© The Authors, 2026, Published by the Universidad del Zulia*Corresponding author: mcampo@utmachala.edu.ec
Keywords:
Phytochemical analysis
Coee
Extraction methods
Nutraceutical potential
Agro-industrial by-product.
Chemical composition and antioxidant activity of the silverskin of three varieties of Coffea arabica L.
Composición química y actividad antioxidante de la película plateada de tres variedades de Coea arabica L.
Composição química e atividade antioxidante da pele prateada de três variedades de Coea arabica L.
Ingrid Márquez Hernández
Mercedes Campo Fernández*
Arantxa Ainoa Bustamante Quinde
Ronald Steeven Echeverría Loayza
Osmany Cuesta Rubio
Nubia Lisbeth Matute Castro
Rev. Fac. Agron. (LUZ). 2026, 43(3): e264334
ISSN 2477-9407
DOI: https://doi.org/10.47280/RevFacAgron(LUZ).v43.n3.II
Food technology
Associate editor: Dra. Gretty R. Ettiene Rojas
University of Zulia, Faculty of Agronomy
Bolivarian Republic of Venezuela.
Universidad Técnica de Machala (UTMACH). Ecuador.
Received: 03-04-2026
Accepted: 03-06-2026
Published: 15-06-2026
Abstract
The silverskin (SS) of Coea arabica L., a byproduct of coee
processing, represents a potential source of bioactive compounds
with nutraceutical properties. The chemical composition (residual
moisture, ash, fats, proteins, and minerals) and antioxidant
capacity of the SS from three varieties of C. arabica (Acauã
[AW], Sarchimor Rojo [CR], and Catucaí Amarillo [CA]) from
the province of El Oro, Ecuador, were evaluated. The extraction of
secondary metabolites (total phenols and caeine) was performed
for 60 min using ultrasound (US: 30 °C, 40 Hz) and dynamic
digestion (D: 60 °C, 60 rpm), employing an ethanol:water mixture
of (70:30 % v/v) and a plant material:solvent ratio of 20:80 % w/v.
Total phenols were quantied using the Folin-Ciocalteu method,
and caeine analysis was performed through high-performance
liquid chromatography (HPLC) with DAD detection. The evaluated
samples met the residual moisture (RM) and total ash content
requirements according to the NTE INEN standards, also exhibiting
low percentages of fat and protein. The CR variety stood out with
44.8 mg.g⁻¹ of K and 24.9 mg.g⁻¹ of N. Method D extracted the
highest amount of phenolic compounds, with CR recording the
highest content at 85.0 mg GAE.g⁻¹ of dry extract (DE), which
positively correlated with a higher Trolox equivalent antioxidant
capacity (DPPH: 108.61 mg TEAC.g⁻¹ DE; FRAP: 122.96 mg
TEAC.g⁻¹ DE). In contrast, caeine levels were higher for the AW
variety extracted by US (128.44 mg.g⁻¹ DE), being statistically
dierent from the rest. The three varieties meet regulatory standards
and demonstrate that SS is a raw material of great interest to the
food and pharmaceutical industries.
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
Rev. Fac. Agron. (LUZ). 2026, 43(3): e264334 July-September ISSN 2477-9409.
2-6 |
Resumen
La película plateada (PP) de Coea arabica L., subproducto del
procesamiento del café, representa una fuente potencial de compuestos
bioactivos con propiedades nutracéuticas. Se evaluó la composición
química (humedad relativa, cenizas, grasas, proteínas y minerales) y
la capacidad antioxidante de la PP de tres variedades de C. arabica
(Acauã (AW), Sarchimor rojo (CR) y Catucaí amarillo (CA)), de
la provincia de El Oro, Ecuador. La extracción de los metabolitos
secundarios (fenoles totales y cafeína) se realizó durante 60 min
mediante ultrasonido (US: 30 °C, 40 Hz) y digestión dinámica (D: 60
°C, 60 rpm), usando etanol:agua (70:30 % v/v) y una relación materia
vegetal:solvente de 20:80 % m/v. La cuanticación de fenoles totales
se realizó empleando el método de Folin-Ciocalteu y el análisis de
cafeína mediante cromatografía líquida de alta eciencia (CLAE) con
detección DAD. Las muestras evaluadas cumplieron con el contenido
de humedad residual (Hr) y cenizas totales según las normas NTE
INEN, presentando, además, bajos porcentajes de grasa y proteínas.
