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Impact of foliar spray of nano-Zn and nano-Cu on biochemical
characteristics of guava cv. Allahabad Safeda
Lakshya
Department of Horticulture, School of Agriculture, Lovely Professional University,
Phagwara, India
Manish Bakshi*
Department of Horticulture, School of Agriculture, Lovely Professional University,
Phagwara, India
Pallvi Verma
Department of Horticulture, School of Agriculture, Lovely Professional University,
Phagwara, India
Anis Ahmad Mirza
Department of Horticulture, School of Agriculture, Lovely Professional University,
Phagwara, India
Shailesh Kumar Singh
Department of Horticulture, School of Agriculture, Lovely Professional University,
Phagwara, Punjab, India
Suhel Mehndi
Department of Genetics and Plant Breeding, School of Agriculture, Lovely Professional
University, Phagwara, Punjab, India
*Corresponding author. E-mail: manish.bakshi78@gmail.com
Article Info
https://doi.org/10.31018/
jans.v16i1.5243
Received: October 31, 2023
Revised: February 1, 2024
Accepted: February 11, 2024
This work is licensed under Attribution-Non Commerc ial 4.0 International (CC BY-NC 4.0). © : Author (s). Publishing rights @ ANSF.
239 - 244
ISSN : 0974-9411 (Print), 2231-5209 (Online)
journals.ansfoundation.org
Research Article
INTRODUCTION
Guava is a fruit that is native to Central and South
America. The distribution of guava was aided by hu-
mans and other living organisms (Hussain et al., 2021).
The fruit is rich in vitamin C, lycopene, polyphenols,
sugars, fiber, calcium, minerals, and calories (Anand et
al., 2020). Due to its high nutritional value and inexpen-
sive availability, it is known as the poor man's apple
(Mali et al., 2023). Although guava fruit is generally
consumed in its fresh form, it is used to make many
different items, including jam, jelly, canned fruit, and
Abstract
Foliar spraying of nanoparticles (NPs) improves the absorption of plant nutrient application compared to traditional soil–root
application, and it also enhances the yield and quality of fruits. The present study aimed to evaluate the qualitative effects of
foliar sprays of two concentrations of nano-zinc and nano-copper (40 ppm, 60 ppm; 20 ppm, 30 ppm respectively), in compari-
son to ZnSo4 (recommended by, Punjab Agriculture University, Ludhiana) and control (foliar spray of water) on the guava crop
(var. Allahabad Safeda). The experiment was conducted at Lovely Professional University Research farm, Phagwara, Jalandhar
(Punjab) by applying a simple randomized block design, with ten treatments applied as T1: control, T2: nano-Zn1, T3: nano-Zn2,
T4: nano-Cu1, T5: nano-Cu2, T6: nano-Zn1+ nano-Cu1, T7: nano-Zn1+ nano-Cu2, T8: nano-Zn2 + nano-Cu1, T9: nano-Zn2 + nano-
Cu2, T10: ZnSO4 (PAU recommendation) in three replications. The treatments were sprayed two times, first at the flowering
stage and second when the fruit reached pea size. The nutrient spray increases the concentration of nutrients in the leaves
while also affecting the biochemical parameters. The performance for total soluble solids (9.89°B), total sugars
(8.74%), titratable acidity (0.98%), antioxidants (7.49%), firmness (5.71kg/cm2), non-reducing sugars (3.32%), Vitamin-C
(268.90mg/100g pulp), pectin content (2.13%), reducing sugars (5.46%), and TSS/acid ratio (10.06) was superior with the appli-
cation of nano-Zn2 + nano-Cu2 (T9). The application of nano-micronutrients (zinc and copper) in combination is favorable for the
quality of guava fruit (Allahabad Safeda).
