Use of avocado peel (Persea americana) in tea formulation: A functional product containing phenolic compounds with antioxidant activity

Abstract

The peels of avocados, like other fruit peels, are commonly discarded, not knowing their potential use. In order to reuse avocado peel, the chemical and mineral compositions, total phenolic and flavonoid contents as well as antioxidant activities have been investigated by DPPH (1,1-diphenyl-2-picrylhydrazyl) and FRAP(ferric-reducing antioxidant power) methods in in natura and dehydrated avocado peel. Dehydrated avocado-peel tea was manufactured and the antioxidant activity was evaluated, as well as their flavonoid and phenolic compound contents, and compared with other teas marketed. Avocado peel, especially dried avocado peel, contains major phenolic compounds (10,848.27 +/- 162.34 mg GAE kg(-1)) and flavonoids (1,360.34 +/- 188.65 mg EQ kg(-1)). The avocado-peel tea showed antioxidant activity by DPPH (1,954.24 +/- 87.92 e 2518.27 +/- 192.59 mg TE L-1) and phenolic and flavonoids contents highest than apple tea. The avocado-peel tea showed good antioxidant activity and had good acceptability by sensory analysis as a promising product.

Full text

A
cta Scientiarum
http://www.uem.br/acta
ISSN printed: 1806-2563
ISSN on-line: 1807-8664
Doi: 10.4025/actascitechnol.v38i1.27397
Acta Scientiarum. Technology Maringá, v. 38, n. 1, p. 23-29, Jan.-Mar., 2016
Use of avocado peel (Persea americana) in tea formulation: a
functional product containing phenolic compounds with
antioxidant activity
Eliza Mariane Rotta
1
, Damila Rodrigues de Morais
2
, Polyana Batoqui França Biondo
1
, Vanessa
Jorge dos Santos
1
, Makoto Matsushita
1
and Jesui Vergilio Visentainer
1*
1
Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
2
Departamento de
Química, Universidade Estadual de Campinas, 13083-872, Campinas, São Paulo, Brazil. *Author for correspondence. E-mail:
jvvisentainer@uem.br
ABSTRACT. The peels of avocados, like other fruit peels, are commonly discarded, not knowing their
potential use. In order to reuse avocado peel, the chemical and mineral compositions, total phenolic and
flavonoid contents as well as antioxidant activities have been investigated by DPPH (1,1-diphenyl-2-
picrylhydrazyl) and FRAP(ferric-reducing antioxidant power) methods in in natura and dehydrated avocado
peel. Dehydrated avocado-peel tea was manufactured and the antioxidant activity was evaluated, as well as
their flavonoid and phenolic compound contents, and compared with other teas marketed. Avocado peel,
especially dried avocado peel, contains major phenolic compounds (10,848.27 ± 162.34 mg GAE kg
-1
) and
flavonoids (1,360.34 ± 188.65 mg EQ kg
-1
). The avocado-peel tea showed antioxidant activity by DPPH
(1,954.24 ± 87.92 e 2518.27 ± 192.59 mg TE L
-1
) and phenolic and flavonoids contents highest than apple
tea. The avocado-peel tea showed good antioxidant activity and had good acceptability by sensory analysis
as a promising product.
Keywords: avocado, fruit peels, DPPH, FRAP, sensorial analysis, functional foods.
Uso da casca do abacate (Persea Americana)na formulação de chá: um produto funcional
contendo compostos fenólicos e atividade antioxidante
RESUMO. Cascas de frutas são comumente descartadas, assim como cascas de abacate, por
desconhecimento do seu potencial uso. A fim de reutilizar a casca de abacate, determinou-se a composição
química e de minerais, conteúdo de fenólicos totais e de flavonoides, bem como atividades antioxidantes
por ensaios de DPPH (1,1-difenil-2-picrilhidrazil) e FRAP (poder antioxidante por redução do ferro) nas
cascas in natura e desidratada. Formulou-se um chá com a casca de abacate, avaliou-se sua atividade
antioxidante, bem como conteúdo de fenólicos e flavonoides e comparou-se com chás comercializados.
