Use of Experimental Design Methodology To Prepare Maillard Reaction Products from Glucose and Cysteine Inhibitors of Polyphenol Oxidase from Eggplant (Solanum melongena)

• Published in: Journal of agricultural and food chemistry Vol. 54; no. 14; pp. 5120 - 5126
• Main Authors: Cheriot, Sophie C, Billaud, Catherine, Nicolas, Jacques
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 12.07.2006
• Subjects: Benzoic Acid - pharmacology; Biological and medical sciences; catechol oxidase; Catechol Oxidase - antagonists & inhibitors; Cinnamates - pharmacology; Coumaric Acids - pharmacology; cysteine; Cysteine - chemistry; eggplants; enzymatic browning; enzyme inhibition; enzyme inhibitors; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - pharmacology; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; glucose; Glucose - chemistry; Hot Temperature; Hydrogen-Ion Concentration; Maillard Reaction; Maillard reaction products; Propionates; purification; Solanum melongena; Solanum melongena - enzymology; Sorbic Acid - pharmacology; Time Factors; Heat treatment; Cysteine; Vegetables; Methodology; enzymatic browning; Catechol oxidase; Glucose; Eggplant; Dicotyledones; Angiospermae; Carbohydrate; polyphenol oxidase; Solanaceae; Solanum melongena; Enzyme; Reaction product; Use; Maillard reaction products; Maillard reaction; Browning; Experimental design; Aminoacid; Spermatophyta; Inhibitor; Oxidoreductases; Enzymatic reaction
• DOI: 10.1021/jf060228r
• ISSN: 0021-8561

Polyphenol oxidase (PPO) from eggplant was extracted and partially purified by a two-step fractionation−precipitation using ammonium sulfate and phenylsepharose hydrophobic interaction chromatography. The eggplant PPO extract was characterized concerning its kinetic properties. Optimal conditions to obtain Maillard reaction products (MRPs) with a maximal inhibitory potency (IP) toward PPO activity were determined using the surface response methodology and a four-factor and five-level experimental design. The MRPs were prepared from cysteine (0.25 M) and glucose (0−1 M), at several initial pH values (2−6) and at differing heating times (3−19 h) and temperatures (95−115 °C). The maximal IP was obtained after heating a model system of glucose/cysteine (1/0.25 M) at pH 2 for 3 h 20 min at 115 °C. The soluble part of this MRP, called MRPIPmax, was a noncompetitive inhibitor toward eggplant PPO. The IP of MRPIPmax on PPO activity was very potent as compared to that displayed by benzoic, p-coumaric, and t-cinnamic acids, as well as sorbic acid and 4-hexylresorcinol. The activity of preincubated PPO at 0 °C with MRPIPmax was only slightly restored after dialysis or gel filtration. Keywords: Maillard reaction products; cysteine; eggplant; polyphenol oxidase; enzymatic browning