Simultaneous optimization of coffee quality variables during storage

Abstract

A B S T R A C TThe objective of the study was to use methodology of simultaneous optimization of multiple responses applied to an experimental design to determine the best combination of storage period and conditions for preservation of coffee beans. Coffea arabica L. fruits were harvested in the ripe stage of maturation, processed using wet and dry methods, and dried to 11% (wet basis) moisture content. Part of the beans was hulled, while the other part was hulled only after the beans were stored under two different environmental conditions: cooled air at 10 ºC with 50% relative humidity; and at 25 ºC without controlling the relative humidity. Samples were taken at 3, 6, and 12 months intervals in order to evaluate quality. The data were submitted to the simultaneous optimization of responses for each processing and hulling condition separately, in a completely randomized design and 2 x 3 factorial scheme (two storage conditions and three storage periods). In conclusion, the use of the simultaneous optimization of responses is viable to be applied for determining the ideal storage conditions in a refrigerated condition. Otimização simultânea de variáveis da qualidade do café durante armazenamento R E S U M OObjetivou-se utilizar a metodologia de resposta simultânea aplicada a um delineamento experimental para determinar a melhor combinação de tempo e das condições de armazenamento para a conservação de grãos de café. Frutos de Coffea arabica L. foram colhidos no estádio de maturação cereja, processados por via úmida ou por via seca e secados até atingir 11% de teor de água. Parte dos grãos foi beneficiada e parte não foi beneficiada antes de ser armazenada em duas condições de ambiente: em ar refrigerado a 10 ºC e umidade relativa de 50% e em 25 ºC sem controle da umidade relativa do ar. Nos períodos de 3, 6 e 12 meses, foram retiradas amostras para avaliação da qualidade. Os dados foram submetidos à técnica de otimização de resposta simultânea para cada processamento e beneficiamento separadamente, em delineamento inteiramente casualizado e esquema fatorial 2 x 3 (duas condições de armazenamento e três períodos de armazenamento). Conclui-se que a utilização da metodologia de resposta simultânea é viável para ser aplicada para determinação das condições ideais de armazenamento em condição refrigerada.

Quality of Specialty Natural Coffee Stored in Different Packages in Brazil and Abroad

“…Values of maximum, minimum, and mean relative humidity (Figure 1 The mean (21 ºC), mean of maximum (25 ºC) and mean of minimum (17 ºC) temperatures are presented in Figure 1a. The mean storage temperature conditions were considered good for maintaining coffee quality (ABREU, et al, 2017;ABREU et al, 2018), considering that the maximum values did not exceed 30 ºC and the mean values were approximately 20 ºC, with periods of low temperatures of approximately 5 ºC during winter.…”

Farm to Consumer: Factors Affecting the Organoleptic Characteristics of Coffee. II: Postharvest Processing Factors

“…Coffee deterioration and quality loss happen as a result of cellular membrane disintegration/injury and the resulting lixiviation/leaching of solutes/nutrients. Electrical conductance and P lixiviation are the standard tests for checking for cell injuries (Abreu et al., ). Hermetic packaging systems, including GrainPro, also show low values for electrical conductance and P lixiviation (that is, 160 μSiemens/cm/g as compared to 220 μSiemens/cm/g for jute sacks).…”

“…The “off‐notes” also observed during the course of storage are mainly caused by the degradation and oxidation of the nonvolatile fraction of green coffee beans, especially lipids (Kurzrock, Klling‐Speer, & Speer, ; Speer & Kolling‐Speer, ). These off‐notes can be prevented by storing green coffee beans under optimum storage conditions, but flatness in cup quality is also noted even under optimum storage conditions (Abreu et al., ; Selmar et al., ). Some authors also related flatness, slackness, and cup quality of coffee to the viability of coffee seeds (Sivetz & Desrosier, ), which was later approved by many studies (Abreu et al., ; Rendon, Gratao, Salva, Azevedo, & Bragagnolo, ; Selmar et al., ).…”

“…These off‐notes can be prevented by storing green coffee beans under optimum storage conditions, but flatness in cup quality is also noted even under optimum storage conditions (Abreu et al., ; Selmar et al., ). Some authors also related flatness, slackness, and cup quality of coffee to the viability of coffee seeds (Sivetz & Desrosier, ), which was later approved by many studies (Abreu et al., ; Rendon, Gratao, Salva, Azevedo, & Bragagnolo, ; Selmar et al., ). However, some recent studies have presented a different approach and concluded that coffee beans stored in parchment show little variation in color and in the organoleptic attributes of coffee (Abreu et al., ; Selmar et al., ), which may be due to a shielding effect and having less exposure to the outside environment.…”

“…Some authors also related flatness, slackness, and cup quality of coffee to the viability of coffee seeds (Sivetz & Desrosier, ), which was later approved by many studies (Abreu et al., ; Rendon, Gratao, Salva, Azevedo, & Bragagnolo, ; Selmar et al., ). However, some recent studies have presented a different approach and concluded that coffee beans stored in parchment show little variation in color and in the organoleptic attributes of coffee (Abreu et al., ; Selmar et al., ), which may be due to a shielding effect and having less exposure to the outside environment. Selmar and team also investigated the relationship of viability, processing type, and nonvolatile compound profile with storage (22 °C, 63% RH for 2 years) and established that the level of hexoses (that is, glucose and fructose) decreases over time in all types of processed coffee beans; however, fewer corresponding concentration differences were noted in wet‐processed green coffee beans.…”