31 Accepted: 03/11/2023, Revised: 22/01/2024, Published: 31/01/2024
EFFECT OF FERMENTATION TIME AND ROASTING TEMPERATURE ON THE CHARACTERISTICS OF WINE COFFEE ARABICA SEMERU
Jaya Mahar Maligan, Swandayani Utami Kosasih, Mochamad Nurcholis, Feronika Heppy Sriherfyna
Departement of Food Science and Biotechnology, Agricultural Technology Faculty, Universitas Brawijaya
Veteran Street, Malang, 65145 East Java Indonesia
*Corresponding Author, Email: [email protected] ABSTRACT
This study was conducted to identify the best fermentation period and roasting temperature for semeru arabica wine coffee. This study used the factorial RSBD research approach (three levels of roasting temperature and four levels of fermentation duration).
Physicochemical and organoleptic data were analyzed using ANOVA 5%, LSD 5%, and HSD 5%. Then, the best treatment's ash alkalinity, coffee juice content, and caffeine level were assessed. According to the study, the fermentation period has impact on the moisture level of green beans, the moisture and ash content of roasted beans, acidity, body, and balance. The water and ash content of roasted beans, aroma, flavor, acidity, aftertaste, body, balance, and overall attribute, are influenced by the roasting temperature. Then the interaction between factors significantly affects the water content of roasted beans, flavor, acidity, and body. The best treatment achieved a total score of 81.83 (40 days, 200 °C).
Keywords: Coffee characteristics, Fermentation, Roasting, Wine coffee INTRODUCTION
According to BPS (2021) coffee is the country's largest foreign exchange earning export commodity apart from oil and gas. The domestic coffee market also continues to increase, both from the production level which reached 794.8 thousand tons in 2022 (Mustajab & Bayu, 2023) and the consumption level in Indonesia which according to the International Coffee Organization (ICO) reported by Affandi (2021) has increased over the past five years to reach 50.97% of production in 2018-2019. This figure is the highest when compared to coffee- producing countries such as Brazil, Vietnam, Colombia, and Ethiopia. World coffee consumption is dominated by arabica (70%) according to Raharjo (2017) in Dairobbi et al.
(2018). The quality of taste and lower caffeine levels are the reasons for the dominance of arabica coffee consumption over the commonly cultivated robusta coffee (Nadhiroh, 2018).
The significant development of the coffee market in Indonesia shows the potential for Indonesia to become the largest and specialty coffee producer in the eyes of the world, especially the slopes of Mount Semeru which can produce good quality coffee (Putra, 2021).
Semeru Arabica coffee has characteristics of green apple, caramel, and brown sugar flavors when processed naturally and obtained a cupping test score of 76.81 (Maligan et al., 2022).
Where this score is not yet included in specialty coffee (score≥ 80) (SCA, 2021). One of the efforts to improve the quality of coffee flavor is to utilize fermentation technology such as the wine method (Dairobbi et al., 2018; Ismail Sulaiman et al., 2021).
The wine method is a modification of the natural method in which the wine method involves maceration and a longer fermentation duration compared to the natural method (Ramadhan & Maligan, 2018). The difference in the process encourages facultative anaerobic
32 fermentation by LAB and yeast/hamir (Silva, 2015; I. Sulaiman & Hasni, 2022). Wine fermentation can have an impact on taste, namely reducing bitterness and improving the taste of coffee such as the emergence of wine-like flavors due to complex compounds formed during fermentation (Dairobbi et al., 2018; Ismail Sulaiman et al., 2021). The esterification process of caffeine during fermentation is one of the processes that produce better aroma and flavor (Kristiyanto et al., 2013). The formation of aromatic compounds that cause wine-like flavors does not eliminate the original taste of the coffee itself. Therefore, the fermentation process can be an alternative to improve the quality and price of coffee products (Dairobbi et al., 2018;
Haile & Won, 2019; Ramadhan & Maligan, 2018; Ismail Sulaiman et al., 2021). However, flavor defects such as fermented or stinker can be produced if the fermentation process is not correct (Yusianto & Widyotomo, 2013).
