d-Psicose, an epimer of d-fructose, occurs in very small quantities in nature; however, microbial isomerases that convert d-fructose to d-psicose have been discovered, enabling d-psicose to be industrially mass produced. d-Psicose is a rare sugar that is low in energy (about 10 % of sucrose) and has disease-preventing effects such as suppression of postprandial blood glucose elevation. d-Psicose has been investigated for use in processed foods in North America and Asia, with applied research beginning in the 2 000 s. Early research aimed to improve the gelling ability of food proteins by non-enzymatic glycation of d-psicose utilizing the Maillard reaction. Subsequently, application of the food properties, including physical properties and storage stability, of d-psicose to processed foods as an alternative to conventional sugars such as sucrose has been studied. The use of d-psicose in place of sucrose improved the physical properties and storage stability of processed foods. The mechanism of these effects of d-psicose is attributable to its ability to confer a high water-holding capacity to the processed foods. Furthermore, d-psicose more readily facilitates the Maillard reaction with proteins in foods relative to other reducing sugars, and the resulting reaction products are involved in improving the physical properties of processed foods. This review details the food processing characteristics of d-psicose clarified to date.
