Transcript Lecture Food ingredients and functionsx

Food ingredients and functions
Definition
Types
Functions
Definitions
• Food is any substance or materials eaten or drunk to
provide nutritional support for the body or for
pleasure. It usually consists of plant or animal origin,
that contains essential nutrients, such as
carbohydrates, fats, proteins, vitamins, or minerals,
and is ingested and assimilated by an organism to
produce energy, stimulate growth, and maintain life.
• Food ingredients have been used for many years to
preserve, flavour, blend, thicken and colour foods, and
have played an important role in reducing serious
nutritional deficiencies among consumers.
Definition contd.
• An ingredient is a substance that forms part of a
mixture (in a general sense).
• For example, in cooking, recipes specify which
ingredients are used to prepare a specific dish.
• Many commercial products contain a secret
ingredient that is purported to make them better
than competing products. In the pharmaceutical
industry, an active ingredient is that part of a
formulation that yields the effect required by the
customer.
Prime food ingredients
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Flour
Sugar
Eggs
Fats/Oils
Function of flour
• Wheat flour is the most important ingredient
in home baking.
• There are many different types of flour, such
as stone ground, wholemeal and cookie flour.
• Flour as an ingredient has many different
and important functions?
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Provides fibre (especially if wholemeal)
If Self-Raising, makes mixtures rise
Thickens sauces
Forms the bulk of bread, pastry and cake
mixes
• If wholemeal, provides colour and texture
• Gluten in flour produces a stretchy dough
• Provides carbohydrate, Vitamin B, calcium
and iron
Sugar
• Ever tasted a sugar-free cookie?
• Some people may even cringe at the thought
of having no sugar to dip their strawberries
into! Well, although it does it well, making
things sweet isn't the only thing that sugars
good for.
Functions of Sugar
• Provides sweetness
• If brown, provides colour and texture
• Large amounts prevent micro-organism growth
(for example, jam/marmalade)
• Caramelises to produce a brown colour
• Retains moisture
• Helps to trap air in cake mixtures
• Provides carbohydrate
Eggs
• Hold air when beaten
• Coagulate (sets) when heated
• Add colour to mixtures Thickens sauces,
custards, etc.
• Glaze bread, scones and pastry
• Bind ingredients together
• Provide protein, fat, iron and Vitamins A, B,
and E
• Glaze bread, scones and pastry
• Bind ingredients together
• Provide protein, fat, iron and Vitamins A, B,
and E
Fats and oils
• They may not be that good for you, but fats
and oils are definitely essential ingredients in
many, many dishes.
• Provide flavour
• Keep products moist and extend shelf-life
• Add colour to foods
• Make pastry 'short' by coating the flour to
stop gluten developing
Food additives
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 :
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the food's keeping quality, texture, consistency,
appearance, odour, taste, alkalinity, or acidity,
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or to serve any other technological function in the
manufacture, processing, preparation, treatment, packing,
packaging, transport, or storage of the food,
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and that results or may be reasonably expected to result
directly or indirectly in the substance or any of its byproducts 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.
GRAS additives
• 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
Types of food additives
List of food ingredient additives
1. Preservatives
2. Sweeteners
3. Colour Additives
4. Flavours and Spices
5. Flavour Enhancers
6. Fat Replacers (and components of
formulations used to replace fats)
7. Nutrients
8. Emulsifiers
List of food ingredient additives
9. Stabilizers and Thickeners, Binders,
Texturizers
10. pH Control Agents and acidulants
11. Leavening Agents
12. Anti-caking agents
13. Humectants
14. Yeast Nutrients
15. Dough Strengtheners and Conditioners
16. Enzyme Preparations
17. Gases
18. Curing agents
How are ingredients listed on a product
label?
• Food manufacturers are required to list all ingredients in the food on the
label.
• On a product label, the ingredients are listed in order of predominance,
with the ingredients used in the greatest amount first, followed in
descending order by those in smaller amounts.
• The label must list the names of any FDA-certified colour additives (e.g.,
FD&C Blue No. 1 or the abbreviated name, Blue 1). But some ingredients
can be listed collectively as "flavours," "spices," "artificial flavouring," or in
the case of colour additives exempt from certification, "artificial colours",
without naming each one.
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Declaration of an allergenic ingredient in a collective or single colour,
flavour, or spice could be accomplished by simply naming the allergenic
ingredient in the ingredient list.
