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33 Cards in this Set

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What is the SO2 treatment of must meant to do?
It is antimicrobial and controls wild yeast from changing fermentation (controls)

Disrupts grape cells and releases compounds into wine

Prevents oxidation
Explain the physiology of wine yeast and how they are useful in winemaking
Can grow & divide in aerobic conditons, and can survive in anaerobic conditions.

They are resistant to sulphites and alcohol

The yeast produce acedaldehyde and ethanol in presence of sugars

Yeast gives winemakers flexibility in how fast/slow they want the fermentation to proceed. If is going to slow, can add O2 which will further activate the yeast and promote division.
Explain the process technology for red, rose, white, and champagne
Red: Undergo fermentation with skins and must together

Rose: Pomace from juice is left long enough to produce rose color, then pressed and fermentaiton continues

White: White grapes pressed with minimal contact with skins.

Champagne: A white wine fermentation, except small amount of extra sugar is added after fermentaiton to the bottling step, adding carbonation. Cork and bottle usually much more hardy than regular wine bottles.
What is the SO2 treatment of must meant to do?
It is antimicrobial and controls wild yeast from changing fermentation (controls)

Disrupts grape cells and releases compounds into wine

Prevents oxidation
Explain the physiology of wine yeast and how they are useful in winemaking
Can grow & divide in aerobic conditons, and can survive in anaerobic conditions.

They are resistant to sulphites and alcohol

The yeast produce acedaldehyde and ethanol in presence of sugars

Yeast gives winemakers flexibility in how fast/slow they want the fermentation to proceed. If is going to slow, can add O2 which will further activate the yeast and promote division.
Explain the process technology for red, rose, white, and champagne
Red: Undergo fermentation with skins and must together. Pressed after fermentation

Rose: Pomace from juice is left long enough to produce rose color, then pressed and fermentaiton continues

White: White grapes pressed with minimal contact with skins.

Champagne: A white wine fermentation, except small amount of extra sugar is added after fermentaiton to the bottling step, adding carbonation. Cork and bottle usually much more hardy than regular wine bottles.
How many fermentations are there in winemaking? What are characteristics/organisms associated with each?
There are two fermentations:

1) Lactic Acid Fermentation
Accomplished by yeast: saccaromyces cerevisiae

2)Malolactic Fermentation
Occurs after transferred to oak barrels for aging process. Malic Acid, a tart acid is produced. To combat its effect, Oenococcus oenus is added which converts malic acid to lactic acid
Describe the Fermentation of Wine. How is it physically done? What is a quicker way to add woody tastes to the wine without aging?
Juice is poured into stainess steel tanks

primary yeast fermentation

racking - carefully siphoning liquid out of tank not getting too much yeast
(if wait too long to rack, yeast can autolyze and release unwanted compounds)

Aging in oak barrels with maleolactic fermentation

TO SPEED UP AGING PROCESS, CAN USE WOOD CHIPS IN TANK RATHER THAN BARRELS
How are molds used in wine making?
Mold; Botritis cinera

The mold histroically infected grapes and ruined whole vinyards. However, the mold dehydrates and concentrates sugars in grapes, creating the dessert wines.

Botritis cinera is now deliberately added to grapes to create modern day dessert wines.
How is beer made?
See slides.
How is whiskey made?
cereal fermentation of barley followed by several distillations and aging in a wooden barrel.

Can be blended with rye and or barley malts
How is Brandy made?
Distillation from wine followed by wood aging
How is vodka made?
primary fermentaiton of any fermentable carbohydrate (grain and potato most common) followed by multiple distillations

Column and filtration to remove impurities
How is tequila made?
cactus (agave) bacterial fermentation using Zymomonas mobilis

Distilled twice
How is port wine made/where is it made?
Wine fermentation is stopped at desired sweetness and mixed with brandy.

Alcohol in brandy kills yeast, stopping fermentation and preserving sweetness. Alcoholic content is about 20%

Wine is aged.

Comes from Portugal
How is Sherry made? What is different from port wine? What is the solera system
Same as Port wine, except made in Spain and aging system (known as solera system).

