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Graphical abstract Highlights • Sugar acid-mediated pectin isolation instigates environmental-friendly technology. • This method negates the use of mineral acids for extraction. • The extracted pectin exhibited higher galacturonic acid content. • The extracted pectin was found to be a LM pectin with lower DE. Abstract Cocoa husks were used as the source for the pectin extraction by sugar acid treatment. A full factorial design was applied to screen the independent variables influencing the yield and uronic acid content. Followed by response surface methodology (RSM) was conducted using central composite design to optimize the extraction conditions. The optimized extraction condition was denoted as pH 2.5/95 °C/45 min. The yield and the uronic acid content of the extracted pectin was determined as 4.2 ± 0.12% and 74.5 ± 0.3% respectively. The extracted pectin was proved to be low methoxy pectin (LM pectin) with an 8.1% degree of esterification (DE). The pectin solutions showed shear thinning behaviour which was explicated by Williamson model. This work promotes environmentally friendly technology for pectin isolation. [ABSTRACT FROM AUTHOR]

The article assesses the energy use of solid biofuels (wheat and rape straw) and their blends with suitable additives (cocoa husks, brown coal and coal sludge). The elemental and stoichiometric analysis evaluates their suitability for energy recovery. Furthermore, thermal emission characteristics in automatic hot water boiler VERNER A251 are observed. The results of thermal emission measurements show that all samples meet the requirements of the Directive No. 13/2006 for carbon monoxide (2,000 mg/m3). The average nitrogen oxides emission concentrations exceed emission limits compared with the Directive No. 13/2006 (250 mg/m3) for all samples of solid biofuels. One reason is the high temperature in the combustion chamber that increases combustion temperature and results in high temperature of nitrogen oxides. Another problem is carbon monoxide that depends on the coefficient of excess air. The value of this coefficient drops under its optimum (2.5) and subsequently follows an increasing trend.

Highlights: [•] Pectin was extracted from cocoa husks, a processing waste from the cocoa industry. [•] Citric acid is the most efficacious matrix for pectin extraction from cocoa husks. [•] Low methoxyl pectin from cocoa husks was obtained using water or hydrochloric acid. [Copyright &y& Elsevier]

Abstract: Cocoa husks, a by-product of cocoa processing, were investigated as a source of pectins. Preliminary results of pectin recovery and characterization are shown; they constitute the first part of a study for the optimization of pectin extraction from this by-product. Husks of two different origins (Ghana and Venezuela) were used whole or minced and pectins were extracted under various conditions (pH 7.0, 4.0, 2.5, 1.5 and 1.0; extraction periods 1–3h): the highest yield is obtained with minced husks after 1h of extraction at pH 2.5. A preliminary characterization of pectins, in terms of methyl and acetyl ester contents, was also carried out in order to investigate the influence of different extraction conditions on the chemical composition of the extracts. [Copyright &y& Elsevier]