La variedad CR destacó con 44,8 mg.g
-1
de K y 24,9 mg.g
-1
de N.
El método D extrajo la mayor cantidad de compuestos fenólicos,
siendo CR la que registró el mayor contenido con 85,0 mg EAG.g
-1
de extracto seco (ES), lo que correlacionó positivamente con una
mayor capacidad antioxidante equivalente a trolox (DPPH: 108,61
mg TEAC.g
-1
ES; FRAP: 122,96 mg TEAC.g
-1
ES). En contraste, los
niveles de cafeína, fueron superiores para la variedad AW extraída por
US (128,44 mg.g
-1
ES), siendo estadísticamente diferentes al resto.
Las tres variedades cumplen los parámetros normativos y demuestran
que la PP es una materia prima de gran interés para las industrias
alimentaria y farmacéutica.
Palabras clave: análisis toquímico, café, métodos de extracción,
potencial nutracéutico, subproducto agroindustrial.
Resumo
A película prateada (PP) de Coea arabica L., um subproduto do
processamento do café, representa uma fonte potencial de compostos
bioativos com propriedades nutracêuticas. Avaliou-se a composição
química (umidade residual, cinzas, gorduras, proteínas e minerais)
e a capacidade antioxidante da PP de três variedades de C. arabica
(Acauã [AW], Sarchimor Rojo [CR] e Catucaí Amarillo [CA]), da
província de El Oro, Equador. A extração dos metabólitos secundários
(fenóis totais e cafeína) foi realizada durante 60 min mediante
ultrassom (US: 30 °C, 40 Hz) e digestão dinâmica (D: 60 °C, 60
rpm), utilizando etanol:água (70:30 % v/v) e uma proporção matéria
vegetal:solvente de 20:80 % m/v. A quanticação de fenóis totais
foi realizada empregando o método de Folin-Ciocalteu e a análise
de cafeína por cromatograa líquida de alta eciência (CLAE) com
detecção DAD. As amostras avaliadas cumpriram com o teor de
umidade residual (Ur) e cinzas totais segundo as normas NTE INEN
pertinentes, apresentando, além disso, baixos percentuais de gordura
e proteína. A variedade CR destacou-se com 44,8 mg.g⁻¹ de K e 24,9
mg.g⁻¹ de N. O método D extraiu a maior quantidade de compostos
fenólicos, sendo a CR a que registrou o maior teor com 85,0 mg EAG.
g⁻¹ de extrato seco (ES), o que correlacionou-se positivamente com
uma maior capacidade antioxidante equivalente a trolox (DPPH:
108,61 mg TEAC.g⁻¹ ES; FRAP: 122,96 mg TEAC.g⁻¹ ES). Em
contrapartida, os níveis de cafeína foram superiores para a variedade
AW extraída por US (128,44 mg.g⁻¹ ES), sendo estatisticamente
diferentes das demais. As três variedades cumprem os parâmetros
normativos e demonstram que a PP é uma matéria-prima de grande
interesse para as indústrias alimentícia e farmacêutica.
Palavras-chave: análise toquímica, café, métodos de extração,
potencial nutracêutico, subproduto agroindustrial.
Introduction
Coee is one of the most globally consumed beverages, with
Ecuador being the fourth regional exporter of Coea arabica L.
(Ministry of Agriculture and Livestock [MAG], 2021). Large volumes
of by-products are generated during its processing, constituting
nearly 90 % of the fruit, with silverskin (SS) standing out due to its
inadequate management and possible environmental impact (Hayes
et al., 2023; Santanatoglia et al., 2024). The SS contains more than 40
bioactive metabolites, including phenolic compounds and alkaloids
such as caeine, which makes it particularly interesting for its
antioxidant potential with possible use in nutritional or pharmaceutical
therapies (Hayes et al., 2023; Nolasco et al., 2022; Barreto et al.,
2022; Prakash and Doan, 2022; Santanatoglia et al., 2024). Since
phytochemical research on landraces is limited, this research aims
to analyze the chemical composition (residual moisture, ash, fats,
proteins, and minerals) and antioxidant activity in terms of total
phenols and caeine of extracts obtained from the SS of C. arabica L.
var. CR, CA, and AW, using chromatographic and spectrophotometric
techniques, which scientically validate their possible use in health.
