Quality of potatoes in relation to soil and season II. The colour of the cooked potato

Abstract

Samples of potatoes were collected in three successive seasons from a wide range of soil types and their liability to stem-end blackening determined.Variety and season of growth affected the amount of stem-end blackening which developed.All soil types gave samples with a wide range of stem-end blackening, but the average amounts of blackening in samples from different soil types were shown to differ significantly. Samples from fen, blackland, sand, gravel, limestone and chalk blackened more than those from skirt, silt, warp, clay and boulder clay.The pH of the expressed sap of tubers was independent of the type of soil in which they were grown, but dependent on variety and locality of growth. No evidence that the pH of the tubers influenced the amount of stem-end blackening pigment was obtained.The yellowness of the flesh of tubers showed an approximately normal distribution. Slight evidence for an effect of soil type on the amount of yellow pigment was obtained.The work described above was carried out as part of the programme of the Food Investigation Board of the Department of Scientific and Industrial Research.