ANTHOCYANINS, SOLUBLE SOLIDS, AND TITRATABLE ACIDITY IN BLACKBERRIES AS INFLUENCED BY PREHARVEST TEMPERATURES

Anthocyanins, titratable acidity, and soluble solids in blackberry fruits were determined daily for one week during ripening, beginning at a prescribed color maturity of the single fruits.
The cultivars ‘Black Thornfree’, ‘Smoothstem’ ‘Thornless Evergreen’, and ‘Theodor Reimers’ (syn. ‘Himalaya’) were used.

Refractometer readings increased continously during ripening, being positively correlated to temperatures.
During warm weather conditions anthocyanin concentrations in fruit juice reached their highest levels between the third and the fifth day of the ripening period, but then a decrease followed which was more rapid than observed at low temperatures.
The loss of acids was accelerated with increasing preharvest temperatures.
There were slight differences due to cultivars.

For preparation of fruit juices high concentrations of anthocyanins and acids are desirable, whereas for the fresh-market low acidity and high sugar contents are preferred.
Considering preharvest temperatures it should be possible to influence fruit quality by modifying the intervals between pickings in order to adjust some fruit constituents to the demands of the market or of the juice industry.

Symposium on Breeding and Machine Harvesting of Rubus

W.D. Naumann, U. Wittenburg

https://doi.org/10.17660/ActaHortic.1980.112.25