Typpi- ja kalilannoituksen vaikutus ruokaperunan laatuun

Authors

• Anita Ellala Elintarvikekemian ja -teknologian laitos, Helsingin Yliopisto
• Lasse Vanhanen Elintarvikekemian ja -teknologian laitos, Helsingin Yliopisto
• Rakel Kurkela Elintarvikekemian ja -teknologian laitos, Helsingin Yliopisto

DOI: https://doi.org/10.23986/afsci.71785

Abstract

The influence of three nitrogen and potassium levels on the specific gravity and cooking quality of the varieties Bintje and Realta in the year 1968 was investigated. In order to find out the influence of two different kinds of soil the potatoes were grown in fine sandy soil rich in organic matter (Mikkeli) and sandy gyttja clay (Vehkalahti). The potatoes were fertilized with 50, 125 and 200 kg N/ha, every rate of nitrogen combined with 100, 200 and 400 kg K2O/ha. Mealiness and flavour were evaluated from the samples fractioned into five specific gravity classes. On the basis of sensory evalutation of the different classes the amount of potatoes of high quality was calculated from all the samples. The mealiness and flavour of the potatoes representing the specific gravity class of highest total weight were considered characteristic to the sample. The specific gravity, darkening after cooking and stability of prepeeled potatoes, were also regarded as a criteria of the quality. The mean specific gravity of both varieties was lowered by nitrogen and potassium fertilizing. Similarly, the characteristic mealiness of the sample and the amount of high quality potatoes decreased with increased fertilizing. However, even the strongest fertilizing did not cause any perceptible off-flavor, although the potatoes of the strongest NK-application were differentiated from those of the weakest NK-application by triangle tests. Nitrogen or potassium fertilizing did not affect the stability of colour of pre-peeled potatoes, when discoloration was controlled once a day during storage. The effect of the variety of soil was stronger than that of fertilizing on the quality of both potato varieties.