Study of the critical ambient temperatures impact on sweetened condensed milk

Abstract

The purpose of research is to study the impact of critical high-positive and low-negative environmental temperatures on the thermodynamic parameters of sweetened condensed milk (SCM), packaged in cans placed in transport containers. Objectives: determination of the values of average volumetric temperatures of SCM depending on the type of thermal effect; establishing the influence of the location of the product in the transport package on the average heating/cooling rate of the food system; identification of moisture crystallization criteria values. The object of the study is SCM, packed in tin cans, which were placed in transport packaging. The average volume temperature was measured thermographically using a logger. 4 cycles of thermal exposure were used, °C: [+5↑+50↓+5], [+5↑+50↓–50↑+5], [+5↓–50↑+5], [+5↓– 50↑+50↓+5]. For the range of 100 °C, an almost 2-fold increase in the average speed (1.6–2.6 °C/h) was established when heating [–50↑+50] relative to the average speed (0.8–1.3 °C/h) during cooling [+50↓–50], which is determined by the state of each component of the condensed milk-sugar system at a specific temperature point. At [+5↑+50↓+5] or [+5↓–50↑+5] for the central cans of the middle row, the duration of exposure was shorter (58 h 28 min 48 s and 115 h 19 min 12 s) than for the cans from the top row (78 hours 25 minutes 00 seconds and 124 hours 06 minutes 24 seconds). At [+5↑+50↓–50↑+5], the longest process duration was observed in the middle row consumer packaging. For the same tin, the shortest duration was revealed when exposed to temperatures in the opposite order. In the heating-freezing cycle, a decrease in the temperature of nucleation and phase transition was noted for the central and peripheral positions in consumer packaging and a decrease in the indicated thermodynamic characteristics in consumer packaging within the group for the top row, but an increase – for the middle. In the freeze-heat cycle in consumer packaging within a group package, a classical model of freezing was observed with a decrease in the temperature of nucleation and phase transition.