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Freezing tilapia by airblast and liquid nitrogen – freezing point and freezing rate
Author(s) -
CHEN YAULING,
PAN BONNIE SUN
Publication year - 1995
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1995.tb01368.x
Subject(s) - liquid nitrogen , differential scanning calorimetry , freezing point , tilapia , congelation , nitrogen , chemistry , freezing behavior , materials science , fish <actinopterygii> , analytical chemistry (journal) , zoology , mathematics , chromatography , fishery , biology , thermodynamics , physics , organic chemistry , statistics , fear conditioning , conditioning
Summary Processing data was obtained for the freezing of tilapia meat. The initial freezing point of tilapia meat was measured by differential scanning calorimetry (DSC), and also by measuring the centre temperatures of meat chunks during cooling. the freezing point was −1.03°C by DSC, and between −0.81 and −0.90°C by the cooling method, determined at the point where the standard deviation of the mean temperature was close to zero, i.e. a minimum. Tilapia chunks, 0.95 to 1.45 cm thick, were frozen in an airblast freezer at −7, −20 and −36°C, and in a liquid nitrogen freezer at −87 and −128°C. Freezing rate, defined as the half thickness of a meat chunk divided by the time for the centre temperature to decrease from 0 to −5°C, was 0.09 cmh −1 at −7°C. At freezing temperatures of −20, −36, −87 and −128°C, the rates were respectively 4, 19, 158 and 331 times faster than that at −7°C, and correlated with freezing temperature ( r = 0.99) regardless of the freezing method.