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New apparatus for quality control at ICO.

New apparatus for quality control at ICO

The International Coffee Organization hs recently utilized analytical equipment from NIRSystems, manufacturers of sensory equipment, to examine coffee quality and aid in coffee grading. We talk with A. Beltrao, executive director of the ICO and A. Feria-Morales, head of research and quality unit - Promotion Fund of the ICO in London.

Editor: What is the role of the International Coffee Organization? Beltrao: We act as a clearing house. We facilitate exchanges. At the same time we try to do those jobs which no one else is doing. We could not, for example, find a universally accepted set of standards which could form the basis for a policy of investment in the processing and pricing of coffee. This is why we also have been trying to establish a systematic approach to the elimination of defects in order to improve the quality of coffee.

Editor: So quality of coffee and how to improve it seems to be one of the main concerns here at the International Coffee Organization? Beltrao: Some years ago we started as part of a policy of the Promotion Fund of the Organization to look more closely into matters of quality of coffee. This is not a new subject. It is one which has been preoccupying various sectors of the industry. But the producing countries have been very keen on looking at quality as a sort of integrated package and so we decided to look closely into matters of improvement of quality.

Editor: How do you define quality? Beltrao: We discovered over the years, and through many interviews, that quality could be best defined as absence of defects. Defects, for us, are those things which are perceived universally. In the first place we should identify methods to spot defects and secondly we should not be subjective in matters of quality. We would like to use technology and set standards so that one could be precise and develop methods that are acceptable to all the parties involved. We have also come to recognize that coffee is a beverage in which quality cannot be separated from sensory perception. We looked to different sectors of the industry for cooperation in all areas from picking, drying, processing in the field, transportation, roasting, grinding, brewing and finally serving. All these areas needed to be thoroughly evaluated because they may generate defects at cup level.

Editor: So quality has to be controlled at every single stage? Beltrao: Quality has to be controlled at each step to assure that in the first place you pick the right bean and that you then protect the bean through all processes to the final cup. The point is to recognize coffee as a beverage which appeals to diverse senses and not as a raw material. It is different from wheat which is a commodity you turn into bread in order to eat. In the case of coffee the line to the cup is a much more direct one.

Editor: What is the single most important step in the chain regarding quality? Can one judge the different steps? Beltrao: That is a good question because coffee, like wine, is an old industry and you do not have accepted methods of preparation. It is a matter of tradition. For example, the Swedish trade and the coffee drinking habits of the Swedes follow a certain tradition. Such traditions may have historical connections. Britain and France, for example, have close links with Africa. Markets may also be influenced by a variety of technological developments. So the way people describe quality varies from market to market. We are trying to find common standards and to establish statistically reliable methods to assess defects in the cup and to relate these effects to the point at which they occur in the production/processing chain.

Editor: And you have been successful so far? Beltrao: We believe that we have reached the point where we can say that it is possible to conceive an overall system of quality control. We are now trying to design one integrated system with clear guidelines as to how people should act to comply with it. That is where the NIRSystem's instruments fits so well into what we are doing.

Editor: How can the new achievements be used? Beltrao: In coffee there are no internationally defined minimum standards. It is therefore very important to be able to certify that coffee from country A or region B is the coffee described in the relevant conract. You need to know what you are buying is what you are getting. We believe that equipment will be a valuable tool for helping to correlate coffees to their different regions of origin when we develop an integrated system for quality control.

Editor: Mr. Feria-Morales, tell us about the project you have been working on in collaboration with NIRSystems. Feria-Morales: We have been trying to develop a new tool for the chemical analysis of green coffee. But, before we talk about this project let me give you the background regarding the activities of this laboratory - the Research and Quality Unit as it is known here in the Organization.

This Unit derives its strength from the coffee sensory evaluation activities which are conducted by a professional Sensory Panel using descriptive terminology developed in-house through a two year training program. All panelists are staff members of the Organization and, as I said, they were selected and professionally trained on sensory techniques and their specific application to assess coffee as a beverage. This unit, which is part of the Promotion Fund and totally financed by the coffee producing members of the Organization, works to increase coffee consumption. In order to achieve this objective, one of the tasks conducted by this Coffee Sensory Panel is to identify the diversity of flavors in coffee so that people may recognize and appreciate different coffees. It is usual for people to say "Give me a cup of coffee" and not to ask for a cup of coffee from a specific origin. Nobody has taught them about the diversity of flavors and they generally drink commercial brands of coffee which may be blends of several different origins.

