Effect of Novel Quick Freezing Techniques Combined with Different Thawing Processes on Beef Quality

Challenges and processing strategies to produce high quality frozen meat

Freezing is an effective means to extend the shelf-life of meat products. However, freezing and thawing processes lead to physical (e.g., ice crystals formation and freezer burn) and biochemical changes (e.g., protein denaturation and lipid oxidation) in meat resulting in loss of quality. Over the last two decades, several attempts have been made to produce thawed meat with qualities similar to that of fresh meat to no avail. This is due to the fact that no single technique exists to date that can mitigate all the quality challenges caused by freezing and thawing. This is further confounded by the consumer perception of frozen meat as lower quality compared to equivalent fresh-never-frozen meat cuts. Therefore, it remains challenging for the meat industry to produce high quality frozen meat and increase consumer acceptability of frozen products. This review aimed to provide an overview of the applications of novel freezing and thawing technologies that could improve the quality of thawed meat including deep freezing, high pressure, radiofrequency, electro-magnetic resonance, electrostatic field, immersion solution, microwave, ohmic heating, and ultrasound. This review will also discuss the development in processing strategies such as optimising the ageing of meat pre- or post-freezing, and the integration of freezing and thawing in one process/regime to collapse the difference in quality between thawed meat and fresh-never-frozen equivalents.

The impact of quick-freezing methods on the quality, moisture distribution and microstructure of prepared ground pork during storage duration

The aim of present study was to investigate the influences of ultrasound-assisted immersion freezing (UIF), immersion freezing (IF) and air freezing (AF) on the quality, moisture distribution and microstructure properties of the prepared ground pork (PGP) during storage duration (0, 15, 30, 45, 60, 75 and 90 days). UIF treatment significantly reduced the freezing time by 60.32% and 39.02%, respectively, compared to IF and AF (P < 0.05). The experimental results of quality evaluation revealed that the L* and b* values, juice loss, cooking loss, TBARS values and carbonyl contents were decreased in the UIF treated samples, while the a* value, peak temperatures (Tm), enthalpy (ΔH) and sulfhydryl contents were significantly higher than those of IF and AF treated samples (P < 0.05). In addition, low-field nuclear magnetic resonance (LF-NMR) and differential scanning calorimetry (DSC) analysis demonstrated that UIF inhibited the mobility of immobilized water and reduced the loss of immobilized and free water, and then a high water holding capacity (WHC) was achieved. Compared to the IF and AF treatments, the UIF treated PGP samples possessed better microstructure. Therefore, UIF could induce the formation of ice crystals with smaller size and more even distribution during freezing process, which contributed to less damage to the muscle tissue and more satisfied product quality.

Influence of Horse Age, Marinating Substances, and Frozen Storage on Horse Meat Quality

Simple Summary

The age of horses can influence several properties of the obtained raw material. As the age of horses increases, the meat retains less water, and more fat (p < 0.05) and minerals. In general, horse meat from older animals exhibits undesirable stringiness and hardness, due to a large proportion of connective tissue (collagen). Currently, many methods are applied to improve the tenderness of meat. Of these, the most popular is marinating the meat with various substances, which enhances the functional and sensory properties of the meat. Freezing is a widely accepted method for extending the shelf life of meat. Both the technique used for freezing and further storage at negative temperatures have an impact on some of the properties of meat. Most importantly, the pH value, color, and water absorption of meat tend to change with freezing. In addition, the dry matter content and tenderness of meat increase. This study aimed to analyze the impact of horse age, marinating substances, and frozen storage on the quality of horse meat. As horses age, the values of meat cutting force increase (p < 0.05). For example, the cutting force increases by 4.57 N/cm² during the first period of freezer storage, and by 3.28 N/cm² after 3 months of freezer storage (p < 0.05).

Abstract

The present study analyzed the influence of horse age, substances used for marinating, and frozen storage on the quality of horse meat. It was conducted on the samples of the longest thoracic muscle, obtained from 12 carcasses of horses (aged 4–7 and 8–12 years). Among the analyzed samples, a higher fat content (p < 0.05) was found in the meat obtained from the carcasses of older horses. The pH value of the meat samples was influenced by the treatment applied (p < 0.05). Of the substances used for marinating, malic acid caused a decrease in the pH of the meat obtained from young horses (p < 0.05). A similar effect was observed with the addition of phosphates to malic acid-marinated meat. On the other hand, the use of phosphates for marinating resulted in an increase in the pH of the meat obtained from older horses (p < 0.05). The substances used for marinating the horse meat did not significantly affect the reduction in cutting force values. Furthermore, the values of shear force, hardness, stiffness, gumminess, and chewiness of the meat increased with horse age (p < 0.05). An influence on the color parameters a* and b* of the meat was found for the interaction between age, storage period, and the type of treatment (p < 0.05). The use of lactic acid and malic acid for marinating the meat of young horses caused a decrease in the proportion of red color (4.67 and 3.43) and an increase in the proportion of yellow color (3.81 and 1.71), especially after 3 months of freezer storage. All the substances used for marinating (except for phosphates) were associated with higher (p < 0.05) thermal and forced drips of meat from the carcasses of both young and older horses during each storage period, in comparison to the control. The interaction between age and the type of treatment had an influence on the tenderness and juiciness of the horse meat (p < 0.05). In sensory evaluation, it was noted that the interaction between age and the treatment procedure influenced the tenderness and juiciness of the meat samples (p < 0.05). There is still a need for further research to increase knowledge regarding how to improve the quality of horse meat, and ultimately increase the demand from consumers and meat processing plants.

