ORIGINAL ARTICLE Extraction and characterization of pectin from pomelo peel and its impact on nutritional properties of carrot jam during storage Manik Chandra Roy 1 | Majbaul Alam 1 | Abu Saeid 1 | Bijoy Chandra Das 1 | Md. Biplob Mia 1 | Md. Atikur Rahman 1 | Jong Bang Eun 2 | Maruf Ahmed 1,2 1 Department of Food Processing and Preservation, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh 2 Department of Food Science and Technology and BK 21 Plus Program, Graduate School of Chonnam National University, Gwanju, South Korea Correspondence Dr. Maruf Ahmed, Department of Food Processing and Preservation, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh. Email: maruffpp@gmail.com Abstract Pectin was extracted using 0.1 N HCl at 90 8C for 120 min at pH 1.5 and 2.0 from pomelo peel and characterized in this study. Influence of various concentrations of extracted pomelo peel pec- tin on physicochemical, bioactive compounds, color, and sensory attributes of carrot jam during storage was also studied. Pectin extracted at pH 2.0 had higher ash content, equivalent weight, and total anhydrouronic acid content than that extracted at pH 1.0. Extracted pomelo peel pectin was categorized as high-methoxyl pectin based on the degree of esterification. The b-carotene and total phenol content were increased in jam after 90 days of storage. Ascorbic acid content decreased with increasing storage period. Jam prepared using commercial pectin had higher DE values than jam prepared using pomelo peel pectin. Physico-chemical properties were influenced by pectin concentrations and storage time. Overall acceptability was similar for all samples on the basis of sensory evaluation. The results showed that pomelo peel might be used as a rich source of pectin and pomelo peel pectin could be used as an alternative to commercial pectins for carrot jam preparation. Practical applications Pectin is one of the main ingredients for jam and jelly making. Citrus fruits are main sources of pectin. Usually pomelo peels are discarded as waste materials. However, it could be a good source of pectin. In this article, pectin was extracted from pomelo peel and its application was observed as carrot jam during storage. Therefore, it can be concluded that extraction of pectin from pomelo peel might be used as an alternative to commercial pectin for carrot jam preparation. 1 | INTRODUCTION The most widely cultivated citrus fruits are the following: orange, lemon, lime, mandarin, grape fruit, and pomelo. Citrus fruit pulp consists of 60– 65% peels, 30–35% segment, pulp, and 0–10% seeds (Afshar & Naser, 2008). Citrus by-products are considered as rich sources of phytochemi- cals, pectin, and dietary fibers (Afshar & Naser, 2008). Pectin is the methylated ester of polygalacturonic acid, which contains 1,4-linked a-D-galacturonic acid residues (Mesbahi, Jamaliana, & Farahnaky, 2005). Pectin can be divided into two types based on the degree of esterifica- tion (DE): high-methoxyl pectin (DE > 50%) and low-methoxyl pectin (DE < 50%) (Mesbahi et al., 2005). The main sources for commercial pec- tin production are apple pomace and citrus peels (Mesbahi et al., 2005). Pectin can generally be extracted using various acids: citric acid, oxalic (Koubala et al., 2008), hydrochloric (Kulkarni & Vijanand, 2010), nitric (Constenla, Ponce, & Lozano, 2002), and sulfuric acid (Garna et al., 2007), which are regarded as conventional acids for extraction (Yapo, 2009). Sulfuric, hydrochloric, and nitric acids are cheap mineral acids. Among these, hydrochloric acid is recommended as the best sol- vent to extract pectin (Kalapathy & Proctor, 2001). High strength acid has the ability to solubilize the protopectin from the albedo. Lower pec- tin yield was obtained after using water and oxalate as chelating agents, as compared with that obtained from acid extraction (Methacanon, Krongsin, & Gamonpilas, 2014). Hot acid extraction (HCl) of pectin yielded a high anhydrogalacturonic acid content and had a low degree of methoxyl esterification (Yapo & Koffi, 2006). Kulkarni and Vijanand (2010) and Methacanon et al. (2014) found that pectin yield was higher, but methoxyl content and equivalent weight values were lower, at high temperature and lower pH than the values observed at lower tempera- ture and higher pH. An increase in acid strength (that is, decreasing pH) J Food Process Preserv. 2017;e13411. https://doi.org/10.1111/jfpp.13411 wileyonlinelibrary.com/journal/jfpp V C 2017 Wiley Periodicals, Inc. | 1 of 9 Received: 27 November 2016 | Revised: 17 May 2017 | Accepted: 3 June 2017 DOI: 10.1111/jfpp.13411