Premium quality tomato powder that’s less prone to syneresis
By Jesper Oldrup
The quality of tomato powder depends on the drying equipment. That’s the conclusion of Jesper Oldrup from the Food & Dairy Division of GEA Niro in his presentation to the Food Ingredients Exhibition at the Excel exhibition centre in London’s docklands recently. The FILTERMAT™ dryer from GEA Niro has the ability to handle this hygroscopic product, without the use of additives and produce a superior product when compared with that from conventional spray dryers. The process uses up to 45% less energy and the powder is less prone to syneresis when reconstituted.
In his presentation Jesper explained that tomato powder had many applications in the food industry for use in soups, baby foods, snack foods and as flavourings. The product was, however, difficult to dry efficiently because of its hygroscopic nature that causes it to clog dryers if not used with the addition of anti-caking chemicals. The FILTERMAT™ dryer from GEA Niro solves this problem, producing a premium quality agglomerated product and using significantly less energy than traditional tomato dryers.
Jesper explained the process of tomato powder manufacture from the chopping of the fresh fruit, through heat treating, pulping, the removal of the seeds and skins, concentration and sterilization. However he said that the choice of technology for drying determined the quality of the final product. This quality is dependent on particle size, holding time within the dryer and temperature influences. It is characterised by the hygrosopicity, its ease of dispersal, the level of dust, colour, taste, the texture of the reconstituted paste and the amount and type of additives used in its production.
Simple Spray Dryer A simple spray dryer, for example, requires the tomato paste feed to be mixed with Maltodextrin. This easily digestible carbohydrate made from natural corn starch helps to prevent caking but also increases the bulk of the final product and detracts from the flavour. Drying in a simple spray dryer is the least expensive option however it produces a fine powder that is not easy to reconstitute with water and can contain high levels of dust.
Tomato Spray Dryer
The tomato spray dryer, however combines a spray dryer with a VIBRO-FLUIDIZER™ (fluid bed). The particles remain sticky within the dryer as Maltodextrin is not added. But as the chamber walls are cooled the deposited sticky powder hardens and slidesd down into a lump breaker. However, the VIBRO-FLUIDIZER™ completes the drying process and produces an agglomerated product that can be reconstituted easily. Maltodextrin is, however, sometimes added to improve storage characteristics.
FILTERMAT™ Spray Dryer The FILTERMAT™ combines a nozzle spray drier with a built-in conveyor belt. The liquid feed concentrate is sprayed downwards with the drying air in the first stage. The part-dried powder spends several minutes on the belt allowing it to stabilise and dry slowly and cool properly before discharge. This produces a product of exceptionally high quality with large agglomerated particles without dust-creating fines. No additives are required.
Tests show that both the tomato spray dryer and the FILTERMAT™ produce high quality powder however the FILTERMAT™ does so at much lower outlet air temperatures thereby using much less energy and avoiding any risk of heat damage to the product. The outlet air temperature from the FILTERMAT™ is just 90°C compared with 140°C for the tomato dryer; steam consumption is over 40% lower (2,300kg/h against 1,300kg/h); chilled water usage is down too from 15m3/h to just 12m3/h; and power usage is down b
y a massive 60% (just 125kW from 315kW). Although the purchase price of the FILTERMAT™ is approx 1.6 times higher this premium quality product and power savings soon provide a return on the additional investment.
In addition to the financial savings and quality benefits tomato powder produced on the FILTERMAT™ has shown significantly less tendency to synerate (i.e. for the liquid elem ent to separate from the paste). The level of syneresis is dependent on the quality of the paste, browning reactions in the dryer, pectin degradation, cellulose degradation and the presence of additives. The drying conditions in the FILTERMAT™ produce a powder that, when tested using a standard ‘Soup Application Test’* showed a marked difference in syneresis, when compared with other drying techniques, both for hot break and cold break processing.
* For the ‘Soup Application Test’ 8g of powder are mixed with 120g of boiling water, stirred, left to stand for 5 minutes, then 10ml is poured onto a plate. The level of syneresis can be clearly observed.
Further editorial information from: Steve Jordan
The Words Workshop
26 Swanwick Lane
Milton Keynes
MK10 9LD
Tel:
+44 1908 695500 Fax: +44 1908 690099
Email:
steve@thewordsworkshop.co.uk
All business enquiries to:
Sten Warburg
GEA Niro Food & Dairy Division
Gladsaxevej 305
DK-2860 Soeborg
Denmark.
Tel: +45 3954 5454
Fax: +45 3954 5717
Email: sten.warburg@geagroup.com
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