1. Preservatives
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Names on labels
Ascorbic acid, citric acid, sodium benzoate, calcium propionate, sodium
erythorbate, sodium nitrite, calcium sorbate, potassium sorbate, BHA, BHT, EDTA,
tocopherols (Vitamin E)
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What they do?
Prevent food spoilage from bacteria[Salmonella producing food poisoning],
molds, fungi [Aspergillus aflatoxin], or yeast (antimicrobials); slow or prevent
changes in colour, flavour, or texture and delay rancidity (antioxidants); maintain
freshness
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Examples of uses
Fruit sauces and jellies, beverages, baked goods, cured meats, oils and
margarines, cereals, dressings, snack foods, fruits and vegetables
Examples:
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– Sodium benzoate – used in margarine, soft drinks
– Sulphur dioxide – used in fruit juice, dried fruits
– Calcium propionate – mould and rope inhibitors in bread
2. Sweeteners
• Names Found on Product Labels
Sucrose (sugar), glucose, fructose, sorbitol, mannitol, corn
syrup, high fructose corn syrup, saccharin, aspartame,
sucralose, acesulfame potassium (acesulfame-K), neotame
• What they do?
Add sweetness with or without the extra calories
• Examples of uses
Beverages, baked goods, confections, table-top sugar,
substitutes, many processed foods
2i. Sweeteners
• Include many sugars and hydrolysed starches
and also a number of chemical compounds
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
2ii. Sweeteners
• Nonnutritive sweeteners – Naturally
occurring or synthetic compounds that have
elevated sweetening power compared to
sucrose, e.g. saccharin, cyclamate,
aspartame, stevioside
• Used in low- or reduced- calorie foods
2iii. Do low-calorie sweeteners cause
adverse reactions?
• No. Food safety experts generally agree there is no convincing evidence
of a cause and effect relationship between these sweeteners and
negative health effects in humans. Food and Drug Administration (FDA)
of America has monitored consumer complaints of possible adverse
reactions for more than 15 years.
• For example, in carefully controlled clinical studies, aspartame has not
been shown to cause adverse or allergic reactions.
• However, persons with a rare hereditary disease known as
phenylketonuria (PKU) must control their intake of phenylalanine from
all sources, including aspartame. Although aspartame contains only a
small amount of phenylalanine, labels of aspartame-containing foods
and beverages must include a statement advising phenylketonurics of
the presence of phenylalanine.
• Individuals who have concerns about possible adverse effects from food
additives or other substances should contact their physicians.
3. Colour Additives
• Names Found on Product Labels
1)
Certified colours are synthetically produced (or human made) and
used widely because they impart an intense, uniform colour, are less
expensive, and blend more easily to create a variety of hues. Certified
food colours generally do not add undesirable flavours to foods.
Examples: FD&C Blue Nos. 1 and 2, FD&C Green No. 3, FD&C Red Nos. 3
and 40, FD&C Yellow Nos. 5 and 6, Orange B, Citrus Red No. 2
2)
Colours that are exempt from certification include pigments derived
from natural sources such as vegetables, minerals or animals. Nature
derived colour additives are typically more expensive than certified
colours and may add unintended flavours to foods. Examples of exempt
colours include annatto extract (yellow), dehydrated beets (bluish-red to
brown), caramel (yellow to tan), beta-carotene (yellow to orange) and
grape skin extract (red, green), saffron (orange), fruit / vegetable juices.
3i. Colour Additives
• What they do?
Offset colour loss due to exposure to light, air,
temperature extremes, moisture and storage
conditions; correct natural variations in colour;
enhance colours that occur naturally; provide
colour to colourless and "fun" foods
• Examples of uses
Many processed foods, (candies, snack foods
margarine, cheese, soft drinks, jams/jellies,
gelatins, pudding and pie fillings)
3ii. Colour Additives
• Are certain people sensitive to FD&C Yellow No. 5 in
foods?
A FD&C Yellow No. 5, is used to colour beverages,
dessert powders, candy, ice cream, custards and other
foods. FDA's Committee on Hypersensitivity to Food
Constituents concluded in 1986 that FD&C Yellow No. 5
might cause hives [hyperactivity] in fewer than one out
of 10,000 people. It also concluded that there was no
evidence the colour additive in food provokes asthma
attacks. The law now requires Yellow No. 5 to be
identified on the ingredient line. This allows the few
who may be sensitive to the colour to avoid it.
3iii. What is the role of modern
technology in producing food additives?
