WATER IN

FOODS
Jasmine L. Carawana

Jasmine L. Carawana
 The water molecule; physical and chemical
A properties

TOPIC
B Forms of water in foods

OUTLINE
C Functions of water in food processing

D Effects of hardness in water in food processing

E Water treatment

F Water activity
 WATER
The most abundant substance on
earth, and depending on the Foods containing high water
local temperature, it exists in content are good breeding
solid, liquid, and vapor states. grounds for microbes, which
makes them highly susceptible
to microbial spoilage.
Scientific theories
proclaim that the genesis
of life on Earth would not The interaction of water with
have been possible without other components in a food
the presence of water system profoundly alters their
physical and chemical
properties, which impacts the
Food preservation techniques, such
sensorial properties and
as freezing and dehydration,
consumer acceptability of
involve the transformation of
foods.
liquid water into ice or its
removal as vapor, respectively
WATER CONTENT IN SOME FOODS
The water content of biological tissues varies from 50% to 90%. Since
fresh foods are derived mainly from plant and animal tissues, their water
content is also in the range of 50%–95% on a wet weight basis.

Food Water Content (%)

Tomato 95
Beer 90
Orange 87
Banana 75
Meat 65
White Bread 35
Honey 20
Rice 12
Milk Powder 4
A THE WATER MOLECULE: PHYSICAL AND
CHEMICAL PROPERTIES

Water molecules consist of two hydrogen

atoms and one oxygen atom that are held
together by a covalent bond.

Covalent bonds are formed between atoms

that share electrons
WATER MOLECULE

The atoms in a water’s

covalent bond do not share the
electrons equally.

The oxygen pulls on the

electrons more strongly than
the hydrogen atom.

This causes the water molecule

to be a polar molecule.
HYDROGEN BONDING BETWEEN WATER MOLECULE

A hydrogen bond is a relatively weak electrostatic

The intermolecular attraction attraction between a hydrogen atom in one molecule
among water molecules results (which is bonded to a highly electronegative atom like
in the formation of hydrogen oxygen, nitrogen, or fluorine) and an electronegative
bonds. atom in an adjacent molecule.
HYDROGEN BONDING IN ICE

Most liquids become more dense Each water molecule in ice forms
as you cool them. However, when four hydrogen bonds to its
water freezes, a large expansion neighbors, creating a regular
occurs. tetrahedral crystal lattice

Water “organizing”
with H bonds as it
freezes.
Forms hexagon shapes.
WATER AND ICE STRUCTURE
 GENERAL
PROPERTIES
OF WATER
PROPERTIES
OF WATER
STATES OF MATTER

Water exists naturally in three states: solid (ice),

liquid (water), and gas (water vapor or steam).

The transitions between these states occur at

specific temperatures and pressures:

Melting Point: 0°C (32°F) at standard

atmospheric pressure.

Boiling Point: 100°C (212°F) at standard

atmospheric pressure
PROPERTIES OF WATER
HIGH SPECIFIC HEAT CAPACITY

Water has an exceptionally high specific

heat capacity, meaning it can absorb or Specific heat capacity is the amount
release a large amount of heat energy with of heat needed to raise one gram of
only a small change in its own a material by one degree celsius (oC)
temperature.

This property is due to the extensive hydrogen

bonding network in liquid water. When heat is
added, much of the energy is used to break
these hydrogen bonds before the kinetic
energy of the molecules increases significantly.

PROPERTIES OF WATER
HIGH SPECIFIC HEAT CAPACITY

This characteristic is vital for regulating Earth's

climate, moderating temperatures in coastal
regions, and maintaining stable internal
temperatures in living organisms.
HIGH HEAT VAPORAZATION

Known as the enthalpy of vaporization, the heat of • Water has a high heat of vaporization
vaporization (∆Hvap) is defined by the amount of because hydrogen bonds form readily
enthalpy (heat energy) that is required to transform a between the oxygen of one molecule and
liquid substance into a gas or vapor. It is measured in the hydrogens of other molecules.
Joules per mole (J/mol), or sometimes in Calories (C).
• These bonds hold the molecules together.
To get water to vaporize, you must increase
the temperature to make the molecules
move faster.

• At a certain point, the molecules will begin

to break away from the liquid and vaporize.
 DENSITY ANOMALY

Unlike most substances, which become denser as they cool

and solidify, water reaches its maximum density at Density, mass of a
approximately 4°C (39.2°F). As it cools further to 0°C and unit volume of a
freezes, it expands, becoming less dense than liquid water. material substance.

