Physical quality and flavor profile of arabica coffee beans (Coffea arabica) from Seko, South Sulawesi as a specialty coffee

Physical quality and taste are important parameters for determining the status of coffee beans as specialty coffee. This research aims to determine the status of Seko coffee by identifying the physical quality and taste. Arabica coffee samples were taken purposively and then processed following specialty coffee processing standards (SS) and processing carried out by farmers (NS). The research data was evaluated using a Randomized Block Design using Windows SAS V9.4. The parameters measured are physical quality and taste based on SNI 01-2907-2008 and specialty coffee standards according to the Specialty Coffee Association of America (SCAA). The identification results showed that in both treatments there were no live insects, foul smelling seeds and smelling like mold, and no dirt found. Standardly processed coffee (SS) has a defect value of 6.1, water content 8.40%, flavors specifications: brown sugar, caramelly and flowery, cup test score 85.38, while non-standard processing (NS) has a value defects 145.5, water content 10.4 %, taste specifications caramelly, herbal, and spicy with a cup test score of 83.75. It was concluded that standard processing (SS) produces a cup test value of > 80 and a defect value of ˂ 8 so it qualifies as premium quality specialty coffee.


Introduction
Coffee is an important economic commodity in world trade.Indonesia is one of the fourth largest coffee producers in the world, or around 6.63% of the world's total coffee production after Brazil (35.27%),Vietnam (18.23%), and Colombia (8.36%) [1].
The need for coffee is increasing in line with habits and lifestyles that tend to use coffee as an accompanying drink in various activities.This will encourage competition, especially in creating various innovations to produce superior quality and flavour.
One type of quality coffee that is well known and has economic prospects is specialty coffee.Specialty coffee is the best quality coffee and has a distinctive flavor character.Specialty coffee is a 1338 (2024) 012048 IOP Publishing doi:10.1088/1755-1315/1338/1/012048 2 term given by the International Coffee Organization (ICO) which refers to several coffee populations grown in specific geographical conditions, which produce coffee with distinctive flavor and aroma characteristics with consistent quality [2].The distinctive flavor of specialty coffee is generally found from the Arabica species, because it has a strong flavor, and tends to be sour and sweeter with a hint of fruit and chocolate, compared to Robusta coffee with a more bitter taste.Several studies have proven the effect of altitude on physical quality [3] and Altitude also affects the taste of Arabica coffee [4].
In general, specialty coffee grows well in areas with an altitude of > 1000 meters above sea level (m a.s.l.) and it is known that the Arabica species grows well at 1,000 -1,700 m a.s.l. with an average annual temperature of 17 -21 0 C, while the Robusta type lives at an altitude of 400-700 meters above sea level with an average temperature annual 20 -24 0 C [5,6].
One of the Arabica specialty coffee production areas in Indonesia is located in South Sulawesi, with production centres in Tana Toraja and Enrekang districts.Coffee from this region is known internationally for its distinctive aroma with low acidity, smooth, very soft mellow and good body [2].
Apart from Toraja and Enrekang coffee, coffee which is strongly suspected to have characteristics as specialty coffee, has also been widely cultivated in several highlands in the northern part of South Sulawesi, such as in Seko district, North Luwu Regency, which is known as the Seko Coffee Centre.
The Seko region is in located in the cool expanse of the Latimojong mountains with an altitude of around 1,113 to 1,485 m.a.s.l [7].Geographically, the Seko area at this altitude is dominated by Arabica coffee, with production reaching 558.8 tonnes from a planting area of 459 Ha, or with a productivity of 1.2 tonnes/ha [8].
According to testimonials, Seko Arabica coffee has received recognition from various groups at home and abroad as specialty coffee because it has a distinctive aroma and taste, but in trade transactions it is still categorized as regular quality coffee.To designate Seko coffee as specialty coffee, it still needs to be verified through rigorous research and evaluation so that it can be scientifically justified.
The process to obtain specialty quality coffee starts from when the coffee is grown or cultivated, harvested, post-harvest processing, brewed, until the consumer tastes it.
The quality of specialty coffee is determined through rigorous physical and flavour testing and proven by the results of an assessment by a certified Q Grader based on international specialty standards issued by the Specialty Coffee Association of America (SCAA).The flavor attributes assessed primarily for Arabica coffee are fragrance and aroma, flavor, after taste, acidity, body, balance, uniformity, clean cup, sweetness, and overall as well as taint/defect [9,10].A coffee product can finally be classified as specialty coffee if the final score obtained from cup testing is at least 80 on a scale of 100 [11].
Physical quality and flavour are the main parameters that can be used to measure specialty coffee standards.The importance of assessing physical coffee quality is because it is a series of several factors that influence it, such as species, place of growth, age of harvest, post-harvest handling methods, and processing before the coffee is brewed.Meanwhile, the quality of the coffee flavor is the final parameter that is determined after going through the physical quality assessment, because all factors that affect the physical quality will have an impact on the quality of the coffee flavor.
Several previous research results related to the characteristics of local coffee and the influence of post-harvest processing on its quality have been widely reported but are still limited to assessing the physical quality of green beans [12,13], while information regarding the quality of the coffee flavor from the brewing results is still very less.Besides that, the flavor characteristics of several local coffee species, such as Seko Arabica Coffee, are unknown and have not been scientifically or standardizedly verified.
Research to reveal the physical quality and flavor profile of Seko coffee is very important to prove that Seko coffee also has the potential to have quality as specialty coffee.This research aims to determine the quality status of coffee from Seko, South Sulawesi by evaluating the physical quality profile and flavor of coffee based on post-harvest processing treatment to be designated as specialty coffee.
The physical quality and flavor characteristics verified from this research will become a unique and standardized specialty for coffee produced from the Seko coffee production centre.

