FOOD SCIENCE ›› 2019, Vol. 40 ›› Issue (19): 249-255.doi: 10.7506/spkx1002-6630-20181017-183

• Packaging & Storage • Previous Articles     Next Articles

Preparation and Properties of Lysozyme and ε-Polylysine Hydrochloride Composite Coating

LI Qiuying, ZHANG Dongdong, WANG Siwen, ZHONG Keli, XU Yongxia, LI Yingchang, SUN Tong, LI Jianrong   

  1. (1. National & Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, College of Food Science and Engineering, Bohai University, Jinzhou 121013, China; 2. College of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121013, China)
  • Online:2019-10-15 Published:2019-10-25

Abstract: In the present study, a chitosan-pullulan composite coating (CS-PUL-A) containing antibacterial agents (3 mg/mL lysozyme and 1.8 mg/mL ε-polylysine hydrochloride) was prepared, and its properties were compared with those of its counterpart without antibacterial agents (CS-PUL). The results showed that addition of antibacterial agents improved the toughness and gas and water vapor barrier properties but had little effect on the tensile strength and light transmission of the composite coating. In addition, CS-PUL-A had stronger antibacterial activity against Pseudomonas fluorescens (one of the dominant specific spoilage organisms in fish) than did CS-PUL, and the activity appeared after cultivation for 12 h. Compared with CS-PUL, CS-PUL-A could result in increased leakage of intracellular nucleotides and electrolytes and subsequently higher conductivity of the cell suspension, indicating that CS-PUL-A more severely damaged the cell membrane integrity and permeability. The coating treatment also reduced the activity of alkaline phosphatase in the suspension. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that CS-PUL mainly affected small proteins, while CS-PUL-A affected both small and large proteins. Scanning electron microscopy further confirmed the damage to bacterial cells caused by CS-PUL-A. In summary, CS-PUL-A exerted better physicochemical properties and antibacterial properties than CS-PUL and could be potentially used in food preservation.

Key words: polysaccharide, coating, lysozyme, ε-polylysine hydrochloride, antibacterial activity

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