food provenance

• Controlled Sensory Analysis

  • invite people to be testers in sensory analysis
  • find a quiet area to work
  • give each tester a cup of water to cleanse their palate between each sample
  • provide small samples of food with clean spoons or fork for each sample
  • foods should be identified using code or symbols so that tasters are not influenced by brand names
  • food products should be testes carefully and results recorded accurately
• Paired Preference Tests

  • Testers asked to taste two similar products, then asked which product they prefer
• Triangle Testing

  • three samples tested but two are the same
  • aim is to find out if the tester can pick out which sample is different
• Ranking Tests

  • people asked to taste several products and award scores to decide on the order of preference
  • all samples should be coded
• Rating Tests

  • people asked to say how much they like or dislike a sensory characteristic of a product
  • use a hedonic scale to award number
  • sensory characteristic include sweetness, flavour, colour, texture
• Milk

  • fresh milk has a layer of cream on top
  • Homogenised milk is forced through tiny holes in a machine. under pressure. This breaks up the fat and disperses it, and it doesn't reform as a layer of cream
• Primary processing of food - does not significantly affect the natural values of food products

  • sorting, trimming, discarding
  • washing, wrapping
  • draining, trussing, cutting
  • heat treatment
  • milling
  • deboning, skinning, deseeding
• The Making of Flour

  Bran: the outer layer of a grain

  1. harvesting and transport to factory/mill
  2. separating from dirt, stones, pieces of metal and other pollution
  3. washing and drying to easily separate the bran
  4. milling
  5. sieving to separate the bran
• Pasteurisation: warming the milk to 72C for 15s to kill most of pathogenic bacteria

  • limited shelf life
  • little or no change to taste
  • loss of vitamin B2
  • often fortified with vitamin D
• Ultra-heat treatment (UHT): heating up the milk to 135C for 1-2s to kill all bacteria and spores, then out in an airtight container

  • allows milk to be stored for up to 6 months
  • slight change in taste, colour remains similar and little change in nutrients
• Microfiltration: pushing the milk through very fine membranes to remove bacteria and other pollutants
• Sterilisation: heating up the milk to over 110C for 30 minutes to kill bacteria and spores.

  Leads to change in colour, flavour and nutritional value of milk. During the process, milk proteins react with lactose, creating brown pigments which also affect the flavour of the milk. High temperature decreases the amount of vitamins in the milk, especially B1 and B12
• Drying: process in which milk is condensed, and then dried. The temperatures used during the process may lead to a fall in levels of vitamins B1 and B12 in the powdered milk.
• Skimmed: this is pasteurised but has has all or most of the fat removed

  Semi-skimmed: this is pasteurised but has had some of the fat removed
• Canned:

  • Evaporated: milk that has had water evaporated off; it is sweet can concentrated, homogenised and is sealed in cans and sterilised
  • Condensed: evaporated milk that hasn't been sterilised; it has added sugar and is very thick
• Secondary processing of food

  • irradiation
  • smoking
  • drying & freeze-drying
  • cooking/heating
  • fermentation
  • adding additives
• The making of pasta

  1. harvesting the cereals and transportation to the mill
  2. milling and transportation to the factory
  3. mixing flour with warm water
  4. kneading and gluten formation
  5. adding flavourings and colourants
  6. rolling and pressing
  7. pasteurisation with steam
  8. cutting pasta into chosen shape
  9. drying
  10. packaging
• The making of jam

  1. Harvesting the fruit
  2. Washing and crushing/cutting
  3. adding water and sugar
  4. Simmering
  5. Pouring into jars

  Pectin: natural gelling agent present in fruit. Released from fruit in presence of heat and acid

  Acid: may be naturally occurring in fruit or may be added to the mixture to help release the pectin
• The making of yoghurt

  Starter cultures: probiotic bacteria added to milk during yoghurt and cheese production to begin the process of fermentation

  Fermentation: changing lactose into lactic acid by adding bacteria. This changes the pH of milk and leads to protein coagulation/denaturation and thickening of the mixture

  1. milking cows and transporting the milk to the factory
  2. pasteurisation and homogenisation
  3. warming up to 42C
  4. adding starter cultures
  5. fermentation (ripening)
  6. cooling
  7. adding flavourings
  8. packaging
• The making of Cheese

  Rennet: enzyme which coagulates milk and increases curdling

  Whey: liquid by-product of cheese production

  1. milking cows and transporting the milk to the factory
  2. pasteurisation and homogenisation
  3. adding starter cultures
  4. fermentation (ripening)
  5. adding rennet
  6. cutting the curd and separating it from the whey
  7. Pressing (stacking curds on top of each other)
  8. adding salt
  9. pressing into cheese hoops
  10. ageing
• Cholesterol-lowering spreads

  Cholesterol: fatty substance necessary for correctly transporting fats around the body. Found in many animal-derived foods.

  • LDL is 'bad' because it increases cholesterol amount in blood where it can be used to build plaque in blood vessels
  • HDL is 'good' because it transports cholesterol to the liver, which can removes it excess from the body
• Cholesterol-lowering spreads

  Healthy outcomes of increased cholesterol levels and excessive fat consumption:

  in excess, cholesterol may be deposited in the blood vessels, creating atherosclerotic plaque. increases risk of hypertension, CHD, heart failure and stroke

  Some fat spreads are enriched with plant sterols and plant stanols. These substances have proven to be effective in lowering blood cholesterol level and preventing atherosclerosis
• Food Fortification

  • restore/improve nutritional value of foods
  • make food more suitable for certain groups of consumers
  • prevent diseases caused by malnutrition

  Wheat flour and bread:

  • Thiamine: to prevent beriberi disease, help release energy from food
  • Niacin: to prevent pellagra, help release energy from food
  • Calcium: to prevent rickets & osteoporosis
  • Iron: to prevent iron deficiency anaemia

  Vegetable fat spreads

  • Vitamin A: to prevent growth & eyesight issues
  • Vitamin D: to prevent rickets & osteoporosis

  Semi-skimmed and skimmed milk:

  • Vitamin A: to prevent growth & eyesight issues