Application of Ice Nucleation Proteins to Improve Process Efficiency of Freezing Technologies with Altered Ice Morphology

摘要

This research aimed at applying ice nucleation proteins (INPs) in freezing technologies to improve the efficiency of both freeze concentration and freeze drying processes, with further understanding of the related mechanism of ice morphology using a novel imaging technique (X-ray Computed Tomography).;The application of INPs to freeze concentration process showed significant improvement of process efficiency in a desalination model. With the addition of INPs, an estimation of approximately 50% of the energy cost could be saved to obtain fresh drinking water (<500 ppm). Moreover, the related mechanism of ice morphology was investigated by optical microscope and three dimensional X-ray computed tomography. Their use indicated that INPs promoted the development of a lamellar structured ice matrix with larger hydraulic diameters, which facilitated brine drainage and contained less brine entrapment as compared to control samples. These results suggested great potential for applying INPs to develop an energy-saving freeze concentration method via the alteration of ice morphology.;Our results also showed that INPs could significantly improve freeze drying process efficiency with increased primary drying rate in different food systems. Those improvements further led to reduced total drying time, which suggested an estimated total energy saving of 28.5% with INPs. Our ice morphology results indicated the ability of INPs to alter ice morphology with lamellar ice structure and larger crystal size, which were very likely to facilitate the water vapor flow and improve the sublimation rate. These results revealed great potential of using INPs to improve the efficiency of freeze drying process for a wide range of food and other applications.;Thus, our study reveals the great potential of applying INPs to improve process efficiency of freezing technologies including freeze concentration and freeze drying processes, which can lead to wide applications of INPs to produce food products with higher quality at lower cost. Our study also provides new insights into the three dimensional internal structures of frozen matrices and their relationship with process efficiency, which emphasizes the importance of controlling freezing process and the related ice morphology. Our data of ice morphology change is the first study available in the literature to reveal that INPs could not only affect the nucleation temperature but also significantly change the macroscopic ice structure. This finding of INPs altering ice morphology can have significant impact on basic scientific research and practical applications in food, nutraceutical and pharmaceutical industries.