*4.2.4 Structural analysis*

The isolated pectin was structurally characterized using FT-IR, 1H-NMR, and XRD spectroscopies in comparison with commercial citrus pectin. FT-IR spectrum of the KBr-dispersed samples was recorded on a Bruker Tensor 27 spectrometer by 10 scans at a resolution of 4 cm−1 over 4000–600 cm−1. 1 H-NMR spectrum was collected on a 500 MHz Varian Unity Inova spectrometer by eight scans (24°C, 4.0 s). XRD pattern was recorded on a Philips diffractometer (10–80° as 2θ).

<sup>3</sup> Standard deviation.

<sup>4</sup> Refractive Index Detector.

#### *4.2.5 Functional characteristics*

The functional properties were measured using four methods including WHC, OHC, EC, and ES in comparison with commercial citrus pectin. WHC and OHC were measured according to Kazemi et al. [17] as the mass (g) of water or oil retained by 1.0 g of pectin sample (g/g). EC (24°C) and ES (1 and 30 days, 4°C and 24°C) of emulsions were measured according to Yapo et al. [24].

#### *4.2.6 Antioxidant assay*

The antioxidant capacity of pectin solutions was determined in concentrations of 0.1–5 mg/mL using three methods, including DPPH scavenging activity, ABTS scavenging activity, and reducing power assay in comparison with ascorbic acid, beta hydroxy acid (BHA), and commercial citrus pectin at similar concentrations. Also, the half maximal inhibitory concentration values of DPPH and ABTS scavenging activity for each sample were calculated and compared (the required concentration of antioxidant for scavenging the 50% of initial concentration of free radicals).

#### *4.2.7 Statistical analysis*

Response surface BBD was used to assess the effects of MAE process variables individually and interactively in terms of pectin yield (56–150 g kg−1) and the highest pectin yield. The experimental data was applied in a second-order polynomial model developed using multiple regression analysis. Also, in order to show a good agreement between the experimental and predicted data, Pareto ANOVA was used. According to the obtained results, a fitted developed model could explain the suitable relationship between process variables and response.

### **5. Conclusions**

In food industry, the functional properties of pectin are influenced by the source, methods, and conditions of extraction (time, pH, LSR, temperature, wave power and frequency, enzymes, and the integrated conditions). Novel extraction methods are focused in studies in order to reduce extraction time/solvent consumption and increase process efficiency/pectin yield. Agri-food wastes can be processed to produce valuable by-products like marketable pectin according to commercial standards. Their significant WHC/OHC and promising emulsifying properties make them as textural ingredients and emulsifiers in food products and pharmaceutical supplements [9]. The green chemistry extraction process for the valorization of industrial food processing waste should be designed based on circular economy concepts in order to increase its benefits [5]. However, further research is needed to understand the synergistic effect of multiple extraction factors using new techniques for the improvement of the productivity of industrial pectin processes from Iran's Agro waste (**Tables 1** and **2**).

#### **Studies published in Persian:**

Akbari-Adergani B, Zivari Shayesteh P, Pourahmad R. Evaluation of some functional properties of extracted pectin from pomegranate peel by microwave method. *Journal of Food Technology and Nutrition*. 2021;18:5–16 [In Persian].

Amanpour M, Asefi N. Effect of ultrasound time and acid type on the qualitative properties of extracted high methoxyl pectin from quince fruit. *Iranian Journal of Nutrition Sciences and Food Technology*. 2020;15:71–82 [In Persian].

Azadbakht M, Tabaey MH, Sabet Ahd Jahromi A. The comparison of various methods for extraction and isolation of pectin from *Citrus Decumana* Murry. *Journal of Tabriz University of Medical Sciences (Pharmaceutical Sciences)*. 2003;1:21–28 [In Persian].

Bahramipour M, Akbari-adergani B. Optimization of microwave-assisted extraction of pectin from peaspod by response surface method. *Journal of Food Science and Technology*. 2018;80:349–360 [In Persian].

