Transcript File - Stage 6 Food Technology Syllabus

Physiological Factors Affecting
Food Selection
• Hunger, Appetite & Satiety ✓
• Nutritional Requirements ✓
• Reactions to Food
Reactions to Food
• Individuals select or reject food based on their reaction to the
food’s physical appearance, its presentation, smell and
texture.
• Sensory Perceptions: using our senses to gauge and judge the
quality and appeal of food.
• Attractive colours and the creative arrangement of food
stimulates the appetite and salivary glands.
Image: Burger
Project, World Square.
Jajo (2015).
Image: La Mono,
Merrylands. Jajo (2015)
Appearance
Colour:
• The colour of food indicates its quality and
nutritional value.
• Alterations in colour are one of the first signs of food
spoilage.
• Some colours rarely occur naturally in foods, so their
use in manufactured foods is limited.
Image: Heinz introduced coloured ketchup. It did not last on
the market for long.
EXPERIMENT: Sensory Reactions to
Cupcakes
Aim: To determine the effects of
colour on the acceptability and
appeal of food.
Red, Vanilla, Green and Black
coloured cupcakes were used to
determine how colour
influences food selection.
How does colour affect appetite?
Image: White Rice with
Grilled Chicken and White
Sauce.
Image: White Rice with
Marinated, Roast Chicken
topped with a garnish.
Shape:
• The shape of food influences its appeal. Pictures in recipe
books show how important shape is in the presentation of a
meal.
• One of the recent innovations in the shape of food is the
change in portion size for well-known products.
Turgor:
• Turgor refers to the pressure placed on cell walls or membranes by
fluids within the cell.
• Turgor gives many foods a full, fresh appearance, a firm texture and
crisp mouthfeel.
• How does turgor influence food selection?
Image: Fresh Capsicum. Very Turgid.
Image: Wilted Capsicum. Non Turgid.
Textural differences in foods create interest in meals and
stimulate the appetite.
Image: Soft, fluffy rice with
firm meat and
crisp vegetables.
Image: Crunchy, flakey short crust pastry
with creamy custard filling and crisp berries.
https://www.youtube.com/watch?v=EyD9_Ct0DIs
Flavour
• Flavour is a sensory impression of food based on its taste and
smell.
• Our body uses taste sensors on the tongue to detect
differences in flavour, with the help of the sense of smell.
• The mouth contains 9000 to 10,000 taste receptors, also
known as ‘tastebuds’. Most are located on the tongue, others
are located on the roof of the mouth and the back of the
throat.
• When you eat a particular food and the tastebud had been
stimulated, the tastebud sends a nerve impulse to the brain,
which registers that particular taste sensation.
Aroma
• Aroma describes how something smells. In our nose there are
odour receptor nerves that transmit signals to the
hypothalamus in the brain.
• Taste and aroma are related; many foods give off aromas that
can be smelled before the food is eaten, as well as when the
food is eaten.
• Another word used to describe the smell of something is
‘odour’. Normally when we describe the food as having an
odour, it indicates a lack of freshness. For example; sour milk.
Allergies
A food allergy occurs when your immune system responds to a
food it mistakenly believes is harmful. When the food is eaten,
the immune system immediately releases antibodies in order to
destroy the food.
This reaction between the allergen and the antibodies causes
the symptoms of the allergy, which can be dramatic and life
threatening, even with only very tiny amounts of the allergen
present.
• The reactions vary between individuals but may include
abdominal swelling, vomiting, diarrhoea, itches and skin
rashes, wheezing, headaches and disturbed sleep.
• Common food allergens include; cow’s milk, shellfish, eggs,
peanuts, wheat and soy.
On the other hand, a food intolerance occurs when the nerve
endings in different parts of the body become irritated, causing
symptoms such as; stomach & bowel troubles, headaches,
swelling or hives.
EXAMPLE:
In people with coeliac disease (gluten intolerance) the immune
system reacts abnormally to gluten (a protein found in wheat,
rye, barley and oats), causing small bowel damage.