**3.1 Quantitative descriptive analysis of various kinds of coffee brewed**

A panel of 10 assessors was selected to evaluate 8 aroma attributes and 5 taste attributes of coffee beans. The aroma attributes tested are earthy, smoky, chocolate, caramel, nutty, rancid, herbal and woody. While the taste attributes tested are acidity, bitter, sweet, salt, and sour.

The strength of the correlation between the characteristic expression term and the taste (preference) that had a significant difference was calculated using the correlation function in Excel (**Table 1**).

From **Table 1**, when n = 9, from the correlation coefficient test table, it is judged that there is a significant positive correlation when r = 0.666 or more at 5% risk rate. So, it is shown from **Table 1** data of coefficient correlation result that all attributes have no correlation with the liking, because all the number of r is 0.05 from the table (n = 9 and r total sample = 0.666) which is bigger than the number of the correlation result (see **Figure 1**).

**Figures 1** and **2** show the smell of sample coffee from Indonesia (sample difference treatment, fermentation) and Japan, so is the result is gaining attribute earthy, smoky, chocolate-like, caramel-like, nutty, herbal-like, and woody, like all sample are similar because the number from the result analysis, statistical (ANOVA), is low when compared to the number from q table, when total sample is 9 (q9 72 = 4.7937), and except the attribute rancid, only for sample A, C, G, I, and F is similar, then sample B, E, D, and H is not similar because the number from result ANOVA is bigger than number from q table.

**Figure 3** shown is the taste of coffee sample from Indonesia (sample difference treatment, fermentation) and Japan, so is the result attribute bitterness, sweetness, saltiness, like all samples are similar because the number from result analysis, statistical (ANOVA), is low compared to the number from q table, when total sample is 9 (q9 72 = 4.7937), and except the attribute acidity for the sample D, I, and F are not similar because the number is bigger than number from table q, and then attribute sourness for the sample I, D, and F is same as the attribute acidity is not similar.


#### **Table 1.**

*Correlation coefficient of each characteristic expression term.*

**Figure 2.**

*Sensory analysis of coffee based on earthy, smokey, chocolate-like, caramel like, nutty, rancid, herbal-like, and woody-like odor flavor attributes.*

*Aroma Profile of Arabica Coffee Based on Ohmic Fermentation DOI: http://dx.doi.org/10.5772/intechopen.98638*

**Figure 4(A)** shows the results of sensory taste with QDA described in the sample A with smokey attribute panelist, giving the highest value in the sample compared with a sample of coffee from Japan than Indonesia. Attribute woody and liking panelist provide similar valuation between the two samples of the coffee, but the attribute rancid panelist provides high value, attribute nutty, caramel, and chocolate panelist, giving nonsimilarity to the second sample.

Based on the results, it can be seen that coffee with sample code A (EH2T30) has the highest value on the sour taste attribute, while coffee with code I (Japan) has the highest value on the sweet taste attribute. This shows that coffee A and coffee I have no similarities, and in general the panelists prefer coffee with sample code I.

**Figure 4(A)** and **(B)** can be explained that the sensory panelists' smell gives the highest value apart from all attributes except chocolate, caramel, and nutty, but at taste, sensory panelists provide the highest value of the sample A except attribute liking.

Based on the sensory analysis of the aroma of coffee beans, it shows that the woody and herbal aroma attributes in coffee sample I and B have similarities, but the smoke and rancid attributes in sample B have a higher value than coffee sample I. The taste attributes in both coffee samples show that sample B coffee has higher acidity and sour attributes than sample I coffee. There are similarities in the value of the sweet attribute in coffee I and coffee B.

