Presented study compared enzymatic darkening of the tuber flesh for 11 potato cultivars before and after peeling. Colours of pulp were estimated after 0, 30, 60, 180 and 240 min using two methods: subjective (colour scale 1-9) and objective Chromametr Minolta CR-300. It was found that the intensity of enzymatic darkening depended on the cultivars and time of reaction, but not on initial colour of the flesh. Darkening of potato pulp made of whole tubers was more intensive after 60, 180 and 240 min as compared to pulp made of the tubers after peeling. Obtained results indicate significant correlation between colour intensity estimated according to subjective and objective methods (r = 0.90).
Badania przeprowadzono w Polsce Północno-Wschodniej w latach 2000 - 2002. Określono wpływ zróżnicowanych dawek azotu: 60, 90, 120 kg N·ha⁻¹, stosowanych konwencjonalnie (rzutowo) lub rzędowo na plon oraz ważniejsze cechy konsumpcyjne trzech odmian ziemniaka: ‘Bard’, ‘Rybitwa’, ‘Wawrzyn’. Najwyższy plon bulw uzyskano stosując azot w dawce 120 kg N·ha⁻¹ Technika nawożenia azotem (rzutowo, rzędowo) nie różnicowała istotnie plonu. Najplenniejszą z badanych odmian była ‘Wawrzyn’. Zawartość skrobi w bulwach ziemniaka okazała się cechą odmianową. Najwyższą zawartość skrobi stwierdzono w bulwach odmiany ‘Rybitwa’. Najbardziej podatną odmianą na ciemnienie miąższu okazała się odmiana ‘Wawrzyn’.
An experiment was carried out in 2003-2005 in Parczew on the soil of good rye complex following the randomized split-plot design in three replications. The experiment factors included pre-planting treatments (ultrasonic treated and control object) and ten potato cultivars. Full manuring and uniform mineral fertilization were applied in identical rates: 80 kg N, 35 kg P, 100 kg K and 25 t·ha s¹ farmyard manure. The samples for qualitative examinations (10 potato tubers of average size) from three field replications for each plot were taken in standard may. The estimation of flesh darkening in fresh and cooked tubers was evaluated by surveying cross-section colour parameters of potato tubers in the CIELab System. Statistic processing of the results was carried out by using variation analysis. Significance of the differences was examined according to Tukey's test. Under the influence of ultrasonic treatment an improvement in colour quality of the fresh and cooked tubers was observed. The genetic traits of tested cultivars significantly affected the colour of fresh and cooked potato tubers.