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The extractability of the main oak ellagitannins has been studied in five model solutions containing different types of oak chips (two sizes and different toasting degrees for each size). A new extraction kinetic model has been proposed from the quantitative experimental results obtained by means of HPLCeESI-MS/MS-multiple reaction monitoring method. The model considers an initial extraction (i.e., washing step) followed by a diffusion step, which involves two different processes that follow first-order kinetics at different rates. Differences in the extractability of the ellagitannins in the different model solutions have been observed and explained on the basis of the kinetic model here proposed.

Deep-fat frying is an important method of food preparation in which foods are immersed in hot oil. Repeated use of frying oils is a common practice, and in the presence of atmospheric oxygen it produces various undesirable reactions in used oils. Stable frying oils usually require low linolenic acid (LnA < 3%), increased oleic acid (OA > 40%), and decreased linoleic acid (LA < 50%). The aim of this study was to establish the behavior of palm superolein (PSO) (OA 45%; LA 12.5%; LnA 0.2%) and olive oil (OO) during repeated, discontinuous deep frying of French fries. The behavior of the oils under controlled heating conditions was also studied by maintaining all of the process variables the same as those in deep frying, except that there was no food in the oil. The PSO selected to be tested in this study may represent an alternative to OO as a frying medium. Although PSO presented a faster increase in some oxidation indices, such as free fatty acid and total polar compounds, for other indicators, PSO showed better behavior than OO (less formation of C8:0 and lower peroxide value).

Identification of volatile compounds formed when frying food represents an important tool to identify markers of oil thermal degradation, and can help to elucidate the chemical reactions occurring during deep frying. In particular, in this study the heat-induced degradation of edible oil has been evaluated by analyzing the composition of volatile organic compounds (VOCs) and fatty acids formed during intermittent frying with the aim of finding new possible markers to correlate with the total polar compounds (TPC) fraction. The frying was realized using a thermostatically temperature-controlled fryer at a temperature of 180 58C. A mixed oil constituted by palm, sunflower, and soybean frying oil and commercially available frozen potatoes have been used. The intermittent frying (4 h per day) with the same oil was repeated at 24 h intervals for a total of 40 h. VOCs were identification has been obtained by dynamic head space analysis combined with high resolution GC???MS. Among the VOCs, two compounds, namely (E,E)-2,4-decadienal, and (E)-2-undecenal, showed good correlations with the TPC values. NMR spectra (1H NMR) confirmed that 2-alkenals and alka-2,4-dienals are the major compounds formed during the deep frying