油茶籽油热稳定性研究

发布时间：2018-06-10 12:46

  本文选题：油茶籽油 + 热氧化稳定性　； 参考：《中南林业科技大学》2017年博士论文

【摘要】：油茶籽油是纯天然木本食用植物油,富含油酸和抗氧化活性微量组分,是可以和橄榄油相媲美的高级食用油。然而,消费者对油茶籽油总体认知程度较低,因此需大力开展油茶籽油基础特性研究,为提高油茶籽油的市场影响力提供基础理论和科学依据。目前有关油茶籽油品质研究主要集中在加工和贮藏过程中的氧化稳定性研究,而高温处理过程中热氧化稳定性研究相对较少。本课题采用两种高温处理方式,从初始底物损失和初级/次级氧化产物生成两方面研究油茶籽油的热氧化稳定性。为改进油茶籽油加工工艺,监控油茶籽油高温品质,扩大油茶籽油应用范围和提高油茶籽油认知度等提供科学理论依据。(1)ELSD-HPLC分析油茶籽油甘三酯最终优化色谱条件为:流动相组成为乙腈(A)和异丙醇(B),流速1.2mL/min,柱温25℃;梯度洗脱条件:0-1min,60%A,40%B;1-15 min,60-70%A,40-30%B;15-60 min,70%A,30%B;60-75 min,70-60%A,30-40%B;75-88 min,60%A,40%B。ELSD 检测器参数:漂移管温度80℃、空气流速2.8 L/min、增益为1。在此优化条件下测得油茶籽油由12种甘三酯组成。Rancimat操作参数中温度对油茶籽油OSI影响显著(P0.01),与样品量相比,空气流速对油茶籽油OSI影响较显著(P0.05)。油茶籽油温度系数和Q10分别为-3.02×10-2和2.02。推算油茶籽油货架期(20℃下的OSI)存在显著差异,表明用加速氧化方法评价油脂货架期可能存在误差。(2)感官评价表明:温度越高油茶籽油感官品质劣变越快,且与菜籽油相比,油茶籽油在高温处理过程中可保持良好感官品质。加速氧化试验中理化指标分析表明:120℃下油茶籽油总体氧化水平高于180℃,而180℃下油茶籽油中非挥发性羰基化合物和含有共轭二烯和三烯次级氧化产物生成速率和累积量均高于120℃。深度煎炸试验结果表明:油茶籽油初级、次级和总体氧化程度及非挥发性羰基化合物等次级氧化物的累积量均低于菜籽油,说明油茶籽油具有良好的热氧化稳定性,可作为优良煎炸油。此外,煎炸材料对煎炸油氧化程度具有一定影响,但对煎炸油水解程度影响显著。高温处理过程中油茶籽油极性组分含量增加与时间显著相关(R20.98),且温度越高油茶籽油中极性组分含量越高,与菜籽油相比在深度煎炸试验油茶籽油中极性组分含量水平较低。(3)加速氧化试验结果表明:温度对油茶籽油不饱和脂肪酸影响显著,温度越高不饱和脂肪酸降解越迅速,且随不饱和程度增加损失率逐步增加。此外,180℃高温处理会导致油茶籽油中微量反式油酸生成。深度煎炸试验表明:油茶籽油和菜籽油脂肪酸组成差异性导致两个油样脂肪酸降解模式明显不同,说明脂肪酸组成是影响油脂热稳定的关键因素;与多不饱和脂肪酸含量较高的菜籽油相比,高油酸的油茶籽油热稳定性更好。在深度煎炸和对照加热油茶籽油和菜籽油中均检测到反式油酸,但含量低于我国食用油中反式脂肪酸推荐限量(2 g/100 g)。值得注意的是,菜籽油在此过程中还可能会生成反式亚油酸和亚麻酸。因此,从煎炸油安全性和营养特性考虑,油茶籽油表现出良好的热稳定性。C18:2/C16:0,SFA/UFA,MUFA/PUFA 和 Cox value等脂肪酸综合指标与极性组分含量和加热时间显著相关(R20.97),可用于评价油脂在高温处理过程中的降解程度。(4)不同产地油茶籽油TAG分布存在差异。加速氧化试验结果表明:温度越高油茶籽油TAG降解越迅速,且不同温度下降解模式明显不同。此外,TAG含量水平也会影响其降解速率。深度煎炸试验结果表明:油脂甘三酯组成显著影响其降解模式,富含不饱和程度较大甘三酯的菜籽油在高温处理过程中更易产生降低煎炸油品质的氧化初级和次级产物,油茶籽油则表现出良好的热氧化稳定性。PTAG分析表明:在加速氧化试验中,180℃下油茶籽油的聚合程度显著高于120℃;在深度煎炸试验中,与菜籽油相比油茶籽油聚合程度较低。此外,与对照加热油样相比,深度煎炸油样中TAG降解和PTAG生成水平均较高,说明煎炸材料对油脂甘三酯降解也有一定影响。(5)煎炸油茶籽油中的极性组分具有助氧化性。HPSEC分析表明:高温处理油茶籽油极性组分和脂肪酸甲酯组成分别为TGO、TGD、ox-TGM、DG、FFA和FAO、FAD、ox-FAM。加速氧化试验结果表明:在120℃和180℃下油茶籽油反应历程截然不同,主导反应分别为氧化反应和聚合反应,且在120℃下的水解反应程度高于180℃。深度煎炸试验结果表明:与菜籽油相比油茶籽油中极性甘三酯和脂肪酸含量较低,说明油茶籽油劣变程度低,可作为优良煎炸油。氧化聚合和水解产物在油样中的分布表明:煎炸材料对油脂氧化聚合程度影响低于对油样水解程度影响。相关性分析表明:与化学指标相比,极性组分和极性脂肪酸甲酯HPSEC分析更能准确反应油脂在高温处理过程中的劣变进程。此外,各项评价油脂煎炸寿命的推荐指标分析表明:中国现行有关判定植物油煎炸寿命标准(27%TPC)可能存在风险。(6)挥发性醛是油茶籽油在高温处理过程中产生的主体挥发性化合物,约占挥发性化合物总含量的80%。加速氧化试验结果表明:高温导致油茶籽油中挥发性醛大量生成,温度越高生成越快;且不同温度下变化反应历程明显不同。深度煎炸试验结果研究表明:除温度外,脂肪酸组成和煎炸材料对油茶籽油挥发性醛生成具有显著影响。油酸酰基衍生的挥发性醛在油茶籽油中总体生成量高于菜籽油,而亚油酸和亚麻酸衍生的挥发性醛在菜籽油中生成量高于油茶籽油。此外,深度煎炸和对照加热油样中挥发性醛分布也存在差异,说明煎炸材料对油茶籽油中挥发性醛的生成也有一定影响。值得注意的是,深度煎炸和对照加热菜籽油中二烯醛总体水平分别是油茶籽油的7.72和7.13倍,二烯醛具有高反应性和细胞毒性,从油脂安全性和营养特性考虑,油茶籽油可作为优良煎炸油。
[Abstract]:Oil tea seed oil is a pure natural edible vegetable oil, which is rich in oleic acid and antioxidant activity. It is a high level edible oil comparable to olive oil. However, the overall cognition of oil tea seed oil is low. Therefore, it is necessary to develop the basic characteristics of camellia seed oil and provide a basis for improving the market influence of oil tea seed oil. The research on oil quality of oil tea seed oil is mainly focused on the study of oxidation stability during processing and storage, while the study of thermal oxidation stability is relatively less in the process of high temperature treatment. Two kinds of high temperature treatment methods are used to study oil tea from two aspects of initial substrate loss and initial secondary / secondary oxidation products. The thermal oxidation stability of seed oil provides scientific theoretical basis for improving the processing technology of camellia seed oil, monitoring the high temperature quality of oil tea seed oil, expanding the application range of camellia seed oil and improving the recognition degree of oil tea seed oil. (1) ELSD-HPLC analysis of the optimum chromatographic conditions for the analysis of three ester of oil tea seed oil GGM is that the flow phase group becomes acetonitrile (A) and isopropanol (B), and the flow rate is 1. 