The Hydrolysis of Pigment-Protein Phycoerythrin by Bromelain Enhances the Color Stability
Yifei Sun,
Yuanmeng Cui,
Ruhua Wang,
Junrui Ma,
Haili Sun,
Lei Cheng,
Rui Yang
Affiliations
Yifei Sun
State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science & Technology, Tianjin 300457, China
Yuanmeng Cui
State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science & Technology, Tianjin 300457, China
Ruhua Wang
State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science & Technology, Tianjin 300457, China
Junrui Ma
State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science & Technology, Tianjin 300457, China
Haili Sun
State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science & Technology, Tianjin 300457, China
Lei Cheng
Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology & Business University (BTBU), Beijing 100048, China
Rui Yang
State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science & Technology, Tianjin 300457, China
Phycoerythrin (PE) is a natural protein–pigment complex with a strong pink color, but it is sensitive to thermal and light variations. In this study, PE was extracted from Porphyra haitanensis in a yield of 0.2% (w/w). The phycoerythrin hydrolysates (PEH) (3–10 kDa) were prepared by enzymatic hydrolysis of PE with bromelain (8000 U/g) at 47 °C for 30 min, with a degree of hydrolysis (DH) of 11.57 ± 0.39% and a color degradation rate of 7.98 ± 0.39%. The physicochemical properties of PEH were evaluated. The UV and fluorescence spectra indicated that bromelain changed the microenvironment around phycoerythrobilin (PEB). The infrared spectrum revealed that the bromelain hydrolysis increased the α-helix content of PEH. The scanning electron microscope showed that bromelain destroyed the dense and smooth structure of PE, resulting in irregular porous structures. The radical scavenging activities of DPPH and ABTS of PEH were increased relative to that of PE (p p < 0.05). This study provides a potential scheme for overcoming the sensitivity of PE to thermal and light variations and facilitates PEH as a natural colorant ingredient in food and pigment applications.
