Seasonal variation of carrageenan yield, gel strength and viscosity in Sarcopeltis (ex Gigartina) skottsbergii from Southern Chile

Abstract

SUMMARY Chile is one of the top carrageenan producers worldwide, and Sarcopeltis (ex Gigartina) skottsbergii one of the topmost exploited carrageenophytes from the wild in the world. Total yield, gel strength and viscosity from two contrasting environments Calbuco and Ancud (Inner and Outer Sea, Chile) were estimated monthly in approximately 2 years for this species. While carrageenan yields did not show differences between localities, gametophytes in spring–summer had 15% higher, compared to tetrasporophytes. Sizes (frond surface) normally did not affect carrageenan yields. Gametophytes showed clear differences in gel strength between seasons, but not between localities, with maximum peaks during winter–spring months in Calbuco and autumn‐winter months in Ancud. Seasonal variations in viscosity were also significant. While gametophyte viscosity did not exceed 120 cPs, tetrasporophytes reached 1400 cPs in Calbuco and 1000 cPs in Ancud. More remarkably, a positive correlation between viscosity and gel strength was found in S. skottsbergii gametophytes, which is significantly different between both localities. These results suggest that selective harvesting in spring–summer should be preferred to optimize cost–benefit of harvesting activities and subsequent carrageenan productivity.

Microwave-Assisted Extraction of Carrageenan from Sarcopeltis skottsbergii

“…In that study, crude carrageenan could not be precipitated by ethanol from the extracts produced at more than 180 °C, but ultrafiltration performed well regarding carrageenan recovery yield and properties. From S. skottsbergii , other authors have reported the use of isopropyl alcohol, i.e., Matulewicz et al (1989) [ 39 ] after extraction at room temperature for 16–24 h and isopropanol precipitation obtained yields in the range 51–53%, and for Westermeier et al (2002) [ 23 ], after washing with 3% potassium chloride solution and then extraction with hot water at 90 °C for 2 h, precipitation with 97% isopropyl alcohol yielded 38–59% depending on location and season.…”

“…Variations in viscosity have been observed with location, seasonality, and life stages from gametophytes up to 120 mPa, and from tetrasporophytes up to 1000–1400 mPa [ 23 ]. The magnitude of the apparent viscosity of hybrid carrageenan found in this work is between 1000 and 2000 mPa, which is consistent with those values found suitable for the development of biofilms from other natural biopolymers such as mixtures of carrageenan and chestnut starch [ 47 ] or potato starch [ 17 ].…”

“…Microwave-assisted pressurized hot water extraction has been useful with seaweeds containing predominant structures of kappa carrageenan and hybrid mixtures of kappa/iota [ 11 , 12 , 13 , 15 ]. Other seaweeds contain a wide variety of carrageenan types; Sarcopeltis ( ex Gigartina ) skottsbergii has been reported to contain mainly κ-carrageenan, with significant amounts of ι- and ν-carrageenan [ 22 ], or a mixture α-, β-, ι-, κ-, and ξ- [ 23 , 24 ].…”

Carrageenan from Gigartina skottsbergii: A Novel Molecular Probe to Detect SARS-CoV-2

“…The seaweed Gigartina skottsbergii , class Rhodophyceae , also known as red algae, can be found in Argentina, Chile, and along the Antarctic Peninsula [ 17 ] and it is a rich natural source of carrageenan [ 18 , 19 ]. It is one of the most utilized seaweeds in Chile due to its high carrageenan content, representing over 70% of its dry weight [ 20 ]. Our research team previously investigated the biotechnological potential of subantarctic algae, such as lipidomics, and, more recently, using κ-carrageenan as a biodegradable film to activate natural oils with antimicrobial protection [ 21 , 22 ].…”

Variations on primary metabolites of the carrageenan-producing red algae Sarcopeltis skottsbergii from Chile and Sarcopeltis antarctica from Antarctic Peninsula

“…Other example is Chondrus crispus Stackhouse, which has gametophytes composed primarily of kappa-and iotacarrageenan whereas tetrasporophytes have majority of lambdacarrageenan in the cell walls (Chopin et al, 1987;Tasende et al, 2012). Besides differences on carrageenan types, Westermeier et al (2021) reported differences between gametophytes and tetrasporophytes of S. skottsbergii in relation to carrageenan yield (15% higher in gametophytes than tetrasporophytes), and viscosity (higher in tetrasporophytes than gametophytes). However, comparison on other primary metabolites, as pigments, proteins and carbohydrates among different life history phases of Gigartinaceae species still needed to be investigated.…”