Os resultados mostram que na casca de abacate desidratada contém compostos fenólicos (10.848,27 ±
162,34 mg EAG kg
-1
) e flavonoides (1.360,34 ± 188,65 mg EQ kg
-1
). O chá da casca de abacate desidratada
apresentou atividade antioxidante por DPPH (1954.24 ± 87.92 e 2518.27 ± 192.59 mg ET L
-1
) superior ao
chá de maçã, assim como maior conteúdo de fenólicos e flavonoides. O chá de casca de abacate apresentou
boa atividade antioxidante e boa aceitação por análise sensorial, mostrando ser um produto promissor.
Palavras-chave: abacate, casca de frutas, DPPH, FRAP, análise sensorial, alimento funcional.
Introduction
Avocado (Persea americana) fruit has great
nutritional importance as a source of carbohydrate,
protein, and fiber and the avocado contains essential
micronutrients for human consumption such as
vitamins, minerals, and polyphenols (Harborne &
Williams, 2000; Pennington & Fisher, 2009). The
consumption of 3-4 fruit portions per day is
recommended. The regular consumption of fruit
(Barbosa et al., 2005), has been associated with the
reduction of degenerative, cardiovascular (Ishida,
Schubert, & Sagar, 2001; Abdille, Singh,
Jayaprakasha, & Jena, 2005) and circulatory diseases
(Scharamm & German, 1998). These effects have
been attributed to the presence of phenolic
compounds such as flavonoids, especially in fruit
peels, which have antioxidant properties (Broiniz
et al., 2007).
There is a lack of knowledge about fruit and
vegetable nutrients, as well as their skins and stems,
generating waste in tons that could be used as food.
The same true for the avocado, because tons of this

24 Rotta et al.
Acta Scientiarum. Technology Maringá, v. 38, n. 1, p. 23-29, Jan.-Mar., 2016
fruit are discarded in trash in Brazil. The oil of an
avocado has medicinal properties (Lu et al., 2005)
and its peel contains significant amounts of minerals
(Gondin, Moura, & Dantas, 2005) in addition to
compounds that prevent lipid oxidation (Rodríguez-
Carpena, Morcuende, & Estévez, 2012). The leaves
and peels could also be consumed as medicinal food
(Marques, 2001).
Originating from China, tea is a very popular
drink that is widely consumed by many people
around the world and currently, tea is receiving
interest due to its beneficial health effects, which are
being investigated for having antioxidant activity,
mainly attributed to the high concentration of
polyphenols (phenolic acids, flavonoids, and
catechins) (Kodama, Gonçalves, Lajolo, &
Genovese, 2010; Nishiyama et al., 2010; Oliveira,
2012). By definition, teas are products made from
parts of plants (whole, fragmented, or ground)
obtained by appropriate technological processes,
each species is used exclusively in the preparation of
food beverages by infusion or decoction in drinking
water and may not have pharmacotherapeutic
purposes (Brasil, 1998).
With the aim to inform people about the
nutritional value of avocado peel and to reduce the
perishable nature of this waste by processing, the
present study examined the chemical and mineral
composition of avocado peel in natura (INAP) and in
dehydrated avocado peel (DAP) in order to provide
a low-cost food for a healthy diet. After drying, an
avocado-peel tea was developed and the chemical
composition and antioxidant capacity of the food
was studied, with the aim of identifying a way to
reuse this waste.
Material and methods
Chemical reagents
The reagents were 1,1-diphenyl-2-picrylhydrazyl
(DPPH), 6-hydroxy-2,5,7,8-tetramethyl chroman-
2-carboxylic acid (Trolox), 2,4,6-tris(2-pyridyl)-s-
triazine (TPTZ), quercetin and Folin-Ciocalteu
phenol reagent from Sigma-Aldrich (São Paulo,
Brazil). Ferrous sulfate heptahydrate, iron chloride
hexahydrate, aluminum chloride and gallic acid
purchased from Vetec and sodium carbonate
obtained from J. T. Baker were also used. All
solvents and chemicals were of analytical grade.
