University of Tehran Press Iranian Journal of Biosystem Engineering 2008-4803 51 4 2021 02 19 Optimization of Pectin Xxtraction from Unriped Grape Pomace Using Citric Acid and Investigation of Its Physicochemical Properties Optimization of Pectin Xxtraction from Unriped Grape Pomace Using Citric Acid and Investigation of Its Physicochemical Properties 793 804 80011 10.22059/ijbse.2021.297320.665272 FA Mehdi Rezaei Department of Food Science and Engineering, Faculty of Agricultural Engineering & Technology, University of Tehran, Karaj, Iran Faramarz Khodaiyan Department of Food Science and Engineering, Faculty of Agricultural Engineering & Technology, University of Tehran, Karaj, Iran Zeinab Mousavi Department of Food Science and Engineering, Faculty of Agricultural Engineering & Technology, University of Tehran, Karaj, Iran Seyed Saeid Hosseini Department of Food Science and Engineering, Faculty of Agricultural Engineering & Technology, University of Tehran, Karaj, Iran Milad Kazemi Department of Food Science and Engineering, Faculty of Agricultural Engineering & Technology, University of Tehran, Karaj, Iran Journal Article 2020 02 13 In this study, unrippen grape pomace as a valuable source for pectin extraction was investigated using acidic extraction method. For this purpose, Box-Behnken design with four independent variables in three levels (Time (30-90 min), Temperature (70-90℃), pH (1.5-3.0) and liquid to solid ratio (20-40 v/w)) was used to optimize the pectin extraction yield that the highest pectin extraction yield in the optimum conditions (time of  85 min, the temperature of 90℃, pH of 1.5 and liquid to solid ratio of 20 (v/w)) was 26.1 ± 1.0%. The results showed that unrippen grape pomace pectin had degree of esterification of 51.6%, galacturonic acid content of 66.1%, emulsifying activity of 57.2%, and also showed favorable emulsion stability. The FT-IR spectrum confirmed the presence of esterified poly galacturonic acid structure in pectin sample. In this study, unrippen grape pomace as a valuable source for pectin extraction was investigated using acidic extraction method. For this purpose, Box-Behnken design with four independent variables in three levels (Time (30-90 min), Temperature (70-90℃), pH (1.5-3.0) and liquid to solid ratio (20-40 v/w)) was used to optimize the pectin extraction yield that the highest pectin extraction yield in the optimum conditions (time of  85 min, the temperature of 90℃, pH of 1.5 and liquid to solid ratio of 20 (v/w)) was 26.1 ± 1.0%. The results showed that unrippen grape pomace pectin had degree of esterification of 51.6%, galacturonic acid content of 66.1%, emulsifying activity of 57.2%, and also showed favorable emulsion stability. The FT-IR spectrum confirmed the presence of esterified poly galacturonic acid structure in pectin sample. https://ijbse.ut.ac.ir/article_80011_1f1f9045cf99f3327faf39c0f28a8bc5.pdf