FUNGAL METABOLISM
(REFERENCE TO FOOD AND BEVERAGES)
Amjad KhanAfridi
Lecturer,Department of Health& Biological Sciences
Chapter # 07

Introduction
 Fungi metabolism consists on a series of reactions (biochemical reactions)
constantly occurring inside the cells to keep it alive and active and in the results
biosynthesis of a huge number of compounds.
 These compounds area usually divided into primary and secondary metabolites.
 Primary metabolism is common to several species and usually produces
compounds with the function of assuring fungi growth and development.
 Primary metabolites are involved in the growth, development, and reproduction
of organisms.
 The primary metabolites consist of vitamins, amino acids, nucleosides and
organic acids

Cont…
 Secondary metabolism refers to the production of
compounds that are not indispensable during
fungi development.
 Secondary metabolites are commonly referred as
"natural products“ and have been extensively
utilized in the pharmaceutical, cosmetics and food
industry.
 Alkaloids, steroids, antibiotics, gibberellins, and
toxins are the secondary metabolites.

Cont…
 The metabolism of filamentous fungi is capable of
producing numerous secondary metabolites that can used
for the development of functional foods, nutraceuticals, and
bioactive substances that can be used as medicines.
 Fungal metabolism is usually fast and the scale up is
usually easier than in some other processes.

Cont…
 The use of the term food-making process is
used here to mean those food products that
require the aide of fungi in their production.
 For example, the one with which you are most
familiar is baked bread.
 The yeast is utilized in making the dough rise so
that bread will come out light and fluffy.
 Without yeast, bread would be much denser and
harder.

Moldy Cheeses
 Although the sight of mold in food is a sign
that it is contaminated and should be
discarded, there are some foods in which
the presence of visible fungal mycelium is
very much a part of the product.
 Among these are some of our cheeses.
 Two of the most familiar examples
are Camembert and Roquefort, also known
as blue cheese.

Cont…
 These cheeses are among the favorites among
gourmets.
 These cheeses are made from two species
of Penicillium (P. camemberti & P. roqueforti)
 Camembert cheese prepared with P.
camemberti while Roquefort cheese prepared
by P. roqueforti.

Roquefort cheese
 In making Roquefort cheese, in Roquefort, P.
roqueforti is added to the cheese made from sheep's
milk.
 The cheese is salted and holes made throughout the
cheese for aeration, and left for several days.
 The cheese is then allowed to age for two to five
months.
 Americans like the cheese to be new and mild, while
the French prefer it to be very old and strongly
flavored.

Camembert cheese
 Camembert cheese is quite different in appearance.
 The fungus involved in the manufacture of this
cheese is Penicillium camemberti.
 The mycelial growth of this species occurs only on
surface of the cheese and does not work its way
inside to form veins as in P. roqueforti.
 Fable has it that the process for making this cheese
was a relatively recent.
 It's creation has been credited to Marie Harel, in
1791, a native of the tiny village of Camembert, in
Normandy.
21st April, 2022

Shoyu (soy sauce)
 Shoyu (soy sauce) is probably the most familiar Asian food
product in this country, but probably few people know
how it is made.
 All of you probably are aware that it is made from
soybeans.
 The soybeans are cooked mixed with wheat flour, pressed
into cakes, and placed in a special room where it is
inoculated with Aspergillus oryzae (the same species used
in making saki).
 The mixture is then incubated for three days.
 If all goes well the cakes will become covered with yellow
mycelial growth.
25th May, 2022

Koji
 The molded cake is referred to as Koji, which is a
fermentation product of grains.
 The koji is now mixed with salt and water and is
now referred to as the Moromi.
 The moromi is then inoculated with a
bacterium, Peiococcus soyae, which will ferment the
mixture for approximately 6 months.
 The aged liquid which is pressed out is the soy
sauce.
 Because it is a fermentation product, soy sauce does
not spoil when left out.

Miso
 Miso is a Japanese word for fermented soybean
paste.
 Miso is not usually consumed by itself, but is
dissolved in water as a base for soup or used as a
flavoring agent.
 Miso fermentation consists of washed, polished
rice, which is steamed and inoculated
with Aspergillus oryzae.
 The inoculated rice is incubated for 48 to 50 hours
at 40 C or below, resulting in rice koji.

Cont…
 The carbohydrates and proteins of the inoculated rice
are digested by the fungus and converts it to sugars
and amino acids.
 The rice koji is then inoculated by yeasts and bacteria
and allowed to ferment for about a week at 28 C and
then raised to 35 C for about seven months.

16
25th May, 2022