Cultured and packed sea grapes (Caulerpa lentillifera): effect of different irradiances on photosynthesis

Abstract

AbstractThe green macroalga Caulerpa lentillifera (sea grapes, green caviar) is a promising source for future nutrition due to its beneficial composition for human consumption. It is cultured in tidal ponds, mainly in Vietnam and the Philippines, and stored for shipment and retail in plastic containers, like polystyrene (PS) and polyethylene terephthalate (PET), exhibiting different properties. This study investigates the influence of irradiances on the physiology of sea grapes under culture and packaging ambience in PET using pulse-amplitude modulated (PAM) fluorometry. Fv/Fm values of C. lentillifera significantly decreased < 0.54 ± 0.06 standard deviation (SD) after 7 days of culture under 100 μmol photons m−2 s−1, but with the potential of recovery. In packaging ambience in the state of desiccation, sea grapes exposed to room irradiances (3 μmol photons m−2 s−1) for 12 days were still physiologically in a good condition (Fv/Fm = 0.70 ± 0.06). However, 12 days under irradiances of 70 μmol photons m−2 s−1 leads to decreased Fv/Fm (0.42 ± 0.11) and a moisture content of 88.2 ± 3.3% of initial. After re-immersion in sea water under room irradiances, Fv/Fm values recovered to a certain degree. In darkness, desiccation was followed by a decrease of Fv/Fm to 0.09 ± 0.19 and moisture content of 49.3 ± 20.2% of initial with no recovery after re-immersion under room irradiances. Results suggest shading of C. lentillifera in pond culture and PET containers as suitable packaging for sea grapes, but a dim light source should be provided during storage.