Egg White Isolate Research Articles

Effects of consuming different protein preloads on appetite, satiety, and subsequent food intake

BackgroundConsistent data from acute, single preload studies demonstrate improvements in perceived appetite and satiety following the consumption of high‐protein preloads compared to normal protein preloads. However, it is currently unclear as to whether protein quality (i.e., protein source) influences these outcomes.ObjectiveTo examine whether the consumption of protein preloads (egg white isolate, whey isolate, micellar casein, and instant egg white) differentially modulate postprandial hunger, fullness, desire to eat, prospective food consumption, eating initiation, and subsequent food intake.MethodsTwelve young adults (age: 22±1 y; BMI: 22.1±0.9 kg/m2) reported to the research facility between 7 – 9 am to complete each 4‐h testing day. A set of questionnaires assessing perceived hunger, fullness, desire to eat, prospective food consumption were completed followed by the consumption of the 130 kcal beverage preloads, varying in protein source. A water preload was also included as a control. The same set of questionnaires along with the assessment of whether they would like to eat again were completed every 30 min throughout the 4‐h postprandial period. After the 4‐h, the participants were given an ad libitum pasta meal to consume until ‘comfortably full.’ResultsThe consumption of the protein preloads improved hunger, fullness, desire to eat, prospective food consumption and delayed the request to eat again vs. the control (water); however, no differences in appetite and satiety outcomes were observed between protein sources. No differences in energy content at the lunch meal were observed between any preloads.ConclusionsWhen comparing high‐quality animal‐based proteins consumed as a beverage preload, relatively no differences in markers of appetite control and satiety were detected, suggesting that protein quality has little impact on these outcomes when consuming 30g of protein.Support or Funding InformationRembrandt Foods

Development of a new product: egg white albumen gels with differentiated magnesium release

Commercial egg white isolates (EWI) or concentrates contain substantial quantities of minerals and they easily form heat-induced gels. An innovative, low mineral EWI was used in the present research to investigate the influence of magnesium ions on the gelation process and on the release of these ions in simulated gastric conditions. Heat-induced gelation of egg white proteins was monitored by using an ultrasound viscometer and an oscillatory rheometer. Samples behaved as weak gels with the storage modulus about 5 times larger than the loss modulus. Both methods revealed two phases of gelation. More elastic behavior of gels with an increased magnesium ion concentration can be explained by a higher number of bonds between protein molecules observed in transmission electron microscopy images. An increased concentration of magnesium ions in gel caused an increased release rate of these ions in simulated gastric conditions, which was probably caused by a higher surface roughness of the gel. Higher roughness of the gel surface enlarges the contact area and enables faster hydrolysis. The egg white isolate gels with a high bioavailability organic form of magnesium could be used as food supplement with a regulated magnesium release rate in the human stomach.

Ca2+-Induced Egg White Isolate Gels with Various Microstructure

Commercially available egg white isolates (EWI) or concentrates can not be used for ions-induced gelation because of high mineral content. In the present research new egg white isolate with reduced minerals content was applied for production of calcium induced gel. At 5.5% critical protein concentration no gel was obtained at the preheating process at 80°C for 30 min. Increased calcium ions concentration formed more elastic gels with higher hardness, adhesiveness and chewiness. There was a linear correlation between (dynamic viscosity) x (density) of the gels and chewiness, hardness and adhesiveness. Higher calcium ions concentration produced more aggregated gels with higher surface roughness. There was a linear correlation between quadratic mean of the surface roughness and maximum roughness height for the gels with different calcium concentration.