Learning the Techniques

The International Grains Program’s annual Grain Purchasing course is finishing up this week after two weeks of sessions, networking and field trips. ImageThe Grain Purchasing course started March 31 and wraps up on Friday, April 11, 2014. The course has been held at the International Grains Program Conference Center for the sessions. While in between the two weeks participants traveled to Portland, Ore., to an export facility and then traveled to the Chicago Board of Trade.

During the first week of sessions participants learned from industry professionals on contracting, transportation and logistics, and grain purchasing techniques. The second week is focusing on futures trading techniques, hedging and price risk management.

“Each of the key fundamentals that international grain buyers and traders need to know to conduct their business in a proper way are taught and discussed in this course,” Jay O’Neil, senior economist and course coordinator, says. “It is more than just educating people on how to write a contract and manage risk. ImageWe cover what professionals need to know to protect their company’s best interests and hopefully stay away from trouble.”

A participant from this year’s course, Theiva Muthu from Negeria, says he has learned valuable information at this course that relates directly to his role and would recommend it to his coworkers.

“Sixty percent of my time is invested into commercial sourcing with commodities and a lot of it comes from the U.S. I want to understand more about the sourcing and all the elements that go into it. It helps me understand my job and how to do it better,” Muthu says.

For more information, visit the IGP website at www.grains,ksu.edu/igp.

 

First Year Credentialing Program Graduates

A recent article published on the GEAPS website highlighted the success of the Credential in Grain Operations Management (CGOM) through the GEAPS/Kansas State University Credentialing Program. The first year of the program produced 14 graduates in the industry who were eager to learn and further their knowledge.

The CGOM is accomplished online through the GEAPS/K-State Distance Education Program partnership. The credential is made up of six courses and is the basic credential program. Specialist credentials are also obtainable in Property and Casualty Risk Management, Grain Quality Management, Grain Quality Management, and Grain Handling Equipment Management after the CGOM program is completed.

For the complete article visit GEAPS and for the 2014 course schedule click here.

 

Monitoring Break Roll Wear

How granulation curves may help choose optimal time to change rolls.

In this column, Nathan Watson, a senior majoring in milling science in the Department of Grain Science and Industry at Kansas State University (KSU), Manhattan, offers a review of his study of how granulation curves can be used to monitor break roll wear. Wat­son first presented his findings at the International Association of Operative Millers (IAOM) Wheat State, Texoma, and Central district meeting, March 7, Manhattan, KS. He also made a presentation at the 2013 IAOM Conference and Expo, May 2, in Niagara Falls, ON.  

Watson’s study and presentation were supervised by Chris Miller, instructor, Department of Grain Science and Industry, and Mark Fowler, a regular contributor to Milling Journal and associate director of the International Grains Program (IGP), Department of Grain Sci­ence and Industry, KSU.

Roll wear is a condition that every mill has to manage. Roll wear occurs on rolls when the corrugations wear down as a result of wheat or stock running through the rolls over a period of time.

Maintaining the corrugations on a roll is important for a mill. It helps to keep the mill in balance, maximize farina production in the break system, improve roll performance, and has the potential for energy savings.

On the other hand, roll maintenance is costly for the mill, as well. Changing out a roll pair causes downtime for a mill. There is expense in shipping and re-corrugating the roll pair, labor to replace the roll, and inventory to keep spare rolls and parts on hand for quick changes.

Granulation Curve

Therefore, finding an optimal time between roll changes to minimize maintenance costs and minimize impact to milling performance could be helpful to mill managers.

The granulation curve is a useful tool that has the potential to examine changes over time in the mill. It illustrates the particle size distribution of the milled product for a specific ground stock.

The granulation curve is helpful in showing the mass flow of product throughout the mill.

There are many factors that can change the granulation curve of a milled product, including wheat type, temperature of the wheat and mill, tempering time and moisture, roll wear, mill load, and balance.

In this study, the theory was tested that roll wear should cause noticeable shifts in the granulation curve over time.

Specifically, as a roll wears down, the miller should have to decrease the roll gap, in order to meet the specified break release.

