Food Tech Yearly Notes PDF

FOOD TECH YEARLY NOTES Food selection and availability Staple foods must be: - Readily available - Provide major source of energy - Most important source of protein - Plant or animal origin - Inexpensive and plentiful Plant staple foods...

FOOD TECH YEARLY NOTES Food selection and availability Staple foods must be: - Readily available - Provide major source of energy - Most important source of protein - Plant or animal origin - Inexpensive and plentiful Plant staple foods Meat/ animal staple foods - Potato - Beef - Rice - Lamb - Wheat - Chicken - Corn - Barramundi - Salmon Historical changes to availability of food: Global migration of cultural groups to Australia: - Each arrival of large groups resulted in an increase to food availability - Each group introduced and prepared familiar food to their homelands Timeline: 1788 First fleet arrived, introducing British foods like flour, biscuit, salted meats, peas and rice. 1830s German immigrants arrived in Australia, establishing vineyards. 1850s The gold rush attracts global migration to Australia. 1880s Italians migrate to Australia to work in sugar cane fields 1920s American cereal factories eg Kelloggs 1940s WW2 American troops introduced coca  cola, hamburgers and processed foods. 1960s-1970s American fast food chains brought to Australia like Mcdonalds, KFC, pizza hut. Current In current society Australia has a diverse range of cuisines from across the world. Chinese migrants Worked in various roles across Queensland and NSW; introduced new vegetables and cooking methods. Scandinavian migrants Settled in Victoria; founded dairy industry and introduced things like cheesecake. Greek migrants Established in Victoria; Introduced vine leaves, feta cheese and filo pastry. American migrants Introduced farming, cooking skills and food chains later to settlement. Foods native to Australia - In 1788, prior to European settlement, Aboriginal had a native nutritious food supply and made use of hunting methods. - Food source was from the land; animals and plants - Their food source is known as bush tucker referring to flora, fauna and fungi utlised for culinary purposes. Technological developments influence on food availability - Advancements in food storage resulting in improvements to food quality, availability and safety - Transport can lead to wider accessibility - Maintain constant food supply - Consume foods produced globally Marketplace practices: Where customers purchase their food is a significant factor related to food selection - International marketplaces sell their food globally to boost their economy. Advantages Disadvantages  - Wide variety - Dependent on working technology - Time saving - Increase in artificial foods Factors affecting food selection 1. Social 2. Economic 3. Physcological 4. Physiological Food quality Food preservation: The aim of preservation is to prevent spoilage as a result of growth of microorganisms and breakdown of food enzymes. Preservation allows - For surplus food can be stored to be used in times of shortage - Enjoy seasonal fruits all year round - Food to be transported long distances - To be stored at home for long periods of time without going off Preservation methods Name Type of Definition Disadvantages/ preservation Advantages Canning Heat Heating a can to a High in sodium and temperature of 120oc sugar, loss of nutrients. can sterilise contents and kill spores. Pasteurisation Heat Rapidly heating milk The heating destroys to 72oc for 15 enzymes in milk seconds. otherwise helps the body assimilate nutrients especially calcium. Sugar Chemical High concentrations of High sugar content sugar effectively draws out any Loss of vitamins through microbes in the food the heating process. and dehydrates them. Salting/ curling Chemical Coating or placing Alters taste significantly, food in salt / brine dries out product and  (salt solution) reduces high sodium. moisture content. Vinegar Chemical The acidic High salt content environment of vinegar reduces enzymes and food spoilage microbes. Smoking Chemical Exposing food to Often not fully cooked, smoke from burning or the process can release smouldering wood carcinogens such as prevents bacterial nitrates in food which growth. can be harmful. Drying Moisture removal The drying method Calorie rich and high in inhibits the growth of sugar, does not remove bacteria by removing toxins that were already water contents- present in the pre dried bacteria can’t grow product. without moisture. Accelerated Moisture removal Food is rapidly frozen Lightweight and easy to freeze drying and subjected to transport. Retain radiant heat from a nutritional value and vacuum removing all taste. Can last for moisture through months- years and sublimation. unlike dehydrated foods they can quickly rehydrate. Can be a costly process due to specialised equipment. Freezing Temperature Storing food at -18oc Can damage cell control for a maximum of 3 structure, when freezing months. the microbes don’t die it just stunts its growth (slows it down). Vacuum Vacuum packing Storing the food in a There are forms of packing container/ bottle bacteria that prefer low where oxygen has oxygen environments been removed. and grow well in vacuum packed food. Food nears to be clean and uncontaminated prior to sealing to prevent