In the Research and Quality Unit we believe that coffee should not be marketed just as a hot beverage but be marketed like wine and known for its many different flavors. People must learn that flavor of a cup of coffee depends on many factors, such as the way it has been processed and how you brew it, how it has been packed, etc. and that the combination of those factors produce different cups of coffee. But, continuing with the description of the activities of this laboratory, we also supplement our coffee sensory work by looking at the state of the art methodologies for the chemical analysis of coffee and their potential correlation with sensory responses. That is how we came in contact with NIRSystems and initiated this project. We have been working together for three years now and so far we have accomplished the calibrations for green coffee. But we believe that more things can be obtained through applications of the Near Infrared equipment.

Editor: What's your traditional way to assess coffee? Feria-Morales: As I already said, we have created a Coffee Sensory Evaluation Panel and it is our most powerful tool for the assessment of coffee quality. The panel is formed by a group of people who come every day to this laboratory to carry out sensory evaluation of brewed coffees. They taste coffees in what we call "blind" tests. They repeat each assessment a minimum of four times. We verify their consistency. If they demonstrate consistency, the data is good. If they do not, the data is useless. Consistency is the key factor. This information is subjective because it has been produced by a human, and human reactions vary from day to day. That is why we wanted to have an instrument, which would enable us to correlate those sensory measurements in a more objective manner.

Editor: Have you been able to procure a tool for that? Feria-Morales: There are different analytical techniques that have produced good correlations to sensory data. However, coffee is a unique product affected by so many variables in the field during growing and in the factories during processing that it has been difficult to establish good correlations between analytical and sensory data which can be applied to all types of coffees. In the case of near infrared spectroscopy we have had limited success with some characteristics but some flavor characteristics are proving more difficult, for example, acidity. Acidity in coffee varies from very little to very sharp and because acidity is mixed with other taste attributes, in particular with bitterness, it is difficult for humans to separate and assess properly its intensity. In such cases it will be difficult to succeed in correlating its sensory measurement with objective analytical techniques.

Editor: How did you select samples of green beans? Feria-Morales: The Organization collects a wide selection of coffee samples from each of the producing member countries. Those samples cover different regions, varieties and different grades and qualities.

Editor: So it is a universal calibration the one you have developed? Feria-Morales: Using the ICO collection of green coffee samples, we have built a catalogue of 450 different green coffee samples. The people in charge of developing the NIR-software used an existing module to select from the 450 samples, a representative group of 80 samples. The next step was to send these 80 green coffee samples for the wet chemical analysis of nine previously selected constituents. These analyses were carried out following standard methodologies and the results were fed back to the computer to develop the calibration curves for further prediction of these nine constituents by the NIR on any new sample of green coffee.

Editor: If someone wants to measure all the constituents today, does he have to conduct wet chemical analysis? Is it expensive to conduct the wet chemical analysis for nine constituents? Feria-Morales: Yes, it is very expensive. The coffee industry may be interested in different coffee variables. Just to give you an example: any manufacturer of soluble coffee would like to know in advance the amount of extractable solids he will get from a coffee he is purchasing so that he can calculate profit margins. You may have people interested in the caffeine content or in the sucrose content. Interests vary depending on the sector of the coffee industry involved. From our point of view, we are trying to see if the instrument can tell from the chemistry of the coffee how it has been processed. This has not been used before because it was too complicated, time consuming and expensive because of the techniques previously involved. For instance, the analysis of lipids takes at least six hours just to extract them using the traditional equipment. So, a batch of samples would involve an enormous amount of laboratory work and time.

Editor: So would you call this a revolutionary technique? Feria-Morales: Not revolutionary but, valuable as a new technique to assist the coffee industry because compared to the existing chemical or instrumental methods, it offers a new and rapid option to monitor quality in a routine and less expensive manner.

Editor: What will be the effects of implementing it? Feria-Morales: It should help to define quality and increase the knowledge of roasters, buyers, traders and producers about their own product.

Editor: Is the biggest concern for a roaster to maintain the same quality? Feria-Morales: Not only to main it, but to improve it, and the near infrared technique could be of great help in achieving that. It could be one of the main applications that you will find demand for. But, until now there has been no easy way to test quality. Coffee roasters may purchase their green coffees even directly from growers to guarantee the preparation of a same blend, however coffees from the same origin may vary from crop to crop making essential the tasting of each coffee purchased to assess its quality. That is why the sensory methodology is so important. It will tell you if a cup of coffee has changed from crop to crop for the purpose of blending.

