Gatan orius sc 1000 ccd camera

Non-HPJ-treated model milk, 400 MPa-treated skim milk, and 400 MPa-treated model milk were observed using cryogenic transmission electron microscopy (Cryo-TEM), following the methods described by Hettiarachchi et al. (2018) (link) with slight modifications. Samples were diluted 10-fold with distilled water before being added onto a glow-discharged perforated carbon film supported on a 200-mesh copper grid (Ted Pella). The grids were then vitrified in liquid ethane and transferred into a single-tilt cryoholder under liquid nitrogen. The samples were observed with an FEI Tecnai 12 BioTwin electron microscope (120 kV; FEI Company), and ~20 representative images were taken with a Gatan Orius SC 1000 CCD camera (Gatan Inc.).

Selected MC-salt mixtures (with a 5% wt/vol MC) were subjected to cryo-electron microscopy (cryo-EM). Each mixture at ~5°C was diluted 20-fold with 10 mM HEPES buffer (pH 7.0) containing the same concentration of salt as in the mixture. An aliquot (3 μL) obtained from the diluted mixture was deposited onto a glow-discharged holey carbon film supported on a 200-mesh copper grid (Ted Pella, Redding, CA) held in place by a Mark-IV Vitrobot unit (FEI, Hillsboro, OR) for automated cryo-preparation. The grid was then blotted for 2.5 s and vitrified by plunging into liquid ethane. Next the grid was transferred under liquid nitrogen on to a single-tilt cryo-holder (Gatan, Pleasanton, CA) and observed under low dose using a FEI Tecnai 12 BioTwin electron microscope operating at 120 kV. Images were obtained using a Gatan Orius SC 1000 CCD camera (Gatan Inc., Pleasanton, CA).