The cumulative ash curve: a best tool to evaluate complete mill performance

Area of Science:

• Agricultural Science
• Food Science and Technology

Background:

• The traditional slick test for flour stream segregation in roller mills is subjective and relies on human judgment.
• Objective methods are needed to improve the precision of flour stream selection for specific applications.

Purpose of the Study:

• To introduce and validate the cumulative ash curve as a precise tool for flour stream analysis.
• To compare the effectiveness of the cumulative ash curve against the subjective slick test.

Main Methods:

• Wheat was milled using a pilot roller flour mill after standard cleaning and conditioning.
• Flour from different streams (four breaks, five reductions) was collected and analyzed for ash content.
• Cumulative ash curves were plotted using the analytical ash content data.

Main Results:

• Ash content generally increased from the first to the last break passage, with the first break showing 0.71% ash.
• Reduction passages showed increasing ash content (C1-C5), with C3 (0.76%) having slightly higher ash than C4 (0.65%).
• Front reduction passages (C1, C2) yielded high flour quantities with minimal ash, while break passages and rear reduction passages produced less flour with higher ash.

Conclusions:

• The cumulative ash curve provides objective data for flour stream characterization, enhancing precision in milling operations.
• This method aids millers in selecting optimal flour streams based on desired ash content and yield.
• The study highlights the utility of cumulative ash curves in differentiating flour quality from various mill streams.