Abstract:The application of ultrasound-assisted enzymatic extraction of gelatin from chicken lung was explored in this study. The structure of extracted chicken lung gelatin was investigated by ultraviolet spectroscopy, differential scanning calorimetry, circular dichroism, polyacrylamide gel electrophoresis, laser particle size distribution, scanning electron microscopy, etc. Its emulsifying property was also characterized. The yield of ultrasonic assisted enzymatic extraction was 30.08% based on the dry weight of lungs without impurity, which was 3.43 times compared with that of conventional hot water extraction. And the extraction efficiency increased by 2.15 times, while the thermal denaturation temperature slightly decreased to 90.22 ℃. The characteristic absorption peaks of chicken lung gelatin were observed at 229 nm in both extracted methods. The secondary structure of extracted gelatin using ultrasonic-assisted enzymatic extraction was more orderly with lower degree of random curling. The average particle size distribution of gelatin extracted by ultrasound-assisted enzymatic extraction was 396 nm, reduced by 13.7%. The gelatin molecules distributed by ultrasound assisted enzyme were mainly within 45 000 ~ 95 000, which suggested almost completely degradation into smaller molecular subunits. Obvious fragmentation was observed on their surface microstructures. Insignificant difference of emulsification was determined between two extracted gelatin samples. Therefore, ultrasound-assisted enzymatic extraction can significantly improve the extraction rate of gelatin and effectively shorten the production cycle. Chicken lung gelatin can also be used as an emulsifier in the food industry with a potential application prospect in the food field, which can further improve the added value of broiler by-products.
