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Description
Flashcards by Cleo Smiley, updated more than 1 year ago
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Created by Cleo Smiley
over 9 years ago
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| Question | Answer |
| what is food processing? | The conversion of raw animal and plant tissue into forms that are convenient and practical to consume. e.g Wheat flour. |
| What can processing food remove? | Substances such as: phyphate, polyphenols and oxalate which can affect nutrient utilization. |
| Advantages of food processing. | Mechanical processing, soaking, fermentation and germination/malting- can increase bio-availability of some nutrients. E.g. phytate inhibits iron, zinc, and calcium absorption. |
| what is food preservation? | Prevents food from being spoiled by the action of enzymes and micro-organisms. |
| How do enzymes affect food? | The alter texture, taste & colour. E.g. Apples browning when cut Fat/oil becoming rancid. |
| how do micro-organisms and yeast affect food? | Microorganisms and yeast cause mould to grow, due to the nutrient and water content of food. |
| Advantages of food preservation: | INCREASES: 1)safe storage of food 2) availability- out of season foodstuff. 3)availability- Transportation easier 4) shelf life and reduces production costs. |
| Definition of food preservation: | Use of specific thermal & non thermal techniques to: * Minimize the # of spoilage microbes in food. * make food safe- extended shelf life. |
| What should be maintained in food preservation? | Nutritional value Texture Flavor of food. |
| What are methods of preservation & storage? | Heating cooling reducing water content irradiation chemical preservatives novel Techniques |
| What are 2 types of heating methods? | Pasteurizing & heat sterilizing. |
| What are 2 types of cooling? | Freezing & Refrigeration. |
| What are 5 types of reducing water content? | Sugaring (Jam) Salting Pickling Drying Smoking. |
| What are 3 other types of preserving food methods? | Irradiation, chemical preservatives & Novel techniques. |
| What is pasteurization and what effect does it have on food? | Mild treatment (Temp between 80 °C-90 °C) Minimizes pathogenic microbes. Effect on food: Minor changes to nutritional & sensory characteristics of foods. Shelf life extended by a few days or weeks. |
| What are some foods that are pasteurized and how is this done? | Milk Heated for 15 sec @ 72 °C Destroys pathogenic organisms. |
| What are some public health concerns with raw/unpasteurized milk? | Banned in Scotland. In the UK 0.01% of raw milk. Associated with food borne diseases. mishandled raw milk= 3x more hospitalization than other food borne diseases. |
| What is heat sterilization? | Complete destruction of organisms Effect on food: Increases shelf life up to 6 months @ ambient temperature. |
| What is an example of food that is heat sterilized and how? | Milk -Heated for 15mins @ 12 °C -destroys all contaminating bacteria -causes flavour changes Loss of Vit c & B Vitamins. |
| What is UHT? | UHT= Ultra heat Treated/ Ultra High Temperature processing. -Higher processing temperatures for a shorter time. Shelf life @ least 6 months (No Fridge) |
| example of UHT food and how. | UHT Long life milk, juice, yogurt, wine Heated for 1 sec @ 135 °C -destroys all bacteria tastes better than sterilized more widely available- abroad. |
| What is Blanching? | Blanching= heating food to 75 °C-85 °C for 1-8 Minutes. Food heated rapidly to a pre-set temperature, held for a pre-set time , cooled rapidly to near ambient temperatures. |
| What happens in blanching? What are Nutrient losses/gains in Blanching. Examples? | It inactivates autolytic Enzymes. It is a pre-treatment before canning/freezing. There are minimal losses. Examples: Vegetables. |
| What is canning? | Food heated and sealed in an air tight container. Destroy microbes + prevent re entry 2 ways of processing: *Boiling- Water bath *Pressure canner. |
| What foods can be canned? | Vegetables, meat, pasta. |
| Are there any gains or losses in canning? | Texture + taste changes Longer shelf life Nutritional losses- Vit C Nutr Gains: Lycopene + Dietary fiber. |
| What is freezing? | Food frozen below -18 °C Domestic freezers (-6 °C to -12 °C) Preserves food for months/years if properly stored. Stored in bulk- cost effective. |
| Are there any changes in freezing? | minimal change 2 flavour + Nutrient loss Emulsions= destabilized Damage to cells by ice crystal growth |
| What is refrigeration? | House hold fridges = 2-8C T > 10 C avoided |
| Are there changes in refrigeration? | Reduces rate of biochemical + microbiological changes Extends shelf life of fresh + processed food Biochem & Physical changes during Fridge storage= loss of quality- limit shelf life |
| What is sugaring? | Creates hostile environment- water removed. Food= heated with sugar = packed in sugar |
| Changes in sugaring? | Sugar attracts water= fermentation Increased Energy content. |
| Examples of foods that are sugared. | Jam. |
| What is salting? | Addition on NACL 1 of the oldest methods of preservation Most bacteria, fungi, pathogenic organisms cannot survive in high salt environment – hypertonic nature |
| Changes in salting? | Increases sodium content of food which has health implications- High blood pressure. |
| What is pickling? | Anaerobic fermentation = produce lactic acid (Salt in water=brine) Marinating + stored in acidic solution usually vinegar (acetic acid) pH <5 |
| Changes in pickling? | Increases sodium- Health implications. |
| What is drying? | Moisture removed- heat. Moisture content too low for microbes to grow. Sun, air/wind + freeze dry UNLIMITED SHELF LIFE IN PROPER STORAGE |
| Changes in drying? | Nutrients + flavour concentrate Texture changes Chem changes to chlorophyll + carotenoid pigments. Prevented by treatment with ascorbic acid/ or SO2 VITAMIN LOSS |
| What is smoking? | Process of flavoring, cooking or preserving food by exposing to smoke from burning or smoldering plant materials e.g. wood. |
| Smoking Health concerns? | Polycyclic aromatic hydrocarbons (PAH) - production of heterocyclic amines & polycyclic aromatic hydrocarbons that can cause colon cancer |
| Changes in smoking? | Removes water (nutrients concentrate) Forms surface layer Vitamin loss Addition of flavour |
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