First, I'm trying to trace the usage of this word in the Tanach:
וַיִּקַּח מֹשֶׁה אֶת־הֶחָזֶה וַיְנִיפֵהוּ תְנוּפָה לִפְנֵי ה'
מֵאֵיל הַמִּלֻּאִים לְמֹשֶׁה הָיָה לְמָנָה כַּאֲשֶׁר צִוָּה ה' אֶת־מֹשֶׁה׃
Moses took the breast and elevated it as an elevation offering before the LORD; it was Moses’ portion of the ram of ordination—as the LORD had commanded Moses. (Vaikra 8.29)
Onkelos translates Mana as "לְמֹשֶׁה הֲוָה לָחֳלָק", i.g. "portion".
Also Shmuel A 1, 4:
וַיְהִי הַיּוֹם וַיִּזְבַּח אֶלְקָנָה וְנָתַן לִפְנִנָּה אִשְׁתּוֹ וּלְכָל־בָּנֶיהָ וּבְנוֹתֶיהָ מָנוֹת׃
וּלְחַנָּה יִתֵּן מָנָה אַחַת אַפָּיִם כִּי אֶת־חַנָּה אָהֵב וה' סָגַר רַחְמָהּ׃
One such day, Elkanah offered a sacrifice. He used to give portions to his wife Peninnah and to all her sons and daughters;
but to Hannah he would give one portion only—though Hannah was his favorite—for the LORD had closed her womb.
The common motive in those verses and the [possible] meaning of the word Manah is that:
It is a part of a whole, not a stand-alone piece.
It was a part of the sacrifice.
We know that the Manos of Purim are intended for the festive meal so I need to find the Halachic implementation of that motive in Mishloach Manos.
Based on the idea that the person's table is compared metaphorically to the Mizbeah (זה השלחן אשר לפני ה', or שלחנו של אדם מכפר etc) and the meal one prepares and eats on the table is compared to his sacrifice, I would conclude that the proper way of Mishloach Manos is:
To prepare (especially cook) food for his own meal
To give a portion of that meal to others.
In other words, according to this explanation, sending sweets and fresh fruits and tea and coffee etc. that are not a part of his cooked food would not constitute a "Manah".
That would explain the behavior of some Haredi people that have a tradition of cooking a meal or baking a cake and then sending a portion of it to others. (I personally always disgusted such food :(