Effects of freezing and thawing on some agar parameters of <i>Eucheuma spinosum</i> and <i>Gracilaria confervoides</i>

Abstract

Agar was extracted from two agar-containing red algae species, namely Gracilaria confervoides and Eucheuma spinosum. Qualitative assessment was made on the agar extracts, which included percentage yield, gel strength, syneresis, and hysteresis range. The quality of agar extracts derived from this study was compared to commercial agar-agar. The. effects of each parameters, repeated freezing and thawing on agar were also investigated. Qualitative test showed that percentage yield from Gracilaria was higher than Eucheuma. Gel strength and hysteresis range of agar from commercial sources and Gracilaria were higher compared to Eucheuma. On the other hand, syneresis range was highest in Eucheuma agar. Repeated freezing and thawing lowered percentage yield and syneresis but increased gel strength and hysteresis of agar extracts from agar sources used.