• Many new techniques are being researched that will
allow the production of additives in ways not
previously possible.
• One approach is the use of biotechnology, which can
use simple organisms to produce food additives. These
additives are the same as food components found in
nature.
• In 1990, FDA approved the first bioengineered enzyme,
rennin, which traditionally had been extracted from
calves' stomachs for use in making cheese.
3iv. Do additives cause childhood hyperactivity?
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Although this hypothesis was popularized in the 1970's, results from studies on this issue
either have been inconclusive, inconsistent, or difficult to interpret due to inadequacies in
study design.
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A Consensus Development Panel of the National Institutes of Health concluded in 1982 that
for some children with attention deficit hyperactivity disorder (ADHD) and confirmed food
allergy, dietary modification has produced some improvement in behaviour.
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However, a 1997 review published in the Journal of the American Academy of Child &
Adolescent Psychiatry noted there is minimal evidence of efficacy and extreme difficulty
inducing children and adolescents to comply with restricted diets. Thus, dietary treatment
should not be recommended, except possibly with a small number of preschool children who
may be sensitive to tartrazine, known commonly as FD&C Yellow No.5
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In 2007, synthetic certified colour additives again came under scrutiny following publication
of a study commissioned by the UK Food Standards Agency to investigate whether certain
colour additives cause hyperactivity in children. Both the FDA and the European Food Safety
Authority independently reviewed the results from this study and each has concluded that
the study does not substantiate a link between the colour additives that were tested and
behavioural effects.
4. Flavours and Spices
• Names Found on Product Labels
Natural flavouring, artificial flavour, and spices
• What they do?
Add specific flavours (natural and synthetic)
• Examples of uses
Pudding and pie fillings, gelatin dessert mixes,
cake mixes, salad dressings, candies, soft drinks,
ice cream, BBQ sauce
5. Flavour Enhancers
• Names Found on Product Labels
Monosodium glutamate (MSG), hydrolyzed soy protein,
autolyzed yeast extract, disodium guanylate or
inosinate
• What they do?
Enhance flavours already present in foods (without
providing their own separate flavour)
• Examples of uses
Many processed foods
6. Fat Replacers (and components of
formulations used to replace fats)
• Names Found on Product Labels
Olestra, cellulose gel, carrageenan, polydextrose, modified
food starch, microparticulated egg white protein, guar gum,
xanthan gum, whey protein concentrate
• What they do?
Provide expected texture and a creamy "mouth-feel" in
reduced-fat foods
• Examples of uses
Baked goods, dressings, frozen desserts, confections, cake
and dessert mixes, dairy products
7. Nutrients
• Names Found on Product Labels
Thiamine hydrochloride, riboflavin (Vitamin B2), niacin, niacinamide,
folate or folic acid, beta carotene, potassium iodide, iron or ferrous
sulfate, alpha tocopherols, ascorbic acid, Vitamin D, amino acids (Ltryptophan, L-lysine, L-leucine, L-methionine)
• What they do?
Replace vitamins and minerals lost in processing (enrichment), add
nutrients that may be lacking in the diet (fortification)
• Examples of uses
Flour, breads, cereals, rice, macaroni, margarine, salt, milk, fruit
beverages, energy bars, instant breakfast drinks
7 i. How are nutrients are added to
fortified cereals?
• Adding nutrients to a cereal can cause taste and colour changes in
the product. This is especially true with added minerals. Since no
one wants cereal that tastes like a vitamin supplement, a variety of
techniques are employed in the fortification process.
• In general, those nutrients that are heat stable (such as vitamins A
and E and various minerals) are incorporated into the cereal itself
(they're baked right in).
• Nutrients that are not stable to heat (such as B-vitamins) are
applied directly to the cereal after all heating steps are completed.
Each cereal is unique -- some can handle more nutrients than
others can. This is one reason why fortification levels are different
across all cereals.
7ii. Is a naturally produced ingredient safer
than an artificially manufactured ingredient?
What is the difference between natural and artificial ingredients?
• A Natural ingredients are derived from natural sources (e.g.,
soybeans and corn provide lecithin to maintain product consistency;
beets provide beet powder used as food colouring).
• Other ingredients are not found in nature and therefore must be
synthetically produced as artificial ingredients.
• Also, some ingredients found in nature can be manufactured
artificially and produced more economically, with greater purity and
more consistent quality, than their natural counterparts.
