Structural identification of compounds for use in the detection of juice-to-juice debasing between apple and pear juices

- 4-O-p-Coumarylquinic acid was identified as a fingerprint phenolic in apple juice.
- Isorhamnetin-3-O-rutinoside was identified as a fingerprint phenolic in pear juice.
- Abscisic acid was identified as an additional fingerprint compound in pear juice.
- Chromatographic differences were found between production regions in pear juice.

The ability to detect the undeclared addition of a juice of lesser economic value to one of higher value (juice-to-juice debasing) is a particular concern between apple and pear juices due to similarities in their major carbohydrate/polyol profiles. Fingerprint compounds for the detection of this type of adulteration were identified in both commercial apple and pear juices by HPLC-PDA, were isolated chromatographically, and structurally identified by LC-MS/MS. The apple juice fingerprint was identified as 4-O-p-coumarylquinic acid and two pear compounds as isorhamnetin-3-O-rutinoside and abscisic acid. Additionally, the HPLC-PDA profile of pear juices in combination with pear fingerprint compounds including arbutin could be used to identify samples originating from China versus those from other geographical locations.