objective: polyphenol oxidase or ppo (ec 1.14.18.1) is considered the enzyme responsible for quality deterioration and browning in different fruits during postharvest period. the objective of this study was to evaluate the antibrowning (inhibition of polyphenol oxidase activity) effect of cysteine, ascorbic acid, citric acid, kojic acid and glycine at two different ph (6 and 7) in  hawthorn. me...

In the title compound, C16H10O8·H2O, the dihedral angle between the benzene rings is 71.59 (8)°. The COOH groups make dihedral angles of 10.3 (2), 30.8 (2), 11.3 (2) and 42.3 (2)° with their attached rings. In the crystal, O-H⋯O hydrogen bonds link the components forming a three-dimensional supra-molecular network.

The title compound, C(11)H(14)O(3), is a multiple-substituted derivative of benzoic acid. Intra-cyclic C-C-C angles span a range of 117.16 (19)-122.32 (19)°. Apart from intra-molecular hydrogen bonds between hydroxyl and carboxyl groups, inter-molecular hydrogen bonds are present in the crystal structure, the latter ones giving rise to centrosymmetric carb-oxy-lic acid dimers.

The title compound, C(10)H(7)FO(4), is an inter-mediate in the synthesis of the drug Fidarestat, (2S,4S)-2-aminoformyl-6-fluoro-spiro[chroman-4,4'-imidazolidine]-2',5'-dione. The di-hydro-pyran-one ring adopts an envelope conformation with the asymmetric C atom in the flap position. In the crystal, the mol-ecules are linked into zigzag chains along [100] by O-H⋯O hydrogen bonds and C-H⋯π inter-...