ERT 426 Food Engineering
Semester 1 Academic Session 2014/15
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Subtopics
1. Food ingredients plants.
2. Properties of foods.
3. Food Additives
4. Food safety in Malaysia
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1. Food ingredients plants
 Food ingredients plants utilize agricultural
and natural raw materials to separate and
recover valuable food components, such as
wheat flour, sugar, edible oils, pectin, protein,
and salt, which are used in the manufacture of
several food products.
 Wheat flour and other cereal flours can be
considered as food ingredients, which are
used in large quantities in the baking and
other food industries.
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Food ingredients plants
 Various other food ingredients, used in
smaller quantities, are produced by the
Chemical Process Industries, examples:
 flavors and gums,
 coloring materials,
 sweeteners,
 antioxidants,
 preservatives,
 vitamins,
 nutritive minerals, and
 special food chemicals.
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Food ingredients plants
 The raw materials of the natural food
ingredients are bulk agricultural
products of relatively low cost, such as
cereal grains (wheat, corn), sugar beets
or sugar cane, and soybeans.
 Some food ingredients are produced
from byproducts of food preservation or
food manufacturing plants, e.g., pectin
from citrus or apple peels, and protein
from cheese whey.
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Food ingredients plants
 Table 1: Food Ingredients Plants.
Food Ingredient
Category
Processing Plant
Food flours
Wheat, Other grain, Soya
Sugars / starches Beet sugar, cane sugar,
Starches, modified
starches
Corn syrups
Food biopolymers Pectin, Cellulose, Gelatin
Whey protein, Soy protein
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Food ingredients plants
 Table 1: Food Ingredients Plants.
Food Ingredient
Category
Processing Plant
Vegetable oils
Soybean oil, Corn oil,
Rapeseed oil, Olive oil
Plant extracts
Flavors, colors,
Hydrocolloids Gums,
Phytonutrients
Food chemicals
Vitamins, Amino acids,
and biochemicals Antioxidants, Acidulants
Preservatives, Enzymes
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2. Properties of foods
 Foods are composed of chemicals, and for
food manufacturers it is the chemical
composition that determines all aspects of
their products:
 from the suitability of raw materials for use
in particular products and processes, to the
sensory characteristics and nutritional
value of the processed foods, as well as
wider issues such as food safety and
quality assurance, traceability, product
development and labelling.
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Properties of foods
 Chemical components of foods are
divided into:
1. the macromolecular components
(carbohydrates, lipids, proteins),
2. water, which is a major component of
many foods,
3. the micro-components (vitamins,
minerals, natural colourants, flavours,
toxins and additives).
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3. Food Additives
 Food additives are artificial or natural
chemicals, purposely added to food
(directly or indirectly) which affecting
the characteristics of the food
 e.g: to preserve flavor or enhance its
taste and appearance.
Food Additives
• Emulsifier
• Nutrient supplements
• Stabilizers/Thickeners
• Antioxidant
• Acidulants
• Enzymes
• Flavoring agents
• Coloring agents
• Antibrowning agents
• Dough conditioners
• Humectants
• Curing agents
• Sweeteners
3.1 Emulsifiers
 Chemicals that reduce the surface tension in
the surface of a liquid are known as
`surfactants' `emulsifying agents' or
`detergents'.
 By reducing the surface tension, they permit
new surfaces to be produced more easily
when energy is put into the system (e.g. by
homogenisers) and thus enable larger
numbers of droplets to be formed.
Emulsifiers
 There are naturally occurring surfactants in
foods, including alcohols, phospholipids and
proteins, and these are sometimes used to
create food emulsions (e.g. using egg in cake
batters).
 However, synthetic chemicals have more
powerful surface activity and only require
very small amounts to create emulsions.
3.2 Stabilizers & Thickeners
• To control the consistency of liquid & semi-
liquid food and prevent separation of food
components during processing and storage
• other functional properties: suspending,
setting, gelling and bulking properties
 Examples:
i. Sodium alginate – stabilizer in ice cream
ii. Carrageenan - stabilizer in evaporated
milk
Stabilizers & Thickeners
• Nutritional and nutraceutical
 Arabic and guar gum, have been used as
sources of soluble dietary fibre
(nutraceutical benefits).
 Potential benefits range from cholesterol
reduction to cancer risk prevention.
 Their use in weight loss programmes is
already widespread and likely to expand
further.
3.3 Flavourings
 To impart the characteristic flavour of
flavouring
 e.g vanilin to give the flavour of vanila to ice
cream.
 To increase, complement or modify flavour
 e.g vanilin to modify the flavour of chocolate
or cocoa
 To mask the original flavour
 e.g anise to cover bitter
medicinals
3.4 Acidulants
 Compounds that can serve as buffers,
acids, alkalis & neutralizing agents
 The degree of acidity is an important
factor in the processing and
preparation of many foods
 The pH of foods may affect their colour,
texture & flavour.
