Extraction, yield and properties of Kappaphycus alvarezii (Doty) Doty ex P. Silva carrageenan, in experimental cultivation in Ubatuba, São Paulo

Author(s)

Leila Hayashi

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2001-12-10

Examining board members

Edison Jose de Paula; Eurico Cabral de Oliveira Filho; Renata Perpetuo Reis

• Advisor: Edison Jose de Paula

Abstract

ABSTRACT Cap.2 Procedures for the quantification of carrageenans generally involve drying of seaweed, followed by washing, alkali treatment, extraction in water or in lightly alkaline solutions, and separation of the carrageenan from the residues. Obtained results depend mostly on the various methods involved and equipment utilized. This paper was designated with the purpose of standardizing the extraction process of the Kappaphycus alvarezii (Doty) Doty, farmed in Ubatuba, SP, so as to maximize the final yield of the extracted carrageenan. Best results were obtained with algae under cold alkali treatment (potassium hydroxide), followed by hot treatment in 6% concentration at a temperature of 80oC for two hours, which made the later filtering easier. A proportion of 5g of the seaweed, treated in cold alkaline solution in 400mL of water, was established for the extration. A nylon filter was selected as the most efficient for the carrageenan\'s separation. ABSTRACT Cap. 3 Carrageenans are commercially important hydrocolloids, because of their characteristics as gelling and stabilizing agents. Their yield is regarded with great interest, but nevertheless, published studies show wide variations. The purpose of this paper is to analyze and compare carrageenan yields and their possible seasonal variations in Kappaphycus alvarezii (Doty) Doty farmed in Ubatuba, SP, between 1999 and 2000. Brown, green and red tetrasporophytes were studied, as was also, a strain derived from tetraspores. Results were compared with Hypnea musciformis (Wulfen)Lamouroux from Ubatuba and with commercial samples of Kappaphycus spp. Highest yields were obtained from the strain derived from tetraspores and from the commercial samples, which produced very similar values. Brown, green and red tetrasporophytes produced lower yields, with similar values among itselves. Seasonality was observed among the yields of the 4 strains of K. alvarezii, which showed negative correlation with the growth rates. Carrageenans of H. musciformis showed lowest yields as compared with other analyzed samples. ABSTRACT Cap. 4 Gel strength and chemical characteristics (sulphate and 3,6 anhydro-Dgalactose contents) are outstanding parameters for the evaluation of the carrageenan quality. The purpose of this paper is to analyze and compare gel strength and 6-sulphate and 3,6 anhydro-D-galactose contents of the carrageenan extracted from Kappaphycus alvarezii (Doty) Doty farmed in Ubatuba, SP, in 2000. Those parameters were evaluated for carrageenan samples submitted to different treatment carried out previously to the extraction (no alkali treatment, cold alkali treatment, hot alkali treatment and cold alkali treatment followed by hot). The carrageenan extracted from seaweed submitted to cold alkali treatment followed by hot produced the best quality gels, with the highest 3,6 anhydro-D-galactose content and gel strength. Carrageenans of brown, green and red tetrasporophytes as well as of a strain derived from tetraspores, were also analysed. Best results were obtained from the strain derived from tetraspores as compared with the others. Samples of Hypnea musciformes (Wulfen)Lamouroux were also utilized for the gel strength analysis, as well as commercial samples of semi-refined carrageenan, which presented lower values as compared to those of the K. alvarezii. Similar values of gel strength were observed in the commercial samples of Kappaphycus spp. and in the strain derived from tetraspores. (AU)