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Chardonnay grape pomace was evaluated as a source of pectin. A central composite design was used in order to determine the effect of pH, extraction time (Et) and liquid: solid ratio (LS) on the yield and uronic acid (UA) content of the pectins extracted using boiling HNO 3 solution. The optimized extraction condition to reach the maximum yield and UA was pH = 2.08, Et = 135.23 min and LS = 35.11 ml/g, resulting in theoretical yield of 12.8% and UA of 64.4%. The experimental yield of the pectic fraction obtained under the optimized conditions (GPOP) was 11.1% and the UA was 56.8%. GPOP had ~25% glucose. It was treated with α-amylase and amyloglucosidase, resulting in the fraction α-GPOP. The starch-free pectic fraction was composed of 63.5% UA, 7.8% rhamnose, 6.0% arabinose, 13.6% galactose and minor amounts of other neutral monosaccharides. It contained a low-methoxyl pectin (degree of methyl-esterification 18.1%) and had an average molar mass of 154,100 g/mol. It consisted of 55.7% homogalacturonan and 35.2% rhamnogalacturonan I (RG-I). NMR analyses suggest that RG-I portion of α-GPOP is highly branched by short chains or single residues of arabinose and galactose. Unlabelled Image • Chardonnay grape pomace was evaluated as a source of pectin by acid extraction. • Conditions for highest yield and uronic acid: pH 2, liquid:solid 35 ml/g, 135 min. • The polysaccharide obtained was purified by enzymatic treatment and characterized. • The pectic fraction had 56% HG, 35% RG-I, DM = 18.1% and M w = 154,100 g/mol. [ABSTRACT FROM AUTHOR]

A central composite experimental design was used to evaluate the influence of pH, extraction time and liquid:solid ratio on the yield and uronic acid content of the pectin from ponkan peel. The response surface methodology showed that the yield is positively influenced by lower pHs, longer extraction times and higher liquid:solid ratio, whereas the uronic acid content decreases with increasing extraction time. The conditions that resulted in the highest yield and highest uronic acid content were defined as pH 1.6, extraction time of 100 min and liquid:solid ratio of 36 mL/g. The pectin obtained under these conditions (PPOP) had an experimental yield of 25.6%, below the predicted theoretical value despite the good fit of the model (R 2  = 0.96) and the galacturonic acid content was 84.5%, in close agreement with the predicted theoretical value. PPOP was composed mainly of a homogalacturonan with degree of methyl esterification of 85.7% and a rhamnogalacturonan I region mainly branched by galactans. In addition, PPOP had a very low degree of acetylation (0.1%) and average molar mass of 80,650 g/mol, determined by light scattering. The results showed that ponkan peel may be used as a source of citrus pectin in the regions where this species is cultivated. [ABSTRACT FROM AUTHOR]

Cell wall polysaccharides from ponkan peel were investigated with the aim of gain knowledge about their potential for different applications and the use of ponkan peel as raw material for pectin extraction. The plant material was defatted using MeOH:CHCl 3 , pretreated with DMSO and then subjected to sequential extractions with cold and hot water, ammonium oxalate, HCl, Na 2 CO 3 , 2 M and 4 M NaOH in order to obtain polysaccharides. The polysaccharide fractions were analyzed by chemical, chromatographic and spectroscopic methods Cold and hot water-soluble pectins contained higher amounts of GalA and higher degrees of methyl-esterification (DM) than ammonium oxalate and HCl fractions. Na 2 CO 3 extraction provided non-esterified arabinose-rich pectins which formed gel in a dialysis step. NaOH solubilized hemicelluloses, composed mainly of xyloglucans, galactomannans and galactoglucomannans. The water-soluble fraction (WSP) was purified using α-amylase and amyloglucosidase and gave rise to the subfraction named α-WSP. The α-WSP was a pectin composed of HG and RG-I domains containing side chains of arabinans and short-chains of galactans, with low DM (39.4%) and M w of 1.615 × 10 5  g/mol. [ABSTRACT FROM AUTHOR]

Cacao pod husks, the main by-product from cocoa production, have been investigated for pectin isolation. In the present study, the rheological properties of two low-methoxyl (LM) pectins isolated from cacao pod husks using different extraction conditions were evaluated. One pectin was obtained from optimized conditions employing aqueous nitric acid as an extractant, and the other one was extracted with boiling water. Pectin gels (0.99% galacturonic acid equivalent, w/w) were prepared at pH 2.5–3.0 in the presence of 60% sucrose (w/w) and subjected to rheological analysis. Dynamic oscillatory experiments at 25 °C indicated that better gels were obtained at the lowest pH (2.5). Steady shear measurements revealed a shear-thinning behavior. The apparent viscosities of the samples increased as pH decreased. Gelation with calcium ions was not observed for either of the highly acetylated LM pectins analyzed. The rheological analysis results showed that despite their high acetyl content, LM pectins extracted by different methods from cacao pod husks were able to form gels at low pH under reduced water activity, suggesting a possible application in acidic products. [ABSTRACT FROM AUTHOR]

