煎炸时间的增加((180±2)℃,0~4 min),草鱼鱼块的电导率、水分含量、亮度值下降,含油量、红度值和黄度值、硬度和咀嚼性升高;煎炸草鱼鱼块的电导率变化与鱼块的水分含量、油含量、色泽与质构变化均呈一定的相关性,相关系数均大于0.95。电导率测量方法对检测草鱼鱼片煎炸过程中的品质变化具有可行性,为煎炸草鱼鱼片的通电加热等新型加工方法的应用和淡水鱼制品的精深加工等方面提供基础数据和理论依据。     

油脂饱和度对油炸马铃薯片品质的影响

以玉米油、花生油、大豆油、大豆棕榈调和油、棕榈油5种不同饱和度油脂作为煎炸用油,以马铃薯片为煎炸内容物,于140℃循环煎炸。考察马铃薯片的油脂含量、水分含量、色泽、酥脆性以及感官评分的变化,综合分析油脂饱和度对油炸马铃薯片品质的影响。结果表明:煎炸油脂的饱和度显著影响油炸马铃薯片的品质(p 0.05),随着煎炸油脂饱和度的增加,油炸马铃薯片的油脂含量呈降低的趋势,水分含量呈增加的趋势,L值呈增大的趋势,表明马铃薯片颜色随着煎炸油脂饱和度的增加而越发鲜亮;油炸马铃薯片的酥脆性、感官评分亦随煎炸油脂饱和度的增加呈显著增加的趋势(p 0.05)。由此可知,相对于不饱和度较高的玉米油、花生油、大豆油,饱和度较高的棕榈油更加适合马铃薯片的煎炸。     

3种食用油在薯条煎炸过程中的品质变化

以大豆油、葵花籽油、棕榈油为研究对象,探讨在(180±5)℃条件下煎炸薯条,每天连续煎炸4h,共煎炸5d后各食用油理化指标的变化。结果表明:随着煎炸时间延长,3种食用油的色泽加深、黏度增加;酸价(AV)显著增加,但未超过国家标准;碘价(IV)则随着煎炸过程进行而逐步降低;过氧化值(POV)在煎炸过程中均先上升后下降,其中大豆油和葵花籽油的POV呈波动性;煎炸3d后,大豆油、葵花籽油的羰基值(CV)超过或非常接近国家标准50meq O2/kg,煎炸4d后,两种油的极性化合物(TPM)含量超过国家标准;整个煎炸过程中棕榈油的CV和TPM含量均低于大豆油和葵花籽油。     

马铃薯煎炸过程中食用油稳定性的研究

采用马铃薯作为食材,菜籽油、胡麻油和米糠油3种常用食用油作为煎炸用油,测定不同煎炸温度、不同煎炸时间下3种食用油酸值、碘值、过氧化值,评价不同食用油煎炸过程中的稳定性。结果表明:经过5 h的连续加热,3种食用油的酸值、过氧化值含量都随加热温度和加热时间的增大有逐渐上升的趋势,碘值随着加热温度和加热时间的增大逐渐下降,3种食用油在125℃、150℃、175℃、200℃温度梯度下连续加热5 h后的酸值均低于5 mg/g。依据过氧化值含量的增加幅度和碘值的降低幅度来评判煎炸油的煎炸品质结果为:胡麻油>菜籽油>米糠油。     

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。     

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。     

冷榨芝麻油在煎炸过程中的品质变化

根据冷榨芝麻油在煎炸过程中的色泽、酸价、过氧化值、羰基价、极性组分、苯并芘含量、木酚素含量以及脂肪酸组成等指标来判断冷榨芝麻油煎炸过程中的品质变化。煎炸试验表明:煎炸过程中冷榨芝麻油中饱和脂肪酸与单不饱和脂肪酸含量升高,多不饱和脂肪酸含量降低,煎炸24 h反式脂肪酸的含量增大至1.16%,冷榨芝麻油吸光度、酸价、羰基价均不断升高,冷榨芝麻油苯并芘含量基本不变;煎炸18 h时羰基价达到了59.01 meq/kg;17 h后木酚素损失急剧加快,24 h时损失率为33.9%,极性组分由最初的4.2%上升到32%。由于17 h后,总木酚素含量降低较快,且在煎炸18 h时羰基价超过国标限制(≤50 meq/kg),因此,冷榨芝麻油的煎炸寿命约为17 h。     

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.     

