Unit 4 : Food Chemistry - Carbohydrates Flashcards
(26 cards)
How many sugar molecules are in each of Monosaccharides , Disaccharides , Oligosaccharides and Polysaccharides ?
- Monosaccharides : 1 sugar molecule
- Disaccharides : 2 sugar molecules
- Oligosaccharides : 3-10 sugar molecules
- Polysaccharides : 100s of sugar molecules
What are some examples of Monosaccharides ?
- Glucose
- Fructose
- Galactose
What area some example of Disaccharides and what enzymes are used for digesting each of them?
- Sucrose - enzyme sucrase helps to digest it
- Maltose - enzyme maltase helps to digest it
- Lactose - enzyme lactase helps to digest it
Compare Lactose Intolerance with Milk allergy
- name what they are classified as and where they occur and what the reaction it is to
- Lactose intolerance : A sensitivity, occurs in gastrointestinal system and its a sensitivity to lactose
- Milk allergy : An allergy , triggered by immune system , reaction to milk protein
Sugars are hygroscopic and what does that mean ?
- It means they attract water and absorb water
Sugars are Humectants, and what does that mean?
- It means that they hold moisture in food
How does caramelization occur with sugar ?
- its dry heated at high temp, sugars melt and turn brown
How does the Maillard reaction occur with sugar?
- A non enzymatic reaction between reducing sugar and an amino acid, when they are heated the sugar and amino acids undergo a series of reaction which lead to the production of a complex mixture of brown compounds called melanoidins
How does sugar affect the freezing point?
- The higher the concentration of sugar, the lower the freezing point
How does Crystallization occur in sugars?
- When the supersaturated sugar solution is cooled , the sugar starts to separate from the water and starts to recrystallize.
- this is how candy is made
What are some examples of Oligosaccharides ?
- Raffinose
- Stachyose
- Verbascose
How are Oligosaccharides digested ?
- Humans do not have enzymes to digest oligosaccharides
- so the normal intestinal bacteria ferments them to produces gases (methane, CO2, hydrogen)
What are some examples of Polysaccharides ?
- Starches
- Fibres
- Glycogen
What are some properties of Starch and how does the digestion work ?
- pure starch is a white, tasteless, and odourless powder that is insoluble in cold water
- Enzymes are produced to digest starch and when digest it is broken down into monomers of glucose
What are 3 ways starch is used in foods
- as a thickener in foods
- as an excellent binder
- To form the gel like soft texture of baked goods
How does Dextrinization occur in starch?
- Starch is heated in the absence of water, it turns brown and breaks down a little.
How can starch be used as a sweetener ?
- Since starch is tasteless, it needs to be hydrolzued so the glucose molecules start to become free and can bind to our taste receptors , thus taste sweet.
Where is glycogen stored in humans and what is it the storage form of and how is it digested ?
- Its stored in liver and muscles
- storage form of carbohydrates in human beings
- the human body produces enzymes to breakdown glycogen
Do dietary fibre get broken down by enzymatic reaction?
- No , dietary fibre is resistant to it , as the. digestive system does not produce enzymes to break down fibres
What is another name for water soluble fibres and what do they do ?
- Viscous fibres
- They dissolve in water and increase the viscosity of the water
How do water soluble fibres impact our digestive system when consumed ?
- They increase the viscosity of chyme in our digestive system which leads to slow movement of chyme in the digestive system - aka peristalsis
How is peristalsis impacting the body ?
- It keeps the stomach full for a longer period of time and slows down the absorption of nutrients through the wall
What is another name for water insoluble fibres and what do they do ?
- Non viscous fibres
- They do not dissolve in water and thus have no impact on the viscosity of water
What do water insoluble fibres help with?
- they bind minerals. phytochemical and some vitamin