In addition to the fermentation process, the flavor quality of brewed coffee is also influenced by the roasting process (Iflah & Dewi, 2019). The roasting process is an important process where pyrolysis will occur in coffee beans which causes the formation of volatile compounds in coffee. In addition, the roasting process will also cause Maillard and caramelization processes to occur which also affect the aroma and taste of coffee (Aliah et al., 2015; Münchow et al., 2020). Therefore, it is necessary to test the quality both according to taste and physicochemical characteristics of wine coffee processed with different fermentation lengths and roasting temperatures so as to obtain the effect of both factors on wine coffee characteristics as well as the best fermentation length and roasting temperature for Semeru Arabica coffee.
METHODOLOGY Materials
The materials used include ripe red Semeru Arabica coffee cherries as the main raw material obtained from plantations in Ampelgading District, Malang Regency. Roasted bean arabica semeru natural, roasted bean arabica arjuna Honey to Red, roasted wine coffee arabica arjuna, roasted wine coffee robusta arjuna obtained from Alir Coffee Malang as samples for sensory training. Mineral water, sugar, salt, citric acid, caffeine powder, MSG, CMC, pasteurized milk, palm sugar essence, caramel essence, chocolate essence, peanut essence obtained from Sensoflavo Kit for selection and panelist training. 3% H2O2 solution, 0.5 N HCl solution, 0.5 N NaOH solution, PP (Phenolphthalein) indicator, methanol, caffeine standard, distilled water, and filter paper for chemical testing of roasted beans coffee wine powder.
Tools
The tools used in this research are 10 kg plastic, 25 kg gunny sack, raffia rope, and huller machine to produce green bean coffee wine, Nor brand roasting machine with a capacity of one kg to produce roasted bean coffee wine. Cupping cups, cupping spoons, cupping forms, pens, grinding machines, scales, kettles, paper cups, questionnaires for panelist selection, basic taste and aroma test forms, plastic cups for organoleptic preparation and testing, while for physical and chemical testing of coffee, analytical scales are needed, Petri dish, spatula, crucible, electric oven, furnace, burette, 250 mL Erlenmeyer flask, 10 mL measuring pipette, 500 mL beaker glass, electric stove, 500 mL volumetric flask, glass funnel, 50 mL measuring pipette, dropper, desiccator, HPLC, test tube, vial, 50 µL syringe, membrane filter, and vacuum filter.
Research Design
The research was conducted by applying a 2-factor Randomized Group Factorial Design (RAKF) pattern. Factor I was fermentation duration (10 days, 20 days, 30 days, and 40 days) and factor II was roasting temperature (190˚C/light, 200˚C/medium, and 210˚C/dark).
The research was conducted to determine the physicochemical and organoleptic characteristics of semeru arabica wine coffee. Sensory tests were conducted using trained
33 panelists and referring to the SCA rules, namely the cupping test (Specialty Coffee Association) (SCA, 2021). The data obtained were then processed using ANOVA analysis with a 95%
confidence interval and will be followed by a 5% BNT (Fisher) test if there is a significant effect of the factor or 5% BNJ (Tukey) if the interaction between factors significantly affects the results. The best treatment is determined based on the total cupping test score (Dairobbi et al., 2018).
Research Stages
There are four stages of research. The first stage is the manufacture of green beans samples of Semeru Arabica wine coffee (Modification from Ramadhan, 2021) which are analyzed for physical quality and moisture content. The second stage is making samples of roasted beans of Semeru Arabica wine coffee (Modification of Anisa et al., 2017) which are analyzed for physical quality and water content. Which is analyzed physically, water content, and ash content. The third stage is testing the taste characteristics of Semeru Arabica wine coffee brewing as many as 10 attributes using trained panelists (SCA, 2021). Trained panelists are obtained by conducting a recruitment, selection, and training process (Modification of Rahmadhani and Fibrianto (2016), DLG (2017), Gutierrez and Barrera (2015), Mayasari et al.
(2017), Maulidiah and Fibrianto (2019), Wulandari (2019)). The fourth stage is the determination of the best treatment which is carried out further analysis in the form of ash, coffee juice, and caffeine content (BSN, 1992, 2004).
Methods
The preparation of coffee wine samples uses the spontaneous fermentation method by aging in a cool, dry, and dark environment for 10 days, 20 days, 30 days, 40 days on whole red (ripe) coffee cherries that have first been cleaned, sorted, and mined (Modified Ramadhan, 2021). After the fermentation time is reached, final drying is carried out with the help of solar heat until the moisture content of the coffee becomes around 10-12% and then hulled. The green beans obtained were then roasted with three temperatures (190˚C/light, 200˚C/medium, and 210˚C/dark) at each fermentation duration and roasted beans samples were obtained (Modified Anisa et al., 2017). Samples of green beans and roasted beans produced were then analyzed for chemical physical properties and organoleptic analysis of brewed coffee. Analysis of physical properties includes appearance, taste, odor in general and also the value of coffee defects (specifically green beans) (BSN, 1992). Chemical analysis includes gravimetric moisture content using an oven and gravimetric ash content (roasted beans) (BSN, 1992).