breeding for bad bacteria such as botulism. Modified Modified This method consists This method only atmosphere atmosphere of putting gas in the prevents aerobic  packaging packaging (MAP) packaging. The spoilage bacteria. (MAP) atmosphere inside Bacteria such as listeria maintains colour and and clostridium can only spoilage delays. be controlled by the control of PH, moisture, temperature control and storage time. Food Hygiene Food hygiene: Utilising the appropriate equipment, suitable techniques and using safe hygienic practices whilst handling food. Low risk foods: Bacteria can’t multiple on dry High risk foods: Foods that support the food or food that contains high concentrations of multiplication of harmful bacteria. Foods are sugar, salt, acidic and other preservatives. typically high in protein and moist. - Cereals - Chicken - Dried pasta - Meat - Biscuits - Milk - Crisps - Cream - Jam - Soups - Canned food - Shellfish - Eggs - Cooked rice Direct contact: Direct contact is when bacteria is carried between one food to another when they touch/ drip. An example is raw meat touching cooked meat. Indirect contact/ cross contamination: The transfer of bacteria from a contaminated food (usually raw) to objects used for ready to eat foods. Examples include cutlery, hands, chopping boards and work surfaces. Danger zone for bacteria growth: - The temperature range for multiplication of most foodborne bacteria is 5c to 60c - Most rapid multiplication = 20c to 50c - Bacteria die slowly after 61c to 74c - Bacteria die quickly above 75c Type Sources Onset Symptoms Duration Destroying  period Salmonella -Raw eggs 6-72 -Abdominal 1 to 7 days Heat -Raw hours pain poultry -diarrhoea -Raw meat -Vomiting -Dairy -Fever products Staphylococcus -Meat 1 to 8 -Abdominal 1-2 days None Aureus -Dairy hours pain -Egg -Vomiting -Poultry -Diarrhoea Clostridium -Poorly 8-24 -Abdominal 12 to 24 Heating Perfringens packed or hours pain hours leftovers stocked -Diarrhoea above 74 meat and hours and vegetables not leaving covered in food out soil longer than 2 hours. E Coli -Sewage 1-8 -Nausea 1-2 days Heating -soft cheese hours -Abdominal above 71 -minced pain degrees beef and Diarrhoea chicken Listeria- -Dairy 1-70 -Flu When Dangerous to products days -meningitis temperature pregnant women, -Raw meat -septicemia exceeds 91 diabetics and and fish degrees asthmatics -cooked poultry Prevention In order to prevent food poisoning you need to stop bacteria from growing and multiplying on food. You can also prevent it by destroying existing bacteria typically through heat. In order to stop bacteria from growing you need to - Cover food - Handle raw and cooked foods separately - Keep animals and insects away - Dispose of rubbish careful (keep bins covered) - Maintain hygienic clean practices Functional properties Factors that affect functional properties of food: Oxygen When oxygen interacts with food it can cause drying and browning- Easy way to prevent it is airtight containers or plastic wrap. Some recipes require oxygen e.g to make a product lighter and have more volume to rise (airy whipped). Temperature Temperature can create significant changes in food for example heating/ cooking meat for it to go from red to brown. Acidity (level of PH) The acidity of foods is measured through the PH scale with below 7 being acidic and above being alkaline. Water has a neutral PH of 7 however most foods are between 2-8. Acidic foods include citric acid in lemons, acetic acid in vinegar and lactic acid in milk. Alkalis aren’t common in food however bicarbonate soda contains alkalis so when combined with acid it creates carbon dioxide so it can rise. Agitation Agitation methods include beating, whisking and folding ingredients. For example in pavlova, egg whites are beaten to stretch egg protein and form a firm structure with high peaks, then corn flour is gently folded in to not deflate the structure of the egg whites. Enzymes Enzymes main function is to catalyse (speed up) chemical reactions. They are responsible for both ripening and decomposing fruits and vegetables. They can also be used to tenderise foods. Addings other ingredients Combining ingredients can change the end result of a food. Sugar and salt are examples of key foods that serve particular functions in foods. Timing is also important when adding ingredients to succeed. For example if you add in the sugar too early in pavlova the egg whites will become unstable and it will lose its structure. Protein: Type Meaning Example Protein structure Proteins form part of the The shape of protein can structure in a cell which are affect its ability to denature, made up of small units coagulate, gel, foam or called amino acids. Due to brown. proteins being long they rather make a globe shape or fibrous shape (elongated). Denaturation Denaturation is a process This separation is caused that occurs when the by 5 factors: structure of protein breaks Temperature- Cooking a apart. When bonds are steak broken the strands separate Agitation- whisking egg or unwind. whites Acidity- Making sour cream and yoghurt Enzymes- Marinating meats Salt- Cooking eggs with salt water Coagulation When a protein separates If coagulation occurs for too from other nutrients from a long (overcoagulation) the liquid to a solid. This occurs protein shrinks and after