Home Economics Past Paper 2024-2025 PDF

Subject Home Economics TEACHER Mella Brophy COURSE 5th Form ACADEMIC LEVEL ACADEMIC YEAR 2024-2025 TOPIC Carbohydrates STUDENT NAME: CONTENTS Mella Brophy. Home Economics. 5th Form. 2024-2025. Carbohydrates  Plant roots absorb water (H20) from the soil  Leaves take...

Subject Home Economics TEACHER Mella Brophy COURSE 5th Form ACADEMIC LEVEL ACADEMIC YEAR 2024-2025 TOPIC Carbohydrates STUDENT NAME: CONTENTS Mella Brophy. Home Economics. 5th Form. 2024-2025. Carbohydrates  Plant roots absorb water (H20) from the soil  Leaves take in carbon Dioxide (CO2) from the soil.  Chlorophyll (green pigment) in leaves absorb energy from the sun. THE RESULT  Glucose (sugar) is formed  Oxygen (O2) is released into the air. 6 CO2 + 6H2O Light C6H1206 + 602 Carbon Dioxide Water Chlorophyll Glucose Oxygen Elemental Composition Carbon (C), Hydrogen (H) and Oxygen (O) Classification according to structure  All carbohydrates are based on simple sugar units.  Carbohydrates are classified into three main groups: Monosaccharides Disaccharides Polysaccharides Mella Brophy Home Economics 6th form 2024-2025 4 Monosaccharides Structure Chemical Examples Sources formula A simple sugar that Glucose Fruit contains one single C6H1206 Fructose Fruit and sugar unit. It is the Galactose honey samllest unit of a Digested carbohydrate. milk Disaccharides Structure Chemical Examples Sources formula Two Sucrose = Table sugar monosaccharides C12H22011 (glucose +fructose) joined together Maltose = Barley with the loss of (Glucose +glucose) water Lactose = Milk (condensa on) (glucose+galactose Glycosidic Link (Ring structures) Mella Brophy Home Economics 6th form 2024-2025 5 Polysaccharides Polysaccharides Chemical formula Examples Sources Polysaccharides are (C6H1005) n cellulose Skins of fruit complex (n is the number of monosaccharides in dietary fibre and vegetables carbohydrates the chain) composed of long Starch Cereals and chains of potatoes monosaccharide glycogen Meat units linked together with the loss of water. They can be a straight chain of monosaccharides known as linear polysaccharides, or can be branched known as a branched polysaccharide. Linear Branched Amylose Amylopec n Mella Brophy Home Economics 6th form 2024-2025 6 Non Stach poly Soluble Fibre Pec n & oatmeal, nuts, saccharides (NSP) turns into a glue-like Gums apples, are Indiges ble, substance and absorbs &blueberries thick gel-forming things like fat and sugar barley, seed fibres that help hold from other food sources, husks, flaxseed plant cell walls and releases them slowly legumes – together. Fibre throughout the day. dried beans, absorbs water in the Despite the fact that fibre lentils, peas intes ne. itself is not digested, it helps give you energy throughout the day. aids in lowering glucose and cholesterol levels. Insoluble fibre Cellulose wheat bran, doesn’t dissolve in water RDA FIBRE corn bran, rice but retains 25-30g per bran the skins it to so en and build up day of fruits and stool to keep the waste vegetables food (faeces) so and whole wheat bulky so it is removed bread, brown from the body quickly rice, quinoa and efficiently. Lack of fibre results in cons pa on causing discomfort and in extreme cases diver culi s -may require surgery Mella Brophy Home Economics 6th form 2024-2025 7 Properties of Carbohydrates Sugars, starch and non-starch polysaccharides each have unique properties and culinary applications. Properties of sugar Property Explana on Culinary applica on 1. Solubility Sugar is a sweet crystalline Used as a compound, soluble in water and preserva ve – by increasing the temperature of canned fruit, jams the solu on even more sugar can dissolve to make a syrup. 2. Sweetness Sugar has varying degrees of Sweetens cakes, sweetness based on a point scale custards, desserts using the tas ng method and beverages, fruit Fructose has a rela ve sweetness of 170 Sucrose rela ve sweetness of 100 Lactose rela ve sweetness of 15 3. Crystallisa on This occurs if more sugar is added Confec onery, Fudge than can be absorbed by a liquid, and sweet industry satura on. Undesirable in Jam 1:1 ra o fruit to sugar. Crystal par cles are formed when the mixture cools 4. Maillard reac on Sugar (Carbohydrate) + Amino Browning of toast, Non-enzymic Acids + Dry Heat >1400C. The roast potatoes, baked browning (see OH (hydroxyl group) of the sugar goods, seared meats protein notes) chemically reacts with the NH2 (amino group) of the amino acid resul ng in Food browning. Melanoidins Mella Brophy Home Economics 6th form 2024-2025 8 5. Carmelisa on Non enzymic browning: When Caramel sauce, sugars are heated in dry heat, desserts - caramel they melt and produce a range of squares, Crème brown substances known as brûlée caramel. Happens over ten gradual stages between sugar mel ng and caramelisa on (1600C) These stages occur between 104°C & 177°C Eventually, the heat will cause carbonisa on (burning) 800C this mixture becomes even more viscous, forming a sol (A sol contains par cles that do not fully dissolve but are evenly dispersed throughout the liquid) On cooling, this becomes a gel Note on Gelatinisation 1. 