Furthermore, organoleptic analysis was conducted using the cupping test method using 15 trained panelists and procedures according to the SCA. Based on the cupping score, the best treatment (highest score) was selected for further testing of ash, coffee essence and caffeine content (BSN, 1992).
Analysis Procedure
Analysis of Physicochemical Characteristics of Green Beans
The procedure for analyzing the physicochemical characteristics of green beans is based on SNI 01-2907-2008 on coffee beans which includes physical condition, moisture content, and coffee defect value.
Analysis of Physicochemical Characteristics of Roasted Beans
The procedure for analyzing the characteristics of roasted beans is based on SNI 01- 3542-2004 on coffee powder and SNI 01-2891-1992 on how to test food and beverages which include physical conditions, moisture content, and ash content.
Organoleptic Analysis of Brewed Coffee
The organoleptic analysis procedure is based on the rules published by the SCA (Specialty Coffee Association) and assesses 10 sensory attributes (SCA, 2021)
34 Determination and Testing of Best Treatment
Determination of the best treatment is based on the total score on 10 sensory attributes.
The best treatment is the treatment that gets the highest total cupping score (Dairobbi et al., 2018; Ismail Sulaiman et al., 2021). After getting the best treatment, the coffee powder samples were then subjected to further tests, namely ash alkali, coffee essence, and caffeine content which were carried out based on and compared with SNI 01-3542-2004 regarding coffee powder.
RESULTS AND DISCUSSIONS
1. Analysis of Physicochemical Characteristics of Green Beans
Based on the test results, it is known that the green beans of Semeru Arabica wine coffee have met the requirements of SNI 01-2907-2008 on all parameters. Where no live insects were found and the beans smelled rotten and moldy in all treatments and the water content was below 12.5%. The test results of water content and defect value of green beans are listed in Table 1. Moisture content tends to decrease along with the longer the fermentation process occurs. The highest water content was obtained by wine coffee green beans with a fermentation time of 10 days, which amounted to 11.36% and the lowest water content was obtained with a fermentation time of 30 days, which amounted to 7.52%. Where the decrease in water content is caused by the longer the fermentation process, the greater the degradation process in coffee beans. This degradation causes the pores of the coffee beans to become more open so that when drying, the water from inside the coffee beans becomes easier to evaporate and causes the water content to become smaller / less (Barus, 2019; Zainuddin &
Tomina, 2021). The results of quality classification based on defect value, the best data obtained is with a defect value of 21 (10 days of fermentation) which is still classified into quality 2 (defect value: 12-25) and the lowest quality obtained is quality 3 (defect value: 26-44). The defect value is dominated by broken beans, which are incomplete beans that are equal to or less than 1/4 of the whole bean (BSN, 2008). This type of defect can be caused by limited facilities such as when hulling or removing the horns and epidermis from coffee beans obtained when the coffee fruit is still young (Rini et al., 2017).
Table 1. Green Beans Test Results based on SNI
Fermentation Time Criteria Result SNI
10 days
Moisture content (%)*
11.36 ± 0.05a
Max. 12.5
20 days 9.14 ± 0.29b
30 days 7.52 ± 0.08c
40 days 7.74 ± 0.13c
10 days
defect value
21.00 Quality 2
20 days 28.65 Quality 3
30 days 26.80 Quality 3
40 days 27.25 Quality 3
* Results are means (n=3), numbers after ± are standard deviations, and different notations indicate significant differences (α = 0.05).
2. Analysis of Physicochemical Characteristics of Roasted Beans
Physical and chemical testing of roasted beans of Arabica wine coffee is based on the quality standards of SNI 01-3542-2004 on ground coffee and SNI 01-2891-1992 on how to test food and beverages. Based on the test of physical conditions which include odor, taste, and color organoleptically, all treatments are declared normal and have met the requirements of SNI. While the chemical test results can be seen in Table 2, Table 3, and Table 4.
