Effect of Atmospheric Pressure Cold Plasma on the Physiological Biochemistry of Stale Wheat and Its Dough Pasting Properties

The stale wheat was treated 0,14,18,22,and 26 min with 30 W atmospheric pressure cold plasma(APCP),respectively. After 14~26 min APCP treatment,the water drop contact angle of a wheat kernel significantly(P<0.05)reduced,and its germination rate and stale index significantly(P<0.05)decreased while its kernel broken percent and water-absorption rate were significantly increased. The contents of soluble protein and sulfuryl group increased with treatment time. Further analyzed the pasting properties of whole wheat flour showed,compared with the sample treated with 0 min,with the increasing in APCP treatment time,dough development time tended to increase while the dough stability time tended to decrease. The maximum consistency torque(C1),a torque at end of mixing(Cs),the minimum torque(C2),and final torque(C5)all tended to decrease,but the pasting peak torque(C3)and the torque(C4)at end of heating tended to unchanged. The amplitude of C1 torque peak significantly reduced. The weakness of protein network(C1-Cs)tended to decrease,the amylase activity(C3/C4)and the extent of starch retrogradation tended to decrease. These changes were related to a slight increase in heating rate(α)and pasting rate(β),with a decreasing tendency in enzymatic rate(γ). Cold plasma treatment significantly decreased damaged starch in the whole wheat flour. The study suggested that the atmospheric pressure cold plasma could modify the strength of protein network and the pasting properties of whole flour in stale wheat possibly by increasing peroxidase and amylase activities in a wheat kernel.