Sampling and Treatment Methods
Arabica cherry coffee fruit is taken from local farmers' harvest from 5 harvest locations at an altitude of 1,400 meters above sea level.Sampling is divided into 3 parts, namely: 1) Samples of coffee fruit (cherry) originating from the harvest of local farmers, then processed using the wet method according to specialty coffee processing standards from the Kalosi coffee centre in Enrekang Regency, South Sulawesi (Figure 1), or so-called standard processing treatment (SS).2) Samples of coffee fruit (cherry) originating from farmers' harvests are then processed using the natural method according to the habits of local farmers (Figure 2) or called non-standard processing treatment (NS).3) Green bean coffee samples taken from processed specialty coffee at the Kalosi Coffee Centre, Enrekang regency, South Sulawesi, or called comparison treatment (ES).
Processed results from standard (SS), non-standard (NS) and comparison treatments (ES) are in the form of dry coffee beans (green beans), which are then used as samples for physical quality assessment.Green Beans coffee from the three treatments is then roasted at medium level at a temperature of 180 ºC for 9ʹ.20ʺ.The roasted coffee is then ground into ground coffee and used as a sample for aroma and taste testing.

Specialty and Natural Coffee Processing
Specialty coffee processing follows Kalosai, Enrekang coffee processing standards, sequentially starting from: harvesting the red fruit (cheery), sorting the fruit logs, soaking/mining the fruit (to separate the red fruit that floats), peeling the skin of the cherry (pulping), fermenting coffee grains (during 12 -36 hours), Washing, drying grain coffee until half dry (moisture content 30 -40%), peeling (hulling) to produce rice coffee (green beans), drying green beans until moisture content 12%, sorting and storing green beans for quality assessment.
Natural coffee processing starts from; harvesting fruit, sorting fruit logs (to separate twigs, rocks, dirt), drying with skin (water content is uncertain), peeling dried fruit skin, drying, storing green beans for quality assessment.