Materials and methods
Study area
The SS of the three varieties of
C. arabica (AW, CR, CA)
was obtained in April 2024 from the “Don Salvador Café” coee
plantation, located in Las Lajas, El Oro, Ecuador (coordinates 03°47’
S, 80°04’ W; approximate altitude of 600 m.a.s.l.). The horticultural
management of the plantation consisted of rainfed irrigation, soil
fertilization, maintenance pruning, and integrated pest and disease
control.
Sample preparation
The samples were processed in the Phytochemistry laboratory
of the Technical University of Machala, Ecuador, in 2025. From
15 kg of ripe fruits processed by the wet method, the SS sample of
the three varieties (AW, CR, CA) was obtained. Drying was carried
out at 45 °C in an oven (MEMMERT UF 55, Germany) with 100%
forced-air circulation for approximately 24 h. It was then ground in
a mill (BIOBASE Disintegrator HSD-400, 25,000 rpm, China) and
passed through an 850 μm mesh sieve (HUMBOLDT). All samples
were packed in airtight plastic bags at room temperature (25 °C) and
stored in a desiccator until the respective analyses were carried out
(for approximately two months).
Proximate analysis
The proximate composition included the determination of
residual moisture (RM), fats, proteins, ash, and minerals. The RM
was determined using a thermobalance with a halogen heating source
(OHAUS, MB90, United States), set to a temperature of 105 °C. The
determination of total ash was performed according to the method
established by the Association of Ocial Analytical Chemists
(AOAC 942.05, 1990). The percentage of total fats was determined
according to the methodology described by Pillco et al. (2021), with
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
Hernández et al. Rev. Fac. Agron. (LUZ). 2026, 43(3): e264334
3-6 |
some modications described by Campo Fernández et al. (2024).
Gravimetric determinations were performed in triplicate.
The analytical determination of proteins and minerals was carried
out at the facilities of the NEMALAB S.A. laboratory. Protein
content was quantied using the micro-Kjeldahl method, applying
the conversion factor of 6.25 for total nitrogen. On the other hand, the
quantication of minerals (expressed in mg.g
-1
of dry plant material)
was performed following a wet digestion process, using a mixture of
nitric acid and perchloric acid in a 2:1 ratio.
Preparation of extracts
The extracts were prepared using a hydroalcoholic mixture
of ethanol:water (70:30 % v/v), employing a ratio of plant
material:solvent (20:80 % m/v), using ultrasound (US) and dynamic
digestion (D) methods. Ultrasound-assisted solvent extraction was
performed in an ultrasound bath (ULTRASONIC BATH 5.7 L, Ficher
Scientic, United States) at 30 °C, 40 Hz for 1 h; while extraction by
digestion was performed in a thermostatic bath (BIOBASE, China)
with constant agitation (60 rpm) and 60 °C for the same time. Once
the extraction was complete, the extract was ltered with lter
paper (FILTRAK) and evaporated to dryness (DE) using a rotary
evaporator (HEIDOLPH LABOROTA 4001, ecient, Germany)
coupled to a cryostat (LAUDA/ALPHA RA-8) and a vacuum pump
(VACUUBRAND PC 600, Germany).
Quantication of total phenols using the Folin-Ciocalteu
method
The quantication of total phenols was performed according
to the methodology described by Campo-Fernández et al. (2021).
Absorbance was determined using a spectrophotometer (UV-Visible
SPECTROPHOTOMETER Evolution 201 Thermo Scientic, United
States) at 765 nm, employing plastic microcells (BRAND GMBH,
Germany). A calibration curve was performed with gallic acid 10
mg.mL
-1
(Sigma Aldrich) at concentrations between 0.1 and 0.9
mg.mL
-1
(y= 0.9457X + 0.0029), R
2
= 0.9916. Results were expressed
as mg of gallic acid equivalents per gram of DE (GAE.g
-1
DE).
