Utilization of Eureka Lemon Peel for Development of Value Added Product

Abstract

The main purpose of this study was to prepare a delicious value added product from the osmo-dried eureka lemon peel flakes which otherwise is a wastage material. The peels of eureka lemon were used to prepare flakes. Plain water was used for washing of flakes, thereafter after washing these were blanched for five minutes and dipped in sugar and jaggery syrup concentrations as per the treatment combinations for 24 hours. In another 24 hours, the peel flakes were dried in cabinet tray drier (60°C) for 4-5 hours after draining out the water. Thereafter, the peel flakes were packed in LDPE bags and then stored at room temperature for 3 months. At the interval of 1 month, the various chemical and sensory characters were investigated. Osmo-dried eureka lemon peel flakes showed a decreasing trend in L* value, b* value, ascorbic acid and β-Carotene whereas an increasing trend was observed in reducing sugar, total sugar and a* value during storage period of three months. On the basis of overall acceptability, treatment T 7 (75°Brix sugar syrup) was found to be the most preferred osmo-dried eureka lemon peel flakes. It could be concluded that osmo-dried eureka lemon peel flakes can be preserved safely for three months.

Full text

Journal of Scientific & Industrial Research
Vol. 80, February 2021, pp. 181-185
Utilization of Eureka Lemon Peel for Development of Value Added Product
Pawandeep Kour, Neeraj Gupta* and Jagmohan Singh
Division of FST, SKUAST-J, Chatha, J&K UT 180 009
Received 21 May 2020; revised 29 September 2020; accepted 01 December 2020
The main purpose of this study was to prepare a delicious value added product from the osmo-dried eureka lemon peel
flakes which otherwise is a wastage material. The peels of eureka lemon were used to prepare flakes. Plain water was used
for washing of flakes, thereafter after washing these were blanched for five minutes and dipped in sugar and jaggery syrup
concentrations as per the treatment combinations for 24 hours. In another 24 hours, the peel flakes were dried in cabinet tray
drier (60°C) for 4–5 hours after draining out the water. Thereafter, the peel flakes were packed in LDPE bags and then
stored at room temperature for 3 months. At the interval of 1 month, the various chemical and sensory characters were
investigated. Osmo-dried eureka lemon peel flakes showed a decreasing trend in L* value, b* value, ascorbic acid and β-
Carotene whereas an increasing trend was observed in reducing sugar, total sugar and a* value during storage period of three
months. On the basis of overall acceptability, treatment T7 (75°Brix sugar syrup) was found to be the most preferred osmo-
dried eureka lemon peel flakes. It could be concluded that osmo-dried eureka lemon peel flakes can be preserved safely for
three months.
Keywords: Flakes, Jaggery, Osmo-dried, Sensory evaluation, Sugar
Introduction
Due to its peculiar nature, eureka lemon (Citrus
limon B) is grown up as a significant fruit which can
be easily grown in dry and semi-dry areas of India
due to its spineless and hefty fruit bearing nature.1 It
is high in vitamin C content which gave a solid
protection against various diseases and contributes to
a strong immune system and also contains
phytochemicals, flavonoids giving it a greater
antioxidant boost. Eureka lemon is generally utilized
for making pickles, culinary purposes and for
blending with other fruit juices for preparation of
squash at small and large scale. Generally, left over
pomace and peel of eureka lemon fruit after the
extraction of juice is discarded as waste. Peel that
constitutes 25–35 percent of fruit weight is quite
nutritious but got wasted and could not fetch any
economical price to the industry.2 Besides the
utilization of residual waste as cattle feed, the other
useful option is to utilize waste eureka lemon peel for
developed value added product. Thus, citrus
processing industry can easily opt for making candied
peel which finds the ready market in confectionary.
