THERMAL ANALYSIS OF FOOD PRODUCTS USING DIFFERENTIAL SCANNING CALORIMETRY (DSC)

Abstract

Intensity of changes during the freezing storage of frozen foods, depends on several factors. Changes of foods during freezing and thawing can be rapidly determined by scanning calorimetry (DSC). The aim of this study was to test the influence of scanning rate on the thermal properties of previously heat-treated food products (boiled apple), using the differential scanning calorimetry method. By increasing the scanning rate, significant changes (p<0.05) Tcon from -14,20 °C (rate 5 °C/min) to -15.57 °C (rate 15 °C/min) and Tcend (from -17.53 °C to -22.90 °C) were determined, and ΔTc increased from 3.33 °C to 7.33 °C. At the same time, the width of the melting temperature interval (ΔTm) increased from 7.80 °C to 12.87 °C. The glass transition temperature (Tgmid) ranged from -7.15 °C (rate 5 °C/min) to -6.60 °C (rate 15 °C/min). Based on the obtained results, it was found that the scanning rate during the DSC determination statistically significantly (p<0.05) influenced the measured values of the thermal properties of the tested heat-treated apple samples.
Keywords: DSC, food products, apple, frezing, thermal properties.