Effects of Different Freezing and Thawing Processes on Chicken Quality
YU Bing1, SUN Jingxin1,*, YU Linhong1, LIU Gongming1, HUANG Ming2, XU Xinglian2
1. College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China;
2. College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
Abstract：The objective of this work was to elucidate the effects of two different freezing methods, ordinary freezing at −18 ℃ (freezing 1) and liquid-nitrogen quick freezing (freezing 2), and two different thawing methods, natural thawing at 4 ℃ (thawing 1) and thawing at fluctuating low temperatures (2 ℃ first and then 6 ℃ and 2 ℃ again) and a high humidity higher than 90% (thawing 2), on chicken quality. Four freezing-thawing treatments including 1 + 1, 1 + 2, 2 + 1, and 2 + 2 were designed. Chicken samples from four treatment groups were measured for water retention properties (juice loss, dripping loss, high-pressure water loss, and cooking loss) and tenderness and subjected to protein analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that the weight loss of quick frozen chicken was reduced by 1.07% compared with that of ordinary frozen sample. The best water retention properties were obtained by using freezing 2 + thawing 2, and the resulting thawing loss, dripping loss, high-pressure loss and cooking loss were 0.22%, 0.54%, 44.53%, and 11.93% (P < 0.05), respectively. Degradation of sarcoplasmic proteins was observed to different degrees in all treatment groups, which was minimized by freezing 2 + thawing 2. Moreover, this treatment was the most effective for reducing deterioration of chicken quality, increasing water holding properties and decreasing weight loss during freezing and thawing.