The peel candy can be consumed as such or in the
form of value added products like steamed pudding
etc. where it can be incorporated to improve
consumer’s acceptability of such products. The
various other industries like cake, biscuits and breads,
the candied citrus fruit rinds can be used safely. These
can be marketed as mixed candied fruits and can also
be consumed as such.3 Osmotic dehydration is one of
the most effective food preservation techniques in the
processing of dehydrated foods. Dehydration is
mainly the process of removal of water from natural
materials such as fruits and vegetables and is mainly
done by dipping the material in high osmotic pressure
aqueous solution generally made by dissolving sugar
and salts. For vegetables, common salt is used
whereas sucrose for fruits.4 This work was mainly
planned with major objective to minimize the wastage
of eureka lemon peel and to develop value added
product i.e osmo-dried eureka lemon peel flakes.
Materials and Methods
The fully matured Eureka lemon fruits were
procured from RRSS, SKUAST-J, Raya, Samba (J&K
UT) and were taken to Division of FST, SKUAST-J
for further processing. The fruit was used for squash
and the waste material i.e. peel was used for making
osmo-dried eureka lemon peel flakes. Peels of almost
same size were selected for the processing of the peel
flakes. The peel flakes were washed thoroughly in tap
water and were subjected to pre-treatment like
——————
*Author for Correspondence
E-mail: neeruguptapht@gmail.com

J SCI IND RES VOL 80 FEBRUARY 2021
182
blanching. On the other hand, sugar and jaggery syrup
of different concentrations/treatments (50, 55, 60, 65,
70 and 75°Brix) were prepared. In control, no sugar or
jaggery dipping treatment was applied. After
blanching, the peel flakes were dipped in sugar and
jaggery syrup, boiled for 2–3 min and kept for 24 h
according to the treatment combination. After
completion of dipping time, sugar and jaggery syrup
was drained and then osmo-dried peel flakes were
spread on trays. The osmo-dried peel flakes were
dried for 4–5 h at 60°C. After drying, the peel flakes
were collected and packed in LDPE bags and stored at
room temperature for a period of three months. The
osmo-dried eureka lemon peel flakes were analyzed at
an interval of 0, 1, 2 and 3 months of storage for
chemical and organoleptic evaluation. The method of
Lane and Eynon’s was followed for the determination
of reducing and total sugars.5 Ascorbic acid was
estimated by using 2-6, dichlorophenol indophenol
dye.5 β-Carotene was determined using an ultra-
violet-visible recording spectrophotometer at 452 nm
as per the method.5 The hunter colour values (L*, a*
& b*) were determined as per the method of
Grabowski et al.6 Organoleptic evaluation was carried
out by a panel of minimum 10 semi-trained judges on
9-point hedonic rating scale.7 The data obtained was
statistically analyzed using CRD factorial for
interpretation of results through analysis of variance.8
Results and Discussion
Reducing Sugar
Initially the statistically higher reducing sugar
(19.08 percent) noted in T7 (75°Brix sugar syrup),
however lowest (6.50 percent) recorded in control,
which increased significantly after three months of
storage period. The same treatment (75°Brix sugar
syrup) recorded statistically higher reducing sugar
content (20.90 percent) and was followed by T6
(70°Brix sugar syrup). However, statistically lower
value (6.98 percent) of reducing sugar observed in
control. On the basis of overall mean values, it was
observed that higher reducing sugar (19.95%) was
observed in 75°Brix syrup and lowest of 6.76 percent
in control. The treatment, storage as well as
interaction between different treatments over the
various storage periods were found to be significant
(Table 1). The conversion of non-reducing sugars to
reducing sugars and hydrolysis of polysaccharides
might be the reason for increment of reducing sugars
during the various storage periods. Results obtained
with amla jam9 and bael preserve10 are in accordance
with the findings of this research.
Total Sugar
Treatment 75°Brix sugar syrup observed
significantly higher amount of total sugar content
(69.90 percent), however, statistically lower total
sugar content i.e., 7.85 percent was observed in
control (Table 1). Statistically significant total sugar
content (72.40%) recorded in 75°Brix sugar syrup
treatment; also the values of total sugars had
increased during the advancement in storage periods.
However, after 3 months of storage minimum value of
total sugar (8.95 percent) was recorded in control.
Mean values for storage of total sugar in eureka
lemon peel flakes increased significantly from 50.20
to 52.58 percent. The conversion of polysaccharides
into monosaccharides might be the possible reason for
a continuous enhancement in total sugar content
during 0 month of storage to 3 months of storage.