This wear should cause more compression on the stock through the roll. With an increase in compression, the granulation curve shift should show an increase in fine particles and a decrease in coarse farina over time.

Methods Employed

Two local mills that run hard red winter wheat flour agreed to provide samples in this study.

The mills are labeled “Mill A” and “Mill B.” The samples are of ground stock from first break and second break roll stand in each mill on a specific day. A sample of wheat going into the first break roll was included as well.

Sifting and analysis were performed at KSU’s Department of Grain Science and Industry milling laboratories.

First, the wheat was analyzed with the Single Kernel Characterization System (SKCS) for hardness, moisture, weight, and diameter.

Then, each stock for individual passages was sifted. Sifting was performed on a Great Western tabletop sifter box.

The first sifting used sieves with 1041-, 355-, 240- and 132-micron screens. The sample was sifted for two minutes. The weight of each stock on each sieve then was recorded, and the material on top of a 355-micron sieve was saved for a second sifting.

This second sifting analyzed the sizing stock further using 900-, 750-, 630-, 500- and 425-micron sieves. This stock also was sifted for two minutes. The weights then were recorded for each sieve.

One data set that had to be generated was the age of a roll pair, when each stock was collected.

Each stock was collected on a specific day, and the previous roll change was recorded and associated with that sample.

The difference between the stock collection date and the date of the previous roll change gave the age of the roll pair in days after a roll change. This helped to assign consistent ages to compare each curve.

When reviewing the data, it was concluded that Mill A should be our primary focus in this study due to longer average roll life for first break and second break, up to 650 days. This longer time period would be better for our analysis on how changes that occur to the rolls over time.

Granulation Curve Analysis

Once all the data were collected, granulation curves were generated for each break system in each mill.

One observation made was that because of how staggered the roll changes are, and how short of a collection period was utilized, there were several gaps in the roll age that could not be observed. Therefore, selecting data for granulation curve generation was difficult.

However, points were selected and analyzed to space the days evenly over the roll life. Each day includes all data points within +/-5 days of that selected point. The cumulative percent overs were averaged and made into a granulation curve for that period.

In Fig. 1, the granulation curve is generated for Mill A first-break stock. The time periods selected for analysis were days 0, 210, 420, and 600.

One major observation for this stock is some variability in the break release. For example, break release has a major impact in the granulation curve, and this may have impacted the efforts to determine how roll wear could shift the granulation curve.

Fig. 2 shows the granulation curves for second-break stock on Mill A over the roll life.

The break release for this stock is more consistent than the first-break stock. This granulation curve shows much tighter fitting curves. It is difficult to see any changes that determine any effects roll wear has on the curves.

Quantitative Stock Analysis

We moved ahead hoping that the amount of stock produced on specific sieve sizes would indicate better how the individual rolls performed.

For this analysis, the focus was on the second-break stock of Mill A and reducing the variability introduced by the wheat.

The theory is that second-break roll stock may be more consistent by being ground previously, as compared to wheat fed to the first-break roll with variation in hardness and kernel size.

The chart in Fig. 3 shows two trend lines. The top or the decreasing trend line is the percentage of second-break stock that passed through the 1,041-micron sieves and remained over the 500-micron sieve in the same samples.

What is observed is a small, approximately 2%, downward shift in particle size over roll life supporting the theory that roll wear impacts the granulation of ground stock.

Limitations of Study

Wheat variation, sampling procedures, and the changes in mill environment over the period of a year adds variability into this study.

Mill operation factors, including required adjustments to balance the mill flow and product quality, are other elements that introduce some variability to this study.

In the final graph, Fig. 4, the data shows how a change in break release can correlate to a change in flour production.

Over time, the second-break release varies, using a 20-point moving average. This change results in corresponding increases and decreases in flour production for these roll stands.

This shows how important a factor break release can have on the granulation of the stock.

Conclusions

Granulation curves are a way that roll wear can be monitored by a mill.

However, the results from this experiment are not conclusive. There are too many uncontrolled variables in the wheat and milling conditions to see a shift in the granulation from roll wear.

However, a shift in coarse and fine farina production was observed that could indicate roll wear.

