Ice Morphology: Fundamentals and Technological Applications in Foods

Abstract

Freezing is the process of ice crystallization from supercooled water. Ice crystal morphology plays an important role in the textural and physical properties of frozen and frozen-thawed foods and in processes such as freeze drying, freeze concentration, and freeze texturization. Size and location of ice crystals are key in the quality of thawed tissue products. In ice cream, smaller ice crystals are preferred because large crystals results in an icy texture. In freeze drying, ice morphology influences the rate of sublimation and several morphological characteristics of the freeze-dried matrix as well as the biological activity of components (e.g., in pharmaceuticals). In freeze concentration, ice morphology influences the efficiency of separation of ice crystals from the concentrated solution. The cooling rate has been the most common variable controlling ice morphology in frozen and partly frozen systems. However, several new approaches show promise in controlling nucleation (consequently, ice morphology), among them are the use of ice nucleation agents, antifreeze proteins, ultrasound, and high pressure. This paper summarizes the fundamentals of freezing, methods of observation and measurement of ice morphology, and the role of ice morphology in technological applications.

Changes of proteins during superchilled storage of Atlantic salmon muscle (Salmo salar)

“…The degree of protein denaturation is influenced by many factors such as treatments before partial freezing, state of rigor at the time of partial freezing, partial freezing rate, ultimate partial freezing temperature, storage temperature, storage time, fluctuation of storage temperature, and thawing methods (Benjakul and Visessanguan 2010;Blond and Meste 2004;Chevalier et al 2001;Hagiwara et al 2002;Jiang and Lee 1985;Kiani and sun 2011;Martino et al 1998;Mittal and Griffiths 2005;Petzold and Aguilera 2009).…”

Long-term frozen storage of wheat bread and dough – Effect of time, temperature and fibre on sensory quality, microstructure and state of water

“…At these temperatures recrystallisation of ice crystals occurs in which ice crystals 294 change in number, size and shape (Petzold and Aguilera, 2009). This results in bigger ice crystals, 295 which leads to destruction of the structure and possibly also of the yeast cells.…”

An Overview on Magnetic Field and Electric Field Interactions with Ice Crystallisation; Application in the Case of Frozen Food

“…The immobilisation of free water inhibits the microbial growth, and slows down enzymatic and chemical degradation reactions resulting in slower rates of deterioration of food products [1,2]. The size of ice crystal is pivotal to textural and physical properties of frozen and frozen-thawed foods and to processes such as lyophilisation, and freeze concentration [3]. In food commodities with cellular structure (e.g., fruits, vegetables and meat, etc.…”

“…In freeze concentration, larger size ice crystals of uniform size are desired as it will facilitate the separation of ice crystals from the concentrated mother solutions. Moreover, they are characterised by low surface area per unit of mass, and therefore, the loss of entrained juice concentrate can be minimized [3,6,7].…”

“…On the contrary, higher cooling rates would yield smaller size of ice crystals. In the recent years, several new approaches have been proposed for controlling the ice nucleation; among them are the uses of high-pressure shift [8], ultrasound waves [9], electric fields [10][11][12], magnetic fields [13], electromagnetic waves [14], ice nucleation agents [3], antifreeze proteins [15], ice nucleating bacteria [15] and others. This review article summarizes the fundamentals of freezing under magnetic, electric and electromagnetic fields, and their applicability in the food industry.…”