Isolation of Pectin from Clementine Peel: A New Approach Based on Green Extracting Agents of Citric Acid/Sodium Citrate Solutions

Abstract

A new approach to extract pectin from clementine peel using citric acid/sodium citrate solutions (CSS) at different pHs as green extracting agents was proposed. In this study, the effects of extraction temperature (65–85 °C), CSS pH (2–8), and extraction time (1–3 h) on the extraction yield, uronic acid content, and degree of methyl esterification (DE) of the clementine peel pectin (CMP) were systematically evaluated by response surface methodology (RSM). Compared with traditional methods, the CMP extracted by this new approach was of higher pectin yield (19.90–34.94%) and uronic acid content (44.96–65.11%), as well as a wide DE value (11.05–84.71%). These functional properties of CMP were mainly determined by the CSS pH and extraction temperature. In comparison with commercial citrus pectin (CP), the extracted CMPs showed lower protein contents and larger molecular weights. The analysis of monosaccharide compositions showed that the high- and low-methyl-esterified CMPs were dominated by homogalacturonans and rhamnogalacturonan-I, respectively. The structural differences between high- and low-methyl-esterified CMPs were identified by their FTIR spectra. Especially, an excellent gel-forming capacity was found in low-methyl-esterified CMP solutions since their rheological behaviors were highly sensitive to low pH and the presence of Ca2+.

Encapsulation of Lactobacillus in Low-Methoxyl Pectin-Based Microcapsules Stimulates Biofilm Formation: Enhanced Resistances to Heat Shock and Simulated Gastrointestinal Digestion

“…Low-methoxyl CMPs were prepared as described in our previous study. 13 Briefly, dried clementine peel powder (10 g) was mixed with 250 mL of 0.1 M citric acid/sodium citrate solutions at pH 6 and 8, respectively. The mixtures were then placed in a shaking water bath at 65 °C for 2 h for pectin extraction.…”

“…They show excellent Ca 2+ -induced gelling capacity, and the rheological behavior of their solutions is sensitive to low pH. 13 Inoculum Preparation. Three Lactobacillus strains including L. acidophilus LMG9433 T , L. casei LMG6904 T , and L. rhamnosus LMG25859 were used in this study.…”

“…In our previous study, we extracted two low-methoxyl pectins from clementine peel using a green extraction agent of citric acid/sodium citrate solution. 13 These low-methoxyl clementine peel pectins (CMPs) exerted great Ca 2+ -induced gelling capacity that can be potentially applied to encapsulation. To verify this, we used these two low-methoxyl pectins as coating materials for bacterial encapsulations of three Lactobacillus strains (Lactobacillus acidophilus LMG9433 T , Lactobacillus casei LMG6904 T , and Lactobacillus rhamnosus LMG25859).…”

Extraction of Pectin from Satsuma Mandarin Peel: A Comparison of High Hydrostatic Pressure and Conventional Extractions in Different Acids

“…Mineral acid extraction has the characteristics of high acidity and strong corrosion, which may cause degradation of pectin and environment pollution [11]. Furthermore, the use of mineral acids may introduce toxic elements into the final products [14]. In recent years, scholars have reported that organic acids with chelating properties had the advantages of mild extraction and less degradation of pectin.…”

New electrolyte beverages prepared by the citrus canning processing water through chemical improvement

“…It is hypothesized that if acid such as citric acid and alkali such as KOH can be introduced into the acid and alkali treatments, the segment membrane can be fully removed, the improved acid and alkali processing water can be mixed without salty taste and rich in electrolytes, which has the potential to be prepared into electrolyte beverages. There have been many studies using citric acid and KOH to extract pectin from the skins and pomaces of various fruits ( He et al, 2021 , Mierczyńska et al, 2017 , Yang et al, 2018 ). The principle of segment membrane removal is to break the adhesion of pectin, cellulose and hemicellulose so that the pectin can be dissolved and the structure of the segment membrane is destroyed.…”