Optimization of carbonic maceration pre-treatment and drying conditions in full and semi dried capia pepper production and examination it's effects on storage stability of the products

Capia pepper is the most produced pepper variety in our country in terms of quantity. In the food industry, it is used in many ways such as pickled, paste, canned, sauce and dried. While production quantity and types of dried fruit and vegetables is continuously increasing, the high amount of energy and prices spent in drying of foods have made more attractive the alternative systems and pre-treatments that shorten the drying time. Within the scope of this thesis study, fully and semi-dried capia peppers having different moisture contents were produced by carbonic maceration (CM) pre-treatment as a new technique that has not been used before in drying of capia peppers. In order to determine the optimum values for drying and CM pre-treatment conditions, the process parameters were optimized using the response surface methodology (RSM). The drying rate, red color (a*), browning index (BI) and antioxidant activity were selected as responses which have been deciced to involve in the model by backward elimination method. No significant difference was detected between the L*, a* and chroma values of fully dried capia peppers with CM pre-treatment and the values measured in fresh peppers (p>0.05). In semi-dried capia peppers, the same effect was seen only at a* value; there was no statistically significant difference in other values (p>0.05). Total color difference (ΔE) and browning index (BI) values in both fully and semi-dried capia peppers were positively affected by CM pre-treatment and were found to be lower than the control groups (p≤0.05). The rehydration rate of fully dried capia peppers subjected to CM pre-treatment were found statistically higher than control groups (p≤0.05). No significant difference was detected in terms of rehydration rate for semi-dried products (p>0.05). In terms of skin resistance and elasticity, which are texture parameters, CM pre-treatment did not create a statistically significant difference in fully dried capia peppers, but skin resistance values in semi-dry capia peppers were found to be lower than the control groups (p≤0.05). Among chemical properties, CM pre-treatment had a positive effect in the amounts of total phenolic substance, ascorbic acid and total carotenoid besides antioxidant activity for the of fully dried capia peppers and the values for these properties were found to be higher than the control groups (p≤0.05). Similar effects were observed in semi-dried capia peppers in terms of these values except antioxidant activity. During the storage period lasting for 6 months, fully dried capia peppers subjected to CM pre-treatment showed better results than the control groups in terms of total color difference, rehydration rate, total phenolic, total carotenoid, capsanthin and total aerobic mesophyll bacteria count values (p≤0.05). During the storage period of semi-dried capia peppers, it was determined that CM pre-treated capia peppers had superior qualities than the control groups in terms of rehydration rate, ascorbic acid and yeast-mold number values (p≤0.05). The ascorbic acid, total phenolic, total carotenoid and capsanthin amounts of fully dried capia peppers whose storage temperature was 4°C were found to be higher than those stored at 20°C. For semi-dried capia peppers, Hue angle, rehydration rate and ascorbic acid, total carotenoid and capsanthin amounts are the properties that were negatively affected from the increase in storage temperature. When packaging methods were evaluated, total carotenoid and capsanthin contents of capia peppers during the storage process differed according to packaging methods (p≤0.05) and it was determined that the packaging method providing the highest pigment content was vacuum packaging, while the lowest pigment content was found in normal packaging. As the storage process progressed, the Hue angle values as well as the amounts of ascorbic acid, total phenolics, total carotenoids and capsanthin decreased (p≤0.05). While yeast and mold growth has not been observed in fully dried capia peppers during storage, an increase in yeast and mold number was recorded throughout storage starting from the second month. According to optimized process parameters; the optimum drying temperature for capia pepper drying was determined as 79.9°C. The optimum conditions for CM pre-treatment were found as 30.5°C temperature, 1 bar pressure and 4 hours waiting time. Drying of capia peppers after CM pre-treatment resulted in a 17.3% reduction in drying time. According to the study results, CM pre-treatment reduced the drying time of capia pepper and had positive effects on some physical, chemical and microbiological properties. Thanks to these advantages, it can be concluded that CM pre-treatment is promising in drying of capia pepper. It is recommended to make improvements in the system and continue research in order to convert the system from a batch system to a continuous system and to increase it to larger capacities.