Fermentation is the conversion of carbohydrates
to alcohols and carbon dioxide or organic acids
using yeasts, bacteria, or a combination thereof,
under anaerobic conditions.
Fermentation is employed in leavening of bread, in
preservation techniques to produce lactic acid in
sour foods such as sauerkraut, dry sausages, kimchi,
and yogurt; and in pickling of foods with vinegar.
It is generally used in producing Wine, Beer and Cider.
Leavening of Bread
Food is a basic necessity for life.
human life is unique in its capacity for gastronomic innovation, bread especially,
the most widely consumed food in the world, offers some of the most creative
variations. Through creative incorporation of a wide variety of edible
substances, advances in science and technology have allowed the production
and quality of bread to increase greatly over time.
Bread has many forms, is found in every culture and is still enjoyed daily
in most ancient simplicity.
Bread is highlighted by a number of developments made in technology,
adaptations through famines, the rise and fall of nations, kings and queens, the
Industrial Revolution, improved information access, religion and wars, all of which
have influenced bread as we know it today.
Timeline of bread development
The Neolithic Period
Panem et Circenses
The Middle Ages
The Renaissance to the Industrial Revolution
Discovery of Grains
Between 10,000 BC-4000 BC, a shift took place in food production
and consumption. Human civilizations transitioned from hunter
gatherers to fixed, agrarian based communities. Grains began to be
harvested for food. Boiling grains allowed for easier digestion and
access to more nutrition, much like porridge today.
As technology developed, so did the process for preparing grains.
Porridge was cooked on stone slabs, making crude flat breads that
were less prone to spoilage and more easily transported. These
advances in bread making laid the groundwork for Egyptian and
Between 5500 BC and 300 AD, Egyptians and Greeks experimented with different
ingredients and techniques. Egyptian flatbreads were made from wheat, barley or
spelt flour, salt and water, kneaded with hands or feet and baked on stone slabs.
During this time, the diversity of ingredients available allowed human creativity to
supercharge the artistic element of bread making. Advances in understanding of
fermentation led to the important development of leavened breads. Leavened
breads were made from about 1500 BC onward.
Egyptian flatbreads are still made today
CLASSIC ANTIQUITY ~ Greek &
Fermentation occurs when yeast and bacteria inside the dough convert
carbohydrates to carbon dioxide causing gas bubbles to form, which has a
leavening effect on dough. This process is very similar to wine, beer and
sour kraut and causes a strong aromatic pleasing sensation. The gas
bubbles expand inside the dough making the dough appear larger, this is
called leavening. There are two theories for the origins of leavened bread
dating back to Antiquity:
• Egyptian beer was added to in lieu of water, thus introducing yeast
into the dough.
• A piece of dough was forgotten, leavened by ambient yeast and later
Connection was made between the fermentation of beer and
fermentation of dough. This development ultimately gave Egyptian bread
a new dimension with new possibilities. Greeks used wine in the bread
making process, whereas Gauls and Iberians used the foam found atop ale
for dough fermentation
PANEM ET CIRCENSES
For Egyptians and Greeks, it was clear that order in the streets was easier to maintain
if the food needs of the people were met. There was an ancient Egyptian saying; i.e.
"He whose belly is empty complains loudest!". Therefore, grain production was
given the highest priority. Bread was also an important component of religious
celebrations. Ramses III, for example, sacrificed 200,000 loaves of bread to the gods
The importance of bread to Greeks and Egyptians was passed on to the Romans
who created guild like organizations to ensure quality bread production and
innovation. Roman rulers would say "Panem et Circenses!", which means, "Bread
and Circuses!", in reference to the superficial means of appeasement they would
provide the people to gain support.
THE MIDDLE AGES
The Middle Ages were a time of great fluctuation in grain availability, production
• famine, bad weather and disease were some of hallmarks of this period
which led to a decline in the availability and demand for bread.
• By the end of this era, growing urbanization, the creation of baker's guilds
and technological advances in ovens contributed to the greater demand for
Agriculture was reintroduced by the Catholic Church around 1000 AD as bread
was needed for the important sacrament of communion and clergy were
learning from agricultural texts written by their Greco-Roman ancestors.
