A review of the use of scraped surface heat exchangers to crystallize fats and fat-based products

Scraped surface heat exchangers (SSHE) are very important in many industries including chemical, cosmetic, pharmaceutical, and food. Some of the applications of SSHE in the food industry are to control the crystallization process in fats and frozen desserts, among other applications. This can be achieved because of the scraping action of the fixed blades that continuously rotate within the cooling surface removing the crystallized product from the surface, improving heat transfer, preventing crystal build-up on the wall, and accelerating the crystallization process. There are many process parameters that can be controlled in the SSHE to control and tailor the fat crystallization process, and many fat-based products can benefit from this machine, such as shortenings, spreads, and chocolates. Moreover, SSHE have recently been coupled to other processing devices such as high intensity ultrasound (HIU), high pressure homogenizers, and others to improve the crystallization process even further. This review focuses on the importance of SSHE in fat and fat-based products and discusses the importance of the parameters of the SSHE in the crystallization process, as well as how they affect the physical properties of different fat sources and spreads.