Keywords: Foliar application, Guava, nano-Cu, Nano-nutrients, Nano-Zn
How to Cite
Lakshya et al. (2024). Impact of foliar spray of nano-Zn and nano-Cu on biochemical characteristics of guava cv. Allahabad
Safeda. Journal of Applied and Natural Science, 16(1), 239 - 244. https://doi.org/10.31018/jans.v16i1.5243
240
Lakshya et al. / J. Appl. & Nat. Sci. 16(1), 239 - 244 (2024)
sharbat (A. Singh et al., 2019). Fruits are a crucial com-
ponent of a healthy diet; consuming them can help pre-
vent serious illnesses. Unfortunately, eating too little
fruits and vegetables, especially in poorer nations, is
one of the risk factors for death. According to estimates
from the Global Burden of Disease study, eating less
fruit is associated with close to 3.4 million deaths
(Mokdad et al., 2016). The population of the globe is
expected to reach 9.1 billion people by 2050, placing us
under ongoing population pressure (Fao, 2009). In the
end, it is noted that the demand for food also increases
as the population (Kumar et al., 2019). The degradation
of land, which is brought on by resource constraints and
urbanization, is a substantial obstacle to agricultural
production. For the past 50 years, farmers have re-
quested pesticides fertilizers, and disease-free cultivars
to solve this problem (Yadav, 2014).
In the absence of the macro-nutrients nitrogen, phos-
phorus, potassium, calcium, magnesium, and sulphur,
the guava is a nutrient-responsive crop and is said to
exhibit recognizable symptoms of malnutrition. Micronu-
trient deficiencies are also reportedly present. As a re-
sult, field trials and leaf nutrient content have been ad-
vised for monitoring guava's nutritional needs
(Mahaveer and Sangma, 2017). In actuality, fertilizers
have been shown to be crucial in increasing the output
of field crops in general and fruits in particular. Alt-
hough, the overuse of chemical fertilizers has led to a
decline in soil health and food quality (Baweja et al.,
2020). The increase in agricultural productivity by nano-
technology has great potential to contribute to long-term
food security. Qureshi et al., (2018) defined nano-
fertilizers as nanomaterials with a 1–100 nm diameter
that provide plants with at least one type of nutrient.
These characteristics include large surfaces, high ab-
sorption capacities, smooth delivery systems, and regu-
lated release kinetics to active areas (Solanki et al.,
2015). Numerous nanomaterials have demonstrated a
significant potential for improving the quality and pro-
duction of horticulture crops, their shelf life, and post-
harvest damage (Rana et al., 2021).
The trace element zinc (Zn) is essential for normal plant
metabolic and physiological activities. Zn availability is
confined to the rhizosphere, so the maximum farmed
land remains Zn deficient, restricting plant nutrient ab-
sorption. Because of their tiny size and wide surface
area, Zn nanoparticles are efficiently transported into
plant systems (Chandrakala et al., 2022). Copper (Cu)
is an active essential micronutrient for plant physiology
and metabolic enzymatic reactions. In addition, it con-
tributes to the transfer of electrons in the redox reac-
tion. That is why copper is used as an essential nutrient
and needs to be supplied through fertilizer in plants
(Francis et al., 2022).
Nano-fertilizers are substances on the nanoscale that
include micronutrients and macronutrients and are used
for supplying nutrients to plants (Fatima et al., 2021;
Adisa et al., 2019; Bisma et al., 2020). They are more
reactive and penetrate the soil and plant deeper due to
their increased surface area to volume ratio
(Manjunatha et al., 2016). Additionally, nano-fertilizers
are needed in tiny amounts because of their steady and
prolonged material release, which increases plant
productivity and encourages effective nutrient use that
can be considered climate-friendly. The features for
focused delivery can support precision and sustainable
agriculture in their potential (Iqbal, 2019; Zulfiqar et al.,
2019).