Sample preparation
Twelve kilograms of avocados (P. americana)
were acquired from trade Maringá, Paraná State,
which were grown in Brazil and harvested in 2012.
The fruits were washed with tap water, left for
10 min. in a solution of sodium hypochlorite. The
different parts of the fruit were separated by a
manual process into peel, pulp and seeds. A part of
the avocado peels were maintained in natura and the
others were chopped for drying in an oven at 60ºC
for 24 hours before analysis. Sachets of green tea,
apple tea, and mate tea were purchased from the
local market in Maringá, Paraná State, for
antioxidant activity analysis.
Proximal composition
The moisture, ash and crude protein levels were
determined according to Association of Official
Analytical Chemists (AOAC, 1998). The total lipids
were extracted using a mixture of methanol,
chloroform and water according to the method of
Bligh & Dyer (1959).
The amount of crude fiber was determined by
digestion, acid and basic, the according with Cecchi
(1999). The total carbohydrates were obtained by
difference calculation of other fractions [100 g –
total g (moisture, ash, protein, and lipids)] and
expressed as a Nifext (nitrogen-free extract) fraction.
The energy was calculated by multiplying the
amount (in kg) of protein, carbohydrate and lipid by
4.00, 3.75, and 9.00 kcal kg
-1
, respectively; the results
were expressed in kcal Food and Agriculture
Organization (FAO, 1985). The determination of
minerals was performed by atomic absorption
spectrometry, Analytik Jena novAA 300 (software
winAAS) instrument.
Extraction of antioxidants and tea preparation sachets
The in natura avocado peel (INAP) and
dehydrated avocado peel (DAP) extracts were
prepared according to Ribeiro et al. (2013) using
approximately 10 g of homogenized sample in
100 mL of methanol under magnetic stirring for 4h
in dark room. After filtration, the extracts were
concentrated under reduced pressure at 40ºC. The
dried peels were ground in an analytical mill, sieved
and forwarded to the preparation of sachet tea,
which contained 2.2 g of dried avocado peel inside a
filter paper. Some of the tea sachets were stored at
room temperature for 45 days for shelf life analysis.
At certain time periods (0 and 45 days after initial
storage) the tea was prepared by infusing the sachet
in 200 mL of hot water (96ºC) and leaving it to
stand for 5 min. After that, the tea was cooled to
25ºC for analysis.
Total phenolic content (TPC)
The TPCs of the avocado-peel extracts and
avocado-peel teas were analyzed using
Folin-Ciocalteu reagent (Shahidi & Naczk, 1995).

Avocado peel tea with antioxidant activity 25
Acta Scientiarum. Technology Maringá, v. 38, n. 1, p. 23-29, Jan.-Mar., 2016
The extract and tea solutions (250 μL) were mixed
with the Folin-Ciocalteu (250 μL) reagent (diluted
in distilled water, 1:1 v/v), saturated sodium
carbonate solution (500 μL), and distilled water
(4 mL). After 25 min. of incubation, the solution
was centrifuged for 10 min. at 3,000 rpm and the
absorbance was measured at 725 nm. The results
were expressed as milligrams of gallic acid
equivalents per kilogram avocado peel (mg GAE kg
-1
)
and for tea were expressed per liter (mg GAE L
-1
).
Flavonoids (FLAV)
For the analysis of flavonoids (Eberlin, 2009), a
solution (250 μL) of aluminum chloride 5% (v m
-1
) in
methanol was added to the extract or tea (500 μL) and
the volume was completed to 5 mL with methanol.
After 30 min., the absorbance was measured at 425 nm.
The results were expressed as milligrams of quercetin
equivalents per kilogram of avocado peel (mg QE kg
-1
)
and for the tea were expressed per liter (mg QE L
-1
).
