Lee Jookyeong, Boo Changguk, Hong Seong-Jun, Shin Eui-Cheol
CASS Food Research Centre, School of Exercise and Nutrition Sciences, Faculty of Health, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia.
Department of Food Science/Institute for Food Sensory & Cognitive Science, Gyeongsang National University, Jinju, Gyeongnam 52725, Korea.
Foods. 2021 Apr 29;10(5):972. doi: 10.3390/foods10050972.
This study investigated chemosensory degradations of soybean and canola oils with repeated frying in order to estimate the quality of the oils.
Chemical parameters including oxygen induction time, acid value, -anisidine value, malondialdehyde, and total polar compounds were measured. Electronic nose and electronic tongue analyses were performed to assess sensory properties. Multivariate analyses were employed to investigate relationships among tastes and volatile compounds using principal component analysis (PCA) and Pearson's correlation analysis.
All chemical parameters increased with repeated frying in both oils. Electronic nose analysis found ethyl butyrate, 2-heptenal, and 2,4-pentanedione as major volatiles for soybean oil and ethyl butyrate and linalool for canola oil. As the numbers of frying increased, all volatiles showed an increased concentration in various extents. In multivariate analyses, ethyl butyrate revealed strong positive correlations with sourness, umami, and sweetness, and umami showed strong positive correlations with sourness and saltiness ( < 0.05). PCA confirmed that in PC1 with 49% variance, sourness, saltiness, and umami were at similar rates while acetyl pyrazine, 2,4-pentadieone, and 1-octanol were found at similar rates. Canola oil was chemically more stable and less susceptible to deterioration in all chemical parameters compared to soybean oil, resulting in a relatively better quality oil when repeatedly fried.
The results suggested that minimum repeated frying (5 times) degrades chemosensory characteristics of both oils, thereby compromising their quality. The findings of this study will be utilized as a foundation for quality control of fried foods in food industry, fried food development, and fast-food industry.
本研究调查了大豆油和菜籽油在反复油炸过程中的化学感官降解情况，以评估油的质量。
测量了包括氧化诱导时间、酸值、对茴香胺值、丙二醛和总极性化合物在内的化学参数。进行了电子鼻和电子舌分析以评估感官特性。采用多变量分析，通过主成分分析（PCA）和皮尔逊相关分析研究味道与挥发性化合物之间的关系。
两种油在反复油炸过程中所有化学参数均增加。电子鼻分析发现，大豆油的主要挥发性成分是丁酸乙酯、2-庚烯醛和2,4-戊二酮，菜籽油的主要挥发性成分是丁酸乙酯和芳樟醇。随着油炸次数的增加，所有挥发性成分的浓度都有不同程度的增加。在多变量分析中，丁酸乙酯与酸味、鲜味和甜味呈强正相关，鲜味与酸味和咸味呈强正相关（<0.05）。PCA证实，在方差占49%的主成分1中，酸味、咸味和鲜味的含量相似，而乙酰吡嗪、2,4-戊二酮和1-辛醇的含量相似。与大豆油相比，菜籽油在所有化学参数上化学稳定性更高，更不易变质，因此反复油炸时质量相对更好。
结果表明，最少的反复油炸（5次）会降低两种油的化学感官特性，从而影响其质量。本研究结果将为食品工业、油炸食品开发和快餐行业中油炸食品的质量控制奠定基础。