The density of ice is less than water, allowing ice to

float on water. This phenomenon can be observed in
lakes on a freezing day. A thick layer of ice covers
the surface.

The ice traps the heat from escaping the lake,

preventing it from freezing. This way, fish and other
living organisms can survive underwater.
 EXCELLENT SOLVENT
PROPERTIES

Water is often referred to as the "universal solvent" due to its ability to dissolve a wide variety of
substances
“Like dissolves like”

It dissolves many polar

and ionic species. This • Polar solvents dissolve polar solutes.
property benefits living • Nonpolar solvents dissolve nonpolar
organisms since water solutes.
carries essential • Polar substances and nonpolar
substances generally remain
nutrients to different separate (think of salad dressing –
functional parts. forms a suspension when shaken)
COHESIVE PROPERTY AND
SURFACE TENSION

• Water molecules combine to form strong

hydrogen bonds, resulting in cohesive forces.
• Each molecule is pulled from all directions.
• On the surface, the molecules are only pulled
from the sides and the bottom, not from the
top.

Water forms a skin on the surface that can resist an

external force. This property of water is known as
surface tension. The value of surface tension is 0.072
J m².
ADHESIVE PROPERTY AND
CAPILLARY ACTION

• Water molecules can also stick to surfaces known as

adhesion.
• Water molecules adhering to the walls of a
container cause an upward force at the edges and
result in an upward meniscus.

Capillary action involves the movement of water

molecules. It occurs when adhesion to the walls is
stronger than the cohesion between the liquid
molecules
 Adhesion
The attraction of water molecules to another substance. Water
molecules stick to other things.

Ex.: Blood sticks to capillaries

Cohesion
The attraction between water molecules to each other
through hydrogen bonds (H). Water molecules stick to each
other.

Ex.: Surface tension holds spiders on water

B FORMS OF WATER
BOUND WATER FREE WATER

• It is incorporated into the chemical structure • It is the largest amount of water present in
of other components, such as proteins, foods.
lipids, and carbohydrates, as a monolayer/
multilayer bounded or capillary absorbed. • It is easily removed from the foods by drying,
centrifugation, and pressing.
• Bound water does not freeze and remains
unfrozen below the freezing point of water • It occurs by dispersing medium for salts, acids,
(usually at -20°C) sugars, etc.

• It is unavailable as a solvent for vitamins, • It can freeze at temperatures under freezing

acids, sugars, etc. point.

• It is resistant to drying and is not removed. • It triggers reactions since it is reactive.

• It can be found in food as a free (e.g. water in
fruits) or trapped form (e.g. starch gel).
FORMS OF WATER

Bound water is water that is unavailable as a solvent and is very difficult to

remove by simple drying or dehydration. It is water-bound to other food constituents and
remains unfrozen below 0°C.
Free water exists as a dispersing medium for the colloids and as a solvent for the
crystalloids present.
FORMS OF WATER
C WATER IN FOOD PRODUCTION

Processing Operations
Primary Production
1 3

Cleaning and Sanitation 2 4 Food Ingredient

PRIMARY PRODUCTION

The food and agriculture sectors are the largest

consumers of water.

The largest use of water is in primary food

production. In agriculture, water is
predominantly used for crop irrigation purposes.

In livestock farming, large volumes of water are

used for livestock watering along with
maintenance of general hygiene of the animals
and equipment.
PRIMARY PRODUCTION

The main source of food for the human population in

the world is agriculture, and this term also includes
livestock husbandry and forestry.

Food production from the livestock sector has

diversity such as meat (beef, pork, poultry, and
others), dairy products, and fish, aquatic, or seafood.

As the population keeps increasing, more food and

livestock feed have to be produced in the future, and
obviously, more water is required for this purpose.

Thus, agriculture has to claim larger quantities of

water to produce the food required to feed the world.
PRIMARY PRODUCTION
WATER FOOTPRINT
“The total volume of freshwater that is used to
produce the goods and services consumed by an
individual or community.”

The water footprint of any animal product is larger

than the water footprint of a wisely chosen crop
product with equivalent nutritional value.

Animals are secondary consumers in the food chain;

therefore, the calculation of the water footprint of
animals always adds up inherent increments of
primary consumers
CLEANING AND SANITATION

Water is a universal solvent.

