Fermentation

Question 1

Microbes and fermentation

Answer 1

Carry out respiration
While aerobic makes most ATP microbes can live in environments where this is not possible

Industry select right conditions to be most useful to it

Question 2

Anaerobic respiration Pathway (ethanol)

Answer 2

Glucose
Pyruvate
2 - acetyl-CoA
2 Acetaldehyde
2 Ethanol

(Net gain - 2 ATP and 2 NADH)

Question 3

Anaerobic Respiration Pathway (Lactate)

Answer 3

Glucose
2 Pyruvate
2 lactate

Question 4

Products of carbohydrate anaerobic respiration

Answer 4

Acid
Alcohols
CO2

Question 5

Example of two step pathway

Answer 5

Ethanol further fermented aerobically to make vinegar (acetic acid) by acetobacter

Question 6

Improving Nutritional Value using fermentation

Answer 6

Starchy food can be nutritionally enhanced via fermentation

Sourdough
Tempeh
Banku
Natto

Question 7

How can fermentation improve nutritional value

Answer 7

Example Sourdough
Mixed fermentation with yeast and bacteria
Symbiotic relationship - meaning waste of one micro-organism used by others

Produces a wide range of variety of short-chain fatty acids - provide characteristic taste and reduce risk of spoilage

Sourdough also further release enzymes that degrade phytate - plant compound that binds phosphate, calcium, iron and zinc making less available to digest

Question 8

Importance of improved nutrition

Answer 8

Building up microbial biomass results in improved AA composition

With better biological value

Micro-organisms can synthesis all AA including Vit K and Vit B

Question 9

Microbes and Cheese Starter Culture

Answer 9

Lactic acid bacteria (LAB)
Produce lactic acid
Sometimes produce carbon dioxide, Taste compounds pH compounds

Question 10

Carbon dioxide Production from cheese starter cultures

Answer 10

Produces bubbles/holes

Swiss Cheese

Question 11

Taste Compound production from cheese starter culture

Answer 11

Acetaldehyde
Diacetyl
Acetone
Ehtanol

Question 12

Acid compound production from cheese starter culture

Answer 12

Acetic acid
Butyric acid
Propionic acid

Question 13

Mesophilic bacteria

Answer 13

Optimum growth - 33 degrees
Lactococcus and Leuconostac species

Cheddar, Gouda, Cottage Cheese

Question 14

Thermophilic

Answer 14

Optimum Growth Temperature - 40-45 degrees

Lactobacillus and Streptococcus

Emmenthal, Gruyere, Feta and Mozzarella

Question 15

Blue Mould specie

Answer 15

Penicillium Roquefortii

Question 16

White Mould specie

Answer 16

P. Camambertii

Question 17

Orange Grind

Answer 17

Brevibacterium

Question 18

Ripening of cheese

Answer 18

2 weeks to 2 years
Changes texture and taste due to activity of microbial enzymes on fat protein or carbohydrate in curd
Not sterile
If not pasteurised a cheese must be ripened for 60 days

Question 19

Proteolysis

Answer 19

Proteolysis where proteins are broken down into amino acids

Peptides and amino acids can activate taste receptors

Question 20

Glutamic acid taste

Answer 20

Umami

Question 21

Methionine taste

Answer 21

Sweet

Question 22

Phe-Pro taste

Answer 22

Bitter

Question 23

Lipolyisis

Answer 23

Formation of fatty acids, esters etc

Moulds a responsible for characteristic smell by forming alkan-2-ones compounds from lipids