The effects of the novel home freezing system on microstructure, color, antioxidant activity, and microbiological properties of strawberries

In these days people are more interested in frozen foods, especially home freezing fruits and vegetables. In this study, the effects of a new developed quick freezer system for home-type refrigerator on the freezing rates and some quality properties of strawberries were investigated. The freezing cabinet (at -30 °C with 1.2 ms^-1 air) was designed and manufactured by Bosch und Siemens Hausgerate GmbH (Çerkezköy, Turkey) then the strawberrries were frozen in a novel quick freezer and compared with the samples frozen statically at classic home type refrigerator (at -18 °C without any air blown) via the freezing times at three different (bottom, middle and top) position. Microstructure, color, antioxidant content and microbiological quality during storage of 4 months at -25 °C compared. Strawberries reached -15 °C approximately 234 min shorter in the novel system. Freezing rates were determined as 0.32 cm h^-1 for the static freezer and 1.51 cm h^-1 for the quick freezer. Unlike the classic home-type refrigerator, quick freezing process took place in the novel home freezing system. SEM images showed that higher freezing rate in the novel system provides better protection in tissue structure and cell walls. The antioxidant activity of the strawberries frozen in the novel home freezing system was 8.96% higher after the freezing process. Brightness and redness of samples were protected better after quick freezing during storage. Nonetheless, no evident differences were observed in microbiological criteria.

Physicochemical Properties of Pork Neck and Chicken Leg Meat under Various Freezing Temperatures in a Deep Freezer

This study was conducted to investigate the effects of freezing and storage temperature (−18°C, −50°C, and −60°C) on the physicochemical properties of pork neck and chicken leg meat in home-scale deep freezers. Pork neck was cut into a thickness of 3 cm (9×9×3 cm, 150 g), individually packed in air-containing packages, and stored at different temperature (−18°C, −50°C, and −60°C) for 6 months. Chicken leg meats were prepared (10 cm long, weighing 70 g) and packed in the same manner. Frozen samples were thawed at 2°C. Physicochemical properties such as thawing loss, cooking loss, water-holding capacity, color, volatile basic nitrogen (VBN), and thiobarbituric acid reactive substances (TBARS) were evaluated. The samples frozen by deep freezing (−60°C) was favorable with respect to thawing loss, color, and VBN. Samples frozen at −60°C had lower values of thawing loss and VBN than those frozen at −18°C for all storage periods (p<0.05). Color parameters were more similar to those of fresh meat than to those of samples frozen at −18°C for 6 months. The TBARS of all samples were below 0.3 mg malondialdehyde/kg, thereby indicating oxidative stability of lipids. Consequently, deep freezing at −60°C may be acceptable for maintaining the quality of fresh pork neck and chicken leg meat for 6 months without deterioration.

The impact of freezing methods on functional and technological properties of semi-finished rabbit meat products

During storage meat and semi-finished meat products, the decisive factor is the correct implementation of freezing process, because the physical, histological, biochemical, microbiological changes that occur at this time, affect the final quality of product after defrosting procedure. Accordingly, studies of the impact of traditional and shock-freezing methods on functional and technological properties of semi-finished rabbit meat products represent scientific and practical interest. The effect of freezing temperature of natural and minced semi-finished rabbit meat products on the duration of cold treatment process has been studied, and the regression equations of their relationships have been obtained and regression curves have been constructed. It has been established that unlike traditional method, by the type of semi-finished products, the duration of cold treatment by shock-freezing method is 3 - 3.5 times shorter. The optimal freezing parameters have also been selected. It has been shown that the use of shock-freezing method contributes to the reduction of mass losses of semi-finished rabbit meat products, and by the type of semi-finished products, they are 5 - 5.3 lower as compared to traditional method of freezing. The determination of functional properties has revealed that shock-freezing allows for increasing water binding capacity-by 23.2 - 31.9%, water holding capacity-by 20 - 25% and pH by 6.7 - 10.4%. There have been studied microbiological indicators of frozen semi-finished products and their changes during the storage process. It has been established that they meet the safety and hygiene requirements for meat products. The full results obtained indicate the advantage of shock-freezing method as compared to traditional methods, as well as point to the appropriateness of its use when selecting the cold treatment modes for semi-finished rabbit meat products.

Effect of tempering methods on quality changes of pork loin frozen by cryogenic immersion

The quality characteristics of pork loin frozen by cryogenic immersion were examined, such as the drip loss, cooking loss, water holding capacity, moisture content, protein solubility, lipid and protein oxidation, color, and microstructure, and compared after different tempering methods: radio frequency (27.12MHz), water immersion, forced-air convection, and microwave tempering. Forced-air tempering was the most time-consuming process, whereas electromagnetic energy methods (radio frequency and microwave) were the shortest. The tempering rate of radio frequency at 400W was 5 and 94 times greater than that obtained with water immersion and forced-air tempering, respectively. The drip loss, water holding capacity, moisture content, color, and microstructure of pork samples all declined as a result of microwave tempering. By contrast, the least degree of changes in the drip loss, microstructure, and color of the pork loin samples was obtained with radio frequency tempering, suggesting its potential application in providing rapid defrosting without quality deterioration in the frozen meat industry.