Similar findings were also reported in ber chuhara.11
Ascorbic Acid
Statistically considerable decrease in ascorbic acid
in eureka lemon peel flakes was recorded during
storage (Table 1). Higher values of ascorbic acid
(11.70 mg/100 g) observed in 50°Brix sugar syrup
treatment which was immediately followed by
treatment T3 (55°Brix sugar syrup) and statistically
lower value (7.05 mg/100 g) observed in control (T1)
initially. After three months of storage period ascorbic
acid content decreased and highest value (5.10
mg/100 g) noticed in 50°Brix syrup, whereas control
evinced the minimum value (1.71 mg/100 g). During
the different storage periods mean values of ascorbic
acid reduced from 10.60 to 4.10 mg/100 g. The
treatment, storage as well as interaction between them
in various storage periods were significant. The
ascorbic acid present in eureka lemon peel flakes
might have destroyed during processing and also
afterwards during storage. The possible reason behind
it could be that as ascorbic acid is sensitive to heat
and thus oxidized rapidly in the presence of oxygen.
The decreasing trend in ascorbic acid during different
storage periods had also been reported in Galgal peel
sticks12 and Karonda candy.13
β-Carotene
At beginning, significantly higher amount of β-
Carotene to the tune of 11.12 mg/100 g was recorded

KOUR et al.: UTILIZATION OF EUREKA LEMON PEEL FOR VALUE ADDED PRODUCT
183
in treatment T13 (75°Brix jaggery syrup) and
significantly lower value (4.45 mg/100 g) in control.
As the storage period advanced, β-Carotene decreased
and the minimum value (4.31 mg/100 g) observed in
control, however maximum value (11.00 mg/100 g)
was found in T13 (75°Brix jaggery syrup) after three
months of storage. The storage mean values of β-
Carotene decreased from 9.98 to 9.86 mg/100 g
(Table 1). However, the interaction between different
storage periods and treatment combinations was
recorded to be significant. Various factors like
oxidation and its stimulation due to presence of light,
temperature and enzyme have further accelerated the
process. Similar results were also reported in Kinnow
peel candy14 and in dehydrated carrot slices.15
Hunter Color Values
Colour is the most important attribute of food items
for consumer acceptability. The initial mean value of
L* value decreased significantly from 47.90 to 46.88,
a* value increased significantly from 5.34 to 6.02 and
b* value also decreased significantly from 21.84 to
21.73 during three months of storage (Table 2). This
might be due to the increased rate of Millard reaction
because of the availability of more sugar. Muzzaffar
et al.16 reported similar changes in L*, a* and b*
values, they attributed this to occurrence of non-
enzymatic browning that results in darkening of the
product thus decreased L* value, a* value showed
increase during storage of pumpkin candy. They
further reported that degradation of carotene pigment
also take place during storage thus was responsible
for the decrease in b* value.
Overall Acceptability
A significant decline in overall acceptability score
of eureka lemon peel flakes were recorded during the
different storage time (Table 2). During the storage of
three months, overall acceptability declined
significantly from 8.11 to 7.93. mean storage.
