Sensory evaluation and flavour analysis of soymilk produced from lipoxygenase-free soya beans after modified processes and pulsed light treatment

Conventional static pulsed light (PL) treatment completely inactivated lipoxygenase (LOX) in whole soya beans to prevent off-flavours produced by LOX. However, the produced soymilk had inadequate values for total solid content. The fully soaked treatment (FST) and shaking treatment (SHT) were best in terms of increasing total solid content of soymilk from 3.7% for control soymilk to 4.6% and 4.3%, respectively; therefore, these treatments were chosen for soymilk sensory evaluation. No significant statistical differences in sensory evaluation scores existed between the control and soymilk produced from FST. The SHT for 130s had higher overall liking (4.8) and flavour (4.6) scores compared with the control (4.1 and 3.9, respectively). Flavour analysis (purge and trap GC-MS) of the soymilk revealed that the ethanol peak area was the biggest difference between the treatments. This study demonstrated soya beans treated with PL have no negative sensory effect in general. Producing lipoxygenase-free soya bean is an important achievement to enhance soyfood products because lipoxygenase catalyses lipid oxidation, which takes place when lipoxygenase is released during soy milling.