Cysteine's effects on chlorogenic acid quinone induced greening and browning: Mechanism and effect on antioxidant reducing capacity. (30th March 2020)

• Record Type: Journal Article
• Authors: Liang, Yundi; Were, Lilian
• Is Part Of: Food chemistry. Volume 309(2020)
• Publication Date: 2020-03-30
• Subjects: Antioxidant capacity -- Browning -- Chlorogenic acid quinones -- Cysteine -- Greening; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2019.125697
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Cysteine concentration, pH and incubation time affected color and antioxidant capacity. Cysteine inhibited chlorogenic acid (CGA)-lysine greening primarily by reduction. Cysteinyl thiols had a higher affinity for CGA quinones than lysyl ɛ-amines. Lysyl amine-CGA conjugate was the main green trihydroxy benzacridine precursor ion. The effect of CGA on CGA-amine greening and Maillard browning was decoupled. Abstract: Formation of green trihydroxy benzacridine (TBA) derivatives when chlorogenic acid (CGA) quinones and amino acids react can be unappealing for some consumers. Cysteine was studied as an anti-greening strategy, given that cysteine-CGA conjugates are colorless. Buffered 2.55 mM CGA: 5.09 mM lysine: (0–5.09) mM cysteine solutions at pH 8 and 9 were prepared and incubated for a maximum of 48 h at 22 C. Color intensity and conjugate formation was monitored spectrophotometrically, and by HPLC and LC-MS respectively, while antioxidant capacity was measured by Folin-Ciolcateau and Trolox equivalent antioxidant capacity assays. Green TBA formation was promoted at higher pH and inhibited as cysteine concentration increased. Concentration-dependent cysteine inhibition of CGA-lysine greening was attributed to redox diphenol regeneration and formation of cysteinyl-CGA conjugates, which also contributed to antioxidant capacity. pH had a greater effect on antioxidant capacity than added cysteine. Results suggested a potential anti-greening approach for alkaline CGA quinone-amine greening.