Enhancing physical and chemical quality attributes of frozen meat and meat products: Mechanisms, techniques and applications

Background: Freezing is one of the most common methods for preserving meat and meat products. Ice crystals are a key factor in the quality of frozen meat and meat products. Common freezing methods used in the food industry such as air-blast freezing and liquid immersion freezing could form large and irregular ice crystals in the extracellular region of the frozen meat and meat products and cause tissue damages, leading to quality and nutrient losses upon thawing. Therefore, it is important to enhance the quality of frozen meat and meat products by controlling the formation and distribution of ice crystals during freezing. Scope and approach: This review presents the key mechanisms in enhancing the physical and chemical quality attributes of frozen meat and meat products and the techniques available for realizing these enhancements. The mechanisms discussed include acceleration of freezing rates, formation of small and evenly distributed ice crystals and generation of intracellular ice crystals. The effects of these mechanisms on enhancing microstructure, moisture, texture feature, and colour, and pH values, protein, and lipid are analyzed in detail. In addition, their effects on microbiological safety are also discussed. Key findings and conclusions: The improvements in the quality of frozen meats can be achieved through the control of the formation and distribution of ice crystals in different approaches. Among the techniques available for realizing these improvements, high-pressure freezing, ultrasound-assisted immersion freezing, and oscillating magnetic field-assisted freezing can form small and intracellular ice crystals mainly by accelerating the freezing rate, while static electric field-assisted freezing, radiofrequency assisted freezing, and microwave-assisted freezing have the ability to form small ice crystals by controlling the motion of water molecules in electric or magnetic fields. Furthermore, anti-freezing proteins can combine with water molecules to inhibit the growth of ice crystals, thereby forming small ice crystals. However, many challenges remain in the research and exploitation of these novel technologies, and further studies can focus on establishing models for describing freezing processes assisted by the above novel freezing technologies, developing techniques for the proper control of ice crystal nucleation, growth, and distribution, translating laboratory results of the above novel freezing techniques into industrial applications.