Abstract
Frying oils with different alteration degrees were collected from continuous frying systems at various Spanish companies. These samples were used to evaluate the applicability, repeatability and capability of a number of methods to discriminate between samples of different degrees of oxidation. The objective of this work was to find complementary methods to the acid value determination for the routine quality control of the frying oils used in these companies. The optimization of the dielectric constant determination was accompanied by a clear variability improvement. However, except for the TBA value, the methods assayed showed lower variability. In addition, TBA value determination was discarded because this parameter showed insufficient sensitivity to discriminate between oil samples with different degrees of oxidation. Relationships between the alteration parameters determined in the frying media showed significant correlations between the acid value and several different oxidation parameters, such as the p-anisidine value, dielectric constant, lipid UV absorption and polymerized triacylglycerol content. Thus, since the acid value exclusively evaluates the hydrolytic alteration, these parameters give complementary information because they evaluate the thermoxidative alteration.
Highlights
Deep-fat frying is a process of cooking in which food is immersed into an edible oil or fat that serves as a heat-transfer medium and, in addition, such frying oil is an important ingredient of the fried food
Twelve oil samples representing both fresh oils and oils from normal and extreme continuous frying conditions were taken. These samples were collected from three Spanish snack food factories which fried with various types of oils with different degrees of unsaturation: sunflower oil (SO), palm olein (PO) and a palm olein/sunflower oil blend (30:70, v/v)
The precisions of these methods (RSD %) ranged from 0.9 to 4.1%, except for the determination of the thiobarbituric acid value (TBA) value (7.7%), which was discarded for this kind of samples, and for the determination of the dielectric constant
Summary
Deep-fat frying is a process of cooking in which food is immersed into an edible oil or fat that serves as a heat-transfer medium and, in addition, such frying oil is an important ingredient of the fried food. Oil is exposed to high temperature in the presence of air and moisture. Under these conditions, various chemical processes such as oxidation, hydrolysis and polymerization take place. Various chemical processes such as oxidation, hydrolysis and polymerization take place These thermoxidative processes induce changes in the quality of the frying oils and, the follow up of the oils’ deterioration is important for the production of high quality fried foods (Stevenson et al, 1984; Pokorny, 1999). If one begins with the premise that the ultimate achievable shelf life of the fried product depends on the quality of the frying oil throughout the process, frying oil would rarely need to be downgraded or discarded. The continuous production of high quality products with a crispy texture and appropriate flavor and shelf life is complex (Hammond, 2002)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
