Studies On Green Food Beer Production

As the fast development of social economy, people are now paying more and more attention to food safety. Beer is a common consumable, the drastic competitions occur every year in china between beer producers. They have to improve beer quality to attract more consumers, so green food beer is a good choice. Agricultural department also issue the"Green Food Beer"standard to guide beer producers. The formaldehyde concentration control was studied in this paper, including none-formaldehyde brewing technique and factors influencing formaldehyde metabolism.Little formaldehyde was observed in brewing raw material, lower than 70μg/L. Some formaldehyde was produced during wort boiling due to oxidation. Yeast metabolism also produces fomaldehyde, factors influencing formaldehyde metabolism including dissolved oxygen concentration, original extract concentration, yeast generation, inoculum size, reduction temperature. After orthogonal test, the optimal brewing technique was 12～13mg/L of oxygen concentration, yeast generation below 3 with a inoculum size of 2×10~7 cell/ml.In this paper the possible mechanism of haze development was observed, different adsorption selectivity to haze active protein of polyphenol was found under different storage condition. To improve beer non-biological stability, the concentration of polymerized polyphenol must be decreased, exorbitant total polyphenol concentration also resulted to worse non-biological stability. Otherwise, oxidation was a important factor influencing haze development.In order to estimate the effectiveness of beer non-biological stabilizer, the adsorption character of PVPP and silica gel was also studied in this paper, HPLC analysis showed that PVPP has a selective adsorption to polyphenol polymers at low PVPP dosage, but the same result was not found at high PVPP dosage, while the concentration of simple polyphenols and monomers sharply decreased. The amino analysis result showed that silica gel had a selective adsorption to haze active protein. The interaction of PVPP and silica gel would decrease their adsorption effectiveness. So PVPP was added during wort boiling, the wort quality was improved by PVPP, wort antioxidating ability was obviously increased together with a thorough protein deposition.The addition technique was observed after adsorption character was studied, 200mg/L of PVPP was added to wort during wort boiling, 150 mg/L of silica gel was added together with beer filtration. The brewing test was operated in 50 ton vessel, beer brewed without adding formaldehyde had a better flavor stability and a same non-biological stability compared to beer adding formaldehyde. The brewing index was also controlled, rudimental formaldehyde concentration was bellow 200μg/L.