Orion star a111 ph

The β stream powder was dispersed in deionized water (5% wt/wt) and allowed to hydrate for 4 h under constant agitation (450 rpm). The pH of the dispersion was 4.7, and 2 M sodium hydroxide solution was used to adjust the pH to a specific value (pH monitored using Thermo Fisher Scientific Orion Star A111 pH meter). After hydration, powdered zinc acetate or calcium acetate was added at the designed molar concentration (0, 25, 50, 75, 100, 150, and 200 mM) . An exception was made for studying the effect of pH on the efficiency of lipid recovery, wherein the pH was adjusted after zinc acetate or calcium acetate addition, because these salts can lower the pH of the β stream dispersion (Figure 1). The samples were then placed in a hot water bath (Thermo Fisher Scientific, model 3582) at 30 or 60°C for 30 min. After this heat treatment, the samples were centrifuged (IEC Centra CL-2, Thermo Fisher Scientific) at 1,800 × g for 5 min at ambient temperature. The samples were then allowed to cool overnight in the refrigerator (2 to 4°C), and the supernatant was then decanted and the lower pellet collected for total lipid extraction and PL quantification. The transmittance of the supernatant was measured at 500 nm using a Beckman Coulter (Brea, CA) DU 720 spectrophotometer as an indicator of effective MFGM precipitation.