Physicochemical Properties Changes of Donuts During Vacuum Frying

Vacuum frying was explored to cook donuts and compared to the conventional atmospheric frying. A temperature of 190°C was used for atmospheric frying. Three vacuum levels (3, 6, and 9 kPa vacuum) with three temperature levels (150, 165, and 180°C) were used for vacuum frying. The effects of initial moisture content (IMC), vacuum level and frying temperature on physicochemical properties, such as moisture loss, oil absorption, and quality were investigated. The properties of fried donuts were significantly affected by IMC. Under vacuum frying, volume and total color changes were affected by frying temperature; and oil uptake was affected by vacuum and frying temperature. Frying temperature and vacuum were not directly related to the final moisture content (MC) of donuts. There was no relationship between MC and fat content of donuts. Donut texture was directly related to the vacuum and frying temperature.     

Vacuum frying as a route to produce novel snacks with desired quality attributes according to new health trends

Consumers look for products that contribute to their wellness and health, however, even health-conscious consumers are not willing to sacrifice organoleptic properties, and intense full-flavor snacks remain an important trend. The objective of this study was to examine most important quality parameters of vacuum (1.92 inHg) and atmospheric-fried carrot, potato, and apple slices to determine specific advantages of vacuum technology. Slices were fried using equivalent thermal driving forces, maintaining a constant difference between oil temperature and the boiling point of water at the working pressure (ΔT = 60 and 80 °C). This resulted in frying temperatures of 160 and 180 °C, and 98 and 118 °C, for atmospheric and vacuum frying, respectively. Vacuum-fried carrot and potato chips absorbed about 50% less oil than atmospheric-fried chips, whereas vacuum-fried apple chips reduced oil absorption by 25%. Total carotenoids and ascorbic acid (AA) were greatly preserved during vacuum frying. Carrot chips vacuum fried at 98 °C retained about 90% of total carotenoids, whereas potato and apple slices vacuum fried at 98 °C, preserved around 95% of their initial AA content. Interestingly, results showed that the antioxidant capacity of chips may be related to both the presence of natural antioxidants and brown pigments developed at elevated temperatures. PRACTICAL APPLICATION: A way to reduce detrimental effects of deep-fat frying is through operating-pressure reduction, the essence behind vacuum deep-fat frying. In this way, it is possible to remove product moisture at a low temperature in a low-oxygen environment. The objective of this research was to study the effect of oil temperature reduction when vacuum frying traditional (potatoes) and nontraditional products (carrots and apples) on most important quality attributes (vitamins, color, and oil uptake). Results are promising and show that vacuum frying can be an alternative to produce nutritious and novel snacks with desired quality attributes, since vitamins and color were greatly preserved and oil absorption could be substantially reduced.     

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.     

真空油炸胡萝卜脆片基本特性的研究

真空油炸技术可用于生产高品质的果蔬脆片．主要研究了油炸温度和真空度对胡萝卜片水分质量分数、脂肪质量分数、色泽及质构的影响．试验表明：随着油炸温度和真空度的升高，其干燥和脂肪吸收速度相应提高，且两者呈一定的相关性．统计分析可知：油炸温度和真空度并不显著性影响脆片的白度（L）、红度（a）、黄度（b）值（P〉0．05）；对于脆片的破碎力而言，真空度具有显著性影响（P〈O．05），而油炸温度不具有显著性影响（P〉0．05）．     

Vacuum frying of high-quality fruit and vegetable-based snacks

Sweet potato, green beans, Tommy Atkins mango, and blue potato were fried in a vacuum frying process at a temperature of 120-130 ± 1°C. Before frying, green beans and mango slices were soaked in a 50% maltodextrine 0.15% citric acid solution. The products were also fried in a traditional (atmospheric pressure) fryer at 160-165 ± 1°C for 4 min. A 30-member consumer panel rated the sensory quality of both types of fried snacks using a 1-9 hedonic scale. Compared with traditional frying, oil content of vacuum-fried sweet-potato chips and green beans was 24% and 16% lower, respectively. Blue potato and mango chips had 6% and 5% more oil, respectively, than the traditional-fried samples. Anthocyanin (mg/100 g d.b.) of vacuum-fried blue potato chips was 60% higher. Final total carotenoids (mg/g d.b.) were higher by 18% for green beans, 19% for mango chips, and by 51% for sweet-potato chips. Sensory panelists overwhelmingly preferred (p < 0.05) the vacuum-fried products for color, texture, taste, and overall quality. Most of the products retained or accentuated their original colors when fried under vacuum. The traditional-fried products showed excessive darkening and scorching. These results support the applicability of vacuum frying technology to provide high-quality fruit and vegetable snacks.     