Abstract: Variables that influence the citric-acid extraction of pectins from cacao pod husk were examined. A screening study tested the main parameters influencing pectin yield and uronic acid content by a factorial fractional 33−1 design. Further, response surface methodology was applied using a central composite design to examine the effect of a greater region of variable values on pectin yield and uronic acid content. The yield was optimized by increasing the temperature and time. None of the variables had a significant effect on the uronic acid content, and there was lack of fit of the model to the uronic acid content. From the fitted model, extraction conditions with aqueous citric acid at pH 3.0 for 95 min at 95 °C provided a predicted yield of approximately 9.0 g/100 g dry cacao pod husks. The obtained experimental value for the yield was 10.1 ± 0.3 g/100 g dry cacao pod husks, with the pectins containing 65.1 ± 0.8 g uronic acid/100 g fraction, DE 40.3% and DA 15.9%. At 5 g/100 g aqueous solution, the fraction behaved as a concentrated solution and presented a non-Newtonian shear-thinning behavior, well described by Cross Model. Additionally, the fraction formed gels at acidic pH and high sucrose content. [Copyright &y& Elsevier]

Abstract: The composition of cacao pod husks (CPHs), the main waste product of cocoa production, and some of the characteristics of their water-soluble pectins were investigated. Milled and dried CPHs were submitted to hot aqueous extractions (50 and 100̊C, 90min, 1:25, w/v). The obtained fractions (labeled 50W and BW, respectively) yielded 7.5 and 12.6% pectins, respectively. The monosaccharide composition revealed the predominance of uronic acid, followed by galactose, rhamnose and arabinose, characteristic of pectins. Chemical and spectroscopic analyses (FT-IR and 13C NMR) showed that both fractions contained high acetyl contents (DA 29.0 and 19.2%, respectively) and are composed of low methoxyl homogalacturonans (DE 37.0 and 42.3%, respectively) with rhamnogalacturonan insertions carrying side chains containing mainly galactose. Rheological analyses were carried out with 50W and BW. Solutions of both fractions at 5% (w/v) had a non-Newtonian shear-thinning behavior, however that of 50W showed higher apparent viscosity than that of BW. Dynamic oscillatory analyses showed that 5% (w/w) 50W pectin had weak gel behavior whereas at the same concentration, BW pectin behaved as a concentrated solution. Although further investigations are required, CPH seems be a potential source of both pectins and other natural agents such as fibers and phenolics, and its use is particularly justified by growing environmental awareness. [Copyright &y& Elsevier]

Abstract: This study examined variables that influence the nitric acid-extraction of pectins from cacao pod husks. An initial screening study tested the main parameters influencing yield and uronic acid content by a factorial fractional 33−1 design. Additional studies used response surface methodology using a central composite design. Yield was optimized by increasing temperature. Uronic acid content was higher when pH is decreased and temperature is increased, or when pH is increased and temperature is decreased. To optimize both parameters, extraction conditions of pH 1.5 at 100°C for 30min provided a predicted yield and uronic acid content of approximately 9.5% and 80%, respectively. The obtained experimental value for the yield was 9.0±0.4%, the pectin presenting 66.0% uronic acid. Chemical and spectroscopic analyses showed that this pectin is mainly a homogalacturonan highly esterified and acetylated (DE 56.6%; DA 17.1%) with some rhamnogalacturonan insertions. [Copyright &y& Elsevier]

Abstract: Cupuassu (Theobroma grandiflorum, Schumann) is a Brazilian Amazonian fruit whose pulp contains volatile compounds that have been extensively studied. In this work, the pulp from fruits of cupuassu was ground, treated with MeOH–H2O, and defatted with p-Tol–EtOH. The residue (4% in relation to the fresh pulp) was submitted to sequential extractions with water, aqueous citric acid and aqueous NaOH, resulting in polysaccharide fractions with 0.3–15% yield. The main pectic fraction (7% yield) was obtained with water at 25°C (W-1 fraction) and was chosen to be better characterized. Chemical and spectroscopic analyses showed that W-1 is composed mainly of a homogalacturonan highly esterified (DE 53%; DA 1.7%) with some rhamnogalacturonan insertions, carrying side chains containing galactose and arabinose. [Copyright &y& Elsevier]