The gathering of a quorum of members of the committee in an email converstation "for the purpose of discussing or acting upon a matter or matters over which the public body has supervision, control, jurisdiction, or advisory power." is a meeting, according to the terms of the terms of the linked regulation. And so any such "meeting" must be made public. This would mean publishing the emails, for example on the website.
Note, however, "Circulation of draft documents which, are intended only to formalize decisions previously made in a meeting" is explictly excluded from this definition of a meeting.
So, for example, in a regular meeting, you may discuss a matter such as "options for the construction of a new bicycle shed". Having talked about it the meeting publicly decides to build it in brick, and asks you to form a detailed design specification. You create this and circulate it in private. At the next meeting, the detailed document is introduced, approved and finalized, and appended to the public minutes.
You can write memos to confirm and add details to a matter previously discussed in open meeting. If you are circulating information then you are not meeting "for the purpose of discussing and acting upon matters over which [you] have control". That is not a problem. The problem comes if you use email as a way to avoid scrutiny. For example by canvassing opinions or collecting promises of votes at the public meeting. You should not use private memos as a way of avoiding public scrutiny.