Figures (5)  Tables (3)

    • Figure 1. 

      Response surface graphs displaying the effect of (a) soaking time and temperature on yield, (b) soaking temperature and steaming time on yield, (c) soaking time and steaming time on b-value, (d) soaking time and steaming time on cooking time, (e) soaking temperature and steaming time on cooking loss, and (f), (g) steaming time, drying time, and drying temperature on hardness.

    • Figure 2. 

      (a) Raw, (b) cracked raw, (c) parboiled, and (d) bulgur wheat.

    • Figure 3. 

      X-ray diffraction plot of raw and bulgur wheat.

    • Figure 4. 

      (a) FTIR spectra of raw and bulgur wheat. (b) Conformational peak in the Amide I region of raw wheat. (c) Conformational peak in the Amide I region of bulgur wheat. (d) Secondary structure peak contribution of raw and bulgur wheat (in %).

    • Figure 5. 

      Scanning electron microscopy images of (a) raw and (b) bulgur wheat.

    • Run A B C D E YLD b* CT CL HRD
      1 60 3 15 60 13 80.94 21.60 15.46 15.23 21.41
      2 60 2 15 50 13 85.43 19.53 14.29 16.98 11.17
      3 60 3 15 60 13 82.93 21.20 15.31 15.45 21.43
      4 60 3 15 60 13 82.84 21.60 15.13 15.25 23.02
      5 70 3 15 60 12 72.62 23.81 17.21 13.76 30.31
      6 50 3 15 60 14 80.29 19.85 14.55 17.69 14.53
      7 70 3 15 70 13 70.15 24.28 17.35 13.64 32.25
      8 60 3 15 70 12 79.68 21.89 15.53 15.18 21.61
      9 60 2 20 60 13 83.27 21.85 15.35 16.17 18.76
      10 60 2 10 60 13 84.65 19.19 14.00 17.42 15.52
      11 60 4 15 50 13 76.78 21.75 16.14 14.81 24.49
      12 60 3 20 60 12 77.68 22.26 16.18 14.85 23.59
      13 50 4 15 60 13 78.16 19.78 15.21 16.90 16.72
      14 60 4 20 60 13 74.73 23.59 17.35 14.30 28.52
      15 60 3 10 70 13 80.38 20.32 15.05 15.94 20.15
      16 60 3 10 60 14 80.57 20.21 14.56 16.02 19.60
      17 50 3 15 70 13 79.42 20.32 15.13 17.57 14.86
      18 70 3 20 60 13 66.00 25.10 18.00 12.90 36.53
      19 60 3 15 50 12 79.67 20.87 15.26 15.50 20.33
      20 60 3 20 50 13 78.53 22.04 16.14 14.89 22.95
      21 70 3 15 60 14 71.49 24.01 17.30 13.71 31.16
      22 60 3 10 60 12 83.57 19.91 14.48 16.24 19.34
      23 60 3 20 70 13 79.37 22.83 16.41 14.79 24.54
      24 60 3 15 60 13 80.94 21.60 15.46 15.23 23.02
      25 70 2 15 60 13 78.01 22.49 16.52 14.95 24.27
      26 70 3 15 50 13 71.11 23.17 17.18 13.84 29.21
      27 60 3 15 60 13 82.93 22.12 15.41 15.30 21.43
      28 60 3 20 60 14 80.49 22.53 16.27 14.82 23.92
      29 50 3 15 50 13 78.25 18.95 14.29 18.01 14.59
      30 60 4 10 60 13 78.84 20.62 16.05 14.87 23.04
      31 60 3 15 70 14 79.92 21.91 16.05 15.04 22.18
      32 60 4 15 60 14 77.79 22.98 16.24 14.71 25.46
      33 60 3 15 50 14 80.41 20.96 15.31 15.48 20.63
      34 60 4 15 70 13 76.88 23.22 16.40 14.62 26.30
      35 60 2 15 60 14 87.46 20.02 14.59 16.74 17.03
      36 50 3 15 60 12 79.49 19.44 14.33 17.83 14.68
      37 60 3 15 60 13 81.95 21.60 15.46 15.23 21.41
      38 60 2 15 60 12 85.31 19.89 14.43 16.83 16.49
      39 70 4 15 60 13 64.70 24.86 17.45 13.17 36.10
      40 50 3 20 60 13 79.53 20.57 15.25 17.40 15.18
      41 50 2 15 60 13 80.87 19.16 13.56 18.84 14.25
      42 60 3 10 50 13 82.26 19.56 14.58 16.41 18.88
      43 60 2 15 70 13 84.13 20.69 15.00 16.59 17.37
      44 50 3 10 60 13 77.93 18.78 14.06 18.32 13.97
      45 60 4 15 60 12 76.89 21.86 16.20 14.75 25.39
      46 70 3 10 60 13 75.50 21.83 17.09 14.52 27.07
      A, soaking temperature (°C); B, soaking time (h); C, steaming time (min); D, drying temperature (°C); E, drying time (h); YLD, yield (%); b*, b-value (yellowness/blueness); CT, cooking time (min); CL, cooking loss (%); HRD, hardness (N).

