Comparative Studies of Combined Influence of Variables on the Esterification Degree of Pectin Extracted by Sulfuric Acid and Citric Acid

Jun Li,Ling Zhang,Jun-Fang Li,De-Qiang Li

doi:10.1155/2019/6313241

Jun Li, Ling Zhang + Show 2 more

Open Access

https://doi.org/10.1155/2019/6313241

Copy DOI

Abstract

The influence of extraction variables on degree of esterification (DE) of pectin was studied due to the significant effects of DE on the properties of the pectin-based functional biomaterials. The extracting agents (sulfuric acid and citric acid), pH value of extraction solution, extraction time, and temperature were selected to study the hydrolysis reaction of carboxylic acid ester by response surface methodology (RSM). The hydrolysis reaction occurred more violently in the weak organic acid solution than that in the strong inorganic acid solution. The DE was significantly influenced by pH of extraction solution, extraction time, and temperature through the analysis of variance. In addition, the values of DE reduced with the increasing of extraction temperature, lapse of time, and decreasing of pH value. What is more, the effects of extraction conditions on the yield, monosaccharide composition, content of protein, and ferulic acid were also studied. It is evident that the lower pH value contributed to higher extraction yield. The content of Total CH and GalA of pectin extracted by sulfuric acid were higher than that of pectin extracted by citric acid, and the content of monosaccharide showed an opposite trend.

Highlights

Pectin is a complex of polysaccharide which exists in the cell wall of almost all higher plants [1]
initial titre (It) is clear that the values of degree of esteri cation (DE) are generally higher than those of DEc. e fact may be caused by the hydrolysis reaction of carboxylic acid ester in the acidic solution [26]
It is well known that the acid could provide the proton to oxygen atom of carboxyl group and positive electricity of carbonyl carbon atoms improves as a result. en water play the role of the nucleophile to attack the carbonyl carbon in the acid-catalyzed hydrolysis reaction [27, 28]

Summary

Introduction

Pectin is a complex of polysaccharide which exists in the cell wall of almost all higher plants [1]. Due to gelling, emulsifying, thickening, and stabilizing properties, pectin has been widely used in the food industry to improve food products in texture, taste, and appearance [2]. Sugar beet pulp (SBP) is the by-product from sugar industry and has been proved to be the potential raw materials for pectin extraction. Nowadays many advanced methods, including ultrasonic-assisted extraction process [3], microwave-assisted extraction process [4], and electromagnetic-induced heating process, [5] have been developed to extract pectin from numerous raw materials [6, 7]. E chemical structure and the physico-chemical properties of pectin dominate its corresponding functional properties, including the gelling, emulsifying, thickening and stabilizing properties, and biological activity [2] Plenty of published data indicate that the extraction conditions signi cantly in uence the yield, degree of esteri cation (DE), and content of the monosaccharides and protein. e chemical structure and the physico-chemical properties of pectin dominate its corresponding functional properties, including the gelling, emulsifying, thickening and stabilizing properties, and biological activity [2]

Methods

Results

Conclusion