MATERIALS AND METHODS
The study was conducted on guava plants (var. Allaha-
bad safeda) that were 4-5 years of age, having uniform
shape, size, and Vigor, at Horticulture Farms, Depart-
ment of Horticulture, Lovely Professional University,
Punjab. Three replications of a randomized block de-
sign were employed for the experiment. N:P:K and
Farm yard manure were applied to the respective treat-
ments as per the recommendation in the Package of
Practice (PAU) for the guava plants (July, 2021). Foliar
application of different levels of nano zinc and nano cop-
per were used and the results were compared to the rec-
ommended foliar application of micronutrients. A total of
10 treatments replicated thrice were evaluated in a ran-
domized block design: T1: control, T2: nano-Zn1, T3:
nano-Zn2, T4: nano-Cu1, T5: nano-Cu2, T6: nano-Zn1+
nano-Cu1, T7: nano-Zn1+ nano-Cu2, T8: nano-Zn2 + nano
-Cu1, T9: nano-Zn2 + nano-Cu2, T10: ZnSO4 (PAU rec-
ommendation). The first dose of nano-nutrients was
applied at the flowering stage (June) and the next dose
after the fruit came into the pea stage (i.e.; the third
week of July). Nano-Zn1 is 40ppm, nano-Zn2 is 60ppm,
nano-Cu1 is 20ppm, nano-Cu2 is 30ppm, and 1% solu-
tion of zinc sulphate as per treatments. The solution of
4-5liters of water was prepared for spraying each plant.
Fruits were harvested in the first month of November to
analyze quality parameters (total sugars, reducing sug-
ars, non-reducing sugars, Vit C, pectin content, total
soluble solids (TSS), Titratable Acidity, and TSS: TA
ratio, antioxidants and firmness).
Collection and biochemical analysis of guava fruit
samples
The collection and detailed analysis of guava fruit sam-
ples were performed to investigate various physio-
chemical characteristics. Ten fruits were systematically
selected from each treated guava plant, and the follow-
ing parameters were assessed according to the proto-
col outlined by Ranganna, (1986).
Total soluble solids (°Brix)
A digital refractometer (0-32 °Brix) was employed to
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Lakshya et al. / J. Appl. & Nat. Sci. 16(1), 239 - 244 (2024)
determine the total soluble solids content. A few drops
of ripe fruit juice were placed on the refractometer's
prism, with prior calibration using purified water, and
the results were expressed in °Brix units.
Titratable acidity (%)
The titratable acidity of the fruit juice was assessed
using the method described by (Ranganna, 1986). This
involved the combination of 5 mL of fruit extract with 4–
5 drops of 1% phenolphthalein indicator, followed by
titration with 0.1 N NaOH. The endpoint of the titration
was indicated by the appearance of a light pink color,
which was maintained for at least 50 seconds. Titrata-
ble acidity was calculated using the formula:
Titratable acidity (%) = (56.1 × (V × N)) / W Eq. 1
Where:
V = Volume in mL of standard sodium hydroxide used.
N = Normality of the sodium hydroxide solution.
W = Weight in grams of the sample.
Antioxidants (%)
The DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, based
on the Chen et al., (2013)method, was slightly adapted.
A stock solution of 24 mg DPPH in 100 mL of methanol
was prepared and maintained at 20°C. A working solu-
tion was created by combining 10 mL of the stock solu-
tion with 45 mL of methanol, resulting in an absorbance
of 1.17 ± 0.02 units at 515 nm. Fruit extracts (150 mL)
were allowed to react with 2850 mL of the DPPH solu-
tion in the dark for 24 hours, and absorbance was
measured at 515 nm. Antioxidant results were ex-
pressed in mM TE (Trolox Equivalents) per gram of
fresh mass.
Total sugars (%)
The estimation of total sugars involved the use of an-
throne reagent with fruit juice. After subjecting the sam-
ple to a water bath at 100°C for 8 minutes and measur-
ing the optical density (O.D.) at 630 nm, the total sugar
content was calculated using the formula:
Total sugars (%) = ((mg of glucose) / (Volume of the
test sample)) × 100 Eq. 2
Reducing sugars (%)
The Nelson–Somogyi method was employed to deter-
mine how to reduce sugars. By taking 1 mL of guava
juice, making the volume up to 3 mL with distilled wa-
ter, and using DNS reagent, reducing sugars were
quantified based on a standard curve established using
glucose (0-500 µg).
Non-reducing sugars (%)
Non-reducing sugars were calculated by subtracting
the reducing sugar content from the total sugar
content.
TSS/Acidity Ratio
This ratio, indicating the balance between sugar con-
tent (TSS) and acidity, was calculated by dividing TSS
(in °Brix) by titratable acidity.
