Food technology

2. Fermentation of pickle
 Pickling is the process of preserving food by anaerobic fermentation
in brine or vinegar. The resulting food is called a pickle. This
procedure gives the food a salty or sour taste.
 The fermentation of cucumbers is very similar to the sauerkraut
fermentation; only brine (salt solution) is used instead of dry
salt. The washed cucumbers are placed in large tanks and
chlorinated brine with 15 to 20% sodium chloride is added.
 The cucumbers are submerged in brine ensuring that none

3. float on the surface, prevent spoilage of pickle.
 Another distinguishing characteristic is a pH less than 4.6, which is
sufficient to kill most bacteria. Pickling can preserve perishable foods
for months. Antimicrobial herbs and spices, such as mustard seed,
garlic, cinnamon or cloves, are often added.
 If the food contains sufficient moisture, a pickling brine may be
produced simply by adding dry salt.
 Natural fermentation at room temperature, by lactic acid
bacteria, produces the required acidity. Other pickles are made
by placing vegetables in vinegar. Unlike the canning process,
pickling (which includes fermentation) does not require that the
food be completely sterile before it is sealed.

4.  The acidity or salinity of the solution, the temperature of fermentation,
and the exclusion of oxygen determine which microorganisms
dominate, and determine the flavor of the end product.
 When both salt concentration and temperature are low,
Leuconostoc mesenteroides dominates, producing a mix of acids,
alcohol, and aroma compounds. At higher temperatures
Lactobacillus plantarum dominates, which produces primarily
lactic acid. Many pickles start with
Leuconostoc, and change to Lactobacillus
with higher acidity.

5. • Sauerkraut:
• The words sauerkraut are germen terms for sour cabbage. Sauerkraut is
a product of natural lactic acid fermentation of fresh cabbage in the
prescence of a small amount of salt involving lactic acid bacteria,
leuconostoc mesenteroides and lactobacillus plantarum.
• Sauerkraut is rich in vitamin c and has a mild laxative action due to
dextran content of the product.
Nutritional value per (100 g)(3.5 oZ)
Energy - 78KJ (19 Kcal)
carbohydrate - 4.3 g
sugar - 1.8 g
dietary fibre - 2.9 g

6. Fat - 0.14 g
Water - 92 g
Vitamin B - 0.13 mg (10%)
Vitamin C - 15 mg (18%)
Iron - 1.5 mg (12%)
Sodium - 661 mg (44%)
 It has a long shelf-life and a distinctive sour flavor, both of which result
from the lactic acid that forms when the bacteria ferment the sugars in
the cabbage. Sauerkraut is also used as a condiment upon various foods,
such as meat dishes and hot dogs.

7. Bread:
• Leavened breads are made by adding baker’s yeast to dough made
from flour, water and salts. Yeast ferment sugar in dough to alcohol
and carbon dioxide.
• A pre-ferment and a longer fermentation in the bread-making process
have several benefits: there is more time for yeast, enzyme and, if
sourdough, bacterial actions on the starch and proteins in the dough;
this in turn improves the keeping time of the baked bread, and it
creates greater complexities of flavor.
• Though pre-ferments have declined in popularity as direct additions of
yeast in bread recipes have streamlined the process on a commercial
level, pre-ferments of various forms are widely used in artisanal bread
recipes and formulas.

8. .
• Most of the bakery foods consumed throughout the world are bread
and rolls made from yeast-leavened doughs.
Bread making:

9.  Vinegar:
 Vinegar is a liquid consisting mainly of acetic acid (CH3COOH) and
water. The acetic acid is produced by the fermentation of ethanol by
acetic acid bacteria.
 Vinegar is now mainly used as a cooking ingredient, but historically, as
the most easily available mild acid, it had a great variety of industrial,
medical, and domestic uses, some of which (such as a general
household cleanser) are still promoted today.
 Commercial vinegar is produced either by fast or slow fermentation
processes. . In general, slow methods are used with traditional
vinegars, and fermentation proceeds slowly over the course of
months or a year.

