Results
Title

Photo-bleached agar extracts from Gracilariopsis heteroclada.

Authors

Endoma Jr., Leonilo F.; Nuñal, Sharon N.; Traifalgar, Rex Ferdinand M.; Nacional, Loda M.; Luhan, Maria Rovilla J.

Abstract

Agar is a strongly gelling polysaccharide extracted from gracilarioids, which is processed through conventional alkaline pre-treatment and chemical bleaching. However, the use of chemical bleaching agents has associated health risks to humans and the environment. The aim of the present study was to determine the effects of photo-bleaching in combination with NaOH pre-treatments at 5, 10 and 15% concentrations on the physico-chemical properties of agar extracted from Gracilariopsis heteroclada. The results highlighted that the gel strength of photo-bleached agar extracts PBA-15 (1822.00 g cm−2), PBA-10 (1465.60 g cm−2), and PBA-5 (1067.70 g cm−2) were significantly higher than in either a commercially sourced agar reference sample (756.20 g cm−2) or a chemically bleached agar (390.94 g cm−2). The physico-chemical properties of PBA extracts fell within the acceptable limits of food-grade agar. Photo-bleached agar extracts (PBA-5, PBA-10, PBA-15) also exhibited a higher lightness (L*) and whiteness index (WI) which makes these agars ideal for microbiological use. This study demonstrated that photo-bleaching by solar irradiation improved the physico-chemical properties of agar from G. heteroclada without the use of a chemical bleaching agent.

Subjects

AGAR; EXTRACTS; HUMAN ecology

Publication

Botanica Marina, 2020, Vol 63, Issue 6, p559

ISSN

0006-8055

Publication type

Academic Journal

DOI

10.1515/bot-2020-0028