Investigation of the effect of sous-vide cooking technique on the texture and physicohemical properties of squid (Loligo vulgaris) muscle

In this thesis, it is aimed to investigate the effect of Sous-vide cooking technique on texture and physicochemical properties of squid (Loligo vulgaris) muscle. Pre-treated and cleaned squid were packed under vacuum after they were placed in vacuum packaging. Packaged squid samples were cooked in the water bath of sous-vide cooking equipment by applying 2 different cooking temperatures (60°C and 80°C) and 3 different cooking times (30, 60 and 120 minutes). After cooking, the samples were immediately cooled in ice water. Raw squids without heat treatment were used as control group. Physicochemical analysis of all samples were performed. According to the results of the analysis, it was determined that the cooking temperature has a significant effect on the cooking loss value. More cooking loss was detected by cooking squid samples at 80°C than at 60°C. The increase in cooking temperature resulted in an increase in cooking loss. Cooking temperature and cooking time have also been found to have significant effects on pH values. As the cooking temperature increased, the pH value increased. While the highest pH values were observed in samples cooked for 60 minutes, the lowest value was observed in 30 minutes of cooking. The cooking process of the samples cooked at 60°C for 30, 60 and 120 minutes and 80 ° C for 30 minutes caused a significant decrease in the pH value. The higher the cooking temperature, the higher the free amino acid value was observed. The highest free amino acid value was observed in samples cooked for 120 minutes. Compared to the measurements made in raw samples, It was observed that the amount of free amino acids were higher than the products cooked for a shorter time. Since color is an important quality feature that constitutes the first impression of the consumer on food, the color values of cooked squid were examined and L *, a * and b * values were measured. While the cooking process changed the color values, but cooking at different temperatures did not have a significant effect on the L * value, it caused a decrease in the a * value and an increase in the b * value as a result of the temperature increase. It was determined that the cooking time had no significant effect on the L * and a * values, and it was found that it had a significant effect on the b * value and the highest b * value was observed in 60 minutes of cooking time. In our study, in addition to the hardness, springiness, adhesiveness, cohesiveness, gumminess and chewiness properties of the squid meat, the required maximum force measurement was performed with the cut test. As per the results of analysis made, it was determined that the cooked squid was softer than the raw squid, and the hardness of the samples cooked at a lower temperature was lower and the lowest hardness levels were obtained during the longest cooking times. The most suitable values in terms of adhesiveness and springiness values were detected at 60°C temperature and 60 minutes cooking time. It was determined that the cohesiveness values increased with temperature, but the cooking time had no effect. It was observed that the gumminess value was significantly affected by the cooking process and the lowest values were observed in squid cooked in 120 minutes. The low chewiness values indicate ease of chewing, and according to the results obtained, chewiness values of the samples cooked at high temperatures were higher, the samples cooked at 60°C were observed to have better textural properties. A significant decrease observed in the cutting force values after the cooking process, an increase was observed in the cutting force at high cooking temperature and the cutting force values increased with the increasing cooking time. According to the results of the sensory analysis, the squid cooked at 60°C received more appreciation and the highest score was seen in the samples cooked for 60 minutes. As a result of the study, sous-vide cooking method has been found to be effective at softening hard textured squid meat. Evaluation of the textural analysis of squid meat results has been determined that the optimal cooking temperature and time 60°C and 60 minutes.