Ferric-reducing antioxidant power (FRAP) assay
The FRAP assay was determined as described by
Benzie & Strain (1996), with modifications. The FRAP
reagent was prepared by mixing solutions of acetate
buffer (0.3 mol L
-1
, pH 3.6), TPTZ (10.0 mmol L
-1
),
and FeCl
3
(20.0 mmol L
-1
) in a 10:1:1 ratio. The extract
solutions or tea (100 μL), distilled water (300 μL), and
the FRAP reagent (3.0 mL) were combined in a tube
test; the mixture was kept in the dark for 30 min. at
37ºC. The absorbance was measured at 593 nm. The
results were expressed as micromoles of Fe
2
SO
4
.7H
2
O
per gram of sample (μmol g
-1
) and for the tea were
expressed per liter (μmol L
-1
).
DPPH
•
free-radical-scavenging assay
The DPPH
•
scavenging capacity was measured
using the method described by Brand-Williams,
Cuvelier, and Berset (1995) with modifications (Ma
et al., 2011). Briefly, the avocado-peel extract solutions
or teas (25 μL) were added to 6.25 × 10
-5
mol L
-1
methanolic
DPPH
•
solution (2 mL). The solution was
kept in the dark for 30 min. at room temperature, and
the absorbance was then measured at 517 nm. The
results were expressed as micromoles of Trolox
equivalents per gram of sample (μmol TE g
-1
) and for
the tea were expressed per liter (μmol TE L
-1
).
Microbiological assay and sensory analysis
The analysis of Salmonella spp. and thermo
tolerant coliforms in avocado-peel tea was
performed according to the Food and Drug
Administration (FDA, 1995) on 0 and 45 days after
the sachets were manufactured.
The DAP tea was prepared as described above
and after tea infusion, sugar was added at a ratio of
5.0 g per 200 mL of tea (Brasil, 2013) which was
maintained at a temperature between 60 and 70ºC in
vacuum flasks before it was served to a volunteer.
The sensory evaluation was performed at the
State University of Maringá in the Food laboratory,
with a staff of 100 non-trained volunteer panelists
and potential consumers of the avocado-peel tea.
The participants in the sensory analysis received the
DAP tea sample and a questionnaire containing two
questions to answer. For the overall evaluation of
the sample, the judges used the hedonic scale,
anchored at the ends with ‘like extremely’ (9) to
‘dislike extremely’ (1) as the acceptance test
(Queiroz & Treptow, 2006; Meilgaard, Civille, &
Carr, 1991). Also, the purchase intent for the tea was
evaluated, using a scale anchored between ‘certainly
would buy’ (5) to ‘certainly would not buy’ (1).
Statistical analysis
Analysis of variance (ANOVA) was used to test
the difference between the stages of development
(means), which were analyzed by the Tukey test at a
95% (p < 0.05) significance level using STATISTIC
software (StatSoft, 2004).
Results and discussion
Proximate composition
According to Table 1, the crude protein, fiber
and Nifext contents of INAP were 21.62, 191.24 and
113.45 respectively. All these values were greater
than those reported by Gondin et al. (2005) who
analyzed five fruit peels (avocado, pineapple, banana,
melon and passion fruit). The total lipids content
found in INAP is significant as compared with other
skins of fruits and vegetables (Rocha et al., 2008).
The INAP (P. americana) shows lipids, protein
and ash contents that are comparable or better than
other varieties of avocado reported in literature, of
which the variety 'Hass' has 1.01 and 1.77% lipids
and proteins, respectively, and the variety 'Fuerte'
shows only 0.32% (Rodríguez-Carpena et al., 2012).
The dehydration process of the avocado peel was
effective, with a loss of 93.5% water; in addition, it
appears that the other constituents were
concentrated, emphasizing the ash content, crude
protein, total fat, energy, and Nifext compared to in
natura avocado peel, with significant differences by
Tukey Test (p < 0.05).
