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Table 1 Properties to control identity and purity of Masquelier’s grape seed extract. The data were provided by the extract’s manufacturer

From: Masquelier’s grape seed extract: from basic flavonoid research to a well-characterized food supplement with health benefits

Property Standard Method
Organoleptic characteristics
 Aspect Fine powder  
 Color Light brown/pinkish  
 Odor Characteristic woody  
 Taste Astringent, bitter  
Identification   In house
 UV spectrum (approx. 40 mg/L in ethanol 96%) λ max = 280 ± 5 nm  
λ min = 256 ± 5 nm  
 Bate-Smith reaction (approx. 100 mg/L) λ max = 540–550 nm  
Loss on drying ≤10% Ph. Eur. 01/2005: 20817
Sulphated ashes ≤0.5% Ph. Eur. 01/2005: 20414
Solubility conform Ph. Eur. 6.7: 51100
 1% (w/v) in water insoluble < 5%  
 2% (w/v) in methanol Soluble  
 1% (w/v) in isopropanol Soluble  
 0.01% (w/v) in chloroform Insoluble  
 pH (4% (w/v) in water) 2.5–4.5 In house
Residual solvents conform Ph. Eur. 6.7: 20424
 acetone ≤10 ppm  
 chloroform ≤10 ppm  
 ethanol ≤10 ppm  
 ethyl acetate ≤10 ppm  
 n-butanol ≤10 ppm  
Microbiology conform Ph. Eur. 6.7: 50104
 Bacteria <10000 cfu/g  
Enterobacteria <100 cfu/g  
Escherichia coli 0 cfu/g  
Staphylococcus aureus 0 cfu/g  
Salmonella 0 cfu/10 g  
Pseudomonas aeruginosa 0 cfu/g  
 Yeasts and moulds <100 cfu/g  
Mycotoxins Comply with Reg. EC 1881/2006 In house
Pesticide/phytosanitary products a ≤0.05 ppm Ph. Eur. 6.7: 20813
Heavy metals (Fe, Cd, Hg, Pb, As) <1 ppm Ph. Eur. 6.7: 20408
Polychlorinated biphenyls and dioxins Comply with Reg. EC 1881/2006 In house
  1. a The EU has established Maximum Residue Limits (MRL) of pesticides for “certain products of plant origin” (Directive 90/642/EC incl. amendments and corrections). The investigated phytosanitary products include aldrin; 4,4’-dichlorodiphenyldichloroethane; 4,4’- dichlorodiphenyldichloroethylene; 2,4’- dichlorodiphenyltrichloroethane; 4,4’- dichlorodiphenyltrichloroethane; dieldrin; α-endosulfan; β-endosulfan; endrin; α-hexachlorocyclohexane; β-hexachlorocyclohexane; γ-hexachlorocyclohexane; heptachlor; trans-heptachlor epoxide; hexachlorobenzene; methoxychlor