The first bakers guild formed in France around 1200AD. It was called the
Tameliers, which means flour sifters. To become a member of the Tameliers, one
had to go through a four year apprenticeship, pass a number of tests and be
granted the right to bake from the king. Baking was viewed as an honourable
Bakers in guilds enjoyed many benefits. For example, bakers who supplied
bread to hospitals were, in return, given free medical care. Bread in the
13th century mostly contained wheat and the richer you were, the whiter
your bread. Poor people ate whole wheat bread containing lots of bran and
wheat germ. Its interesting to note that it has been scientifically proven that
whole grain bread containing bran and the germ is better for you than white
bread made solely from the starchy white endosperm of the wheat berry.
With the production of bread well established, bakers began to explore
specialty items. Sweet breads, braids and pastries quickly became popular
all over Europe. Bakers began to enrich doughs with eggs, dairy, honey and
sometimes sugar brought back from the Crusades.
By the end of the Middle Ages, laws concerning the production of bread
were being written by royalty and guilds were clearly developed, respected
Renaissance into the Industrial Revolution
Royalty maintained its grip on bread making throughout the Renaissance.
Laws for the production and sale of flour and bread reached new heights
by 1600, primarily due to the demand for bread and the availability of
grain during FRENCH REVOLUTION.
Bakers put a distinctive trademark on their loaves, kept weights and scales
in their shops under penalty of having their licenses removed.”
During the 16th and 17th centuries danger of famine was a constant
reality. Demand for bread grew and so did the price. People flocked to
food-stable cities and Kings and Queens were relied upon to maintain the
food equilibrium. If they failed, uprising ensued.
With the advances in science and technology in the Industrial Age, chemical leavening agents
such as ammonia, potassium bicarbonate, sodium bicarbonate and manufactured yeast were
used more commonly than old perpetuated bacterial cultures.
By the mid to late 1800’s, technological developments in many areas set the stage for the mass
production of the twentieth century.
• The first modern mill was constructed in 1830 adapting to hydraulic power in 1875.
These mills were located by rivers and could produce massive amounts of flour.
• Dough mixers were invented in 1850 and became standard use in bakeries fifty years later.
• Ovens were being built regularly using coal, wood and oil to fire them.
Big commercial bakeries first began to produce large quantities of bread for mass
consumption around 1900. After WWI, a study through Stanford University found that 610 percent of bread production went unsold, this translated into over half a million barrels
of flour were being wasted every year.
Flour was bleached and additives were introduced to lengthen shelf life and increase
France passed Bread Laws of 1993, protecting the small bakeries, traditions and
diversity of artisan bread.
The stages of bread making are the same for when bread is made by hand, assisted
with a mixer or in a bread machine, using Bread Mix or when making from ‘scratch’.
Bread machines and mixers make some of the more physically demanding steps easy.
• There are many types of bread.
• Bread can be made more interesting by adding different ingredients.
• Bread is a good source of carbohydrates, protein, B-group vitamins and
the minerals calcium and iron.
• Wholemeal bread is a very good source of NSP (dietary fibre).
All Purpose flour:
• Has a high GLUTEN content. Gluten is a protein in the flour; when mixed with water, it
forms an elastic and stretchy texture.
• This elasticity allows dough containing yeast to stretch and hold carbon dioxide gas in
small pockets. This creates a light and open texture.
• Gluten sets when cooked at high temperatures and forms the framework and shape of
• Wholemeal flour can also be used. Use half wholemeal flour to half white flour for
• Yeast is a biological raising agent.
• Yeast is a raising agent used in bread making.
• Produces carbon dioxide gas, which makes the bread rise. This is called
• Yeast is a single-cell plant fungus that needs food, moisture, warmth and time in
order to grow and ferment.
Types of yeast:
• Fresh yeast is a firm, moist, cream-coloured block available from bakeries.
• Dried yeast comes in small granules that are first reconstituted with warm
water and sugar.
• Powdered (or ‘easy-blend’ or ‘fast-action’) dried yeast is sprinkled straight into
a bowl of flour.
• Historically, the starter for breads consists of the natural biota of baker’s barm.
• The barm generally contains a mixture of yeasts and lactic acid bacteria.
• In the case of San Francisco sourdough bread, the yeast has been identified as
Saccharomyces exiguus and the responsible bacteria are Lactobacillus
sanfranciscensis, L. fermentum, L. fructivorans, some L. brevis strains, and L. pontis.
• The key bacterium is L. sanfranciscensis, and it ferments maltose rather than
glucose and requires fresh yeast extractives and unsaturated fatty acids.
• The souring is caused by acids produced by these bacteria, and the yeast is
responsible for the leavening action, although some CO2 is produced by the
• The pH of these sourdoughs ranges from 3.8 to 4.5.