When used in the context of food handling, it implies

the complete removal of food soil and associated
nonfood visible components using water and detergent
chemicals by appropriate methods or processes, under
recommended conditions.

The most important first step is flushing with water to

remove visible soil.

Cleaning also refers to the washing of equipment,

instruments, containers, plants, associated machinery,
and even the personnel who handle raw or processed
food.
 CLEANING AND SANITATION

SANITATION The statistical destruction

and removal of all living
organisms,
The reduction of
whereas disinfection refer
microorganisms to the level
s to inanimate objects and
that is considered safe from
the destruction of all
a public health viewpoint. It
vegetative cells (not
is essential to differentiate
spores).
and define certain
terminologies in the context
of food safety.
STERILIZATION
 CLEANING AND SANITATION

Water is used in sanitization.

It can be used alone or it can be

used along with some chemical
agent for effective sanitization.
Water is involved in approximately 95–
99% of the cleaning and sanitizing
operations of food production.
Water functions as a vehicle to
carry the detergent or the sanitizer
to the surface as well as remove
soil or contaminants from the food
surface.
 CLEANING AND SANITATION
THERMAL SANITIZATION
Sanitization that involves the use of hot water or steam for a specified temperature and contact time, is
called thermal sanitization. It is generally adequate for most purposes.

STEAM HOT WATER

➢ Has limited application. ➢ It involves immersion (of small parts,
➢ Disadvantages. knives, etc.), spray (such as
• Generally expensive as compared to dishwashers), or circulating systems.
alternatives.
• Temperature is difficult to regulate ➢ It is recommended that hot water
and also it is practically inconvenient immersion should be at 77°C (170°F) for
to monitor the contact temperature at least 30 seconds for manual
and time. operations.
• By-products of steam condensation
can complicate cleaning operations.
PROCESSING OPERATIONS

The major demand for water arises during

diverse food processing operations such as
the transport of products, dissolving
ingredients, treatment of products (e.g.,
alteration, separation), maintenance of
appropriate water content in the final product,
cooling processes, steam generation, and
abnormal incidents (e.g., fire protection).
 PROCESSING OPERATIONS

The reuse of water It is a very Under current legislation Even though clean
by recycling has essential way to in several countries, seawater is
become an conserve water, recycled water can be nonpotable, it is
increasingly vital reduce costs, and used in food processing commonly used in
component of food provide security for operations or as an processing
processing water supplies. ingredient of food, operations such as
operations. provided that it should be washing whole
of the same standards as fishery products and
drinking water. shellfish
FOOD INGREDIENT

Water is also used as a component of food or

an ingredient of the component food.

It is a very important safety concern when one

considers water as part of the food.

It acts as a medium through which food can be

preserved, stored, and consumed by humans.

Fruit juices, jams, jellies, pickles, soups, and

many more such consumed forms of food
products have water as an ingredient.
D WATER HARDNESS

Water hardness is the traditional measure of the capacity of water to react with soap.

1 3
What is Hard Water?
Fresh water supply that contains high
2
amounts of natural minerals like calcium
and magnesium.
Hard water requires considerably more
soap to produce lather and often makes a
noticeable deposit of precipitate (e.g.
insoluble metals, soaps, or salts) in
containers.
The principal natural sources of hardness in water are dissolved
polyvalent metallic ions from sedimentary rocks, seepage, and
runoff from soils.
Calcium and magnesium, the two principal ions, are present in
many sedimentary rocks, the most common being limestone and chalk.
1

2
 WATER 1 3
HARDNESS
SCALE 2
EFFECTS OF WATER HARDNESS
Exposure to HW has been suggested to be a risk factor that could exacerbate eczema. HW is
that increased usage in HW results in metal or soap salt residues on the skin (or clothes) that
are not easily rinsed off and that lead to contact irritation.
1 3
Drinking water in which both magnesium and sulfate are present at high concentrations (above
approximately 250 mg/l each) can have a laxative effect, although data suggest that consumers
adapt to these levels as exposures continue.
2
EFFECTS ON TASTE

Dissolved minerals contribute to the taste of drinking water

to varying degrees. Demineralized water tends to have a flat
taste, and producers of demineralized bottled or packaged
water often add some minerals for taste.
EFFECTS OF WATER HARDNESS

