CELEBES Agricultural 6.
: 56 - 65 February .
Research Article Effect of Roasting Time on Total Phenolic Content and Antioxidant Activity of Cocoa Bean Shells Pengaruh Waktu Sangrai terhadap Total Fenol dan Aktivitas Antioksidan Kulit Biji Kakao Nadirah B Andi Pallawa1*.
Miming Berlian Hi.
B Salam1 .
Laras Ayu1 Study Program of AgroProduct Processing Technology.
Politeknik Palu.
Jl.
Sinar Kemuning I No.
Palu.
Central Sulawesi 94119.
Indonesia Abstract: Cocoa bean shells are a by-product of cocoa processing that contain bioactive compounds, particularly phenolics, with potential antioxidant activity.
However, information on the effect of roasting time on the total phenolic content and antioxidant activity of fermented cocoa bean shells remains limited.
Therefore, this study evaluated the effect of roasting time on the total phenolic content and antioxidant activity of fermented cocoa bean shells derived from Forastero cocoa beans (BR 25 variet.
from Bolang Village.
Enrekang Regency.
A laboratory experiment was conducted using a drum roaster with a charge temperature of 135AC and roasting times of 10, 14, 18, and 22 min.
Roasting time significantly affected total phenolic content and antioxidant activity.
Roasting for 14 min produced the highest mean total phenolic content .
1425 mg GAE/g extrac.
and the lowest IC50 value .
69 pp.
, although these results were not significantly different from those at 18 min.
In contrast, the 10 and 22 min treatments showed lower total phenolic content and weaker antioxidant activity.
These findings suggest that moderate roasting durations, particularly 14Ae18 min, were more favorable for maintaining the bioactive properties of cocoa bean shells.
Keywords: Antioxidant Activity.
Cocoa Bean Shells.
IC50.
Phenolic Compounds.
Roasting Time *email:
nadirahbap@gmail.
Received: July, 2025 Accepted: April, 2026 Published: April, 2026 p-ISSN: 2723-7974 e-ISSN: 2723-7966 doi: 10.
52045/jca.
Website:
https://ojs.
id/index.
php/faperta Abstrak: Kulit biji kakao merupakan produk samping pengolahan kakao yang mengandung senyawa bioaktif, terutama fenolik, dan berpotensi sebagai sumber antioksidan alami.
Namun, informasi mengenai pengaruh waktu penyangraian terhadap kandungan total fenol dan aktivitas antioksidan pada kulit biji kakao fermentasi masih terbatas.
Oleh karena itu, penelitian ini bertujuan untuk mengevaluasi pengaruh waktu penyangraian terhadap kandungan total fenol dan aktivitas antioksidan kulit biji kakao fermentasi yang berasal dari biji kakao Forastero varietas BR 25 dari Desa Bolang.
Kabupaten Enrekang.
Penelitian dilakukan secara eksperimen laboratorium menggunakan drum roaster dengan charge temperature 135AC dan waktu penyangraian 10, 14, 18, dan 22 menit.
Waktu penyangraian berpengaruh nyata terhadap kandungan total fenol dan aktivitas antioksidan.
Penyangraian selama 14 menit menghasilkan rerata kandungan total fenol tertinggi .
,1425 mg GAE/g ekstra.
dan nilai IC50 terendah .
,69 pp.
, meskipun hasil tersebut tidak berbeda nyata dengan penyangraian selama 18 menit.
Sebaliknya, perlakuan 10 dan 22 menit menunjukkan kandungan total fenol yang lebih rendah dan aktivitas antioksidan yang lebih lemah.
Temuan ini menunjukkan bahwa durasi penyangraian sedang, khususnya 14Ae18 menit, lebih baik dalam mempertahankan sifat bioaktif kulit biji kakao.
Kata kunci: Aktivitas antioksidan.
IC50.
Kandungan fenolik.
Kulit biji kakao.
Waktu Citation:
Pallawa NBA.
Salam MBHB.
Ayu L.
Effect of Roasting Time on Total Phenolic Content and Antioxidant Activity of Cocoa Bean Shells.
CELEBES Agricultural.
: 56-65.
doi: 10.
52045/jca.
CELEBES Agricultural Vol.
6 No.
February .
INTRODUCTION Cocoa bean shells are a promising source of bioactive compounds, particularly phenolic compounds and antioxidants, with potential for food and health-related applications.
They are also generated in large quantities as a by-product of chocolate processing, creating opportunities for their utilization as value-added products (Lembong et al.
, 2021.
Barbosa-Pereira et al.
, 2021.
Synchez et al.
, 2.
