Zhongguo youzhi (Mar 2023)
大豆油和棕榈油煎炸薯条过程品质评价Quality evaluation of soybean oil and palm oil during frying French fries
Abstract
为了对中包装的大豆油棕榈油煎炸专用调和油配方的开发和煎炸稳定性相关理化指标的选择提供参考，分别以一级大豆油、分提18 ℃棕榈油（一次精炼）及同批次的二次精炼18 ℃棕榈油为煎炸油，模拟薯条在180 ℃下高温煎炸32 h，对3种油品在煎炸过程中的酸值、过氧化值、p-茴香胺值、脂肪酸组成、极性组分含量、生育酚含量等理化指标进行了检测，并对18 ℃棕榈油中的风险因子，如PAH4、苯并（a）芘、3-氯丙醇酯（3-MCPDE）、反式脂肪酸含量进行了分析。结果表明：3种油品的酸值、过氧化值在煎炸过程中变化不明显，而p-茴香胺值、脂肪酸组成、极性组分含量在煎炸过程中变化比较明显；3种油品的生育酚氧化速度总体偏差不大；分提18 ℃棕榈油、二次精炼18 ℃棕榈油中的苯并（a）芘、反式脂肪酸含量均随煎炸时间延长呈缓慢升高的趋势；二次精炼18 ℃棕榈油的3-MCPDE在未煎炸时远高于分提18 ℃棕榈油的，3-MCPDE在煎炸初期降解剧烈，最终达到平衡；分提18 ℃棕榈油与二次精炼18 ℃棕榈油在煎炸稳定性方面没有明显区别，二次精炼不仅损失了部分有益的微量营养成分（如生育酚），还伴生出新的风险因子，如增加了3-MCPDE、反式脂肪酸。综上，酸值、过氧化值不能作为评价煎炸稳定性的敏感指标，而p-茴香胺值、脂肪酸组成、极性组分含量可作为敏感指标联合应用于评价煎炸油煎炸稳定性，另外，应倡导适度加工，以降低精炼过程营养成分的损失，同时避免风险因子的生成。 In order to provide a reference for the development of the formulation of a medium-packed special blend oil soybean oil and palm oil for frying and the selection of physicochemical indexes related to the stability of frying, soybean oil, fractionated 18 ℃ palm oil (primary refining) and secondary refined 18 ℃ palm oil from the same batch were used as frying oils to simulate the frying conditions of French fries at a high temperature of 180 ℃ for 32 h, and the physicochemical indexes of the three oils during frying such as acid value, peroxide value, p-anisidine value, fatty acid composition, polar fraction content and tocopherol content were investigated. In addition, risk factors such as PAH4, benzo(a)pyrene, 3-chloropropanol ester (3-MCPDE) and trans fatty acids in the 18 ℃ palm oil were also analyzed. The results showed that the acid value and peroxide value of the three oils did not change significantly during frying, while p-anisidine value, fatty acid composition and polar fraction content changed significantly, and the oxidation rate of tocopherols did not deviate significantly overall. The benzo(a)pyrene and trans fatty acids contents in the fractionated 18 ℃ palm oil and the secondary refined 18 ℃ palm oil showed a slow increase trend. The 3-MCPDE content of the secondary refined 18 ℃ palm oil was much higher than that of the fractionated 18 ℃ palm oil at the time of unfrying, and the 3-MCPDE degraded dramatically at the beginning of frying and eventually reached equilibrium. There was no significant difference in frying stability between fractionated 18 ℃ palm oil and secondary refined 18 ℃ palm oil, and secondary refining not only could lose some beneficial micronutrients (e.g. tocopherols), but also could generate new risk factors, such as an increase in 3-MCPDE and trans fatty acids. In conclusion, the acid value and peroxide value can not be used as sensitive indicators for frying stability of frying oils, while p-anisidine value, fatty acid composition and polar fraction content can be used as sensitive indicators for frying stability of frying oils. In addition, moderate processing should be advocated to reduce the loss of nutrients during refining and to avoid the generation of risk factors.
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