نمذجة عملية استخلاص البكتين من قشور الليمون باستخدام منهجية سطح الاستجابة

Abstract

Based on modern trends in environmental protection and the growing interest in the concept of recycling and the utilization of all forms of waste, this research introduces an approach for the recycling of lemon peel waste resulting from food and industrial use, transforming it into a material with added value in the food and pharmaceutical sectors.

​This study focused on determining the optimal conditions for pectin extraction from local lemon peels using citric acid as the solvent. A series of experiments were performed using various extraction conditions: pH (1.5, 2, 2.5), temperature (70, 80, 90 ˚C), and extraction times (60, 90, 120 min). These parameters were used to develop a quadratic equation based on the Response Surface Methodology (RSM) utilizing the Box-Behnken design. The validity of the model was confirmed through Analysis of Variance (ANOVA), and the significant effects of the individual factors and their interactions on extraction efficiency were investigated at a 95% confidence interval.

​The pectin extraction yield ranged from 5.3% to 28%. The lowest yield was obtained under the conditions: (pH=2.5, t=60 min, T=80 ˚C), while the highest yield was achieved under the conditions: (pH=1.5, t=90 min, T=90 ˚C). Consequently, the extraction factors (pH, T, and t) significantly influenced the pectin yield from these peels. The RSM results identified the following optimal conditions for pectin extraction: an extraction temperature of (87.79 ˚C) at a pH of (1.5) and an extraction time of (98.55 min), resulting in a maximal predicted pectin yield of 30.17%. Furthermore, the predicted values obtained using this model closely matched the experimental values within the 95% prediction limits (PL95%}) for the response (20.07-35.49%). The experimental results under the optimal conditions were found to be close to the model's predicted values and were contained within the (PL95%). Therefore, the mathematical models developed can be deemed successful and suitable for accurately predicting pectin yield within the experimental performance range.