Firmness (kg/cm²)
The firmness of selected fruits was measured using a
penetrometer, which provided readings displayed on a
dial.
Vitamin C (Ascorbic acid) (mg/100g Pulp)
Ascorbic acid content was determined via a titration
method using a standard dye solution.
Pectin content (%)
Pectin content in guava fruit was calculated using a
modified version of Ranganna, (1977) method, where
pectin precipitates as calcium pectate from an acidified
solution. The quantification of pectin content was ex-
pressed as a percentage.
Statistical analysis
Data were statistically assessed using analysis of vari-
ance (ANOVA) to determine the importance of the ma-
jor components and the relevance of interactions. The
combined analysis of variance was conducted on the
assumption that the environment (years and blocks)
and treatments were fixed variables. The statistical
analysis system, SAS (SAS Institute Inc., Cary, NC,
USA), base 9 software was used to analyze the data.
Means were compared using Duncan's multiple range
test at the p 0.05 level. The data were statistically ana-
lyzed using the SPSS V. 23 program, and homogenous
subgroups were found to test the level of significance
between various treatments.
RESULTS AND DISCUSSION
The foliar application of nano-Zn and nano-Cu was
observed to have a significant impact on the quality of
guava fruits (Allahabad Safeda), affecting parameters
such as total soluble solids (TSS), titratable acidity,
ascorbic acid content, antioxidants, firmness, pectin
content, total sugars, reducing sugars, and non-
reducing sugars as displayed in Table 1. The results
indicated that the application of nano-zinc and nano-
copper, either individually or in combination, led to an
improvement in the quality of guava fruits. In contrast,
untreated plants produced smaller-sized and compara-
tively lighter fruits. The foliar application of nano-zinc
and nano-copper on guava trees unequivocally en-
hanced fruit quality compared to untreated trees.
The combination of both nano-zinc and nano-copper at
concentrations of 60 ppm and 30 ppm, respectively,
resulted in notably higher levels of non-reducing sugars
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Lakshya et al. / J. Appl. & Nat. Sci. 16(1), 239 - 244 (2024)
(3.32%), total sugars (8.74%), vitamin C (268.90
mg/100 g fruit), and reducing sugars (5.46%) (Table 1).
These findings align with the results obtained by Maha-
veer and Sangma, (2017) in their study on sweet or-
anges application of zinc sulphate 0.75% found in their
findings.
The zinc plays a pivotal role in oxidation-reduction re-
actions and catalyzes sugar metabolism, affecting the
quantities of total sugars, reducing sugars, and non-
reducing sugars in treated plants. This is attributed to
zinc's involvement in nucleic acid and starch metabo-
lism and its influence on various enzymes engaged in
these biochemical processes. Additionally, copper,
which was applied alongside zinc, demonstrated a pos-
itive correlation with the soluble solids content and total
sugars in guava fruits, consistent with findings in toma-
to fruits with a concentration of 10 mg Cu NPs, as Her-
nández et al., (2017) mentioned.
The study sheds light on the potential absorption mech-
anisms of nanoparticles (NPs) by plants. It is suggested
that the penetration of NPs through stomata on the leaf
surface plays a vital role in their absorption. NPs, due
to their small size, can interact with membrane
transport proteins and gain entry into plant cells, im-
pacting plant physiology at very low concentration
thresholds. Newly formed leaves are particularly effi-
cient at nutrient absorption due to their thinner wax lay-
er and relatively undeveloped nature (Ilyas et al.,
2015).
Studies have also revealed the effect of NPs on the
vascular tissues, epidermis, and mesophyll of leaves
(Manjunatha et al., 2016). They can even migrate from
the foliage to other plant parts, such as roots and re-
cently formed leaves. The entry of NPs into plant cells
can occur through various mechanisms, including ion
channels, endocytosis, or water molecular pathways. It
may trigger redox and other processes that alter the
morphology of NPs. Some foliar NPs can even create
new entry points in the plant cell walls to facilitate their
entry into cells. These findings correlate well with the
results of Bisma et al. (2020), who provide valuable
insights into the interactions and absorption of NPs in
plant systems.
