title: Isomerization and increase in the antioxidant properties of lycopene from Momordica cochinchinensis (gac) by moderate heat treatment with UV-Vis spectra as a marker.
abstract: Momordica cochinchinensis (gac) is a plant rich in lycopene. This pigment tends to solubilize in oil and get damaged during extraction. The impact of heating on cis-isomerization of oil-free lycopene in hexane was studied at 50 and 80°C during 240min with UV-Vis spectrometry, DAD-HPLC and TEAC test. The initial all-trans-form isomerized to the 13-cis isomer more rapidly at 80°C. After this treatment, 16% of the lycopene compounds were in the 9-cis-form. This isomer triggered an increase in the antioxidant properties which was detectable from concentrations above 9% and resulted in a change from 2.4 to 3.7μmol Trolox equivalent. It is thus possible to increase the bioactivity of lycopene samples by controlling heating. The evolution of ratios calculated from the global UV-Vis spectrum was representative of cis-isomerization and spectrometry can thus be a simple way to evaluate the state of isomerization of lycopene solutions.
authors.affiliation: UMRA PAM (Food and Microbial Process), AgroSup Dijon, University of Burgundy and Natencaps, 1 Esplanade Erasme, F-21000 Dijon, France. Electronic address: phanhanh.ub@gmail.com.
authors.forename: Hanh
authors.initials: H
authors.lastname: Phan-Thi
authors.affiliation: UMRA PAM (Food and Microbial Process), AgroSup Dijon, University of Burgundy and Natencaps, 1 Esplanade Erasme, F-21000 Dijon, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Waché
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D002338:Carotenoids / Q000737:chemistry*; D006358:Hot Temperature; D007536:Isomerism; D000077276:Lycopene; D029775:Momordica / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D013053:Spectrophotometry
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D002338:Carotenoids; D000077276:Lycopene
keywords: Antioxidant; Extraction; Heat treatment; Isomerization; Lycopene; Marker; Momordica cochinchinensis (gac); Natural carotenoids