Supplemental linseed oil and antioxidants affect fatty acid composition, oxidation and colour stability of frozen pork
The aim of this study was to evaluate the influence of dietary linseed oil and antioxidants on the quality of fresh and frozen pork neck stored at -20 °C for six and 12 months. Polish Landrace x Duroc pigs were fed a standard diet (C), a diet supplemented with 3% linseed oil (L1), or a diet with 3% of linseed oil, 1 mg organic selenium (SE)/kg, and 100 mg vitamin E/kg (L2). Chemical components, fatty acid profile and vitamin E content were determined in the fresh meat. Colour, pH and change in the profiles of certain volatile compounds (alcohols, aldehydes, ketones, and esters) were monitored during frozen storage. An electronic nose technique, which was based on ultra-fast gas chromatography, was used to evaluate changes in the profiles of the volatile compounds. After six months of frozen storage, oxidative processes were slower and similar in groups L1 and L2, but less so in meat from C. In pork that was stored for six months, lipid oxidation was not affected by supplementation only with linseed oil (L1). After 12 months of frozen storage, a reduced rate of increase in alcohols, aldehydes and ketones was observed in pork from L2 relative to L1 and C. Lipid oxidation processes in long-stored frozen pork neck were inhibited by the addition of antioxidants to L2. However, a total colour change (ΔE*) of the pork from L1 and L2 was found during storage, which might influence consumers’ decisions to purchase the product.
Keywords: colour, fatty acids, freezing, meat quality, volatile components