Kahdella eri lannoitustasolla viljeltyjen perunalajikkeiden laatu ruokaperunana

Abstract

Abstract. The cooking quality of 14 different potato varieties was investigated. The varieties were Dore, Ersteling, Ostara, Siikkli, Sirtema, Tanja (early potatoes) and Alfa, Bintje, Milva, Patrones, Realta, Rekord and Tombola (late potatoes). Every variety was cultivated in two different levels of fertilization; the so-called normal fertilization was 75 kg N/ha, 200 kg K 2 O/ha, 190 kg P 2O s /ha, while the richer one was double compared to the former. Mealiness and flavour were evaluated from the samples fractioned into five specific gravity classes. On the basis of sensory evaluation 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 the keeping quality of prepeeled potatoes, were also regarded as criteria of the quality. Increased fertilization decreased the mean specific gravity of every variety. The amount of high qualitypotatoes varied o -2 B 0 -28 tn/ha depending on the variety and the application of fertilization.Increased fertilization increased the amount of high quality potatoes of early varieties but decreased the amount of high quality potatoes of later varieties. Sloughing was a problem only with Milva, which makes difficult its use in a normal way. Prepeeled potatoes stayed unblackened I-s days depending on the variety. The keeping quality was not affected by fertilization. The effect of increased fertilization on the flavour was studied by comparing the potatoes of the same specific gravity grown on normal fertilization with those grown on a richer one by triangle tests. Fertilizing affected noticable difference in the flavour of the varieties Siikli, Tanja, Realta and Patrones but not in the other varieties.Teollisuusruokaperunan tuotantomahdollisuuksia Kaakkois-Suomessa tutkittiin Itä-Suomen Raakasokeritehdas Oy:n toimesta kesällä 1968. Viljelykokeilla selvitettiin mm. eri typpi-ja kalilannoiteyhdistelmien vaikutusta Realtan ja Bintjen satoisuuteen ja sadon laatuun (Ellala ym. 1971). Samassa yhteydessä koeviljeltiin kahdella eri lannoitustasolla 14 eri perunalajiketta. Ruokaperunakelpoisuuden osalta tutkimukset tehtiin yliopiston elintarvikekemian ja -teknologian laitoksella. Materiaali ja menetelmätLajikkeet.