Physico-chemical properties of agar extracted from Gracilariopsis longissima (formerly Gracilaria verrucosa) and development of plant-based food jellies

Abstract

In this study, agar was extracted from red seaweed, Gracilariopsis longissima (formerly G. verrucosa) by hot water extraction, and the physicochemical and gelling properties of the extracted agar were examined. Furthermore, attempts were made to develop plant-based food jellies and compare them with gelatine-added jellies. The moisture, total lipid, total carbohydrate, total ash, and crude fiber content of the dried Gracilariopsis longissima (formerly G. verrucosa) were 6.55±0.01%, 1.63±0.04%, 6.09±0.29%, 4.88±0.26%, and 12.41±0.57%, respectively. Extraction of agar was conducted under three different temperatures such as 50 °C, 70 °C, and 90 °C and the highest dried agar powder yield was gained at 90 °C. Further, the highest melting temperature, gelling temperature, and pH were displayed by agar gel prepared using agar powder extracted at 90 °C and values were 60.33±1.53 °C, 37.00±1.00 °C, and 6.23±0.03, respectively. Moreover, plant-based food jellies were developed with 4, 8, and 12 g of agar extracted from Gracilariopsis longissima (formerly G. verrucosa) instead of gelatine. According to the sensory evaluation results, the highest preference was achieved by 12 g agar-added jellies. In conclusion, agar from Gracilariopsis longissima (formerly G. verrucosa) is an alternative plant-based gelling agent that can be used in the manufacture of food jellies.