Study On Ferulic Acid And Feruloyl Esterase In Wheats And Malts

Wheat malt is a good raw material for brewing, and the beer is a popular drink in current in the world. Selecting the suitable wheat variety for malting is an effective measure to develop advanced processing of wheat, to enhance the income of peasant, and is helpful to the development of wheat, malting and beer industry. In this research the content of ferulic acid and feruloyl esterase and the activities of feruloyl esterase of 5 wheat cultivars were determined and the characteristics of feruloyl esterase were researched. The main conclusions were as follows:1 Through a single factor experiment and orthogonal experiment, the optimum technological parameters for extraction were achieved as methanol volume fraction 60%, material-liquid ratio 1:20 g/mL, temperature 45 oC, time 60 min, shaking frequency 280±10 r/min, and adding 0.2 g/L Na₂SO₃ as protectant into extraction solvent (P<0.05) .2 The contents of the free and total ferulic acid were determined for 5 varieties of wheats and malts. It was found that the free ferulic acid was ranged between 0.414 mg/g and 0.495 mg/g in wheats, and then, 0.543 mg/g and 0.681 mg/g in malts. After germination,? the contents of the free ferulic acid in all of the wheats were raised?in which the increase of the No.1 (Lu Mai 21) and No.4 (Tai Kong 6) was maximum; for the total ferulic acid, the contents distributed over 1.52¹.72 mg/g in wheats and 1.70².09 mg/g in malts, all of the contents of the total ferulic acid were raised?after germination in which the increase of the No.3 (Yan 24) and No.4 (Tai Kong 6) was maximum.3 Taking ethylferulate as substract, the optimal enzymatic hydrolysis conditions of feruloyl esterase were confirmed as hydrolysis time 100 min, the volume ratio of enzymes and substract 0.75 mL/mL, the pH value of extract 6.2.4 The activity of feruloyl esterase was determined for 5 varieties of wheats and malts, and it was found that all of the activity of the enzyme was raised after germination in which the increase of Yan 2415, Lu Mai 21 and Zheng Mai 004 was maximum.5 The study on the characteristic of feruloyl esterase exhibited that the optimal temperature was 60 oC, and it had a better thermal stability between 30³5 oC, remaining over 80% of enzyme activity after insulation; the optimal pH value was 5.0, and the destruction was relatively weaker, remaining over 80% of enzyme activity after insulation; The activity was inhibited by Cu²⁺, Zn²⁺(2 mmol/L), and strongly activated by EDTA.