A kind of dte-immobilized nano-microspheres and preparation method thereof and method for producing d-psicose based thereon

Abstract

The present invention discloses a DTE immobilized nano microsphere and a preparation method thereof, and a method for producing D-psicose based on the DTE immobilized nano microsphere. Two geneticallyengineered bacteria are constructed in the method for one-step synthesis of the DTE immobilized nano microsphere. Firstly, a D-tagatose-3-epimerase gene (dte) is fused to a 5' end of a PHA synthetasegene (phaC) through a fragment of linker by a gene fusion method to obtain a dte-linker-phaC recombination gene fragment, the gene fragment is respectively transformed into food-grade expression hosts of L.lactis NZ9000 and non-endotoxin-contaminated ClearColi for inducible expression, and a PDE nano microsphere with DTE on surface can be synthesized in recombinant L. lactis or recombinant ClearColi cells, so that the DTE is effectively bonded to the surface of the nano microsphere, forming the immobilized DTE and achieving DTE production and immobilization in one step.

Description

technical field [0001] The invention belongs to the field of food technology, and relates to a DTE-immobilized nanometer microsphere, a preparation method thereof and a method for producing D-psicose based on the same. Background technique [0002] D-psicose is a rare sugar that rarely exists in nature. It belongs to hexose and ketose in classification, and is the epimer corresponding to the C3 position of D-fructose. The sweetness of D-psicose is equivalent to 70% of sucrose, and the energy is only 0.3% of sucrose, which belongs to low-calorie sugar. At the same time, the mouthfeel of D-psicose is clean and sweet, almost comparable to other high-calorie sugar tastes, and has similar functional attributes to sucrose (volume function, gelling property, Maillard reaction characteristics, etc.), so it can A complete substitute for sucrose added to food or beverages. In addition, studies have shown that D-psicose also has physiological functions such as regulating blood sugar,...

AI Technical Summary

Problems solved by technology

[0005] However, free D-tagatose-3-epimerase is extremely sensitive to ambient temperature and acid-base conditions, and is easily inactivated; at the same time, the purification steps of free enzyme are complicated and costly; and after the catalytic reaction is completed, the enzyme Difficult to separate from substrates and products, low reuse rate, etc.

These problems have greatly limited the industrialization process of D-psicose

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