35 Table 2. Moisture Content of Roasted Beans of Arabica Wine Coffee
Sample Moisture Content (%) SNI
10/L 3.32 ± 0.04a
Max. 7
10/M 2.92 ± 0.03c
10/D 2.62 ± 0.01d
20/L 3.23 ± 0.01ab
20/M 2.90 ± 0.07c
20/D 2.68 ± 0.01d
30/L 3.06 ± 0.05bc
30/M 2.90 ± 0.01c
30/D 2.50 ± 0.04d
40/L 3.13 ± 0.06ab
40/M 2.89 ± 0.06c
40/D 2.60 ± 0.10d
*Results are means (n=3), numbers after ± are standard deviations, and different notations indicate significant differences (α = 0.05).
Note: L = light, M = medium, D= dark
Table 3. Test Results of the Effect of Fermentation Duration on Ash Content of Roasted Beans
Fermentation Time Ash Content (%) SNI
10 days 4.13 ± 0.08a
Max. 5
20 days 4.01 ± 0.14b
30 days 3.66 ± 0.03c
40 days 3.10 ± 0.05d
*Results are means (n=3), numbers after ± are standard deviations, and different notations indicate significant differences (α = 0.05).
Table 4. Test Results of the Effect of Roasting Temperature on the Ash Content of Roasted Beans Roast Temperature Ash Content (%) SNI
190˚C (light roast) 3.65 ± 0.44a
Max. 5 200˚C (medium roast) 3.74 ± 0.47a
210˚C (dark roast) 3.78 ± 0.49b
*Results are means (n=3), numbers after ± are standard deviations, and different notations indicate significant differences (α = 0.05).
Moisture content for all samples have met the standard of less than seven percent.
Water content tends to decrease with increasing fermentation duration and roasting temperature or can be said to be inversely proportional. Where the lowest water content results were obtained from samples with a fermentation time of 30 days and a dark roasting level.
While the highest water content was obtained from samples with a fermentation time of 10 days and a light roasting level. When the variance test was conducted, the length of fermentation and roasting level had a significant effect on the water content of roasted beans and there was a real interaction between the two factors at the 5% real level. The decrease in water content that occurs is caused by the process of degradation of coffee beans which will be greater when the duration of fermentation is longer and causes the pores of the coffee beans to become more open so that when drying, the water from inside the coffee beans becomes more volatile and causes the water content to become smaller / less (Barus, 2019;
Zainuddin & Tomina, 2021). The roasting process that uses heat will also evaporate water so that the higher the roasting level, the more water can be evaporated (Mardjan et al., 2022).
The ash content obtained Table 3 and Table 4 also met the SNI standard of less than five percent. When the variance test was conducted, the two factors, namely fermentation duration and roasting temperature, both had a significant effect on ash content. The trend of
36 ash content was similar to that of moisture content in the fermentation duration factor, but inversely proportional to the roasting level factor. The longer the fermentation duration, the lower the ash content due to fermentation which can cause the degradation of components from coffee beans accompanied by the pores of the coffee beans that are increasingly open.
So that the minerals contained in coffee beans become more easily dissolved out along with water during the drying process (Izzati et al., 2022; Zainuddin & Tomina, 2021). Meanwhile, the increase in roasting temperature will increase the ash content due to the increasing number of volatile components and water that evaporate along with the increase in roasting temperature (Edvan et al., 2016).
3. Organoleptic Analysis
a. Formation of a Team of Trained Panelists
The formation of the trained panelist team was carried out through several stages, namely panelist recruitment, panelist selection, and panelist training (threshold test, coffee sensory vocabulary training, and intensity test). Through the panelist recruitment process, 26 potential panelists were obtained with a general profile as shown in Table 5.
Table 5. General Profile of Panelist Candidates
No Characteristics Result
1 Gender 16 man and 10 women
2 Age 18 – 22
3 Occupotion Student
4 Domicile Malang
All prospective panelists then take part in selection in the form of basic taste and aroma testing. At this stage, all prospective panelists will be tested on the recognition of five basic flavors (sweet, salty, sour, bitter, and umami) and four aromas commonly found in coffee (palm sugar, caramel, chocolate, and peanut). Through this selection process, 15 panelists were obtained who could proceed to the training stage with a correct score of ≥80%.
