6644754
Description
Flashcards by Lucy Waters, updated more than 1 year ago
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Created by Lucy Waters
over 7 years ago
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| Question | Answer |
| What is photosynthesis? | The process by which green plants use sunlight to make glucose. |
| How does photosynthesis occur? | Plant roots absorb water from the soil. Leaves take in CO2 from the air. Chlorophyll in leaves absorbs energy from the sun. |
| What is the result of photosynthesis? | Glucose(c6h12o6) is formed. Oxygen is released into the air. |
| Monosaccharide | 1 sugar unit. c6h12o6 glucose - fruit, fructose - honey |
| Disaccharide | 2 monosaccharides join, loss of h2o molecule. c12h22o11 maltose(glucose+glucose) - Barley Sucrose(glucose+fructose) - Table sugar |
| Polysaccharide | 3+ monosaccharides join, loss of h2o molecule with each new link. Can be straight or branched. (c6h10o5)n starch - potatoes, glycogen - meat cellulose - skin of fruit and veg |
| Properties of sugar: Solubility | sugar is a white crystalline compound. soluble in water. when dissolved it forms a syrup. used as a preservative in canned fruit e.g canned peaches |
| Sweetness | Vary in degrees of sweetness, measured on a point scale of sweetness. fructose - highest - 170% lactose - lowest - 15% |
| Assists aeration | sugar denatures egg protein, enabling aeration to occur. e.g making of sponges - the egg when whisked with sugar becomes aerated. |
| Maillard Reaction | Non-enzymic browning of food due to a reaction between certain amino acids and sugars under dry heat. Brown colour and a crust. e.g roast meat |
| Caramelisation | On heating, sugar melts and caramelises. 10 gradual stages. 104-177 occurs at 160 degrees. If overheated (177) caramel will carbonise. e.g caramel squares |
| Crystallisation | occurs if more sugar is added than can be absorbed by a liquid. Crystal particles form when the solution is cooled. e.g. fudge |
| Hydrolysis | Is the chemical breakdown of a molecule by adding water to produce smaller molecules. occurs when water is added to a disaccharide to produce 2 monosaccharides. reverse of condensation reaction |
| Inversion | occurs when water and acids or enzymes split sucrose into glucose and fructose. This is an invert sugar and is much sweeter than sucrose. e.g. jam making |
| Properties of starch Solubility | white non-crystalline powder. insoluble in cold water. |
| Flavour | Is not sweet. |
| Hygroscopic | This property relates to how starch absorbs moisture from the air e.g. soften biscuits if they are not kept air tight. |
| Gelatinisation | When starch is heated in the presence of water, starch grains swell, burst and absorb the liquid. (thickening) As temp. rises the mixture becomes more viscous and forms a sol. On cooling this turns into a gel. e.g. moist heat - lemon curd |
| Dextrinisation | Dextrins are shorter chains of starch, when heated they become long-chained pyrodextrins. Resulting in a colour change on the outer surface of the food. e.g. browning of bread to make toast. |
| Hydrolysis | is a chemical breakdown of a molecule by adding water to produce smaller molecules water & acid split starch into maltose. |
| Properties of non-starch polysaccharides Cellulose/ Dietary fibre | Can absorb large amounts of water, cannot be digested. helps stimulate peristalsis preventing bowel disorders. insoluble in water. |
| Gums | soluble in water. Have the ability to absorb large amounts pf water to form a thick gel with a firm texture. e.g. ice cream |
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