1.Plant material and processing
2. Chemical properties
2.1 Titratable acidity, total soluble solids and pH
2.2 HPLC analysis of individual sugars and organic acids
2.3 Ascorbic acid content
3. Changes in antioxidant capacity and polyphenols concentration
3.1 Sample preparation
3.2 DPPH radical-scavenging activity
3.3 Ferric ion reducing antioxidant power (FRAP)
3.4 Determination of total phenolic compounds
3.5 Total flavonoids acontent
3.6 Total monomeric anthocyanin content
3.7 Rhodanine assay for gallotannins
3.8 HPLC-DAD/MSn of polyphenol and anthocyanin composition
4. Statistical analysis