Untitled Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of yeast in beer making?

To add a bitter flavor

To enhance the aroma

To convert sugars into carbon dioxide and alcohol (correct)

To provide sweetness

Fermentation is a process used solely for preserving food.

False

Name two types of alcoholic beverages that are made through fermentation.

Beer and wine

The primary ingredient in beer making, which is a grain, is called _____

malted barley Signup and view all the answers

Match the following ingredients in beer making to their roles:

Malted barley = Base ingredient for sugars Hops = Adds bitterness and aroma Yeast = Fermentation agent Water = Solvent for beer ingredients Signup and view all the answers

Which biochemical process is primarily responsible for converting glucose into alcohol during fermentation?

Fermentation Signup and view all the answers

Lactic acid is a product of the fermentation process.

True Signup and view all the answers

What two main varieties of yeast are used in brewing?

Saccharomyces cerevisiae and Saccharomyces carlsbergensis Signup and view all the answers

What is the primary role of yeast in the fermentation process?

Convert sugars to alcohol and carbon dioxide Signup and view all the answers

Anaerobic respiration occurs when the oxygen supply is abundant.

False Signup and view all the answers

What are the two main species of yeast commonly used in fermentation?

Saccharomyces cerevisiae and S. carlsbergensis Signup and view all the answers

The process of converting sugar to alcohol and carbon dioxide is called _____.

fermentation Signup and view all the answers

Which step in wine production involves sorting out rotten or under ripe grapes?

Harvesting Signup and view all the answers

Match the type of wine with its production method:

White Wine = Skins removed before fermentation Red Wine = Skins remain during fermentation Rosé Wine = Juice in contact with skins briefly Signup and view all the answers

Sedimentation is the shortest phase of fermentation.

False Signup and view all the answers

After fermentation, yeast cells settle to the bottom due to ______.

sedimentation Signup and view all the answers

What role does sulfur dioxide (SO2) play in winemaking?

It prevents spoilage and oxidation. Signup and view all the answers

Clean equipment is crucial in winemaking to prevent unwanted bacteria that could spoil the wine.

True Signup and view all the answers

What is the temperature range that is ideal for yogurt fermentation?

28-32 °C Signup and view all the answers

Sweet wine is produced when the fermentation process stops before all of the __________ has been converted into alcohol.

sugar Signup and view all the answers

Match the following components with their roles in yogurt making:

Streptococcus thermophilus = Bacterial culture for fermentation Lactobacillus bulgaricus = Bacterial culture for fermentation Lactic acid = Provides sour taste Homogenization = Prevents fat droplets from separating Signup and view all the answers

What happens to red wine when it is exposed to air?

It becomes oxidized. Signup and view all the answers

Yogurt is fermented at a temperature of 40°C.

True Signup and view all the answers

What is the name for the crushed grapes and juice in the winemaking process?

Must Signup and view all the answers

Study Notes

Microbiology and Biotechnology

Microbiology is the study of microorganisms
Biotechnology is the use of living organisms and bio-processes in industry, technology, medicine, and other fields
Biotechnology often involves genetically manipulating microorganisms to produce products like antibiotics and hormones

Food Industry Applications of Biotechnology

Fermentation is a traditional biotechnology process that uses microorganisms like yeasts and bacteria
Fermentation converts glucose (sugar) into alcohol or lactic acid and carbon dioxide
Fermentation is used to preserve food by extending its shelf life
Fermentation can change the nutritional value of food
Fermentation can improve the sensory qualities of food (flavor, aroma, texture)

Fermented Beverages

There are three main fermented beverage types: beers, wines, and spirits

Beer Making

Beer is primarily made from malted barley, hops, yeast, and water
Malted barley is the base ingredient of beer
Hops add bitterness, aroma, and aid in preservation
Yeast is essential for fermentation, converting sugars into carbon dioxide and alcohol
Commonly used yeast species are Saccharomyces cerevisiae and S. carlsbergensis
Yeast enzymes convert maltose to glucose
Early in fermentation, yeast respires aerobically, oxidizing glucose into carbon dioxide and water, and rapidly dividing
As oxygen decreases, anaerobic respiration begins, oxidizing glucose to alcohol and carbon dioxide
Respiration allows yeast to obtain energy needed for fermentation and sedimentation
Fermentation is the longest phase in beer production, converting sugars into alcohol and carbon dioxide
Sedimentation occurs as yeast cells settle at the bottom of the fermentation vessel due to sugar depletion and begins the transition to dormancy

Wine Making

Wine is produced by fermenting fruit juice, usually from grapes
White wines are made with white grapes and the skins are removed before fermentation
Red wines are made with red/black grapes, and the skins are left for fermentation
Rosé wines are made with red grapes, but the juice is only allowed to remain in contact with the skins for a short period to develop a pink color
Wine making involves five basic steps: harvesting, crushing/pressing, fermentation, clarification (sedimentation), aging/bottling
Harvest time is crucial for quality wine, selecting grapes that are physiologically ripe
Grapes are crushed and pressed, traditionally by foot, now using mechanical crushers
Fermentation converts sugars into alcohol, using naturally occurring yeasts on the grapes’ surface
Clarification removes solids from the wine, such as yeast and grape skins, often through sedimentation
Aging develops complexity and flavor, and may involve the use of oak barrels
Sulfur dioxide is added as a preservative to prevent oxidation and spoilage during wine-making
Clean equipment is vital in wine-making to avoid contamination and ensure quality
Sweet wine is produced when fermentation is stopped before all the sugar is converted to alcohol
Red wine can oxidize when exposed to air, reducing its quality

Fermented Foods

Yogurt Making

Yogurt can be made from cow, sheep, or goat milk
Most yogurt is made with a mixture of Streptococcus thermophilus and Lactobacillus bulgaricus
Yogurt is fermented at 28-32 °C
Milk is homogenized to break up fat droplets and prevent separation
Then milk is pasteurized to kill harmful bacteria
Starter cultures of bacteria are added to ferment the milk
The bacteria convert lactose (milk sugar) into lactic acid, coagulating casein (milk protein) to create the thick creamy texture
Fermenting works best at 40°C, then the yogurt is cooled to 5°C to stop the process
Lactic acid gives yogurt its sour taste
Sterile conditions throughout the yogurt-making process are important to prevent contamination and unwanted flavors

Questions

Which grain is most often used to make beer? Malted barley
How is the beer colour derived? The color comes from malted barley, which can be roasted to different degrees, influencing the color of the final beer
What are the two important by-products of fermentation? Carbon dioxide and alcohol
In the winemaking process, what is the name for the crushed grapes and juice? Must
What gives red wines their dark color? The pigments present in the grape skins, which are left in contact with the juice during fermentation.