engleski

Extraction and carrier potential of pectin from sugar beet pulp and onion peel in functional delivery systems

Agro-industrial waste is considered a valuable secondary raw material for various industrial processes and the separation of various functional constituents due to its high availability and an interesting chemical composition, while simultaneously reducing environmental burden and costs. Taking into consideration the rapid expansion of the market and its increasing demands for functional foods, agro-industrial wastes show a great potential for application as new, non-food-competing sources for carbohydrate recovery and the production of new functional delivery systems. Since the previous carbohydrate analysis enabled the characterization of sugar beet pulp and onion peel as pectin-rich secondary raw materials, the aim of this study was to establish the extraction procedure with maximum pectin yields for both raw materials and to investigate the carrier potential of extracted pectin in the formulation of rosemary (Rosmarinus officinalis L.) based edible films and hydrogel microparticles. The extraction of pectin from secondary raw materials started using 70% (v/v) ethanolic solution, in order to remove the hydrophilic compounds of low molecular weight, especially the non-structural carbohydrates. In order to obtain the maximum pectin yields, the extraction solvents (HCl, EDTA), the pH and the temperature of the reaction mixture were varied. Different concentrations of pectin (1%, 2%, 3% and 4%) from sugar beet pulp and onion peel were used in order to formulate the rosemary based hydrogel particles by ionic gelation and edible films by solvent casting method. A comparative study of the physico-chemical, bioactive and sensory properties of the produced films and the microparticles was undertaken. The highest yield of onion peel pectin (25.14%) was obtained using the chelating agent (EDTA), undergoing the extraction process at 90 °C and pH 7.0, while sugar beet pulp pectin (18.24%) was extracted using HCl at 90 °C and pH 7.0. The best results regarding the morphology of the microparticles were obtained using 2% onion peel pectin. These microparticles exhibited a high encapsulation efficiency of rosemary total polyphenols (88.34 %) and hydroxycinnamic acids (92.00 %), as well as a high efficiency of retaining the antioxidant capacity (91.46 %). Although rosemary extract markedly improved the bioactive composition of all developed functional films, the film formulated using 4% sugar beet pulp pectin exhibited the best mechanical and sensory properties.

Agroindustrial waste ; Pectin ; Edible films ; Hydrogel particles ; Polyphenols

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