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PHYSICAL AND CHEMICAL CHANGES, Pretreatments For Freezing, Chemical…

- - - - amylose reallign
        
        H bond occurs between amylose chains
        
        structure more compact ; dry n firm
- - - - modified electrostatics interaction of tertiary & quartenary structure of protein
      - fish
        
        chemical b/down of TMAO
        – DMA – Formaldehyde (FA)
        
        loss WHC, cottony, spongy texture of fish after thawing
- - - - toughening
      - leathery
      - shriveling
    - - oxidation of myoglobin
- - - - high starch
        
        high MW component
        
        high Tg
      - unmatured veg
        
        high sugar
        
        low MW component
        
        lower Tg
        
        significance
        
        foods more stable
        
        less prone to deterioration
        
        small water mobility
        
        Decrease rate of molecular diffusion
- - - - remove cellular air
        
        Affects texture, flav, color, & nut
        Q by inactivating enzyme
- - - - protective coating from
        
        dehydration & oxidation
- - - - acts as template for ice formation
        
        salmon, egg white protein, cornstarch gel
        
        Elevates nucleation T
        
        reduces freezing time
- - - - degradation of esters
        
        less aroma & +off flavor
    - - FA react with protein
        
        configuration changes
        
        change flavour
    - - off flavor
  - - - disruption of plant/animal tissue
      - Affected by freezing & thawing (large ice crystals
- - - - indication of shelf life
        
        Increase in veg during storage
        
        acet. oxidized into ethanol- off odors
  - - - Lipid hydrolysis – FFA- oxidations