IMG 405 Food Packaging Assignment by Lim yi ting https://padlet.com/limyiting94/g5hqudy4vi5i The right lacquer will contribute to the shelf life quality of a can food. Discuss the importance of lacquering process, their class/ types and their application. en-us 2016-11-11 07:17:24 UTC 2026-01-27 22:31:00 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Drinkingmed.png Production of 2 piece cans limyiting94 https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136940944 2016-11-11 07:40:36 UTC https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136940944 3.Type of Lacquer limyiting94 https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136940988
Epoxy-phenolic. The most widely used at present.The high molecular
weight epoxy resin is cross-linked with phenolic resole resin.It is resistant to acids, with good flexibility, adhesion characteristics, and high heat stability. It covers a large variety of applications, such as fruits, fruit juices, vegetables, soup, meats, and marinated fish.


Acrylic. It is used when a good color retention and high resistance to heat are required. It is Formerly used only for exteriors. They are now provide internal protection as hard white coatings with an attractive ceramic and stain-free appearance.


Phenolic. It is the self cross-linked of phenolic resin. It is chemically stability and has low permeability, especially against sulfide ions. It has poor flexibility but film quality is weight dependent. It is used to coat the cans containing meat and fish products.


Vinyl. It has good adhesion and flexibility. It cannot resist sterilization at high temperatures. It is free from odor and flavor. It can be functioned as second lacquer layer for beer, wine and carbonated beverages and for cakes, sweets, dry foods and pharmaceutical products.


Oleoresinous. It is made of naturally occurring oil with synthetic modification. It is usually modified with the addition of zinc oxide in order to prevent blackening of product due to reaction of thins with sulfur compounds. Its applications can be subdivided to two groups : “R” or fruit enamels – protect the natural pigment of highly colored fruits such as dark berries, red beats and red cabbage. “C” enamels – prevent the discoloration of foods containing proteins such as corn, peas, poultry and seafoods.

]]> 2016-11-11 07:40:58 UTC https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136940988 Production of 3 piece cans limyiting94 https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136952466 2016-11-11 09:11:06 UTC https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136952466 1.What is lacquer? And what are its functions? limyiting94 https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136956417 Lacquer is an internal coating or the food contact surface coating for metal-based packaging.It provides protection of the food from the metal. For example, lacquer prevent discolouration of
dark-coloured fruits, such as plums and strawberries due to metal contact. Besides that, lacquer also protects the metal by preventing chemical reaction between food and metal. Acidic soft drinks is a good example which may corrode the uncoated metal.]]> 2016-11-11 09:35:33 UTC https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136956417 2.How to apply lacquer? limyiting94 https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136988780 Lacquer can be applied to the surface by roller coating or spraying before undergoing a cure schedule (stoving or baking).]]> 2016-11-11 12:54:30 UTC https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136988780 4.Precautions using lacquer limyiting94 https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136993616 *The lacquer itself must be suitable chemically.
*The minimum optimum film weight should be determined.
*There should be minimum delay between extruding and annealing or degreasing.
* There should be no delay between final rinse and drying.
*The cans should be free from deep extrusion lines and torn metal.
*Cross scoring should be absent.
*There should be minimum delay between annealing or degreasing and internal lacquering.]]> 2016-11-11 13:24:22 UTC https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136993616 5. Lacquer for canned food limyiting94 https://padlet.com/limyiting94/g5hqudy4vi5i/wish/136998058 The most demanding foods to be canned are meat, fish, high-sulphur vegetables (peas and sweet corn), highly acidic foods (sauerkraut and rhubarb) and highly coloured foods (red fruits and curry). 

Canned food will undergo retort. Hence, the lecquer must withstand the high temperature and must be resistant to the food contents or by-products such as hydrogen sulphide in the can during processing . There should be also no migration of components of lacquer to the food to increase shelf life of the food.

Some food such as vegetables, meat, soups and fish are slightly corrosive which will produce sulphur compounds which will lead to sulphur staining in the metal can. Hence, the ends of cans are coated with zinc oxide-modified epoxy phenolic lacquers to absorb odorous sulphides liberated by food during processing. The reaction of sulphur compound with zinc oxide produces zinc sulphide, which is white in colour and harmless. Thus, there is no extra sulphur compound to react with the metal to cause staining. Hence,  it extents the shelf life of the food.

Besides that, the lacquer can be the releasing agent too. For example, epoxy phenolics lacquers promotes the meat release properties in a can. With the aids of waxes and silicone, the solid meat slides more easily from the can by preventing the contents from sticking to the sides of the can. This improves the quality in terms of convenience of the canned food product. 

For coloured fruits such as raspberries, blackberries and black cherries consist of anthocyanin pigments which are quickly discoloured if contact with tin or iron. Thus, these fruits must be canned in totally lacquered can to prevent oxidation of pigments.




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