Comparison of the quality characteristics of abalone processed by high-pressure sub-zero temperature and pressure-shift freezing

This study investigated the effects of high pressure sub-zero temperature (HPST) and pressure-shift freezing (PSF) on the quality characteristics of abalone. Each process was conducted within 0.1–200 MPa. HPST caused high drip loss relative to the control, whereas drip generation was effectively prevented by PSF at 150 MPa. The shear force of abalone treated by HPST exhibited a significant decrease with increasing pressure, whereas abalone treated by PSF maintained shear force values similar to the control. With respect to color, HPST resulted in high redness (a*) without changes in lightness (L*) or yellowness (b*) relative to control. The a* and b* of PSF-treated abalone were similar to control, although low L* was observed in PSF-treated abalone. Regardless of the processing methods, increasing pressure levels tended to decrease the aerobic colony count (ACC) of abalone. Consequently, the results suggested that PSF effectively minimized the quality damage caused by the abalone freezing process and that 150 MPa was the optimal condition for PSF for abalone. Pressure-shift freezing has been recognized as the most rapid freezing technique. Currently, high pressure low temperature (HPLT) processing is adopted by means of long time storage of biomaterials. Nevertheless, one of the problem to apply these technique in actual industry is that the materials have to be kept at normally 200 MPa at which the materials can cooled down to around − 20 °C. Based on this study, it is possible to reduce the processing pressure level (~ 100 MPa) which would provide a practical advantage of HPLT processing as well as industrial applicability.