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Determination of fruit content in strawberry jam on the basis of analyses of selected chemical marker s

Determination of fruit content in strawberry jam on the basis of analyses of selected chemical marker s. Objectives to resume the chemometric methods for the fruit content determination in strawberry jams to optimise the method of HPLC determination of strawberry anthocyanidins.

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Determination of fruit content in strawberry jam on the basis of analyses of selected chemical marker s

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  1. Determination of fruit content in strawberry jam on the basis of analyses of selected chemical markers • Objectives • to resume the chemometric methods for the fruit content determination in strawberry jams • to optimise the method of HPLC determination of strawberry anthocyanidins

  2. Czech legislation • Decree 332/1997 (Novelised version 92/2000) • defines weigh part offruit • jam extra - 450 g fruit per 1kg product • jam common - 350 g fruit per 1kg product • strawberry jam (single sort) – 400 g fruit per 1kg product minimal refractive solid content • strawberry jam – 60% • sterilized strawberry jam – 50% • low-energy jam – max. 40% • Law No 634/1992 on protection of consumer • Law No 110/1997

  3. refractive solid refractometer K, malic and citric acid capillary isotachophoresis, electrophoresis phosphor spectrophotometry formol number according to RSK sucrose, glucose, fructose and sorbitol HPLC anthocyanidins spectrophotometry Markers and methods

  4. Result and discussion Sample: 1 – sterilized strawberry jam 2 - strawberry jam 3 - low-energy jam 4 – strawberry 5 - home-made jam

  5. Strawberry (data from literature)

  6. Values calculate on 100% fruit content

  7. Many factors affecting the accuracy of fruit content estimation • variability of raw material • change during processing and storage • analytical methods • product prescription (e.g. addition of acid)

  8. Method for determination anthocyanidins by HPLC conditions of HPLC method column : NOVA – PAK R C18, 4 μm 3.9 mm x 300mm mobil phase : water : acetonitrile : formic acid (81 : 9 : 10 v/v) flow rate : 1ml/min injection : 20 μl detection : 525 nm calibration : external standard (pelargonidine chloride)

  9. Sample preparation • sample mixture with solution (methanol : acetic acid : water 25 : 1 : 24) • filtration • vacuum evaporation • hydrolysis (HCl) • purifying of sample on the cartridge SEP-PAC C18 • vacuum evaporation • dissolve sample and determination on HPLC

  10. Result and discussion Affect many factors for determination of anthocyanidins - variability of raw material - strawberry cultivar - physiological state of plant and fruit - agriculture conditions - anthocyanidins are quite unstable affecting factors -structure of molecule - presence of some enzymes - pH - temperature - oxygen presence - irradiation - some substances influence anthocyanidins´ colour (e.g. ascorbic acid, SO2, phenols)

  11. Conclusions • continue with collecting of an other kinds of samples and their measuring • trying to use some another markers • trying to optimise a method for a measuring of content of anthocyanidins

  12. Thank you for your attention

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