Changes in Biochemical properties of fruit
In horticultural research, the influence of foliar applica-
tion of nano-zinc (nano-Zn) and nano-copper (nano-Cu)
on guava fruit quality emerged as a compelling subject.
The findings revealed a marked improvement in the
quality of guava fruits when nano-Zn and nano-Cu were
applied through foliar application, both separately and
in combination. Importantly, plants that were not treated
produced smaller and lighter fruits by comparison. This
robust improvement in fruit quality was corroborated by
various analytical data in Table 1.
In particular, combining nano-Zn and nano-Cu at con-
centrations of 60 ppm and 30 ppm resulted in a note-
worthy increase in various parameters. Non-reducing
sugars, an indicator of fruit sweetness, surged to
3.32%, while total sugars, encompassing both reducing
and non-reducing sugars, reached 8.74%. The ascorbic
acid content, a pivotal factor in fruit nutrition, soared to
268.90 mg/100 g of fruit, signifying a substantial en-
hancement in the fruit's health-promoting attributes
(Sachin et al. 2019). Additionally, reducing sugars, an
essential contributor to sweetness and flavor, escalated
to 5.46%. The present results correlate well with the
findings of Mahaveer and Sangma (2017), who ob-
served similar positive outcomes in sweet oranges.
Exploration into the underlying mechanisms revealed
that nano-Zn plays a central role in oxidation-reduction
reactions and serves as a catalyst in sugar metabolism.
This participation in sugar metabolism influences the
quantities of total sugars, reducing sugars, and non-
reducing sugars in treated plants. Zinc's influence ex-
tends to nucleic acid and starch metabolism, affecting
various enzymes in these biochemical processes. In
parallel, copper, applied alongside zinc, demonstrated a
positive correlation with soluble solids content and total
sugars in guava fruits, aligning with findings in tomato
fruits as reported by (Hipólito et al. (2019).
The study also delves into the fascinating world of na-
noparticles (NPs) and their potential absorption mecha-
nisms in plants. It is proposed that NPs primarily pene-
trate the plant through stomata on the leaf surface.
Their small size allows them to interact with membrane
transport proteins, gaining entry into plant cells and
affecting plant physiology even at very low concentra-
tions. Newly formed leaves, characterized by a thinner
wax layer and relative biological underdevelopment,
exhibit heightened efficiency in nutrient absorption
(Singh et al., 2023).
Moreover, research suggests that NPs can traverse
vascular tissues, epidermis, and mesophyll in leaves
exposed to NPs. These NPs are not confined to the
foliage but can migrate to other plant parts, including
roots and recently formed leaves. The mechanisms of
NP entry into plant cells encompass ion channels, en-
docytosis, and water molecular pathways, potentially
initiating redox reactions and other processes that im-
pact NP morphology. Remarkably, some foliar NPs can
even create novel entry points in plant cell walls to facil-
itate their entry into cells (Rajkumar, 2014).
The present findings offer valuable insights into the
transformative effects of nano-Zn and nano-Cu on gua-
va fruit quality, coupled with a deeper understanding of
how NPs interact with and are absorbed by plants. The
potential for enhancing fruit quality through nano-based
applications represents an exciting frontier in horticul-
tural science.