However, their functional potential may be influenced by cocoa processing steps, particularly fermentation and roasting, which can alter their phenolic content and antioxidant-related bioactive composition (Agustriana et al.
, 2023.
Lembong et al.
, 2.
Roasting induces chemical reactions that may modify phenolic compounds and antioxidant activity in cocoa-derived materials.
Previous studies have shown that variations in roasting temperature and time can influence bioactive compounds and antioxidant capacity.
Moderate roasting may enhance the extractability of phenolic compounds and antioxidant activity, whereas excessive roasting may reduce them because of the thermal degradation of heat-sensitive Cortez et al.
found that roasting was one of the postharvest stages that most strongly affected phenolic compounds in cocoa, particularly epicatechin, catechin, gallic acid, and caffeic acid.
Similar trends have been reported in other roasted plant materials, where intermediate roasting conditions preserved or enhanced bioactive compounds and antioxidant properties, while more intense roasting caused significant losses (Shawky et al.
, 2024.
Liu et al.
Spychaj et al.
, 2.
These findings suggest that roasting conditions play an important role in determining the functional quality of cocoa-derived materials.
However, only a limited number of studies have specifically addressed polyphenol content and antioxidant activity in cocoa bean shells after Although Pallawa et al.
examined roasting time, the focus was on cocoa nibs rather than cocoa bean shells.
Therefore, the effect of roasting time on the total phenolic content and antioxidant activity of fermented cocoa bean shells remains unclear.
This study aimed to determine how different roasting times influence these parameters to identify roasting conditions that may preserve or enhance the functional value of cocoa bean shells and support their potential application in value-added food products.
MATERIALS AND METHODS
Equipment and Materials The equipment used in this study comprised a drum roaster with a 1 kg capacity per batch.
It is a cylindrical, horizontally oriented device that is rotated manually and equipped with a digital thermometer to monitor the drum temperature.
Additional equipment comprised an analytical balance, 10 mL volumetric flasks, volumetric pipettes, a UV-Vis spectrophotometer, quartz or glass cuvettes, and test tubes.
The laboratory setup also required a vortex mixer, dark incubation chamber.
Erlenmeyer flasks, rotary vacuum evaporator, amber vials, micropipettes, measuring cylinders, stationery, and a laptop.
Pallawa et al.
Roasting Effect on Cocoa Shell Antioxidants CELEBES Agricultural Vol.
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The materials used in this study were cocoa beans (Forastero type.
BR 25 variet.
sourced from Bolang Village.
Enrekang Regency, and liquefied petroleum gas (LPG).
The chemicals and reagents used were 95% ethanol, 50 AAM DPPH solution, gallic acid .
, distilled water.
FolinCiocalteu reagent, and 20% anhydrous sodium carbonate (NacOCE).
Additional materials comprised zipper-lock plastic packaging.
Whatman filter paper, an aluminum foil roll, tissue paper, labels, and latex gloves.
Research Method A laboratory-based experimental method was used.
The study utilized a single-factor experimental design focused on the roasting duration.
Four treatments were implemented, each replicated four times, as described below.
T1 = 10 min T2 = 14 min T3 = 18 min T4 = 22 min Sample Preparation Cocoa beans were fermented for five days and then sun-dried under direct sunlight for five The dried beans were cleaned to remove foreign materials and sorted to eliminate damaged The beans were standardized in size to ensure uniformity Cocoa Bean Roasting The roasting process was adapted from Pallawa et al.
with minor modifications.
For each treatment, 250 g of cocoa beans was roasted in a drum roaster using a charge temperature of 135AC.
Roasting commenced upon bean insertion.
After the designated roasting period .
, 14, 18, or 22 mi.
, the cocoa shells were separated from the nibs and collected for subsequent analysis.
Analytical Procedures The following analyses were conducted to evaluate the total phenolic content and antioxidant activity of cocoa bean shells:
Preparation of Concentrated Extracts Cocoa shell extracts were prepared using a maceration technique adapted from Datu et al.
Roasted cocoa bean shells were ground and stored in airtight, dark containers.
Five grams of the powdered sample was macerated with 95% ethanol in a ratio of 1:5 for 24 h, repeated thrice.
The combined filtrates were filtered and concentrated using a rotary vacuum evaporator until a viscous extract was obtained for analysis.
Determination of Total Phenolic Content The total phenolic content of the cocoa shell extracts was determined using the FolinAe Ciocalteu method, as described by Datu et al.
and Hidayah et al.
A gallic acid Pallawa et al.
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calibration curve was prepared by dissolving 10 mg of gallic acid in 10 mL of a 1:1 ethanol-water The solution was diluted to obtain concentrations of 10, 20, 30, 40, 50 mg/L.
