Abstract: In order to extend the shelf-life of chilled beef and establish a predictive model for the determination of the shelflife, we developed and optimized an effective composite preservative containing antimicrobial peptides derived from casein, chitosan, nisin, tea polyphenols and clove essential oil using a U16(84) uniform design. Total volatile basic nitrogen (TVB-N) value, pH and total viable count were used as response variables. The results showed that the optimal combination was determined as 22.5 g/L chitosan, 0.15 g/L nisin, 9.7 g/L antimicrobial peptides derived from casein, 1.5 g/L tea polyphenols and 13.0 g/L clove essential oil. Compared with the control group, the shelf-life of chilled beef treated with the optimal composite preservative and stored at (4 ± 1) ℃ was extended by over 25 days. The interaction between antimicrobial peptides and nisin, tea polyphenols or clove essential oil, and between nisin and tea polyphenols had a significant effect on the change of TVB-N content (P < 0.01). Total viable counts of chilled beef treated with this composite preservative as a function of storage temperature (?1, 2 and 6 ℃) were fitted with the Arrhenius equation with the coefficients of determination greater than 0.91. The shelf-life (SL) prediction model developed was as follows: SL = 2.75 × 10-9 × exp (6 567.2/T). The actual shelf-life of chilled beef at 2, 4 and 6 ℃ was 61, 53 and 47 d, respectively and the relative error between the actual and predictive values less than 6%, suggesting that the model can effectively predict the shelf-life of chilled beef at ?1–6 ℃.

Key words: chilled beef, antimicrobial peptides derived from casein, composite preservative, shelf-life, prediction model