Trang 2 Sinh viên thực hiện MSSVNguyễn Thị Hân20174623Vũ Thị Hằng20174632Vương Thị Hạnh20174643 Trang 4 Beer is a long-standing drink with a long tradition, low alcohol content, delicio
Ứng dụng enzyme vào trình lên men bia Sinh viên thực Nguyễn Thị Hân Vũ Thị Hằng Vương Thị Hạnh Nguyễn Thị Hồng MSSV 20174623 20174632 20174643 20174728 Main content Beer Enzyme in fermentation process Beer Beer is a long-standing drink with a long tradition, low alcohol content, delicious, nutritious taste, high nutritional value and special enzyme system for the digestive system Beer is produced by fermentation of suspended sugars in a liquid medium and is not distilled after fermentation Brewing Process Through all the steps that were mentioned above in the brewing flow chart, enzymes are key factors in maintains and improving those steps Below each enzyme will be mentioned and their role in brewing will be discussed Enzyme in fermentation process Fungal α-amylaseamylase 2.1 α-amylaseacetolactate decarboxylase (ALDC) 2.2 2.3 Protease 2.1 Fungal α-amylaseamylase Amylases are a group of hydrolases which can specifically cleave glycosidic bonds in starch Glucoamylase (exo-1,4-α-d-glucan glucanohydrolase, E.C 3.2.1.3) α- amylases (endo-1,4-α-d-glucan glucohydrolase, E.C 3.2.1.1) Amylase has been derived from several fungi, yeasts, bacteria and actinomycetes Fungal sources are confined to terrestrial isolates, mostly to Aspergillus and Penicillium Fungal α-Amylase is one kind of food grade α-amylase It is made from Aspergillus oryzal var through fermentation and extraction method It is available as a liquid or as a powder formulation Structural and functional characteristics of α-amylaseamylase THE MAJOR ADVANTAGE The major advantage of using microorganisms for the production of amylases is the economical bulk production capacity and the fact that microbes are easy to manipulate to obtain enzymes of desired characteristics Physicochemical properties: Storage conditions: •Ph optima: 5,0 •The enzyme is supplied as an ammonium sulphate suspension in 0.02% sodium azide and should be stored at 4°C •Ph stability: 4,5 – 8,0 •Temperature optima: 52 – 62oc •Temperature stability: 60 – 65oc •They enzyme is completely deactivated above 70°C APPLICATIONS Amylases are extensively employed in processed-food industry: • • • • • Baking Brewing Preparation of digestive aids Production of cakes Fruit juices and starch syrups… 2.2 α-amylaseacetolactate decarboxylase (ALDC) ALDC is produced from a submerged culture of Bacillus subtilis ALDC caused the direct decarboxylation of alpha acetolac-tate to acetoin, thus avoiding the production of Diacetyl Benefits -Reduces Diacetyl production -Significantly reduces maturation times -More efficient vessel utilisation -Improves beer quality -Application and Rates of Use 2.3 Protease Proteases supplementation to high gravity worts enhances fermentation performance of brewer's yeast Proteases supplementation improved wort fermentability of high gravity brewing Proteases supplementation increased the formation of ethanol and flavor volatiles Proteases supplementation had little impact on beer foam stability Neutrase It is a bacterial protease producedby a selected strain of Bacillus amyloliquefaciens withoptimum activity at pH 5.5–5.7 and 45–55 ◦C Flavorzyme It is a fungal protease/amino peptidase mixture produced by a selected strain of Aspergillus oryzae with optimal activity at pH 5.0–7.0 and 50 ◦C Protamex It is a Bacillus protease complex developed for the hydrolysis of food proteins with optimal activity at pH 5.5–7.5 and 35–60 ◦C Cell suspension during fermentation At the end of the corresponding gravity fermentations, wort supplemented with Flavorzyme exhibited the highest number of suspension yeast, with the values of 6.86 g/L (20 ◦P) and 7.07 g/L (24 ◦P), respectively Followed by the Protamex and Neutrase supplementation, 5.39 g/L (20 ◦P) and 6.33 g/L (24 ◦P), 2.55 g/L (20 ◦P) and 5.02 g/L (24 ◦P), respectively Wort fermentability In high gravity worts (20 ◦P),the highest wort fermentability, 85% was achieved for the fermentations with Flavorzyme supplementation, followed by the fermentations with Protamex (83%) and Neutrase (79%) supplementation Ethanol yield The ethanol yield is based on the quantity of consumed sugars (glucose, maltose and maltotriose) in fermented wort Proteases supplementation significantly increased the ethanol production atthe end offermentations (p < 0.05) in 20 ◦P fermented worts, the highest ethanol yield was observed for the fermentations with Flavorzyme supplementation (10.65%) due to its highest wortfermentability, followed by the fermentations with Protamex and Neutrase supplementation, with the values of 10.12% and 9.80%, respectively Beer foam stability Beer foam is an important quality parameter for customers Good foam formation and stability gives an impression of a freshly brewed and welltasting beer It was found that proteases supplementation had little impact on foam stability As with the control beers, beers fermented by adding Neutrase exhibited the best foam stability Flavorzyme and Protamex supplementations made the beer foam stability slightly reduce due to their strong ability of protein hydrolysis