Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Group A: liquid nitrogen freezing-grinding directly; Group B: shade-drying directly; Group C: sun-drying directly; Group D: heating at 75°C directly.
