关键词: 差示扫描量热法, 冰点, 变性温度, 变性热焓, 比热容

Abstract:

The study was intended to investigate comparatively the thermal properties of muscles from 5 different freshwater
fish (Megalobrama amblycephala, Ctenopharyngodon idellus, Pelteobagrus fulvidraco, Lateolabras janopicus and Siniperca
chuatsi) by differential scanning calorimetry (DSC), including moisture content, freezing point, denaturation temperature,
denaturation enthalpy and specific heat capacity. Results showed that the freezing points of the five fish ranged from −0.57 to
−0.10 ℃; the onset temperature of decalescence peak around 50 ℃ ranged from 37.00 to 41.57 ℃, the conclusion temperature
ranged from 60.47 to 62.33 ℃, and the denaturation enthalpy ranged from 1.680 0 to 2.499 7 J/g. The onset temperature of
decalescence peak around 70 ℃ ranged from 66.33 to 71.13 ℃, the conclusion temperature ranged from 73.60 to 82.20 ℃, and
the denaturation enthalpy ranged from 0.418 0 to 0.512 2 J/g; the specific heat capacity ranged from 1.658 0 to 3.862 3 J/(g·K).
As demonstrated by this study, among the five species examined, freezing point and moisture content of Megalobrama
amblycephala were relatively lower; denaturation temperature and denaturation enthalpy of Ctenopharyngodon idellus
myosin and Siniperca chuatsi actin were relatively higher, which means that they had higher protein stability. Moreover, the
specific heat capacity of fresh fish was higher than that of frozen fish; the specific heat capacity of processed fish was higher
than that of the unprocessed one.

Key words: differential scanning calorimetry(DSC), freezing point, denaturation temperature, denaturation enthalpy, specific heat capacity