Multifactorial study of haze formation in model wine systems

A multifactorial design was used to study the role of protein (Pro), polyphenols (PP), sucrose (Suc), pectin (Pec), potassium (K), and pH in the formation of haze in wine. Model wines (32) containing two levels of each factor plus yeast and nutrients were made and allowed to ferment to 0 Brix. Measurements of transmission at 633 nm (%T) following heating showed that PP, Pro, Pro*PP, Pec, and PP*Pec were all significant factors affecting turbidity. Molecular weight and size determinations by size-exclusion chromatography-laser light scattering indicated that molecular weight depended on Suc*Pec, Pro*PP*pH, and Pro*Pec*pH while molecular radius depended on PP*Suc*Pec, Pro, PP*Pec, and Suc*pH. Measurement of protein after filtration showed that Pro, PP, Pro*PP, and Pro*PP*pH were all factors. Laser diffraction studies showed three primary peaks in the range 0.05-800 mum. The smallest size range had Pro*pH as a significant factor, while the largest had Pec and Pro*K as factors. These results indicate that a variety of factors are important to haze formation and that measurement of particle size, distribution, and interactions depends upon the instrument used to measure it.