Brewing and baking and mycoprotein

Ancient biotechnologies

(mycoprotein is not ancient!)

Bread making

Basic ingredients are wheat, water, yeast, fat, sugar and salt.

Dough is made by mixing ingredients together.

Dough then ferments at 27oC in a humid atmosphere.

Bread making

The yeast, Saccharomyces cerevisiae, feeds on the sugar breaking it down anaerobically to ethanol and carbon dioxide.

Bread making

The bubbles of CO2 remain trapped in the sticky dough causing it to rise.

Dough is then cut and placed in loaf tins.

Dough then goes through a final fermentation at 45oC.

Bread making

The baking kills the yeast, evaporates off the alcohol and cooks the flour.

A modern bakery can make 10 000 loaves of bread per hour.

Beer Making

Most beers are made from barley and hops.

The process consists of seven stages!

Beer Making

Malting Barley steeped in water Then allowed to

germinate. Gibberellic acid is added

to speed up germination During process amylases

are mobilised (to hydrolyse seeds starch into maltose)

Beer Making

Kilning Malt is gradually

heated to between 65 and 80oC

This kills the embryos without destroying the amylase.

Higher the temp. – the darker the beer.

Beer Making

Milling Barley grains then

crushed into a powder called grist.

Beer Making

Mashing The grist is mixed with

water at 65o C. The amylase breaks down

the starch into sugars. The nutrient rich liquor

(sweet wort) is separated from the spent grains.

The spent grains can be used as cattle feed.

Beer Making

Boiling Hops added for bitter

flavour Further enzyme action

is stopped Full flavour is

extracted.

Beer Making

Fermentation Boiled wort is cooled

to 30oC and innoculated with yeast

Left to ferment for 7 to 10 days.

Sugars turned into alcohol and CO2

Beer Making

Finishing Beer is filtered (spent

yeast sold to make yeast extract – Marmite)

Modern beers are pasteurised, standardised and finally bottled or canned.

Mycoprotein

A food protein made from microorganisms

Mycoprotein

Made from the hyphae of the fungus Fusarium graminearum

Cultured on a solution of

glucose from cereal starch (carbon source)

ammonia (nitrogen source)

mineral salts

choline (promotes longer hyphal growth)

Mycoprotein

Cultured in air lift fermenter (see special hand out from Edexcel)

Culture maintained at 30oC to promote optimum growth rate.

Grown by continuous culture. High in protein but low in fat – a healthy

food?

Mycoprotein

Problem is that it contains too much RNA This has to be removed by enzymes. Tastes of nothing! Fungal hyphae do resemble myofibrils in

meat. Marketed under the name of Quorn.