Influence of secondary packing on the freezing time of chiken meat in air blast freezing tunnels

Behavior of the effective heat transfer coefficient and global thermal resistance in freezing of fruit juice model solutions in cylindrical packages

“…In this situation, the cooling air came in direct contact with the side of the two materials (plastic and metal), and the differentiation in the freezing time is primarily due to the greater ease of the metal in conducting heat compared to the plastic. Santos et al (2008), in a study with cooling and freezing of cuts of chicken in convective tunnels observed reductions of up to 45% in the freezing time of the products when using metallic mesh boxes compared to carton boxes.…”

“…According to Carson (2006) the conductivity of the ice is about four times higher than the liquid water. Also, according to Santos et al (2008) the heat resistance to heat conduction is inversely proportional to the thermal conductivity of the material.…”

“…That with low thermal resistance would be of interest since it allows faster heat exchange between the packaging material and the food. According to Santos et al (2008) it is difficult to decompose the different heat transfer resistances quantitatively during freezing. This is due to the complexity of the interfaces between the product and the packaging, the gap between the primary and secondary packaging, as well as the thermal contact resistances.…”

“…The process of freezing is considered to be of great interest for industrialized food, as it provides long term food conservation, maintaining most of its original characteristics, adding value to the food and contributing to loss reduction (Pereira et al, 2017). However, food freezing is a phase change heat transfer problem, with consequent changes in properties such as specific heat, enthalpy, and thermal conductivity, during the conversion of water into ice (Jie et al, 2003;Santos et al, 2008). The process does not happen at a constant temperature, but over a temperature range depending on the food composition and structure, its physical geometry, initial freezing temperature, and operational conditions (American Society of Heating Refrigerating and Air Conditioning Engineers, 2006).…”

“…Therefore, accurate knowledge of the heat transfer coefficients and the understanding of the thermal resistance created by the packaging material are essential in order to obtain a reliable prediction. However, these parameters are often too complex to be estimated under industrial processing conditions such as in a freezing tunnel (Amarante & Lanoisellé, 2005;Santos et al, 2008).…”