Effect of potassium hydroxide on rheological and thermo-mechanical properties of semi-refined carrageenan (SRC) films. (December 2018)

• Record Type: Journal Article
• Authors: Ganesan, Abirami Ramu; Munisamy, Shanmugam; Bhat, Rajeev
• Is Part Of: Food bioscience. Volume 26(2018)
• Page Start: 104
• Page End: 112
• Publication Date: 2018-12
• Subjects: Kappaphycus alvarezii -- Rhodophyceae -- Semi-refined carrageenan -- Edible films; Food -- Biotechnology -- Periodicals; Food -- Research -- Periodicals; Aliments -- Biotecnologia -- Revistes; Aliments -- Investigació -- Revistes; Food -- Biotechnology; Food -- Research; Revistes electròniques; Periodicals; 664.005
• DOI: 10.1016/j.fbio.2018.10.003
• Languages: English
• ISSNs: 2212-4292

Abstract

Abstract: KOH is widely used for extraction of semi-refined carrageenan (SRC). The concentration levels of KOH used in extraction can significantly influence SRC qualities and edible films developed. SRC extracted from red seaweeds ' Kappaphycus alvarezii' at different concentration levels (using KOH at 6%, 12%, 18% and 24%) were used to develop an edible films with 20% glycerol as a plasticizer. Results showed that the total yield of SRC ranged from 28.1% to 37.5%. A decreased sulfate level was obtained beyond 12% KOH extraction resulting in increased 3, 6-anhydrogalactose (ranged from 26.4% to 32.5%). Functional groups were confirmed using FT-IR-spectrum, which mainly showed ester sulfate groups and with a shift in the peak values measured at higher concentrations of KOH. All the formulated films were opaque and flexible with a thickness between 30.5 and 34.1 µm (moisture: 11.4–14%). All of the films had good viscoelastic properties (power law exponents (n′) being 0.34–0.98) and showed a 'gel like' behavior. The X-ray-diffractogram peak showed 2 theta at 28.4°, 37.2°, and 50.4° and was consistent with an amorphous structure. The endothermic peaks varied between 119 and 131 °C. Higher solubility was obtained in SRC films prepared with 24% KOH. Among all the formulated films, water vapor permeability ranged between 8.5 and 12.2 × 10 −10 g Pa −1 s −1 m −1 and with high tensile strength ranging between 38.1 and 47.5 MPa. Results showed optimization of KOH extraction for SRC can produce edible films with potential food packaging applications.