Heat Haze Characteristics of Fractionated Wine Proteins
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[1] Australian Wine Research Institute
Australian Wine Research Institute
Australia
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[2] University of Adelaide
University of Adelaide
Australia
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- Localización: American Journal of Enology and Viticulture, ISSN 0002-9254, Vol. 42, Nº 2, 1991, págs. 123-127
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
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Resumen
The proteins of a heat-unstable wine were fractionated by a combination of salting out with (NH4)2SO4 and ultrafiltration. The protein composition of the fractions, as observed by electrophoresis, and to a lesser extent by amino acid content, was distinct. The least soluble fraction [A, precipitated with 60% saturation of (NH4)2SO4] was dominated by a protein band of Mr 32 000, the fraction salted out with 65% to 70% saturation of (NH4)2SO4 [B] had a major protein of Mr 24 000, and the most soluble material [C, supernatant at 70% saturation of (NH4)2SO4] comprised proteins of Mr 26 000 and 24 000 [E] together with a carbohydrate-rich fraction [D]. The Coomassie dye-binding assay was unsuitable for protein quantification of the fractions because it underestimated the true values by 50% to 80%. A micro heat test applied to the fractions showed that the carbohydraterich component [D] was the most thermo-stable and apparently extended this stabilizing effect to the protein components [E] in the original isolate [C]. Fractions B and E gave the most haze with heat.
