Optimization of Black Garlic Extract Curing Conditions for Mackerel Using Response Surface Methodology

We examined the quality characteristics of obtaining the optimal curing conditions for black garlic extract (BGE) added mackerel by using response surface methodology (RSM). The condition of RSM was included in 13 experimental points using two dependent variables: concentration of BGE (2.6～12.5 brix, X1) and curing time of BGE (17.58～102.42 min, X2). An assessment was conducted with four replicates on three independent variables: volatile basic amine (VBN, Y1), thiobarbituric acid (TBA, Y2), and shear force (Y3). The minimum content of VBN was 1.625 mg% at 3.17 brix, for 80.5 min. This was obtained when the BGE concentration was lower and the curing time was longer. The content of the TBA was 3.13～12.24 MA mg/kg at experiment range and the stationary point was at saddle point. Therefore, by using ridge analysis, the minimum point of TBA was 2.414 MA mg/kg at 3.5 brix for 84.4 min. The truth coefficient of the BGE concentration and curing time were 2.9 brix and 75.1 min, respectively, with a shear force (120.764 cm/kg2) shown at maximum point. The optimum Hunter color range was estimated from the lowest TBA value. The optimum range of the L color was 39.16～40.26, a and b color were 4.40～4.88 and 12.35～13.20, respectively.

Key words : black garlic extract, response surface methodology, mackerel, TBA