| Processing parameters, including protein starting material, drying technique, acidulant selection, and heating conditions, were investigated to improve and better understand a novel procedure for the modification of whey proteins into an ingredient capable of cold-set thickening, water holding, and weak gelling. The derivatization procedure, consisting of protein hydration, pH adjustment, thermal gelation, drying, and milling, was made more cost effective by applying the process to whey protein concentrates with protein contents of 86, 74, and 64%. Further economic and efficiency improvements to the derivatization process were made by developing a modification to the procedure utilizing spray drying in place of the original freeze drying operation. Rheological characterization revealed the modified derivatization procedure yielded an ingredient with cold-set thickening and gelling abilities similar to the original derivatized powder and was able to achieve textural properties comparable to several polysaccharide thickeners. Investigation of hydrochloric, lactic, citric, and phosphoric acids revealed acidulant selection is an important processing parameter that may modify β-lactoglobulin (β-Lg) gelation and the functional properties of derivatized thickening ingredients. Dramatic acid-specific effects on the rheological and microstructural properties of β-Lg gels and the functionality of derivatized β-Lg powders were in general agreement with classical Hofmeister series behavior. Characterization of acidulant effects and their relative influence on the stability of protein conformation enabled heating conditions to be manipulated to improve attributes of β-Lg gels and instant thickening powders. |