1 3

2
EFFECTS OF WATER HARDNESS

1 3

2
EFFECTS OF WATER HARDNESS

1 3

2
EFFECTS OF WATER HARDNESS

1 3

2
EFFECT OF WATER HARDNESS IN PROCESSING

01
01 Scale build up inside water pipes

02
02 Reduced water flow and increased stress on pipes

03
03 It can cause formation of film, scale, precipitates on equipment
surfaces

04 04 Spots on glasses and dishes

Affects the performance of cleaning chemicals. It can cost

05
money and economic losses to the processors. It may be in the
05
form of increased use of cleaning agents or increased cleaning
time.
HARD
WATER 1 3
VS.
SOFT 2
WATER
WATER SOFTENING PROCESS

1 3

2
E WATER TREATMENT

Water treatment involves using various functions (biological, chemical, physical, and
1 3
physicochemical) to reduce and or to eliminate toxins and contamination in water.

The objective of water treatment is to acquire water with the right properties for its
intended uses
WATER TREATMENT PROCESS

Coagulation Flocculation Sedimentation Filtration Disinfection

 1 3

WATER TREATMENT PROCESS

COAGULATION FLOCCULATION
➢ During coagulation, chemicals
with a positive charge are added 1 3
➢ Flocculation is the gentle mixing of the water to form
larger, heavier particles called flocs.
to the water.
➢ Often, water treatment plants will add additional
➢ The positive charge neutralizes chemicals during this step to help the flocs form.
the negative charge of dirt and
2
other dissolved particles in the
water.
➢ When this occurs, the particles
bind with the chemicals to form
slightly larger particles.
➢ Common chemicals used in this
step include specific types of
salts, aluminum, or iron.
 SEDIMENTATION
➢ Use to separate solids from the water.
➢ During sedimentation, flocs settle to the bottom of the water because they are heavier than water.

1
FILTRATION 3
➢ Once the flocs have settled to the bottom of the water, the During filtration, the clear
water passes through filters
from the water. 2
clear water on top is filtered to separate additional solids
with different pore sizes and
different materials (such as
sand, gravel, and charcoal).
These filters remove dissolved
particles and germs, such as
dust, chemicals, parasites,
bacteria, and viruses. Activated
carbon filters also remove any
bad odors.
 DISINFECTION
➢ Water treatment plants may add one or more chemical
disinfectants (such as chlorine, chloramine, or chlorine dioxide)
to kill any remaining parasites, bacteria, or viruses.

1
To help keep water safe as it travels to homes and
3
businesses, water treatment plants will make sure the water
has low levels of chemical disinfectant when it leaves the
treatment plant. This remaining disinfectant kills germs
living in the pipes between the water treatment plant and
your tap. 2
➢ In addition to or instead of adding chlorine, chloramine, or
chlorine dioxide, water treatment plants can also disinfect water
using ultraviolet (UV) light or ozone. UV light and ozone work
well to disinfect water in the treatment plant, but these
disinfection methods do not continue killing germs as water
travels through the pipes between the treatment plant and your
tap.
 1 3

2
 1 3

2
F WATER ACTIVITY

Water activity is a measure of free water in a

1 3
system available to support biological and
chemical reactions.

Water activity is the ratio of the partial

pressure of water in food to that of pure water
2 4
at a given temperature.
IMPORTANCE OF WATER ACTIVITY

Water activity (aw) is one of the most critical factors

in determining the quality and safety of foods.
1 3 the shelf life, safety, texture,
Water activity affects
flavor, and smell of foods.

While temperature, pH, and several other factors

2 4
can influence if and how fast organisms will grow in
a product, water activity may be the most important
factor in controlling spoilage.

Most bacteria, for example, do not grow at water

activities below 0.91, and most molds cease to grow
at water activities below 0.80.
IMPORTANCE OF WATER ACTIVITY

1 3
By measuring water activity, it is possible to predict which
microorganisms will and will not be potential sources of
spoilage.

2 4
Water activity--not water content--determines the lower
limit of available water for microbial growth.

In addition to influencing microbial spoilage, water activity

can play a significant role in determining the activity of
enzymes and vitamins in foods and can have a major
impact their color, taste, and aroma.
WATER ACTIVITY AND FOOD STABILITY

1 3

2 4
 WATER
1 3 ACTIVITY
AND FOOD
STABILITY
2 4
WATER ACTIVITY AND MOISTURE CONTENT

1 3

2 4
THANK YOU
Prepared by: Jasmine Carawana