Yeast in Food Fermentation

1. Yeast in Food Fermentation โดย ธนัท อมาตยกุล

2. Saccharomyces In alcoholic fermentation, pyruvate is first decarboxylated (pyruvate decarboxylase) to acetaldehyde that then serves as electron acceptor, giving rise to ethanol (Alcohol dehydrogenase). Glycolysis = produce 4 and use 2 = 2 ATP / NADH After glycolysis 1. alcoholic fermentation, 2. respiration, 3. glyceropyruvic fermentation FSN 311 Food Processing

3. 1 Glucose  2 ethanol + 2 CO2 • ~ 50% conversion FSN 311 Food Processing

4. Regulation of sugar utilizing metabolic pathways • Low concentration of sugar: air enhance yeast cell proliferation (biomass) more than producing ethanol: respiration (Pasteur’s effect)‏ • High concentration of sugar: leading to fermentation > 9 g/L (sugar) air or no air (Crabtree’s effect)‏ FSN 311 Food Processing

5. Wines ENOLOGY vin Enology = Winemaking British version of the word is Oenology FSN 311 Food Processing

6. What is wine? Water ~ 85% Alcohol ~ 12% Everything else ~ 3% FSN 311 Food Processing

7. Wineries FSN 311 Food Processing

8. Classification • Table wine (Natural  wine) • Sparkling wine (contain CO2) – champagne • Fortified wine (added alc.): 14-24% alc. • Red or white 9-14% alc. • Sweet wine:reducing sugar 10 - 100 g/l • Dry wine: reducing sugar < 10 g/l • Called by variety of grapes Vinification เทคนิคการผลิต  FSN 311 Food Processing

9. Red Carbernet Sauvignon Shiraz Durif Merlot Pinot Noir Grenache … White Chardonnay Chennin Blanc Riesling Sauvignon Blanc Semillion … Example grape varieties FSN 311 Food Processing

10. Wine vinification Grapes Fining and filtration Crushed and stemmed SO2 Press Bottling Juice Saccharomyces cerevisiae Fermentation Maturation FSN 311 Food Processing

11. Total Soluble Solids • Use as an indicator for maturation of the grapes • As an approximate basis for calculating the alcohol yield • ~ 90% of soluble solids are fermentable sugar FSN 311 Food Processing

12. How can total soluble solids be measured? • 2 ways • Hydrometers • Refractometry • Brix, Baume • % Brix represent weight of sugar in solution (g of sucrose/ 100 g of liquid) • 1.8 Brix = 1.0 Baume • Baume represent final expected alcohol content of wine FSN 311 Food Processing

13. Must and juice from grapes • Sugar • The sugar content of the grapes depends on the wine style • Acidity • Tartaric and malic acids two main acids • Acidic grape related to high malic acid concentration FSN 311 Food Processing

14. Harvesting • Hand or machine picking Damaging skin can result in enzymatic browning, spoilage FSN 311 Food Processing

15. Crushing and destemming • As soon as possible • To remove the stem from the berries • Crush all berries but not seed (in white wine) • Crushing seed: seed oil can cause rancid odor • Yielding “MUST” FSN 311 Food Processing

16. Simple anatomy of the grape FSN 311 Food Processing

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18. Maceration • Mostly carried in red wine • Grape juice contact with skin and stem • Color extraction (tannins and pigments from skin) • Skin float on top • Not carried out in white wine FSN 311 Food Processing

19. Different kinds of maceration • Pre-Fermentation cold maceration is the period of time used to extract colour and flavour prior to the start of fermentation. This time period can be extended by chilling the macerating fruit to prevent fermentation. • Extended Maceration is the extra time that the red wine is in contact with the skins after primary fermentation has completed. FSN 311 Food Processing

20. Pressing Directly for white wine Red wine after maceration FSN 311 Food Processing

21. Preparing juice for fermentation • Polyphenol oxidase – browning in white wine • Sulphur dioxide (SO2) commonly add to white wine • Prevent browning by inactivate enzyme • Inhibit activity of undesirable microorganisms • 30 to 50 ppm (mg/L) or 70 to 100 ppm (highly contaminate) FSN 311 Food Processing

22. SO2 addition • Often used sodium or potassium metabisulphite (containing 58% SO2) • Want grape juice 500 mL to have 30 mg/L of SO2 from potassium metabisulphite (KMBS): • 58 g SO2 come from 100 g KMBS • Need 0.03 g use (100*0.03)/58 = 0.0517 g/500 mL FSN 311 Food Processing

23. Fermentation • Yeast • Pure culture of Saccharomyces cerevisiae; bought in dried powder • Activation with grape juice several hours before fermentation (108 cell / mL) • Yeast use O2 first few hours, follow by produce CO2 and alcohol • Adding nutrients: Diammonium phosphate (DAP) FSN 311 Food Processing

24. Yeast • Yeast for wine production must be toleranceto • High sugar concentration • Alcohol • Sulphur dioxide • Start fermentation rapidly FSN 311 Food Processing

25. Fermentation • Adding yeast during crushing and ferment during maceration in red wine • Adding yeast 3-5% by volume (previously grown in grape juice) or according to the manufacture • For white wine: adding to juice • Adding nutrients: Diammonium phosphate (DAP) | yeast autolysate | vitamin, thiamine FSN 311 Food Processing