denaturation- the toughens the forcing liquids denatured proteins start to out from inside proteins. rejoin and form a different structure and create a solid mass. Gelatation (can occur in Gelation is the process that For gels to form these must protein and occurs after coagulation be present: carbohydrates) when gel forms. This happens when tiny droplets - Heat of liquid become trapped - Acids within coagulated proteins - Enzymes which form soft elastic foods (custard and cheese). Foaming The process of air being Aeration in egg whites can beaten into a liquid to create be affected by these foam. An example is egg factors: whites in meringues and Temperature- Better results cakes. at room temperature Acids- Small amounts (cream of tartar lengthens process but provides stability) Agitation- Faster beating and finer blades will produce greater and finer foam.  Adding other ingredients- Egg yolk prevents foaming, water increases volume but decreases stability and sugar added at the end makes foam shinier and more stable. Browning- Oxidation The exposure of air to turn The process involves: (oxygen) meat from red to brown. - Myoglobin being Various factors can increase exposed to air the process time like heat, (leaving meat freezing temperatures, uncovered). certain metals and bacteria. - Oxygen changes myoglobin to produce oxyglobin. - The oxyglobin turns into metmyoglobin which is brown. Browning- Non- enzymic This form of browning - Myoglobin (Applying heat to meat involves the use of applying denatures, turning surface) heat to turn meat from red to meat from pink to brown (cooking). There is no brown to grey oxygen factor involved. - The process begins on the outside and transfer to inside - When the meat reaches 82C it is considered well done. Browning- Maillard The application of dry heat Ways to achieve: reaction to foods containing protein - Baking (Heating without touching) and sugar. It is typically - Roasting characterised by foods - Grilling creating a yellow to brown - Barbequing crust eg bread, roast meat, - Frying cake and fried chips. Moist heat methods (no crisp crust) - Steaming - Boiling Carbohydrates: The 3 types of carbohydrates are polysaccharides, disaccharides and monosaccharides Functional properties: Type Meaning Factors affecting Gelatinisation The ability of starch to thicken Temperature- Requires mixtures in the presence of heat. warm moist conditions, Common thickening agents are cannot thicken in cold water. plain wheat flour, corn flour and arrowroot. Agitation- Essential to create a smooth gel formula. If not used the starch granules will create a lumpy formula. Other ingredients and PH- Sugar and acids create a significant effect as sugar can absorb more water making mixture less stable. Things like lemon juice also need to be added after the formula is thickened and boiled. Dextrinisation The process when starch is Can be caused by: broken down into dextrins e.g - Exposure to dry heat bread being toasted. Starch can - Action of acids undergo a partial breakdown into - Action of certain shorter glucose chains (dextrins). enzymes Crystallisation The ability of sugar to dissolve and Temperature- Higher create crystals. Used in temperatures cause confectionery such as toffee, molecules to move faster fudge and caramel. The process and collide more frequently ( consists of the sugar being harder solution) dissolved in liquid, heat causing evaporation and allowing mixture Acid- Adding acids such as to cool and sugar reforms cream or vinegar prevents (crystallises). large crystals being formed (smoother texture) Agitation- Stirring solution encourages crystals to develop. Best to stir after solution after it has been boiled to prevent grainy texture. Other ingredients- Monosaccharides being included (honey, acidic ingredients) help to achieve a smoother texture.  Caramelisation Sucrose melts at 186C so when - Occurs without water temperature exceeds, the acid as it evaporates prior forms and molten sugars turn light to caramelisation brown. (caramelises) - Caramelised sugar adds a distinctive flavour to foods like cake and milk. Nutrition There are 6 essential nutrients that your body requires for vital functions including digestion, absorbing food, breathing, pumping/ filtering blood throughout the body, growing and repairing tissue and defending against infection. Nutrients cannot be produced in the body they need to come from food. Macronutrients: Provide energy. Consists of protein, lipids and carbohydrates. Micronutrients: Gives the body a stronger immune system. Includes vitamins, minerals and trace elements. Macronutrients Micronutrients - Protein - Vitamins - Lipids - Minerals - Carbohydrates The sixth essential nutrient is water which is required to survive. Structure and composition Nutrient Structure Composition Carbohydrates 3 groups: Composed of carbon, - Monosaccharides hydrogen and oxygen atoms - Disaccharides in the ratio 1:2:1 - Polysaccharides Protein Protein is made up of amino Composed Carbon,  linked by peptide bonds. hydrogen, oxygen and nitrogen. Lipids (fats) Made up of fatty acids Composed of carbon, attached by a glycerol hydrogen and oxygen. Other molecule. elements are sulphur, nitrogen and phosphorus. Water Composed of 2 hydrogen atoms and 1 oxygen atom. Vitamins Dependent on what vitamin