#### **Figure 3.**

*Sensory analysis of coffee based on acidity, bitterness, sweetness, saltiness, sourness, and liking flavor attributes.*

**Figure 4.**

*(A) Result of sensory aroma sample a (EH2T30) with coffee from Japan (I) (JH0T0), and (B) result of sensory tastes sample a (EH2T30) with coffee from Japan (I).*

**Figure 5(A)** showed the sample coffee B (EH18T35) than I result of QDA and sensory test is nonsimilar for the attribute smoky, rancid, and herbal, because the number of attributes is bigger than sample B (EH18T35), and the attribute that is similar is the nutty, caramel-like, and chocolate-like. And **Figure 5(B)** showed the sample B (EH18T35) and I being nonsimilar for attributes acidity, sourness, and saltiness.

**Figure 6(A)** showed the sample coffee B (EH18T30) than I result analysis for attribute sweetness and liking is similar, and all attributes for a sample coffee B (EH18T30) number is getting bigger than the sample I for the sensory tastes.

**Figure 7(A)** showed that the results of QDA and sensory aroma of sample coffee D (EH2T35) and I such as smokey and rancid is nonsimilar. High scores aroma smoke and rancid were also found in sample with I (Japan coffee).

The lowest aroma scores were found in sample D (EH2T35) as attributes being earthy, herbal, and rancid. **Figure 7(B)** showed the sensory tastes of coffee sample D (EH2T35) and I were found to be similar except the bitterness being lowest taste flavor.

**Figure 8(A)** from QDA of each attribute showed nonsimilar (significant difference) in smokey, rancid, herbal, nutty, and caramel-like when smelled directly. And **Figure 8** showed also non similar in acidity, sourness when tastes directly. Sample E (MH2T35) showed the lowest value in earthy, rancid, smoky, herbal and liking. No significant difference was noted by 10 panelists.

#### **Figure 5.**

*(A) Result of sensory aroma sample B (EH18T35) with coffee from Japan (I), and(B) result of sensory tastes sample B (EH18T35) with coffee from Japan (I).*

*Aroma Profile of Arabica Coffee Based on Ohmic Fermentation DOI: http://dx.doi.org/10.5772/intechopen.98638*

#### **Figure 6.**

*(A) Result of sensory aroma sample C (EH18T30) with coffee from Japan (JH0T0), and (B) result of sensory tastes sample C (EH18T30) with coffee from Japan (I).*

#### **Figure 7.**

*(A) Result of sensory aroma sample D (EH2T35) with coffee from Japan (I), and (B) result of sensory tastes sample D (EH2T35) with coffee from Japan (I).*

#### **Figure 8.**

*(A) Result of sensory aroma sample E (MH2T35) with coffee from Japan (I), and (B) result of sensory tastes sample E (MH2T35) with coffee from Japan (I).*

When comparing to type sensory analysis of coffee beverage, sample coffee E (MH2T35) has the lowest value than sample I (Japan), and with the other sensory tastes, the sample I (Japan) has higher preference and a higher liking attribute.

**Figure 9(A)**, shows that all aroma attributes except the smoke attribute in sample F have similarities with the aroma attribute of sample I. The smoke attribute in sample I has a higher value than coffee sample F. **Figure 9(B)** showed all attributes of samples F and I are similar. When comparing the two types of sample coffees' smell and tastes, sample coffee F has higher value than sample I.

**Figure 10(A)**, from QDA of each attribute, showed a nonsimilarity (significant difference) in smokey, rancid, herbal, nutty, and caramel-like when smelled directly. And **Figure 11** showed also nonsimilarity in acidity and sourness when tasted directly. Sample G showed the lowest value in earthy, rancid, smoky, herbal, and liking. No significant difference was noted by 10 panelists.

When comparing to type sensory analysis of coffee smell, sample coffee G has the lowest value than sample I, and with the other sensory tastes, sample G has

#### **Figure 9.**

*(A) Result of sensory aroma sample F (MH18T40) with coffee from Japan (I), and (B) result of sensory tastes sample F (MH18T35) with coffee from Japan (I).*

#### **Figure 10.**

*(A) Result of sensory aroma sample G (MH2T30) with coffee from Japan (I), and (B) result of sensory tastes sample G (MH2T30) with coffee from Japan (I).*

#### *Aroma Profile of Arabica Coffee Based on Ohmic Fermentation DOI: http://dx.doi.org/10.5772/intechopen.98638*

higher value preference for the attributes acidity and sourness than the sample I which has very lowest value due to a higher liking attribute.

