Introduction: The use of natural polymers as pharmaceutical adjuvants has been consolidated with several examples. Mucilage and gums are interesting biological macromolecules for various pharmaceutical preparations because of their physico-chemical properties, such as their high swelling capacity in water; low cost; low toxicity; biocompatibility; biodegradable and due to being renewable source [1]. The water-soluble mucilage extracted from Linus usitatissimum L. is an excellent hydrocolloid potential in gel formation and, because it has high viscosity in aqueous solution, it can become a product of high technological value in the food, pharmaceutical and cosmetic industry [2]. Since the flaxseed mucilage is a natural product, the quality and properties of mucilage can vary according to the extraction process such temperature, time of extraction and pH. Objective: The objective of this work was to verify the effect of the pH of extractor liquid on the yield and soluble fiber content. Additionally, the effect of precipitation on ethanol was verified by comparative evaluation using Fourier transform infrared spectroscopy (FTIR). Methods: For that, extractions occurred at 3 different pHs (3,8, 6,45 and 9,6) for a period of 13.25 hours at 45 oC. The flask were kept in a shaker with temperature controlled under stirring at a speed of 180 rpm. After the time set for extraction, the samples were filtered and the supernatant was frozen and lyophilized. The method used to perform the total fiber quantification was the official non-enzymatic method recommended by AOAC 993.21 [3] for samples with low starch content (less than or equal to 2%). The transmittance spectra of the mucilage samples were obtained in the infrared (IR) spectrophotometer (Nicolet- Model: IS50 FT-IR). It was used the product extract from linseed before and after the purification of ethanol. Results and discussion: The highest yield was obtained at pH 6,75 and the highest soluble fiber content was obtained at pH 9,69. Extraction in an aqueous medium with acid pH also resulted in a good amount of biological macromolecules. Cui et al. [4] indicated the highest extraction at pH 2. Studies of mucilage extraction at basic pH were not observed in the searched databases. By characterization using IV-FTIR, it was verified that the extraction of the macromolecules of the flaxseed in the basic medium (pH 9,6) presented the highest quantity and the best characteristics in relation to the degree of purity. Conclusions: In the present study it was possible to determine that the experimental pH, among those used in the work, to obtain the largest amount of fiber extracted from the seed of Linum usitatissimum L., was 9.6. The purification step with ethanol is not important to extraction at basic pH, while at pH 6,45, this step is critical.
References:
[1] PRAJAPATI, V. D. et al. Carb Polymers, v. 92, n. 2, p. 1685-1699, 2013.
[2] CHEN, H.H. et al. Jf food engineering, v. 77, n. 2, p. 295-303, 2006.
[3] AOAC (Association of Official Analytical Chemists). Official Methods of Analysis, 17th ed. Association of Official Analytical Chemists, Gaithersburg, MD. 2000.
[4] CUI, W. et al.. LWT-Food Science and Technology, v. 27, n. 4, p. 363-369, 1994.
Aknowledegements: PPG-CAPS, PROPPI-UFF, LURAEx-UFF