解冻方式对南极磷虾加工品质的影响

为探究解冻工艺对南极磷虾加工品质的影响，对静水解冻、自然空气解冻和低温空气解冻3种方式的耗时进行了测量，并研究了南极磷虾经不同方式解冻后的感官特征，同时对非蛋白氮（non-protein nitrogen，NPN）、总挥发性盐基氮（total volatile basic nitrogen，TVB-N）、硫代巴比妥酸反应物（thiobarbituric acid reactive substances，TBARS）、脂肪酸组成等与品质相关的生化指标进行了测定。结果表明，采用静水解冻、自然空气解冻、低温空气解冻3种方式将中心温度为-18℃的南极磷虾冻块解冻完全的耗时分别为51、220和826 min；感官评分依次为静水解冻>自然空气解冻>低温空气解冻；3种解冻方式对应的NPN值有极显著差异（P<0.01），依次为低温空气解冻>自然空气解冻>静水解冻；低温空气方式解冻的南极磷虾TVB-N值显著高于另2种方式（P<0.01），而静水方式和自然空气方式之间TVB-N无显著差异（P>0.05）；3种解冻方式的TBARS值同样差异显著（P<0.01），依次为静水解冻>自然空气解冻>低温空气解冻；南极磷虾脂肪酸组成中多不饱和脂肪酸比例较高，达到30%以上，低温空气解冻对多不饱和脂肪酸具有一定的保护作用。实际生产中，南极磷虾如用作一般食品加工适宜采用静水解冻的方式，而作为鱼粉加工适宜采用静水或自然空气解冻的方式，如提取虾油则适宜采用低温空气解冻的方式。研究结果为南极磷虾资源的高效利用提供参考。

Effect of thawing methods on processing quality of Antarctic krill

Abstract: Antarctic krill (Euphausia superba) is widely distributed in Antarctic waters. The resource of Antarctic krill is rich, whose fishable amount is up to 100 million tons each year. In China, considerable amount of Antarctic krill is frozen and stored in boats before transported to the land for processing. Therefore, thawing is indispensable in Antarctic krill industry. The thawing way has great effect on the quality of fishery materials. In order to explore how thawing process influenced the quality of Antarctic krill as raw material, 3 ways including natural air thawing, static water thawing and low-temperature air thawing were designed in this study. The consumption of time, sensory evaluation and biochemical indices such as non-protein nitrogen (NPN), total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substance (TBARS) were determined for each kind of thawing method. The results showed that the thawing time taken by natural air way, static water way and low-temperature air way was 220, 51 and 826 min respectively. The sensory score of Antarctic krill with static water thawing was the highest, followed by natural air way and low-temperature air way. The NPN values of Antarctic krill thawed by the 3 ways were 6.89, 8.55 and 12.13 mg/g respectively for static water thawing, natural air thawing and low-temperature air thawing, with the highest value of low-temperature air way, followed by natural air way and static water way in sequence. The TVB-N values of Antarctic krill thawed by the 3 ways were 9.60, 10.33 and 22.47 mg/100 g, respectively. The TVB-N value of low-temperature air way was significantly higher than the other 2 ways, but those of the static water way and natural air way had no significant difference (P>0.05). The TBARS values of Antarctic krill thawed by the 3 ways were 6.77, 4.78 and 2.17 mg/kg, respectively. The differences were significant (P<0.01), with the highest value of static water way, followed by natural air way and low-temperature air way. The proportion of polyunsaturated fatty acids of total fat from Antarctic krill was more than 30%. Low-temperature air thawing had a certain effect on the protection of polyunsaturated fatty acids. In conclusion, in the process of production, choosing the way to thaw Antarctic krill material should fully consider the type of products. The way of static water thawing is suitable for general food processing. The ways of static water thawing and natural air thawing are suitable for fishmeal production. The way of low-temperature air thawing is suitable for shrimp oil extraction.