Effect of cooking method on the formation of 7-ketocholesterol in Atlantic hake (Merluccius hubbsi) and smooth weakfish (Cynoscion leiarchus) fillets

Abstract

The levels of cholesterol and 7-ketocholesterol were measured in raw Atlantic hake (Merluccius hubbsi) and smooth weakfish (Cynoscion leiarchus) fillets and in fillets subjected to the following cooking methods: baking in an electric or microwave oven; baking, grilling or stewing in a steam-convection oven; simmering on a stove; electric grilling; and deep frying. The raw samples from both fishes exhibited significantly (p < 0.05) higher cholesterol levels (62.71 ± 6.06 mg/100 ge74.16 ± 3.96 mg/ 100 g) than the processed fillets. In all of the samples, 7-ketocholesterol was detected at significantly (p < 0.05) different levels depending on the cooking method and the type of fish. Steam cooking keeping the surface of the product moist produced small decrease in the cholesterol content (26.65%e29.96%) and a low level of 7-ketocholesterol in the samples (6.90 ± 0.21 mg/ge6.47 ± 0.28 mg/g). Baking in electric or steam-convection ovens at high temperatures and long times greatly reduced the cholesterol content (52.77%e65.08%), which was associated with a large increase in 7-ketocholesterol levels (11.54 ± 0.45 mg/ge13.94 ± 1.17 mg/g). These results indicate the necessity of revising the baking procedures for fish to increase the healthiness of food.

Physicochemical and fatty acid characteristics of stewed pork as affected by cooking method and time

“…This result is in agreement with the findings of Freitas et al . () who observed a decrease in cholesterol content after pan‐frying or deep‐frying white sucker and bluegill lake trout fillets. In addition, as a consequence of longer cooking times, an increased amount of subcutaneous fat would be melted, leading to further reduction in cholesterol content.…”

Formation of oxysterols during thermal processing and frozen storage of cooked minced meat

“…Animal fat such as pork lard and beef tallow (present in the meatloaf) contains predominantly saturated and monounsaturated fatty acids with high oxidation stability . These fatty acids probably do not contribute to cholesterol oxidation in contrast to polyunsaturated fatty acids …”

Use of Natural Antioxidants in the Inhibition of Cholesterol Oxidation: A Review

“…During thermal processing, changes such as a loss of antioxidant enzyme activity, disruption of cell membranes, which bring polyunsaturated fatty acids into contact with pro-oxidants, and thermal decomposition of hydroperoxides to pro-oxidant species are responsible for the increase in cholesterol oxidation rate (Hur et al, 2007). Many authors have investigated the instability of the cholesterol molecule during thermal processing (Ansorena et al, 2013;Barriuso et al, 2016;Derewiaka, & Molińska, 2015;Ferreira et al, 2017;Freitas, Amaral, Coutrim, Afonso, & Junqueira, 2015;Leal-Castañeda, Hernández-Becerra, Rodríguez-Estrada, & García, 2017;Saldanha, Benassi, & Bragagnolo, 2008;Tarvainen, Quirin, Kallio, & Yang, 2016;Xu et al, 2016).…”

“…Fish and fish products Fish are noted for their high levels of polyunsaturated fatty acids of the omega-3 series, such as eicosapentaenoic acids (EPA, C20: 5) and docosahexaenoic acids (DHA, C22: 6), which are compounds directly related to health benefits (Calder, 2015;Haimeur Raatz, Silverstein, Jahns, & Picklo, 2013;Zheng, Hu, Zhao, Yang, & Li, 2013). However, the lipid fraction of fish, which is composed mainly of PUFAs and with high levels of cholesterol, is particularly susceptible to oxidation processes when exposed to favorable factors during processing and storage (Dantas et al, 2015;Freitas et al, 2015;Márquez-Ruiz & Morales, 2015;Saldanha et al, 2008). In addition, the presence of pigments, such as myoglobin and hemoglobin, and traces of metal ions in fish makes this food matrix more susceptible to oxidation.…”