Download full-text


Available from: Sebastian Fernando Cavalitto, Sep 27, 2015
36 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Extracted sugar-beet pulp was studied as a source of galacturonic acid. For this purpose a commercial enzyme mixture (Pectinex® 100 l from Novo Nordisk) was used to degrade extracted sugar-beet pulp to galacturonic acid in high yields and at short retention times. Because sugar-beet is a very complex substrate with a varying, non-standardisable composition, the kinetics of this enzyme mixture were studied at first with citrus- and sugar-beet pectin as model substrates, in order to define a starting point for a comparison. The degradation of the citrus- and sugar-beet pectin was carried out in acetate buffer (pH 4) and the decomposition of extracted sugar-beet pulp in water (pH 4.4), with a view to an industrial application. It was found, that for all substrates no substrate inhibition, but a strong product inhibition is given. Therefore, the use of extracted sugar-beet (and other related compounds) can enzymatically yield only low concentrations of galacturonic acid.
    Enzyme and Microbial Technology 04/2004; 34(5-34):505-512. DOI:10.1016/j.enzmictec.2003.12.008 · 2.32 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The white part of citrus peel, the albedo, has a special role in water relations of both fruit and leaves from early on in fruit development. In times of drought, this tissue acts as a water reservoir for juice sacs, seeds and leaves. When water was injected into the albedo, free water was undetectable using magnetic resonance imaging. Microscopy showed tightly packed cells with little intercellular space, and thick cell walls. Cell wall material comprised 21% of the fresh albedo weight, and contained 26.1% galacturonic acid, the main constituent of pectin. From this, we postulated that pectin of the cell wall was responsible for the high water-binding capacity of the immature lemon albedo. Cell wall material was extracted using mild procedures that keep polymers intact, and four pectic fractions were recovered. Of these fractions, the SDS and chelator-soluble fractions showed viscosities ten and twenty times higher than laboratory-grade citrus pectin or the other albedo-derived pectins. The yield of these two pectins represented 28% of the cell walls and 62% of the galacturonic acid content of immature lemon albedo. We concluded that, from viscosity and abundance, these types of pectin account for the high water-binding capacity of this tissue. Compositional analyses showed that the two highly viscous pectic fractions differ in galacturonic acid content, degree of branching and length of side chains from the less viscous albedo-derived pectins. The most striking feature of these highly viscous pectins, however, was their high molecular weight distribution compared to the other pectic fractions.
    Journal of Plant Physiology 05/2004; 161(4):371-9. DOI:10.1078/0176-1617-01275 · 2.56 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new method for the production of pectin from citrus peel was developed. For this purpose, a microorganism which produces a protopectin-solubilizing enzyme was isolated and identified as a variety of Trichosporon penicillatum. The most suitable conditions for the pectin production were determined as follows. Citrus (Citrus unshiu) peel was suspended in water (1:2, wt/vol), the organism was added, and fermentation proceeded over 15 to 20 h at 30 degrees C. During the fermentation, the pectin in the peel was extracted almost completely without macerating the peel. By this method, 20 to 25 g of pectin was obtained per kg of peel. The pectin obtained was special in that it contained neutral sugar at high levels, which was determined to have a molecular weight suitable for practical applications.
    Applied and Environmental Microbiology 05/1980; 39(4):908-12. · 3.67 Impact Factor
Show more