煎炸转基因大豆油动力学特性及品质的快速鉴别方法研究

发布时间：2018-05-13 20:57

本文选题：大豆油 + 间断煎炸　；参考：《河南农业大学》2012年硕士论文

【摘要】：食用油经高温煎炸会发生热分解、热聚合、热氧化聚合、水解、缩合、氧化等一系列化学反应，产生一些挥发性的醛、酮、酯等有害物质，并引起煎炸油色泽、风味、粘度、酸价、过氧化值、羰基价等特性发生变化，存在影响人体健康的隐患。因此，寻找快速鉴别煎炸油食用品质特性的新型表述参数同时进行现场快速分析，具有重要的现实意义。实验以国家颁布的羰基价指标为对照标准，用不同产地的市售食用转基因大豆油为样品，分别采用间断性反复煎炸油条和间断反复加热大豆油的方法，研究煎炸食品和非煎炸食品加热过程中，当羰基价的含量超出国家标准时，大豆油pH值、电导率、粘度、酸价和过氧化值的动力学特性及变化速率，同时记述煎炸过程中大豆油的感观现象。随煎炸时间的增加，大豆油由最初的柠檬色逐渐加深至棕黑色，透明度不断降低，最后严重浑浊；气味由最初的油香味变成刺鼻的哈喇味；发烟情况也越来越严重，最后甚至刺激眼睛发酸流泪；煎炸约5h后出现起泡现象，煎炸约9h后哈喇味极重，产生的泡沫充满整个油面，炸出的油条难以下咽。在煎炸食品和非煎炸食品加热过程中，随着时间的延长，大豆油的羰基价明显升高，呈极显著的直线上升趋势，且符合线性回归方程；pH值逐渐降低；在煎炸过程中，电导率整体呈现上升趋势，在非煎炸食品加热过程中，电导率变化不大，数值基本稳定；粘度呈现明显的直线上升趋势，有良好的线性关系；酸价整体呈现上升的趋势，但变化起伏不呈线性关系；过氧化值呈现出不规则的变化，无规律可循。累计煎炸和加热12h时，羰基价已超过国家标准，酸价和过氧化值均未超出国家标准，但酸价在煎炸8h后增幅较大，过氧化值在12h后超出国家标准，此时pH均值为4.16，H~+活度、电导率为新鲜豆油的100倍和5倍左右，粘度均值为85.39mpa·s，约为新鲜豆油的2倍，，大豆油不宜再食用。建议将pH值4.20作为快速鉴别煎炸大豆油食用品质特性的新型表述参数。大豆油的羰基价、H~+活度、粘度、酸价、过氧化值与煎炸时间之间都具有极显著的相关关系；电导率与煎炸时间的相关程度一般显著；H~+活度、粘度与羰基价之间均存在极显著的相关关系，相关程度非常密切；酸价、过氧化值与羰基价的关系较为密切；电导率与羰基价关系显著，相关程度一般密切；电导率与粘度、酸价、过氧化值之间不存在相关性。
[Abstract]:A series of chemical reactions, such as thermal decomposition, thermal polymerization, thermal oxidation polymerization, hydrolysis, condensation, oxidation and so on, will take place in the cooking oil after high temperature frying, resulting in some volatile harmful substances, such as aldehydes, ketones, esters, etc., and resulting in the frying oil color, flavor, viscosity, etc. Acid value, peroxide value, carbonyl value and other properties change, there are hidden dangers affecting human health. Therefore, it is of great practical significance to find a new description parameter for fast identification of edible quality characteristics of fried oil and to carry out field rapid analysis at the same time. In this experiment, the carbonyl price index issued by our country was taken as the control standard, and the commercial edible transgenic soybean oil from different producing areas was used as the sample. The method of intermittent repeated frying oil strips and intermittent and repeated heating of soybean oil was used, respectively. The kinetic characteristics and change rate of pH value, conductivity, viscosity, acid value and peroxide value of soybean oil during heating process of fried food and non-fried food were studied when the content of carbonyl value exceeded the national standard. At the same time, the sensory phenomenon of soybean oil during frying was described. With the increase of frying time, soybean oil gradually deepened from the original lemon color to the brown and black color, the transparency of soybean oil gradually decreased, and finally it became seriously cloudy; the smell changed from the original oil flavor to the pungent Hala flavor; and the smoking situation became more and more serious. Finally, the eyes were irritated with acid and tears. After frying for about 5 hours, bubbles appeared. After frying for about 9 hours, the Hala taste was very heavy, the foam produced was filled with the whole oil surface, and the fried oil strips were difficult to swallow. In the heating process of fried food and non-fried food, the carbonyl value of soybean oil increased obviously with the prolongation of time, and showed a very significant linear upward trend, and the pH value of soybean oil decreased gradually in accordance with the linear regression equation. The electrical conductivity showed an upward trend. In the heating process of non-fried food, the electrical conductivity changed little, the numerical value was basically stable, the viscosity showed an obvious linear upward trend, there was a good linear relationship, and the overall acid price showed an upward trend. However, there was no linear relationship between the fluctuation and fluctuation, and the peroxide value showed irregular change, and there was no rule to follow. After frying and heating for 12 h, the carbonyl value exceeded the national standard, the acid value and peroxide value did not exceed the national standard, but the acid value increased significantly after frying for 8 h, and the peroxide value exceeded the national standard after 12 hours. The mean pH value was 4.16 h ~. The conductivity of soybean oil is about 100 times and 5 times of that of fresh soybean oil. The average viscosity of soybean oil is about 2 times that of fresh soybean oil, and the average viscosity of soybean oil is about 2 times that of fresh soybean oil. It was suggested that pH 4.20 should be used as a new expression parameter for quick identification of edible quality characteristics of fried soybean oil. The correlation between the activity, viscosity, acid value, peroxide value and frying time of soybean oil was significant, and the correlation between electrical conductivity and frying time was significant. There is a very significant correlation between viscosity and carbonyl valence, the correlation degree is very close; acid value, peroxide value and carbonyl value are more closely related; conductivity and carbonyl value have a significant relationship, correlation degree is generally close; conductivity and viscosity, There is no correlation between acid value and peroxide value.
【学位授予单位】：河南农业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R155.5

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