1.3: Biotechnology in Food Production Flashcards
1
Q
What are examples of industrial microbial products?
A
- health and food products (lysine, vit B12)
- pharmaceuticals (oestrogen, cortisone, penicillin)
- food (mycoprotein or Quorn)
- beer/wine
2
Q
What are the three stages of setting up an industrial process?
A
- laboratory scale
- pilot plant scale
- industrial plant scale
3
Q
What does the laboratory scale consist of?
A
- Grow microorganism which has been found to make a useful product in small flask (200cm3)
- Check that product can be produced
- Purity of product is checked
- Optimum conditions for growth determined
4
Q
What does the pilot plant scale consist of?
A
- A small fermenter (200-500dm3) is used to culture the microorganism
- Check that reaction works when scaled up
- Check that any gases produced can be ventilated
- Optimum operating conditions are confir
5
Q
What does the industrial plant scale consist of?
A
- Microorganism is grown in a large industrial fermenter (bioreactor)
- This is thousands of dm3 in volume
6
Q
What are the problems encountered with scaling up?
A
- Small scale fermenters are stirred by a small electric mixer, using a small quantity of electricity
- If it were scaled up directly in proportion to the vessel the mixer would be too large, need too much electricity and generate too much heat. Therefore alternative methods of mixing may be needed
- Large volumes of liquid are slow to heat and cool
- Maintenance of sterile conditions
Difficulties in maintaining constant flavour/quality - Errors can lead to loss of several days production
7
Q
Label the fermenter/bioreactor
A
8
Q
what are the functions of a stirrer?
A
stirs the contents of the fermenter so that cells are constantly brought into contact with fresh medium
9
Q
What is the function of the water jacket?
A
contains cold water which circulates constantly to keep the contents of the fermenter from over heating
10
Q
What is the function of the acid/alkali inlet?
A
maintains a constant pH for optimum growth conditions
11
Q
What is the function of the sterile air inlet?
A
allows sterile O2 in if organisms are aerobic or adds CO2 if organisms are anaerobic
12
Q
What is the function of the air inlet?
A
allows venting of waste gases
13
Q
What is the typical growth curve for bacteria?
A
14
Q
What is the difference in fermenter between batch and continuous culture?
A
- batch - Carried out in a closed fermenter
- continuous: in a closed fermenter
15
Q
What is the difference in addition of microorganisms and nutrient medium between batch and continuous culture?
A
- Batch: Microorganism and nutrient medium are added at the start and product is extracted at the end
- Continuous: Nutrients added and products removed continuously
16
Q
What is the difference in growth curves between batch and continuous culture?
A
- Batch: Short phase of exponential growth
- Continuous: Phase of exponential growth of microorganism maintained
17
Q
How hard is it to monitor and maintain environment in batch and continuous culture?
A
- Batch: Easy to set up and control the conditions
- continuous: Can be difficult to monitor environmental conditions
18
Q
What happens if contamination occurs in batch and continuous culture?
A
Batch: Only 1 batch lost if contamination occurs
Continuous: if contamination occurs, there is a considerable waste. costly
19
Q
What can happen in continuous batches?
A
Foaming, clumping and blockages may occur
20
Q
What is the growth curves of a microorganism grown in a continuous fermenter?
A
21
Q
What is beer made from?
A
Malted Barley
22
Q
What is the first step of the beer making process?
A
- Grains are soaked for 2-3 days
- Incubated at 13 – 17 ° C for 10 days
- Grain germinates and produces amylase enzymes which convert starch to maltose
23
Q
What is the second step of the beer making process?
A
- The temperature is raised to 40 – 70 °C
- This denatures enzymes and stops germination
- This is often carried out by specialist maltsters and the malt is sent to the brewery
24
Q
What is the third step of the beer making process?
A
- The roasted grains are cracked open by passing between rollers
- The crushed malt is called grist
- This is mixed with hot water in a large container called a mash tun
25
How long does the mash stand for?
2 hours so that the sugars dissolve, then passes into another vessel where the sugar liquid is drained off
26
What happens to the grain when the wort is drained off?
- The grain is sprayed with hot water to wash out the sugars
- The spent grain is sold for cattle feed
27
Why is the hop added to the grain?
To add flavour
28
What happens to the wort and hops in beer making process?
- The wort and hops are boiled in a copper vat for several hours
- The wort is separated from the hops which are then sold for manure
29
How is wort cooled in the beer making process?
