Effects of Combining Antioxidants on the Oxidative Stability of Refined, Bleached and Deodorized Palm Olein during Continuous Deep Frying of Potato Chips

In this study, the effect of a novel antioxidants composite system based on a synergetic composite between Tertiary butyl hydroquinone (TBHQ), Ascorbyl palmitate, citric acid, and Dimethicone have been evaluated against the classical common antioxidant system based on TBHQ at the highest permitted dose of 200 ppm during successive deep-frying cycles. Also, the shelf life of fried food and its sensory performance and oil absorption content o fried food were comparatively studied. The Novel antioxidant composite system is a synergetic blend of an artificial antioxidant, TBHQ and vitamin C palmitate( Ascorbyl palmitate) as natural identical antioxidants, an effective sequestrant which is Citric acid and poly dimethyl siloxane as an anti-foaming system to obtain the highest oxidative stability impact during deep frying. The frying processes were carried at 180 ᴼC for sliced potato chips for 8 successive frying cycles.Sensory evaluation of the fried potato has been conducted under accelerated storage conditions to determine the effect of the oil oxidative stability on the shelf life of fried food. The oxidative degradation of the oil was evaluated by measuring different oxidation and degradation parameters for their respective peroxide value ( PV), free fatty acid( FFA %), the content of conjugated dienes, P-anisidine value,( p-A.V), induction period (IP), and Lovibond color. The (%) of oil absorption in the potato chips was also measured. The sensory evaluation has been done for fried foods to evaluate the crunchiness and likability of obtained french fries. Results revealed that the jump in primary & secondary oxidation parameters as PV and p- A.V.of palm olein after 8 successive frying cycles was very limited for the antioxidant composite system I by only 1.842± 0.1 meq O2/ kg in PV and by 6.2315±0.45 for p-A.V. Same for FFA, the jump was limited for the antioxidant composite system I for only 0.084+/-0.005 as well. However, the final PV, FFA after the 8 frying cycles are still within the Codex and local Egyptian regulation limits the edible oil human usage. Same for other quality parameters like color jump was limited to 3.4 Red jumps on Lovi bond scale for composite I. Study proofed that palm olein fortified with 650 ppm of the antioxidant composite (I) consists of TBHQ, Ascorbyl palmitate, citric acid, and polydimethylsiloxane at the specified synergistic ratios gives outstanding stability to refined Palm olein during the successive deep frying up to 8 successive frying cycles. It also achieved less oil absorption for french fries by about 3.5% less than the same oil fortified with 200 ppm TBHQ, which is the highest permitted dose of this strong antioxidant. (P≤0.05). Furthermore, sensory evaluation of the fried potatoes has been improved with the novel antioxidant system compared to theclassical TBHQ system.