Effect of Cooking Methods on Quality and Shelf Life of Ready-to-Eat Cooked Betong Chicken Meat during Refrigerated Storage

Abstract

Betong chicken is an important native breed of chicken in the 3 southern border provinces of Thailand (Pattani, Yala and Narathiwas). It is popular among Thai and foreign consumers. Appropriate cooking methods can help maintaining the quality of ready-to-eat cooked Betong chicken meat for a long time during refrigerated storage. The sous vide technique is a cooking method by packing food in a vacuum condition and heating it with a temperature lower than 100°C for a long period to maintain the quality of food. The purpose of this research was to study the effect of cooking methods on the quality and shelf life of ready-to-eat cooked Betong chicken meat during refrigerated storage. In this study, two cooking methods were used including the boiling method (the control) and the sous vide method. For the boiling method, Betong chicken meat was boiled at 100°C for 20 minutes and then rapidly cooled down by immersion in iced water and stored in a Nylon/LLDPE plastic bag under atmospheric condition. For the sous vide method, Betong chicken meat vacuum packed in a Nylon/LLDPE plastic bag was heated at 60°C for 3 hours and then rapidly cooled down by immersion in iced water. Both types of ready-to-eat cooked Betong chicken meat were stored at a refrigerated condition (4±2 °C) for 20 days. From the study of product quality during storage, it was found that physical, chemical, microbiological and sensory qualities of both types of ready-to-eat cooked Betong chicken meat were significantly different (p<0.05). The ready-to-eat cooked Betong chicken meat cooked by the sous vide method showed less changes in texture, pH, thiobabituric acid value and total microbial load than the control chicken meat throughout the storage period. However, it had higher scores for appearance, color, texture and overall liking than the control chicken meat. The ready-to-eat cooked Betong chicken meat cooked by the sous vide method and the control chicken meat had total microbial counts exceeding the microbiological limit when stored for 20 and 10 days, respectively. This research suggested that the sous vide method was a cooking method capable of preserving the quality of ready-to-eat cooked Betong chicken meat during refrigerated storage longer than the boiling method.