Albert Barnes Commentary Leviticus 2:11-12

"No meal-offering, which ye shall offer unto Jehovah, shall be made with leaven; for ye shall burn no leaven, nor any honey, as an offering made by fire unto Jehovah. As an oblation of first -[fruits] ye shall offer them unto Jehovah: but they shall not come up for a sweet savor on the altar." — Leviticus 2:11-12 (ASV)

As for the oblation of the firstfruits - Rather, as an oblation of firstfruits. The words refer to the leaven and honey mentioned in Leviticus 2:11 which might be offered among the firstfruits and tithes (Deuteronomy 26:2, Deuteronomy 26:12; compare 2 Chronicles 31:5). Honey, being used to produce fermentation, and leaven (or, a small piece of fermented dough) were excluded because fermentation was an apt symbol of the working of corruption in the human heart.