Plays an essential role in chain termination during de novo fatty acid synthesis (Probable). Possesses thioesterase activity for short chain acyl-ACPs. Substrate preference is 8:0 > 10:0 (PubMed:21831316, PubMed:29491418, PubMed:30409825). H2O + octanoyl-[ACP] = H(+) + holo-[ACP] + octanoate decanoyl-[ACP] + H2O = decanoate + H(+) + holo-[ACP] Belongs to the acyl-ACP thioesterase family.