26. C6H12O6 → 2C2H5OH + 2CO2 (1 Glucose  2 ethanol + 2 CO2) • ~ 50% conversion • In reality < 50% by weight FSN 311 Food Processing

27. Temperature of fermentation • Opt. temp. for yeast fermentation is between 10-15 oC (white wine) • Red wine are fermented at higher temperature ~ 25 oC (pigments extraction) FSN 311 Food Processing

28. Stuck fermentation • premature arrest of fermentation • high level of sugar • Cause • fermentation at too high temperature • nutritional deficiency • osmoregulation • ethanol toxicity • low temperature fermentation • too high SO2 • presence of inhibitory substance FSN 311 Food Processing

29. Malo-lactic fermentation • L-malic acid  L-lactic acid • Bacteria Leuconostoc oenos • Increase –pH • ^ pH destabilize • Occur during aging FSN 311 Food Processing

30. Maturation or aging • Usually 1 year for white and 1-2 years for red wines • in large scale production / in tanks and use oak chips • Wood contributes to flavor and characters of wine FSN 311 Food Processing

31. Maturation (continued) • Flavor: vanillin, … • Oak: fill with water purged with SO2 for disinfection • Wine racking (standing) : to separate wine from lees (Lees - The solids left at the bottom of a fermentation) FSN 311 Food Processing

32. Fining of Wines(clearing of wines) • Fining is the process of removing suspended particles from wines and will sometimes be used for softening of wines of phenolic compounds • Common types of fining agents are Bentonite, and egg whites FSN 311 Food Processing

33. Oak barrel Barrel (cask) FSN 311 Food Processing

34. Glass Air Lock   - twin -S - Bubble Wine Thief FSN 311 Food Processing

35. The color of red wine is due to red and purple anthocyanins (first come out from fermentation)--> dark red over 24 months of aging Old wine change from red to red/brown brick White wine pale (light) green/yellow, over 24 months become yellow and over 10 years become brown Color FSN 311 Food Processing

36. Filtration • Filtration is carried out just before bottling • Centrifugation follow by sterile membrane filtration • Sterile filtration with membrane 0.45 – 1.2 micron FSN 311 Food Processing

37. Bottling Purge with inert gas or nitrogen to prevent oxidation FSN 311 Food Processing

38. Closures • Corks; both synthetic and natural • Natural cork has risk of contamination with mold • Screw caps • Proven to be a better seal for wine bottles than corks. FSN 311 Food Processing

39. Capsules • Lead-based capsules very popular until it is banned to use in the late 1980’s. Now wineries use tin-aluminum or aluminum polylaminate. • It is better to have no capsule rather than a bad one. • Very important part of packaging, primarily for consumer appeal. FSN 311 Food Processing

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41. ENJOYING WINE • LIKE WITH LIKE!! ไวน์ขาวและแชมเปญจะเสริ์ฟขณะเย็นๆเล็กน้อย ไวน์แดงจะเสริ์ฟที่อุณหภูมิห้อง อาหารรสเผ็ด แกงไทย ไวน์ขาว FSN 311 Food Processing

42. Beer คือ เครื่องดื่มที่ได้จากการหมัก ข้าวมอลท์ (Malt) มีแอลกอฮอล์ประมาณ 4-6 % การจำแนกชนิดของเบียร์ 1. จำแนกตามชนิดของเชื้อยีสต์ที่ใช้ในการหมัก • การหมักโดยใช้ยีสต์ที่ลอยตัวอยู่เหนือผิวน้ำเบียร์ • เมื่อเสร็จสิ้นการหมัก เรียกยีสต์ชนิดนี้ว่า Top yeast Saccharomyces cerevisiae Ale-type beer FSN 311 Food Processing

43. การหมักโดยใช้ยีสต์ที่จมสู่ก้นถังหมักเมื่อเสร็จสิ้นกระบวนการหมักการหมักโดยใช้ยีสต์ที่จมสู่ก้นถังหมักเมื่อเสร็จสิ้นกระบวนการหมัก • เรียกยีสต์ชนิดนี้ว่า Bottom yeast Saccharomyces carlsbergensis Lager-type beer FSN 311 Food Processing

44. 2. จำแนกตามสีและรสชาติของเบียร์ Black beer ทำมาจาก มอลต์ดำ หรือ คาราเมลมอลต์ ซึ่งทำให้เบียร์มีสีดำ ที่เรียกกันว่าเบียร์ดำ (Dark beer) มีรสชาติและกลิ่นหอมของน้ำตาลไหม้ บางชนิดมีรสชาติเฉพาะตัว เช่น wheat beer ซึ่งมีกลิ่นหอมของข้าวสาลี และมีคาร์บอนไดออกไซด์สูง FSN 311 Food Processing

45. Barley Main ingredients of beer Yeast Hops Water FSN 311 Food Processing

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47. Barley germination -amylase Malt FSN 311 Food Processing

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50. Amber Light Dark Color of malt Milling to Grits This makes the malt easier to wet at the mashing stage and aids faster extraction of the soluble components from the malt during the enzymic conversion. FSN 311 Food Processing