Effects of cryoprotectants (NaCl, sucrose and trehalose) on Nostoc sphaeroides (N. sphaeroides) superchilled at −3.0°C as well as their action mechanisms were studied. Prior to storage, N. sphaeroides were immersed into different concentrations (5% and 10%) of NaCl solutions, sucrose solutions, and trehalose solutions for 2 hr. The texture properties, drip loss and low field nuclear magnetic resonance (NMR)-imaging of N. sphaeroides with different treatments were evaluated. The freezing point, solute absorption, water distribution and microscopic structure were also measured to illustrate the action mechanisms of cryoprotectants. Results suggested that cryoprotectants offered an effective method for keeping the texture properties, lowering drip loss, and maintaining the shape of N. sphaeroides. Among all the cryoprotectants used, 5% NaCl exhibited the best effect. The study of their action mechanisms showed that cryoprotectants were efficient in reducing the freezing point, the proportion of free water and microscopic structure destruction of N. sphaeroides. Practical Applications: Considering the higher water content of N. sphaeroides, it is not suitable to be deeply frozen because the formation of numerous ice crystals can cause severe damages to the tissue. To suppress these undesirable changes in superchilling, cryoprotectants including NaCl, sucrose and trehalose are added to the food products. This research contributes to lay a theoretical foundation for the further study of superchilling storage of N. sphaeroides.

中文翻译：

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低温保护剂对低温（-3.0°C）超冷发菜的影响及其作用机制

研究了冷冻保护剂（NaCl、蔗糖和海藻糖）对 -3.0°C 超冷的 Nostoc sphaeroides (N. sphaeroides) 的影响及其作用机制。在储存之前，将球状球孢菌浸入不同浓度（5% 和 10%）的 NaCl 溶液、蔗糖溶液和海藻糖溶液中 2 小时。评估了不同处理的球状猪笼草的质地特性、滴水损失和低场核磁共振 (NMR) 成像。还测量了冰点、溶质吸收、水分分布和微观结构，以说明冷冻保护剂的作用机制。结果表明，冷冻保护剂提供了一种有效的方法来保持质地特性、降低滴水损失和保持球状猪笼草的形状。在所有使用的冷冻保护剂中，5% NaCl 的效果最好。对其作用机制的研究表明，冷冻保护剂可有效降低球状烟草的凝固点、游离水比例和微观结构破坏。实际应用：考虑到球状猪笼草的含水量较高，不适合深度冷冻，因为大量冰晶的形成会对组织造成严重损害。为了抑制过冷的这些不良变化，食品中添加了包括 NaCl、蔗糖和海藻糖在内的冷冻保护剂。该研究有助于为进一步研究球形猪笼草的超低温贮藏奠定理论基础。N. sphaeroides 的游离水比例和微观结构破坏。实际应用：考虑到球状猪笼草的含水量较高，不适合深度冷冻，因为大量冰晶的形成会对组织造成严重损害。为了抑制过冷的这些不良变化，食品中添加了包括 NaCl、蔗糖和海藻糖在内的冷冻保护剂。该研究有助于为进一步研究球形猪笼草的超低温贮藏奠定理论基础。N. sphaeroides 的游离水比例和微观结构破坏。实际应用：考虑到球状猪笼草的含水量较高，不适合深度冷冻，因为大量冰晶的形成会对组织造成严重损害。为了抑制过冷的这些不良变化，食品中添加了包括 NaCl、蔗糖和海藻糖在内的冷冻保护剂。该研究有助于为进一步研究球形猪笼草的超低温贮藏奠定理论基础。为了抑制过冷的这些不良变化，食品中添加了包括 NaCl、蔗糖和海藻糖在内的冷冻保护剂。该研究有助于为进一步研究球形猪笼草的超低温贮藏奠定理论基础。为了抑制过冷的这些不良变化，食品中添加了包括 NaCl、蔗糖和海藻糖在内的冷冻保护剂。该研究有助于为进一步研究球形猪笼草的超低温贮藏奠定理论基础。