A solera system is a complex of wood barrels where a portion of the wine from the last barrel of the series is removed and bottled. Then the last barrel is filled from the next-to-last barrel, etc., until the first barrel is filled with new wine. The barrels are then left to age until the process is repeated.
How is Madiera fortified wine made?
Full wine fermentation fortified with brandy and heated in aerobic conditions to 40-50C. Gradually cooled during several years of aging.
How is regular vinegar made?
anaerobic yeast fermentation of raw materials (grapes, apples) for alcohol production

secondary fermentation using Acetobacter produces acetic acid (vinegar) via secondary aerobic fermentation
How is traditional balsamic vinegar made?
Trebbiano grapes are separated into must and reduced on low heat (concentrates). Liquid put into small wooden wine barrel. First year of aging will feature yeast fermentation of the sugars. Each year the liquid is transferred into a new, slightly smaller wooden barrel that is made of a different wood. The aeration from pouring the vinegar into a new barrel each year sets of acetic acid fermentations each year.

There is no deliberate inoculation of any cultures. All traditionally done.
What alcoholic fermentation are malt based?
Beer and whiskey
What alcoholic fermentation are grape based?
Port, Sherry, Mediera, Wine, Brandy
What are the workhorses of the dairy fermenters? What are characteristics of each? How do you differentiate them?
Lactococcus lactis subsp lactis:
Fast acid producer, produces bitter flavors

Lactococcus lactis subsp cremoris:
Slower acid producer, creates more desireable end product

Differentiated by maximum temp. subsp lactis max temp is 40, other is 38
What are the main mesophilic LAB dairy starter culture? What are their main applications?
L. lactis subsp lactis
L. lactis subsp cremoris

L. lactis subsp lactis biovar diacetylactis
BUTTERMILK SOUR CREAM, METABOLISES CITRATE INTO DIACETYL

Leuconostoc cremoris (also prod diacetyl)
What are the main thermophilic LAB dairy bacteria? What are their main applications?
Streptococcus thermophilus
cheese yogurt

Lactobacillus delbrueckii subsp bulgaricus
yogurt cheeses

L. helviticus
cheese
What are other cultures (bacteria and mold) used in dairy fermentations, and what are they used for?
Propionibacterium shermanii:
swiss cheese - produces Co2 (holes) and nutty flavor

Brevibacterium linens:
used for surface ripening (aerobic)

MOLDS
Penicillium roqueforti
glycolysis, flavor

Penicillium camembert
brie mold on the outside (aerobic)
Describe how LAB get their energy source of Lactose into a useable form
Lactose is phosphorylated via the PHOSPHOTRANFERASE SYSTEM and can then cross the cell membrane.

Lactose is now Lactose-6-phosphate.

Lactose-6-phosphate is then broken down into glucose and galactose by the enzyme Phospho-B-galactosidase

The glucose is then broken down by the cell into pyruvate and through an anerobic fermentation, converted into lactic acid (via lactate dehydrogenase)
LAB cannot make all their own necessary amino acids to survive. Therefore they must process them from their surrounding environment. How is this done?
VIA THE PROTEOLYTIC SYSTEM
Casein (from milk) is broken down by Extracellular Protease (PrtP) into peptides.

Peptide transport systems bind the peptides and internalize them.

Peptidases inside cell breaks the peptides down further into useable amino acids
What is a unique aspect about LAB in terms of how their genes are coded? What are disadvantages of this?
Most of their metabolic functions are encoded on plasmids (circular (sm) piece of self replicating DNA). THese include Lactose and Citrate Metab, Proteolytic system, phage resist, and bacterocin production
How is coagulation accomplished in cheese production?
Casein (4 parts, one hydrophilic) migrates into micelles (kappa casein stabailizes molecule so that it mixes in milk). Chymosin (enzyme) cuts kappa casein into para-kappa-casein, destabilizing the molecule, and causing casein to precipitate out of solution. Chymosin activity is stimulated by acid production of LAB.
What enzyme is rennet is specifically used for separating milk into whey and curds? How is it produced?
Chymosin is the enzyme. It is produced by GMO, usually ecoli and yeasts. It is thus called recombinant chymosin.
What type of cheese is Feta, what bacteria are used for a starter?
It is a fresh/unripened cheese. Lactococcus lactis subsp lactis and cremoris are used. Like a cheese curd.
How is cheddar made, what are the starter cultures?
It is a ripened cheese that uses Lactococcus lactis subsp lactis and cremoris. Sometimes helviticus is used as well.

Cheese must be pressed and formed and then is ripened in a 15˚C room. Ripening using causes secondary fermentations that are usually proteolytic, creating peptides with characterisitic flavors
How is swiss made, what are the starter cultures?
Swiss is ripened cheese that uses Streptococcus thermophilus, Lactobacillus helviticus, and Propionibacterium spp. The Propionibacterium produces CO2, giving the cheese holes and a characterisitic nutty flavor.