Impact of Deep‐Frying With Different Vegetable Oils on the Nutritional Quality of Grass Carp ( <scp> <i>Ctenopharyngodon idella</i> </scp> ) Fillets

The aim of this study was to determine the nutritional value (proximate composition, fatty acid profiles, nutritional quality indices (NQI), vitamins, and mineral contents) of deep-fried grass carp fillets with different vegetable oils (including olive oil, grape seed oil, and corn oil). The saturated fatty acids (SFAs) of deep-fried samples with corn oil were significantly decreased, while no significant differences were observed (<i>p</i> > 0.05) in the monounsaturated fatty acids (MUFAs) among various vegetable oils. The polyunsaturated fatty acids (PUFAs) content of fillets fried in grape seed oil and corn oil was almost three times that of the raw fillet. The highest and lowest fatty acid contents of the samples were MUFAs and SFAs, respectively. Fillets fried in grape seed oil and corn oil led to a significant reduction in the n-3/n-6 ratio. The samples fried with grape seed oil and corn oil exhibited increased PUFA/SFA, UFA/SFA ratios, and hypocholesterolemic/hypercholesterolemic (HH) index. Na content in fillets fried with olive oil was higher than in other treatments. P, Zn, Mg, and K contents have significantly decreased in the fried grass carp fillet. Frying the fillet with different vegetable oils did not significantly alter the Fe content compared to the raw fillet. Ca, Mn, and Cu contents of the grass carp fillet fried with olive oil significantly decreased, while other oils had no significant effect on Ca, Mn, and Cu contents. Vitamin D content in fillets fried in different oils did not differ significantly (<i>p</i> > 0/05). Vitamin A content in the raw fillet significantly increased after deep-frying with different vegetable oils. Deep-frying significantly reduced vitamins B₁ and B₃ content in grass carp fillets (<i>p</i> < 0/05). Generally, among all nutritional quality indices (NQI) except the n-3/n-6 ratio, fillets fried in grape seed oil and corn oil exhibited optimal lipid quality for human nutrition. In terms of nutrient retention, the data demonstrated that vitamins were best preserved with olive oil, and minerals were best preserved with corn oil.