production of high fructose syrup and cocova buffer substitute

production of high fructose syrup and cocova buffer substitute

In recent years, with the rapid increase of sucrose price, the application of fructose has been increasing steadily due to its high sweetness and refreshing taste. Commercial fructose is a product of corn starch. Its preparation process is as follows: firstly, corn starch is hydrolyzed into glucose, and then glucose iso-formed into fructose by fructose isomerase. The content of fructose in the product is about 42%. On this basis, the removal of glucose by multi-step chromatography can increase the purity of fructose to 55% or 90%, known as high fructose syrup (HFCS). A promising method for the preparation of high fructose products is the hydrolysis of plants rich in fructan to produce high fructose. The main purpose of this paper is to study the enzymatic properties of commercial fructozyme of novozymes, and to prepare high fructose products by hydrolyzing inulin with this enzyme. Fructose enzyme optimal pH and temperature were 4.5 and 60 ° C. Studies on the pH stability of the enzyme showed that the enzyme could be stabilized for more than 12 hours at room temperature in the range of pH 4-6. Fructose enzyme in 60 ° C stable 6 h, no obvious enzyme activity decreased. In addition, fructozyme is one of the inulinases in heat resistance, and only 20% of the enzyme activity was lost after 12 hours of heating. These characteristics of fructozyme are conducive to large-scale production of pure fructose, because higher temperature of enzyme reaction is conducive to the inhibition of microbial growth, and can improve the concentration of inulin substrate. In addition, a lower optimum pH prevents the formation of color and undesirable chemical byproducts. The influence of the oscillation rate on the enzyme reaction was studied, and the optimal oscillation rate was 150 RPM. For practical operation, the oscillation rate can be selected from 150 to 200 RPM. The results show that the type of buffer has great influence on the activity of fructozyme, and acetic acid buffer is the best buffer for fructozyme. When the concentration of acetic acid buffer was lower than 100 mM, it had no effect on the enzyme activity; when it was higher than 100 mM, it had a greater effect on the enzyme activity, and the complete inhibition appeared at 500 mM. Chemical and metal ions on enzyme activity research shows that the influence of Ag ~ +, Hg ~ + and Cu ~ (2 +), Mg ~ (2 +) and Fe ~ (3 +) which has strong inhibition of enzymatic activity, with recent ~ (2 +) and Fe ~ (2 +), Na ~ + and Pb ~ (2 +), Li ~ +, EDTA, 2 - mercaptoethanol for some enzymatic activity, and Ca ~ (2 +), Ba ~ (2 +), K ~ +, Al ~ (3 +) and Mn ~ (2 +) and Co ~ (2 +) have the effect that improve the enzyme activity. HPGFC showed that the molecular weight of inulin was 940 g,DP was between 3 and 4, and that of chicory inulin was 2029g,DP was between 9 and 10, suggesting that inulin and chicory inulin were oligosaccharides rather than polysaccharides. The substrate specificity of fructozyme showed that it was active against inulin, sucrose and raffinose, which indicated that it contained certain activity of exogenous inulinase (-d-fructosan fructose hydrolase, EC 3.2.1.80), and exogenous enzyme cut fructose from the non-reducing end of inulin. In addition, the S/I of fructozyme is 1.79(I/S is 0.56), so this enzyme is not a invertase but inulinase. The substrate affinity and kinetic constants of fructozyme were further investigated. The Km and Vmax of sucrose hydrolysis were 0.34mm and 1.65mm l-1 min-1, respectively, and the Km and Vmax of inulin substrate were 0.16mm and 1.32mm l-1 min-1, respectively.