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Yeast and its Food Application
Syeda Fatma H. Bukhari
Yeast
 Eukaryotic (mostly unicellular)
 Classified1.under
the kingdomand
Fungi. vigorous
Predictable
 They are capable
of obtaining their
required energy in
fermentation
capabilities
2. Tolerance
towards
aerobic conditions
(respiration)
as well as high
anaerobic
alcohol and sulfur dioxide
conditions (fermentation).
levels
 “Yeast” as a word comes from Old English (gist or gyst) and
3. Capability of thriving between
from the Indo-European root yes-, meaning foam, bubble or
pH 2.8 and 4 (normal wine pH)
boil.
 Saccharomyces cerevisiae is the most common yeast species used
in processes like brewing and baking.
Types of Yeast
Brewer's
yeast
Torula
Nutritional
yeast
Baker's
yeast
Types of Baker’s Yeast
Cream yeast
• Suspension of
yeast cells in a
liquid
• Closest forms
to the yeast
slurries of the
19th century
• Used in
industrial
bakeries
Compressed
yeast
• Cream yeast
with most of
its liquid
removed
• Available in
the form of
“cake yeast”
• Low shelf life
Active dry
yeast
• Commonly
available
• Coarse oblong
granules of
yeast
• Rehydrated
before use
• Long shelf life
• More sensitive
towards
thermal shock
during
cooking
Instant Yeast
Rapid Rise
Yeast
• Higher
percentages of
live yeast cells
per unit
volume and
the granules
are also
smaller
• Shelf life is
shorter than
active dry
yeast
• Ascorbic acid
• Does not
require
rehydration
• Variety of
dried yeast
• Smaller
granules
which aid the
yeast to
dissolve faster
in the dough
• Provide a
greater carbon
dioxide
output which
allows faster
rising
• Bread making
machines
Nutritional Yeast
 Deactivated yeast, often a strain of Saccharomyces cerevisiae
 Used as dietary supplements.
 Nutritional yeast is rich in many basic nutrients that the body
requires: B vitamins (excluding B12), chromium, minerals,
amino acids and vitamins (excluding A, C and E).
 Yeast also has high phosphorous content.
 There are two primary sources from which nutritional yeast
is derived: from brewing beer and from whey, molasses,
blackstrap or wood pulp
Uses of Yeast Extracts
 Yeast extract is the name given to various processed yeast products




obtained by extracting the cell contents (or through removal of
cell walls).
They are used as food additives and flavorings, often to create
savory flavors and umami taste sensations.
Yeast extracts are found in a large variety of packaged food
including frozen meals, junk food, crackers, gravy, stock and
more.
Liquid form of yeast extracts can be dried to produce a light paste
or powder.
Glutamic acid is one of the most widely used yeast extracts and is
produced from an acid-base fermentation cycle.
Methods to obtain yeast extract
1.




Autolyzed yeast extract
Consists of a concentration of yeast cells that are made to die and
break up.
This is followed by the breakdown of yeast’s proteins into simpler
compounds by the action of the yeast’s own endogenous digestive
enzymes.
The general method of making Autolyzed yeast extract on a
commercial scale is the addition of sodium chloride to a yeast
suspension. The hypertonic nature of the suspension leads to the
shriveling up of yeast cells, which triggers autolysis (self destruction)
of yeast.
The dying yeast cells are then heated to complete their breakdown,
after which the husk containing the yeast with thick cell walls is
separated. This removal of cell walls changes the texture and
concentrates the flavor.
2. Hydrolyzed yeast extract
 Differs from autolyzed yeast extract in the use of enzymes
that digest the yeast proteins.
 Hydrolyzed yeast extract is produced by the digestion of
yeast proteins by exogenous enzymes or acids.
YEASTS:
NUTRACEUTICALS
&
SUPPLEMENTS
BY: FARIA KHAN
COMMONLY USED YEASTS:
BREWER'S YEAST (SACCHAROMYCES CEREVISIAE)
RED YEAST RICE (MONASCUS PURPUREUS)
SACCHAROMYCES BOULARDII
NUTRACEUTICALS:
OSTEOARTHRITIS
ANTI CANCER
ANTI OXIDANT
BLOOD PRESSURE
IMMUNE RESPONSE
MOOD CONTROL
AIDS DIGESTION
HEART DISEASES
WHY WE NEED THEM?
portmanteau of the words
“nutrition” and
“pharmaceutical”
•Food
• Food products
provides health and
medical benefits
 prevention and
treatment of disease
BETA GLUCAN----- A SUPER FOOD
•anti cancer
•immuno modulator
•conquering infections
•cholestrol lowering
 “Beta glucan is a scientifically proven biological defense modifier (BDM)
that nutritionally potentiates and modulates the immune response.” It is
found in the cell walls of yeast and first identified in the 1960’s by Nicholas
DiLuzio, Ph.D.
 The cell walls of Saccharomyces cerevisiae yeast are an important source of
this polysaccharide.
 Beta-D-Glucan “has bioactive and medicinal properties, which include
immune stimulation, anti-inflammatory, anti-microbial, anti-infective, antiviral, anti-tumoral, cholesterol lowering, radioprotective and wound
healing.”
 “the 1,3-beta-D-glucans lentinan and schizophyllan have been used
clinically as adjuncts in cancer therapy.”
Freimund S, Sauter M, et al, A New Non-Degrading Isolation Process for 1,3-�-D-glucan of High Purity From Baker's Yeast
Saccharomyces cerevisia, Carbohydr Polymers, 2003;54:159-171.
PROS AND CONS OF USING YEAST IN
FOOD PRODUCTS
(Saima Siddique)
UG-3
INTRODUCTION
CANDIDA
ALBICANS
HEALTH BENEFITS OF YEAST IN FOOD
NUTRITIONAL YEAST
(18 amino acids)
(15 minerals)
Valuable and well known food supplement and healthy
impact on the body
The essential minerals and vitamins provided by nutritional yeast
include:
Managing stress level
Vitamin B complex
(Brewer’s yeast)
Biotin, pantothenic
acid, riboflavin,
pyridoxine, thiamine,
niacin and folic acid
Prevents pancreatic cancer
Break down carbohydrates ,fats and
proteins
Healthy functioning of digestive and
nervous system
Important for strong and healthy hair
Contributes to nail and growth and
strength.
Chromium
(GTF)
Dealing with diabetes and low blood
pressure.
Be helpful in reducing the amount of
fat
Knock down free radicals in body
Selenium
Improves the elasticity of skin
Development of nervous system in a
growing fetus
Folic Acid and Fibre
Rich source of fibre
Excellent alternate for dairy products
Plays important role in regulating blood sugar
Beneficial for people having digestive issues and
atherosclerosis
Beneficial for vegetarian and people on low cholesterol
diet
Cures conditions like eczema and dermatitis
NUTRITIONAL
YEAST
BREWER’S
YEAST
Deplete
vitamin B
in the body
Stomach
discomfort,
excess gas
and bloating
Increase the
effects of
diabetes
medications
Irritable
bowel
disease
Itching,
Urticaria,
and
Quincke's
edema
Allergic
reactions
Tyraminehypertensiv
e crisis