Then the panelist training stage is carried out which includes the threshold test, coffee sensory vocabulary training, and intensity test before the actual organoleptic testing of samples. Based on the threshold test Table 6, it is known that the lowest group Best Estimate Treshold (BET) is obtained from the umami flavor (MSG solution), which is 0.01%. This lowest BET may indicate that panelists tend to be most sensitive in detecting umami flavors (Hasanah et al., 2014). The flavor with the highest group BET was obtained from the sweet flavor (sugar solution) which was 0.5%. The individual BET on sweetness was also 0.5% for all panelists, which means that sweetness can be detected by all panelists at a minimum concentration of 5 g/L solution. In this basic flavor BET result, not all individual BETs have the same value between panelists. This result shows that the level of sensitivity of each individual's sense of taste is different. The level of sensitivity of the sense of taste to certain flavors is influenced by several factors that can be divided into internal factors and external factors. Internal factors include genetics while external factors include lifestyle (diet and smoking habits) (Lawless &
Heymann, 2010).
Table 6. Threshold Testing Results
Taste BET Individual BET Grup
Sweet 0.50 0.50
Sour 0.01 – 0.04 0.01
Salty 0.10 – 0.16 0.11
Bitter 0.01 – 0.04 0.02
Umami 0.01 – 0.02 0.01
Note: data is the result of calculation by BET method ASTM E679
37 Coffee sensory vocabulary training was then conducted for coffee flavor recognition, cupping test method, and coffee sensory attribute vocabulary uniformity after panelist were trained with the sensory kit, coffee lexicon and flavor wheel. The results of this training can be seen in Table 7.
Tabel 7. Cupping Test Training Results
Sampel Aroma Flavor Body Acidity
Arabika Arjuna (Honey to Red)
Nutty, chocolate,
fruity - Thin to medium Thin to medium
Robusta
Arjuna (wine) Fruity (jack fruit) Brown sugar,
chocolate Thin to medium Thin to Medium Arabika Arjuna
(wine)
Nutty, chocolate, fruity
Winey, savory,
citrus, teh Thin to medium Medium
The last training stage is in the form of coffee sensory attribute intensity training which includes aroma, flavor, and body. This training was conducted to train the consistency of panelists both as a group and individually. Data were analyzed using Pearson Correlation (PCC) test and paired t-test, the results of which are listed in Table 8.
Table 8. Panelist Intensity Rating Consistency Test Results
Attribute PCC P-value
Aroma
Peanut (Nutty) 0.61 0.50
Orange 0.82 0.99
Chocolate 0.62 0.76
Flavor
Sour 0.81 1.00
Bitter 0.88 1.00
Sweet 0.82 0.93
Salty 0.95 1.00
Body
UHT Milk 1.00 1.00
CMC 0.81 1.00
Notes: Critical value limit (PCC): 0.514 and data is the result of 2 replicates and 15 panelists.
Based on the data obtained, it can be stated that the panelists have been consistent for all existing references both individually and in groups. This is because all PCC values for each reference have passed the critical limit of 0.51 so it can be said that each individual panelist has been consistent in giving an assessment. Then the p-value on all references is also more than 0.05, which means that the answers of the panelists for the intensity of a reference are not significantly different from each other with a 95% confidence interval or are consistent as a group.
b. Cupping Test
In this research, the cupping test rules used were adapted from the SCA (Specialty Coffee Association). Some of the sensory parameters tested or evaluated are fragrance/aroma, flavor, aftertaste, acidity, body, balance, uniformity, sweetness, clean cup, and overall. The overall cupping test scores can be seen in Table 9.