Effects of maltodextrin level,frying temperature and time on the moisture,oil and beta‐carotene contents of vacuum‐fried apricot slices

Response surface methodology was used to investigate the effects of frying temperature, time and maltodextrin (MD) levels on the moisture, oil and beta‐carotene contents of the vacuum‐fried apricot slices. Based on the results, the moisture content of vacuum‐fried apricot slices decreases with increasing frying temperature and frying time. Generally, the oil content of vacuum‐fried apricot slices decreases with decreasing frying temperature and frying time. The beta‐carotene content of vacuum‐fried apricot slices increases with increasing frying temperature. But the trend of increase in the beta‐carotene content of the product with frying temperature was higher at lower MD level. When processing vacuum‐fried apricot slices, a frying temperature of 100 °C, frying time of 72.5 min and an MD level of 70% must be used to achieve a product of acceptable moisture, oil and beta‐carotene contents.     

Comparative study of physical and sensory properties of pre-treated potato slices during vacuum and atmospheric frying

The objective of this research was to study the effect of different processing conditions on physical and sensory properties of potato chips. Potato slices of Desirée and Panda varieties (diameter: 30 mm; thickness: 3 mm) were pre-treated in the following ways: (i) control or unblanched slices without pre-drying; (ii) blanched slices in hot water at 85 °C for 3.5 min and air-dried at 60 °C until a final moisture content of ∼0.6 kg water/kg dry solid; (iii) control slices soaked in a 3.5 kg/m³ sodium metabisulphite solution at 20 °C for 3 min and pH adjusted to 3. Pre-treated slices were fried at 120 and 140 °C under vacuum conditions (5.37 kPa, absolute pressure) and under atmospheric pressure until they reached a final moisture content of ∼1.8 kg water/100 kg (wet basis). An experimental design (3 × 2³) was used to analyze the effect of pre-treatment, potato variety, type of frying and frying temperature over the following responses: oil content, instrumental color and texture and sensory evaluation. Vacuum frying increased significantly (p < 0.05) oil content and decreased instrumental color and textural parameters. Sensory attributes, flavor quality and overall quality, were significantly improved using vacuum frying. The higher frying temperature (140 °C) increased ΔE, maximum breaking force, hardness and crispness and decreased L^* and b^* values. On the other hand, Panda potato variety improved the color of the product. A great improvement on color parameters was obtained using sulphited potato slices instead of the other pre-treatments. Although, the better flavor was obtained for control potato chips, no significant differences were found for overall quality between control and sulphited potato chips. Significant correlations (p < 0.01) between sensory and instrumental responses were found.     

Effects of osmotic pretreatment and frying conditions on quality and storage stability of vacuum-fried pumpkin chips

The effects of osmotic (OP), ultrasound-assisted osmotic pretreatment (UAOP) and frying conditions on quality and storage stability of vacuum fried pumpkin chips were investigated. The pumpkin samples were pretreated in maltodextrin solution and subsequently fried at different temperatures (90–110 °C) and time periods (10–30 min). The results demonstrated that the moisture content, water activity, lightness, yellowness and carotenoid content of the fried chips decreased, while oil content, hardness and a* (dark brown colour) value increased with increasing frying temperature and time. UAOP reduced about 16.0% of oil absorption and enhanced approximately 70% of carotenoid retention in the fried chips. UAOP samples were also more stable during storage than the untreated ones, indicated by lower degradation kinetics constants of key quality parameters. The proposed pretreatment could be an effective method for food industries to develop vacuum fried pumpkin chips with improved quality and stability.     

远红外油炸对鸡肉品质的影响

主要研究了远红外辅助油炸和普通热传导式油炸两种方式对鸡肉油炸品质的影响。实验选用新鲜市售鸡胸肉,油炸温度为(165±2)℃,考察其在70～110s油炸时间段内色泽、质构、中心温度、水分含量、含油量和失重率的变化规律。结果表明:除鸡肉的硬度值外,不同的油炸方式和油炸时间对鸡肉各项测定指标均影响显著(P<0.05)。以普通热传导式油炸为对照,远红外油炸的鸡肉明度(L*)降低,红度(a*)和黄度(b*)增加;硬度值变化不显著,弹性值略有增加;内部的温度上升均匀、波动小;最高含油量降低33%,最大失重率降低10.21%。因此,远红外油炸促进了鸡肉色泽的变化,使内部受热均匀,降低了含油量,减少油炸损失,对油炸品质的提高起到积极作用。