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Bibliographic record number: 724002

Journal

Authors: Branka, Levaj; Korina, Herceg; Sanela, Kićanović; Danijela, Bursać Kovačević; Maja, Repajić; Draženka, Komes
Title: Determination of pectolytic enzymes activity in various fruits and vegetables
Source: Proceedings of 8th International Congress of Food Technologists, Biotechnologists and Nutritionists / Frece, Jadranka (ed). - Zagreb : Croatian Society of Food Technologists, Biotechnologists and Nutritionists) , 2014. 87-92 (ISBN: 978-953-99725-6-9).
Meeting: 8th International Congress of Food Technologists, Biotechnologists and Nutritionists
Location and date: Opatija, Hrvatska, 21-24.10.2014.
Keywords: enzyme activity ; pectin methylesterase ; polygalacturonase ; fruits
Abstract:
The aim of this study was to improve sensitivity and accuracy of certain assays for determination of polygalacturonase (PG) and pectin methylesterase (PME) activity found in literature which would be applicable for various fruits and vegetables. Sensitivity and accuracy of methods found in the literature was tested and improved with fresh carrots, after which adapted methods were tested on several fruit species peaches, apricots, raspberries, and tomatoes, in their consume ripeness and after 3 day storage at 20 °C. Spectrophotometric method was used for determination of PG activity where enzyme activity was measured by colorimetrical quantification of galacturonic acid residues liberated by PG from polygalacturonic acid. A colorimetric reagent as well as the reaction conditions (temperature and incubation time) used in this assay corresponds to those previously established, presently adapted in order to obtain measurable results for activity in carrot. Literature indicates sample incubation at 37 ° C for 1 hour and colorimetric determination of reducing sugar by orcinol-sulphuric acid reaction, but according to obtained results carbazole method for determination of galacturonic acid residues and sample incubation at 48 °C for 2 hours was found as the more suitable PG assay. PME activity was assayed by titrimetric determination, and it was quantified as carboxyl groups formed by the hydrolysis of methyl esters of pectin in a certain time interval. Method which defines reaction time interval, what means retaining reaction mixture under pH 7.5 during 30 min was shown to be optimal for PME activity determination. Obtained results are in accordance with literature data, and show that proposed assays could be successfully used in order to evaluate PME and PG activity in carrots as well as in other fruits and vegetables. Obtained results confirmed that pectolytic enzyme activity varies depending on fruit and vegetables type and ripeness.
Type of meeting: Poster
Type of presentation in a journal: Full-text (1500 words and more)
Type of peer-review: International peer-review
Project / theme: 058-0580696-2728
Original language: ENG
Category: Znanstveni
Research fields:
Food processing technology
Contrib. to CROSBI by: Danijela Bursać Kovačević (dbursac@pbf.hr), 27. Lis. 2014. u 16:50 sati



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