the science of food Flashcards
appetite
the desire to eat (hypothalamus monitors + sends messages that create feelings of hunger + thirst)
ghrelin is a appetite enhancing hormone in the stomach - makes growling sound
satiety
the feeling of being full after consuming an adequate amount of food.
hunger
The physiological need by the body to eat.
sensory properties of food
The sensory properties of food are related
to the five human senses: sight, smell, sound,
touch and taste. All of these are important in
the way we develop a like or dislike for foods.
Our perception of food is ruled by these
senses, as is our appreciation of food.
appearance
Appearance relates to the sight of food. What
does it look like? This is the dominating sense
when it comes to food choices. If the food
does not look appealing to you, then do you
want to eat it?
taste
There are five basic tastes. Each of these
leaves a lasting impression when we eat a
food item.
The flavour of a food item is a combination
of taste and aroma. The mouth and nose
send signals to the brain. This contributes to
whether we like or dislike a food. The flavour
or taste of the food is determined by our
taste buds on the tongue.
texture
Feeling the texture of the food inside your
mouth is so important.
When we bite, chew and swallow food, this
all impacts on our appreciation or dislike for
a food item.
aroma
The smell of food can either make us want to
eat it or turn us right off.
Simply smelling
a food item can arouse a mouth-watering
response and create an appetite or feeling of
hunger.
sensory appreciation of food
how sensory properties influence digestive response?
they allow to describe why we like and dislike foods, they send messages to the brain enticing to eat. stomach contractions can begin at sight or aroma of food - signalling that we are hungry which signals intestinal + salivary glands to start producing digestive chemicals.
macronutrients
vital energy-
yielding nutrients
that are required
in large quantities
by the body;
carbohydrates,
including dietary fibre, fats and proteins
carbohydrates
Carbohydrates are the preferred source of energy for the body. They provide satiety value. There are two types of carbohydrates:
simple carbohydrates and complex
carbohydrates.
fibre
Fibre is an indigestible carbohydrate
found in plant foods that provides satiety value and contributes to good health.
Fibre assists food to move through the digestive system.
There are three types of fibre: soluble, insoluble and resistant fibre.
protein
All cells in the body contain protein. Protein is made up of amino acids.
These must be included in your diet so that your body can function. The amount of protein required by the body is based on different things such as age or sex etc
fats
Fats can increase the taste and textural pleasure of food, and some oils made from fruits, seeds, grains or nuts are essential in a healthy diet.
the four types of fats, polyunsaturated fats, monounsaturated fats, saturated fats and trans fats.
It is important to remember
that many food sources containing fat are considered discretionary choices.
digestion
the process of breaking down food into smaller substance.
This allows the body to use the nutrients found in the food that we eat. Once these nutrients have been broken down into these smaller substances, they can be absorbed and used by the body for energy, growth, repair and maintenance of
bodily needs and functions.
digestive system step 1
digestive system begins before food hits the tongue. glands in the mouth start to pump out saliva
MOUTH:
chewing is breaking down food from the teeth and kneading by the tongue turning food into bolus. Salivary amylase breaks down starches and sugars (carbs) into dextrins and monosaccharides. Lingual lipase breaks down fats
digestive system step 2
OESOPHAGUS:
once swallowed, peristalsis (muscle contractions) massage the bolus into the stomach or propels.
- nerves in the tissue sense bolus and trigger peristalsis
digestive system step 3
STOMACH:
a churning action in the stomach turns bolus into chunks. Hormones secreted by cells in the lining trigger the release of acids and enzymes (hyaluronic acid, lipase and amylase). from the stomach wall start to dissolve food and break down proteins. (hydrochloric acid activates pepsin which breaks down proteins into amino acids). Hormones alert pancreas, liver and gallbladder to produce digestive juices and transfer bile. 3 hours later stomach bolus is now chyme.
digestive system step 4
SPHINCTER: opens up to the
SMALL INTESTINE: peristalsis pushes chyme through the small intestine. Chyme mixes with bile and amylase breaks down sugars. Villi lines the intestine (jejunum and ileum) which absorbs nutrients, water and amino acids, fats and glucose into the bloodstream.
digestive system step 5
LARGE INTESTINE:
leftover fibre, water and dead cells go into the large intestine (colon) which contains gut bacteria. Absorption occurs again and absorbs leftover fluid- making stool which goes into the»_space;». step 6 (rectum)
what does bile do?
produced in the liver, gall bladder, the GB stores + releases bile into the sml intestine. in the sml intestine the bile breaks down fat into fatty acids + glycerol
carbohydrates digestion
- Starts in the mouth (CHO broken down into simple sugars by salivary amylase, salivary amylase begins to break polysaccharides + disaccharides into dextrins + monosaccharides.)
- Small intestine (enzymatic hydrolysis occurs + CHO are broken down into simple sugars by enzymes such as pancreatic amylase, enzymatic hydrolysis completes the breakdown of CHO into simple sugars, glucose, fructose, and/or galactose)
- Fibre is undigestible + is used to add bulk to the bowel.
