为探究荔枝的冻融特性，确定其适宜的冻融方式，该研究通过液氮喷雾速冻（-40 ℃/-60 ℃/-80 ℃/-100 ℃）和梯度解冻（-20 ℃/0 ℃/5 ℃/4 ℃/25 ℃）对荔枝冻融特性和品质的影响，并以传统冰柜冻结、浸渍冷冻、室温解冻为对比。结果表明：在-20~-100℃范围内，温度越低，穿过最大冰晶生成带时间越短，对冻结荔枝的保护效果越好；-100 ℃液氮喷雾速冻联合“-20 ℃~-5 ℃~4 ℃~25 ℃”组梯度解冻能够保持新鲜荔枝营养成分和生物活性物质（多酚、可溶性糖、Vc含量分别为3.92 mg/g、150.69 mg/g、2.15 mg/g）85.00%以上，其水分流失仅为5.05%，硬度保留率为57.00%；细胞结构完整性较好，抑制了液泡中的自由水向细胞间和细胞壁的流动，最大程度维持了组织内水分的原有分布。综上，液氮喷雾速冻联合梯度解冻是荔枝适宜的冻融方式，能够较好地维持其品质效果，研究结果可为荔枝的工业贮存与加工提供技术支撑。

In order to explore the freeze-thaw characteristics of litchi and determine its suitable freeze-thaw method, the effects of spray liquid nitrogen quick freezing (-40 ℃/-60 ℃/-80 ℃/-100 ℃) and gradient thawing (-20 ℃/0 ℃/5 ℃/4 ℃/25 ℃) on the freeze-thaw characteristics and quality of litchi were investigated. The obtained results were compared with those of conventional freezer freezing, immersion freezing and ambient temperature thawing. The results show that in the range of -20 ℃~-100 ℃, the lower the temperature, the shorter the time required to pass through the zone of maximum ice crystal formation, and the better the protective effect on frozen litchi. The combination of spray liquid nitrogen quick freezing at -100 ℃ and a gradient thawing process (-20 ℃~-5 ℃~4 ℃~25 ℃) preserved over 85.00% of nutrients and bioactive substances of fresh litchi (polyphenol content, soluble sugar content, Vc content were 3.92 mg/g, 150.69 mg/g, 2.15 mg/g, respectively). This combined treatment caused only 5.05% of water loss and 57.00% of hardness retention rate, and maintained quite well the integrity of cell structures, which suppressed the flow of free water from the vacuoles towards the intercellular spaces between cells and in the cell walls. In summary, spray liquid nitrogen quick freezing combined with gradient thawing is a suitable freeze-thaw method for litchi, which can maintain its quality. The results of this study provide valuable support for the industrial storage and processing of litchi.

广东省重点领域研发计划项目（2020B020225003）；广东省基础与应用基础研究基金项目（2019A1515110559）；广东省农业科学院“优秀博士”人才项目（R2020YJ-YB2001）；广东省现代农业产业共性关键技术研发创新团队建设项目（2021KJ117）；广东省农业科学院青年导师项目（R2020QD-031）