Diamond synthesis by high-velocity thermal spray: The laboratory analogue of a meteorite impact
- PDF / 319,188 Bytes
- 5 Pages / 595.276 x 793.701 pts Page_size
- 64 Downloads / 160 Views
Contents lists available at SciVerse ScienceDirect
Food Chemistry journal homepage: www.elsevier.com/locate/foodchem
Analytical Methods
Validation of a HPLC method for simultaneous determination of main organic acids in fruits and juices Rodrigo Scherer a, Ana Cecília Poloni Rybka a, Cristiano Augusto Ballus a, Adriana Dillenburg Meinhart a, José Teixeira Filho b, Helena Teixeira Godoy a,⇑ a b
Department of Food Science, Faculty of Food Engineering, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil Faculty of Agricutural Engineering, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil
a r t i c l e
i n f o
Article history: Received 21 December 2009 Received in revised form 8 September 2011 Accepted 25 March 2012 Available online 13 April 2012 Keywords: Liquid chromatography Organic acids Method validation Fruit juices Ascorbic acid stability
a b s t r a c t A liquid chromatographic method for fast and simultaneous determination of tartaric, malic, ascorbic and citric acids was validated for further application to fruits and juices. Moreover, the organic acids content of commercial samples of fruits and juices were evaluated, as well as the ascorbic acid stability during the storage. Determination of organic acids was carried out using a liquid chromatograph coupled to a diode array detector, with reversed phase (C18 column) and isocratic elution with 0.01 mol L 1 KH2PO4 (pH = 2.60) mobile phase. The validation parameters showed efficiency, adequate linearity, relative standard deviation values between 0.4% and 2.3% (n = 10) for repeatability and from 1.2% to 5.0% (n = 18) for reproducibility, limits of detection (LD) were between 0.03 and 3.31 lg mL 1 and quantification (LQ) were between 0.10 and 11.03 lg mL 1, recovery rates were between 82% and 110%, for two levels. In addition, the method is fast (10 min) and generates low and non-toxic residues. The values found for vitamin C were about 10 times above the values declared at the package. Ready to drink juices have a composition similar to the fruit, concerning to organic acids, except for the powder juice, in which only ascorbic and citric acids were found, for all tastes. After opening the package, a decrease of 14.0% and 27.0% in ascorbic acid content was observed for orange powder and ready to drink juices, respectively. Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction Organic acids are natural compounds in fruits and vegetables. The nature and concentration of the organic acids in fruits are of interest because of their important influence on the organoleptic properties and stability of fruit juices. The organic acid profile and concentration in fruits and vegetables depends on factors such as species, soil and stress conditions to which the fruit was submitted (Jones, 1998). They are also used extensively as food additives in the manufacture of beverages, fruit and vegetable drinks and juices. The main acids used to enhance beverages are citric, malic and tartaric as acidulants and ascorbic as an antioxidant. Citrus j
Data Loading...