Parameters and Testing
The physical quality assessment of coffee is determined based on SNI 01-2907-2008 which includes parameters; live insects, foul smelling seeds and smell like mold, dirt content, water content, and defect values; and assessment of flavour attributes using the "cupping test" method which is referenced from the specialty coffee quality standards according to the Specialty Coffee Association of America (SCAA).
Technically, taste assessment with a cup test was carried out by six certified people at the Indonesian Coffee and Cocoa Research Institute in Jember East Java.The process begins by roasting 150 grams of coffee sample at 200°C for 10 minutes, then immediately storing it for 12 hours in an airtight jar.Next, the coffee beans are coarsely ground using a grinder, then cupping/smelling them to get the aroma of the coffee.Next, 10 g of ground coffee is placed in a ceramic cup then brewed with 180 ml of hot water at a temperature of around 93°C and left for 4 -5 minutes.Clean the foam on the surface using a spoon.After the coffee temperature reaches 73˚C -78 ˚C then the coffee is ready to be analyzed/assessed by sipping.The taste attributes tested consisted of; The panelists' preferences include Sweetness, Acidity, Clean up, aftertaste, Balance, Body, Flavor, Fragrance, and Overall.The results of the cup score evaluation and taste notation were detached into four groups: 6.00 -6.75 = Good; 7.00 -7.75 = Very Good; 8.00 -8.75 = Excellent; and 9.00 -9.75 = Outstanding (SCAA, 2015).Next, the character or flavour impression that emerges is determined, such as brown sugar, caramelly, flowery, herbal, and spicy, and other characters.

Data processing
The research data were processed statistically using a group design.Analysis of variance (Anova) at p ˂ 0.05 level, and significant difference test or distance test using Duncan's multiple tests with Windows SAS System V9.4 application.

Physical Quality
In general, specialty coffee quality standards are determined based on a combination of general physical quality parameters of coffee beans as stated in SNI 01-2907-2008 and special parameters as stated in standards issued by the Specialty Coffee Association of America (SCAA).Physical quality is an important parameter needed to determine the status and economic value of a coffee product.The importance of physical quality assessment is as a reference for evaluating the causes of flavour defects after coffee is brewed.The physical quality of coffee assessed includes live insects, foul smelling seeds and smelling like mold, water content, impurity content, and defect value.The results of assessing the physical quality of coffee from various treatments can be seen in Table 1.

Live insects, foul smelling seeds and smell like mold, and impurity
The results of the research showed that physically there were no live insects, foul smelling seeds and smell like mold, and impurity on coffee beans from Seko processed using standard methods (SS) or those carried out at the farmer level (NS) (Table 1).Live insects are one of the indicators for determining defects in coffee beans, because the presence of live insects can result in damage to the coffee beans, the coffee beans being black and smelling bad.The presence of insects in coffee starts when the coffee berries are still on the tree or on coffee berries that have fallen and will last until the coffee is harvested.However, in this study no live insects were found during post-harvest processing.This indicates that Arabica coffee Seko at the on-farm level has not been contaminated with insects.

Water content
The requirements for water content in coffee beans are related to shelf life, cherry maturity level, and texture.The low water content of coffee beans will inhibit the activity of microorganisms, thereby impacting the shelf life and physical damage to the coffee beans.Coffee beans with a water content of >12.5% are easy to grow bacteria, fungus or mold, water content of ˂11% are easily brittle and break.
According to Lorey et al [14], if the beans are too dry (moisture content below 8%) it will cause the beans to lose their flavor or become more brittle so they will easily break when stripping the skin with a huller machine.
The results of the identification of the water content of coffee beans show that there are differences between standard processing methods (SS) and processing methods at the farmer level (NS).The water content of coffee beans with standard processing methods can be reduced by up to 50% compared to non-standard (NS) processing and specialty standard processing of Enrekang coffee (ES).
In this study, coffee beans with standard treatment had a water content of 8.4%, this value meets the SNI standard (12.5%) which is physically very dry so that structurally it will be easily brittle but compared to the low value of bean defects (value 6.1) shows that Seko coffee processed with standard treatment (SS) has a strong and compact physical texture of the beans.As a comparison with specialty coffee from Enrekang (ES), there is a difference in water content, where in the standard treatment (SS) the water content is lower than the comparison treatment (ES), but overall, it still qualifies the requirements of SNI 01-2907-2008.

