Characteristics of polysaccharides and protein associated with them from dried and freshly collected red alga Tichocarpus crinitus

Abstract

Polysaccharides isolated by successive extraction with water at 20 and 80°C from freshly collected and dried alga T. crinitus were compared. It was shown that the yield of polysaccharides from freshly collected alga was 40-44%; from dried material, less than 25%. It was found that the amount of extracted polysaccharides and their molecular weights decreased upon storage of dried alga for three years. Polysaccharides isolated from freshly collected and dried alga had identical structures and were a mixture of N/E-and a new X-type of carrageenan. It was shown that protein, the amount of which reached 24% in the extracts obtained at 20°C, was strongly bound to the carrageenan. The amino-acid compositions of the proteins associated with the polysaccharides isolated at 20 and 80°C were identical and had an elevated content of serine, glutamic acid, glycine, and alanine.The alga Tichocarpus crinitus (Tichocarpaceae) contains carrageenan and is widely distributed in seas of the Far East. We have shown previously that the structures of gelling polysaccharides isolated from T. crinitus are N/E-carrageenans [1]. The structure of non-gelling polysaccharides is based on a repeating disaccharide unit consisting of 3-E-D-galactopyranoside-2,4-disulfate and 1,4-bound 3,6-anhydro-D-D-galactopyranoside [2].The previous studies were carried out using alga samples that were collected at one site of the Sea of Japan and stored in a dried state for a long time. Because the carrageenans isolated from the alga have sulfate groups and, therefore, can undergo autohydrolysis, the question of the influence of raw material storage times on the structure and properties of the polysaccharides isolated from it arises.Our goal was to compare polysaccharides isolated by successive extraction with water at different temperatures from both freshly collected and dried specimens of T. crinitus stored for several years.Alga T. crinitus was collected in July 2004July , 2007July , and 2008 in Rice Bay of Peter the Great Bay in the Sea of Japan during their growing season at a depth of 1.5 m. Polysaccharides were isolated by successive extraction with water at 20 and 80°C. Table 1 presents their yields. The resulting fractions were analyzed for the presence of polysaccharides by the phenol-H 2 SO 4 method determining the total monosaccharide (MS) content. The amount of polysaccharides extracted from freshly collected alga was 1.5-2 times greater than from the dried specimen. The yield of polysaccharides obtained at 20°C from both freshly collected and dried alga was less than 2%.Chemical analysis of polysaccharides isolated at 20°C from freshly collected alga showed a high content (up to 24.5%) of protein and equal amounts of galactose and glucose. The presence of the latter monosaccharide could be explained by the isolation of starch, a reserve polysaccharide of the algal cell wall. Polysaccharides isolated at 80°C contained only galactose and 3,6-anhydrogalactose, the main monosaccharides from which the disaccharide units of the carrageenans are con...

Advanced Biotechnology of Specialized Fermented Milk Products

“…A.V. Bannikova substantiating the scientific and practical aspects of the creation of technologies of products with high protein content, studied the process of encapsulation of protein and antioxidants, as well as their release under enzymatic hydrolysis in vitro [30,31].…”