Barley malt syrup is a sweetener produced from sprouted barley. Malt syrup is dark brown, thick and sticky; and possesses a strong distinctive flavor that can only be described as "malty". It is about half as sweet as white sugar.
The sugar profile of barley malt syrup will vary with manufacturers but a typical profile is approximately 76.13 percent maltose, 15.81 percent glucose, 6.3 percentsucrose, 2.04 percent fructose and the remainder is lactose. So the total fructose content is likely to be around 5.19%.
Which makes it a no-no.
JohnN