Heat Transfer in the Cooling, Freezing and Post-Freezing of Liquid Food: Modeling and Simulation

Abstract

In pursuit of greater practicality in the food preparation, in recent years there has been a considerable growth of researches in the field of cooling and freezing of food. Therefore, the trade in frozen food has been very promising, allowing a great variety of products to the consumers due to the convenience of transportation, storage and use. Cooling and freezing of products are preservation methods used in the food industry to maintain the sensorial attributes and nutritional properties of these products. In this sense, in order to optimize the process and reduce energy costs, this work presents a transient three-dimensional mathematical modeling to describe the heat transfer inside liquid materials with parallelepiped shape including phase change (liquid-solid) term. The governing equation was solved numerically using the finite volume technique with a fully implicit formulation. As an application, the methodology was used to predict heat transfer during cooling, freezing and post-freezing of the Tahiti lemon pulp. Numerical results of the temperature distribution at different process instants are presented and analyzed, and temperature data at the center of the product throughout time were compared to experimental data reported in the literature and a good agreement was obtained.

Food preservation techniques and nanotechnology for increased shelf life of fruits, vegetables, beverages and spices: a review

“…Cooling and freezing of products have been extensively applied for preservation of leafy vegetables, spices and milk products to maintain the sensorial attributes and nutrition qualities. Extensively used freezing techniques involve air blast, cryogenic, direct contact and immersion freezing, while advanced techniques involve high pressure freezing, ultrasound assisted freezing, electromagnetic disturbance freezing and dehydration freezing (Cheng et al 2017 ; Barbosa de Lima et al 2020 ). Cooling and freezing process mainly relies on the process of heat transfer.…”

“…Although cooling and freezing are effective in their own terms, cooling time, uneven speed of ice crystal formation, storage expenses and specialized environments are concerning issues. In order to understand and overcome these challenges, technological tools like three-dimensional mathematical models and computational fluid dynamics models were evaluated to understand the heat transfer and fluid flow patterns with various food formulations thus showing an approach to minimize the issue (Zhu et al 2019a , b ; Barbosa de Lima et al 2020 ; Brandão et al 2020 ; Stebel et al 2020 ). Table 2 shows a description of the various advanced freezing techniques applied to different foods.…”

Potenciais problemas significadores em aulas investigativas: contribuições da perspectiva histórico-cultural

“…Historicamente, essa preocupação com uma educação focada na solução de problemas foi derivada dos métodos que enfatizavam uma aprendizagem ativa dos alunos e que buscavam desenvolver o pensamento criativo dos mesmos. Assim, o trabalho com "soluções de problemas" surgiu como uma estratégia a ser utilizada pelos professores como forma de tornar o ensino mais atraente e menos expositivo, a fim de possibilitar mudanças qualitativas na atividade mental dos estudantes (FREITAS, 2012;SILVA, NÚNEZ;RAMALHO, 2001;VASCONCELLOS et al 2012;BARBOSA-LIMA;CARVALHO, 2002;GIL et al, 1992; ECHEVERRÍA; POZO, 1998).…”

“…informações e defendeu a ideia de que os alunos deveriam aprender ciências por meio de (BORGES, 2002;BARBOSA-LIMA;CARVALHO, 2002;LABURÚ, 2003;AZEVEDO, 2004;MUNFORD;LIMA, 2007;CARVALHO, 2013;SCARPA;SILVA, 2013;CLEMENT, 2013; GOUW; FRANZOLIN; FEJES, 2013).…”

“…defendem que o objetivo do ensino deve ir além do conteúdo específico, deve propor que os alunos se engajem no desenvolvimento desta disciplina como produção científica. Essa discussão apresenta conexão com a epistemologia da Ciência, com destaque especial para o problema, visto que ele se configura como elemento central da prática científica, pois de acordo comBachelard (1996) "todo conhecimento é resposta a uma questão".Embora os autores que defendem o Ensino por Investigação reconheçam o papel do problema como gênese da construção do conhecimento na Ciência e especialmente no aprendizado escolar(CARVALHO et al, 1998;BARBOSA-LIMA;CARVALHO, 2002;AZEVEDO, 2004;CARVALHO, 2011a; CAPECCHI, 2013;RABONI, 2013), este parece não ser utilizado como ponto de partida na estruturação das SEI. Portanto, eles assumem uma função muito mais de artificio didático-pedagógico, do que de estruturador curricular (SOLINO; GEHLEN, 2014).…”