Investigating the use of inulin as a cryoprotectant agent in fruit & vegetable and meat products with the effects of freezing – thawing methods and storage time

This thesis was carried out to investigate in detail the effects of using inulin powder obtained from Jerusalem artichoke as a cryoprotectant agent in fruit-vegetable and meat products on the food quality properties of different freezing and thawing techniques and storage time in order to reduce or prevent quality losses that are frequently observed in frozen food products. First, inulin powder cryoprotectant was transferred to the chicken nugget by adding to the formulation and also was transferred to the globe artichoke, sour cherry and beef meat by ultrasound assisted vacuum impregnation method. Then, each model food was frozen by static, airflow and individual quick freezing methods (IQF) and stored for six months. At the end of each month during storage, model foods were thawed by three different methods (microwave, 25 °C and 4 °C) and subjected to analysis of total dry matter amount, water activity, pH value, color difference value, hardness value, drip loss and ion leakage. In addition, ascorbic acid amount, polyphenol oxidase activity, total phenolic content and antioxidant capacity by DPPH and ABTS method in artichoke; pectin methylesterase activity, total phenolic content and monomeric anthocyanin content and antioxidant capacity analyzes by DPPH and ABTS method in sour cherry; cooking loss and TBARS analyzes were performed on beef meat and chicken nuggets. It has been determined that the fast freezing methods create smaller ice crystals with homogeneous distribution inside and outside the cell compared to the slow freezing method such as the static freezing system. Higher PPO and PME activity values were detected in the globe artichoke and cherry samples frozen with the static freezing system compared to the samples frozen with the IQF system. Inulin increased the water holding capacity of the model food samples and kept the color values and pH values more stable. It was found that the inulin-added artichoke samples had the highest ascorbic acid values. Also, more losses were determined in the amount of phenolic compounds in the globe artichoke samples thawed at room temperature. It has been found that microwave thawing provides a shorter time to thaw and generally reduces drip loss in foods. It was concluded that the use of inulin powder cryoprotectant obtained from Jerusalem artichoke and the use of rapid freezing and rapid thawing methods more effectively preserve the quality of the food during the storage period compared to other conventional freezing and thawing methods. It is expected that the findings and literature research will benefit the sector in improving the quality characteristics of product groups in which problems are common in the frozen food industry, resulting in heavy product loss, financial damage and food waste.