OPTIMIZATION OF PECTIN EXTRACTION FROM SUGAR BEET PULP USING MICROWAVE TREATMENT

Pectin is a natural heteropolysaccharide contained in plant cell walls and plant waste. In recent years, various alternative methods (enzymatic, microwave, ultrasonic) have been used to increase the yield of pectin, which can increase the efficiency of the process, pectin yield and improve quality. The principal advantages of using microwaves for the extraction of pectin from plant waste materials are the significant reduction in processing time, the higher yield of the natural polymer and the quality maintenance due to the more gentle processing conditions. The purpose of the work is to improve the method of pectin extraction from beet pulp using microwave treatment. Experiments were carried out to establish the optimal conditions of polysaccharide extraction. The pectin extraction was optimized by varying the microwave power, the pH of the medium, the processing time, the type of extracting agent (citric, malic, hydrochloric and acetic acids) and the ratio of beet pulp to extracting agent. A titrimetric method was used to determine the degree of esterification and the uronide component. Results and discussion. Extraction of pectin from sugar beet pulp includes the following main steps: polymer extraction by microwave treatment, pectin purification and drying. Among the studied parameters, the ratio of beet pulp to extracting agent and microwave processing time had a significant effect on the yield and properties of pectin. The highest yield of pectin (5.7%) was achieved at a heating power of 520 W, pH - 2.0, processing time of 30 minutes, using citric acid as the extraction agent and a beet pulp to extraction agent mass ratio of 15:1. IR spectra of the extracted pectin show the presence of characteristic bands typical of the pectin spectrum. Conclusions. Varying the parameters of pectin extraction from sugar beet pulp using microwave treatment allowed to increase the yield of pectin with desired characteristics. The perspective of using ecologically pure organic acids (citric and malic acids) as an extracting agent is shown.