Preparation Of High Fructose Syrup From Garlic Dregs By Enzymatic Hydrolysis

Garlic fructan, which include fructose (85%), glucose (14%) and lactose (1%), is the main component of garlic essential oil production byproduct. Fructose and glucose in molecular is about 15:1. Fructoses are linked byβ-2,landβ-2,6. High fructose syrup (HFS) production by hydrolysis of garlic dregs, which not only is a comprehensive utilization of garlic essential oil production byproduct, but also a new way to prepare HFS. In this thesis, HFS was prepared by hydrolyzing garlic dregs either using inulinase from Kluyveromyces marxianus CICC9009 or commercial invertases respectively. The results are as follows:(1) Fermentation parameters for inulinase production by Kluyveromyces marxianus were optimized. The optimal parameters of fermentation was 1% inulin,1.51% yeast extract,0.5% (NH4)2HPO4,0.05% ZnSO4,6.32% inoculum, at 30℃, pH 6.5 with a fermentation time of 72 h. The prepared inulinase were composed of endoinulinase (39.16 U/mL) and exoinulinase (94.57 U/mL).(2) Preliminary purification of inulinase from Kluyveromyces marxianus was conducted. Inulinase was salted out by ammonium sulfate, and at the best range of saturation level 40%～80%. It was found out that the highest garlic dregs hydrosysis rate was 96% which was achieved at pH 4.8,45℃, with a substrate concentration of 9 mg/mL, and an enzyme concentration of 53.95 U/mL, hydrolyzing for 8 h.(3) Two sucrases were used for high fructose syrup production. It was found out that the highest fructose syrup yield was 80% which was achieved at pH 4.8,45℃, substrate concentration 8 mg/mL, and enzyme concentration of 210 U/mL substrate after hydrolyzing for 12 h.(4) The sucrase (sigma) was immobilized by D201 (strongly alkaline macroporous anion exchange resin). It was found out that the best high fructose syrup yield was 85% which was achieved at pH 5.0,45℃, substrate concentration 10%, and 0.4 mL/min velocity substrate after hydrolyzing for continuous 4 d in the Packed bed reactor. The immobilized-invertase were more stalbe to heat and pH. Attenuation quotient of the immobilized invertase kd was 0.0241, and half life period t1/2 was 27 d. (5) By comparing the hydrolysis of garlic dregs using inulinase and invertase, I found the rate of inulinase hydrolysis was up to 96%. Products were mainly fructose in HFCS. Therefore, the garlic residue is a new material for the production of HFCS.