Stability of Ceylon spinach (Basella alba L.) seed protein extract and its effect on the microbiological, chemical and sensory quality of sturgeon fillets stored at 4 degrees C

The antimicrobial activity and preservative effect of Ceylon spinach (Basella alba L.) seed protein extract on sturgeon fillets stored at 4 degrees C were investigated in this study. The results showed that Ceylon spinach seed protein extract (CSSPE) had inhibitory effect on 33 microorganisms, including 1 fungus and 32 bacteria (25 gram-negative bacteria and 7 gram-positive bacteria). In addition, CSSPE inhibited bacterial growth (total viable counts, Pseudomonas, Aeromonas and psychrotrophs), suppressed ATP degradation and retained good-quality characteristic of sturgeon fillets stored at 4 degrees C. The shelf life of 30 mg/mL CSSPE treated fillets was around 7 days according to the results of total viable count, which extended around 2 days compared with that of the control group. The stability of CSSPE was also evaluated, and the results showed that CSSPE had excellent stability under UV irradiation, monovalent metal ions, surfactant and protease treatment. CSSPE could maintain high antimicrobial activity within the range of pH 2-8 and 12-13 and its thermal denaturation temperature was 70 degrees C. The results suggested that CSSPE had the potential to be developed as a preservative for aquatic products.