Darvishi M, Yazdanpanah S. Evaluation and comparison of emulsion, rheological and spectroscopic properties of FT-IR extracted pectin from peel and cap of pumpkin. *Journal of Food Science and Technology*. 2020;17:149–162 [In Persian].

Ebrahimzadeh MA, Azadbakht M. (2006). Extraction of pectin and comparison of yield and degree of esterification and percentage of galacturonic acid in the skin of some citrus. *Journal of Mazandaran University of Medical Sciences*. 2006;16:52–59 [In Persian].

Fathi B, Maghsoudlou Y, Ghorbani M, Khomeiri M. Effect of pH, temperature and time of acidic extraction on the yield and characterization of pectin obtained from pumpkin waste. *Journal of Food Research (AGRICULTURAL SIENCE)*. 2012;22:465–475 [In Persian].

Haji Esmaelli F. Extraction of pectin from sugar beet pulp [master's thesis]. Tehran (Iran): Science and Research Branch. Islamic Azad University; 2002 [In Persian].

Hosseini SS, Khodaiyan F, Barazande S. Extraction and comparison of the physicochemical properties of pectin extracted from pineapple, samsuri and galia melon peels assisted by microwave. *Iranian Journal of Food Science and Nutrition*. 2017;11:71–80 [In Persian].

Jannat B, Oveisi MR, Sadeghi N, Behzad M, Behfar AAA, Hajimahmoodi M, et al. Determination of pectin in sunflower and its application in food industry. *Journal of Food Technology and Nutrition*. 2016;13:25–34 [In Persian].

Karimifard SM. Separation of valuable chemicals from citrus waste and conversion of the produced wastes to biogas [master's thesis]. Isfahan (Iran): Isfahan University of Technology; 2013 [In Persian].

Keramat J, Kabir GM, Ghenaati B. Qualitative and quantitative study of pectins extracted from the orange juice concentrate production process waste. *Agricultural Science and Technology and Natural Resources*. 2002;6:141–148 [In Persian].

Mesbahi GR, Jamalian J. Pectin extraction from sugar beet pulp and its application in food products. *Journal of Agricultural Science and Technology of Agriculture and Natural Resources, Water and Soil Science*. 2002;6:125–138. [In Persian].

Mirmajidi A, Babaei B. Extraction of pectin by pre-hydrolysis method from some commercial type of sugar beet. *Research in Agricultural Engineering*. 2007;9:103–114. [In Persian].

Mosayebi V, Emam-Djomeh Z, Tabatabaei Yazdi F. Optimization of extraction conditions of pectin by conventional method from black mulberry pomace. *Quarterly Journal of Food Science and Technology*. 2017;62:341–356 [In Persian].

Nateghi L. Optimization of extraction conditions of pectin from *Aloe Vera* leaf. *Food Technology and Nutrition*. 2021;18:95–115. [In Persian].

Nateghi L, Ansari S, Shahab Lavasani AR. Investigation of yield and physicochemical properties of pectin extracted from eggplant peel. *Food Science and Technology*. 2017;73:13–30 [In Persian].

Nateghi L, Ansari S. Investigation of yield and physicochemical properties of pectin extracted from eggplant cap. *Journal of Modern Food Technologies*. 2017;5:219–239 [In Persian].

Saberian H. Optimization of pectin extraction from orange waste by ohmic and enzymatic novel methods [Ph.D Thesis]. Tehrn (Iran): Tarbiat Modares University; 2017 [In Persian].

Zarei M. Effect of extraction temperature on qualitative characteristics extracted pectin from orange peel. 18th National Congress on Food Technology, Mashad, Iran; 2008 [In Persian].

#### **Studies published in English:**


#### **Table 1.**

*A collection of underlined Iran-affiliated studies for the reported results about pectin extraction procedures from Agri-food wastes.*

*Agricultural Pectin Extraction in Iranian Experimental Settings DOI: http://dx.doi.org/10.5772/intechopen.109935*


**Table 2.** *The experimental profiles of pectin extraction for some Iran's agricultural wastes [9].*

*Utilization of Pectin in the Food and Drug Industries*
