A new analytical and statistical approach to predict the sensory properties of deep frying fats and oils to determine the point of discard during processing

摘要

The aim of this work was to explore the feasibility and limits of analytical criteria to assess the sensory properties of used frying oils and different fried food. Over a period of 2 years, 148 used frying oils collected in restaurants bakeries, fish caterers, and industrial plants were analyzed for a wide range of parameters, including sensory tests, total polar compounds (TPC), dimerized and polymerized triacyl-glycerols (DPTG), monomeric oxidized triacyl-glycerols (MONOX), acid value (AV), para-anisidine-value (AnV), and iodine value (IV). All methods were judged for their relevance, concerning the sensory quality of used frying oils categorizing the qualities as good or bad. The binary results were statistically evaluated using logit regression. The statistical evaluation of the tests was used to calculate the probability of occurrence of off-flavors which allows determining the point of discard and finally the point where the oil is certainly totally abused. All levels of degradation for used frying oils regardless of oil type and kind of food being fried can be statistically described and used to develop a simple equation using the TPC and AV value as variables (y = 117-8 x AV-3 x TPC) to find the point of disposal and to monitor the degradation process. The new criterion has been proven in the controlling of various industrial frying processes, restaurants and bakeries and kitchen frying.