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Zur Bestimmung der Bioverfügbarkeit von Aminosäuren aus Proteinen und proteinhaltigen Produkten wird die Fläche unter der postprandialen Plasmakonzentrations-Zeit-Kurve der Aminosäuren nach oraler Zufuhr berechnet. Dies geschieht nach Subtraktion der durch zirkadiane Rhythmen bedingten Leerwerte von den gemessenen Plasmakonzentrationen. Zur Ermittlung der relativen Bioverfügbarkeit von zwei Testpartnern, z.B. einem proteinhaltigen Produkt vor und nach einer bestimmten Behandlung oder zwei technologisch verschiedenen Zubereitungen eines bestimmten Proteins, genügt der Vergleich der beiden bereinigten Resorptionskurven. Hierzu werden die entsprechenden Mittelwertkurven des Probandenkollektivs verwendet, da die individuellen Verlaufskurven insbesondere durch diskontinuierliche Magenentleerung erhebliche Verzerrungen aufweisen. Durch die enzymatische Hydrolyse verschlechtert sich die quantitative Bioverfügbarkeit der Aminosäuren bei einem Lactalbumin um zwölf Prozent. Bei Produkten für die Kranken- bzw. Säuglingsernährung ist die Verfügbarkeit aus fertigen Flüssigprodukten um sieben bis zehn Prozent verbessert gegenüber den gleichartigen Trockenprodukten in Pulverform. Bei ultrahocherhitzten Milcheiweißprodukten wird die Verfügbarkeit gegenüber einfach sterilisierten geringfügig um etwa ein Prozent verbessert. Durch die Präparation getrockneter grüner Erbsen für die Verwendung in Fertiggerichten wird die Verfügbarkeit des Proteins um zwanzig Prozent gesteigert. To evaluate the bioavailability of amino acids from proteins and protein-containing products, the area under the postprandial plasma-concentration-time-curve of the amino acids after oral administration needs to be calculated. Therefore, basic values depending on circadian plasma concentration rhythms have to be subtracted from measured values after loading. To determine the relative bioavailability of two tested samples, e.g., a protein-containing product before and after processing or two technologically different preparations of the same protein, it is sufficient to compare their absorption-curves, both corrected by the basic values. For that purpose the mean value-curves corresponding to the group of subjects are used, because the individual courses show considerable differences, in particular due to discontinuous gastric emptying. Enzymatic hydrolysis of a lactalbumin reduces the quantitative bioavailability of the amino acids by 12%. Concerning products used in nutrition of patients and babies, the availability from ready-to-drink liquid products is about 7–10% better than that out of the same dry products in powdered form. Compared with sterilization, ultrahigh heat treatment of milk protein products improves the availability slightly, by about 1%. Processing of dried green peas destined for use in convenience food increases the protein availability by 20%.

The 175-kDa Plasmodium falciparum erythrocyte binding protein (EBA-175) binds to its receptor, sialic acids on glycophorin A. The binding region within EBA-175 is a cysteine-rich region identified as region II. Antibodies against region II block the binding of native EBA-175 to erythrocytes. We identified a P. falciparum strain, FVO, that could not invade erythrocytes devoid of sialic acids due to prior neuraminidase treatment, and in addition, we used a strain, 3D7, that could invade such sialic acid-depleted erythrocytes. We used these two strains to study the capacity of anti-region II antibodies to inhibit FVO and 3D7 parasite development in vitro. Analysis of growth-inhibitory effects of purified FVO anti-region II immunoglobulin G (IgG) with the FVO and 3D7 strains resulted in similar levels of growth inhibition. FVO and 3D7 strains were inhibited between 28 and 56% compared to control IgG. There appeared to be no intracellular growth retardation or killing of either isolate, suggesting that invasion was indeed inhibited. Incubation of recombinant region II with anti-region II IgG reversed the growth inhibition. These results suggest that antibodies against region II can also interfere with merozoite invasion pathways that do not involve sialic acids. The fact that EBA-175 has such a universal and yet susceptible role in erythrocyte invasion clearly supports its inclusion in a multivalent malaria vaccine.