Food Fermentation

Question 1

Main purpose of food fermentation:

Answer 1

preservation (extend shelf life)

Question 2

3 ways to start fermentation reaction:

Answer 2

1. spontaneous
2. inoculated
3. backslopping

Question 3

4 benefits of fermenting:

Answer 3

1. longer shelf life
2. develops flavours/qualities
3. better nutrient availability
4. possible health-promoting properties (probiotics)

Question 4

sauerkraut is an example of _____ fermentation process. Where are the bacteria sourced from?

Answer 4

spontaneous; occur naturally on vegetable surface

Question 5

True/False: inoculated fermentations involve introducing 1 specific strain into the environment

Answer 5

False; culture can be 1 or many (mixed) species.

Question 6

Advantage of inoculated vs spontaneous fermentations:

Answer 6

more stabilized fermentation reaction (no “wild” species)

Question 7

Adding yogurt to milk to create more yogurt is a type of ___ fermentation.

Answer 7

backslopping

Question 8

What is the effect of continued backslopping?

Answer 8

More contamination, more variation in final product as more bacteria introduced

Question 9

What are the main types of fermentation, and what are the organisms involved? (5)

Answer 9

Acetic (AAB)
Lactic (LAB)
Alcoholic (yeast)
Amylolytic (mold)
Proteolytic (mold)

Question 10

True/False: synthetic vinegar is easier to make, but may not be permissible due to food purity laws

Answer 10

True

biological acetic acid only 10% of production; food vinegar

Question 11

Alcoholic fermentations must be carried out in an ___ environment. Why?

Answer 11

anaerobic

prevent growth of AAB (spoilage)

Question 12

Can “wild” yeast be used for fermentation? What is the effect?

Answer 12

yes

unique flavour profile

Question 13

Why does yeast fermentation extend the shelf life of food?

Answer 13

creates alcohol -> toxic to many species

Question 14

The most common type of fermentation:

Answer 14

lactic acid fermentation

Question 15

lactic acid fermentations in ____ usually do not need inoculation. What types of food do?

Answer 15

vegetables (spontaneous)

milk/dairy (need to “boost” population so can overcome other bacteria)

Question 16

Aspergillus is involved in ____ fermentation.

Answer 16

amylolytic

Question 17

What occurs in amylolytic fermentation? What food products utilize this?

Answer 17

starch broken down to simple sugars
(can then be turned to alcohol)

koji, nuruk

Question 18

What food types are involved in proteolytic fermentation, and what are 2 bacteria types involved?

Answer 18

high protein food (cheese, soybean)

penicillium, rhizopus