Yield, Esterification Degree and Molecular Weight Evaluation of Pectins Isolated from Orange and Grapefruit Peels under Different Conditions

Abstract

Orange (Citrus sinensis) and grapefruit (Citrus paradise) peels were used as a source of pectin, which was extracted under different conditions. The peels are used under two states: fresh and residual (after essential oil extraction). Organic acid (citric acid) and mineral acid (sulfuric acid) were used in the pectin extraction. The aim of this study is the evaluation the effect of extraction conditions on pectin yield, degree of esterification “DE” and on molecular weight “Mw”. Results showed that the pectin yield was higher using the residual peels. Moreover, both peels allow the obtainment of a high methoxyl pectin with DE >50%. The molecular weight was calculated using Mark-Houwink-Sakurada equation which describes its relationship with intrinsic viscosity. This later was determined using four equations; Huggins equation, kramer, Schulz-Blaschke and Martin equation. The molecular weight varied from 1.538 x1005 to 2.47x1005 g/mol for grapefruit pectin and from 1.639 x1005 to 2.471 x1005 g/mol for orange pectin.

Modulation of Calcium Oxalate Crystal Growth and Protection from Oxidatively Damaged Renal Epithelial Cells of Corn Silk Polysaccharides with Different Molecular Weights

“…High-intensity ultrasonic energy may destroy some chemical bonds of the polysaccharides, resulting in decarboxylation reaction [53,54]. Moreover, linear CSP molecules with galacturonic acid undergo different degrees of esterification, and the degree of esterification is high when the molecular volume is small [55]. Therefore, the content of -COOH in polysaccharides with low molecular weight (such as CSP4 and CSP5) decreases again Figure 13.…”

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

“…As can be seen in Figures 3 and 4, the variation trend of DEc conforms with DEs with the alteration of independent variables. To summarize, the increasing of extraction temperature, time, and concentration of acid contributes to the low-ester pectin [36]. Figure 3(c) shows that the DEs changed more obviously at high extraction temperature than that at low extraction temperatures.…”

Structural, physicochemical and emulsifying properties of sweet potato pectin treated by high hydrostatic pressure and/or pectinase: a comparative study

“…Mw, DE, DM, and DA values As presented in Table 1, the Mw of natural sweet potato pectin was 7.53 × 10 5 g mol −1 , it was higher than that of grapefruit (1.54 × 10 5 -2.47 × 10 5 g mol −1 ) and orange pectin (1.639 × 10 5 -2.47 × 10 5 g mol −1 ), while lower than that of potato pectin (18.19 × 10 5 g mol −1 ). 13,16 The Mw of sweet potato pectin was decreased after modification, and the lowest Mw (0.05 × 10 5 g mol −1 ) was obtained by HHP-assisted E treatment, followed by E treatment (0.31 × 10 5 g mol −1 ). These results are comparable to those of previous studies, which showed that the Mw of sugar beet pulp pectin and potato pectin decreased upon application of HHP.…”