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Lakshya et al. / J. Appl. & Nat. Sci. 16(1), 239 - 244 (2024)
Conclusion
In the present study, different nanoparticles, including
Zn and Cu, were used to fabricate the Zn-Cu nanocom-
posite with smaller particle sizes. These smaller parti-
cles confirmed the composite's open network structure,
which helped in the easy migration of nano foliar spray
into the fruit body and maintains the biochemical prop-
erties of guava cv. Allahabad Safeda. At particular con-
centrations, the nano foliar spray showed significant
influence on various parameters, including total soluble
solids (TSS), titratable acidity, ascorbic acid content,
antioxidants, firmness, pectin content, total sugars, re-
ducing sugars, and non-reducing sugars. The results
revealed an increase in total sugar content of 8.74 %,
from which the part of non-reducing and reducing sugar
was 3.32 and 5.46 %, respectively, which are the indi-
cators of fruit sweetness. In addition, the ascorbic acid
content reached 268.90 mg/ 100g of fruit. The nano-Zn
played a vital role as a catalyst in the biochemical pro-
cesses of fruit for their oxidation-reduction reaction in
the sugar metabolism of treated plants. This study also
concludes the mechanism of NPs on the absorption
process in plants. Due to the smaller size of NPs, they
interact with membrane transport proteins and then
enter by different pathways like ion channels, endocyto-
sis, and water molecules into plant cells, impacting
plant physiology at a very low concentration. Thus,
these findings offer valuable insights into the transform-
ative effects of nano-Zn and nano-Cu to sustain the
guava fruit quality, coupled with a deeper understand-
ing of how NPs interact with and are absorbed by
plants. Therefore, this research could be scaled up as
an effective system to improve fruit quality and also
opens up an exciting frontier in horticultural science
with the application of nanotechnology in agriculture.
Conflict of interest
The authors declare that they have no conflict of
interest.
REFERENCES
1. Adisa, I. O., Pullagurala, V. L. R., Peralta-Videa, J. R.,
Dimkpa, C. O., Elmer, W. H., Gardea-Torresdey, J. L. &
White, J. C. (2019). Recent advances in nano-enabled
fertilizers and pesticides: a critical review of mechanisms
of action. Environmental Science. Nano, 6(7), 2002–2030.
https://doi.org/10.1039/c9en00265k
2. Anand, V., Arumugam, S., Rengasamy Lakshminara-
yanan Rengarajan, P. & Sampathkumar, R. (2020). Bioac-
tive compounds of guava (Psidium guajava L.). In Bioac-
tive Compounds in Underutilized Fruits and Nuts, page
503–527.
3. Baweja, P., Kumar, S. & Kumar, G. (2020). Fertilizers and
pesticides: Their impact on soil health and environment. In
Soil Biology (265–285). https://doi.org/10.1007/978-3-030-
Treatments Total
sugar
(%)
Reducing
sugars (%)
Non-
Reducing
sugars (%)
Vit C (mg/100
g fruit)
Pectin
content
(%) TSS (0B) Titratable
Acidity (%) TSS: TA
ratio Antioxi-
dants (%) Firmness
(kg/cm2)
Control (T1) 8.12a 4.95a 3.06a 246.14a 1.47a 9.68a 1.23f 7.82a 7.28a 5.00a
nano-Zn1 (T2) 8.20b 5.03b 3.12b 252.32b 1.57ab 9.75bc 1.23ef 7.93ab 7.39cd 5.17a
nano-Zn2 (T3) 8.24bc 5.08c 3.16bc 251.89b 1.60b 9.72ab 1.22ef 7.95ab 7.41de 5.31a
nano-Cu1 (T4) 8.25bc 5.12d 3.17bc 253.17b 1.65b 9.77bcd 1.20e 8.09b 7.3ab 5.38a
nano-Cu2 (T5) 8.35d 5.19e 3.22de 259.12c 1.78cd 9.84efg 1.17d 8.38c 7.37c 5.49a
nano-Zn1+nano-Cu1 (T6) 8.26c 5.15d 3.2cd 257.22c 1.68bc 9.79cde 1.20e 8.13b 7.32b 5.39a
nano-Zn1+nano-Cu2 (T7) 8.47e 5.20e 3.25ef 264.13d 1.81d 9.87fg 1.15d 8.53c 7.42de 5.52a
nano-Zn2+nano-Cu1 (T8) 8.64g 5.34f 3.29gh 258.46c 1.96e 9.82def 1.07b 9.17e 7.46fg 5.71a
Nano-Zn2+nano-Cu2 (T9) 8.74h 5.46h 3.32h 268.90e 2.13f 9.89g 0.98a 10.06f 7.49g 5.71a
ZnSo4 (T10) 8.54f 5.26f 3.27fg 263.51d 1.89de 9.85fg 1.12c 8.80d 7.44ef 5.59a
S.Em(±) 0.017 0.01 0.015 0.998 0.039 0.02 0.009 0.077 0.012 N/A
C.D.@5% 0.05 0.031 0.045 2.99 0.116 0.06 0.026 0.232 0.036 0.202
Table 1. Impact of nano-micronutrient (Zinc and Copper) on some biochemical parameters in guava fruit (Allahabad safeda)
244
Lakshya et al. / J. Appl. & Nat. Sci. 16(1), 239 - 244 (2024)
44364-1_15
4. Bisma, T., Bilal Pirzadah, A. & Jan, K. R. (2020). Nanofer-
tilizers: a way forward for green economy. Nanobiotech-
nology in Agriculture: An Approach Towards Sustainabil-
ity, 99–112.