2. 3. 4. Mella Brophy Home Economics 6th form 2024-2025 10 4. Dextrinisa on When starch foods are dry- Toas ng bread, baked heated, typically above 150°C goods, toasted short-chained polysaccharides breakfast cereals, (sugars) called dextrins are formed. “pyrodextrins” refers to dextrins created specifically through dry heat exposure, "pyro-" means "heat." causes a colour change on the surface of the food, resul ng in an a rac ve brown appearance. Properties of Non-Starch Polysaccharides Property Explana on Culinary use Gum/gel forma on Pec n found in fruit and vegetables. Se ng jams & Protopec n (pectose) in under ripe jellies fruit to pec n in ripe fruit to pec c acid in over ripe fruit. When pec n is heated in the presence of acid Jam PH 3.5 and sugar, 65%, water becomes trapped. The long chains of polysaccharides cool to form a gel (See Note below) 1. Jam making: hea ng fruit in water with acid, pec n is extracted from the cell walls of the fruit. Pec n chains are short and too diluted in water to form a long, con nuous network. Water molecule Pectin Chain The pectin chains (orange) are short and spread out in the solution of water (blue). Mella Brophy Home Economics 6th form 2024-2025 11  2. Once the pec n has been extracted, sugar is added. The sugar molecules, are hygroscopic, a ract water molecules in the solu on, allowing the pec n chains to come into closer proximity with one another. The water-attracting sugar molecules bind to some of the water, allowing the pectin chains to drift closer together. 3. The mixture is brought to a boil. This further reduces the overall water content, evapora on, allowing the pec n chains to press even closer together. The mixture is cooked to 1040C. At this temperature enough water has evaporated to create a sugar concentra on that will allow the pec n to bond. The final sugar content should be between 60-65% represen ng the combined solid content of the sugar and fruit solids). As water evaporates through boiling, the sugar concentration increases. 4. The pec n forms an interconnected mesh that holds remaining free standing water and creates the final gel texture of jam. Mella Brophy Home Economics 6th form 2024-2025 12 Effects of heat on carbohydrates Dry heat Moist heat  Carbohydrate foods brown due  Cellulose so ens, e.g. cooked to the presence of dextrins, e.g. vegetables Toast  Starch grains swell, burst &  Sugar caramelises, e.g. Caramel absorb liquid, e.g. flour used to slices thicken sauces  Maillard reac on occurs because  Pec n is extracted by hea ng of the interac on between sugar fruit in water with sugar & acid, & amino acids, e.g. roast e.g. jam making potatoes  Sugar dissolves in warm liquid, e.g. making syrups Biological functions of carbohydrates Starches & sugar Cellulose (NSP) Carbohydrates are used for heat Soluble - pec ns, gums e.g. in oats and energy for the body. 1g = 4Kcal and rye absorb water and help to of energy (17KJ). Maintains body reduce (LDL) cholesterol by temperature at 370C blocking its absorp on They spare protein so it can be used Insoluble fibre absorbs water for growth and repair. crea ng bulk and s mulates Excess carbohydrate is changed to peristalsis which moves food glycogen and stored in liver and through the intes ne preven ng muscle as an energy reserve or it is cons pa on. changed to body fat (adipose RDA 30g ssue) which insulates the body. Mella Brophy Home Economics 6th form 2024-2025 13 The glycaemic index (GI) The glycaemic index (GI) is a way of ranking carbohydrate-containing foods based on how slowly or quickly they are digested and increase blood glucose levels over a period of time – usually 2 hours. A low glycemic index diet is one based on foods that won’t cause wild swings in your blood sugar. “Eating foods with a lower glycemic index means they will cause a slower and lower rise in your blood sugar. This helps absorb food more slowly and stay full for longer, and therefore eat less. “Foods with a high glycemic index, or simple sugars, give you a quick burst of energy with a rise in blood sugar quickly, but then tend to leave you feeling pretty tired afterward and get hungry quickly.” The GI