The DAP can be considered a source of crude
fiber, with 415.00 ± 51.90 g kg
-1
; this value is greater
than other raw materials used in tea preparation,
such as yerba mate (14.49 per 100 g) (Esmelindro,

26 Rotta et al.
Acta Scientiarum. Technology Maringá, v. 38, n. 1, p. 23-29, Jan.-Mar., 2016
Toniazzo, Wackuz, Dariva, & Oliveira, 2002) and
inflorescence ginger (19.22 and 23.99 per 100 g)
(Lucio, Freitas, & Waszczynsky, 2010). Also, DAP
represents a source of protein and lipids with higher
levels than those found in the mango peel flour
(Aziz, Wong, Bhat, & Cheng, 2012).
The dehydrated peels contained significant ash
levels that are nutritionally important macro and
microminerals. These values demonstrate the
nutritional potential of the avocado peel for human
consumption.
Antioxidant activity and minerals
Spectrophotometric methods were used to
evaluate the amounts of total phenolic compounds
and flavonoids as well as the antioxidant activity by
DPPH and FRAP applied in the fruit peels (Wolfe,
Wu, & Liu, 2003; Abdullah, Zulkifli, Abdullah,
Aziman, & Kamarudin, 2012; Barros, Ferreira, &
Genovese, 2012). The results for TPC, FLAV, and
antioxidant activity, evaluated by the DPPH and
FRAP methods in INAP and DAP, are presented in
Table 2. INAP showed significant levels of TPCs
compared with reported by Peschel et al. (2006) for
residues from apple, pear and strawberry juice
production with 52.18 ± 4.80, 59.77 ± 4.24 and
18.41 ± 2.12 mg GAE g
-1
dry extract, respectively,
and the best values are also comparable with
carambola peel (Shui & Leong, 2006). Concerning
the amount of flavonoids found in INAP, it can be
seen that the values were higher than previously
reported for the soursop shell (8.2 mg EQ 100 g
-1
of
sample) (Loizzo et al., 2012).
DAP showed levels of TPCs (10848.27 ± 162.34
mg EAG kg
-1
) that were higher than dehydrated
carrot peel (1017 mg EAG 100 g
-1
) (Chantaro,
Devahastin, & Chiewchan, 2008). In DAP, a high
value of FLAs (1360.34 ± 188.65 mg EQ kg
-1
) was
found.
Antioxidant activity measured by the DPPH
assay in INAP showed a higher value (16.10 μmol
TE g
-1
) than citrus peel (6.00 to 8.50 μmol TE g
-1
)
(Barros et al., 2012). In the antioxidant activity
analysis of various fruit peel, using the FRAP
method, INAP exhibited a higher antioxidant
capacity than apricots (7.9 ± 0.7 μmol Fe
2
SO
4
.7H
2
O
g
-1
), Hami melons (5.2 ± 0.7 μmol Fe
2
SO
4
. 7H
2
O g
-1
),
and Duck pears (8.9 ± 0.8 μmol Fe
2
SO
4
.7H
2
O g
-1
)
(Guo et al., 2003).
The results showed the presence of TPCs and
FLAVs in avocado peel, which are responsible for
the observed antioxidant properties, owing to
their chemical constitution. The antioxidant
properties have been widely studied, owing to
their influence on the quality of food and the
importance of these compounds in maintaining
human health (Soares, 2002). After observing the
potential antioxidant activity of avocado peel,
especially the dehydrated peel, a tea was
developed in order to assess whether the
antioxidant properties of the DAP are transferred
to the water after infusion.
The amount of sodium (Na) and potassium (K)
found in DAP was 1.81 and 82.25 g kg
-1
respectively
and the amount of these minerals found in tea
prepared with DAP was 0.81 and 8.55 mg L
-1
,
respectively. All of these values are within the
recommended values (FAO, 1985), which indicate
that approximately 1 g sodium should be consumed
per day and they advise that a daily potassium
consumption of 3-4 g is enough to reduce blood
pressure may lessen the risk of a stroke.