• For example, vitamin C or ascorbic acid may be derived from an
orange or produced in a laboratory. Food ingredients are subject to
the same strict safety standards regardless of whether they are
naturally or artificially derived.
8. Emulsifiers
• Names Found on Product Labels
Gelatin, pectin, guar gum, carrageenan, xanthan gum, whey
• What they do?
i. Allow smooth mixing of ingredients, prevent
separation
ii. Keep emulsified products stable, reduce stickiness,
control crystallization, keep ingredients dispersed,
and to help products dissolve more easily
• Examples of uses
Frozen desserts, dairy products, cakes, pudding and gelatin
mixes, dressings, jams and jellies, sauces
9. pH Control Agents and acidulants
• Names Found on Product Labels
Lactic acid, citric acid, ammonium hydroxide,
sodium carbonate
• What they do?
Control acidity and alkalinity, prevent spoilage
• Examples of uses
Beverages, frozen desserts, chocolate, low
acid canned foods, baking powder
10. Leavening Agents
• Names Found on Product Labels
Baking soda, monocalcium phosphate, calcium
carbonate
• What they do?
Promote rising of baked goods
• Examples of uses
Breads and other baked goods
11. Anti-caking agents
• Names Found on Product Labels
Calcium silicate, iron ammonium citrate, silicon
dioxide
• What they do?
Keep powdered foods free-flowing, prevent
moisture absorption
• Examples of uses
Salt, baking powder, confectioner's sugar
12. Humectants
• Names Found on Product Labels
Glycerin, sorbitol
• What they do?
Retain moisture
• Examples of uses
Shredded coconut, marshmallows, soft candies,
confections
13. Yeast Nutrients
• Names Found on Product Labels
Calcium sulfate, ammonium phosphate
• What they do?
Promote growth of yeast
• Examples of uses
Breads and other baked goods
14. Dough Strengtheners and
Conditioners
• Names Found on Product Labels
Ammonium sulfate, azodicarbonamide, L-cysteine
• What they do?
Produce more stable dough
• Examples of uses
Breads and other baked goods
15. Firming Agents
• Names Found on Product Labels
Calcium chloride, calcium lactate
• What they do?
Maintain crispness and firmness
• Examples of uses
Processed fruits and vegetables
16. Enzyme Preparations
• Names Found on Product Labels
Enzymes, lactase, papain, rennet, chymosin
• What they do?
Modify proteins, polysaccharides and fats
• Examples of uses
Cheese, dairy products, meat
17. Gases
• What they do?
Serve as propellant, aerate, or create
carbonation
• Examples of uses
Oil cooking spray, whipped cream, carbonated
beverages
18. 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
Functional properties
• Many foods or ingredients have functional properties. Some compounds
such as dietary fibre, have been widely consumed for many years. Dietary
fibres commonly found in our food supply include wheat bran, oat bran,
barley bran, rice bran and psyllium. Insoluble fibres (such as wheat bran)
aid digestion and appear to help prevent colon cancer and heart disease.
Soluble fibres (such as oat bran and psyllium) have been shown to help
lower cholesterol levels.
• Polyunsaturated fatty acids are often added to functional foods. Some of
the more common ones are omega-3 fatty acids, which have been linked
to cholesterol reduction, and eicosapentanoic acid (EPA) that has been
shown to reduce blood clottIng.
• Other functional ingredients that are often added to foods include
proteins, oligosaccharides (thought to promote the growth of healthy
intestinal bacteria) and " good" bacteria such as bifidus and acidophilis.
Common Functional foods
Functional Foods Available Now
• Margarine containing plant stanols to help lower blood
cholesterol
• Breakfast cereals and pastas with soluble fibre to help
lower cholesterol
• Fermented drinks and yoghurts with probiotic bacteria
claimed to boost immunity and improve digestion
• Enzyme-enriched drinks and snack bars to aid digestion
• Juices and drinks with added calcium to help tooth and
bone health
Foods versus medicine
• The use of foods as medicines dates back many centuries.
Hippocrates is quoted as saying "Let food be thy medicine
and medicine be thy food".
• In Asian cultures, the line between foods and medicines has
traditionally been blurred. Foods have been used for
hundreds of years as treatments to cure or prevent
ailments.
• The increasing sales of supplements and foods perceived to
be healthy reflect the growing levels of health
consciousness throughout Asia. And this trend is expected
to continue as governments mount campaigns to arrest the
growing burden of lifestyle-related diseases on national
health bills.