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improve the quality of national coffee

RAQUEL DO CARMO SANTOS

DFrom plantation to reaching the cup of the majority of the Brazilian population, coffee goes through a long and complicated process - cultivation, processing, storage and roasting. Therefore, you need to be very careful not to lose the quality of the drink along the way. Brazil, as the largest producer in the world, also has the problem of having the price of its product devalued, compared to other countries. The federal government has even been financing several researches with the aim of obtaining a more competitive product. The truth is that the price of a bag of Brazilian coffee on the international market has decreased compared to the price of a bag of the product distributed by countries in Central America, Mexico, Colombia and Kenya, which achieve good prices in the market because they are considered soft drinks.

Work conducted by researchers from Unicamp and the Agronomic Institute of Campinas (IAC) is joining several other studies to improve the quality of Brazilian coffee. Part of the research "Evaluation of the quality of Coffea canephora and Coffea arabica cultivars selected for the State of São Paulo", financed by Fapesp, was presented as a master's thesis at the Faculty of Food Engineering, by Maria Ivone Martins Jacintho, supervised by Professor Neura Bragagnolo. For the IAC Coffee Center, those responsible for the work are Terezinha de Jesus Garcia Salva (project coordinator) and Oliveiro Guerreiro Filho.

Amidst the various possible stages in which coffee is subjected, Maria Ivone chose to investigate the one that before roasting the beans. "My interest was to evaluate the effect of the preparation method on the chemical composition of the grains to relate it to the quality of the drink." The researcher studied five cultivars of the Arabica species and three of the Robusta species, all developed at the Campinas Agronomic Institute. She explains that the Arabica species (Coffea arabica) is more produced in Brazil and around the world because it is considered to be of better quality and the Robusta species (Coffea canephora) is considered more resistant to pests, but its drink suffers from a certain prejudice on the part of of coffee tasters who consider it to be of inferior quality. The cultivars researched are named: Catuaí Vermelho IAC 81, Mundo Novo, Ouro Verde, Obatã, Tupi of the Arabica species and Conilon, Apoatã and Robusta of the Robusta species.

The innovation of the researcher's work was precisely to analyze several cultivars of the Arabica and Robusta species after subjecting them to the three types of grain preparation that exist - dry, wet and peeled cherry. "This type of study is important as the grains contain chemical compounds that will form the flavor and aroma of the drink", explains Neura.

In the dry process, the grains are placed on the concrete "terrace" and exposed to the sun. They are turned periodically to prevent unwanted fermentation. This is the most adopted type in Brazil. In the wet mode, which produces so-called pulped coffees, the peel and pulp are removed and the mucilage is subjected to a degradation process by microorganisms. This technology is used by Colombians and in several studies it is associated with the quality level of the coffee they produce, due to the increase in desirable acidity and aroma.

The peeled cherry method was recently developed in Brazil. It is a good intermediate alternative between the two modes - dry and wet. In this case, the skin and pulp of the fruit are removed, and the grain with the mucilage is placed on a patio to dry. All coffees used in Maria Ivone's work followed strict control of the preparation stages. "We did everything equally to guarantee the effectiveness of the results", she guarantees.

In a first step, she analyzed the pH, total titratable acidity (related to the acidity level of the drink) and polyphenol oxidase activity (an enzyme present in coffee and it is suspected that the higher its activity, the higher the quality of the product) in samples of raw coffee. Afterwards, the researcher evaluated in roasted coffee, in addition to the pH and titratable acidity, the soluble solids content, an important property for coffee yield, especially in the soluble coffee industry. And finally, it related the sensorial quality - in this item, trained tasters evaluated acidity, bitterness, body, sweetness and overall quality of the drink - with the chemical parameters of the raw and roasted grains.

Conclusions - One of the conclusions of the research was that the majority of cultivars prepared in the pulped and peeled cherry methods presented a better quality drink. "This proves the good results of the method used by the Colombians and confirms the use of the alternative developed in Brazil." Another factor identified as decisive in quality was the type of cultivar. Ouro Verde stood out among the Arabica coffee cultivars studied.

Regarding chemical parameters, the acidity of pulped coffees was higher. "In this case, the result depends especially on the consumer market. The acidity may please some and displease others." The researchers' work did not observe any relationship between the enzyme and the quality of the drink. This could be attributed, explains Neura, to the harvesting method. "In Brazil, cherry beans (of better quality) are often mixed with green beans and defective beans. This can alter the quality of the final product." During the research, cherry-type grains were used.

Maria Ivone's master's thesis is just one part of the Coffee Center project and researchers from the Agronomic Institute will relate other chemical parameters to the quality of the drink. "This type of work is extremely long and complex, but important to restore Brazilian coffee to its natural competitiveness and achieve a better quality product on the international market."