Defect value
The value of coffee bean defects according to SNI 01-2907-2008, is divided into 6 quality groups: quality I with a maximum defect value of 11, quality II defect value 12 -25, quality III defect value 26 -44, quality IV defect value 61 -80, quality V defect value 81 -150, and quality VI defect value 151 -225.According to SCAA, the defect values are divided into Special Grade Quality (maximum defect value 5), Premium Grade (maximum defect value 8), Exchange Grade (defect value 9 -23), and Below Standard Grade (defect value 24 -86).
The results of the research show that there is a difference in the value of physical defects in Seko coffee, between the standard processing method (SS) and the farmer processing method (NS).Based on SNI 01-2907-2008, Seko Arabica coffee processed with standard treatment (SS) is classified as quality 1 with a defect value of 6.1 so that it meets the requirements for specialty coffee in the "premium grade" category, while coffee processed at the farmer level (NS) is classified as quality 5 but does not qualify as specialty coffee in any category because it has a defect score of 145.5.Compared with specialty coffee from Enrekang (ES), there is no difference with standard treatment (SS) where the defect values are both 6.1 and 5.5 (Table 1).
The requirements for specialty coffee in the "Special Grade" category according to SCAA standards, 2009, have a maximum defect value of 5 in 300 grams of coffee beans with the characteristics; does not contain major defects, such as black beans, unripe beans, dried spindle beans and dirt, thus Seko coffee with standard treatment (SS) meets the requirements for specialty coffee in the "Premium Grade" category.
Physically, coffee bean defects are characterized by the presence of holes in beans, broken beans, black beans, wrinkled beans, shiny green beans, rotting beans, dirt, and high acidity.Hollow beans are a form of physical defect that can occur due to insect activity, but from the results of this research, no live insects or hollow seeds were found from both treatments, so it can be stated that physical defects in coffee beans are caused by other factors such as fruit uniformity, ripeness, and post-harvest processing.The varying characteristics of coffee fruit based on shape and size can cause physical damage when pulping [15].
Harvesting coffee cherries that are unripe can cause shrinkage and brittleness of the beans, which will result in a poor physical appearance and breakability.The high value of physical defects in processing carried out by farmers (NS) indicates that there are harvests with varying levels of maturity.Apart from that, physical defects also occur due to uncontrolled post-harvest processing, especially at the sorting stage, where at this stage farmers only carry out manual sorting by separating dirt and foreign objects but have not carried out sorting to separate ripe cherry.Acute fermentation and poor drying can also cause physical defects characterized by black and dull coffee beans.
Defect coffee beans have a negative effect on the composition of chemical compounds, especially caffeine and reducing sugars, which will result in a decrease in flavor value.
The defect value in the standard processing treatment (SS) has a difference of 1.5 points from the standard "Special Grade" score, indicating that the problem of physical defects in Seko coffee can be overcome through improvements at the on-farm level, because the problem of physical defects is at the post-harvest level.has been controlled by standard processing methods.
In general, it can be concluded that there is a difference in the specialty grade of coffee from Seko due to processing treatments.Where the quality of Seko coffee increased from quality 5 to quality 1 with specialty qualifications.This shows that the quality of coffee from Seko has the potential to be improved from "Premium Prade" quality to "Special Grade" through improvements and optimization starting from cultivation, harvesting, to post-harvest processing.

Bean Size
In terms of bean size, there are differences between standard processing (SS) and farmer processing (NS).The SS treatment has a "large bean" size while the NS treatment has a "small bean" size.Apart from that, coffee from Seko with standard treatment (SS) has a larger bean size than the size of specialty coffee beans from Enrekang (ES), but based on SNI both are still classified as quality I.
The size of the coffee beans can change due to shrinkage during the drying process, especially for coffee beans that come from the harvest of immature coffee cherries.Coffee cherries that are harvested mature have a firmer texture than those harvested at a young age.Young coffee beans do not have a compact structure and tend to contain high water content so they will lose weight and size during postharvest processing.When compared with the standard specialty coffee produced by the coffee processing center in Enrekang (ES) which has a "Medium Bean" size, the difference in bean size is not caused by processing treatment but is more influenced by internal and external factors of the coffee plant itself.These internal factors can be in the form of inherited traits in coffee plants, such as production ability, clones, fruit size, and resistance to disease.Meanwhile, external factors are generally related to the environment where coffee grows, such as soil, climate, altitude, rainfall, temperature, wind conditions, protective trees, and maintenance methods [16].Although not identified in this research, it can be taken into consideration in determining the location of superior species for the development of specialty coffee.5

