Alternative protocols for the production of more sustainable agar-based extracts from Gelidium sesquipedale
Journal : Algal Research , vol. 55 , p. 10 , 2021
Publisher : Elsevier
International Standard Numbers
Printed : 2211-9264
Publication type : Academic article
ARKIV : hdl.handle.net/11250/2786852
DOI : doi.org/10.1016/j.algal.2021.1...
Food from new sources
Food processing technologies
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Agar-based extracts from Gelidium sesquipedale were obtained by applying a conventional hot water treatment and alternative ultrasound- and microwave-assisted methods, with and without the application of an alkaline pre-treatment. The alkaline pre-treatment produced refined extracts with higher purity; however, extraction yields increased from 2–5% to 7–19% by omitting this step. In particular, the ultrasound-assisted extraction allowed reducing 4-fold the extraction time, while keeping constant or even increasing the yield (up to 19% for the 1 h extraction) with respect to the conventional protocol. Interestingly, the presence of proteins and polyphenols conferred the semi-refined extracts a relatively high antioxidant capacity (19–24 μmol TE/g extract). The refined extract produced by the standard protocol formed the strongest hydrogels (>1000 g/cm2). On the other hand, the semi-refined extracts produced by the alternative protocols formed slightly stronger hydrogels (337–438 g/cm2) than the refined counterparts (224–311 g/cm2), due to their greater molecular weights of the former ones. LCA assessment showed lower global warming potential for the semi-refined extracts, especially the ultrasound-assisted extraction, hence highlighting the potential of this method to produce more sustainable agarbased extracts for food-related applications.