Determination of caeine by high-performance liquid
chromatography (HPLC)
The caeine analysis was performed following the protocol of
Eticha and Bedassa (2020) with adaptations. Ten milligrams of DE
were dissolved in a hydroalcoholic mixture of HPLC-grade methanol
and ultrapure water (70:30 % v/v), and the solution was ltered
through a 0.2 µm membrane. For the analysis, a Thermo Scientic
Ultimate 3000 system, equipped with a quaternary pump, an
autosampler, and a diode array detector (DAD) (DIONEX Ultimate
3000 RS, United States) managed by Thermo Xcalibur software, was
employed. Chromatographic conditions included: a Hypersil GOLD
C18 column (150 mm × 4.6 mm x 5 μm). An isocratic elution was
performed using water (A) and methanol (B) at a ratio of 75:25 %
v/v; ow rate of 1 mL.min
-1
, 5 μL injection volume, and column
temperature controlled at 35 °C. The detection was made by UV-Vis
spectroscopy at 272 nm. A column cleaning stage was included after
each run. For caeine quantication, a calibration curve was prepared
with caeine (Supelco) within a range between 0.2 and 3.2 mg.mL
-1
(y= 6x10
6
X + 809901), R
2
= 0.9966. Results were expressed as mg of
caeine per gram of DE (mg.g
-1
DE)
Quantication of antioxidant capacity
Ferric ion reducing antioxidant power (FRAP)
It was carried out using the method of Benzie and Strain (1996),
applying the modications proposed by Campo-Fernández et al.
(2021). The calibration curve was elaborated with methanolic
solutions (SIGMA-ALDRICH absolute methanol for analysis) of
6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), at
concentrations of 0.027-0.227 mg.mL
-1
(y= 14.7533X + 0.0439), R
2
=
0.9962. The spectrophotometric reading was performed at 593 nm
in plastic microcells. The values obtained were expressed as Trolox
equivalent antioxidant capacity (TEAC) per gram of DE (TEAC.g
-1
).
2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging
capacity
The Brand-Williams method et al. (1995) was used with
some modications described by Campo-Fernández et al. (2021).
The calibration curve was elaborated with methanolic solutions
(SIGMA-ALDRICH absolute methanol for analysis) of Trolox, at
concentrations of 0.027-0.227 mg.mL
-1
(% Inh= 377.62X – 1.1825),
R
2
= 0.9941. The results obtained were expressed as Trolox equivalent
antioxidant capacity (TEAC) per gram of DE (TEAC.g
-1
).
Statistical analysis
A multifactorial analysis of variance (ANOVA) was performed
using the JAMOVI statistical software package, version 2.3.2,
considering the extraction method and the C. arabica variety as study
factors.
Results and discussion
Proximate analysis
Table 1 shows the proximate composition of SS, assays that help
determine the nutritional value, shelf life, and quality of the raw
material for its use in dierent industries (Ullah et al., 2023).
Table 1. Proximate chemical composition of samples from the
silverskin of C. arabica L. var. Acauã (AW), Sarchimor
Rojo (CR), Catucaí Amarillo (CA).
Parameters
(%)
AW
Mean ± S
CR
Mean ± S
CA
Mean ± S
Residual moisture
8.55 ± 0.29
a
7.72 ± 0.14
b
8.61 ± 0.30
a
Total ash
0.99 ± 0.09
a
0.65 ± 0.08
b
0.96 ± 0.05
a
Total fats
0.01 ± 0.00
a
0.06 ± 0.01
b
0.01 ± 0.01
a
Proteins
2.38 ± 0.03
a
2.49 ± 0.04
a
2.44 ± 0.02
a
Minerals (mg.g
-1
) AW CR CA
Nitrogen (N)
23.80 24.90 24.40
Phosphorus (P)
1.10 1.70 1.80
Potassium (K)
32.10 44.80 34.10
Calcium (Ca)
6.40 16.30 20.40
Magnesium (Mg)
1.60 3.20 2.30
Zinc (Zn)
0.03 0.03 0.02
Copper (Cu)
0.01 0.02 0.01
Iron (Fe)
0.23 0.22 0.17
Manganese (Mn)
0.08 0.09 0.09
Sodium (Na)
0.08 0.09 0.08
S = Standard deviation. Dierent letters within the same row indicate that there are statistically
signicant dierences (α=0.05).
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
Rev. Fac. Agron. (LUZ). 2026, 43(3): e264334 July-September ISSN 2477-9409.
4-6 |
As can be seen, while the RM of CR diers statistically
(p<0.05) from that obtained for AW and CA, they all comply with
the established standards (NTE INEN 2392, 2017). Although other
authors show values that dier from those obtained (Gottstein et al.,
2021; Martuscelli et al., 2021), all results guarantee the conservation
of dry plant material during storage (RM<12 %), preventing the
deterioration and proliferation of microorganisms.
