• G. Van Ranst
  • V. Fievez
  • M. Vandewalle
  • J. De Riek
  • E. Van Bockstaele

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The goal of this paper was, first, to study the effect of red clover polyphenol oxidase (PPO) activity on protein-bound phenols and measured lipase activity in vitro and, second, to study the effect of PPO activation, measured as an increase in protein-bound phenols, as a result of degrees of damaging (not damaged, crushed, and freeze/thawed) of red clover before wilting on measured enzyme activity and in vitro lipid metabolism when incubated in a phosphate buffer. There was a positive relation between PPO activity and the occurrence of protein-bound phenols with a concomitant decrease in measured lipase activity, indicating a possibility to a direct inhibition of enzymes as a result of protein-bound phenols. Furthermore, damaging can activate PPO in red clover, measured as an increase in protein-bound phenols during wilting [0.7-20.6 nmol of tyrosine equiv (mg of protein)(-1)], again with a concomitant decrease in measured lipase activity [41.3-20.3 mu mol of p-nitrophenyl butyrate (PNPB) min(-1) (mg of protein)(-1)]. Lipid metabolism during incubation of these forages in a phosphate buffer with ascorbic acid was only influenced by damaging when wilted for 24 h, with a lower lipolysis in crushed and freeze/thawed (52.9 and 32.6%, respectively, after 8 h of incubation) material compared to all other treatments (on average 60.4% after 8 h of incubation)
Original languageEnglish
JournalJournal of Agricultural and Food Chemistry
Volume57
Issue number15
Pages (from-to)6611-6617
Number of pages7
ISSN0021-8561
DOIs
Publication statusPublished - 2009

    Research areas

  • ACID, ACTIVATION, ADDITIVES, AGRICULTURE, Belgium, clover, ENZYME-ACTIVITY, enzymes, fatty acids, FATTY-ACID-COMPOSITION, Food, FORAGE, FORAGES, In vitro, IN-VITRO, INHIBITION, L., lipid metabolism, LIPID-METABOLISM, LIPOLYSIS, metabolism, Occurrence, PHENOLS, POLYPHENOL OXIDASE, PROTEINS, PROTEOLYSIS, PURIFICATION, Red clover, RED-CLOVER, SCIENCE, SILAGE, TECHNOLOGY, USA

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