Rapid autographic method for detection of enzymatic browning inhibitors based on enzyme immobilization. (15th December 2018)

• Record Type: Journal Article
• Authors: Micheloni, Oscar B.; Farroni, Abel E.; García, Paula; Furlan, Ricardo L.E.
• Is Part Of: Food chemistry. Volume 269(2018)
• Page Start: 638
• Page End: 643
• Publication Date: 2018-12-15
• Subjects: Autography -- Polyphenol oxidase -- Enzymatic browning -- Natural extracts; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2018.07.025
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Enzyme inhibitors have different affinities towards the PPOs from different sources. The assay based on natural source PPO is food specific. Combination of TLC and target directed enzyme inhibition detection. Fast and cheap alternative for exploration of complex natural extracts. Abstract: This work describes a TLC-coupled bioautographic assay suitable for the separation and detection of apple polyphenol oxidase (PPO) inhibitors from natural extracts. PPO was immobilised in agar containing l -DOPA as substrate and 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) to enhance colour development. The inhibition was detected as white spots on reddish background. Minimum amount of PPO inhibitors detected was 0.0125 µg of 4-hexylresorcinol, 0.025 µg of ascorbic acid, 0.5 µg of cysteine and 1 µg of kojic acid. The assay was compatible with normal and reverse phase TLC systems and allows detecting compounds that directly had action on the enzyme as well as agents that could convert quinones back to their reduced form. The chromatographic run evidenced the different nature of enzymatic browning inhibitory compounds from garlic and onion extracts. Using natural enzymes will provide a fast and cheap alternative for target specific exploration of natural enzymatic inhibitors.