For the samples with combined treatment (ozone and lyophilisation), aw values were significantly affected by both factors concentration of ozone and its time of exposure. Those values increased significantly (P < 0.05) when ozone concentration and exposure time increased. The water activity (aw) of the combined samples ranged between 0.162 ± 0.005 and 0.268 ± 0.009. It is important to note that all samples had aw values lower than 0.6. This value is considered as the limit of growth for microorganisms in food (Leistner, 1992), as all bacterial species fail to grow at aw of less than 0.6 (Barreiro & Sandoval, 2006). Nevertheless, the moisture content increased when contact time of ozone increased, but it was found not to be significantly influenced by ozone concentration. Thus, samples from treatment trt-0.4/120 were noted to have a higher (P < 0.05) moisture content than samples from treatments trt-0.4/60 and trt-0.6/30. No significant differences were observed in samples that were ozonated for 10 and 30 min.On other hand, the mean rehydration percentage for the freeze-dried samples (trt-0) was 72.88 ± 1.28%. These results were similar to those reported by Babić et al. (2009) who found the highest rehydration percentages of 74.45 ± 8.95% in freeze-dried Broiler chicken meat.
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