For calibration, 1 mL of each standard was mixed with 10 mL of distilled water and 1 mL of FolinAe Ciocalteu reagent.
After 8 min, 3 mL of 20% NacOCE solution was added.
The mixture stood for 2 Absorbance was then measured at 765 nm to construct the calibration curve.
For sample analysis, 10 mg of cocoa shell extract was dissolved in 10 mL of an ethanolwater mixture.
One milliliter of this solution was treated identically to the gallic acid standards.
The total phenolic content was calculated using the regression equation of the calibration curve.
The results were expressed as mg gallic acid equivalents per gram of extract .
g GAE/g extrac.
Determination of Antioxidant Activity Using the DPPH Method (IC.
Antioxidant activity was assessed using the DPPH radical scavenging method, as described by Datu et al.
and Hidayah et al.
A 10 mg sample of the extract was dissolved in 10 mL of ethanol to prepare a 1000 ppm stock solution.
Serial dilutions were prepared to reach concentrations of 20, 40, 60, 80, and 100 ppm.
Each 1 mL aliquot was mixed with 3 mL of 50 AAM DPPH solution, homogenized, and incubated in the dark for 30 min.
Absorbance was measured at 517 nm.
The percentage of inhibition was calculated, and the IC50 value was determined from the regression equation of the inhibition curve.
RESULTS AND DISCUSSION
Total Phenolic Content The results confirmed that cocoa bean shell extract, obtained using ethanol extraction, contained phenolic compounds with antioxidant activity, as determined by spectrophotometric Gallic Acid Standard Curve Figure 1.
Gallic acid standard curve for the determination of total phenolic content.
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The gallic acid standard curve showed a linear relationship between concentration and absorbance at 765 nm, with the regression equation y = 0.
01587x Oe 0.
02870 and a coefficient of determination (RA) of 0.
This result indicates excellent linearity of the calibration curve and confirms that it is suitable for determining the total phenolic content of cocoa bean shell extract.
The total phenolic content of the cocoa bean shell extract varied with roasting time.
Figure 2 shows how prolonged roasting alters the concentration of phenolic compounds.
Figure 2.
Total phenolic content of cocoa bean shell extract at different roasting times.
Bars with different letters indicate significant differences .
< 0.
according to TukeyAos honestly significant difference test.
Roasting for 14 min resulted in the highest total phenolic content, as measured by spectrophotometric analysis at 765 nm using the Folin-Ciocalteu method.
One-way analysis of variance revealed that roasting time significantly affected total phenolic content (F = 18.
819, p < TukeyAos honest significant difference test showed that the 14 min treatment was not significantly different from the 18 min treatment but differed significantly from the 10 min and 22 min treatments.
Likewise, the 10 and 22 min treatments were not significantly different from each other.
These findings demonstrate that roasting time significantly affects the total phenolic content of cocoa bean shell extract.
Previous studies have shown that thermal processing may temporarily increase phenolic content by releasing bound compounds from the plant matrix.
however, prolonged heating may reduce it due to oxidative and thermal degradation.
This pattern is consistent with the present results, in which the total phenolic content increased at 14 min, remained statistically similar at 18 min, and then declined at 22 min.
The increase in total phenolic content under moderate roasting may be associated with the improved extractability of phenolic compounds during heating.
Similar trends have been reported by Kataria et al.
in teff grains and by Calinoiu and Vodnar .
in wheat and oat bran, where thermal processing enhanced the release of phenolic compounds.
In cocoa bean shell.
Lembong et al.
also reported that roasting influenced polyphenol content and antioxidant activity, indicating that thermal treatment plays an important role in determining its functional properties.
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In contrast, the decrease in total phenolic content at longer roasting times may be attributed to the degradation of heat-sensitive phenolic compounds during extended heat exposure.
Prolonged heating can promote oxidation and structural degradation of phenolic compounds, thereby reducing their concentration in the extract.
This explanation is in line with Calinoiu and Vodnar .
, who reported that excessive thermal treatment increases the risk of phenolic Thus, the present study suggests that moderate roasting durations, particularly 14Ae18 min, are more favorable for maintaining total phenolic content than shorter or longer roasting times.
Although roasting for 14 min produced the highest mean total phenolic content, it was statistically similar to roasting for 18 min.
Antioxidant Activity The antioxidant activity of cocoa bean shell extract, expressed as IC50 values from the DPPH radical scavenging assay, varied significantly with roasting duration (Figure .
The IC50 values at 10, 14, 18, and 22 min were 133.
61 A 16.
42, 83.
69 A 10.
36, 105.
