title: Physicochemical and in vitro antioxidant properties of pectin extracted from hot pepper (Capsicum annuum L. var. acuminatum (Fingerh.)) residues with hydrochloric and sulfuric acids.
abstract: BACKGROUND
  Transformation of hot pepper residues to value-added products with concomitant benefits on environmental pollution would be of great value to capsicum oleoresin manufacturers. Pectin, a soluble dietary fiber with multiple functions, from hot pepper residues was investigated in this study.
  
  
  RESULTS
  The extraction of hot pepper pectin using hydrochloric acid was first optimized using response surface methodology (RSM). The most efficient parameters for maximum hot pepper pectin yield (14.63%, dry basis) were a pH of 1.0, a temperature of 90 °C, an extraction time of 2 h and a liquid-to-solid ratio of 20 L g-1. The pectin was mainly composed of uronic acids, and the major neutral sugars were galactose and glucose. The structure of hot pepper pectin was characterized by homogalacturonan and rhamnogalacturonan I elements. The physicochemical properties of hot pepper pectin extracted by sulfuric acid and hydrochloric acid were further investigated. The content of protein and degree of esterification in hot pepper pectin extracted with sulfuric acid solution (SP) were higher (P < 0.05) than those in that extracted with hydrochloric acid solution (HP), while the mean molecular weight of SP was lower than that of HP. Compared with HP, SP exhibited higher viscosity and better emulsifying property.
  
  
  CONCLUSIONS
  Based on the yield and physicochemical properties of hot pepper pectin, hot pepper residues would be a new source to obtain pectin, and SP would be more preferred than HP. © 2017 Society of Chemical Industry.
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
authors.forename: Honggao
authors.initials: H
authors.lastname: Xu
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
authors.forename: Kedong
authors.initials: K
authors.lastname: Tai
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Wei
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Yuan
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
authors.forename: Yanxiang
authors.initials: Y
authors.lastname: Gao
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification*; D002212:Capsicum / Q000737:chemistry*; D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D006851:Hydrochloric Acid / Q000737:chemistry; D010368:Pectins / Q000737:chemistry* / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification*; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D013464:Sulfuric Acids; D010368:Pectins; C033158:sulfuric acid; D006851:Hydrochloric Acid
keywords: antioxidant activity; emulsifying property; hot pepper pectin; response surface methodology; viscosity