Ultrasound Extraction Mediated Recovery of Nutrients and Antioxidant Bioactive Compounds from Phaeodactylum tricornutum Microalgae

Fadila Al Khawli,Francisco J Barba,Emilia Ferrer,Francisco J Martí-Quijal,Noelia Pallarés

doi:10.3390/app11041701

Fadila Al Khawli, Francisco J Barba + Show 3 more

Open Access

https://doi.org/10.3390/app11041701

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Journal: Applied Sciences	Publication Date: Feb 14, 2021
Citations: 29	License type: CC BY 4.0

Affiliation: University of Valencia

Abstract

In recent years, a growing interest has been shown in the use of microalgae due to their interesting nutritional and bioactive profiles. Green innovative processing technologies such as ultrasound-assisted extraction (UAE) avoid the use of toxic solvents and high temperatures, being a sustainable alternative in comparison with traditional extraction methods. The present study aims to evaluate the recovery of high added-value compounds from Phaedoactylum tricornutum assisted by ultrasound. To optimize the UAE of proteins, carbohydrates, pigments and antioxidant compounds, a response surface methodology was used. Carbohydrate extraction was positively affected by the temperature. However, for the extraction of carotenoids, the most influential factor was the extraction time. The total polyphenols were only significantly affected by the extraction time. Finally, the antioxidant capacity, measured by 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), was strongly modulated by the extraction time, while for the oxygen radical antioxidant capacity (ORAC) assay, the most important parameter was the temperature, followed by the extraction time. The optimal conditions for the maximum extraction of nutrients, bioactive compounds and antioxidant capacity were 30 min, 50 ºC and a pH of 8.5. Finally, it has been seen that with these conditions, the extraction of fucoxanthin is allowed, although no differences were found between an ultrasound-assisted extraction and a shaking extraction (control).

Highlights

Over the last two decades, there has been growing interest in the use of microalgae as food to partially replace conventional food products or to be used as a source of high added-value compounds [1]
The optimization was carried out to obtain the maximum values of all the studied responses: proteins, carbohydrates, chlorophyll A, total carotenoids, total phenolic compounds, TEAC
After 16 min, this value decreased (Figure 5). This is in close agreement with the results reported by Parniakov et al [17] for Nannochloropsis spp., who found that the optimal extraction of the total phenolic compounds assisted by ultrasound (W= 400 W) was achieved after 15 min

Summary

Introduction

Over the last two decades, there has been growing interest in the use of microalgae as food to partially replace conventional food products (e.g., meat) or to be used as a source of high added-value compounds [1]. Marine microalgae consist of prokaryotic or eukaryotic photosynthetic microorganisms that are able to grow rapidly due to their unicellular or simple multicellular structures [2]. The main reason for the increased microalgae exploitation is due to their interesting nutritional and bioactive profiles (e.g., high protein content, healthy lipid profile and micronutrient (vitamins and minerals) composition) [3]. The nutritional and bioactive profiles of microalgae differ according to the target species. There is a need to explore and evaluate each microalgae species separately

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