Acidulants
 Examples:
 Citric acid, phosphate –
 to acidify foods,
 e.g fruit juices, jams, jellies, carbonated
beverages – minimizing heat processing
requirements & limiting the growth of
toxin-producing bacteria
 Sodium bicarbonate – leavening agent in
baking powders
3.5 Colourants
 The phase “We eat with our eyes” is trite but
true!
 Before food is tasted, before a single bite is
even taken, the quality of that food is judged
by how it looks!
 Usually the primary attributes consumers
consider in making purchasing decisions.
 For fresh fruits and vegetables, for examples,
colour is an indication of taste and flavour
quality: e.g freshness, over-ripeness or
under-ripeness
3.6 Antibrowning agents
 To retards enzymic browning – caused
darkening in fruit juices, dried fruit &
vegetables, frozen prawn, etc
 Addition of vitamin C, citric acid or
sodium sulphite will interfere with
dark colour pigment formation
 Sulphur dioxide – used in fruit juices,
dried fruits.
3.7 Dough conditioners
• To modify protein & starch in cereal-based
foods – result in improved properties such as
reduced mixing time & increased loaf
volume
• To produce more uniform bakery products
with good crumb texture
• Examples:
Various phosphates
Sulfates
Enzymes
3.8 Humectants
 Humectants aid in the retention of moisture
and prevent the drying out of certain types of
confections and of shredded coconut.
 Examples:
Inclusion of propylene glycol to shredded
coconut to keep it moist,
E.g. Glycerine, Sorbitol
3.9 Curing agents
 The pink colour of cured meats is developed
and fixed by the addition of small amounts of
sodium nitrite.
 The nitrite also inhibits the activity of
Clostridium botulinum which may be
present in the meat.
 Carcinogenic substances called
nitrosamines may be produced when nitrite
combines with secondary amines under
appropriate conditions.
 For this reason, the level of nitrite in cured
meats can be carefully regulated.
3.10 Anticaking agents
 To prevent caking, lumping & agglomeration
during storage
 It is added to dry ingredients such as salt,
powdered sugar, finely ground spice blends
 Examples:
 Calcium silicate in salt mixtures
3.11 Firming agent
 To maintain desirable crispiness /
texture in various food systems
 Examples:
Alum is used in pickles
Various calcium salts are used to
maintain firmness in canned whole
tomatoes
Alum
3.12 Sweeteners
• Sugars, hydrolysed starches, and also a
number of chemical compounds are found to
have sweetening properties.
• Nutritive sweeteners – defined as products
that have > 2% of the caloric value of sucrose
per equivalent unit of sweetening capacity,
 e.g. high fructose corn syrup (HFCS) which
is used as a replacement for sucrose in
carbonated beverages.
Sweeteners
 Nonnutritive sweeteners – Naturally
occurring or synthetic compounds that
have elevated sweetening power
compared to sucrose.
e.g. saccharin, cyclamate, aspartame,
stevioside
 It is used in low- or reduced- calorie
foods
3.12 Preservatives
 Preservatives are substances capable
inhibiting, retarding or arresting the
growth of microorganisms
 Preservatives protect microbial growth
with public health implications,
whether of pathogenic bacteria which
cause food poisoning (e.g salmonella),
or certain moulds which form
mycotoxins (e.g aflatoxin).
Preservatives
 Examples:
 Sodium benzoate – used in
margerine, soft drinks
 Sulphur dioxide – used in fruit
juice, dried fruits
 Calcium propionate – mould and
rope inhibitors in bread
4. Food safety in Malaysia
 Legal Mandate:
 Food Act 1983
gazetted on 10th March 1983
 Food Regulations 1985
gazetted on 26th September 1985
 Enforced together on
1st October 1985
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Food safety in Malaysia
• Definition under Malaysian Food
Regulations 1985
Any safe substance that is intentionally introduced into or
on a food in small quantities in order to affect the food's
keeping quality, texture, consistency, appearance, odour,
taste, alkalinity, or acidity, or to serve any other
technological function in the manufacture, processing,
preparation, treatment, packing, packaging, transport, or
storage of the food, and that results or may be reasonably
expected to result directly or indirectly in the substance or
any of its by-products becoming a component of, or
otherwise affecting the characteristic of, the food, and
includes any preservative, colouring substance, flavouring
substance, flavour enhancer, antioxidant and food
conditioner, but shall not include nutrient supplement,
incidental constituent or salt.
4.1 GRAS Substances
• Many food additives are classified as GRAS
(Generally Regarded As Safe).
Additives are classified as GRAS when they
have been used without apparent harm for
long periods, long before regulations were
put into effect.
Example of GRAS substances: acetic acid,
alum, ascorbic acid, baking soda, benzoic
acid, caffeine, calcium citrate, corn starch,
sugar, salt, monoglycerides, lactic acid,
lecithin