Effect of Mixing Time on Properties of Whole Wheat Flour-Based Cookie Doughs and Cookies

Abstract

This study investigated if whole wheat flour-based cookie dough's physical properties were affected by mixing time (1 to 10 min). The cookie dough quality was assessed using texture (spreadability and stress relaxation), moisture content, and impedance analysis. The distributed components were better organized in dough mixed for 3 min when compared with the other times. The segmentation analysis of the dough micrographs suggested that higher mixing time resulted in the formation of water agglomeration. The infrared spectrum of the samples was analyzed based on the water populations, amide I region, and starch crystallinity. The analysis of the amide I region (1700-1600 cm^-1) suggested that β-turns and β-sheets were the dominating protein secondary structures in the dough matrix. Conversely, most samples' secondary structures (α-helices and random coil) were negligible or absent. MT3 dough exhibited the lowest impedance in the impedance tests. Test baking of the cookies from doughs mixed at different times was performed. There was no discernible change in appearance due to the change in the mixing time. Surface cracking was noticeable on all cookies, a trait often associated with cookies made with wheat flour that contributed to the impression of an uneven surface. There was not much variation in cookie size attributes. Cookies ranged in moisture content from 11 to 13.5%. MT5 (mixing time of 5 min) cookies demonstrated the strongest hydrogen bonding. Overall, it was observed that the cookies hardened as mixing time rose. The texture attributes of the MT5 cookies were more reproducible than the other cookie samples. In summary, it can be concluded that the whole wheat flour cookies prepared with a creaming time and mixing time of 5 min each resulted in good quality cookies. Therefore, this study evaluated the effect of mixing time on the physical and structural properties of the dough and, eventually, its impact on the baked product.

Keywords: cookie; dough; fracturability; mixing; spreadability; texture; whole wheat flour.

Figure 1

Visual appearance of the dough after mixing.

Figure 2

Moisture content profile of the cookie dough. Error bars represent the standard deviation of three replicates. For each chart, not sharing the same letter(s) are significantly different by Tukey HSD test.

Figure 3

Bright-field micrograph of dough samples (Magnification 10×).

Figure 4

Segmented regions of water in the dough samples (a) MT1, (b) MT3, (c) MT5, (d) MT7.5, and (e) MT10.

Figure 5

Graphs representing (a) FTIR spectrum of dough samples and (b) Absorbance spectrum of water region in the range of 4000–2800 cm⁻¹.

Figure 6

Graphs showing (a) a representative deconvoluted band of the water region and (b) variation of different peaks obtained in the water region concerning different samples. The alphabets above columns of the same color denote statistically significant (p < 0.05) differences.

Figure 7

Graphs showing (a) Amide I region containing different protein secondary structures in different samples, (b) a representative graph of the deconvoluted Amide I region, and (c) variation of different structures obtained in the Amide I region with respect to different samples. The alphabets above columns of the same color denote statistically significant (p < 0.05) differences.

Figure 8

Graphs showing (a) starch region in different samples, (b) a representative graph of deconvoluted starch region, and (c) variation of ratio obtained in the starch region concerning different samples. The alphabets above columns of the same color denote statistically significant (p < 0.05) differences.

Figure 9

Spreadability profile of cookie dough.

Figure 10

Stress relaxation profile of cookie dough.

Figure 11

Impedance spectroscopy profile of WWF dough.

Figure 12

Visual appearance of the cookies.

Figure 13

Surface topographs of cookies.

Figure 14

Parameters of cookie samples: (a) dimensions of the cookies, (b) spread ratio of the cookies, and (c) moisture content (%) of the cookies. Error bars represent the standard deviation of three replicates. For each chart, those not sharing the same letter(s) are significantly different by Tukey HSD test.

Figure 15

FTIR spectra of cookie samples.

Figure 16

Bar plot of (a) hardness and (b) fracturability of WWF cookies prepared with different mixing times. Error bars represent the standard deviation of three replicates. Those not sharing the same letter(s) for each chart are significantly different by Tukey HSD test.