French Fries oleuropein content during the successive deep frying in oils enriched with an olive leaf extract

Olive oil, sunflower oil and soybean oil were enriched with an olive (Olea Europaea) leaf extract rich in oleuropein at a supplementation level of 100 mg total phenolics per kg oil. Supplemented oils were used for deep frying of potatoes for eight successive frying sessions without replenishment under domestic frying conditions. Supplemented oils contained oleuropein while deep frying resulted in a gradual decrease in oils oleuropein content. After the eighth successive frying, oleuropein was still detected in oils, its retention being 3.2–12.4%. Deep frying of potatoes in supplemented oils succeeded in preparing French fries containing oleuropein even after eight successive fryings. Contrary to the oil type, the number of frying sessions affected potatoes oleuropein content. Oleuropein intake by consuming French fries deep‐fried in enriched oils was approximately ten times higher in potatoes prepared in the first frying session as compared to the respective intake after the eighth frying.     

Effects of diets containing oils from repeated frying on magnesium absorption

Olive oil, sunflower oil and palm olein were used in repeated potato fryings until the oils reached the limit of 25% of polar compounds allowed by law. Six groups of rats, over 28 days, were fed diets containing 8% of: olive oil; olive oil from 69 fryings; sunflower oil; sunflower oil from 48 frying; palm olein, and palm olein from 80 fryings. Body weight and food intake were monitored weekly, during days 21–28 faeces and urine were collected and finally blood and carcasses were also collected and stored. No significant differences were observed in food intake and body weight among the six groups of animals. The type of oil did not modify magnesium intake, the urinary and faecal excretion of this mineral nor its apparent absorption or retention. The consumption of oils from frying, however, induced an increase in apparent magnesium absorption due to a decrease in faecal magnesium excretion, but magnesium retention did not vary owing to the increase in urinary losses. Serum magnesium and magnesium contents and concentrations in carcasses were unaffected. Therefore, it was concluded that the consumption of used frying oils enhances magnesium absorption, independently from the type of oil, although magnesium retention is not affected due to a an elevation of urinary excretion. © 1999 Society of Chemical Industry     

Use crude olive leaf juice as a natural antioxidant for the stability of sunflower oil during heating

Olive leaves (Kronakii cultivar) were obtained from the annual pruning of olive trees and pressed to obtain a crude juice. Aliquots from the concentrated crude olive leaf juice, representing 400, 800, 1600 and 2400 ppm as polyphenols, were added to sunflower oil. Samples of sunflower oil mixed with olive leaf juice were heated intermittently at 180 ± 5 °C for 5 h day^?1 and the heating process was repeated for five consecutive days. A control experiment was performed where butylated hydroxyl toluene (BHT) at 200 ppm was added to sunflower oil prior to intermittent heating in order to compare the antioxidant efficiency between the natural polyphenolics of olive leaf juice and synthetic antioxidant BHT. Some physical and chemical constants for the unheated and heated sunflower oil were determined. The data indicate that the addition of olive leaf juice to sunflower oil heated at 180 °C induced remarkable antioxidant activity and at 800 ppm level was superior to that of BHT in increasing sunflower oil stability.     

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。     

Vegetable Oils Replace Pork Backfat for Low-Fat Frankfurters

Low-fat frankfurters (10% fat, 12.5% protein) with olive, corn, sunflower or soybean oils, compared to control (29.1% animal fat, 10.4% protein) had 67% lower total fat, 40–45% lower saturated fatty acids, 50–53% lower calories, reduced cholesterol and 20% higher meat protein. Although they had darker red color they were 6–7.2% lower in processing yield and had higher purge accumulation, were firmer and less juicy. The type oil had no effect (P>0.05) on these characteristics but affected fatty acid composition. Frankfurters with olive oil had 41.8% higher monounsaturated fatty acids and those with seed oils 5–7 times higher polyunsaturated fatty acids. Soybean oil increased lin-olenic acid content and negatively affected overall acceptability and shelf-life.     

橄榄油与橄榄油基二酯油煎炸薯条 品质差异分析

甘油二酯(DAG)作为一种低热值的功能性脂质,因其特殊的理化性质和生理功能被广泛应用于食品体系中。为了考察DAG油作为煎炸油的可行性,以橄榄油基二酯油(ODO,82.3%)和橄榄油(OO,92.43%)煎炸薯条,对比研究两种油煎炸后的薯条在水分含量、质构、油含量、色泽、淀粉糊化度以及体外模拟消化淀粉水解率等方面的差异,并用扫描电子显微镜观察消化过程中薯条表面的微观形态变化,最后对两种油煎炸的薯条进行感官评价。结果表明：ODO煎炸薯条的水分含量(57.07%)、油含量(28.15%)、淀粉糊化度(90.7%)、体外模拟消化淀粉水解率(63.02%)分别高于OO煎炸薯条的水分含量(49.93%)、油含量(25.74%)、淀粉糊化度(88.3%)和体外模拟消化淀粉水解率(53.47%);在质构和色泽上,与OO煎炸薯条相比,ODO煎炸薯条具有更高的脆度、更低的硬度及更好的色泽;从微观形态看,ODO煎炸薯条外表面淀粉颗粒的收缩、分散和变形更明显,经体外模拟消化后,OO和ODO煎炸薯条均发生了较大的细胞破裂,其中ODO煎炸薯条显微结构破坏更严重;OO和ODO煎炸薯条在口感、外观、风味、油腻性、脆度...     

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。     

Effect of an Ethanol Extract from Summer Savory (Saturejae hortensisL) on the Stability of Sunflower Oil at Frying Temperature

The effect of the ethanol extract from Saturejae hortensis L on the oxidative and thermal processes occurring in sunflower oil during its high-temperature treatment (180°C) was investigated. The changes during simulated deep fat frying were monitored by determination of the oxidation stability at 100°C, as well as by determination of unchanged triacylglycerols. It was established that the addition of 1 and 5 g kg^-1 ethanol extract from S hortensis L leads to a decrease in the oxidative and thermal changes in the oil. The ethanol extract from S hortensis L improved the oxidative stability of sunflower oil even after 50 h at 180°C and it inhibited the oxidative processes more than the thermal processes under these conditions. © 1997 SCI.     

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...     

葵花籽流化床干燥的研究

通过三因素二次组合设计以及SPSS13.0等方法,对鲜葵花籽流化床干燥进行研究,获得回归方程,并利用其求得葵花籽流化床干燥最佳条件为空床气速1.4235m/s,热空气温度65.0693℃,流化床层高度(静止床)93.4934mm。     

Effect of potato presence on the degradation of extra virgin olive oil during frying

This work investigates the effect of potato presence on the degradation of extra virgin olive oil (EVOO) during repeated frying. For this reason the performance of EVOO during frying was compared with its performance during heating at frying temperatures. In order to make meaningful comparisons the temperature profiles obtained during the frying experiments were replicated during the heating experiments by means of a high energy exchange rate cooling/heating system. The effects of potato‐to‐oil ratio (1/7 and 1/35 kg_potatoes/L_oil) and number (N) of batches (N = 0, 1, 0, 20, 30, 40) were examined. EVOO was analysed using high performance size exclusion chromatography (HPSEC). It was found that polymerisation products increased linearly during frying and heating and that they were not affected by potatoes presence at low ratio. The effect of potato presence became statistically significant (yet not remarkable) at the high ratio. Decomposition products increased during frying whereas they decreased during heating.