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Capabilities
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SPX has a number of proven process solutions which cover many of the requirements of the modern jam producer:
However, there are many variations on these basic processes and specialised systems can be designed to meet individual requirements. |
Particulate jam products requiring evaporation
This process is used for the automated manufacture of high quality jams containing whole or part fruit by means of low temperature evaporation. It is suitable for a wide range of dietetic jams, yogfruit and pie fillings. Ingredients are metered or weighed into the pre-mix vessel, which is jacketed to pre-heat the mix and dissolve the sugar.
After mixing, to avoid product damage through pumping, the pre-mix is drawn by vacuum into the SPX vacuum cooking vessel. Zoned heating panels provide efficient heating and avoid overheating of variable batch sizes. A low-speed scraper agitator enhances heat transfer and avoids burn on to hot surfaces. Rapid vacuum evaporation takes place at a temperature of approximately 65°C, and the vapour is separated in a simple cyclone with any product carry-over returning by gravity to the vessel.
Product is transferred using filtered air pressure to the buffer tank. From there, it is gently pumped to an APV scraped-surface heat exchanger prior to filling. Heat treatment is necessary to avoid spoilage problems due to the low temperature treatment of the fruit during evaporation. Rapid heating takes place at 90°-100°C under pressure, thereby avoiding any loss of volatiles. This is immediately followed by rapid cooling to the desired filling temperature.
This is a very flexible process for the manufacture of high quality jams. It will provide product with a good colour, flavour and particle integrity. The basic plant can also be used during the fruit season to sterilise fruit pulp or fruit in syrup prior to aseptic storage in suitable containers for later use.
Particulate jam products not requiring evaporation
This process is used for the continuous production of jams, where minimal or no evaporation is required. Ingredients are metered or weighed into an APV horizontal food blender, which is jacketed to pre-heat the mix and dissolve the sugar. The horizontal agitator in this vessel produces good heating characteristics as well as rapid and gentle mixing of the ingredients.
Two blenders are provided so that as one feeds forward, the other is used to prepare the next batch of product, giving a continuous process.
The pre-mix is pumped to the de-aeration unit where air is removed under vacuum. Some minor moisture loss may also occur at this stage. The de-aerated mix is pumped to an APV scraped-surface heat exchanger where it is heated to pasteurising/sterilising temperature (typically 90°-95°C) using indirect steam heating and then cooled.
After cooling it is possible to add, in line, minor ingredients such as citric acid solution, colour and flavour. This avoids thermal damage and volatile loss which can occur if these ingredients are added earlier in the process. Finally, product enters a buffer storage vessel before going through a final cooling stage immediately prior to filling.
This non-evaporative process produces excellent quality jams with large particles and minimal thermal damage. It may also be readily adapted for the manufacture of pie fillings and yogfruit.
Non-particulate jam products
This process requires minimum energy levels to produce very high quality non-particulate jam with high retention of volatile flavour components. Ingredients are metered into one of the two pre-mix vessels, operating on a flip-flop basis. The mix is pasteurised in an APV Paraflow plate pre-heater before passing to the APV plate evaporator. The pre-mix is rapidly evaporated, under vacuum as a thin film, to the desired total solids level. The boiling temperature is typically 65°C. By fitting the plate evaporator with a thermocompressor, it is possible to reduce steam consumption to approximately half that required for a batch processing plant.
Concentrated jam is pumped directly to the filler for hot filling, or cooled in either an APV scraped-surface heat exchanger or an APV Paraflow plate cooler, depending on product viscosity. Acid and flavour dosing should take place after evaporation to avoid losing expensive volatiles in the evaporation process. With continuous monitoring of pH, very accurate control of the jam set can be maintained. If sulphited pulp is used, an APV de-sulphiting column can be installed between the pre-heater and the plate evaporator.
This process minimises thermal treatment, has very low energy requirements, and produces superb quality non-particulate jams. It is ideal for producing very high solids jams for use in the biscuit and cake industry, as well as portion-pack jams and jellies. It has al
