High‐pressure Differential Scanning Calorimetry (Dsc): Equipment and Technique Validation Using Water–ice Phase‐transition Data

Abstract

Understanding phase transition during high-pressure (HP) processing of foods is important both with respect to optimizing the process and improvement of product quality, but scientific information available in this area is very limited. In this study, the phase-transition behavior of water was evaluated using a HP differential scanning calorimetry (DSC). Tests were carried out under both isothermal pressure-scan (P-scan) and isobaric temperature-scan (T-scan) modes with distilled water prefrozen in the sample cell. P-scan was carried out at 0.3 MPa/min at two temperatures, -10 and -20C, and T-scan was carried out at 0.15C/min at two pressures, 0.1 and 115 MPa. The pressure-induced phase transition of water was accurately reproduced by the P-scan test. Ice melting latent heat during P-scan showed no significant difference ( P > 0.05) from the available reference data in literature. The relationship between P-scan tested (L m ) and reference latent heat was L m = 0.987 L (R 2 = 0.99, n = 6) suggesting a mean error less than 2%. T-scan mode was less appropriate and did not yield promising result. Measured values were less accurate than P-scan probably because of the influence of large heat capacity of sample cell. However, reliable and reproducible results obtained under P-scan mode suggested that the HP DSC can be used for the calorimetric determination of pressure-dependent water-phase transition in real food systems during HP freezing/thawing operations.

Differential Scanning Calorimetry

“…A high-pressure DSC was examined by Zhu et al (2004) for the evaluation of high-pressure phase-transition behaviour of pure water (in the melting mode). Two techniques (T-scan and P-scan) were used.…”

High-pressure differential scanning calorimetry: Comparison of pressure-dependent phase transition in food materials

“…Water was used for the validation of experimental system and technique as reported in Zhu, Bulut, et al (2005) because its phase transition under pressure is well known (Bridgman, 1912). Tylose is a food model material (hydroxymethylcellulose gel) with well-documented thermal properties (Cleland & Earle, 1984).…”

“…Modern calorimeters like differential scanning calorimeters (DSC) usually worked at constant pressure (mostly at atmospheric pressure) while temperature is changed as a working parameter. In the case of high pressure, however, this method does not work well due to large heat capacity of the vessels that is necessary to restrain pressure (Zhu, Bulut, Le Bail, & Ramaswamy, 2005). An alternative measure to overcome this difficulty is to make an HP calorimeter work at constant temperature and change pressure.…”

“…In the previous study, a HP DSC methodology was set up and validated for evaluation of HP dependent phase transition in pure water (Zhu, Bulut, et al, 2005) and pork muscle . The objectives of this paper were to extend the HP DSC study to evaluate the phase transition behavior in different types of food materials [Tylose, potato, Atlantic salmon (Salmo salar) as well as pork and pure water (Zhu, Bulut, et al, 2005;], and to compare the phase transition results among these materials.…”

“…The objectives of this paper were to extend the HP DSC study to evaluate the phase transition behavior in different types of food materials [Tylose, potato, Atlantic salmon (Salmo salar) as well as pork and pure water (Zhu, Bulut, et al, 2005;], and to compare the phase transition results among these materials.…”