10.  The longer fermentation period allows for the accumulation of a
nontoxic slime composed of acetic acid bacteria.
 Fast methods add mother of vinegar (i.e., bacterial culture) to the
source liquid before adding air using a venturi pump system or a
turbine to promote oxygenation to obtain the fastest fermentation.
 In fast production processes, vinegar may be produced in a period
ranging from 20 hours to three days.

11.  Vinegar production process:

12. Uses
• Vinegar is commonly used in food preparation, in particular in pickling
processes, vinaigrettes, and other salad dressings
Blood glucose control and diabetic management
• Prior to hypoglycemic agents, diabetics used vinegar teas to control
their symptoms. Small amounts of vinegar (approximately 25g of
domestic vinegar) added to food, or taken along with a meal, have been
shown by a number of medical trials to reduce the glycemic index of
carbohydrate food for people with and without diabetes.
• This also has been expressed as lower glycemic index ratings in the
region of 30%.

13. Diet control
• Multiple trials indicate that taking vinegar with food increases satiety
(the feeling of fullness) and, so, reduces the amount of food consumed.
Daily intake of 15 mL of vinegar (750 mg acetic acid) might be useful in
the prevention of metabolic syndrome by reducing obesity.
Idli:
• Idly, is a traditional breakfast in south Indian households. Idli is savory
cake of South India that is most popular throughout the southern part of
India including Karnataka, Tamil Nadu, Pondicherry, Kerala, Andhra
Pradesh and neighbouring countries like Sri Lanka.
• The cakes are usually two to three inches in diameter and are
made by steaming a batter consisting of fermented black lentils
(de-husked) and rice.

14.  The fermentation process breaks down the starches so that they are
more readily metabolized by the body.
Idli fermentation process:

15.  Bacteria identified as part of microflora responsible for the
production of good idli include, leuconostoc mesenteroides,
lactobacillus fermentum, lactobacillus delbrueckii, lactobacillus
lactis.
Single cell protein:
 The dried cells of microorganisms used as food or feed are
collectively known as “single cell protein” since the ancient times
number of microorganisms have been used as a part of diet.
 The protein stroage, microorganisms offer many possibilities for
protein production. they can be use used as to totally or
partially the valuable amount of conventional vegetable

16. and animal protein feed.
 Since the spirullina is a rich source of protein (60-70%),
vitamins, aminoacids, minerals, crudefibres etc.. it is used as a
supplented food in developing countries.
 Mass multiplication of spirullina offers several advantages over
other single cell protein.
 Beings a filamentous alage, spirullina can be harvested by simple
and less expensive method.
 Filament of spiullina float on water surface due to the prescence
of gas vacuoles, hence harvesting is easy.
 There is a least chance of contamination in growth tanks of
spirullina as it grows at high pH 8-11.

17.  Heat drying is sufficient for spirullina as it has thin cell wall.
 Spirullina is highly digestive (85-95%)due to thin wall and low
nucleic acid content (4%). It contains high percentage of
proteins (62-72%) vitamins, aminoacids.
Single-cell protein (SCP) typically refers to sources of mixed
protein extracted from pure or mixed cultures of algae, yeasts,
fungi or bacteria (grown on agricultural wastes) used as a
substitute for protein-rich foods, in human and animal feeds.
Production Process
 Single-cell proteins develop when microbes ferment waste
materials (including wood, straw, cannery, and

18. food-processing wastes, residues from alcohol production,
hydrocarbons, or human and animal excreta).
 The problem with extracting single-cell proteins from the wastes is the
dilution and cost. They are found in very low concentrations, usually
less than 5%. Engineers have developed ways to increase the
concentrations including centrifugation, flotation, precipitation,
coagulation, and filtration, or the use of semi-permeable membranes.
 The single-cell protein must be dehydrated to approximately 10%
moisture content and/or acidified to aid in storage and prevent
spoilage. The methods to increase the concentrations to adequate
levels and the de-watering process require equipment that is expensive
and not always suitable for small-scale operations.

