Application of combined infrared-air circulation system on thawing of beef and its effect on the quality properties

Background and objectives: Thawing food products leads to changes that can influence the quality of the final product. Traditional thawing methods are time-consuming and can negatively affect the quality of the product. In contrast, modern thawing methods such as microwave, high pressure, ohmic, and infrared techniques have been shown to preserve higher nutritional value in the thawed product. While extensive research has been conducted on meat freezing, there is a lack of studies focusing on the optimal conditions for thawing using modern methods and their impact on meat quality. Therefore, the objective of this research is to investigate the effect of using a combined infrared-air circulation system to thaw beef, specifically evaluating its impact on chemical properties such as pH, as well as physical properties including thawing loss, color, and texture of the meat
Materials and methods: First, the beef was cut into rectangular cubes with dimensions of 5x3x3 cm and weighed. Then it was frozen in a freezer at -18℃ and kept there for 5 days. In order to thaw the frozen samples, a combined infrared-air circulation system was used. The thawing parameters included the power of the infrared radiation source (100, 200 and 300 W), air temperature (30 and 40 °C) and air circulation velocity (2.5 and 5 m/s). The effect of these parameters on the thawing time, thawing rate, thawing loss, cooking loss, water holding capacity, pH, color and texture were evaluated.
Results: Regardless of the air velocity, increasing the infrared power increased the thawing rate of beef. This value was raised more by increasing the air temperature and its circulation velocity. The thawing loss of the infrared treatment with 100 W was significantly lower than the 0 W treatment, although increasing the infrared power and the air temperature and its circulation velocity increased the thawing loss of beef (P<0.05). The pH value of thawed samples in different infrared powers at different levels of air temperature and velocity parameters have a significant difference (P<0.05), although the effect of infrared power itself on pH changes is not significant. As the air temperature and velocity increased, the pH value decreased. Applying infrared and increasing its power, as well as air circulation, decreased the expressible moisture of thawed beef and, as a result, increased the water holding capacity and reduced the cooking loss. The use of different levels of infrared power and air temperature did not cause significant changes in the color brightness of the samples and color index a* (P<0.05), but the color index b* of the samples decreased with increasing air temperature. Meanwhile, the amount of this parameter remained almost constant with the change of infrared power levels and air circulation velocity (P<0.05). Increasing infrared power without air circulation decreased the shear force of beef, but by circulating air and increasing its velocity, the shear force generally increased. Although at a higher temperature, with a further increase in the air velocity and as a result of the drying of the meat tissue, the shear force decreased.
Conclusion: The results showed that increasing the infrared power and air velocity both increase the thawing rate and water holding capacity and reduce the cooking loss of beef. No significant difference was observed between the applied treatments on color changes. The increase in air temperature and its circulation velocity decreased the pH. Increasing the infrared power and air temperature decreased the amount of shear force, but it increased with the increase of air circulation velocity.