Dispersion of watermelon rinds as secondary raw materials in technologies of pectin-containing extracts and film structures

The development of protective coatings based on pectin substances that serve as natural structure-forming agents developed from a secondary resource base is focused on removing a complex problem in the production of finished products by deep processing of basic raw materials and developing an original film material. At the same time, the technical result of obtaining pectin-containing film structures is their ability to protect food products from microbiological spoilage, natural losses during storage and the preservation of quality and safety indicators. An important preparatory procedure that determines the efficiency and intensity of extraction processes can be attributed to the operation of dispersing the feedstock, since it directly affects the size of the contact surface area of the phases involved in mass transfer. However, it is clear that the greater the degree of grinding, the higher the efficiency of the process, but an excessive increase can lead to additional unjustified energy costs and, as a result, to an increase in the cost of the finished products sold. In this regard, the purpose of the research is to analyze existing technologies for producing pectin-containing extracts, in which watermelon rinds can be used as secondary resources and to intensify the extraction process by conducting a rational preparatory procedure for grinding the raw materials. The object of the research are watermelon rinds as non-recyclable waste from processing watermelon raw materials. According to the obtained graphs, and taking into account the high rates of gelatinization of the obtained pectin extracts, it is possible to recommend a complex treatment of watermelon rinds, including, in addition to the operations of preliminary preparation of raw materials, ultrasonic exposure and acid hydrolysis, and it is desirable to use food acids, for example, acetic or citric, instead of aggressive sulfuric and hydrochloric acids. As a result of the study of the dispersed composition, it has been concluded that the average equivalent particle size of the dispersed raw materials does not exceed the recommended limits, that is, the result obtained can be considered acceptable.

1. Khatko Z.N., Ashinova A.A. Pectin-containing film structures: a monograph. Maykop: Publishing house of MSTU; 2019; 110 p. (In Russ).

2. Vnukova T.N., Vlashchik L.G. Functional dessert technology using natural ingredients. A Young scientist. 2015; 5-1(85):73–77. (In Russ).

3. Sathisha U.V., Jayaram Smitha, Harish Nayaka M.A., Dharmesh Shylaja M. Inhibition of galectin-3 mediated cellular interactions by pectic polysaccharides from dietary sources. Glycoconjugate Journal. 2007; 24:497–507.

4. Patent RUS № 2606831/ 2017.01.10. Gonopolsky A.M., Zinyakina E.V. Food waste shredder. (In Russ).

5. Domkin K.I., Trusov V.A., Gusev A.M. Physical foundations of particle size measurement. Proceedings of the International Symposium «Reliability and Quality». 2011; 2:376–379. (In Russ).

6. Levin A.S. Basic principles of particle size analysis [Electronic resource]. Access mode: https://www.studmed.ru/levin-as-osnovnye-principy-analiza-razmerov-chastic_c47b89a557c.html (Date of access: 05/17/2021). (In Russ).

7. Tyschenko V.M. Influence of acid-cavitation hydrolysis of plant raw materials on the yield and quality of pectin. Izvestiya vuzov. Food technology. 2011; 2–3:50–52. (In Russ).

8. Patent RUS № 2080081/ 1997.05.27. Nelina V.V., Donchenko L.V. A method of obtaining a dry pectin extract from vegetable raw materials and a method of obtaining pectin from vegetable raw materials. (In Russ).

9. Sousa António G., Nielsen Heidi L., Armagan Ibrahim The impact of rhamnogalacturonan-I side chain monosaccharides on the rheological properties of citrus pectin. Food Hydrocolloids. 2015; 47:130–139.

10. Einhorn-Stoll Ulrike Pectin-water interactions in foods – From powder to gel. Food Hydrocolloids. 2018; 78:109–119.

11. Donchenko L.V., Rodionova L.Ya., Inyukina T.A. Determination of the gel-forming ability of pectin concentrate. Izvestiya vuzov. Food technology. 2000; 2–3:31–33. (In Russ).

12. OFS.1.5.3.0004.15 Determination of authenticity, grinding and content of impurities in medicinal plant raw materials and herbal medicinal preparations [Electronic resource]. Access mode: http://pharmacopoeia.ru/ofs-1-5-3-0004-15-opredelenie-podlinnosti-izmelchennosti-i-soderzhaniya-primesej-v-lekarstvennom-rastitelnom-syre-i-lekarstvennyh-rastitelnyh-preparatah. (Date of access: 28.06.2021). (In Russ).