Table 1 Real and coded levels of variables used in CCD experiments and the responses glucose concentrations obtained with 6- and 48-h enzymatic hydrolysis ± SD

− 1.0 (40.2)

− 1.0 (34.9)

13.48 ± 0.16^b

13.30 ± 0.66^b

14.06 ± 0.82^ab

15.11 ± 0.11^a

14.75 ± 0.26^a

11.95 ± 0.32^c

− 1.4 (30.0)

+ 1.0 (205.1)

21.75 ± 1.08^a

21.04 ± 0.76^ab

20.12 ± 0.05^ab

20.27 ± 0.25^ab

19.37 ± 0.70^ab

18.79 ± 0.86^b

+ 1.0 (89.8)

− 1.0 (34.9)

7.91 ± 0.15^ab

7.37 ± 0.28^b

8.30 ± 0.35^ab

8.24 ± 0.32^a

8.03 ± 0.50^ab

7.43 ± 0.22^b

+ 1.0 (89.8)

+ 1.0 (205.1)

10.15 ± 0.37^a

9.94 ± 0.28^a

10.15 ± 0.31^a

10.53 ± 0.44^a

10.18 ± 0.43^a

9.77 ± 0.18^a

− 1.4 (30.0)

0 (120.0)

21.08 ± 0.46^ab

21.84 ± 0.87^a

21.35 ± 0.62^ab

20.05 ± 0.71^b

21.05 ± 0.92^ab

19.86 ± 0.41^b

+ 1.4 (100.0)

0 (120.0)

6.26 ± 0.13^c

6.19 ± 0.18^c

7.20 ± 0.30^a

6.95 ± 0.36^ab

6.49 ± 0.10^bc

6.95 ± 0.06^ab

0 (65.0)

− 1.4 (0.0)

7.44 ± 0.30^bc

7.42 ± 0.15^bc

8.28 ± 0.49^a

8.00 ± 0.33^ab

7.61 ± 0.19^abc

7.12 ± 0.29^c

0 (65.0)

+ 1.4 (240.0)

16.89 ± 0.57^ab

16.96 ± 1.04^ab

15.44 ± 0.56^b

17.93 ± 1.06^a

17.94 ± 0.58^a

16.47 ± 0.34^ab

0 (65.0)

0 (120.0)

16.22 ± 0.67^a

15.56 ± 0.35^a

15.11 ± 0.73^a

16.18 ± 0.90^a

15.36 ± 0.87^a

16.12 ± 0.79^a

0 (65.0)

0 (120.0)

13.02 ± 0.37^bc

13.15 ± 0.23^bc

13.58 ± 0.23^ab

14.62 ± 0.65^a

12.28 ± 0.09 ^cd

12.05 ± 0.58^d

0 (65.0)

0 (120.0)

10.95 ± 0.51^b

12.65 ± 0.12^a

10.56 ± 0.47^b

13.56 ± 0.68^a

12.62 ± 0.29^a

10.76 ± 0.58^b

− 1.0 (40.2)

− 1.0 (34.9)

23.07 ± 0.46^b

20.42 ± 0.77^bc

22.07 ± 0.38^bc

26.85 ± 1.56^a

26.62 ± 2.80^a

19.68 ± 1.24^c

− 1.4 (30.0)

+ 1.0 (205.1)

31.33 ± 0.86^c

35.68 ± 2.58^a

32.31 ± 0.55^b

34.74 ± 0.75^a

31.75 ± 0.04^c

28.46 ± 1.45^d

+ 1.0 (89.8)

− 1.0 (34.9)

8.92 ± 0.66^b

9.09 ± 0.66^b

10.65 ± 0.40^a

9.53 ± 1.01^ab

10.03 ± 0.75^ab

9.29 ± 0.28^ab

+ 1.0 (89.8)

+ 1.0 (205.1)

13.69 ± 1.38^a

13.07 ± 0.39^a

14.72 ± 1.19^a

13.95 ± 0.56^a

14.66 ± 1.00^a

13.37 ± 0.88^a

− 1.4 (30.0)

0 (120.0)

31.77 ± 0.65^bc

38.00 ± 0.96^a

33.93 ± 1.53^b

33.49 ± 1.59^b

29.62 ± 0.76^c

31.74 ± 0.88^bc

+ 1.4 (100.0)

0 (120.0)

8.49 ± 0.28^a

8.51 ± 0.17^a

8.93 ± 0.24^a

9.31 ± 0.44^a

8.63 ± 0.49^a

8.44 ± 1.13^a

0 (65.0)

− 1.4 (0.0)

8.74 ± 0.29^c

8.74 ± 0.06^c

10.28 ± 0.85^a

9.94 ± 0.31^ab

9.17 ± 0.10^bc

8.76 ± 0.71^c

0 (65.0)

+ 1.4 (240.0)

26.27 ± 0.23^ab

29.33 ± 3.55^a

22.39 ± 0.44^b

29.01 ± 2.81^a

28.71 ± 3.22^a

24.97 ± 1.00^ab

0 (65.0)

0 (120.0)

25.75 ± 2.74^a

22.29 ± 2.23^a

22.01 ± 2.71^a

22.67 ± 1.63^a

22.45 ± 3.09^a

22.65 ± 4.00^a

0 (65.0)

0 (120.0)

25.17 ± 0.28^a

23.02 ± 1.78^ab

24.23 ± 0.76^a

24.89 ± 2.11^a

22.66 ± 1.30^ab

20.14 ± 0.44^b

0 (65.0)

0 (120.0)

16.89 ± 1.53^c

25.51 ± 0.63^a

16.02 ± 0.87^c

22.97 ± 0.88^b

23.26 ± 1.39^ab

15.57 ± 1.13^c