TY - JOUR T1 - Heat Haze Characteristics of Fractionated Wine Proteins JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 123 LP - 127 DO - 10.5344/ajev.1991.42.2.123 VL - 42 IS - 2 AU - E. J. Waters AU - W. Wallace AU - P. J. Williams Y1 - 1991/01/01 UR - http://www.ajevonline.org/content/42/2/123.abstract N2 - 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. ER -