uses glucose or white bread as a reference food – it has a GI score of 100. These ranges, along with some example foods, include:  low GI (less than 55) – e.g. include soy products, beans, fruit, milk, pasta, grainy bread, porridge (oats) and lentils  medium GI (55 to 70) – e.g. include orange juice, honey, basmati rice and wholemeal bread  high GI (greater than 70) –e.g. include potatoes, white bread and short- grain rice. In order to keep meals and snacks low GI follow these tips: Select low-GI foods –typically brown (wholegrain) versions of carb foods like pasta, rice and crackers, barley, rye, quinoa as well as wholegrain breakfast cereals. Non-starchy vegetables – broccoli, cabbage, lettuce, mushrooms, raw carrots, turnips Fruits – apples, avocado, berries, grapefruit, plums, peaches, tomatoes Beans & pulses –butter beans, kidney beans, chickpeas, lentils, peanuts Nuts almonds, hazelnuts, pecans, walnuts Generally, the less processed a food, the more likely it is to have a low-GI score. Avoid 'instant' or 'easy cook' foods, because these tend to be more highly processed Mella Brophy Home Economics 6th form 2024-2025 14 Daily requirements Recommended Daily allowance (RDA)/Reference intake/RI  It is recommended that 45 to 65% of daily calories should come from carbohydrates. our age, sex, medical conditions, activity level and weight goals all affect the amount that’s right for you.  Sugar: No more than 30g per day should be from sugars  Dietary Fibre 25 -30g of cellulose/dietary fibre  Associated dietary disorders:  Too much sugar/starch can lead to obesity, type 2 diabetes, dental cavities and increased risk of heart disease.  Too little cellulose/dietary fibre can lead to bowel disorders. Digestion Soluble fibre can be digested by your body. It is broken down in the colon (large bowel) by bacteria. Stools become bulky. Insoluble fibre (“gut healthy fibre”) is not digested by the body but absorbs water very effectively contributes to an increase in stool weight. Stimulates peristalsis. Glucose is oxidized to produce heat and energy. 1gram = 4Kcal energy If not used, converted to glycogen and stored in the liver and muscles as an energy reserve. Excess is converted to fat and stored under the skin as adipose tissue During diges on, water and enzymes break carbohydrate chains into monosaccharides. This process is called hydrolysis. Mouth= food is chewed into small pieces by the teeth. The salivary gland secretes saliva containing the enzyme amylase which breaks down starch to maltose. (disaccharide) Pancreas= secretes pancrea c juice containing the enzyme amylase into duodenum (the first part of the small intes ne). This con nues to break down starch into maltose. From there, the wall of the small intes ne begins to make lactase, sucrase, and maltase. These enzymes break down the sugars even further into monosaccharides or single sugars. These sugars are the ones that are finally absorbed into the small intes ne. Once they’re absorbed, they’re processed even more by the liver and stored as glycogen. Other glucose is moved through the body by the bloodstream. The hormone insulin is released from the pancreas and allows the glucose to be used as energy Mella Brophy Home Economics 6th form 2024-2025 15  Vitamin B1, B2 and Pyrodoxine are needed to metabolise (release energy) from carbohydrates. Summary of digestion Organ/gland Secre on Enzymes Substrate Product Mouth Saliva Salivary Starch Maltose (salivary amylase glands) Pancreas/ Pancrea c amylase Starch Maltose duodenum Juice Small Intes nal Maltase Maltose Glucose intes ne juice Sucrase Sucrose Glucose & fructose Lactase Lactose Glucose & galactose Mella Brophy Home Economics 6th form 2024-2025 16  Digestion of Carbohydrates food is chewed into small pieces by the teeth. The salivary gland secretes saliva containing the enzyme amylase which breaks down starch to maltose. (disaccharide) Oesophagus transports food to the stomach Intestinal Juice- enzymes -maltase, Salivary amylase sucrase, lactase is denatured by produce Monosaccharides stomach acids (glucose, fructose and galactose) are absorbed through Pancreatic amylase the villi of the continues digestion small intestine into in the small the blood stream intestine and are carried to the liver in the Anything that’s left after Hepatic portal digestive processes goes to vein. Lipids Past Exam questions the colon. It’s then broken Waste is 2024 - Section C - Question down 4 - Par by intestinal bacteria. Fiber cannot be digested by expelled from the body, absorbs water, the body. reaches the colon and is Mella Brophy Home Economics 6 form 2024-2025 17 eliminated with your stools. th