Effects of Improved Post harvest handling on the chemical constituents and quality of carrageenan in reg algae, Kappaphycus alvarezii Doty

Charles Santhanaraju Vairappan, and Rossnita Razalie, and Ummul Mardiah, and Tulasiramanan Ramachandram, (2013) Effects of Improved Post harvest handling on the chemical constituents and quality of carrageenan in reg algae, Kappaphycus alvarezii Doty. Journal of Applied Phycology, 26 . pp. 906-916. ISSN 0921-8971

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Official URL: Http://dx.doi.org/10.1007/s10811-013-0117-1

Abstract

Red alga Kappaphycus alvarezii Doty is an impor-tant commercial species widely cultivated in southeast Asian countries for its polysaccharide, kappa-carrageenan. Com-mon post-harvest handling technique involves sun-drying of harvested seaweed on platforms at the farms. Quantity and quality of carrageenan varies depending on the duration and care taken during the post-harvest handling of the raw sea-weed. In this study, dynamics of moisture content, water activity index (aw), carrageenan yield, and carrageenan qual-ity were investigated by subjecting the seaweed to three post-harvest methods: (1) freeze-drying (FD), (2) shade-drying (SD), and (3) direct sun-drying (DSD). Seaweed dried under FD and SD produced high yield (56–58 %), superior gel strength (1,454–1,424 g cm −2), high viscosity (57–58 cPs), and low syneresis (15–17 %). But, carrageenan extracted from DSD seaweed gave 28 % lower yield, 38 % lower gel strength, 27 % lower viscosity, and 8–9 % higher syneresis. In addition, gelling temperature and melting temperature of the DSD carrageenan were lower by 4 and 9 °C, respectively. Molecu-lar size analyses of carrageenan extracted from seaweed dried under FD and SD contained carrageenan of 700 KDa (80 %) and 200 KDa (4–10 %). However, carrageenan extracted from DSD seaweed contained smaller carrageenan molecules, 460 KDa (55 %), 210 KDa (25 %), and <100 KDa (20 %). Further, scanning electron microscope images illustrated the severe effects of DSD on the morphology of seaweed cells. Therefore, SD technique was found to be the best post-harvest processing technique that gave quality carrageenan in a high quantity. Due to its simplicity and low cost, it is a practical approach to be practiced in southeast Asian countries.

Item Type:Article
Uncontrolled Keywords:Post-harvestprocessing, Desiccation, Chemical constituent, Carrageenophyte
Subjects:Q Science > QD Chemistry
Divisions:FACULTY > Faculty of Business, Economics and Accounting
ID Code:12017
Deposited By:IR Admin
Deposited On:20 Oct 2015 13:39
Last Modified:20 Oct 2015 13:39

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