Statistically higher overall acceptability score (8.50)
recorded in 75°Brix sugar syrup treatment and it was
Table 1 — Effect of treatments and storage period on reducing sugar (%), total sugar (%), ascorbic acid (mg/100 g) and
β-Carotene (mg/100 g) of osmo-dried eureka lemon peel flakes
Treatments
Reducing sugar
Total sugar
Ascorbic acid
β-Carotene
Storage period (months)
Storage period (months)
Storage period (months)
Storage period (months)
0
1
2
3
Mean
0
1
2
3
Mean
0
1
2
3
Mean
0
1
2
3
Mean
T1 (Control)
6.50
6.71
6.85
6.98
6.76
7.85
8.21
8.51
8.95
8.38
7.05
4.81
3.15
1.71
4.18
4.45
4.40
4.36
4.31
4.38
T2 (50°Brix
sugar syrup)
16.35
16.85
17.40
18.02
17.15
42.95
43.65
44.56
45.47
44.15
11.71
7.97
6.11
5.10
7.72
9.78
9.73
9.69
9.65
9.71
T3 (55°Brix
sugar syrup)
16.90
17.42
18.05
18.68
17.76
47.49
48.05
49.04
50.02
48.65
11.63
7.93
6.06
5.00
7.65
9.85
9.81
9.78
9.74
9.79
T4 (60°Brix
sugar syrup)
17.62
18.10
18.72
19.32
18.44
52.10
52.85
53.75
54.61
53.32
11.56
7.76
5.51
4.90
7.43
9.89
9.83
9.79
9.76
9.82
T5 (65°Brix
sugar syrup)
18.10
18.68
19.25
19.81
18.96
58.05
59.00
60.13
61.06
59.56
11.39
7.49
5.49
4.81
7.29
9.95
9.91
9.88
9.86
9.90
T6 (70°Brix
sugar syrup)
18.76
19.20
19.78
20.32
19.51
64.21
65.05
65.90
66.85
65.50
11.32
7.30
5.35
4.75
7.18
10.02
9.96
9.91
9.88
9.94
T7 (75°Brix
sugar syrup)
19.08
19.62
20.22
20.90
19.95
69.90
70.66
71.51
72.40
71.11
11.15
7.25
5.18
4.54
7.03
10.09
9.99
9.94
9.91
9.98
T8 (50°Brix
jaggery syrup)
14.95
15.52
16.05
16.48
15.75
41.05
41.69
42.49
43.35
42.14
10.66
5.48
4.45
4.00
6.14
10.81
10.78
10.74
10.71
10.76
T9 (55°Brix
jaggery syrup)
15.35
15.75
16.25
16.61
15.99
44.90
45.51
46.37
47.21
46.00
10.59
5.30
4.37
3.91
6.04
10.86
10.82
10.79
10.74
10.80
T10 (60°Brix
jaggery syrup)
15.78
16.22
16.71
17.20
16.48
49.25
49.87
50.76
51.53
50.35
10.42
5.28
4.10
3.82
5.90
10.94
10.91
10.88
10.86
10.89
T11 (65°Brix
jaggery syrup)
16.12
16.60
17.05
17.52
16.82
53.81
54.49
55.31
56.12
54.93
10.25
5.15
3.90
3.75
5.76
10.99
10.93
10.88
10.84
10.91
T12 (70°Brix
jaggery syrup)
16.38
16.85
17.40
17.91
17.13
58.02
58.77
59.65
60.45
59.22
10.18
4.95
3.81
3.64
5.64
11.06
11.00
10.95
10.93
10.98
T13 (75°Brix
jaggery syrup)
16.92
17.41
17.95
18.45
17.68
63.05
63.84
64.72
65.57
64.29
10.01
4.75
3.75
3.49
5.50
11.12
11.07
11.03
11.00
11.05
Mean
16.06
16.53
17.05
17.55
50.20
50.89
51.74
52.58
10.60
6.26
4.71
4.10
9.98
9.93
9.89
9.86
CD (5%)
Treatments
0.02
0.01
0.02
0.01
Storage
0.01
0.03
0.01
0.02
Treatments x
storage
0.03
0.04
0.03
0.03

J SCI IND RES VOL 80 FEBRUARY 2021
184
closely followed by treatment 70°Brix sugar syrup;
however, control envisaged the statistically lower
score value of 6.81. However, the similar pattern was
followed during three months storage. The data was
found statistical significant at 0, 1, 2 and 3 months of
storage. During the different storage periods there
might be changes in chemical composition of the
product which could have facilitated in loss of various
factors like colour, taste and texture. Similar findings
have also been reported in citron peel candy17 and in
intermediate moisture beetroot cubes.18
Conclusion
The results of the present study on preparation of
eureka lemon peel flakes revealed that peels of eureka
lemon which otherwise are discarded can be well
utilized properly to yield nutritious, attractive value
added product. On the basis of overall acceptability,
osmo-dried peel flakes of eureka lemon prepared from
treatment 75°Brix sugar syrup proved to be superior
in comparison to other treatment combinations. This
will also improve the effective utilization of waste of
eureka lemon and also add value to citrus fruit and
benefits to growers thus increasing their income and a
step towards doubling of farmers’ income.