19.  It is economically prudent to feed the product locally and soon
after it is produced.
 Single Cell Protein that can be used in feed for animals.
Examples
 Microbes employed include yeasts (Saccharomyces cerevisiae,
Pichia pastoris, Candida utilis=Torulopsis and Geotrichum
candidum (=Oidium lactis)), other fungi (Aspergillus oryzae,
Fusarium venenatum, Sclerotium rolfsii, Polyporus and
Trichoderma), bacteria (Rhodopseudomonas capsulata). and
algae (Chlorella and Spirulina). Typical yields of 43 to 56%, with
protein contents of 44% to 60%.

20. • The fungus Scytalidium acidophilum grows at below pH 1, offering
advantages of:
• low-cost aseptic conditions
• avoiding over 100-fold dilution of the acidic hydrolysates to pH values
needed for other microbes
• after the biomass is harvested, the acids can be reused.
Product Safety and Quality
• Some contaminants can produce mycotoxins. Some bacterial SCP have
amino acid profiles different from animal proteins. Yeast and fungal
proteins tend to be deficient in methionine.
• Microbial biomass has a high nucleic acid content, and levels must be
limited in the diets of monogastric animals to <50 g per day. Ingestion

21.  of purine compounds arising from RNA breakdown leads to
increased plasma levels of uric acid, which can cause gout and
kidney stones.
 Uric acid can be converted to allantoin, which is excreted in
urine. Nucleic acid removal is not necessary from animal feeds
but is from human foods.
 A temperature hold at 64°C inactivates fungal proteases and
allows RNases to hydrolyse RNA with release of nucleotides
from cell to culture broth.
Advantages of Production
 Large-scale production of microbial biomass has many
advantages over the traditional methods for producing proteins

22. for food or feed.
 Microorganisms have a high rate of multiplication and, hence, rapid
succession of generations (algae: 2–6 hours, yeast: 1–3 hours,
bacteria: 0.5–2 hours)
 They can be easily genetically modified for varying the amino acid
composition.
 A very high protein content 43–85% in the dry mass.
 They can utilize a broad spectrum of raw materials as carbon
sources, which include even waste products. Thus, they help in the
removal of pollutants also.
 Strains with high yield and good composition can be selected or
produce relatively easily.

23.  Microbial biomass production occurs in continuous cultures and
the quality is consistent, since the growth is independent of
seasonal and climatic variations.
 Land requirements is low and is ecologically beneficial.
 A high solar-energy-conversion efficiency per unit area.
 Solar energy conversion efficiency can be maximized and yield
can be enhanced by easy regulation of physical and nutritional
factors.
 Algal culture can be done in space that is normally unused and
so there is no need to compete for land.

24. Nutritional value of spirullina for human consumption:
• Since spirullina is a rich source of protein (60-72%), vitamins,
aminoacids, minerals, crude fibre. Spirullina has a net protein
utilization of 56.6% spirullina contain 8 essential aminoacids.
spirullina tablet
Spirullina as health food:
• Spirullina is a very popular health food.
It is the part of the diet of the US olymptic
team. jaggersbtakes spirullina tablets for
instant energy. Since it provides all the essential nutrients without
excess calories and fats, it is taken by those who want to control obesity.

25. Therapeutic and natural medicine:
Spirullina possesses many medicinal properties. It has been
recommended by medicinal experts for reducing body weight,
chloestrol and for better health.
Cosmetics:
Spirullina contains high quality of proteins and vitamins A and B.
thease play a key role in maintaining healthy hair. Phycocyanin
pigment has helped in formulating biolipstics and herbalface
cream in japan. spirullina

26. Single cell protein process

27. Milk :
• Milk is an excellent medium for microbial growth and when stored
at ambient temperature bacteria and other pathogens soon
proliferate.
• The Centers for Disease Control (CDC) says improperly handled
raw milk is responsible for nearly three times more
hospitalizations than any other foodborne disease outbreak,
making it one of the world's most dangerous food products.
• Diseases pasteurization can prevent include tuberculosis,
brucellosis, diphtheria, scarlet fever, and Q-fever; it also kills the
harmful bacteria Salmonella, Listeria, Yersinia, Campylobacter,
Staphylococcus aureus, and Escherichia coli among others.

