I couldn’t find any specifics in the literature, but just based on broccoli & cauliflower experience, I suggest that you blanch florets (approx. 1-1.5“ diameter) for 3 min in boiling water and then freeze. The blanching inactivates (kills) enzymes that would cause off-flavor or color change in the product during temperature fluctuations while frozen (frost-free freezers always cycle the temp to warm coils & defrost) or during thawing.

-Diane Barrett