Flavor and aroma
Flavor and aroma are quality attributes of a coffee product that appear when it is smelled, brewed and served to consumers.The assessment of the taste and aroma of specialty coffee refers to the specialty coffee quality standards issued by the Specialty Coffee Association of America (SCAA) and is the final parameter after physical quality tests are carried out.
The results of the evaluation of the flavor attributes of Seko coffee beans and specialty coffee comparisons from Enrekang (Figure 3) show that coffee beans processed using standard methods (SS) and traditional processing methods (NS) have flavor quality at very good to excellent levels.
In terms of fragrance, flavor and body attributes, processing using the specialty standard (SS) method is superior to traditional processing methods (NS).Compared to specialty coffee from Enrekang (ES), standard processing (SS) has better falvor quality.
The fragrance attribute describes the level of liking in the form of the aroma of the coffee when it is still dry, and the aroma of the coffee when it is brewed with hot water.The evaluation results show that the standard processing treatment (SS) and the specialty coffee comparison treatment provide a very good level of liking with a score of 7,75 -8,03 (very good -Excellent).
In detail, the sweetness and clean up taste attributes for both treatments and comparisons had the highest quality (score 10.00).This shows that the sweetness dominates the sour taste (score 7.25-7.75),while the clean-up attribute with a score of 10 indicates that no taste defects were found from the beginning to the end of the assessment.The sour taste that appears with a medium value indicates that the fermentation and roasting process stages were carried out well according to specialty coffee processing standards.The source of the flavors formed is thought to come from the fermentation process and then interact to form new compounds during the roasting process.Devis et al [17] stated that organic acids are important compounds in the formation of taste and aroma after coffee is roasted.
In term of how long the coffee taste lasts (aftertaste), there is a similarity in the quality of both treatments and the comparison treatment, where the quality of the taste is at a very good level (score 7,63-7.88).This indicates that the flavor-producing compounds have interacted and accumulated properly during the processing process (fermentation, drying, roasting).This taste and aroma become stronger and lasts longer (aftertaste) when the coffee is brewed and consumed.This means that the coffee produced from both treatments tastes sweet with a strong sour taste, but in terms of acidity and the length of time the positive taste and aroma last (after taste), the standard treatment (SS) is more dominant than the non-standard treatment (NS) with scores of 7.75 and 7.88 respectively.
Flavor is a special character that describes a combination of fragrance, acidity, and aftertaste attributes.The evaluation results show that the standard processing treatment (SS) provides a very strong coffee aroma when the coffee is tasted and felt when the steam aroma flows from the mouth to the nose.A high flavor score in coffee processed with standard treatment (SS) illustrates the complexity of taste and smell which feels very strong when the coffee is enjoyed.The flavor characters that emerge from the flavor attributes of Seko coffee processed with standard treatment (SS) are brown sugar, caramelly and flowery, while traditional processing (NS) produces caramely, herbal, and spicy flavors.Comparative treatment for specialty coffee from Enrekang (ES) produces a flavor profile that is almost the same as the flavor profile of Seko coffee but has a different character or type.The flavor characters that appeared in the comparison treatment (ES) were brown sugar, vanilla and spicy.In terms of flavor characteristics, both of SS and NS treatments as well as the specialty coffee (ES) comparison have different flavor characteristics.
The difference between traditionally processed coffee beans and standard processing lies In the stages of harvesting, fermentation and drying.Farmers have not selected the ripeness of the cherry fruit, which results in flavor defects.Chemical Compounds such as chlorogenic acid, caffeine and polyphenols are not fully formed in immature coffee.Besides that, careless and inconsistent fermentation are a source of flavor defects, where at this stage coffee beans that are processed in a dry (natural) way tend to produce varied and imperfect flavors.
Partelli et al [18], stated that reducing sugar and non-reducing sugar are responsible for the formation of caramelly flavor and sweetness in brewed coffee.The sweet and sour flavors are related to the compounds that dominate the Arabica coffee type.Compounds that influence the taste of coffee are excellent, sugar, soluble solids content, chlorogenic acid, and caffeine [19].These compounds are changed during the fermentation process which then accumulates and is formed into a strong and unique flavor after going through the roasting process.
