Sea grape (Caulerpa lentillifera) aquaculture in Van Phong Bay, Viet Nam: Evaluation of the post-harvest quality

Abstract

Caulerpa lentillifera, known as `sea grapes´ or `green caviar´, is increasingly in demand as a sea vegetable for human consumption. The seaweed is cultivated in ponds in the Khánh Hòa province in Van Phong Bay, Viet Nam, during the dry season (March-October). The harvested sea grape fronds are graded into different qualities based on their physical characteristics for retail on the local market or for export. Based on systematic observations of sea grape fronds of two different qualities, the frond weight, frond length and rachis coloration were identified as physical characteristics important for grading. Fronds of the best quality had significantly longer (12.59 ± 2.89 vs 10.01 ± 2.51 cm) and heavier (2.37 ± 0.59 vs 1.60 ± 0.5 g) fronds with darker rachis than the other quality group. However, a logistic regression model revealed that frond weight was the best predictor of frond quality. The physiological parameter of Fv/Fm was slightly different between the qualities, but always with means > 0.7, whereas the antioxidant activity and the total phenolic content were similar (98.34 ± 19.22 vs 95.96 ± 24.98 mmol TE (100 g)−1 DW and 163.8 ± 20.14 vs 149.85 ± 15.44 mg GAE (100 g)−1 DW). To the best of our knowledge, this study took a first approach to identify quality characteristics of sea grape fronds from Van Phong Bay, Viet Nam, which can serve as a basis for adjusting cultivation parameters to improve the harvest quality by developing cultivation and post-harvest protocols. However, further research is needed to investigate the effect of certain cultivation parameters on the specific frond characteristics.