38 Table 9. Taste Profile of Semeru Arabica Wine Coffee
Attribute 10/L 10/M 10/D 20/L 20/M 20/D 30/L 30/M 30/D 40/L 40/M 40/D Aroma 7.80 7.73 7.45 7.78 7.82 7.63 7.68 7.72 7.75 7.70 7.77 7.72 Flavor 7.45 7.62 7.50 7.42 7.63 7.52 7.43 7.52 7.48 7.80 7.58 7.33 Aftertaste 7.62 7.68 7.43 7.37 7.58 7.33 7.48 7.73 7.45 7.57 7.52 7.53 Acidity 7.82 7.55 7.30 7.65 7.83 7.47 7.60 7.43 7.38 7.53 7.92 7.55 Body 7.37 7.47 7.33 7.43 7.28 7.40 7.33 7.57 7.58 7.33 7.52 7.68 Balance 7.47 7.55 7.52 7.70 7.72 7.62 7.63 7.80 7.47 7.37 7.62 7.53 Uniformity 9.07 8.93 9.60 9.33 9.20 8.80 9.33 9.20 9.33 8.93 9.33 9.20 Clean Cup 9.73 9.87 9.47 9.60 9.60 9.60 9.60 9.47 9.60 9.60 9.60 9.47 Sweetness 9.60 9.20 9.73 9.20 9.60 9.73 9.60 9.87 9.73 9.33 9.87 9.73 Overall 7.47 7.70 7.48 7.48 7.68 7.40 7.55 7.72 7.52 7.53 7.78 7.55 Defect 0.40 0.27 0.53 0.27 0.27 0.40 0.53 0.40 0.67 0.67 0.67 0.67 Total 80.98 81.03 80.28 80.70 81.68 80.10 80.72 81.62 80.63 80.03 81.83 80.63
Description: data is the average of 15 panelists
Notes: fermentation time = 10,20,30 and 40 days, rosating level: L=light, M=medium, D=dark The data obtained when analyzed by ANOVA with a 95% confidence interval showed that the length of fermentation had a significant effect on the attributes of acidity, body, and balance Table 10. While the roasting temperature factor significantly affects the attributes of aroma, flavor, acidity, aftertaste, body, balance, and overall Table 11. The interaction of the two factors significantly affected the attributes of flavor, acidity, and body Table 12.
Table 10. Effect of Fermentation Duration on Various Attributes
Duration of Fermentation Attribute
Acidity Body Balance
10 days 7.55ab 7.39bc 7.51b
20 days 7.65a 7.37c 7.68a
30 days 7.47b 7.49ab 7.63a
40 days 7.67a 7.51a 7.51b
Note: data is the average value of 15 panelists and different notations indicate significant differences (α = 0.05).
Based on further tests, the longer the fermentation, the higher the acidity, body, and balance scores. However, the balance attribute after experiencing an increase will experience a decrease. The fermentation process can increase acidity due to the formation of compounds during fermentation such as reducing sugars, amino acids, organic acids, trigonelline, chlorogenic acid, lipids, and peptides. In addition to lactic acid and acetic acid produced when fermentation is carried out for a long duration (Haile and Won, 2019; Silva, 2015; Vaughan et al., 2015; Cardoso et al., 2021). Meanwhile, in the body parameter, the increase in score is caused by the formation of reducing sugars, amino acids, lipids, peptides, and organic acids during fermentation which can affect the body (Soesanto, 2020; Towaha et al., 2015). The increase in balance score is due to the decomposition of macromolecules such as carbohydrates and proteins into simpler components such as simple sugars and organic acids by yeast and bacteria during fermentation. Carbohydrate breakdown occurs as a result of the enzymatic activity of carbohydrase and pectinase which can produce reducing sugars (glucose and fructose) (Wang, 2012; Silva et al., 2015; Haile and Won, 2019).
39 Table 11. Effect of Roasting Temperature on Various
Roast Temperature Attribute
Aroma Flavor Acidity Aftertaste Body Balance Overall 190˚C/ light roast 7.74a 7.53ab 7.65a 7.51b 7.37b 7.54b 7.51b 200˚C/ medium roast 7.76a 7.59a 7.68a 7.63a 7.46ab 7.67a 7.72a 210˚C/ dark roast 7.64b 7.46b 7.43b 7.44b 7.50a 7.53b 7.49b Note: data is the average of the scores of 15 panelists and different notations indicate significant differences (α = 0.05).
Table 12. Interaction Effect of Fermentation Duration with Roasting Temperature on Various Attributes
Duration of
Fermentation Roast Temperature Attribute
Flavor Acidity Body
10 Days
190˚C/ light roast 7.45b 7.82abc 7.37ab
200˚C/ medium roast 7.62ab 7.55bcd 7.47ab
210˚C/ dark roast 7.50ab 7.30d 7.33b
2 Days
190˚C/ light roast 7.42b 7.65abcd 7.43ab
200˚C/ medium roast 7.63ab 7.83ab 7.28b
210˚C/ dark roast 7.52ab 7.47cd 7.40ab
30 Days
190˚C/ light roast 7.43b 7.60abcd 7.33ab
200˚C/ medium roast 7.52ab 7.43d 7.57ab
210˚C/ dark roast 7.48ab 7.38d 7.58ab
40 Days
190˚C/ light roast 7.80a 7.53bcd 7.33ab
200˚C/ medium roast 7.58ab 7.92a 7.52ab
210˚C/ dark roast 7.33b 7.55bcd 7.68a
Note: data is the average overall score of 15 panelists and different notations indicate significant differences (α = 0.05).
