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Titration and buffer capacity curves of Mozzarella, Cheddar and Cottage cheese-type wheys were studied at concentrations of 6-24% solids. Buffer maxima due to lactate and phosphate occurred at pH 3.2 -4.0 and 5.6 -7.0, respectively, and were dependent on the type and concentration of whey. Titration curves of all whey varieties intersected at pH 3.7. An equation was developed to define whey pH as a function of pH at dipping, concentration and level of HCl or NaOH (r = 0.99, p < 0.01). The pH of Mozzarella and Cheddar cheese-type whey decreased during concentration but the pH of Cottage cheese whey increased. This difference is explained by calcium-phosphate equilibria in whey.

Use of nitrate in the manufacture of certain cheeses is sometimes questioned because of its potential involvement in formation of N-nitrosamines. Unlike cured meats, there was not much information available, until recently, regarding the presence of N-nitrosamines in cheese and other dairy products. This paper briefly reviews the mechanism of formation of such compounds in foods and discusses the necessity of selective and sensitive methods of analysis. Factors which may possibly influence formation of N-nitrosamines in cheese as well as further areas of research are also discussed.

A fast protein liquid chromatography system was used to fractionate the major proteins of sweet and acid wheys. Fifty to 500 microliter of whey were fractionated with a stepwise ionic strength gradient using water (buffer A) and increasing concentrations of .7 M sodium acetate (buffer B). Six well-resolved peaks were obtained: 1) amino acids (tentative identification), 2) low molecular weight peptides (tentative identification), 3) highly enriched alpha-lactalbumin, 4) highly enriched serum albumin 5) electrophoretically pure beta-lactoglobulin B, and electrophoretically pure beta-lactoglobulin A. A poor baseline or unresolved peaks resulted when .02 M bis-tris or .02 M histidine was used for buffer A and .7 M sodium acetate in .02 M bis-tris or histidine was used for buffer B. When sodium chloride was used in place of sodium acetate, beta-lactoglobulins A and B were poorly resolved. The column was cleaned after each run by injecting 2 ml of the following reagents: glacial acetic acid, 2 N sodium chloride, 2 N sodium hydroxide, 2 N sodium chloride, 2% detergent, and 100% acetonitrile. Time required to run each sample including column cleanup was 40 min.

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