No abstract

The objectives of this study were to investigate the generation of beta-lactoglobulin fragment (142-148) (beta-LG f(142-148) during the hydrolysis of whey proteins, and the in vitro stability of this fragment upon incubation with gastrointestinal and serum proteinases and peptidases. An enzyme immunoassay (EIA) protocol was developed for the quantification of beta-LG f(142-148) in whey protein hydrolysates and in human blood serum. The minimum detection limit was 3 ng/mL. The level of the peptide in whey protein hydrolysates was influenced by the degree of hydrolysis (DH). As expected, highest levels of this peptide were found in hydrolysates generated with trypsin. Sequential incubation of hydrolysates at different DH values with pepsin and Corolase PP, to simulate gastrointestinal digestion, generally resulted in the degradation of beta-LG f(142-148) as determined by EIA. Reversed-phase HPLC and angiotensin-I-converting enzyme (ACE) activity assays demonstrated that synthetic beta-LG f(142-148) was rapidly degraded upon incubation with human serum. Furthermore, beta-LG f(142-148) could not be detected by EIA in the sera of 2 human volunteers following its oral ingestion or in sera from these volunteers subsequently spiked with beta-LG f(142-148). These in vitro results indicate that beta-LG f(142-148) is probably not sufficiently stable to gastrointestinal and serum proteinases and peptidases to act as an hypotensive agent in humans following oral ingestion. The in vitro methodology described herein has general application in evaluating the hypotensive potential of food protein-derived ACE inhibitory peptides.

One hundred and twenty years ago, the first obsidian implements were reported from Hopewellian mounds by Squier and Davis (1848). Since that time, a number of regions have been suggested as the source area: Alaska, the Pacific Coast, Yellowstone National Park, New Mexico, and central Mexico. Neutron activation analysis of the elemental composition of Hopewellian obsidian indicates two separate element groups. One of these, the 150 Group, has its source at Obsidian Cliff in Yellowstone. The second, the 90 Group, is also located in Yellowstone, but the exact flow has not yet been discovered.

ICD deactivation and nonreplacement are unavoidable issues that require clarity for meaningful and ethical implementation. This is an ongoing process.