Chemical properties of whole wheat breads. Whole wheat breads contain a high amount of phytic acid, which tends to lower the absorption of nutrient minerals. The Journal of Agricultural and Food Chemistry (Jan. 2005) published the results of a study to determine whether sourdough can increase the solubility of whole wheat bread. Four types LO4 of bread were prepared from whole meal flour: (1) yeast added, (2) sourdough added, (3) no yeast or sourdough added (control), and (4) lactic acid added. Data were collected on the soluble magnesium level (percent of total magnesium) during fermentation for samples of each type of bread and were analyzed with the use of a one-way ANOVA. The four mean soluble magnesium means were compared in pairwise fashion with Bonferroni’s method.

The results are summarized as follows:

Mean: 7% 12.5% 22% 27.5%

Type of Bread: Control Yeast Lactate Sourdough

a. How many pairwise comparisons are made in the Bonferroni analysis?

b. Which treatment(s) yielded the significantly highest mean soluble magnesium level? The lowest?

c. The experimentwise error rate for the analysis was .05.

Interpret this value.