Alkali-based pre-treatment may prevent ochratoxin A in grapes

Date

2016-01-01

Author

Özcan Kabasakal, Süreyya

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

190
views

0
downloads

In traditional raisin production process in Turkey, one of the major raisin producers in the world, grapes undergo an alkali treatment prior to drying. This procedure involves dipping grapes in a potassium carbonate solution for 10-15 seconds to remove the wax layer on the surface to accelerate the drying process. In this study, we aimed to investigate the effect of alkali treatment on ochratoxin A (OTA), an important risk factor for grapes and grape-derived products. First, the stability of the OTA was examined under variable pH (4-12), ion type (Na+, K+), ionic strength (0.1-10%) and temperature (4-60 degrees C). Then, Aspergillus ochraceus contaminated grapes were treated with an alkaline solution and a subsequent OTA analysis was performed through a high performance liquid chromatography-fluorescence detection. OTA started to decompose at pH values exceeding 10.0. The degradation followed a first order kinetics. Although both sodium carbonate and potassium carbonate solutions were at the same alkali pH and they both triggered the OTA degradation at increasing concentrations, potassium carbonate was more effective even at low concentrations. Elevated temperatures were also found to effect degradation. The degradation rate constant at 40 degrees C was approximately 5 times greater than the one at 25 degrees C. Furthermore, OTA levels dropped up to 50% in contaminated grapes after the alkali treatment. Our results confirmed that the amide bond of OTA rapidly hydrolysed to a non-toxic ochratoxin-alpha and phenylalanine under strong alkaline conditions. The results suggest that the alkaline pre-treatment unintentionally offers a great advantage to reduce OTA levels in raisins and it could be a viable approach for other dried fruits through the application of good manufacturing practice.

Subject Keywords

Toxicology, Food Science, Public Health, Environmental and Occupational Health

URI

https://hdl.handle.net/11511/48735

Journal

World Mycotoxin Journal

DOI

https://doi.org/10.3920/wmj2015.2017

Collections

Department of Chemistry, Article

Suggestions

OpenMETU
Core

Surveys of aflatoxin B1 contamination of retail Turkish foods and of products intended for export between 2007 and 2009 Ulca, P.; Evcimen, M. K.; Senyuva, H. Z. (Informa UK Limited, 2010-01-01) Surveys were carried out between 2007 and 2009 to determine the aflatoxin B1 content of 3345 commercial Turkish foodstuffs supplied by producers for testing for their own purposes or for export certification. To simplify the reporting of data, foods were categorized as: 1, high sugar products with nuts; 2, nuts and seeds; 3, spices; 4, grain; 5, cocoa products; 6, dried fruit and vegetables; 7, processed cereal products; 8, tea; and 9, baby food and infant formula. Aflatoxin analysis was carried out by high...
Influence of alcohols on citric acid production by Aspergillus niger A-9 entrapped in polyacrylamide gels Yaykasli, KO; Demirel, G; Yasar, A (Elsevier BV, 2005-10-01) In this study, the production of citric acid has been achieved by using Aspergillus niger conidiaspores, entrapped in polyacrylamide gels, and the factors that affect this production have been investigated. On citric acid production the effect of starting sucrose concentration (100-180 g/l), the initial nitrogen concentration (0-0.3 g/l), the effect of the methanol concentration in 100ml feeding medium (0-6 ml), and finally the effect of ethanol concentration (0-6 ml) in 100 ml feeding medium were studied a...
Trace level determination of beryllium in natural and flavored mineral waters after pre-concentration using activated carbon KILINÇ, ERSİN; Bakirdere, Sezgin; YAMAN, MEHMET (Informa UK Limited, 2011-01-01) The concentrations of beryllium (Be) in natural and flavored mineral water samples were determined by flame atomic absorption spectrophotometer (FAAS) after pre-concentration based on the complexation of Be(+2) with a mixture of acetylacetone (pentane-2,4-dione) plus morin (3,5,7,2',4'-pentaoxyflavone) and adsorption on activated carbon. The adsorbed complex was eluted with 1.5 ml of 2.0 M HNO(3) and evaporated to dryness. After adding 1.5 ml of 2 M HNO(3) and centrifuging, Be in acid solution was determine...
A critical review of the specifications and performance of antibody and DNA-based methods for detection and quantification of allergens in foods Senyuva, Hamide Z.; Jones, Ivona Baricevic; Sykes, Mark; Baumgartner, Sabine (Informa UK Limited, 2019-01-01) Despite the availability of a large number of antibody and DNA based methods for detection and quantification of allergens in food there remain significant difficulties in selecting the optimum technique to employ. Published methods from research groups mostly contain sufficient detail concerning target antigen, calibration procedures and method performance to allow replication by others. However, routine allergen testing by the food industry relies upon commercialised test kits and frequently the suppliers...
Microcapsule characterization of phenolic powder obtained from strawberry pomace Çilek Tatar, Betül; Şümnü, Servet Gülüm; Öztop, Halil Mecit (Wiley, 2019-06-01) Strawberry pomace, waste of strawberry (Fragaria x ananassa) juice, is widely produced in food industry, and contains natural phenolic compounds. In this study, microencapsulation of phenolic powder obtained from strawberry pomace was achieved using different combinations of maltodextrin (MD) and gum arabic (GA). Microcapsules were prepared using a high‐speed homogenizer (HSH) and a high‐pressure homogenizer (HPH). During HPH, 50 and 70 MPa were chosen as pressures with different process cycles (3, 5, and 7...

Citation Formats

S. Özcan Kabasakal, “Alkali-based pre-treatment may prevent ochratoxin A in grapes,” World Mycotoxin Journal, pp. 517–523, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48735.