Institute of Marine Research, Bergen, Norway.
J Food Sci. 2024 Aug;89(8):4660-4670. doi: 10.1111/1750-3841.17216. Epub 2024 Jul 25.
We hypothesized that removing water from fish muscle homogenate by freeze-drying might be a cost-effective way to stabilize nutrients and allow higher temperatures for long-term frozen storage prior to analytical measurements. To test our hypothesis, fish muscle fillets from lipid-rich farmed Atlantic salmon (n = 5) and lean wild-caught European plaice (n = 5) were homogenized and fresh-frozen at -20 and -80°C. A subset of these samples was freeze-dried prior to further frozen storage at the respective temperatures. Using validated methods, vitamins, amino acids, and fatty acids were measured after a short time of storage (starting point) and up to 1 year (endpoint), with intermediate analytical checkpoints of 1, 3, and 6 months. Trends in the degradation of certain nutrients during the different frozen storage conditions are discussed. In general, by freeze-drying fish homogenate samples prior to frozen storage at -20°C for up to 1 year, amino acids, vitamins, and fatty acids were stabilized in both salmon and plaice when compared to wet-frozen storage of the same samples, and storage at -80°C did not improve preservation of the freeze-dried samples. For wet-frozen samples, -80°C would be recommended for 1-year storage of fillet homogenate samples, even though several nutrients preserved well at -20°C. PRACTICAL APPLICATION: We present individual nutrient stability profiles in muscle homogenates from fatty fish (salmon) and lean fish (plaice) during different frozen storage conditions over time. Based on these data, freeze-drying followed by frozen storage at -20°C for at least 1 year could be applied prior to analyses of amino acids, fat-soluble vitamins, water-soluble vitamins, and fatty acids. Of note is that freeze-drying followed by frozen storage before analysis led to slightly increased measurements of several fatty acids in plaice samples, possibly attributable to an increase in dry weight or an enhancement in extraction efficiency through freeze-drying.
我们假设通过冷冻干燥去除鱼肉匀浆中的水分可能是一种经济有效的方法，可以稳定营养物质，并允许在分析测量之前在更高的温度下进行长期冷冻储存。为了验证我们的假设，从富含脂肪的养殖大西洋三文鱼（n=5）和瘦的野生欧鲽（n=5）的鱼肉片中提取鱼肌肉匀浆，分别在-20°C 和-80°C 下新鲜冷冻。这些样品的一部分在进一步在相应温度下冷冻储存之前进行冷冻干燥。使用经过验证的方法，在短时间的储存（起始点）和长达 1 年（终点）后测量维生素、氨基酸和脂肪酸，中间分析时间点为 1、3 和 6 个月。讨论了在不同冷冻储存条件下某些营养素降解的趋势。一般来说，通过在-20°C 下冷冻干燥鱼匀浆样品长达 1 年，与相同样品的湿冷冻储存相比，三文鱼和欧鲽中的氨基酸、维生素和脂肪酸得到了稳定，而-80°C 的储存并没有改善干燥样品的保存效果。对于湿冷冻样品，即使在-20°C 下也可以推荐将鱼片匀浆样品储存 1 年，尽管有几种营养素在-20°C 下保存良好。实际应用：我们展示了在不同冷冻储存条件下，高脂肪鱼类（三文鱼）和瘦鱼（欧鲽）的肌肉匀浆中单个营养素的稳定性随时间的变化情况。基于这些数据，在分析前，可以先进行冷冻干燥，然后在-20°C 下冷冻储存至少 1 年，以分析氨基酸、脂溶性维生素、水溶性维生素和脂肪酸。需要注意的是，在分析前进行冷冻干燥和冷冻储存会导致欧鲽样本中几种脂肪酸的测量值略有增加，这可能归因于干重的增加或冷冻干燥提高了提取效率。
