RELATIONS BETWEEN PIGMENTS, COLORING AND ANTIOXIDANT ACTIVITY OF BLACKBERRY FRUITS AND JELLIES

The objective of this study was to investigate the relationships between the amount of anthocyanins, carotenoids and the antioxidant activity measured by the FRAP and TEAC methods and the same pigments and the coloration of blackberry fruits harvested at 3 different collection points (red, intermediate and black fruits) and stored in a refrigerated environment and the jelly made from them prepared following the current legislation from 1 part of fruit to 1 part of sugar, preserved in hermetically sealed glasses, without contact with the light and temperature of 25ºC. In order to investigate the relationships between the study variables, Pearson’s correlation analysis was adopted, which indicates the existence of a positive or negative relationship between two variables, and α = 5% (correlation coefficient) was used to verify the significance of the correlation; the Mahalanobis generalized distance (D2) for the clustering analysis of blackberry fruits and jellies, by the mean linkage method between group; the cophenetic correlation coefficient and multivariate analysis using major components in order to verify the grouping of different responses of harvesting points of fresh blackberry fruit and jellies.
We observed the high degree of correlation between the content of anthocyanins and carotenoids in the fruits and between the same parameters in the jellies. The AA-FRAP method in fruits showed a negative correlation with the carotenoid content of the jellies, whereas the same method evaluated in the jellies showed a positive correlation only with the anthocyanins of the jellies. Anthocyanin is an unstable pigment, which can be degraded during processing, freezing and storage.
The results shows the positive correlation between the factors involved in the coloring of chroma fruits ‘L’, ‘a’, ‘b’ and ‘Hue’ in fruits and jellies. Chroma ‘a’ indicates the intensity of red to green (positive values are shades of red, and negative values, shades of green) but there was no evidence that anthocyanin content correlated directly with this parameter.
The results shows that components 1 and 2 (pigments and coloring components in fruits and jellies, respectively) explained 74.34% of the behavior of the variables. In relation to carotenoids and anthocyanins, these are mostly thermolabile, and one of the main causes of color loss during storage are oxidation, which is accelerated by light, temperature and the presence of metallic catalysts. In relation to the pigments evaluated and the coloring components, it is noticed that the components of the coloring show an approximation between them in both fruits and jellies. Approximation also verified among the fruits and jellies of the treatment 3 and the same of the 15th day of treatment 2 and the other fruits and jellies among themselves.
Regarding the pigments and parameters involved in the coloring, it is possible to verify by the presented results that there is greater dissimilarities between the fruits during the storage period and the respective jellies. It can be verified that at the beginning of the study (time zero), the fruits present dissimilarity. The same occurs with day 3 and at lower levels throughout the storage period. As previously explained, the degradation of the pigments throughout the storage period and the modification of the coloring parameters may explain this phenomenon.
Finally, it can be concluded that there was correlation between the content of anthocyanins and carotenoids in fruits and between the same parameters in jellies however this behavior was not clearly observed between the pigments and the antioxidant activity. There was a positive correlation between the factors involved in the coloring of chroma fruits ‘L’, ‘a’, ‘b’ and ºHue in fruits and jellies. Blackberry jellies present as good sources of anthocyanins and carotenoids.