Here we have performed a comparison of frozen litchi fruits which have undergone either immersion or air-blast freezing. An analysis of the quality changes of frozen litchi fruit during its refrigerated storage was done for 6e12 months post-freezing. IF was found to be a greatly superior freezing method, with quality similar to fresh litchis, whereas AF led to deterioration of the fruits. The higher freezing rate and the better integrity of microstructure of IF litchis likely explained the higher preservation quality in terms of reduced drip loss, color retention, and texture quality. The freezing procedure must be an integrated and systematic process for optimal quality preservation incorporating a series of treatments
including color-protecting, vacuum packaging, precooling, immersion freezing, frozen storage and quick thawing. Among these treatments, the high freezing rate in IF played the most important role in guaranteeing good quality during frozen storage because of the small size of ice crystals and reduced damage to the fruit microstructure. A constant long-term storage temperature followed by a quick and uniform thawing process ensured the maintenance of these advantages through inhibiting ice crystal growth and recrystallization. These processes were indispensable for the good quality preservation of litchi fruit during storage. IF has clear and demonstrable advantages in enhancing the quality of frozen litchis. Since further studies and optimization efforts will be carried out in the future, immersion freezing technology could be a novel application for long term storage of litchi fruits as well as for all other frozen food with very promising industrial potential.