scholarly journals Determination of Anthocyaninsin Red Grape Juices Made From Different Varieties by HPLC

2017 ◽  
Vol 2 (5) ◽  
pp. 2720-2729
Author(s):  
İlkay Türkmen Özen ◽  
Aziz Ekşi
Keyword(s):  
Red Grape ◽  
Grape Juices

scholarly journals Comparison of Flow Injection-MS/MS and LC-MS/MS for the Determination of Ochratoxin A

Toxins ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 547
Author(s):  
Kai Zhang
Keyword(s):  
Ochratoxin A ◽  
Flow Injection ◽  
Internal Standard ◽  
Grape Juice ◽  
Tandem Mass ◽  
Triple Quadrupole ◽  
On Line ◽  
Red Grape Juice ◽  
Red Grape

Two methods for measuring ochratoxin A in corn, oat, and grape juice were developed and compared. Flow injection (FI) and on-line liquid chromatography (LC) performances were evaluated separately, with both methods using a triple quadrupole tandem mass spectrometer (MS/MS) for quantitation. Samples were fortified with 13C uniformly labeled ochratoxin A as the internal standard (13C-IS) and prepared by dilution and filtration, followed by FI- and LC-MS/MS analysis. For the LC-MS/MS method, which had a 10 min run time/sample, recoveries of ochratoxin A fortified at 1, 5, 20, and 100 ppb in corn, oat, red grape juice, and white grape juice ranged from 100% to 117% with RSDs < 9%. The analysis time of the FI-MS/MS method was <60 s/sample, however, the method could not detect ochratoxin A at the lowest fortification concentration, 1 ppb, in all tested matrix sources. At 5, 20, and 100 ppb, recoveries by FI-MS/MS ranged from 79 to 117% with RSDs < 15%. The FI-MS/MS method also had ~5× higher solvent and matrix-dependent instrument detection limits (0.12–0.35 ppb) compared to the LC-MS/MS method (0.02–0.06 ppb). In the analysis of incurred corn and oat samples, both methods generated comparable results within ±20% of reference values, however, the FI-MS/MS method failed to determine ochratoxin A in two incurred wheat flour samples due to co-eluted interferences due to the lack of chromatographic separation.

scholarly journals Determination of rheological behaviour of wine lees

2015 ◽  
Vol 29 (3) ◽  
pp. 307-311 ◽  
Author(s):  
Jaromír Lachman ◽  
Kazimierz Rutkowski ◽  
Petr Trávníček ◽  
Tomáš Vítěz ◽  
Patrik Burg ◽  
...  
Keyword(s):  
Dynamic Viscosity ◽  
Rheological Behaviour ◽  
Volatile Acid ◽  
Second Phase ◽  
Temperature Hysteresis ◽  
Chemical Background ◽  
Rate Test ◽  
Red Grape ◽  
Increasing Temperature

Abstract This study deals with the rheological properties of wine lees. Samples of wine lees of the Saint Laurent variety were used in this experiment. The investigated wine lees arose in the process of production red grape wine in 2013 (Czech Republic). At first, the chemical background was determined. The chemical background includes the following chemical parameters: total acidity, pH, alcohol content, reduced sugars, free SO2, total SO2, and volatile acid. In the second phase of the study, physical properties were determined. Specifically, a sample of wine lees was subjected to rheological tests. These tests consisted in determination of dependence of dynamic viscosity on the temperature, hysteresis loop tests, dependence of dynamic viscosity on the time and step-down in the shear rate test. The experiment demonstrated that the dynamic viscosity increased with increased temperature – this phenomenon is caused by thermolabile proteins – and the wine lees has rheopectic behaviour; the degree of rheopexy was found to rise with the increasing temperature.

scholarly journals Integrated analyses of phenolic compounds and minerals of Brazilian organic and conventional grape juices and wines: Validation of a method for determination of Cu, Fe and Mn

2018 ◽  
Vol 269 ◽  
pp. 157-165 ◽  
Author(s):  
Maria da Conceição Prudêncio Dutra ◽  
Lucicleide Leonice Rodrigues ◽  
Débora de Oliveira ◽  
Giuliano Elias Pereira ◽  
Marcos dos Santos Lima
Keyword(s):  
Phenolic Compounds ◽  
Fe And Mn ◽  
Grape Juices

Determination of Color in White Wine and White Grape Juice Using the White Wine Colorimeter

1977 ◽  
Vol 60 (3) ◽  
pp. 739-740
Author(s):  
Herb L Wildenradt ◽  
Paul A Stafford
Keyword(s):  
Grape Juice ◽  
White Wine ◽  
Color Measurement ◽  
White Wines ◽  
Reproducible Method ◽  
Grape Juices

Abstract Further experience with the white wine colorimeter has demonstrated that this instrument provides a simple and reproducible method of color measurement for both finished and unfinished white wines and white grape juices. In view of the proven accuracy and utility of the white wine colorimeter, the method specifying this instrument, 11.B01–11.B02, has been adopted as official final action.

The Determination of Red Grape Quality Parameters Using the LOCAL Algorithm

2006 ◽  
Vol 14 (2) ◽  
pp. 71-79 ◽  
Author(s):  
R.G. Dambergs ◽  
D. Cozzolino ◽  
W.U. Cynkar ◽  
L. Janik ◽  
M. Gishen
Keyword(s):  
Quality Parameters ◽  
Local Algorithm ◽  
Grape Quality ◽  
Red Grape
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