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Table 2 — Effect of treatments and storage period on lightness (L* value), redness (a* value), yellowness (b* value)
and overall acceptability of osmo-dried eureka lemon peel flakes
Treatments
Lightness (L* value)
Redness (a* value)
Yellowness (b* value)
Overall acceptability
Storage period (months)
Storage period (months)
Storage period (months)
Storage period (months)
0
1
2
3
Mean
0
1
2
3
Mean
0
1
2
3
Mean
0
1
2
3
Mean
T1 (Control)
43.15
42.75
41.95
41.10
42.24
3.75
3.95
4.20
4.71
4.15
18.81
18.79
18.76
18.74
18.77
6.99
6.82
6.75
6.70
6.81
T2 (50°Brix
sugar syrup)
49.75
49.15
48.85
48.60
49.09
4.10
4.32
4.52
4.85
4.45
22.96
22.96
22.91
22.88
22.93
8.10
8.02
7.94
7.88
7.99
T3 (55°Brix
sugar syrup)
49.26
48.85
48.56
48.30
48.74
4.55
4.62
4.84
5.09
4.78
22.91
22.88
22.85
22.81
22.86
8.21
8.15
8.10
8.06
8.13
T4 (60°Brix
sugar syrup)
48.80
48.64
48.10
47.91
48.36
4.88
5.08
5.32
5.59
5.22
22.87
22.84
22.80
22.76
22.82
8.30
8.21
8.13
8.07
8.18
T5 (65°Brix
sugar syrup)
48.41
48.15
47.75
47.50
47.95
5.30
5.52
5.75
6.01
5.64
22.80
22.81
22.78
22.75
22.78
8.42
8.38
8.33
8.29
8.35
T6 (70°Brix
sugar syrup)
48.00
47.66
47.20
46.94
47.4
5.75
5.70
6.12
6.40
5.99
22.78
22.75
22.71
22.68
22.73
8.50
8.41
8.34
8.30
8.39
T7 (75°Brix
sugar syrup)
47.65
47.15
46.85
46.65
47.07
6.10
6.25
6.45
6.75
6.39
22.73
22.69
22.66
22.62
22.67
8.58
8.52
8.48
8.42
8.50
T8 (50°Brix
jaggery syrup)
49.00
48.56
48.20
47.99
48.44
4.65
4.79
5.02
5.27
4.93
21.50
21.45
21.41
21.38
21.43
7.80
7.74
7.69
7.65
7.72
T9 (55°Brix
jaggery syrup)
48.55
48.10
47.84
47.60
48.02
5.09
5.28
5.48
5.75
5.40
21.40
21.40
21.35
21.31
21.36
7.91
7.85
7.80
7.76
7.83
T10 (60°Brix
jaggery syrup)
48.10
47.85
47.50
47.23
47.67
5.57
5.75
5.98
6.25
5.89
21.37
21.34
21.30
21.26
21.32
7.93
7.94
7.89
7.75
7.88
T11 (65°Brix
jaggery syrup)
47.75
47.49
47.16
46.90
47.33
6.05
6.20
6.45
6.69
6.35
21.31
21.29
21.25
21.22
21.27
8.10
8.03
7.98
7.94
8.01
T12 (70°Brix
jaggery syrup)
47.28
47.10
46.80
46.55
46.93
6.55
6.70
6.92
7.25
6.86
21.26
21.21
21.17
21.13
21.19
8.24
8.17
8.11
8.06
8.14
T13 (75°Brix
jaggery syrup)
47.00
46.65
46.40
46.18
46.56
7.02
7.19
7.42
7.64
7.32
21.20
21.15
21.11
21.07
21.13
8.38
8.32
8.27
8.23
8.30
Mean
47.90
47.55
47.17
46.88
5.34
5.49
5.73
6.02
21.84
21.81
21.77
21.74
8.11
8.04
7.99
7.93
CD (5%)
Treatments
0.04
0.04
0.05
0.03
Storage
0.02
0.02
0.03
0.01
Treatments x
storage
0.08
0.09
NS
0.05

KOUR et al.: UTILIZATION OF EUREKA LEMON PEEL FOR VALUE ADDED PRODUCT
185
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