Inhibitory effect of antioxidants on key off-odors in French fries and oils and prolong the optimum frying stage

The flavor formation of fried food experienced an optimum stage, fried food obtained more desirable flavor during this stage. In order to improve the flavor of French Fries (FFs), the optimum stage was prolonged by adding several antioxidants (tert-butyl hydroquinone (TBHQ), L-ascorbyl palmitat (L-ap), and rosemary) to the frying soybean oil (SO). The results of sensory evaluation showed that antioxidants had an effect on prolonging the optimum stage. Compared with the control group, the optimum stage of SO added with TBHQ, L-ap and rosemary was prolonged by 25%, 50% and 25%, respectively. Furthermore, antioxidants can effectively inhibit the degradation of some desirable compounds (e. g. (E, E)-2,4-decadienal) and reduce the generation of off-flavor (hexanal, hexanoic acid, heptanoic acid, octanoic acid, and nonanoic acid) during frying. Among them, the TBHQ performed best on inhibiting the increase of total polar compounds, acid value and p-Anisidine value, besides, it had the best effect on reducing the degradation of (E, E)-2,4-decadienal and inhibiting the generation of saturated aldehydes, especially the hexanal. The L-ap showed better abilities to inhibit the generation of off-flavor acids. This study can provide a basis for the effects of different antioxidants in prolonging the optimum stage and inhibiting the off-flavor.