Roasting temperature can affect aroma due to the activation of simple compounds formed during fermentation (Aliah et al., 2015; Haile & Won, 2020; Münchow et al., 2020). Such as furan compounds that present caramel, hazelnut, and sugar aromas. Ketone compounds create sour, buttery, caramel aroma sensations. Aldehyde compounds produce caramel-like aromas, phenol compounds present the aroma sensation of citrus, while pyrazine compounds present hazelnut and earthy aroma sensations (Galarza & Figueroa, 2022; Hanasasmita, 2018;
Wenny B Sunarharum et al., 2014; Wenny Bekti Sunarharum et al., 2019).
Flavor is also affected by roasting temperature because during roasting the flavor can become more complex due to the Maillard process that occurs and also the creation of sweetness due to sugar carbonation (Galarza & Figueroa, 2022; Hanasasmita, 2018; Wenny B Sunarharum et al., 2014; Wenny Bekti Sunarharum et al., 2019). However, the roasting process for too long can create an unfavorable flavor due to over-roasting of the coffee beans and produce a burning taste and also contribute to the over-reaction of phenols in coffee beans with a long roasting duration (Rini et al., 2017). Furthermore, the roasting process can reduce the acidity level of the brewed coffee and give a "flat" or less diverse impression to the coffee.
According to Münchow et al. (2020), the roasting process affects the transformation of biochemical components that can affect the acidity of brewed coffee. According to Freeman (2013), the roasting process can increase body as the roasting temperature increases due to the formation of melanoidin during the Maillard process. Melanoidin can increase body because it has amphiphilic properties of hydrophobic moieties (furan and pyrrole) and negatively charged hydrophilic moieties. The presence of polysaccharides in melanoidin can also act as a body enhancer by binding water (Feng et al., 2023). In addition, the roasting process to the dark level causes the release of the natural fat of the coffee beans which
40 contributes to the milky sensation which can improve the mouthfeel of coffee brewing (Soesanto, 2020; Towaha et al., 2015). The interaction of the two factors affecting flavor, acidity, and body attributes is due to the formation of flavor precursors during the fermentation process, which are activated during roasting in addition to the increase in body with increasing roasting temperature.
4. Determination and Testing of the Best Treatment
The best treatment is obtained by considering all the test attributes/parameters tested.
The scores on the ten attributes will be summed up and become the total score on the cupping test (Dairobbi et al., 2018; Ismail Sulaiman et al., 2021). The highest total score Table 10 was obtained by the 40 days coffee wine sample with a medium roasting level with a total score of 81.83 which can be categorized as specialty coffee (>80.00) (SCA, 2021). Coffee fermentation for 40 days is assumed to be quite burdensome for farmers and roastery because it is less- economical.
Furthermore, chemical characteristics testing was carried out on the best treatment presented in Table 13. Based on the results of chemical characteristics testing and the three existing parameters, the sample has met Requirement I for the caffeine test criteria and meets Requirement II for all criteria.
Table 13. Chemical Test Results of the Best Treatment
Criteria Unit Result Requirement I Requirement II Ash alkalinity 𝑚𝑙 𝑥 𝑁. 𝑁𝑎𝑂𝐻
100 𝑔 64.09 ± 1.15 57 – 64 min. 35
Coffe juice % b/b 19.04 ± 1.31 20 – 36 max. 60
Coffee
(anhydrous) % % b/b 1.90 ± 0.19 0.9 – 2 0.45 – 2
Notes: results are means (n=2) and ± indicates standard deviation.
CONCLUSIONS
All samples produced have met the SNI quality requirements regarding coffee beans and coffee powder. Based on ANOVA testing, the length of fermentation affects the moisture content of green beans, moisture content and ash content of roasted beans, acidity, body, and balance attributes. Then the roasting temperature significantly affects the water content and ash content of roasted beans, attributes of aroma, flavor, acidity, aftertaste, body, balance, and overall. The interaction between factors significantly affects the water content of roasted beans, flavor attributes, acidity, and body. In addition, the best treatment was obtained, namely 40 days of fermentation with a roasting temperature of 200°C which has a total score of 81.83 which has been categorized as specialty coffee.
ACKNOWLEDGMENT
Thanks to the Faculty of Agricultural Technology Brawijaya University for funding this research.
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