3种抗冻剂处理对凡纳滨对虾冻融循环期间品质及营养变化影响

为评估蔗糖山梨醇、三聚磷酸钠与卡拉胶寡糖等3种抗冻剂处理对凡纳滨对虾冻融期间的抗冻保水效果，分析其营养及风味变化，将新鲜样品分别在30 g/L的蔗糖山梨醇（Sucrose sorbitol, SS）、30 g/L三聚磷酸钠（Sodium tripolyphosphate, ST）与30 g/L卡拉胶寡糖（Carrageenan oligosaccharides, CO）溶液中浸渍处理2 h，以无菌水浸渍处理2 h为对照组（CK）。样品经聚乙烯（Polyethylene, PE）袋包装后冻藏。期间，实验模拟了凡纳滨对虾流通期间的6次冻融循环，分别以持水力（Water holding capability, WHC）、Ca2+-ATPase活性、核磁成像（Magnetic resonance imaging, MRI）与傅立叶变换红外显微成像(Fourier transform infrared imaging, FT-IRI)为评价指标，同时结合基本营养成分与氨基酸分析，综合评价3种抗冻剂处理对冻融凡纳滨对虾的保水效果及品质变化影响。结果得出，与SS、ST处理相比，CO处理能有效延缓冻融样品的WHC、Ca2+-ATPase活性与基本营养成分下降；由氨基酸分析得出，冻融会使样品中的游离氨基酸含量发生变化，卡拉胶寡糖处理组样品冻融期间的鲜甜味氨基酸、必需氨基酸与氨基酸总量均保持在较高水平；MRI与FT-IRI分析可直观反映冻融凡纳滨对虾的蛋白含量变化与水分迁移状况。可见，卡拉胶寡糖处理对冻融凡纳滨对虾的蛋白质、脂肪与水分的保护作用效果明显，其能在发挥良好抗冻保水效果的同时，较好延缓凡纳滨对虾冻融期间的营养成分降低与品质劣变。

Effects of three antifreeze agents on quality and nutrition of Pacific white shrimp (Litopenaeus vannamei) during freezing and thawing cycles

The aim of this work was to investigate three kinds of different antifreeze agents on quality and nutrition of Litopenaeus vannamei with freezing and thawing (F-T) cycles. Fresh samples were immersed in 30 g/L sucrose sorbitol (SS), 30 g/L sodium tripolyphosphate (ST) and 30 g/L carrageenan oligosaccharides (CO) solutions for 2 h, respectively, and samples immersed in sterile water for 2 h as the control group (CK). Treated samples were packed in PE bags with frozen storage, and 6 cycles of the repeated freezing and thawing were simulated. The anti-freezing effects of different antifreeze agents were evaluated by water holding capability (WHC), Ca2+-ATPase activity, magnetic resonance imaging (MRI) and fourier transform infrared imaging (FT-IRI). The nutritional value changes of pacific white shrimp with F-T cycles were analyzed by the contents of basic nutrional ingredient and amino acids. The results showed that compared with SS and ST samples, the treatment of carrageenan oligosaccharides could effectively inhibit the decrease of WHC, Ca2 +-ATPase activities and basic nutrional ingredient of freeze-thaw samples; According to amino acid analysis, the content of umami amino acids, essential amino acids and total amino acids in CO treated samples were all kept at a high level during F-T periods; MRI and FT-IRI could reflect the changes of protein content and water migration in shrimp directly. In conclusion, The protective effects of carrageenan oligosaccharides on protein, lipid and water of shrimp were significant. It could not only play an important role in water retention and cryoprotective effects, but also keep the better quality and nutrition of Litopenaeus vannamei.