CIELAB analysis and quantitative correlation of total anthocyanin content in European and Asian plums

摘要

Fruits are a rich source of vitamins and antioxidants and their consumption is important for human health. Anthocyanins contribute to antioxidant characteristics in colourful fruits, especially with blue, purple and red tones of colour. The aim of this work was to study the correlation between anthocyanin content and the external colour of plums. European (Prunus domestica) and Asian (Prunus salicina) plum cultivars and inter -specific hybrids of the Japanese plum and the apricot (Prunus armeniaca) - pluots were chosen for this investigation. Results showed that total anthocyanin content in fruits ranged between 0.2 and 217.0 mg kg' fresh weight (FW) among varieties. High anthocyanin values were measured in cultivars derived from the Japanese plums 'Black Amber' and 'Black Star', however, the highest values were surprisingly measured in the pluot 'Flavorich Anthocyanin values for European plum cultivar 'Cat'anska rodna' corresponded to the previous scientific studies and reached the level of 77.0 mg kg-1 FW. The colour of the fruit was measured using the colour scale set by the Commission Internationale de L'Eclairage (CIELAB) and from chromatic parameters L*, a*, b* the chroma parameter (C*,), hue angle (h,) and colour index of red grapes (CIRG) were calculated. Correlation of the colour parameters with the anthocyanin content in plum fruits was determined and it was found that CIRG is a suitable comparison parameter with exponential positive correlation to anthocyanin content. The present work highlights that colour parameters, especially CIRG, are a good identifier of approximate value of anthocyanin content with using founded regression function. This method could be used to obtain an overview about healthy substances of fruit without its destruction or using chemical analyses.