| Using a filtration method to produce milk-derived whey protein concentrates (MWPC) directly from milk leads to products that are distinct from traditional whey protein concentrates (WPC) in composition, functionality, volatile and sensory profiles, and storage stability due to differing pH, milk fat levels, and heat treatments. These differences result in products that produce higher foam overruns and more stable foams, result in less turbid solutions, undergo less browning during production, have less brown pigmentation developing over storage, have fewer volatile compounds present and increasing in relative concentration during storage, and have fewer negative sensory attributes defining their sensory profiles. Additionally, altering the parameters used during production results in MWPC with compositions and functionalities that differ from each other. Improved WPC ingredients such as MWPC with less variability could lead to more widespread use of WPC as functional ingredients.;The variability of WPC can be exploited, however, in an effort to determine the mechanism of hardening in high protein nutrition bars (HPNB). Although many mechanisms for this hardening have been proposed, none are definitive. In an attempt to elucidate a more definitive mechanism, a two-step process was used in which the effects that various milk proteins have on HPNB were first determined then exploited to probe molecular-level occurrences. In the preliminary study, multiple ingredient functional properties and characteristics related to HPNB hardening, with degree of hydrolysis (DH) appearing to be a key feature in predicting hardening (R2 = -0.86; p = 0.02). Differing DH is indicative of variations in enzyme specificity and hydrolysis conditions, also likely to influence protein characteristics such as surface activity. In the second study, variations based on these characteristics in protein interactions with other proteins, water, and sugars in HPNB were analyzed on a molecular level by considering Maillard browning, water activity, and the types of network bonds formed. Results indicate that differences in HPNB network structure and interactions between proteins, water, and sugar exist based on variations in WPH DH and related protein characteristics in a way that allow for further elucidation of the mechanism of HPNB hardening. |