      Table 1. 

      Experimental runs and corresponding responses.

    • Source of variation DF SS MS F-value Significant
      model terms
      Y1 Model 20 987.01 49.350 87.84***
      Linear 5 555.24 111.048 197.65*** A***, B***, C***
      Square 5 357.72 71.543 127.34*** A2 ***, C2 ***, D2 ***
      Interactions 10 74.05 7.405 13.18*** AB***, AC***, CE**
      Lack-of-fit 20 9.41 0.470 0.51 ns
      Pure error 5 4.64 0.928
      Total 45 1001.05
      Goodness-of-fit R2 = 0.986,
      Adj. R2 = 0.974
      Y2 Model 20 116.769 5.8384 73.41***
      Linear 5 113.453 22.6906 285.29*** A***, B***, C***, D***, E*
      Square 5 1.680 0.3360 4.22** A2*, B2*, C2*
      Interactions 10 1.636 0.1636 2.06 ns AB**, AC*
      Lack-of-fit 20 1.560 0.0780 0.91 ns
      Pure error 5 0.428 0.0856
      Total 45 118.757
      Goodness-of-fit R2 = 0.983,
      Adj. R2 = 0.969
      Y3 Model 20 51.9195 2.5960 59.93***
      Linear 5 49.1806 9.8361 227.08*** A***, B***, C***, D***
      Square 5 2.3532 0.4706 10.87*** A2***, C2*
      Interactions 10 0.3858 0.0386 0.89 ns
      Lack-of-fit 20 0.9958 0.0498 2.86 ns
      Pure error 5 0.0871 0.0174
      Total 45 53.0024
      Goodness-of-fit R2 = 0.979,
      Adj. R2 = 0.963
      Y4 Model 20 89.6167 4.4808 280.52***
      Linear 5 87.2936 17.4587 1092.9*** A***, B***, C***, D***
      Square 5 2.0048 0.4010 25.10*** A2***, B2***, C2*
      Interactions 10 0.3184 0.0318 1.99 ns AC*, BC*
      Lack-of-fit 20 0.3616 0.0181 2.40 ns
      Pure error 5 0.0377 0.0075
      Total 45 90.0161
      Goodness-of-fit R2 = 0.995,
      Adj. R2 = 0.992
      Y5 Model 20 1525.73 76.29 79.61***
      Linear 5 1443.87 288.77 301.37*** A***, B***, C***, D***
      Square 5 34.61 6.92 7.22*** A2**, B2*, D2*
      Interactions 10 47.26 4.73 4.93*** AB***, AC***, BD*
      Lack-of-fit 20 20.54 1.03 1.50 ns
      Pure error 5 3.41 0.68
      Total 45 1549.69
      Goodness-of-fit R2 = 0.984,
      Adj. R2 = 0.972
      Y1, yield; Y2, b-value; Y3, cooking time; Y4, cooking loss; Y5, hardness; DF, degrees of freedom; SS, sum of squares; MS, mean square; Adj., adjusted. * Significant at p < 0.05; **significant at p < 0.01; *** significant at p < 0.001; ns = not significant. A, soaking temperature (°C); B, soaking time (h); C, steaming time (min); D, drying temperature (°C); E, drying time (h).

      Table 2. 

      ANOVA for response variables.

    • Nutritional parameter Raw wheat Bulgur wheat p-value
      Proximate analysis (%)
      Moisture 10.25 ± 0.06 10.05 ± 0.03 0.150
      Carbohydrate 72.69 ± 0.17 74.46 ± 0.72 0.670
      Protein 13.54 ± 0.21 12.96 ± 0.42 0.253
      Fat 1.78 ± 0.07 0.97 ± 0.21 0.025
      Ash 1.74 ± 0.06 1.56 ± 0.08 0.025
      Water-soluble vitamins (mg/100 g)
      Thiamine 0.16 ± 0.03 0.07 ± 0.01 0.037
      Riboflavin 1.80 ± 0.06 1.61 ± 0.04 0.079
      Niacin 17.67 ± 0.03 2.08 ± 0.02 0.000
      Pyridoxine 0.13 ± 0.01 0.05 ± 0.02 0.002
      Pantothenic acid 0.67 ± 0.03 0.17 ± 0.01 0.001
      Minerals (mg/100 g)
      Calcium 68.58 ± 0.79 62.10 ± 1.56 0.031
      Magnesium 181.71 ± 3.20 171.69 ± 3.80 0.129
      Potassium 718.98 ± 19.66 644.61 ± 15.38 0.001
      Phosphorus 508.96 ± 3.19 499.91 ± 1.60 0.082
      Iron 5.65 ± 0.38 5.15 ± 0.16 0.247
      Sodium 8.15 ± 1.04 2.30 ± 0.96 0.017
      Manganese 4.55 ± 0.13 3.89 ± 0.21 0.006
      Zinc 5.78 ± 0.13 4.63 ± 0.11 0.012
      *p < 0.05 indicates a significant difference between samples.

      Table 3. 

      Nutritional composition of raw and bulgur wheat.