By passing it through heat exchangers
30
What yeast is added to the beer process?
Saccharomyces cerevisiae for beer and Saccharomyces carlsbergensis for lager
31
Where do larger and beer yeasts grow?
at the bottom of the vessel and beer yeasts grow on the surface of the wort
32
What do they do to the yeast once added?
- Initially the brew is stirred – the yeast respires aerobically
- Allows yeast to replicate
- Temperature related to type of yeast typically 15 -20 oC upto 25 oC
- Conditions then become anaerobic
33
What does years convert sugar to?
Ethanol and carbon dioxide
34
How many days does yeast wait to be separated?
2-5 days, some is also used for the next batch
rest is sold
35
What is the difference between traditional and modern beers in terms of storage?
- Traditional beer is stored in barrels.
- Modern beers are filtered, pasteurised and standardised and canned and bottled
36
What are modern advances in yeast production?
- New strains of yeast developed to tolerate high alcohol levels and improve flavour
- Amylases added to speed up the breakdown of starch to sugar
- Low carbohydrate beers are being produced
37
What is mash in beer production?
grist which has been heated to 62-68 degrees hot water
38
What is wort in beer production?
the sugary liquid removed from heated mash
39
What is grist in beer production?
malt passed between rollers to crush the grains
40
What is malt in beer production?
barley that has been soaked in water for 2-3 days then incubated at 13-17c for 10 days
41
What is yeast sold for?
Used for the next batch of beer or yeast extract (eg marmite)
42
What is spent grain used for?
Cattle fodder
43
What is carbon dioxide waste used for?
sold for general use
44
What is spent hops waste used for?
hops manure
45
Label the diagram of saccharomyces cerevisiae
46
What is Quorn and what is it made from?
meat alternative, fungus grown in a continuous fermenter (Fusarium venenatum)
47
What is added to the continuous fermenter in mycoprotein production?
- The growth medium used is mainly glucose
- Ammonium compounds are added to provide a nitrogen source
- Choline is added as a growth factor to increase hyphal length
48
what is the fusarium added to?
sterile culture medium
49
What is the optimum temp for mycoprotein production?
30 degrees
50
What is extracted from the fusarium culture in the industrial process?
CO₂ and excess heat
51
How is the fungal hyphae removed?
by centrifuge
52
How do you reduce the RNA levels?
using enzymes (RNAses)
53
What happens after RNA levels are reduced?
mycoprotein is then filtered, steam is used to kill the fungus and wash it
54
How do you bind mycoprotein together?
Mix it with egg white to bind it together and flavours to make dough which is made into products
55
Process of mycoprotein
56
What is used to produce beer?
dried yeast
57
What is brewers yeast rich in?
water soluble vitamins -
b complex vitamins, riboflavin, niacin
58
What can spent yeast be used to make?
Marmite
59
Who discoversd how to convert spent Brewers yeast into a food product?
German chemist, called Justus Von Liebig
60
Yeast Autolysate - yeast production
How does it work?
He left the spent brewers yeast to undergo a period of self-digestion “autolysis”
Enzymes in the yeast break down its proteins, nucleic acids and carbohydrates
This occurs naturally but will happen faster if the yeast is heated to 50oC with the addition of salt
After 24 hours the mixture is filtered and concentrated into a thick paste
61
Where is yeast allowed to autolysate?
In large tanks/copper vats
62
What is the waste yeast cell walls used for?
Animal feed
63
How is the liquid contents separated from the yeast cell walls in autolysate?
by centrifugation and filtration
64
what are the final steps of yeast production?
Water is evaporated from the yeast autolysate in vacuum condensers until the correct consistency is achieved
Vegetable extracts are then added for flavour and it is packed into sterile glass jars
65
How are yeast hydrolysates made?
- Made by boiling the yeast with hydrochloric acid to hydrolyse the proteins to amino acids
- Then neutralized with sodium hydroxide
- Filtered and concentrated into a thick paste
- Salty flavour comes from the salt produced when acid is neutralised
66
What are the uses of yeast extracts?
Both autolysates and hydrolysates have a meaty flavor and are used as food additives eg in soups, hamburgers, crisps
67
Compare yeast autolysates and yeast hydrolysates production (similarities)
Require yeast as a substrate
Require breakdown of yeast proteins
Require heat for their production
Contain salt
Require a filtration/condensation stage
68
Compare yeast autolysates and yeast hydrolysates production (differences)
