EVALUATION OF SOME QUALITY CHARACTERISTICS OF BELL PEPPER DURING FROZEN STORAGE
Project no. 1400 · Status: Kapanmış · 2017
Summary
In this study quality changes in California Wonder (C. annuum L., var. grossum) green bell pepper treated with water blanching, individual quick freezing (IQF) at different process parameters (control, 75°C-2 min, 75°C-2 min and 90°C-65 s) was aimed to be investigated during frozen storage at -18°C for 12 months. For this purpose, after determining the moisture and protein contents of the samples, polyphenol oxidase enzyme activity, ascorbic acid content, chlorophyll content, texture and colour measurements, sensory analysis were performed at 0, 2, 4, 6, 8, 10 and 12 months and effects of this process parameters on shelf life and product quality were investigated. The moisture content of the green bell pepper was determined as, 93.73%, the protein contents were 13.07%, 12.41%, 12.43% and 12.29% as dry matter for control, 75°C-2 min, 75°C-3 min and 90°C-65 s parameters, respectively. As frozen storage time increased, polyphenol oxidase enzyme activity increased significantly, activities were determined to be statistically different for each process parameter and at the end of 12 months the activities from highest to lowest were determined as control, 75°C-3 min, 75°C-2 min and 90°C-65 s blanched samples. Ascorbic acid and chlorophyll contents decreased significantly as the frozen storage time increased, at the end of 12 months ascorbic acid content of the control sample was significantly lower than the blanched samples and no significant difference was determined between the blanched samples. Chlorophyll content loss of control, 75°C-2 min, 75°C-2 min and 90°C-65 s blanched samples at the end of 12 months were determined as 21.93%, 11.33%, 16.87% and 10.12%, respectively. No significant difference was determined in hardness of the samples throughout the frozen storage time by instrumental texture measurement, the control sample was significantly harder than the blanched samples, no significant differences between the blanching parameters were determined and elasticity values were not affected by frozen storage time. Instrumental colour analysis showed that, at the end of 12 months, 90°C-65 s blanched sample was determined to be the sample with the highest L*, -a* and hue angle values and the lowest b*, total colour change and browning index values and the sample that preserves its colour the best. As a result of sensory evaluation, although no significant differences were determined between the 75°C-2 min and 90°C-65 s blanched samples, the higher colour and flavour scores were obtained for 90°C-65 s blanched samples. When the results were evaluated, 90°C-65 s blanched sample was determined as the sample which has the longest shelf life and the best product quality, received higher sensory evaluation scores than the samples of other process parameters.