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Alcoholic beverages - Coggle Diagram
Alcoholic beverages
Beer
Ingredients
- Cereals: Barley, sometimes wheat
1. Malting
- Germination
- Formation of certain enzymes
- Break-down of cell walls and protein matrix
- 14-18 °C
- Steeping
Malting: Enzyme activities formed
- β-(1,4)-glucanases (cellulases), β-(1,3)-glucanases
- Proteases
- Amylases; α-amylases, β-amylases
- Lipases
2. Kilning
- Reduction of water content
Maillard reaction
- 100C
- Aminos and sugars -> color/flavour compounds
- Dimethyl sulfide DMS
3. Mashing
- Grist in water at different temps
- Degradation of starch
- Maltose (40-45%)
- Maltotriose (11-13%)
- Glucose (5-7%)
- Degradation of cell walls + protein in malt
- Mashing vessels, heat jackets
4. Lautering
- Wort separation
- Lauter tun
- Mash filter
5. Boiling and hops addition
- Concentration of wort
- Inactivation of enzymes
- Precipitation of proteins
- Sterilization
- Removal of undesired flavour compounds; dimethyl sulfide (DMS)
Hops added
- Flavour components
- Resins, tannins, essential oils
- α-acids -> isomerisation: iso-α-acids -> bitterness
- B-acids
- Conservation
6. Fermentation
- Carbohydrates -> ethanol
- pH drop
- Yeast growth
Top-fermenting yeasts (ales)
- Saccharomyces cerevisiae
- 15-25° C
- Flocculation - float to the top
- Clean flavors
Bottom-fermenting yeasts (lager)
- S.pastorianus
- 5-10 °C
- Flocculation (clumping together of yeast cells) - sediment at bottom
- Fruity or complex
Specialized strains
- (e.g., Brettanomyces for sour beers)
- Add unique flavors
Domesticated beer yeast
- Utilization of maltotriose
- Less prod. 4-vinyl guaiacol
- Ethanol production not that significant, higher tolerance
Flavour components
- Esters (fruity),
- Aldehydes,
- Higher alcohols
- Phenolics
- Diacetyl
Sake
Definition
- Alcoholic beverage
- Rice, water, yeast, and koji mold
Process
- Rice Polishing
- Removes lipids and proteins -> flavor + fermentation efficiency
- Koji Preparation
- Rice with A. oryzae -> produce enzymes for starch breakdown
- Fermentation
- Multi-stage fed-batch, ethanol production
- Final Steps:
- Filtration, pasteurization, and maturation
Characteristics
- Alcohol,
- organic acids
- esters
Moto
- Anaerobic submerged fermentation
- Propagate desired yeast (S.Cerevisiae) while keeping contaminating microorganisms low
Crabtree effect
- Definition: When yeast produces ethanol (aerobic conditions + high glucose conc) instead of biomass through TCA cycle
- Mechanism: High conc glucose -> accelerates glycolysis -> ATP production -> reduces need of oxidative phosphorylation -> decreases oxygen need
- Evolutionary Aspect: Evolved as a competitive mechanism exploiting ethanol's toxicity to deter rivals in sugar-rich environments.
ATP in yeasts
- Respiration
- 18 ATP / glucose molecule
- Fermentation (Glu -> pyru -> ethanol)
- Glycolysis
Theories behind
- Duplication of ADH -> Adh1 (form ethanol) and Adh2 (uptake ethanol)
- Make-Accumulate-Consume Strategy:
Yeasts defend resources by creating ethanol and later metabolize it.
- Rate/Yield Trade-Off:
ATP production prioritizes rate over yield to gain competitive fitness.
- Crabtree-positive yeasts like Saccharomyces cerevisiae produce ethanol and ATP rapidly
- Crabtree-negative yeasts maximize ATP efficiency, slow
Alcoholic fermentation
- Ethanol conc limited by sugar conc and ethanol tolerance of yeast
- Mainly Saccharomyces spp
- Key metabolic yeast trait: ferment sugars into ethanol