Can Lacquering by Jane Khor https://padlet.com/uu_sotong_uu/so5dcxklqvth Inner layer of can usually coated with a protective layer which known lacquers. Different type of lacquer coating has possess different functionality and application in food canning. en-us 2016-11-25 14:08:45 UTC 2025-11-07 10:15:04 UTC hello@padlet.com Canning of Food Industry uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139906611 Since 18th century, canning process has been introduced in order to preserve food in France. It is a method of preserving food in which the food contents are processed and sealed in an airtight container. Canning provides a shelf life typically ranging from one to five years, although under specific circumstances it can be much longer.]]> 2016-11-25 14:20:27 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139906611 Problem of canning uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139907803 The metal can used to pack food is usually made of tin, aluminium and steel. However, some of the food will react with the metal and cause corrosion and production of toxic substances. ]]> 2016-11-25 14:28:17 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139907803 Lacquer Coating uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139909662 A protective layer is coated on the inner surface of the metal can after heat treatment in order to protect the food, which also known as lacquer. ]]> 2016-11-25 14:41:05 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139909662 Type of lacquer uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139911517 Since the lacquer will have direct food contact with food, hence only limited number of chemical substances can be use. However, there is many variation of each type.
1. Epoxy phenolic
  • Universal gold lacquer for three piece can
  • Has good flexibility
  • High heat stability
  • Resistance to acid
  • Excellent chemical stability especially sulphide ion
2. Organosol
  • Often used over epoxy phenolic basecoat. 
  • Very good flexibility
  • Very good pack resistance
3. Phenolic
  • Very poor flexibility
  • Excellent pack resistance
  • Oustanding chemical stability especially sulphide ion
4. Arcylic
  • Good color retention
  • High resistance to heat
  • Provide internal protection as hard white coatings
5. Oleoresinous
  • Flexibility is depended on the type of resin used
  • Very limited use
  • Usually modified with addition of zinc oxide
  • prevent the blackening of food product due to the presence of sulphide.
]]> 2016-11-25 14:53:34 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139911517 Carbonated Drinks uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139914911 Soft drink are normally contains high amount of acid, in which corrosion might be happened in metal can and become a potentially serious problem.

The lacquer applied on the inner surface of the metal can is important in order to protect the can and prevent the migration of can material into food due to its high pressure processing. 

Below are the application of different type of lacquer coating used in beverage can:
1. Draw and wall ironing cans  
 (Aluminium)
  • Water-based epoxy acrylic system
2.Three-piece tinplate (Steel)
  • Epoxy phenolic basecoat with an epoxy acrylic internal spray
]]> 2016-11-25 15:20:12 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139914911 Importance Properties of Lacquering uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139918220
  • Able to withstand the conditions. 
  • Resistant to food during processing and any by-products 
  • No migration of components of the coating layer 
    • ]]>     2016-11-25 15:47:44 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139918220     Application of Lacquer uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139919937 Different type of food product requires different type of lacquers coating.]]> 2016-11-25 16:04:49 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139919937 High Sulphide Food uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139920227 Vegetables, meat, soups and fish contains high sulphide compound
    where the sulphur staining could be a problem. In order to prevent it, the metal can normally coated with zinc oxide-modified epoxy-phenolic lacquers due to
    • promotion of meat release properties
    • preventing the contents from sticking to the sides of the can
    • prevent sulphur blackening of the tinplate
    Function of zinc oxide
    • the lacquer soften during sterilisation 
    • permits the sulphur compounds to react with the zinc oxide
    • produces zinc sulphide (white in colour and harmless)
    ]]>     2016-11-25 16:08:00 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139920227     Fruit Juice uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139921097 The colour of juice plays an important role of lacquering coating of metal can.

    Clear Juice 
    • Unlacquered can bodies
    • covering liquid might juice will become cloudy or discoloured through oxidation if there is lacquer coating
    • E.g. pears, peaches, pineapples and yellow plums
    Color Juice
    • Full lacquer bodies
    • Quickly discoloured by contact with tin or iron without the lacquaring coating
    • E.g. coloured fruits that contain anthocyanin pigments (strawberry, cherries, blackberries)
    ]]>     2016-11-25 16:15:08 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139921097     Acidic Food (Tomato-Based Product) uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139921658
  • Unlacqured can bodies
  • Presence of tin is desirable because it eliminates oxygen
  • Prevent discolouration of the contents
  • Through oxidation of the tin surface in preference to oxidative degradation of the food
  • Fully lacquered cans do not allow this flavour to develop 
    • ]]>     2016-11-25 16:21:05 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139921658     Little Background uu_sotong_uu https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139922223 Written by Khor Yin Chen (Jane) who study in Universiti Sains Malaysia.
    I came from Alor Star, Kedah, a peaceful state where I love it very much. I am a passionate person, who always try to find passion on doing every little stuff, no matter I like it or I don't, as I believed "Everything happened for a reason".]]>     2016-11-25 16:27:42 UTC https://padlet.com/uu_sotong_uu/so5dcxklqvth/wish/139922223