• Both acetic and lactic acids are produced, with the former accounting for 20–30%
of the total acidity.
• Binds the dry ingredients together and helps in the development of gluten.
• The liquid should be lukewarm (25°C to 35°C) to help the yeast fermentation.
• If the liquid is too hot the yeast will be destroyed, if too cold the action of the yeast
is slowed down.
• Adds flavour
• Controls the action of the yeast
• Strengthens the gluten
• Enhances colour and flavour
• Increases shelf-life, prevents the bread going stale
• Small amounts aid fermentation
• Can be added to sweet or rich yeast doughs.
Mixing and kneading:
• Flour, salt and fat are mixed with the yeast and water.
• Flexible dough is formed.
• Kneaded to stretch the dough and develop the gluten and form an elastic
• The dough is left to stand to rise.
• This is called proving.
• The yeast produces carbon dioxide gas, which causes the dough to rise.
• To create an evenly textured bread the dough is kneaded to release some of
• It is left to rise again
• The gluten should now be thoroughly distributed.
• The dough is shaped and left to prove again
• The heat sets the gluten and stops the yeast working.
• The heat sets the shape.
Ropiness is bacterial spoilage of bread that initially occurs as an unpleasant fruity odour,
followed by enzymatic degradation of the crumb that becomes soft and sticky because of
the production of extracellular slimy polysaccharides.
The species involved in this type of spoilage of bread are primarily Bacillus subtilis and
occasionally Bacillus licheniformis, Bacillus pumilus, and Bacillus cereus, even though
some rope-producing Bacillus isolates are often not identified at the species level
Spores of B. subtilis have been isolated from ropy bread, raw materials, and bakery
environments and also from additives, including yeast, bread improvers, and gluten.
B. subtilis spores are heat resistant and can survive during baking in the core of the
crumb, where the maximum temperature is 97 to 101°C for a few minutes.
Ropiness occurs particularly when warm (25 to 30°C) and humid (water activity, ≥0.95)
environmental conditions allow germination of Bacillus spores.
The water activity, pH, and temperature during storage may also play important roles in
spore germination and growth of vegetative cells of Bacillus spp.
Moreover, rope-causing strains are also characterized by faster development and
enhanced protease and amylase production during growth in the bread crumb
• Cheese is a food derived from milk that is produced in a wide range of flavours,
textures, and forms by coagulation of the milk protein casein.
• It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or
• During production, the milk is usually acidified, and adding the enzyme rennet
causes coagulation. The solids are separated and pressed into final form.
• Some cheeses have moulds on the rind or throughout.
• Most cheeses melt at cooking temperature.
• Hundreds of types of cheese from various countries are produced.
• Their styles, textures and flavours depend on the origin of the milk (including
the animal's diet), whether they have been pasteurized, the butterfat content,
the bacteria and mold, the processing, and aging.
• Herbs, spices, or wood smoke may be used as flavouring agents.
• For a few cheeses, the milk is curdled by adding acids such as vinegar or lemon
• Most cheeses are acidified to a lesser degree by bacteria, which turn milk sugars
into lactic acid, then the addition of rennet completes the curdling.
• Vegetarian alternatives to rennet are available; most are produced by
fermentation of the fungus Mucor miehei,
Cheese is an ancient food whose origins predate recorded history. There is
no conclusive evidence indicating where cheese making originated, either
in Europe, Central Asia or the Middle East, but the practice had spread
within Europe prior to Roman times and, according to Pliny the Elder, had
become a sophisticated enterprise by the time the Roman Empire came
Early archaeological evidence of Egyptian cheese has been found in
Egyptian tomb murals, dating to about 2000 BCE. The earliest cheeses
were likely to have been quite sour and salty, similar in texture to rustic
cottage cheese or feta, a crumbly, flavourful Greek cheese.
Factory-made cheese overtook traditional cheese making in the World
War II era, and factories have been the source of most cheese in
America and Europe ever since. Today, Americans buy more processed
cheese than "real", factory-made or not.
Types of Cheese
Every cheese has a texture that defines it. This texture refers to the degree
of hardness, or to put it another way, how much moisture remains in the
cheese when it is ready to eat. The method of manufacturing the cheese
and the length of time it is aged will determine its texture and its degree
of firmness. Cheeses which share some basic characteristics can be
grouped together according to the following types of cheese:
2. Soft-ripened or “bloomy rind” cheese
8. Double and triple crème
9. Pasta Filata (meaning spun paste)
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