Editor: Is it expensive having a panel for this purpose? Feria-Morales: Yes, that is why if you prove that there is a good correlation between sensory responses and some kind of objective analytical technique you may reduce the cost of monitoring quality. Why? Because it will be a fast and easy way to perform routine methodology. But one of the main factors that you have to be cautious about with this newly developed technique is its reproducibility through sampling. A small sample represents an entire batch of green coffee, sometimes more than 500,000 bags of 60 kilos each. So, you want to be sure that independent of the sample size you will obtain the same result. The reproducibility has to be very good. So far, we have been talking about green coffee and the reproducibility obtained has been acceptable, but the instrument has the potential to analyze other coffee forms.

Editor: Such as? Feria-Morales: Roasted coffee and brewed coffee. You can analyze a sample of roasted coffee in the same way as for green coffee. So, the number of applications may increase.

Editor: Has this project been the most important step to fulfill your task, to improve the quality? Feria-Morales: I would not go that far. I would say that it is a tool which can supplement significantly the methodologies already available. I cannot say it is the solution but I can say for sure that it has a tremendous potential to allow procedures to be established for monitoring the quality of coffee at the different stages from seed to cup. We started with green coffee because, in this form, a parcel coffee as purchased from producers can only be improved by eliminating defective beans through additional sorting. You cannot improve the quality of the beans further than that.

Editor: How can you benefit from the instrument and the calibrations in the field? Feria-Morales: You can monitor several factors with this instrument. For example, you can establish the chemical differences between coffee that is harvested immature and mature or between coffees that have been properly or improperly processed in the field. Based on the NIR composition of coffee treated under the ideal conditions you can establish alternative compositions of coffee treated under different conditions. Comparisons will show how good the field operation has been. A standard for the correct state of maturity may be developed using this technique. If you know that a sample has been harvested picking only red cherries, the NIR analysis could provide you with an indicator of maturity. That would be your standard. You would be able to identify those changes. It is in this area that I see some potential for applications of this technique.

Editor: Can you send the load back if you are not satisfied? Feria-Morales: That is a question of contracts. If the coffee received by the purchaser is not of the quality stipulated in the contract, he could ask for a new shipment of coffee of the specified quality or seek a reduction of price in accordance with the quality of the coffee received. If differences of opinion still exist between buyer and seller recourse to arbitration may be the only way to get an independent and impartial assessment of the quality of the coffee in question. Near Infrared Spectroscopy could be a valuable tool in this situation.

Editor: What can the producer do to improve the quality? Feria-Morales: The producer can implement new practices in the field at different stages along the production line. For example, producers who have three harvests in one season could analyze differences between coffees obtained from each of the harvests. Using cup tasting or more scientific sensory evaluation it would be possible to determine which of the three harvests produced a beverage with the best quality. In some countries harvesting of coffee is done by stripping branches while in others the practice of selecting cherries one by one is more widespread. These harvesting procedures may show up in the NIR analysis. There are many areas in which the technique can be of some use to help the producer improve coffee quality.

Editor: Presently, are they using subjective methods? Feria-Morales: Yes, cup tasting is the ultimate method to assess the cup quality of a coffee. But, soon an objective method such as the NIR could complement present assessments.

Editor: Can the user of the instrument use calibrations based on his own samples? Feria-Morales: Yes. One of the interesting things about the instruments is that although it has been produced with a universal calibration, you may, with training, develop your own calibrations. If you are a roaster, you do not have to rely on the calibrations that are made by the company. The closer you are to your own samples, the more benefit you get from the equipment. You can develop the instrument for your own specific needs with very little on-site assistance from the NIRSystems' staff. You can reduce the sample population to your own specific case needs and that will give an even better precision for quality control on an everyday basis. This is what most industries are looking for not only for coffee but for the whole food industry.

The constituents in the green bean that can be measured by the NIRS System model 4500 or 6500 are: protein, extractable solids, lipids, sucrose, glucose, caffeine, chlorogenic acids, trigonelline, and moisture.
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Title Annotation:International Coffee Organization
Publication:Tea & Coffee Trade Journal
Article Type:interview
Date:Aug 1, 1990
Words:2937
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