28. • Pasteurization is the main reason for milk's extended shelf life. High-
temperature, short-time (HTST) pasteurized milk typically has a
refrigerated shelf life of two to three weeks, whereas ultra-
pasteurized milk can last much longer, sometimes two to three
months.
• When ultra-heat treatment (UHT) is combined with sterile handling
and container technology (such as aseptic packaging), it can even be
stored unrefrigerated for 6 to 9 months.
Raw milk:
Raw milk is milk that has not been pasteurized or homogenized. While
proponents claim there are benefits to raw milk that is made without
pasteurization and homogenization, the medical community warns of
the dangers of unpasteurized milk. Availability and regulation of raw

29. vary from region to region.
• Pasteurization is widely used to prevent infected milk from entering
the food supply. The recognition of many potentially deadly
pathogens, such as E. coli , Listeria, and Salmonella, and their
presence in milk products has led to the continuation of
pasteurization.
• The Department of Health and Human Services, Center for Disease
Control and Prevention, and other health agencies of the United
States strongly recommend that the public do not consume raw milk
or raw milk products.
• Young children, the elderly, people with weakened immune systems,
and pregnant women are particularly susceptible to infections

30. raw milk.
• Re-pasteurization occurs when pasteurized milk from the US
mainland is transported by sea to Hawaii, and then pasteurized
again.
• Recent advances in the analysis of milk-borne diseases have enabled
scientists to track the DNA of the infectious bacteria to the cows on
the farms that supplied the raw milk.
Spoilage in milk:
• Spoilage is a term used to describe the deterioration of foods
texture, colour, odour or flavour to the unsustible for human
conssumption.
• Microbial spoilage of food aften involves the degradation of protein,
carbohydrates and fats by the microbes or their enzymes.

31. • Few specices of Bacillus, Clostridium, Corynebactrium, Arthrobacter,
Lactobacillus, Microbacterium, Micrococcus and Streptococcus can
survive pasterization and can grow at refrigeration temperatures which
can cause spoilage problems
milk products:
• Important dairy product are yoghurt, cheese, kefir, kumiss, butter,
butter milk etc..
Yoghurt:
• It is a fermented milk product, mostly available europe and north
america.
• The name is derived from furkish word “jaghurt” it’s obtained from
cow’s milk, sheep’s milk.

32. • The two important organisms involved in production of yoghurt are
Strep. Thermophilus – faster and high acid
Lacto. Bulgaricans - adds flavour and aroma
• The final products of yoghurt has curd tastes and flavours due to
lactic acid and volatile product
• Worldwide, cow's milk, the protein of which mainly comprises
casein, is most commonly used to make yogurt, but milk from water
buffalo, goats, ewes, mares, camels, and yaks is also used in various
parts of the world.
• Alternatively, soy milk, nut milks such as almond milk, and coconut
milk can also be used.

33. • Dairy yogurt is produced using a culture of Lactobacillus delbrueckii
subsp. bulgaricus and Streptococcus thermophilus bacteria. In
• addition, other lactobacilli and bifidobacteria are also sometimes
added during or after culturing yogurt.
• Some countries require yogurt to contain a certain amount of colony-
forming units of microorganisms

34. Yoghurt production process

35. Fermentation:
• Takes place about 4th day of addition of starter culture. Starter bacteria
ferment lactose to lactic acid.
• The lactic acid solubilises and denature whey protein and solubilise ca
and po4.
• Streptococcus inturn produce fermentation acid, pyruvate that flavours
the growth of lactobacillus to produce purines in it.
Yield:
• Yoghurt with clean flavour 2-3 fat, slightly sour acid in 0.9 % can go up
to 1.1%.

