Q. Can one be yotzi mishloach manos if one of the items is a small bottle of grape juice (about six oz.) or is this too small?
A. Poskim maintain that one should send at least a kezais (28g.) of solid food, and a revi’is (86 cc) of liquids to comply with this mitzva (Eishel Avrohom, Aruch Hashulchan 695: 15). Tzitz Eliezer (14: 65) asserts that three egg-fulls of solid food (3 x 57 = 171g.) are required. Others opine that when hard liquor is given, a small 50cc bottle suffices.
Some Poskim argue that it depends on the wealth and position of the giver and the receiver, since the gift should after all, be the promoter of friendship and not insult. (Biur Halocho ibid. quoting Chaye Adam).
Horav Shlomo Miller Shlit’a opinion is that at least one of the shalach manos should be the large shiur. On the others, if they are at least becoming and decorous for the sender and receiver a smaller amount can be send.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a