Effect of different types of heat processing on chemical changes in tuna

Abstract

The chemical changes in skipjack tuna (Katsuwonus pelamis) subjected to cooking, frying, canning and microwave heating were studied. Raw tuna contained an unusual fatty acid C16:3 in high proportion (29.3%) followed by C18:2, C24:1, C16:0 and C18:3. Health beneficial fatty acids, eicosapentaenoic acid (EPA) (1.67%) and docosahexaenoic acid (DHA) (2.50%), were quite low with ω-3/ω-6 ratio 0.28. The total saturated fatty acids suffered major loss in fried (70%) and canned tuna (40%) due to loss of C16:0, C14:0 and C22:0. The monounsaturated fatty acids content increased (38%) in cooked and microwave heated tuna due to C24:1. The polyunsaturated fatty acids content increased in fried (50%) and canned (25%) tuna due to the uptake of frying and filling oil, respectively during processing. The loss of health beneficial ω-3 fatty acids, EPA and DHA were minimum in cooked tuna followed by microwave heated tuna. Canning totally destroyed these fatty acids. In fried tuna, the losses of EPA and DHA were 70 and 85%, respectively. Thiobarbituric acid - reactive substances values increased in heat processed tuna. Cholesterol increased in canned and microwave heated tuna but not in cooked tuna. Reduction of cholesterol in fried tuna was due to its migration into frying oil. This study indicated that cooking and microwave heating are the better processing methods to retain the health beneficial ω-3 fatty acids in comparison to frying and canning.

Antioxidative effects of Brassica juncea and Moringa oliefera prepared by different processing methods

“…The phenolic content was found to be enhanced significantly (p<0.001) by frying. Frying is believed to enhance the release of these active constituent (Stephen et al 2010). Microwave cooking reduced the phenolic content significantly (p<0.001) compared to control.…”

Effects of brine concentration on lipid oxidation and fatty acids profile of hot smoked tuna (Thunnus albacares) stored at refrigerated temperature

“…The content of PUFA, EPA and DHA decreased after smoking for all samples regardless of the brine concentration. The loss of health beneficial ω-3 fatty acids, EPA and DHA was reported in skipjack tuna subjected to different types of heat processing (Stephen et al 2010). The losses were higher with canning followed by frying, while cooking and microwaving heating was found to induce minimum losses.…”

Effect of different cooking methods on proximate and mineral composition of striped snakehead fish (Channa striatus, Bloch)

“…The various cooking methods invariably affect the nutritive value of fish and especially vitamins, flavour compounds and polyunsaturated fatty acids. The effects of different cooking methods on proximate and mineral composition of several fish species have been reported Gokoglu et al 2004;Kucukgulmez et al 2006;Rosa et al 2007;Weber et al 2008;Stephen et al 2010). Early developments in the field of nutrition predicted that certain substances, important for the proper functioning of the human body, are lost during cooking of foods.…”