Method in hot filling of foods in a packaging container, as well as an apparatus therefor
A method involving the hot fill of foods in packaging containers constructed from a paperboard laminate comprises the food being filled in the packaging container with at least one component at a temperature of at least 80°, but below 100°, whereafter the packaging containers are closed and sealed and the packaging containers with their food contents are thereafter held hot during a predetermined period of time by contact with a heat holding medium at a temperature of at least 80°, but below 100°. The heat holding medium is present substantially in gas and/or vapour phase. An apparatus involving the hot fill of foods is also disclosed.
1. A method in hot fill of foods in packaging containers constructed from a paperboard laminate, comprising hot filling said food in said packaging containers with at least one component thereof at a temperature of at least 80° C. but below 100° C., thereafter closing and sealing the packaging containers, and thereafter heat holding the packaging containers with their food contents during a predetermined period of time by contact with a heat holding medium at a temperature of at least 80° C. but below 100° C., wherein said heat holding medium is substantially present in gas and/or vapour phase.
2. The method as claimed in claim 1 , wherein said heat holding medium is substantially free of liquid phase.
3. The method as claimed in claim 1 wherein said heat holding medium comprises hot air.
4. The method as claimed in claim 1 , wherein a temperature of the packaging containers with their food contents is at most permitted to fall 15° C. between said hot filling and said heat holding.
5. The method as claimed in claim 4 , wherein the temperature of the packaging containers with their food contents is raised to at least 80° C. but below 100° C. in a heating stage which precedes said heat holding, the heating stage also being carried out by contact with said heat holding medium at temperature of at least 80° C. but below 100° C.
6. The method as claimed in claim 1 , wherein said heat holding is maintained during a period of time of up to 30 minutes.
7. The method as claimed in claim 1 , wherein said heat holding is carried out in a continuous heat holding tunnel.
8. The method as claimed in claim 1 , wherein said heat holding is carried out batchwise.
9. The method as claimed in claim 1 , further comprising cooling the packaging containers and their food contents following the heat holding to a temperature below 50° C.
10. The method as claimed in claim 1 , wherein said food has a pH of below 4.6.
11. The method as claimed in claim 1 , wherein said paperboard laminate is coated with inner and outer coatings of a polyethylene based polymer, and includes a gas barrier layer.
12. The method as claimed in claim 1 , wherein the heat holding medium comprises hot air with an additional heat input comprised of at least one of steam and/or radiation heat.
13. The method as claimed in claim 1 , wherein a temperature of the packaging containers with their food contents is at most permitted to fall 5° C. between the hot fill and the heat holding.
14. The method as claimed in claim 1 , wherein said heat holding is maintained during a period of time from 10 minutes and up to 30 minutes.
15. The method as claimed in claim 1 , wherein said heat holding is followed by a cooling stage in which the packaging containers and their food contents are cooled by contact with cold water to a temperature below 40° C.
16. The method as claimed in claim 1 , wherein said paperboard laminate is coated with inner and outer coatings of a low density polyethylene, and includes a gas barrier layer.
17. An apparatus used in hot fill of foods in packaging containers constructed from a paperboard laminate, in connection with which apparatus said food is filled into said packaging containers with at least one component thereof at a temperature of at least 80° C. but below 100° C., whereafter the packaging containers are closed and sealed and the packaging containers with their food contents are thereafter subjected to heat holding during a predetermined period of time by contact with a heat holding medium at a temperature of at least 80° C. but below 100° C., wherein said apparatus comprises means in order, during the heat holding, for supplying and maintaining said heat holding medium substantially in gas and/or vapour phase.
18. The apparatus as claimed in claim 17 , further comprising at least one nozzle for supplying said head holding medium substantially in gas/or vapour phase.
19. The apparatus as claimed in claim 18 , wherein the apparatus is an oven for batchwise heat holding.
20. The apparatus as claimed in claim 17 , further comprising means for supplying said heat holding medium as hot air.
21. The apparatus as claimed in claim 20 , wherein the apparatus is a continuous tunnel for heat holding, including at least one endless conveyor belt for transporting the packaging containers.
22. The apparatus as claimed in claim 20 , wherein the apparatus is a continuous tunnel for heat holding, comprising a through-going path for carriages filled with the packaging containers.
23. The apparatus as claimed in claim 20 , wherein the apparatus comprises a helical path operative to move the packaging containers substantially in a helix upwards and/or downwards during the heat holding.
24. The apparatus as claimed in claim 17 , further comprising means for supplying said heat holding medium as hot air with a steam admixture and/or radiation heat as an additional heat input.