Effects of ultrasonic thawing on the physicochemical properties of frozen pork

This study was carried out to investigate the effects of ultrasonic thawing on physicochemical characteristics of frozen pork sirloin. To determine the velocity of an ultrasonic thawing machine, -80°C frozen pork sirloins were thawed using 132, 580, and 1,000 kHz ultrasonic thawing machines, and the physicochemical properties of pork sirloin thawed with 15°C tap water and those using the ultrasonic thawing machines were compared. As a result, thawing speed by ultrasonic thawing was three times faster than that of tap water, but drip weight loss rate is increased by about 5% during ultrasonic thawing compared to that during thawing in tap water. However, biochemical properties, such as pH, volatile basic nitrogen, thiobarbituric acid, and total aerobic bacteria, were not improved by ultrasonic thawing. Hunter values, such as total color change and redness, improved slightly after 580 kHz ultrasonic thawing. The hardness and chewiness of the pork sirloin decreased significantly after 580 kHz ultrasonic thawing; however, springiness was not changed. These results indicate that ultrasonic thawing is faster than thawing in tap water, but the physicochemical characteristics of frozen pork sirloin was not significantly improve by ultrasonic sound.