36. Cheese
• Cheese is a food derived from milk that is produced in a wide range of
flavors, 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 sheep.
• 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
molds 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 flavors depend on the origin of the milk (including
the animal's diet), whether they have been pasteurized,

37. the butterfat content, the bacteria and mold, the processing, and aging.
Herbs, spices, or wood smoke may be used as flavoring agents.
• The yellow to red color of many cheeses, such as Red Leicester, is
produced by adding annatto.
• Other ingredients may be added to some cheeses, such as black
peppers, garlic, chives or cranberries.
• For a few cheeses, the milk is curdled by adding acids such as vinegar
or lemon juice.
• 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, but others
have been extracted from various species of the Cynara thistle family.

38. Cheese production process

39. classification of cheeses
• Cheeses are normally classified according to firmness, which varies
with the degree of moisture.
• The moisture content of firm cheeses may be as low as 30%, while that
of soft or fresh cheeses may be as high as 80%. The most common
designations include fresh (or unripened) cheeses, soft ripened
cheeses, firm or semi-firm cheeses, blue-veined, processed and goat’s-
milk cheeses.
Fresh cheeses
• Fresh or unripened cheeses are coagulated under the action of lactic
acid fermentation in the milk instead of adding rennet. While they
are drained after formation of the curd, they are neither ripened nor
fermented.

40. • This category includes cottage cheese, ricotta, mascarpone, cream
cheese and quark. Fresh cheeses are mainly used in baking and
desserts, plain or flavored with vegetables, fruits, herbs or spices.
Soft cheeses
• Soft cheeses are ripened for a relatively short period of time before
being drained and turned into molds without being pressed or
cooked.
• They have a moisture content of 50% to 60% and their fat content
represents 20% to 26% of the cheese’s weight.
• They develop a soft rind that can be more or less satiny and are usually
eaten with bread, since they tend to lose a lot of flavor when heated.

41. Firm and semi-firm cheeses
• Semi-firm cheeses are uncooked pressed cheeses that are dense and
usually pale yellow in color. They include Cheddar, Cantal,
Reblochon, Edam, Gouda and Monterey Jack.
• Firm cheeses are cheeses that have been cooked and pressed. The
curd is heated for an hour in order to make it more concentrated,
which, upon pressing, produces a more compact cheese.
• Their texture is usually firm, although some hard cheeses, like
Parmesan and Romano, may have a rather granular texture.
Blue-veined cheeses
Blue-veined (or blue) cheeses are neither cooked nor pressed; the curd is
inoculated with a species of blue-green mold, which is injected into the
cheese by means of long needles.

42. Cheese making
• Coagulation (“curdling”) is the curd-forming stage, when the casein
(the protein contained in the milk) coagulates in response to bacteria
or rennet.
• Drainage consists in removing the water (the whey or lactoserum)
from the curd and making it firmer.
• The amount of whey retained in the curd after draining will determine
the firmness and texture of the cheese.
• It is during the draining stage that the curd is shaped in a mold.
• Salting acts as an antiseptic, slows down the development of
microorganisms, improves the storage life of the cheese and
speeds up the drying process and the formation of a rind.

43. • Ripening (or maturing) is the period during which the inside of the
cheese is transformed through the biochemical action of the
bacterial flora contained in the cheese.
• This is the crucial stage in which the consistency, aroma, flavor and,
if desired, the rind of the cheese develop (fresh curd cheeses and
process cheeses are not ripened).
• Ripening takes place under temperature and humidity conditions
that vary according to the type of cheese.
• The longer the ripening process, the less moisture the cheese retains,
and the firmer and stronger-tasting the cheese .

44. Butter
• Butter is a dairy product that consists of butterfat, milk proteins, and
water. It's made by churning fresh or fermented cream or milk. It is
used as a spread and a condiment—and in cooking, such as baking,
sauce making, and pan frying.
• Commonly made from cows' milk, butter can also be manufactured
from the milk of other mammals, including sheep, goats, buffalo, and
yaks. Producers sometimes add Salt, flavorings, or preservatives.
• Rendering butter produces clarified butter or ghee, which is almost
entirely butterfat.

45. Butter production process