Glucosyltransferase catalyzing the beta 1-6 glucosylation of the sugar moiety of crocetin glucosyl esters to produce crocetin gentiobiosyl esters. Weak activity toward curcumin glucosides, but no activity with flavonoid glucosides, coumarin glucosides, 4-nitrophenyl glucoside or crocetin. Involved with UGT75L6 in sequential glycosylation of crocetin to crocin (bis(beta-D-gentiobiosyl) crocetin). beta-D-glucosyl crocetin + UDP-alpha-D-glucose = beta-D-gentiobiosyl crocetin + H(+) + UDP bis(beta-D-glucosyl) crocetin + UDP-alpha-D-glucose = beta-D-gentiobiosyl beta-D-glucosyl crocetin + H(+) + UDP beta-D-gentiobiosyl beta-D-glucosyl crocetin + UDP-alpha-D-glucose = bis(beta-D-gentiobiosyl) crocetin + H(+) + UDP kcat is 0.036 sec(-1) for beta-D-glucosyl crocetin. kcat is 0.071 sec(-1) for bis(beta-D-glucosyl) crocetin. Ubiquitous. Crocin is a yellow pigment that accumulates during fruit development. No other crocetin glucosyl esters detected in neither flowers, leaves, nor stems. No correlation between mRNA expression and pigment accumulation (PubMed:22569263). Belongs to the UDP-glycosyltransferase family.