FOOD PROCESSING

• Food processing pre-treatments


  • Brining
  • Blanching
  • Sulfiting
• Brining


  1. Raw food is soaked in a saltwater solution

  2. Meat, fish or poultry absorbs extra liquid and salt

  3. Results in a juicier and more flavorful final dish

  4. Brine solution denatures the meat's proteins to allow the cells to retain more moisture
• Traditional brine


  1 cup of coarse salt: 1 gallon of water
• Weak brine


  30 g (iodized salt): 1 liter
• Preservation is done by other methods (e.g. drying, smoking)
• Food is treated for several minutes only in less saturated brine
• A secondary effect of such brining is the elution of soluble proteins, which form an attractive, glossy pellicle on the surface as moisture is allowed to evaporate on standing before subsequent processing continues
• 2 Methods of brining

  • Wet brine
  • Dry brine
• Wet brine


  The raw food is immersed or soaked in the brine solution
• Dry brine


  Salt is applied on the surface of the raw food, allowed to rest in the refrigerator for 24-72 hours prior to cooking
• Salt (NaCl) ionizes to sodium cation (Na+) and chloride anion (Cl-) which attracts water molecules
• These water molecules become unavailable to microorganisms
• NaCl


  Ionic bond
• H2O


  Covalent bond
• Na+ and Cl- ions pull water and flavor molecules from the food system
• Blanching


  1. Exposure of foods to boiling water temperature for a short period of time

  2. Used to lower enzymatic activity in vegetables and fruits

  3. Peroxidase is the most widely distributed heat resistant enzyme

  4. Enzymes which cause undesirable changes in fruits and vegetables are lipoxygenase, polyphenol oxidase, polygalacturonase, chlorophyllase
• Methods of blanching


  • Steam blanching
  • Hot water blanching
• Steam blanching


  Steam exposure to 60 to 90 seconds, results in higher nutrient retention than hot water blanching
• Hot water blanching


  Dipping in boiling water for 1-5 minutes
• After blanching, cooling is by means of cold air or cold-water sprays
• Effect of blanching


  • Nutrient loss (minerals, water-soluble vitamins and other water-soluble components)
  • Color and flavor (brightens color, sodium carbonate or calcium oxide added to blanch water protects chlorophyll and retains color, increase in pH may increase losses of ascorbic acid)
  • Texture (softens texture, calcium chloride added to blanch water helps maintain firmness)
• Sulfiting


  Sulfur, commonly in the form of salts, sodium metabisulfite (E223) and potassium metabisulfite (E224) is used in the food industry as a chemical preservative
• In the US, the use of sulfite in various form was Generally Regarded as Safe (GRAS)
• Reports that sulfite, particularly if inhaled as SO2, could affect some individuals suffering from asthma have led to more restricted and careful use
• Functions of sulfiting


  • Antioxidant
  • Enzyme inhibitor
  • Maillard reaction inhibitor
  • Reducing agent
  • Antimicrobial
• Pasteurization


  Most commonly used thermal preservation techniques, heat treatment with only partial destruction of pathogenic and spoilage microorganisms, requires additional processing techniques like refrigeration or freezing to render the food product stable
• The typical food that pasteurizes are high acid foods such as fruits, fruit juices with pH 4.5 and below, low acid foods need to be sterilized
• Pasteurization


  A process applied to a food product with the objective of minimizing possible health hazards emerging from microbial pathogens associated with the product while maintaining minimal chemical, physical, and organoleptic changes in the product
• Methods of heat transfer

  • Conduction
  • Convection
  • Radiation
• Conduction


  There is a direct contact between the heat source and the object being heated, thermal transfer of energy from one region to another by direct contact
• Convection


  The transfer of heat energy from heating source to the medium through intermediate phase
• Radiation


  Electromagnetic field that are releasing heat
• Mild heat treatment (60-80 °C) designed to kill the most heat-resistant vegetative pathogens and undesirable enzymes
• Pasteurization is NOT a sterilization technique, foods must be refrigerated to prevent other bacterial growth
• Blanching is a form of pasteurization
• Heating medium for pasteurization

  • Steam
  • Hot water
• The temperature-time requirement for pasteurization was fixed as 61.7 °C for 30 minutes on the basis of destruction of Mycobacterium tuberculosis, which was considered as the most heat resistant organism, later changed to 62.8 °C for 30 minutes based on the time-temperature required for destruction of Coxiella burnetii
• Types of pasteurization


  • Batch pasteurization (LTLT)
  • High Temperature Short Time (HTST) pasteurization
  • Aseptic processing
• Batch pasteurization (LTLT)


  Also known as VAT pasteurization, the vessel that uses to pasteurize the product, "per batch", mixer is an important part to accelerate the heating process, temperature 63 °C for 30 minutes
• High Temperature Short Time (HTST) pasteurization


  Also known as FLASH pasteurization, "continuous process", temperature 71.7 °C for 15 seconds (72 °C for 15 to 20 seconds), target microorganism is Coxiella burnetii