Definition
An anomer as itself denoted a cyclic saccharide.
Beta anomer is used to refer to a cyclic hemiacetal of an aldose, in which the hydroxyl group at the anomeric position is cis to the CH2OH group.
Explanation
The formation of the hemiacetal is unfavorable, and thus, when the aldehyde and hydroxyl group are placed together, a cyclic hemiacetal is formed. The cyclic form is much more favorable because ring compounds are strain-free.
