The meaning of bereshit as "in the beginning" is grammatically
unwarranted. It is also semantically odd: the priests would hardly
welcome the earliest - the worst - fruits.
Rather, bereshit means "principally, most importantly." In the case of
fruits, it is choice fruits rather than firstfruits.
Vadim Cherny
[b-hebrew] THWM - Proper name or not?,
Vadim Cherny, 09/24/2009