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This is an interim report describing the study carried out between January 1 and February 16, 2004. This was an initial field investigation with the purpose of characterizing the coffee bean fermentation process by following the time profile of important bio-chemicals for fermentation. To our knowledge it is the first field study of this type. .[CLICK]

This presentation has three parts. .[CLICK]

• First will be the description of the project, how it developed, the partnership formed to accomplish the project and the objectives of the project. .[CLICK] • Second will be the description of the field study, including the sites, the tests performed on fermenting coffee beans and the results of the tests. .[CLICK] • Finally we will make some recommendations for future work, including development of field tests and a proposed systematic field study of fermentation parameters and coffee quality. .[CLICK]

This project was carried out in the Matagalpa Department in the middle of the mountainous region of Nicaragua. This is the major coffee producing region of Nicaragua and has thousands of small-holder farms where coffee is cultivated, harvested and processed. These farms are the potential beneficiaries of this study. .[CLICK]

Both Susan and Charles Jackels are interested in chemistry research topics with important service components, especially affecting the poor people in developing countries.[CLICK] Susan is a member of ISJACHEM, a world wide network of chemistry faculty in Jesuit institutions. Through the meetings of this organization she met colleagues at University of Central America, Managua and became aware of the economic crisis affecting small-holder coffee farmers in Nicaragua and some efforts to assist them in overcoming this crisis. Prof. Carlos Vallejos is chemistry professor at UCA Managua and her collaborator in this project. .[CLICK] In early 2002, she applied for sabbatical and research support from Seattle University. .[CLICK] The Mission and Endowment Fund of SU provided support for the preliminary phases of this project.[CLICK]

•[CLICK]In 2003, Susan Jackels came to Nicaragua for a planning trip to investigate possible projects on behalf of the coffee farmers. She was accompanied by Prof. Janet Quillian of Seattle University who is Director of the International Development program of SU and served as translator. During this trip, Susan was introduced to the UCA and to the CRS/NI director, Lara Puglielli. She also met Betsy Wier. In these meetings she found that her ideas for a field study of coffee fermentation with the purpose of insuring coffee quality and consistency were of great interest for CRS/NI and UCA. Both organizations were in support of a proposed project. .[CLICK] •She returned to Seattle committed to raise funds, learn Spanish and initiate preliminary research for a field study of fermentation. .[CLICK] •Both she and her husband, Charles Jackels, a Professor of Chemistry at the University of Washington, Bothell, applied for sabbatical leaves to come to Nicaragua to carry out the projec .[CLICK]. •The field study was conducted during January and February 2004 .[CLICK]

There are four main objectives to this project:[CLICK]

Study the coffee fermentation process

Time-profiles of temperature and bio-chemicals

Variations in profiles under different conditions

Look for indicators of fermentation completion and quality[CLICK]

Find and apply experimental methods that can be used on the farm[CLICK]

Use the results of the fermentation study to design a simple test for over-fermentation[CLICK] Help coffee farmers improve consistency and quality with a fermentation test and training[CLICK]

In this slide we present the reasons for selecting these chemicals for measurement. [CLICK]

Over 175 different microorganisms have been identified in fermenting coffee. [CLICK]

Among them are bacteria[CLICK] that are classified as “good fermentation” agents because they grow under the conditions of fermenting mucilage , which included the presence of oxygen, a pH above 5.0, and temperature about 20 degrees.

[CLICK] Furthermore, they produce products such as water, carbon dioxide, and organic acids such as lactic acid. These products do not damage the beans or adversely affect coffee quality. [CLICK]

Enzymes present in the fruit are less active than bacteria[CLICK] and also are considered to result in good fermentation [CLICK] and produce pectic acids. [CLICK]

Yeasts may also begin to grow in the later stages of fermentation. [CLICK] They are considered to bring about “bad fermentation”. They grow at lower pH (below 5.0) and either with or without oxygen. [CLICK] They produce products that include alcohol and acids that are harmful for the beans and produce off-flavors. [CLICK]

Our tests include fermentation conditions of temperature and pH, the food used by the microorganisms(glucose), and the products of the fermentation, Lactic Acid (good) and Alcohol (bad). [CLICK]

The chemical tests required an aqueous solution. This was prepared by:[CLICK]

1.Collecting a 50 mL sample of fermenting beans. [CLICK]

2.The beans were then mixed thoroughly with 50 mL of water. In this manner, the substances in the coffee bean mucilage were transferred to the water and made available for testing. [CLICK]

3.The tests were performed according to manufacturer’s instructions on the resulting solutions. [CLICK]

Two types of tests were performed: [CLICK]

Quantitative tests for pH, Lactic Acid, Glucose and Alcohol. The quantitative tests used a spectrometer to measure accurate numerical concentrations. [CLICK] And qualitative tests for pH, Glucose and Alcohol. These used color charts to identify a range of concentrations. [CLICK]

The mobil laboratory was transported to each farm.

In some cases the laboratory was situated inside a building, while in others it was outside. [CLICK]

Now, for the results…[CLICK]

All fermentation exhibited the same general pH profile. One data set is shown in this slide.

pH remained in the range 5.5 to 5.8 during most of the fermentation time.

During the period from about two hours before completion of fermentation until about two hours afterwards, the pH would fall from above 5.5 to 4.2 or below. A pH of 4.6 was observed to be a good general indicator of the completion of fermentation. [CLICK]

We studied seven fermentation batches and observed times required for completion ranging from 9.6 to 23.6 hours. See the last column in the table. [CLICK]

Now we see in a graph that overlays the seven pH data sets that each of the batches has a similar pH profile. Note that zero on the time axis [CLICK] is the time of completion and that each batch has a pH of 4.6 at that time. [CLICK]

Here are the lactic acid profiles for all seven batches. Three batches[CLICK] showed sharp increases in lactic acid near the completion time, while the other batches produced much less. [CLICK]

This graph shows the alcohol profile for the seven batches. In some cases[CLICK] significant alcohol was produced prior to completion, while in the other cases most production took place after the time of completion. [CLICK]

Here, in the glucose profiles, we see that in all cases glucose is present and is consumed during fermentation. Although very different, the profiles do not give any indication of time of completion or of fermentation quality. [CLICK]

The temperature observations indicate that with only one exception [CLICK] the temperature of fermentation was in the range 21-23 degrees during the entire fermentation process, despite the air temperatures varying considerably throughout the process and from batch to batch. [CLICK]

In summary, our observations are: [CLICK]

pH appears to track the fermentation process well. [CLICK]

Only for the runs at site D do the Lactic acid concentrations increase rapidly as completion is approached . [CLICK] Ethanol concentrations show the largest increases before completion in runs A-1, B-1, and C-1. [CLICK] Glucose measurements are somewhat problematic and do not change much. [CLICK]

The results of this study indicate that a field test kit [CLICK]can be developed for:

1.Prediction of fermentation completion time based on pH

2.Monitoring quality of fermentation based upon alcohol and lactic acid

3.Detection of excessive microbial activity by temperature. [CLICK]

The results also indicate the usefulness of further field studies during the next coffee picking season for:

1.Training in use of the field test kits.

2.Validation of the field test kit by comparison of its results to those obtained with the mobil laboratory.

3.Systematic investigation of the effect on fermentation of water usage during depulping and correlation of alcohol and lactic acid profiles with roasted coffee quality.[CLICK]

And finally, these results suggest the need for research in the university laboratory to develop an improved color chart for the alcohol test and a suitable color strip test for lactic acid. [CLICK]