2mL/min, column temperature 25 C, gradient elution conditions: 0-1min, 60%A, 40%B, 1-15 min, 60-70%A, 40-30%B, 15-60 min, 70%A, 30%B, 60-75 min, 70-60%A, 75-88, 80, 80, air velocity 2.8, and gain 1. in this optimized condition that the oil tea seed oil is composed of 12 kinds of three ester of three ester of Camellia oleifera The effect of temperature on OSI of oil tea seed oil was significant (P0.01). Compared with the sample, the effect of air velocity on the OSI of oil tea seed oil was significant (P0.05). The temperature coefficient of oil tea seed oil and Q10 were -3.02 x 10-2 and 2.02., respectively, to calculate the shelf life of Camellia oleifera seed oil (OSI under 20 degrees C), indicating that the shelf life of oil could be evaluated by accelerated oxidation method. (2) the sensory evaluation showed that the higher the temperature, the faster the sensory quality of the oil tea seed oil changed, and the oil tea seed oil could maintain good sensory quality in the process of high temperature treatment compared with the rapeseed oil. The analysis of physical and chemical indexes in the accelerated oxidation test showed that the overall oxidation level of Camellia oleifera seed oil at 120 C was higher than that of 180, and the oil tea seed oil was not in 180 C. The formation rate and accumulation of secondary oxidation products of volatile carbonyl compounds and conjugated dienes and three alkenes were higher than 120. The results of deep frying test showed that the accumulation of secondary and overall oxidation degree and non volatile carbonyl compounds were lower than that of rapeseed oil, indicating that the oil of Camellia oleifera was good. The thermal oxidation stability can be used as an excellent frying oil. In addition, the frying material has a certain effect on the degree of oxidation of frying oil, but it has a significant influence on the degree of hydrolysis of frying oil. The increase of polar component content of oil tea seed oil is significantly related to time during high temperature treatment (R20.98), and the higher the temperature is, the higher the content of polar components in the oil tea seed oil, and the higher the content of the polar components in the oil tea seed oil. The level of polar components in the seed oil compared to the deep fried Camellia oleifera seed oil was lower. (3) the accelerated oxidation test showed that the temperature had a significant effect on the unsaturated fatty acids of the oil tea seed oil, the higher the temperature was, the faster the unsaturated fatty acid degradation and the increase of the loss rate with the increase of the unsaturated degree. In addition, the high temperature treatment at 180 degrees centigrade would lead to oil. The deep frying test showed that the difference in fatty acid composition of camellia seed oil and rapeseed oil resulted in a distinct difference in the fatty acid degradation mode of two oil samples, indicating that fatty acid composition was the key factor affecting the thermal stability of oil, compared with rapeseed oil with high polyunsaturated fatty acid content, high oleic acid oil camellia seed Oil thermal stability is better. Trans oleic acid is detected in deep fried and controlled heated oil tea seed oil and rapeseed oil, but the content is lower than the recommended limit of trans fatty acid (2 g/100 g) in Chinese edible oil. It is worth noting that rapeseed oil may also produce trans linoleic acid and linolenic acid in this process. Therefore, the safety and camping of frying oil will be obtained. Considering the cultivation characteristics, the oil tea seed oil showed good thermal stability.C18:2/C16:0, SFA/UFA, MUFA/PUFA and Cox value and other fatty acid comprehensive indexes were significantly related to the content of polar components and heating time (R20.97), which could be used to evaluate the degree of degradation of oil in the process of high temperature