Content and change after heating of imidazole dipeptide, a functional element of the breast of ‘Hakata Jidori’

Imidazole dipeptide (IDP) is abundant especially in chicken breast among the skeletal muscles of animals, and functions to facilitate the recovery from fatigue with its antioxidation effect, improve the memory function by boosting cerebral blood flow in the posterior cingulate cortex, and so on. For the purpose of enhancing the brand name of ‘Hakata Jidori’ we analyzed the IDP content in its breast, and studied the change in the IDP content through heating while envisioning the development of processed products. The results show that the average IDP content in the breast of ‘Hakata Jidori’ was 1,761 mg/100 g, significantly larger than that of commercial broiler chicken: 1,230 mg/100 g (P < 0.01). It was also found that the IDP contents in the breast of ‘Hakata Jidori’ during the hot period (daily mean air temperature: 26.7℃) and the cold period (daily mean air temperature: 6.0℃) are not different from that in the suitable period (daily mean air temperature: 20.2℃)． The IDP content of ‘Hakata Jidori’ whose feeding period is ordinary and 84 days was 1,869 mg/100 g, while those of ‘Hakata Jidori’ whose feeding periods are 95 days and 103 days were 2,173 mg/100 g and 2,349 mg/100 g, respectively, indicating significant increases (P < 0.05). The IDP content of unheated ‘Hakata Jidori’ was 1,882 mg/100 g, while that of steamed chicken was 1,623 mg/100 g, indicating a significant drop (P < 0.05), but the IDP content of grilled chicken was 2,076 mg/100 g and that of deep-fried chicken was 2,323 mg/100 g, showing significant increases (P < 0.05). It was revealed from these results that the breast of ‘Hakata Jidori’ has a larger IDP content than that of commercial broiler chicken, and the IDP content increases according to the degree of grilling or deep-frying. Accordingly, it can be expected that sales channels will be expanded and processed products will be developed for ‘Hakata Jidori’ as food with health claims.