Comparision of the frying performance of olive oil and palm superolein

Deep-fat frying is an important method of food preparation in wich 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 undesiderable reactions in used oils. Stable frying oils usually required low linolenic acid (LnA < 3%). The aim of this study was to establish the behaviour of palm superolein (PSO) (OA 45%, LA 12.5%, LnA 0.2%) and olive oil (OO) during repeated, discontinous deep frying of French fries. The behaviour 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 acid and total polar compounds, for other indicators, PSO showed better behaviour than OO (less formation of C8:0 and lower peroxide value)

Effect of size and toasting degree of oak chips used for winemaking on the ellagitannin content and on the acutissimin formation

[EN] The effect of size (2 and 8 mm) and toasting degree (light, medium and high) of oak chips on the C-glycosidic ellagitannins composition of model wine solutions has been studied by HPLC-ESI-MS-MS. Furthermore, the effect of the presence of (+)-catechin (50 mg/L and 200 mg/L) in the solution was assessed. Respecting toasting, the levels of ellagitannins were higher and reached earlier when light-toasted chips were used. Regarding chip size, the highest ellagitannin contents were found in the solutions in contact with the smallest oak chips. Nevertheless, the size of oak chips can be crucial depending on the toasting degree: high temperatures or long times of toasting can provoke the ellagitannin degradation from the whole chip if its size is too small. Acutissimins A and B were detected in the solutions containing (+)-catechin. Unlike the levels of acutissimins, the ellagitannin composition was not affected by the concentration of (+)-catechin in the solutions

Understanding the ellagitannin extraction process from oak wood

[EN] 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

Indicatori di trattamento termico nella frittura di patate surgelate

L’innalzamento termico (160-180°C) al quale viene sottoposto l’olio ri-utilizzato per la frittura determina la degradazione dell’olio stesso e lo sviluppo della componente organica volatile. Allo scopo di individuare possibili indicatori da affiancare e/o sostituire i composti polari totali (CPT max 25%), una miscela di oli è stata usata per friggere patate surgelate. Il trattamento termico discontinuo è stata condotto per 4 ore al giorno per 10 giorni. I campioni di olio sono stati sottoposti alla determinazione dei CPT, degli acidi grassi e dei composti organici volatili (COV) mediante purge and trap-GC/MS. La 2E, 4E-decadienale e la (E)-2-undecenal hanno evidenziato una buona correlazione con i CPT. L’acido ottanoico (C8:0) è stato evidenziato dalla 16a ora di trattamento nell’olio di frittura e delle patate

Indicatori di trattamento termico nella frittura intermittente

Scopo della ricerca è stato quello di individuare dei marcatori per lo stress termico dovuto alla frittura intermittente: i risultati hanno evidenziato cuna buona correlazione tra la (E,E9-2-4-decadienale e la (E)-2-undecanale ed i composti polari indicatori ufficiali di trattamento termic