2.4. Digestion procedures
2.4.1. Juice samples
Five millilitres of sample juice was transferred into a 250-
ml Erlenmeyer flask and 10ml concentrated sulfuric acid was
added. The solutionwas diluted to about 75ml by distilledwater.
Afterwards, it was cooled, filtered and washed with water and
the filtrate was collected in a 100-ml calibrated flask and diluted
to the volume with water. For the analysis, 0.5ml of the obtained