Optimization of extraction process parameters of caffeic acid from microalgae by supercritical carbon dioxide green technology

PURPOSE: In this study, the optimization of extraction process parameters of caffeic acid content from Spirulina platensis is performed by supercritical green technology. METHODS: Especially, the optimization of supercritical carbon dioxide (SC-CO(2)) extraction parameters was carried out employing Box-Behnken design (BBD) and response surface methodology (RSM). Alongside, the three levels of extraction parameters i.e. extraction pressure, extraction time and temperature have been fixed. As a response, the caffeic acid content of the extracts was determined by HPLC. The statistical analysis (ANOVA) of developed mathematical models was used in the process. RESULTS: The extract exhibited the highest content of caffeic acid as 72.11 µg/g of dw at the optimized extraction conditions of 360.08 bar pressure for 57.13 min extraction time at 38.31 °C temperature. Simultaneously this extract exhibited the highest content of total phenolic content (76.87 µg GAE/g dw), reducing power (2278 µg BHT/g dw), FRAP value (4.19 mM FeSO(4) equivalent/g dw) and IC(50) for DPPH activity (89.28 µg/mL). CONCLUSION: It has been also noted that supercritical fluid extract can significantly retard the growth of microorganisms in litchi beverage. Consequently, we can also predict that isolated SC-CO(2) antioxidant containing fraction would have hopeful for foodstuff preservative.