Optimizing of the organic potato production for french fries and chips
For years consumers in Germany have been consuming more and more processed potato products, such as chips or potato crisps, than fresh potatoes. But the predominant proportion of organically produced potatoes is marketed as table potatoes, so that the proportion of processed organic potato products has up to now been low. Reasons for this are the high, specific required quality demands for potato processing and a low consumer demand for table potatoes.
In Germany, the acreage of organically cultivated potatoes has been about 8,000 ha for many years. So far, only a small proportion of organic potatoes is processed into chips or potato crisps. Specific varieties have to be cultivated if chips and potato crisps are to be processed. These differ significantly from the required quality criteria for those potatoes for human consumption. This is applicable to both, external (e.g., grading size) and internal quality criteria (starch content, reducing sugar content, etc.), as well as for the suitability for storage. Only through targeted, purposeful and production adapted to the specific conditions of Organic Farming can the high demands of the processing sector be fulfilled.
The aim of the project was to work out strategies for the production of high-quality processing potatoes under the conditions of Organic Farming. Therefore the focus was set on the effects of agronomic measures (choice of varieties, preceding crops, irrigation, and organic fertilisation).
For a successful potato cultivation for processing not only a high yield is necessary, but also the high product-specific quality standards for chips and potato crisps set by the processing industry must be fulfilled. Chips, for example, require a high proportion of large-grading tubers, for potato crisps rigorous criteria consist for the content of reducing sugars. To avoid high sugar contents, the potatoes are stored at 8°C, which increases the demands on the suitability for storage. The choice of variety is of crucial importance. So, the varieties Agria and Marena can be recommended for chip production, they showed high tuber yields of the required size grade (> 50 mm) and a good quality at harvest and after storage. For processing to potato crisps the variety Marlen is suitable, which was relatively stable in storage. Depending on the degree of maturation process the tolerable concentrations for reducing sugars after storage can be quickly exceeded. Therefore, the 4°C varieties Sempra and Verdi are an alternative, but their yield was not satisfying.
Furthermore results confirm that all agronomic possibilities regarding a good nutrient and water supply as well as the seed-tuber treatment should be exploited in order to achieve high yields with the required tuber sizes and an addressing quality of raw materials. In particular, legumes crops (field peas with a following catch crop or clover-grass leys) are well suited as a previous crop. The clover-grass management (cutting or mulching) has no significant effect on yield, grading and product quality. On light, sandy soils a quality-promoting fertilization of potassium – via stable manure or mineral fertilizer accepted in Organic Farming is a high recommendable tool.
On light soils a uniform water supply must be ensured by irrigation, it also contributes to an improved N-use of organic fertilizer. N-containing organic fertilizer (horn meal) showed better results compared to stable manure. While agronomic measures had an effect on the processing quality, a much more strong effect was given by the weather conditions and the so dependent growth pattern.
Conclusion: processing potatoes can be successfully cultivated when site- and farm-specific circumstances are involved.
5.2003 - 10.2005
Project funding number: BÖL 03OE003
Funding program: Bundesprogramm Ökologischer Landbau und andere Formen nachhaltiger Landwirtschaft (BÖLN)
Project status: finished