Extraction, structure, and emulsifying properties of pectin from potato pulp

Abstract

Effects of HCl, H₂SO₄, HNO₃, citric acid, and acetic acid on the yield, structure, and emulsifying properties of potato pectins were investigated. Results showed that the highest yield (14.34%) was obtained using citric acid, followed by HNO₃ (9.83%), HCl (9.72%), H₂SO₄ (8.38%), and acetic acid (4.08%). The degrees of methylation (37.45%) and acetylation (15.38%), protein content (6.97%), and molecular weight (3.207 × 10⁵ g/mol) were the highest for pectin extracted using acetic acid, and (galactose + arabinose)/rhamnose was 33.34, indicating that it had a highly branched rhamnogalacturonan I domain. Fourier transform infrared spectroscopy showed a specific absorbance peak at 1064 cm^-1, which corresponds to the acetyl groups in potato pectins. SEM showed that all potato pectins are morphologically different. The emulsifying activity (EA, 44.97%-47.71%) and emulsion stability (ES, 36.54%-46.00%) of the pectins were influenced by acid types, and were higher than those of commercial citrus and apple pectin.

Keywords: Acetic acid (PubChem CID:176); Acid extraction; Citric acid (PubChem CID:311); Emulsifying properties; Ethanol (PubChem CID:702); Hydrochloric acid (PubChem CID:313); Nitric acid (PubChem CID:944); Pectin; Potato pulp; Sodium bisulfite (PubChem CID:23665763); Sodium hydroxide (PubChem CID:14798); Structure; Sulfuric acid (PubChem CID:1118); d-galactose (PubChem CID:6036); d-galacturonic acid (PubChem CID:439215).