Micro Fine Grain Peeling,

 especially in Potato Processing Plants

Description of the method 

Potatoes, carrots and other tubers and root vegetables can be peeled very smoothly on DORNOW roller peeling machines and on some other DORNOW peeling lines by means of a very fine carborundum graining. We call this type of peeling micro fine-grain peeling. 

The smoothness of the surface is similar to that of steam-peeled potatoes, carrots etc. 

It is known that one can grind e. g. wood by means of fine emery paper (with a very fine graining) so smoothly that it gets a nearly mirror-like and shining surface. A similar effect is caused by the micro fine-grain tools in some of the DORNOW peeling lines with their peeling utensils which have a very fine coating. 

Advantages for the factories

The industrial potato peeling factories are enabled - by means of micro fine-graining - to market smoothly peeled potatoes of accurate appearance, even without using blade peelers. Surely, blade peeling will keep its appropriate place in many fields. Please read also our relevant paper "Blade Peeling in Industrial Peeling Plants - Necessity or Luxury?" (Q 28). 

The chips (GB: crisps) industry appears to be a good field for using machines provided with micro fine-grain coating. Although there have not yet been any relevant investigations: the smooth edges of the cut chip slices are supposed to absorb less oil than slices from coarsely peeled potatoes. 

One more advantage for the chips (crisps) industry: If micro fine-grain peeling is constantly applied, it is only the outside skins that are regularly removed. It is now common practice in the chips (crisps) industry that in the majority of cases batch peelers are used which have a coarse coating with the granulation C 14, i. e. 14 grains/cm². This type of coating is necessary in these machines, as in case of a finer graining the peeling tools tend to get choked so that the capacity of the machines falls off. 

The peeling rollers of the DORNOW roller peeling machines are self-cleaning, even when applying micro fine-grain peeling. 

Thus, you can work with a coating which removes, over the whole year, only the outer skin, even in those cases where re-coated peeling tools were put in the peeling machines.
Peeled carrots, too, offered as whole root vegetables, not cut, have a very good appearance after micro fine-grain peeling. 
Potatoes in glasses or potatoes which are sterilized in plastic bags, must have a smooth appearance. This can be achieved by micro fine-grain peeling.
 

Waste peel rates and micro fine-grain peeling 

In all those cases where it is only the outer skin of the tuber or root vegetable that has to be removed, this type of peeling will produce very low waste percentages. Wherever the product is expected to be peeled in a very accurate and clean way, one has to put up necessarily with a higher waste rate, due to the fact that deep lying damages/eyes must be taken out. This is done by means of a coarse coating. The micro fine-grain peeling can here only provide for a smooth peeling result (coarse peeling with subsequent micro fine-grain peeling can be carried out on a DORNOW roller peeling machine, with the first part of the peeling rollers being coated with coarse granulation while the last part of them has micro fine-graining). 

DORNOW peeling machines with possible micro fine grain peeling 

All peeling rollers of the DORNOW roller peeling machines of the ROW series (inner diameter ranging from 500 up to 1500 mm) can be supplied partially or entirely with micro fine-grain coating. – Machines on the web: section A, subsection 1.1

Besides, some models of the DORNOW "step-by-step" peeling lines can peel with micro fine-graining. – Machines on the web: section A, subsection 1.3 
The throughputs of the machines might possibly fall off a little when using micro fine-grain peeling. 
All machines cited above can be operated without water/waste water.

This paper contains non-committal notes. We do not lay claim to completeness. Alterations reserved. 
Our order confirmation, accepted by our customers, is in effect upon delivery. The presentation of a new edition of this treatise will substitute for any previous versions. 
Copyright by DORNOW food technology GmbH, D-40549 Düsseldorf

DORNOW total on the Web:                www.dornow.de   /    www.dornow.com

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Dornow food technology GmbH, Willstätterstr. 12, D-40549 Düsseldorf - Germany, USt-Id.-Nr. DE119264470
Tel. ++49-211-527060, Mobile ++49-172-2614932, Fax ++49-211-596883, email office@dornow.de, Internet: www.dornow.de, 
Commerzbank AG, Konto-No. 1452333, BLZ 300 400 00, Managing Director Karl-Dietrich Dornow, Amtsgericht Düsseldorf, HRB 22597