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The effect of ripening and storage on peach pectin and gel strength of related jams.

Author(s) : LEVAJ B., DRAGOVIC-UZELAC V., DANCEVIC A., et al.

Type of article: Article

Summary

Peaches were harvested in three stages of ripeness (threshold-mature, firm-ripe and ripe). Firm-ripe peaches were stored for 9 days at 4 and 22 °C. The amount of water-soluble, oxalate-soluble and alkali-soluble pectin were extracted and quantitatively determined as galacturonic acid, neutral sugars were determined as glucose. Jams were made with all peach samples as well as gels from extracted fractions. Gel strength of jams and gels was measured. Dry matter, sugar composition (amount of sucrose and reducing sugars) and pH value were determined and very little change was found during the ripening period and storage, too. Alkali-soluble fraction was more abounding than water-soluble fraction. The oxalate-soluble pectic fraction was found to be a minor fraction in all peach samples. The amount of total pectin and the amount of alkali-soluble pectin fraction dropped markedly after the 1st stage of ripening, after the 2nd day of storage at 22 °C and slightly after the 6th day of storage at 4 °C. It seems that the amount of alkali-soluble pectic fraction in peaches is responsible in producing peach jams according to gel strength.

Details

  • Original title: The effect of ripening and storage on peach pectin and gel strength of related jams.
  • Record ID : 2004-1815
  • Languages: English
  • Source: Acta Aliment. - vol. 32 - n. 4
  • Publication date: 2003/12
  • Document available for consultation in the library of the IIR headquarters only.

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