Biomass Feedstocks

Finite Element Method for Freezing and Thawing Industrial Food Processes

“…Frozen food products have been extensively appreciated by consumers because of being consistent with a modern lifestyle [ 45 , 46 ], where frozen food products experience an increasing demand of about 20% annually [ 47 ]. A freezing process includes three stages: (a) cooling the product from the initial temperature to its initial freezing point (precooling stage), (b) removing the latent heat of crystallization (phase transition stage), and (c) reducing the temperature to the final storage temperature (subcooling stage) [ 48 , 49 , 50 ]. Nucleation is the initial requirement for freezing, and the occurrence of nucleation requires a driving force called supercooling [ 51 ].…”

“…Generally, low supercooling degrees cause large ice crystals to form in intercellular spaces and high supercooling degrees result in the formation of smaller ice crystals [ 52 , 53 ]. During freezing, food structures might be under the influence of ice crystal formations within and outside the cells [ 49 ]. For food and biological materials, the morphology, size, and distribution of ice crystals presents significant effects on their microstructure.…”

“…Fast freezing processes enhance quality and extend the shelf life of food by preventing microbial growth, reducing water activity, and decreasing chemical and enzymatic reactions [ 59 , 60 ] through the formation of the small and uniform intracellular and extracellular ice crystals in all over the tissue [ 45 , 61 ]. Although high freezing rates protect the tissue structure to a better extent than with slow freezing [ 62 ], freezing too quickly leads to mechanical cracking, especially in large products with a high moisture content and low porosity [ 49 , 63 ]. To reduce the freezing duration and control ice nucleation and the formation of countless tiny intracellular ice crystals, new methods such as ultrasound assisted food freezing [ 64 ], supercooling technology [ 63 ], high pressure freezing [ 65 ], magnetic and electromagnetic field-assisted freezing [ 46 , 66 , 67 ] have been introduced; however, these systems still need to be optimized [ 44 , 66 , 68 ].…”