An insight on the relationship between food compressibility and microbial inactivation during high pressure processing

Abstract

This paper investigates the effect of high pressure liquid food compressibility on S. cerevisae inactivation. Honey with various adjusted sugar with different values of compressibility was selected as a model food. S. cerevisiae cells in different honey concentrations (0-80°Brix), 600 MPa (at ambient temperature) showed an increasing resistance to inactivation with increasing °Brix. D-values of S. cerevisiae at 200, 400 and 600 MPa, for 20 min/80°Brix were 136.99 ± 7.97, 29.24 ± 6.44 and 23.47 ± 0.86 min, respectively. These D-values resulted the Z _p -value of 526 ± 39 MPa. A significant correlation (p < 0.05) of cell reduction, °Brix and compressibility was found. Cell reduction in high pressure-treated samples varied linearly with °Brix suggesting that the baroprotective effect of the food was not solely due to sugar content, but also due to its compressibility. This research could have significant implications on the success of HPP (high pressure processing) preservation of foods containing high sugar content.

Keywords: Compressibility; High pressure processing; Honey; Microbial inactivation; Saccharomyces cerevisiae; Sugar content.

Fig. 1

Compressibility of honey solution at different pressure levels as a function of sugar concentration (°Brix). Data were taken and reassembled from Min et al. (2010)

Fig. 2

S. cerevisiae cell survivors in honey (80°Brix) subjected to HPP (ambient temperature) at (i) ◊ = 200; □ = 400 and Δ = 600 MPa. The error bars are standard deviation (n = 3)

Fig. 3

Comparison of log reduction of S. cerevisae after HPP treatment (600 MPa for 2 and 30 min) and thermal treatment (55 °C for 10 min) for different sugar concentrations. Error bars represents standard deviation with n = 3

Fig. 4

Effect of compressibility and °Brix on the inactivation of S. cerevisiae subjected to HPP at 600 MPa for 2 and 30 min