The DAP tea has significant quantities of TPCs,
with 123.57 ± 4.64 and 110.20 ± 2.55 mg EAG L
-1
on
day 0 and 45, respectively, which are transferred to
the water after infusion. The verified TPC content
was higher than that found in apple tea (Table 3),
chamomile tea (11.61 ± 12.32 mg GAE g
-1
), and
anise tea (8.90 ± 1.26 mg GAE g
-1
) reported by
Souza, Oldini, Cabral, and Alencar (2011) it was also
similar to mate tea, which is widely marketed. The
reported TPC values for mulberry leaf tea (11.64 ±
0.99 mg GAE g
-1
) and Bamboo leaf tea (11.50 ± 0.82
mg GAE g
-1
) reported by Oh, Jo, Cho, Kim, and
Han (2013) are similar to the values found for DAP
tea in this work.
Table 1. Approximate composition and energy of in natura avocado peel (INAP) and dehydrated avocado peel (DAP).
Sample Moisture Ash Crude protein Total lipids Crude fiber Nifext Energy*
INAP 65.05
a
± 3.10 5.43
a
± 0.59 21.62
a
± 3.14 12.21
a
± 0.28 191.24
a
± 9.04 113.45
a
± 24.84 621.80
a
± 91.14
DAP 42.76
b
± 1.11 19.21
b
± 0.98 61.56
b
± 7.21 45.35
b
± 1.25 415.00
b
± 51.90 416.12
b
± 14.26 2214.87
b
± 52.77
Mean value ± standard deviation (n = 3). Results are expressed as g kg
-1
avocado peel. * Energy values are expressed as kcal kg
-1
. Nifext = carbohydrate content by difference.
A different letter in the same column shows significant difference at the 95% level by Tukey’s test (p < 0.05).
Table 2. Total phenolic compounds (TPCs), Flavonoids (FLAVs), FRAP, and DPPH assay in INAP and DAP.
TPC (mg GAE kg
-1
) FLAV (mg QE kg
-1
) FRAP (μmol Fe
2
SO
4
.7H
2
O g
-1
) DPPH (μmol TE g
-1
)
INAP
621.36
a
±
34.91 536.89
a
±
44.89 9.56
a
±
1.08 16.10
±
1.12
DAP
10848.27
b
±
162.34 1360.34
b
±
188.65 422.77
b
±
29.03 763.02
±
54.43
Mean value ± standard deviation (n = 3). Different letters in the same column shows significant difference at a 95% level by Tukey’s test (p < 0.05).

Avocado peel tea with antioxidant activity 27
Acta Scientiarum. Technology Maringá, v. 38, n. 1, p. 23-29, Jan.-Mar., 2016
Table 3. Results oftotal phenolic TPC, FLAV, FRAP, and DPPH assay in marketed teas and avocado-peel teas (APT) after 0 and 45 days
storage.
TPC
(mg GAE L
-1
)
FLAV
(mg QE L
-1
)
FRAP
(μmol Fe
2
SO
4
.7H
2
O L
-1
)
DPPH
(μmol TE L
-1
)
A
PT 0 da
y
s 123.57
a
±4.64 14.09
a
±2.71 2,166.71
a
±35.48 1954.24
a
±87.92
A
PT 45 da
y
s 110.20
a
±2.55 10.38
a
±1.64 1,900.90
a
±90.99 2518.27
a
±192.59
A
pple tea 20.72
b
±0.92 25.78
b
±2.66 2,777.88
b
±106.34 13497.51
b
±696.55
Mate tea 176.68
c
±6.12 83.42
c
±3.14 3,477.18
c
±169.63 2858.84
a
±14.87
Green tea 493.81
d
±10.23 134.21
d
±2.01 12,341.55
d
±344.19 2409.50
a
±86.10
Mean value ± standard deviation (n = 3). Different letters in the same column indicate a significant difference at the 95% level by Tukey’s test (p < 0.05).