63 A 9.
75, and 140.
79 A 10.
ppm, respectively.
The lowest IC50 value was observed at 14 min, indicating the strongest antioxidant activity.
TukeyAos honestly significant difference (HSD) test revealed that the 14 min treatment did not differ significantly from the 18 min treatment, but both showed significantly lower IC50 values than the 10 and 22 min treatments.
In contrast, the 10 and 22 min treatments were not significantly different from each other.
These results indicate that roasting time significantly affected the antioxidant activity of cocoa bean shell extract, as reflected by the IC50 values.
Roasting for 14 min produced the lowest IC50 value, indicating the strongest antioxidant activity, although it was not significantly different from roasting for 18 min.
Previous studies have shown that moderate thermal treatment can enhance antioxidant activity by improving the release or extractability of phenolic and other bioactive compounds, whereas excessive heating may reduce antioxidant capacity because of thermal degradation and oxidative changes.
Similar trends were reported by Rodryguez-Solana et al.
, and Hatamian et al.
, who found that appropriate roasting conditions could enhance antioxidant-related properties in plant materials.
In the present study, the increase in IC50 after moderate roasting suggests a decline in antioxidant activity with prolonged heat exposure.
This may be attributed to the degradation of heat-sensitive antioxidant compounds during roasting.
Therefore, moderate roasting durations, particularly 14Ae18 min, appear to be more favorable for maintaining antioxidant activity than shorter or longer roasting times.
These insights suggest that optimizing thermal conditions can be an effective strategy for enhancing the antioxidant capacity of food products.
The current study strongly supports this finding, highlighting the importance of selecting ideal roasting parameters to maximize the health-promoting properties of cocoa-based ingredients.
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Figure 3.
Antioxidant activity of cocoa bean shell extract at different roasting times based on the DPPH Bars with different letters indicate significant differences at p < 0.
05 according to TukeyAos HSD test.
Correlation Between Total Phenolic Content and Antioxidant Activity Figure 4 shows a strong negative correlation between total phenolic content and IC50 values, with the regression equation y = -15.
42 and RA = 0.
As the phenolic content increased, the IC50 values decreased, indicating stronger antioxidant activity.
This result suggests that phenolic compounds play an important role in the antioxidant capacity of cocoa bean shell Figure 4.
Correlation between total phenolic content and IC50 values of cocoa bean shell extract at different roasting times.
These findings are in agreement with previous studies showing that roasting under appropriate conditions can enhance phenolic content and antioxidant activity, as reported for rapeseed oil by Siger et al.
, carob by Rodryguez-Solana et al.
, and chia seeds by Pallawa et al.
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Hatamian et al.
Such evidence underscores the importance of optimizing roasting conditions to maximize the antioxidant potential associated with phenolic compounds.
In the present study, antioxidant activity was strongly associated with total phenolic Roasting for 14 min produced the strongest antioxidant activity, although it was statistically similar to roasting for 18 min.
This finding suggests that phenolic compounds play an important role in the antioxidant capacity of cocoa bean shell extract.
However, because the IC50 values remained above 50 ppm, a higher extract concentration may still be required to achieve greater antioxidant effectiveness.
A major strength of this study is the use of a roasting method that closely resembles smallscale industrial practice, enhancing its practical relevance and potential applicability.
Nevertheless, the relatively high IC50 values may limit the extractAos effectiveness in certain Therefore, further studies involving alternative processing methods, extraction conditions, and larger-scale systems are warranted to confirm and extend these findings.
CONCLUSIONS
Roasting duration significantly affected the total phenolic content and antioxidant activity of fermented cocoa bean shells.
Moderate roasting durations .
Ae18 mi.
were more favorable than shorter or longer roasting times.
Roasting for 14 min produced the highest mean total phenolic content and the lowest IC50 value, although it was statistically similar to roasting for 18 These results suggest that controlled roasting may improve the functional potential of cocoa bean shells.
however, further optimization is required to enhance antioxidant effectiveness.
ACKNOWLEDGMENT
The authors gratefully acknowledge the Directorate of Research and Community Service (DRTPM) for providing research grant funding under the 2024 fiscal year scheme.
This support significantly aided the implementation of this study.
We thank the laboratory staff at Politeknik Palu for their technical assistance during the roasting process and for utilizing the provided We also appreciate Universitas Tadulako for providing access to laboratory facilities and support during spectrophotometric analysis.
Special thanks are due to the local cocoa farmers in Bolang Village.
Enrekang Regency, who supplied the fermented cocoa beans used in this The authors also thank their colleagues for contributing academic input and feedback on the manuscript draft.
REFERENCES