Antioxidative effect of crackling hydrolysates during frozen storage of cooked pork meatballs

The effect of acid (CAH) and enzymatic (CEH) hydrolysates prepared from pork cracklings on the oxidative stability of frozen pork meatballs was investigated. Meatballs were stored at −18 °C for 180, 270 and 360 days during which time peroxide value (PV), TBARS, profiling sensory analysis and cholesterol oxidation products (COPs) were determined. The oxidation products of cholesterol, such as epimers 7-hydroxy, 5,6-epoxy, 7-keto, triol and 25-hydroxy, after transesterification and SPE fractionation, were detected by capillary gas chromatography. CAH and CEH possessed similar antioxidant efficacy. Inhibition activity of cracklings hydrolysates against PV was 38–45%, and against TBARS was 30–39%. The antioxidant properties of CAH and CEH against the oxidation of lipids were poorer than that of BHT. The addition of hydrolysates changed sensory profiles and had a significant (P<0.05) effect on the taste and odour of meatballs. The total COPs in all meatballs increased during storage. 7-Keto-cholesterol was the dominant oxysterol in fresh samples. After 360 days of storage, levels of oxysterols in samples treated with hydrolysates were about 20% lower than that of the control sample. The most toxic derivative, triol-cholesterol, was detected at the lowest level in samples treated with hydrolysates. The protection of BHT against cholesterol oxidation was poorer than that of CEH.