This combination is called synbiotics. Adding some of the protein as partially hydrolyzed whey protein will produce a nutrition bar with a softer texture. Partially hydrolyzed protein is favored by many athletes as it is more quickly digested. This represents the ratio of calories derived from carbohydrates, protein and fat, respectively. In contrast, sweet cream buttermilk is the byproduct of churning cream into butter.
Fluid buttermilk sold on the retail level is generally cultured.
Both varieties are available in dry form for the food industry. Some of the factors that affect protein solubility in a given formulation include pH, ionic strength and solids content. In general, proteins are least soluble at their isoelectric point. As a general rule, proteins that are undenatured are most soluble. Heating whey proteins results in protein denaturation decreasing solubility.