This is the 3946th most frequent Russian word.
е
"Е" is the 6th letter of the Russian alphabet and represents the [je] or [e] sound.
The word 'е' here is used in the context of emphasizing 'new books' entirely, as an adverb.
Он любит читать и е совершенно новые книги.
He loves to read and reads completely new books.
The word 'е' is utilized to mean 'exactly these' or 'precisely such,' specifying the referred dumplings.
Это е пельмени, попробуй.
These are dumplings, try them.
The word 'е' acts to emphasize that there is only one way in this context, preceded by a strong determinative accent.