Effects of adulterated palm cooking oil on the quality of fried chicken nuggets

Introduction. There is a rising concern over food safety caused by an increasing trend towards adulterating fresh cooking oil with used cooking oil in Malaysia. Recent decades have seen more cases of high-quality edible cooking oil adulteration with reused oil, driven by high market demand and profit margins. In this study, we aimed to analyze the properties of vegetable oils and their effect on the quality of fried chicken nuggets. Study objects and methods. We determined free fatty acid contents and characterized the properties of fresh palm olein, used cooking oil, and adulterated oil. We also compared the sensory quality attributes of chicken nuggets fried in fresh and adulterated oils. Results and discussion. The content of free fatty acids consistently increased with rising adulteration levels. The FTIR spectral analyses revealed significant differences between fresh, used, and adulterated oils at 3006, 2922, 2853, 2680, 1744, 1654, 987, 968, and 722 cm–1. The oil samples with high adulterant concentrations demonstrated a linear increasing trend in K232 and K 270 values, where higher absorbance values indicated severe deterioration in the oil quality. The sensory evaluation showed no significant effect (P > 0.05) of adulteration with used cooking oil on the quality of fried chicken nuggets. Conclusion. Our findings filled in a gap in the previous studies which only focused on the effects of adulteration on the oil properties. The study also provides valuable information to regulatory authorities on the reliability of quality parameters and modern instruments in edible oil adulteration detection.