5. Chandrakala, V., Aruna, V. & Angajala, G. (2022). Review
on metal nanoparticles as nanocarriers: current challeng-
es and perspectives in drug delivery systems. Emergent
Materials, 5(6), 1593–1615. https://doi.org/10.1007/
s42247-021-00335-x
6. Chen, Z., Bertin, R. & Froldi, G. (2013). EC50 estimation
of antioxidant activity in DPPH· assay using several statis-
tical programs. Food Chemistry, 138(1), 414–420. https://
doi.org/10.1016/j.foodchem.2012.11.001
7. Fao, W. (2009). Principles and methods for the risk as-
sessment of chemicals in food. Environmental Health
Criteria, 240.
8. Fatima, F., Hashim, A. & Anees, S. (2021). Efficacy of
nanoparticles as nanofertilizer production: a review. Envi-
ronmental Science and Pollution Research International,
28(2), 1292–1303. https://doi.org/10.1007/s11356-020-
11218-9
9. Francis, D. V., Sood, N. & Gokhale, T. (2022). Biogenic
CuO and ZnO nanoparticles as nanofertilizers for sustain-
able growth of Amaranthus hybridus. Plants, 11(20), 2776.
https://doi.org/10.3390/plants11202776
10. Hernández, H., Hernández, A., Benavides-Mendoza, H.,
Ortega-Ortiz, A. D. & Hernández-Fuentes, A. (2017). Cu
Nanoparticles in chitosan-PVA hydrogels as promoters of
growth, productivity and fruit quality in tomato. Emirates
Journal of Food and Agriculture, 29(8), 573–580.
11. Hipólito, T., Quiterio-Gutiérrez, G., Cadenas-Pliego, H.,
Ortega-Ortiz, A. D., Hernández-Fuentes, M., Cabrera De
La Fuente, J. & Valdés-Reyna, A. (2019). Impact of sele-
nium and copper nanoparticles on yield, antioxidant sys-
tem, and fruit quality of tomato plants. Plants, 8.
12. Hussain, S., Zameer, B., Naseer, T., Qadri, T. & Fatima,
T. A. (2021). Guava (Psidium Guajava)-Morphology, Tax-
onomy, Composition and Health Benefits. In Fruits Grown
in Highland Regions of the Himalayas: Nutritional and
Health Benefits (page 257–267).
13. Ilyas, A., Ashraf, M. Y., Hussain, M., Ashraf, M., Ahmed,
R. & Kamal, A. (2015). Effect of micronutrients (Zn, Cu
and B) on photosynthetic and fruit yield attributes of Citrus
reticulata Blanco var. kinnow. Pak. J. Bot, 47(4), 1241–
1247.
14. Iqbal, M. (2019). Nano-fertilizers for sustainable crop pro-
duction under changing climate: a global perspective.
Sustainable Crop Production, 8, 1–13.
15. Kumar, A., Mishra, A. K., Saroj, S. & Joshi, P. K. (2019).
Impact of traditional versus modern dairy value chains on
food security: Evidence from India’s dairy sector. Food
Policy, 83, 260–270. https://doi.org/10.1016/
j.foodpol.2019.01.010
16. Mahaveer, P. D. & Sangma, D. (2017). Role of micronutri-
ents (fe). Int. J. Curr. Microbiol. App. Sci, 6(6), 3240–
3250.
