Differences in fruit colour development, anthocyanin content, fruit quality and consumer acceptability of eight ‘Gala’ apple strains

The effect of strain on fruit colour development, chromaticity values and anthocyanin content, fruit quality and consumer acceptance was evaluated on eight ‘Gala’ apple strains (Malus domestica Borkh.) at the IRTA (Spain), during a period from 4 weeks before to 1 week after commercial harvest. Based on fruit colour, measured with a Minolta CR-200 portable tristimulus colorimeter, and anthocyanin content, the most coloured strains were ‘Royal Beaut’, ‘Buckeye Gala’ (both semistriped) and ‘Ruby Gala’ (blushed). ‘Brookfield’ and ‘Schniga’ (both striped) provided an intermediate level of colour, while ‘Galaxy’ and ‘Mondial Gala’ (both striped) were the least coloured ones. The most important increase in colour development was recorded from 2 weeks before the commercial harvest and continued also increasing after harvest. Highly coloured strains developed a red colour on both fruit sides with greater average of fruit surface coloured, while the less coloured strains exhibited different colouration between sides, more bicolour fruits and lower average of fruit coloured.Fruit size and yield were, in general, the same for all strains. Instrumental fruit quality parameters along the different harvest date: fruit firmness, soluble solids content (SSC), titratable acidity (TA), and starch index were similar for the different cultivars. Differences in fruit colour/anthocyanin content were not related to differences in fruit quality parameters of different strains. Thus, ripening time was not related to the degree of fruit colour.Principal component analysis of the samples characterized by all the variables showed a chronological distribution along the first principal component PC1, indicating different maturity stages. Internal preference mapping showed three consumer clusters and indicated that the largest number of consumers preferred samples harvested at commercial harvest or 2 weeks before this date. We also observed a clear influence of maturity stage on consumer acceptance but there was no clear influence with respect to strain.