Characterisation of cell-wall polysaccharides from mandarin segment membranes
Coll-Almela, L. ; Saura-Lopez, D. ; Laencina-Sanchez, J. ; Schols, H.A. ; Voragen, A.G.J. ; Ros-García, J.M. - \ 2015
Food Chemistry 175 (2015). - ISSN 0308-8146 - p. 36 - 42.
hairy ramified regions - cross-flow filtration - pectolytic enzyme - citrus-fruit - pectins - degradation - extraction - skin - rhamnogalacturonase - populations
In an attempt to develop a process of enzymatic peeling of mandarin segments suitable for use on an industrial scale, the cell wall fraction of the segment membrane of Satsuma mandarin fruits was extracted to obtain a chelating agent-soluble pectin fraction (ChSS), a dilute sodium hydroxide-soluble pectin fraction (DASS), a 1 M sodium hydroxide-soluble hemicellulose fraction (1MASS), a 4 M sodium hydroxide-soluble hemicellulose fraction (4MASS) and a cellulose-rich residue (3.1, 0.9, 0.4, 0.7 and 1.6% w/w of fresh membrane, respectively). The ChSS pectin consisted mainly of galacturonic acid followed by arabinose and galactose. The DASS fraction contained less galacturonic acid and more neutral sugars than ChSS. Eighty-nine percent of the galacturonic acid present in the segment membranes was recovered in the above two pectin fractions. The two hemicellulosic fractions consisted of two different molecular weight populations, which also differed in their sugar composition. Arabinose, xylose, mannose, galactose and glucose were the main sugar constituents of these hemicellulose fractions. In addition to an (arabino)xylan and a xyloglucan, the presence of an arabinogalactan is suggested by the sugar composition of both hemicelluloses. The pectin fractions were also characterised by their degradability by the pectic enzymes polygalacturonase, pectinmethylesterase and rhamnogalacturonan hydrolase. However the degree of degradation of the pectin fractions by enzymes differed, and the amount of the polymeric materials resistant to further degradation and the oligomeric products also differed. Using pectic enzymes it is possible to obtain peeled mandarin segments ready to eat or for canning.
Post-harvest Proteomics and Food Security
Pedreschi Plasencia, R.P. ; Lurie, S. ; Hertog, W. ; Nicolai, B. ; Mes, J.J. ; Woltering, E.J. - \ 2013
Proteomics 13 (2013)12-13. - ISSN 1615-9853 - p. 1772 - 1783.
cell-wall proteome - peach fruit - chilling injury - botrytis-cinerea - tomato fruit - citrus-fruit - sugar-beet - wide characterization - gel-electrophoresis - seed-germination
To guarantee sufficient food supply for a growing world population, efforts towards improving crop yield and plant resistance should be complemented with efforts to reduce postharvest losses. Post-harvest losses are substantial and occur at different stages of the food chain in developed and developing countries. In recent years a substantially increasing interest can be seen in the application of proteomics to understand post-harvest events. In the near future post-harvest proteomics will be poised to move from fundamental research to aiding the reduction of food losses. Proteomics research can help in reducing food losses through (i) identification and validation of gene products associated to specific quality traits supporting marker-assisted crop improvement programs, (ii) delivering markers of initial quality that allow optimization of distribution conditions and prediction of remaining shelf life for decision support systems and (iii) delivering early detection tools of physiological or pathogen related post-harvest problems. In this manuscript, recent proteomics studies on post-harvest and stress physiology are reviewed and discussed. Perspectives on future directions of post-harvest proteomics studies aiming to reduce food losses are presented.