In relation to the percentage of fat, low levels are present in the
three varieties, being even lower than what was reported by Bobková
et al. (2022) and Gottstein et al. (2021), which suggests that this
residue is not a relevant caloric source, since, in general, the value of
these nutrients is not usually high.
The determination of the protein percentage in the three varieties
evaluated showed similar results to each other, although with values
below the range of 16.3 % to 18.6 %, previously reported for cocoa
husks (Gottstein et al., 2021; Prandi et al., 2021). This discrepancy
could be attributed to extrinsic factors, such as sample storage time,
as well as to the thermal degradation of amino acids induced by the
Maillard reaction during the roasting process. However, the protein
levels detected support the use of this by-product in the formulation
of fortied foods or supplements, coinciding with the applications
suggested by Biondić Fučkar et al. (2023) and Hayes (2020).
The determination of total ash showed similar contents in the
AW and CA varieties, which were higher than the levels detected in
CR. The values obtained were within the acceptance range, as they
did not exceed the maximum limit of 5.0 % stipulated by the NTE
INEN 1123 standard (2016), and were relatively similar to the value
reported by Kristanto and Wijaya (2018), 1.3 %. However, it is worth
noting previous ndings with signicantly higher percentages (6.79
% and 8.15 %), which exceed current quality standards (Gottstein
et al., 2021; Martuscelli et al., 2021). Such discrepancies in the
inorganic residue obtained from the samples can be attributed to
the inuence of geographical origin, soil conditions of the crop,
and genotypic variations among the varieties analyzed. In addition,
the three varieties presented a mineral composition dominated by
potassium, nitrogen, calcium, and magnesium, with copper being
identied as the element with the lowest concentration. Regarding the
mineral prole shown in Table 1, it should be noted that the analysis
was proposed as an exploratory screening of the samples under study;
therefore, the data are presented descriptively. The reliability of these
data is based on the fact that the most relevant results were consistent
with previous studies (Gottstein et al., 2021; Martuscelli et al., 2021;
Bojórquez-Quintal et al., 2024), where the prevalence of potassium in
all the samples analyzed is conrmed.
Quantication of secondary metabolites and antioxidant
capacity
The quantication of secondary metabolites (total phenols and
caeine) and antioxidant capacity was determined by calibration
curves.
The results obtained for the quantication of secondary
metabolites are presented in Table 2.
Table 2. Quantication of secondary metabolites in the silverskin
of C. arabica var. Acauã (AW), Sarchimor Rojo (CR)
and Catucaí Amarillo (CA).
Sample
Total phenols (mg GAE.g
-1
DE
)
(Mean ± S)
Caeine (mg.g
-1
DE)
(Mean ± S)
US D US D
AW
58.88 ± 1.31
*c
73.70 ± 1.20
*b
128.44 ± 1.41
*a
111.10 ± 0.23
*b
CR
74.98 ± 2.12
*b
85.00 ± 2.04
*a
93.68 ± 0.20
*c
84.27 ± 0.31
*d
CA
34.31 ± 0.90
*e
38.82 ± 0.86
*d
74.13 ± 1.06
*e
65.07 ± 0.36
*f
US: Ultrasound extraction, D: Extraction by dynamic digestion. S: standard deviation. GAE:
Gallic acid equivalent. Dierent letters in the same variable (considering rows and columns)
indicate statistically signicant dierences according to Tukey's test (p < 0.05), *: There is
interaction between the sample variables and the extraction method.
Statistical analysis revealed that both the coee variety and the
extraction technique play a decisive role in the phytochemical prole of
SS. The analysis of variance (ANOVA) conrmed a highly signicant
interaction (p < 0.001) between the method and the variety for total
phenols and caeine. D signicantly guaranteed the extraction of
total phenols in all samples because the synergism between agitation
and temperature favored solubility and mass transfer from the plant
matrix (Martins de Sá et al., 2024). The CR variety stood out with the
highest concentration (85.00 mg GAE.g
-1
DE). It is relevant to note
that the values obtained for CR (85 mg GAE.g
-1
DE) are similar to
those reported by Franca et al. (2024) (78.3 mg GAE.g
-1
). It should be
noted that quantication based on the DE, rather than the crude liquid
extract, allowed for the concentration of the secondary metabolites
and eliminated the solvent dilution eect. On the other hand, the
extraction by US of the CR variety statistically equals the yield of the
AW variety treated with digestion.