**Figure 11(A)**, from the results of QDA of each attribute, showed a nonsimilarity (significant difference) in smokey, rancid, and chocolate-like smell directly. Attribute smoke and rancid from the sample I showed higher value than sample H. **Figure 11(B)** also shows the non-similarity in the acidity, saltiness, and sourness attributes between sample H and sample I. These three attributes have higher values in sample H compared to sample I.

Based on **Figure 12**, it can be explained that the earthy aroma of coffee is the main attribute; the greatest compound that provides the earthy aroma is pyrazine; from nine samples tested, the largest sample from Japan coffee that has aroma earthy is identified. Furthermore, sample G (MH2T30) is a sample of the unidentified compound pyrazine, but the results of sensory taste panelists can identify the smell.

Based on **Figure 13**, it can be seen that the 2,2-Furanmethanol compound has the highest peak area of GC-MS result for the smoky attribute aroma. Based on the results of sensory taste, the panelist also found that smoky attribute is similar for all sample coffees, and gives no significant sample.

#### **Figure 11.**

*(A) Result of sensory aroma sample H(MH6T35) with coffee from Japan (I), (B) Result of sensory taste sample H(MH6T35) with coffee from Japan (I).*

#### **Figure 12.**

*Compound volatile aroma Arabica coffee by GC-MS compared with sensory taste attribute earthy.*

Based on **Figure 14**, volatile compound identified from chocolate's aroma has five largest compounds, and the largest is compound pyrazine, 2,6-dimethyl in EH2T35 sample. Pyrazine-1,4-diazine compound is a compound which is identified

#### **Figure 13.**

*Compound volatile aroma Arabica coffee bye GC-MS compare with sensory taste attribute smoky.*

#### **Figure 14.**

*Compound volatile aroma Arabica coffee by GC-MS compared with sensory taste attribute chocolate.*

#### **Figure 15.**

*Compound volatile aroma Arabica coffee by GC-MS compared with sensory taste attribute caramel.*

#### *Aroma Profile of Arabica Coffee Based on Ohmic Fermentation DOI: http://dx.doi.org/10.5772/intechopen.98638*

only in the sample EH18T35, while the other sample was not identified. Sample G (MH6T35) is a compound sample that can identify only one type of its volatile compound which is pyrazine, 2,5-dimethyl.

Based on **Figure 15**, it can be explained that the volatile compound identified by GC-MS related to the results of sensory taste attributes aroma are 2-furancarboxaldehyde, 2(3H)-Furanone, Maltol, and 2,5-anhydro-1,6-dideoxyhexo. Volatile compound identified from the largest peak area is 2-Furancarboxaldehyde and is identified in sample A (EH2T30). Maltol compound is a compound which is identified in all kinds of samples of coffee with a peak area that is not too wide and not too small.

#### **Figure 16.**

*Compound volatile aroma Arabica coffee by GC-MS compared with sensory taste attribute nutty.*

**Figure 17.** *Results of PCA attribute.*

Attribute nutty coffee aroma in the studied sample identified by GC-MS can be seen in **Figure 16**. There are nine volatile compounds identified. The largest peak area of volatile compound identified is furfural; this compound is identified in samples F (MH2T35) with the area of the peak being 7.1846.

Based on the results of the sensory analysis in **Figure 17**, it can be seen that the panelists rated "like and have a correlation" on the smoky, woody, and rancid attributes. For the acidity attribute, the panelists assessed "dislike but have a correlation". In addition, the panelists assessed "dislike and no correlation" on the nutty, caramel-like, sweet, earthy, and herbal attributes.
