Optimization of an ecofriendly pectin extraction from rosa rubiginosa L. husk by response surface method

RIVEROS-GOMEZ M.; RODRIGO TORRES-SCIANCALEPORE; PODETTI C.; ZALAZAR GARCÍA D.; DANIELA ASENSIO; MARÍA PAULA FABANI; FOUGA G. G.; GERMÁN MAZZA; ROSA RODRIGUEZ

Buenos Aires

Congreso; 11 th World Chemical Engineering Congress; 2023

Asociación Argentina de Ingenieros químicos

Rosa rubiginosa is a wild shrub from Rosaceae family that presents invasive characteristics in the South of Argentina as a consequence of its ease of territorial expansion [1]. The fruit is widely harvested due to the pharmaceutical, cosmetic, and gastronomic benefits. Rosehip husk (RH) is the dehydrated mature receptacle, shredded, and without seeds, from which different high added value compounds such as pectins may be extracted. These are complex polysaccharides with many industrial applications for its gelling, thickening and adsorption properties. The traditional pectin extraction method consists in the immersion of the biomass to perform the hydrolysis in an inorganic acid solution, assisted by stirring and temperature.In this work, an alternative and ecofriendly method for RH pectin extraction is proposed using citric acid assisted by ultrasound and temperature, being this acid less pollutant and less expensive compared with hydrochloric, sulfuric, and nitric acids. The ultrasonic bath is an efficient technology that uses acoustic energy to enhance pectin diffusion and reduce the extraction time [2]. Box-Behnken design was used to model the pectin extraction process and to determine the independent variables values to be used in the experiments: pH of citric acid solution (pH, 2 – 3), temperature (T, 70 – 90 °C), and time (t, 30 – 60 min). For each experiment, RH was placed in Falcon tubes and the citric acid solution was added (1/25 ratio) and immersed during the corresponding time in the ultrasonic bath previously heated. After that, pectin was precipitated by adding ethanol (96 %), filtered, and purified to calculate the yield of extraction (η). Additionally, an estimation of extraction cost was made considering the energy consumed and materials used in the process. A second-order polynomial function was adjusted for η and cost calculated with the experimental results, and response surface plots were obtained. Applying a genetic algorithm, a multiobjective optimization was used to find acceptable solutions that maximize η, and minimize cost for decision-making. The optimal extraction conditions for obtaining the most acceptable compromise between variables were: T = 79.81 ºC, t = 55.04 min, and pH = 2.09, being the optimal η and cost 29.48 % and 6.00 USD/kg of pectin, respectively.Finally, pectin was characterized at the optimal condition to determine some quality parameters: aw (water activity) = 0.55±0.01, ash content = 3.13±0.04 %, equivalent weight = 281.00±9.31 g/mL, methoxyl content = 4.42±0.22 %, and degree of esterification = 28.59±0.78 %. The results showed that RH is an excellent source of low-methoxyl pectin at low cost and could be used in food preparations.