کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
605310 880343 2013 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Butternut and beetroot pectins: Characterization and functional properties
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Butternut and beetroot pectins: Characterization and functional properties
چکیده انگلیسی

The physicochemical characteristics and functional properties of butternut (Cucumis moschata Duch. ex Poiret) and beetroot (Beta vulgaris L. var. conditiva) pectins obtained by enzymatic extraction from by-products of vegetable processing have been evaluated. The molecular mass distribution was determined using Gel Permeation Chromatography using light scattering, refractive index and UV detectors and the samples were found to be highly heterogeneous and polydisperse. Mw values of 136,000 and 1,309,000 g/mol were determined for butternut and beetroot pectins respectively. Butternut pectin had a high degree of methyl esterification. In the presence of high concentrations of sugar and at low pH, this pectin did not form gels but instead produced viscous solutions. Solutions showed pseudoplastic flow behaviour with a shear thinning index of 0.68 as determined from the Power law model. Beetroot pectin had a low degree of methyl esterification and formed gels with addition of Ca2+ at concentrations of 10 mg/g pectin or higher. The maximum value of the storage modulus was obtained at a Ca2+/GalA ratio of 0.25. The thermal stability of gels suggested that hydrogen bond interactions prevailed in the absence of Ca2+, whereas electrostatic junction zones increasingly developed between pectin chains as the calcium concentration increased. Aqueous solutions of butternut and beetroot pectins significantly reduced surface tension and both samples were able to form stable oil-in-water emulsions. It was found that protein and/or polyphenol – rich fractions present in the pectins adsorbed at the oil–water interface and were responsible for the emulsification properties.

Figure optionsDownload as PowerPoint slideHighlights
► Characterization of pectins extracted from by-products of butternut and beetroot.
► Weight average molecular masses and rheological behaviour.
► Their surface tension and emulsifying activity were also studied.
► The isolated pectins could be useful as food additives.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Food Hydrocolloids - Volume 31, Issue 2, June 2013, Pages 172–182
نویسندگان
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