On the contrary, ultrasound proved to be a superior method to
extract caeine, making the AW variety reach the highest value of
the study (128.44 mg.g
-1
DE). This dierence compared to dynamic
digestion is not attributed to a possible thermal degradation of the
alkaloid at 60 °C, since caeine is a highly thermostable compound
capable of maintaining its structure even under the severe temperatures
of the roasting process (Jung et al., 2021). The superiority of this
method is due to the high eciency of ultrasonic cavitation; the
micro-implosions generated caused a mechanical disruption in the
dense cellular matrix of SS, which facilitated a greater release of the
alkaloids into the solvent, compared to the mass transfer achieved by
the moderate agitation of dynamic digestion (Taweekayujan et al.,
2023)
The variations observed between varieties from the same
geographical area suggest that the biosynthesis of these compounds
is strongly regulated by specic genotypic and microenvironmental
factors (Bojórquez-Quintal et al., 2024).
Regarding antioxidant capacity, Table 3 shows the results obtained
using two dierent methods: DPPH and FRAP.
The biochemical trend coincided with the quantication of
phenolic compounds. In the DPPH assay, although the method-variety
interaction was not globally statistically signicant (p = 0.234), the
post hoc analysis conrmed that the CR variety was the best as a
hydrogen donor, without the extraction method (US vs D) generating
a signicant dierence for it. The FRAP assay showed that the CR
variety treated with dynamic digestion also registered the highest
reducing power (122.96 mg.g
-1
DE), statistically dierentiating itself
from the rest of the treatments.
In general, the evaluation of antioxidant capacity revealed a
marked superiority of the results obtained compared to previous
reports based on crude drug (Machado et al., 2023), which could
be attributed in the rst instance to the concentration of analytes in
the dry extract (DE) used in this research. The discrepancies with
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
Hernández et al. Rev. Fac. Agron. (LUZ). 2026, 43(3): e264334
5-6 |
Table 3. Antioxidant capacity in the silverskin of C. arabica L. var.
Acauã (AW), Sarchimor Rojo (CR) and Catucaí Amarillo
(CA).
Sample
TEAC-DPPH (mg.g
-1
DE)
(Mean ± S)
TEAC-FRAP (mg.g
-1
DE)
(Mean ± S)
US D US D
AW
81.25 ± 2.15
c
91.79 ± 0.87
b
58.34 ± 0.68
*d
89.61 ± 2.76
*c
CR
103.02 ± 5.16
a
108.61 ± 2.62
a
104.23 ± 0.09
*b
122.96 ± 1.39
*a
CA
27.33 ± 0.22
d
33.58 ± 0.68
d
35.72 ± 0.65
*f
39.79 ± 1.05
*e
US: Ultrasound extraction, D: Extraction by dynamic digestion. S: standard deviation. TEAC-
DPPH: Trolox equivalent antioxidant capacity, using the DPPH free radical. TEAC-FRAP:
Trolox equivalent antioxidant capacity, determined by ferric ion reducing antioxidant power.
*: There is interaction between the sample variables and the extraction method. Dierent
letters in the same variable (considering rows and columns) indicate statistically signicant
dierences according to Tukey’s test (p < 0.05).
ideal characteristics for safe preservation and an outstanding
mineral contribution in potassium and nitrogen. When evaluating
the extraction methods, it was found that D extraction favored the
obtaining of phenolic compounds, while US maximized caeine
recovery. Specically, the CR variety stood out as the most promising
option due to its concentration of polyphenols, which justied its
superiority in relation to antioxidant capacity, leaving caeine without
an active role in this redox mechanism; however, if the extraction of
this alkaloid is prioritized, the AW variety was positioned as the best
source.
These ndings conrmed that this coee by-product transcends its
status as waste, representing a sustainable and valuable raw material
for the development of new functional foods and therapies aimed at
human health.
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Conclusions
The analysis of the SS of the AW, CR, and CA varieties revealed
a valuable chemical and antioxidant prole that validates its
nutraceutical use. Initially, its proximate composition demonstrated
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