%0 Journal Article %T Isomerization and increase in the antioxidant properties of lycopene from Momordica cochinchinensis (gac) by moderate heat treatment with UV–Vis spectra as a marker %+ Procédés Alimentaires et Microbiologiques (PAM) %A Phan-Thi, Hanh %A Waché, Yves %< avec comité de lecture %@ 0308-8146 %J Food Chemistry %I Elsevier %V 156 %P 58-63 %8 2014-08 %D 2014 %R 10.1016/j.foodchem.2014.01.040 %M 24629938 %K Antioxidant %K Extraction %K Heat treatment %K Isomerization %K Lycopene %K Marker %K Momordica cochinchinensis (gac) %K Natural carotenoids %Z Life Sciences [q-bio]/Biochemistry, Molecular BiologyJournal articles %X 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. %G English %L hal-02401943 %U https://institut-agro-dijon.hal.science/hal-02401943 %~ UNIV-BOURGOGNE %~ PAM %~ AGREENIUM %~ AGROSUP-DIJON %~ INSTITUT-AGRO-DIJON %~ INSTITUT-AGRO-DIJON-PAM %~ INSTITUT-AGRO-PAM