K.K Lecture 5&6 Flashcards
Why develop Mycoprotein (aka fungal protein)?
- world population increasing
- animal protein is expensive
- diseases are caused due to lack of protein
Why should we develop a novel food?
- it has high nutritional value
- acceptable to public
- it uses cheap raw materials
Why should we use filamentous fungi?
- it is well studied
- it has low nucleic acid content
- it is fibrous
- it is safe to use
What are the materials and fungi used in single cell protein (SCP) production?
look at slide 8
Mycoprotein screening
- screening : Ranks, Hovis McDougal (RHM)
- initially looked at penicillium spp.
- 1968-1971 : 3000 soil isolates sample tested
- isolate A3/5 : this was isolated on day 3 of screening, 3 miles from the lab in Buckinghamshire, England
Fusarium gramineraum
- growth rate: MGT 3.5 hours
- optimum temp: 30 degrees C
- optimum pH: 4.5-8.0
- the yield is 0.54 on glucose
- you can grow on glucose and get 54g fungus wet weight and 45% of the 54g is protein which is most likely edible
Mycoprotein fermentation process
- continuous cell cycle
- essential for productivity
- cycles : 3000 hours
- air lift fermenter
- keep cultures in exponential phase as it will actively grow
- use starch as food stock
Why was starch used in the mycoprotein fermentation process?
because it is the cheapest raw material that the farmer was spraying on the field so the fungus was selected on starch
What was the problem with the starch?
the RNA content was too high and eating food with excessive RNA content will result in uric acid. the RNA gets broken down in the liver to uric acid
How can you reduce the RNA content?
- temperature shock (30 mins at 64 degrees celsius)
- RNA reduces from 10-2%
- this will increase the protein
Airlift fermenter
look at slide 12
What is the problem with the fermentation of mycoprotein and how can we control it?
- the appearance of highly branched variant after 400 hours arises spontaneously
- this affects the texture of the final product
- can control it by limiting nutrients, pH and selection
How can we harvest mycoprotein?
by using fungal biomes which is easy to harvest
Was the safety of mycoprotein checked? if so how how was it done?
- yes it was, it was done by doing animal and human trials
- there was a range of animal species and 2500 humans
- there was no mycotoxins present
Food formulations of mycoprotein
- the food value is equivalent to milk protein
- it has 75% food value of steak
- there is low fat and no cholesterol
- Mycoprotein had a fibrous texture like chewing meat or a ‘mouth-feel’
Quorn
- launched in 1985
- low fat, it is a healthy option
- it took 15-20 years to get to the market
What factors affect the production of fungal enzymes?
- fungus
- strain selection
- fermentation process
What factors does the fungus need to be to be used for production?
- needs to be non-pathogenic
- non-toxin producer
- needs to be generally regarded as safe (GRAS)
What factors does the strain selection need to be to be used for production?
- needs to enrich and screen for high producers
- reverse catabolite repression - need an inducer
What factors does the fermentation process need to be to be used for production?
- when it’s in a solid state it can cause problems
- the batch needs to be controllable
- the medium needs to be cheap and abundant (C-source: barley, corn. N-source: yeast extract)
- yield must be high
- location of enzyme: is it intra or extra-cellular?
Why use fungi?
look at slide 3 (lecture 6)
- fungi need a wide range of enzymes to grow in the environment
What are the fungal enzymes?
look at slide 6 (lecture 6)
Application of enzymes in fruit juice maceration?
- pectinases, cellulases, hemicelluloses used to extract and purify fruit and vegetable juices
- alpha-amylases and amyloglucosidase remove haze from apple juices (to get clear and not cloudy apple juice)..
- pectinases ease peeling of citrus fruits.
Tanning industry
- production of leather
- proteases and lipases from Aspergillus species to degrade keratin of hair in hides