In order to compare the antioxidant activity of
the avocado-peel teas with other marketed teas, the
DPPH assay (through free radicals) was used, which
showed that tea from the avocado peel is similar to
mate tea, which is also consumed as it has
antioxidant properties. When the avocado-peel teas
were evaluated after different storage periods (0 and
45 days), the amount of TPCs and FLAV present in
the teas showed no statistical difference, proving that
the avocado-peel tea is stable in terms of product
storage. There was no significant difference in the
analysis of antioxidant activity by the FRAP and
DPPH assays during the storage of the teas.
The correlation between the results of the
DPPH and FRAP methods for the TPC and FLAV
contents in some marketed teas and in the avocado-
peel teas are shown in Figure 1. There is a positive
correlation between FLAV/FRAP (0.8948),
TPC/FRAP (0.9948), and TPC/FLAV (0.8867),
which suggests that flavonoid compounds and
phenolic compounds contribute towards the
antioxidant activity seen by the FRAP assay.
Figure 1. Pearson correlation between antioxidant activity assays
and the phenolic (TPC)and flavonoids (FLAV) compounds
present in market and avocado peel teas.
Antioxidant capacity methods can be divided into
two types based on hydrogen atom transfer (HAT)
reactions and electron transfer (ET) reactions,
depending on how the radicals are deactivated by the
antioxidants (Huang, Ou, & Prior, 2005). For TPC
determination by the Folin–Ciocalteu reagent, both
the FLAV and FRAP methods are considered to be
ET methods. This classification can explain the high
correlation coefficients shown in Figure 1.
Microbiological control
According to Brasil (2001) in terms of the
microbiological standards for foods, tea and others
similar drinks should not contain any Salmonella spp.
and can only include the maximum amount of 2.0
MPN (most probable number) mL
-1
fecal coliforms.
For both tea storage periods (0 and 45 days), the values
of fecal coliforms were less than 0.3 Ml MPN and
there was an absence of Salmonella spp in the samples.
The results indicate that the processing and storage of
the DAP sachets as proposed for the manufactured tea,
provides a food that is free of microbial contamination
and has a considerable shelf life (FDA, 1995).
Sensory analysis
The samples were presented to volunteers for
sensory analysis and the acceptance test result was
7.00 ± 1.09, where (7) means 'like moderately'. A
total of 66% of the panelists chose 'like' or 'like
moderately' for the DAP tea, indicating that the
product was not rejected by the panelists.
According to the purchase intention test, the
result was 4.00 ± 0.87, where (4) indicates 'probably
buy'. Further analysing the purchase intention test
through Figure 2, it could be seen that, on average,
37% of the panelists might buy, 42% would probably
buy, and 13% would certainly buy, indicating that
tea from DAP has a potential market.
Total of panelis
t
Purchase intention test values
Figure 2. Purchase intention test to dehydrated avocado peel tea.
The flavor and taste of teas were considered
essential for the quality attributes of the product in

28 Rotta et al.
Acta Scientiarum. Technology Maringá, v. 38, n. 1, p. 23-29, Jan.-Mar., 2016
order for the teas to be marketed (Sinija & Mishra,
2011). Sensory analysis was needed to verify the
responsiveness of the new product by consumers,
because sensory analysis is the final criterion for
acceptance or rejection of food (Falade & Omojola,
2010).
According to the acceptance test, there was no
rejection of the DAP tea among the panelists, who
also showed intent to purchase a new product if it
was to be marketed.
Conclusion
Fruit peels, such as avocado peel, are not
generally consumed and are therefore discarded.
After an investigation on the properties avocado
peel, it was noted as a source of nutrients and
subsequently, a tea formulation was suggested as a
way of reusing these discarded peels. Phenolic and
flavonoid compounds were present in the avocado
peel and the notable antioxidant activity of this tea
resembles the widely marketed mate tea. Sensory
analysis of the avocado-peel tea indicated that it has
promising effect on the consumer market.
Acknowledgements
The authors acknowledge Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq)
for financially supporting this research.
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Received on September 26, 2014.
Accepted on September 21, 2015.
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