17. Mali, D. S., Sonavane, P. N., Handal, B. B. & Ranpise, S.
A. (2023). Assessment of harvesting index by adapting
different pruning levels in guava (Psidium guajava L.) Cv.
Sardar. The Pharma Innovation Journal, 12(6), 1095-1098
18. Manjunatha, S. B., Biradar, D. P. & Aladakatti, Y. R.
(2016). Nanotechnology and its applications in agriculture:
A review. J Farm Sci, 29(1), 1–13.
19. Mokdad, A. H., Forouzanfar, M. H., Daoud, F., Mokdad, A.
A., El Bcheraoui, C., Moradi-Lakeh, M., Kyu, H. H., Bar-
ber, R. M., Wagner, J., Cercy, K., Kravitz, H., Coggeshall,
M., Chew, A., O’Rourke, K. F., Steiner, C., Tuffaha, M.,
Charara, R., Al-Ghamdi, E. A., Adi, Y., Murray, C. J. L.
(2016). Global burden of diseases, injuries, and risk fac-
tors for young people’s health during 1990-2013: a sys-
tematic analysis for the Global Burden of Disease Study
2013. Lancet, 387(10036), 2383–2401. https://
doi.org/10.1016/S0140-6736(16)00648-6
20. Qureshi, A., Singh, D. K. & Dwivedi, S. (2018). Nano-
fertilizers: A novel way for enhancing nutrient use efficien-
cy and crop productivity. International Journal of Current
Microbiology and Applied Sciences, 7(2), 3325–3335.
https://doi.org/10.20546/ijcmas.2018.702.398
21. Rajkumar, J. T. (2014). Effect of foliar application of zinc
and boron on fruit yield and quality of winter season Gua-
va (Psidium guajava) cv. Pant Parbhat. Annals of Agri-Bio
Research, 19(1), 105–108.
22. Rana, R., Siddiqui, M., Skalicky, M., Brestic, M., Hossain,
A., Kayesh, E., Popov, M., Hejnak, V., Gupta, D.,
Mahmud, N. & Islam, T. (2021). Prospects of nanotechnol-
ogy in improving the productivity and quality of horticultur-
al crops. Horticulturae, 7(10), 332. https://doi.org/10.3390/
horticulturae7100332
23. Ranganna, S. (1977). Manual of analysis fruits and vege-
tables. Fruit and Vegetable Products (page 1–3).
24. Ranganna, S. (1986). Handbook of analysis and quality
control for fruit and vegetable products. Tata McGraw-Hill
Education. 2Rev Ed edition.
25. Singh, A., Kumar, R., Pal, G., Abrol, S., Punetha, P., &
Sharma, A. K. (2019). Nutritional and medicinal value of
underutilized fruits. Acta Scientific Agriculture, 3(1), 16–22.
26. Singh, S., Nand, N., Singh, G. & Bains, O. (2023). Effect
of foliar application of zinc oxide nanoparticles on bio-
chemical characteristics of guava (Psidium guajava L.) cv.
VNR Bihi. The Pharma Innovation Journal, 12(9), 575-577
27. Solanki, P., Bhargava, A., Chhipa, H., Jain, N. & Panwar,
J. (2015). Nano-fertilizers and their smart delivery system.
In Nanotechnologies in Food and Agriculture (page 81–
101). https://doi.org/10.1007/978-3-319-14024-7_4
28. Yadav, R. K. (2014). Impact of micronutrients on fruit set
and fruit drop of winter season guava (Psidium guajava L.)
cv. Allahabad safeda. Indian Journal of Science and Tech-
nology, 7(9), 1451–1453. https://doi.org/10.17485/
ijst/2014/v7i9.30
29. Zulfiqar, F., Navarro, M., Ashraf, M., Akram, N. A. & Mun-
né-Bosch, S. (2019). Nanofertilizer use for sustainable
agriculture: Advantages and limitations. Plant Science: An
International Journal of Experimental Plant Biology, 289
(110270), 110270. https://doi.org/10.1016/j.plantsci.20
19.110270