Even still, too many variables play a factor in the determination. A controlled laboratory study would be necessary to eliminate some variables and to obtain more conclusive results.

Post-production flour treatments

Steps can be taken after the milling process to

ensure a safe, reliable and consistent product

by Mark Fowler, reprinted with permission by World Grain      

Delivery of a product with the right quality characteristics to the customer is the goal of every business. For the flour milling industry, the process of delivering a safe, reliable and consistent product does not end in the flour mill. There are several post-production treatments that modify and improve the performance of the flour for specific applications.

BLENDING

First of all, as I have mentioned in several of my past articles, blending is the best, most efficient and most important post-production process. Before any other of the post-production processes, the flour should be properly blended to maximize the consistency of the product. Delivery of a homogeneous blend of flour for further processing is vital to delivering flour with repeatable characteristics. Consistency will always be the flour quality characteristic most valued by the customer. The two primary methods of blending flour are continuous blending and batch blending. Continuous blending is the least expensive option. The accuracy of a continuous blending system depends on the accuracy of the bin dischargers and the absence of product chokes in the system. Batch blending is the better option for blending of mixes with several components where more precise measurement of ingredients is required.

ADDITIVES

The most common post-production treatment is the addition of micronutrients and dough improvers. The practice of fortifying bread flour has been a requirement in the United States for several decades. With the lobbying efforts of organizations such as the Flour Fortification Initiative and the Micronutrient Initiative, the health benefits of adding basic vitamins and minerals to flour has been implemented in more than 78 countries across the globe. The combination of vitamins and minerals added to flour varies widely. The U.S. standard includes: niacin, riboflavin, thiamin, folic acid and iron. Requirements in other countries may include vitamin A and zinc.

The precise blend of nutrients which are required is not important. Nutritional needs and deficiencies vary from country to country. The importance of the addition of nutrients is the recognition that flour is an inexpensive method of correcting or preventing a nutrition deficiency to make a healthier population.

The incorporation of enzymes and other flour performance additives is a common practice to modify and improve the functionality of the flour to make a variety of products. From biscuits and crackers to any type of bread production, additives can improve the profitability of mills and bakeries and help to deliver a better product to the consumer. Enzymes are natural substances composed of amino acids. They act as catalysts to modify carbohydrates, fats and proteins. Enzymes can be plant-based such as malted barley or sprouted wheat flour. They also can be fungal or bacterial-based products.

The types of enzymes are as diverse as their function and applications. For example, some enzymes weaken flour gluten, while others strengthen the gluten. They may help to hydrolyze cellulosic material or break down carbohydrates to create sugar to feed yeast or aid in crust color and bread flavor. Other additives such as ascorbic acid can work as an oxidizing or a reducing agent in dough development depending on addition rate and dough forming process. The use of flour additives and improvers increases the consistency of the final product by adjusting flour performance as the wheat quality may change from region to region and year to year.

CHLORINATION

The practice of flour chlorinating is limited to cake flour used for high-ratio cakes. The mixing of chlorine gas with flour lowers the pH due to the formation of hydrochloric acid. Chlorination of cake flour helps to increase cake volume while improving grain and texture. It increases the ability of flour to carry higher levels of sugar and shortening, allowing high-ratio formulas preferred in some markets.

Flour chlorination requires aggressive agitators as the flour particles must be suspended in the gas to absorb it evenly. The agitators must be properly designed to provide adequate Suncue retention time to mix the gas and flour to achieve the target flour pH, typically between 4.4 and 4.8.The danger with chlorine treatment is that chlorine gas is hazardous and harmful if employees are overexposed. Mild exposure may cause respiratory irritation such as coughing or lung congestion as well as irritation to the eyes, nose and throat. Overexposure can cause chronic bronchitis and emphysema.

HYDRATION

Moisture control is one of the most important factors in milling. All mills add water to condition the wheat prior to milling to maximize extraction and optimize the consistency of the flour. However, due to fluctuations in the mill temperature and humidity, the amount of moisture loss during the milling process is difficult to estimate and control. For this reason, it is becoming common for mills to hydrate the flour near the end of the process. A flour hydration system can increase the moisture content of finished flour up to 1.5% to optimize flour moisture to the customer.