treatment. (4) the distribution of TAG in oil tea seed oil from different habitats was different. The results of the oxidation test showed that the higher the temperature was, the faster the TAG degradation of oil tea seed oil, and the different degradation modes at different temperatures. In addition, the level of TAG content would also affect the degradation rate. The results of deep frying test showed that the composition of the fatty Gan three ester significantly affected the degradation mode, and the rapeseed oil rich in the high unsaturated degree of Gan three ester was at high temperature. In the process of treatment, the oxidation primary and secondary products to reduce the quality of the frying oil were more easily produced. The oil tea seed oil showed good thermal oxidation stability.PTAG analysis showed that in the accelerated oxidation test, the degree of polymerization of Camellia oleifera seed oil at 180 C was significantly higher than that of 120; in deep frying test, the degree of polymerization of oil tea seed oil compared with rapeseed oil was better than that of rapeseed oil. In addition, compared with the control heating oil samples, the TAG degradation and the PTAG production level in the deep fried oil samples were all higher, indicating that the frying material had a certain effect on the degradation of oil Gan three ester. (5) the polar components in the fried Camellia oleifera seed oil showed the oxidative.HPSEC analysis showed that the composition and composition of fatty acid methyl esters in the oil tea seed oil were treated with high temperature. TGO, TGD, ox-TGM, DG, FFA and FAO, FAD, ox-FAM. accelerated oxidation test results showed that the reaction course of oil tea seed oil at 120 and 180 was completely different, the dominant reaction was oxidation reaction and polymerization reaction respectively, and the degree of hydrolysis reaction at 120 C was higher than 180. Deep frying test showed that the oil tea seed oil was compared with rapeseed oil. The content of sexual Gan three ester and fatty acid is low, indicating that the oil tea seed oil has low deterioration degree and can be used as excellent frying oil. The distribution of oxidative polymerization and hydrolysates in oil samples shows that the influence of frying material on the degree of oxidative polymerization of oil is lower than that on the degree of oil hydrolysis. The HPSEC analysis of fatty acid methyl ester can more accurately reflect the deterioration process of oil in the process of high temperature treatment. In addition, the analysis of the recommended indexes for evaluating the life of oil frying shows that there may be risks in determining the life standard of frying life of plants (27%TPC) in China. (6) the volatile aldehyde is the main body of oil tea seed oil in the process of high temperature treatment. The 80%. accelerated oxidation test of volatile compounds, which accounts for approximately the total content of volatile compounds, shows that high temperature leads to the formation of volatile aldehydes in oil tea seed oil, the higher the temperature is, the faster the formation of the volatile aldehydes, and the change of the reaction process at different temperatures is distinct. The production of volatile aldehydes derived from oleic acid group was higher than that of rapeseed oil in oil tea seed oil, while the amount of volatile aldehydes derived from linoleic acid and linolenic acid in rapeseed oil was higher than that of Camellia oleifera seed oil. It is worth noting that the overall level of dienaldehyde in deep frying and controlled heated rapeseed oil is 7.72 and 7.13 times as high as that of Camellia oleifera seed oil, and dienaldehyde has high reactivity and cytotoxicity. Good fried oil.
【学位授予单位】：中南林业科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TS225.14
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本文编号：2003273