A rejected root in The Etymologies of the 1930s glossed “dig” (Ety/DAG), it may have been a transient replacement for √SAP.
Middle Primitive Elvish
sab
root. juice
dag
root. dig
yābā̆-sūka
noun. fruit drink, cider
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
This root was one of a surprisingly large number of roots Tolkien used for “juice”, appearing as ᴹ√SAB in The Etymologies of the 1930s with derivatives ᴹQ. sáva/N. saw “juice” (Ety/SAB). It might be a variant of (hypothetical) early root ✱ᴱ√WASA needed to explain the forms G. gwâs and ᴱQ. vasa “juice” in the Gnomish Lexicon of the 1910s (GL/44). The primitive form ᴹ✶sāba also appeared in a rough 1940 note with the word N. iofog “fruit drink”, though Tolkien ultimately decided the second element was derived from ᴹ√SUK “drink” (TMME/53).
Neo-Eldarin: For purposes of Neo-Eldarin, I would assume this root refers mainly fruit juice and pulp, as opposed to syrup and tree sap which would be derived from ᴹ√PIS.