Comprehensive Evaluation of Fresh-Keeping Performance of Refrigerators based on the Changes of Quality of Spinach

At present, scientific and standardized evaluation methods and standards for fridge preservation effect were lacked in the home appliance industry. In this study, through multidimensional analysis and decay law analysis on the quality of refrigerated food, the fresh-keeping performance of refrigerators was evaluated. Spinach, as a typical refrigerated food, was analyzed in terms of physicochemical and sensory quality during storage. The effects of time (0, 2, 4, 6, 8 d) and storage areas were investigated. Results showed that, weight loss rate (X₁), total color difference (X₂), loss of chlorophyll content (X₃) and loss rate of vitamin C content (X₄) were the main physichemical characteristics of spinach freshness. Principal component analysis extracted two principal components, whose contributions were 54.694%, 29.732%, respectively. Their cumulative contribution reached 84.426%. The evaluation formula of the physichemical properties was:F=0.648×(0.572X₁+0.075X₂+0.559X₃+0.595X₄) +0.352×(0.229X₁+0.883X₂-0.356X₃-0.064X₄). Multivariate statistical analysis revealed that gloss (S₁), hardness (S₂), green flavor (S₃) and overall impression (S₄) were the major indicators of sensory quality. The evaluation formula of sensory characteristics was P=(0.352, 0.101, 0.049, 0.498)×(S₁, S₂, S₃, S₄)×(95, 85, 75, 65, 30) T. A comprehensive evaluation system was established based on multivariate statistical analysis method, with the formula for freshness assessment was G=P/F. This study established a solid and comprehensive evaluation system, which provided technical support to effectively assess the fresh-keeping performance of refrigerators.