Dependent on what vitamin Minerals Dependent on what mineral Dependent on what mineral Functional properties Nutrient Functional properties Protein - Provides structure for cells, tissue and organs - Serves as enzymes, hormones and antibodies; regulating bodily functions - Acts as a source of energy when carbohydrates and fats aren’t available. Carbohydrates - Provides energy for physical activity and brain function - Source of dietary fibre, aiding digestion - Quick source of energy specifically simple forms such as glucose Lipids - Concentrated source of energy; more than twice the energy of carbohydrates and protein. - Insulates body and vital organs - Aid the absorption for fat soluble vitamins (A,D,E,K) vitamins - Acts as coenzymes, facilitating enzymatic reactions within the body - Crucial role in energy metabolism, immune function and tissue repair - Maintain healthy skin, eyes and bones  Minerals - Promotes good muscle, bone and nerve function and oxygen transport - Acts as a cofactor for enzymatic reactions in the body. - Helps maintain fluid and acid-base balance. Water - Vital for hydration, nutrient transportation, waste removal and temperature control. - Facilitates chemical reactions in the body - Main PH levels and electrolyte balance. Nutrient interrelationships Nutrient interrelationships occur when one nutrient relies on another nutrient to carry out a particular task eg being absorbed into the body. Iron and vitamin C: - Vitamin C assists the body to absorb iron due to its acidic composition - Both nutrients work together to create red blood cells. Iron is crucial for haemoglobin whilst vitamin C is good for blood vessels. - Many high fibre and dairy foods can block iron absorption Iron and fibre: - Fibre reduces the uptake of iron by absorbing iron from the digestive tract therefore allowing absorption through the abdominal wall. - Excess fibre foods (leafy greens and fruit) can interfere with iron absorption, preventing its uptake into the bloodstream. Calcium, phosphorus, vitamin D and lactose: - Improve the body's uptake of calcium - Vitamin D controls calcium and phosphorus levels in the blood and aids calcium absorption. - Lactose (disaccharide) improves calcium transfer through the intestinal wall and into the blood. Calcium and fibre: - Insoluble fibre can’t be processed by the digestive system - Fibre reduces uptake of calcium through the digestive tract to be able to absorb in intestinal wall Folate and vitamin B12 (cobalamin) - Both are required to produce protein cells particularly needed to produce red blood cells. Sodium and potassium: - Both rely on each other to properly function e.g maintaining osmotic pressure in cells, muscle concentration and relaxation, nerve impulse transmission (sodium and potassium levels need to be the EXACT same) Digestion: The chemical and mechanical breakdown of food into its smaller nutritional components. Absorption: The movement of these components from the gut into the blood and lymphatic systems of the body. Metabolism: This refers to all the chemical processes that utilise nutrients to create other substances. When nutrients are broken down into their Catabolism components; typically for energy or to create other substances. For example starvation causes muscles to break down in order to supply energy.  Occurs when new molecules are produced Anabolism from substances released by catabolism. For example when recovering from an injury anabolism creates new protein to repair the damaged tissue. Nutrient requirements throughout the life cycle Pregnancy and Lactation: It is important for pregnant women to maintain a healthy diet in order for the foetus to grow and develop. If the woman is lacking any nutrients the foetus uses her body stores, ultimately poorly affecting her own health. If her body stores are insignificant it can lead to the baby having a low birth weight or birth defects. Pregnant women: Protein - Growth of foetus and placenta - The uterus, breast and blood supply increase in size which requires protein. Energy - Pregnant women experience increases in their BMR (basal metabolic rate) likely resulting an increase in energy intake Vitamins - Vitamin C is used for forming strong healthy tissue in the foetus - Vitamin C also assists with iron absorption - Folate B12 are both involved in forming red blood cells Minerals - Minerals are important due to a lack of iron (anaemia is very common) as they require double the amount of iron to form red blood cells. Nutritional requirements lactation: - In order for women to properly produce breast milk it requires the mother’s body to have a rich energy source - It is also essential for Women to consume complete protein to maintain muscle mass - Vitamin C is a key antioxidant in milk - B group vitamins aids development and growth in the mother’s body to produce an adequate supply of breast milk - Iron is used to make haemoglobin that carries oxygen through red blood cells  - Calcium compensates for the loss in bone density from producing milk Adolescence - It is essential adolescence consumes energy due to the growth of bones, muscles, tissues and increase in blood volume. - Protein and B group is required to build new body tissue such as muscles - Minerals such as calcium, phosphorus and iron are required to lengthen bones Adults: -