Colour retention, anthocyanin stability and antioxidant capacity in black carrot (Daucus carota) jams and marmalades: Effect of processing, storage conditions and in vitro gastrointestinal digestion

• Processing decreased anthocyanin content and antioxidant capacity.
• Storage at 4 °C resulted in higher retention of anthocyanins than storage at 25 °C.
• Processing led to increases in percent recovery of bioaccessible anthocyanins.

There is increasing interest in food use of black carrots because of the colour stability of the anthocyanins and the substantial quantity of bioactive compounds. The influence of jam and marmalade processing, storage conditions and in vitro gastrointestinal digestion on colour attributes, total and individual anthocyanin content, and antioxidant capacity of black carrots was examined. Anthocyanins (87.6–95.6%) and antioxidant capacity (79.2–89.5%) were significantly decreased as a result of jam and marmalade processing (p < 0.05). After 20 weeks of storage, the preserved anthocyanins and antioxidant capacity in samples stored at 4 °C (53.4–81.0% and 45.2–92.0%, respectively) were higher than samples stored at 25 °C (7.8–69.3% and 12.8–60.9%, respectively). Additionally percent recovery of bioaccessible anthocyanins and antioxidant capacity determined using the FRAP assay increased after jam and marmalade processing (0.8–10.3 and 2.6–4.3%, respectively). The current study introduced a detailed understanding of the alterations in colour properties, anthocyanin content and antioxidant capacity of black carrot jams and marmalades, which can serve as novel sources of functional foods.