Flour hydration can help maximize flour extraction as well. The practice of setting the target conditioned wheat moisture to meet the finished flour moisture required by the customer can mean a compromise on extraction. Depending upon the mill flow, mill environment and type of wheat, the optimal wheat moisture for milling maybe lower than the required moisture to meet customer requirements.

Hydrating the flour after milling allows the mill to determine the optimal wheat moisture to maximize flour quality and extraction, and then adjust the finished flour moisture to meet customer requirements. This allows maximum milling efficiency and optimal finished flour moisture and consistency.

Several companies offer flour hydration systems. The fundamental components of a system are similar and include an intensive mixer, atomized water addition using compressed air and precision control of the water mist added to the flour. Systems are preferably installed after the flour collection conveyor in the mill.

The mixing of flour and water will create a portion of flour balls. For this reason, the scalped product from the mill rebolt sifter should be sent back to a designated mill stream to break up the flour balls and flour recovery. Adequate aspiration of the hydration system and the spouting before and after the mixer is important to prevent microbial growth and flour contamination.

HEAT TREATMENT

Flour heat treatment (FHT) is simply the exposure of flour to a heat source. However, the process of heat treatment is anything but simple. There are two separate but related objectives for the heat treatment of flour. The first objective is, traditionally, the modification of the functional properties of flour for special applications. The more recent and increasingly popular objective is the log reduction of microbial contamination.

Multiple studies have demonstrated significant reduction of microbial contamination in heat-treated flours. One major milling company in the U.S. markets heat-treated flour with a 5-log reduction in the microbial count with no impact to the flour color, taste and protein functionality. The impact to the functional proteins is the greatest concern with the application of a heat treatment process for purpose of food safety. Heating flour above 130 degrees F will result in a change in flour performance.

Applying a FHT process can be useful to deliver and enhance the performance of flour for a wide variety of products. The two primary methods of heat treatment are thermal and hydrothermal. As the name implies, a hydrothermal FHT process is the treatment of flour by heat and moisture in the form of water or steam. Hydrothermal treatment processes have a greater impact on flour functionality. It is used for batter coatings as it enhances the viscosity of flour improving the ability of batters to adhere to food. It also expands the application of wheat flour used as thickeners for soups and sauces.

The thermal FHT process is the treatment of flour by heat only at a specific temperature and time. In most cases, rehydration of the flour is required after thermal treatment to recover moisture content. Thermal treatment is less likely to impact flour functionality as compared to hydrothermal treatment, but can be used to modify functionality if that is the desired objective.

In summary, the production of quality flour is not limited to the milling process. There are several post-production processes that can be used to modify and improve the quality characteristics, create flour characteristics for specific applications and improve product safety. Post treatment processes require additional capital investment and greater quality control. The benefits include improved customer service and mill profitability.

October Courses

The last few weeks of October have been busy with back to back courses. Last week, IGP faculty hosted the AFIA-NGFA-KSU-HACCP Feed course. Participants had the opportunity to focus on HACCP principles and establishing a HACCP program for their feed mill.

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This week, participants joined IGP and AIB faculty for an AIB International-IAOM-IGP Grain Milling HACCP Workshop. This course helped participants understand the Food Safety Modernization Act and the HACCP principles that go with it. IMG_6865

Participants from Ethiopia and Tunisia have been in the building for the last two weeks in the USDA Cochran Animal Feed Production Training. This group has had the opportunity to travel to many of the animal units on the Kansas State University Campus along with classroom lectures from IGP and Grain Science faculty. Ethiopia

AFIA-KSU Advanced Pelleting Course

The International Grains Program, in partnership with the American Feed Industry Association conducted a three day training with a focus on the important concepts needed to run an optimal and efficient pelleting system in a feed manufacturing business. Throughout the course, participants had the opportunity to listen to professionals in the industry, interact with others in the pelleting industry and take part in practical sessions in the KSU O.H. Kruse Feed Mill.

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