The body attribute is a thick or light taste when the coffee is tasted and felt between the tongue and the palate.A strong thick taste occurs in standard treatment (SS) with a score of 8.00 (excellent) and is different from specialty coffee from Enrekang (ES) with a score of 7.63.The thick taste in the body attribute is thought to be related to the strong sweetness attribute in Seko coffee which is processed using standard methods.The strong sweet taste is the result of the accumulation of carbohydrates formed during the coffee fermentation and roasting process.The high thickness of the body attribute results in a stronger aftertaste attribute value.This results in the coffee tasting thick (body) and lasting longer in the mouth (aftertaste).
A series of taste characters that include flavor, aftertaste, and body aspects with the right score on standard treatment (SS) produces a balanced coffee taste with a score of 7.88 (very good).In the traditional processing (SP) treatment, the balance attribute value fell to 7.63 (very good), which indicates that one of the flavors is lacking.An unbalanced taste in the balance attribute can occur because one of the overall flavors is missing, resulting in a flavor defect.The low balance attribute in processing treatment at the farmer level (NS) is the impact of high levels of physical defects in post-harvest processing.
Flavor defects can occur due to several factors, such as: fruit ripeness and uncontrolled post-harvest processing.Coffee cherry with a low level of maturity (green fruit and yellow fruit) has an incomplete chemical compound composition compared to coffee fruit with a high level of maturity (red fruit).Coffee that is harvested at maturity has a high flavor because it has complete flavor-forming compounds.A complex combination of various types of flavors produces a balance of flavors.So that if continued with the correct roasting and brewing process it will produce a distinctive flavor and aroma profile.According to Clarke [9] and Oliviera et al [20], that what influences the quality of (brewed) coffee includes cultivar, blend, production process and storage.In detail, the process includes from when the coffee beans (cherry) are harvested until the coffee beans (green beans) are ready to be processed, marketed, or stored.A taste score that is lower than standard treatment indicates that Seko farmers have not carried out processing consistently.
The overall assessment of the flavor attribute (overall) shows that the taste of Seko coffee processed with standard treatment (SS) is better than the taste of coffee processed by farmers (NS) and specialty coffee from Enrekang (ES), each with a score of 8.00 (excellent), 7.75 (very good), and 7.8 (very good).
The results of the coffee brew tested using the cup test gave a value of 85.38 for Seko coffee with standard processing (SS), where this value is higher than that required by the Specialty Coffee Standards issued by the Specialty Coffee Association of America (SCAA), namely > 80. Apart from that, traditional processing methods carried out by farmers (NS) also provide a cup test value of 83.75 or higher than required by the SCAA.Based on the description of the research results above, it can be stated that coffee from Seko has the potential to become a specialty coffee.The specialty coffee produced in this area is very different in terms of flavor characteristics from one treatment to another.This indicates that the origin of specialty coffee, apart from being influenced by location and altitude, is also influenced by processing treatments.The different and unique flavor characteristics of Seko coffee indicate the existence of a new taste that needs to be studied through other research to reveal the chemical components or compounds responsible for this taste.This information is important because it will be a solution and a reference for improving the quality of Seko coffee to become a specialty coffee.

Conclusion
Applying coffee bean processing methods according to specialist standards can improve the quality of coffee physically and in falvor.the physical quality of seko coffee beans using the standard processing method (ss) based on sni 01-2907-2008 meets quality requirements i with a defect value of 6.1, while traditional processing applied by farmers (ns) is classified as quality 5 with a defect value of 145.5.
The flavor profile of Seko Arabica coffee at an altitude of 1,400 m above sea level with standard processing (SS) has a cup test score of 85.38 with flavor specifications: brown sugar, caramelly and flowery, while traditional processing (NS) has a cup test result of 83.75 with flavor specifications; caramely, herbal, and spicy.
Seko Arabica coffee which is processed with standard treatment (SS), has the potential to develop into a specialty coffee because it has a taste score of ≥ 80.00 (83.75-85.38)with a defect value of ˂ 8, and meets the requirements as specialty coffee in the "category" Premium Grade" as defined by the Specialty Coffee Association of America (SCAA).

9 Figure 3 .
Figure 3. Flavor profile of Seko Arabica coffee beans and Enrekang specialty coffee

Table 1 .
Physical quality of Seko Arabica coffee beans and comparative Enrekang coffee beans based on SNI 01-2907-2008.