Description:FIELD OF THE INVENTION
The present invention relates to the field of nanotechnology, green chemistry, and biomedical applications. More particularly, the invention pertains to an eco-friendly method for the synthesis of zinc oxide nanoparticles using Beta vulgaris (beetroot) peel extract as a reducing and stabilizing agent. The invention further relates to the utilization of the synthesized nanoparticles for antioxidant and antibacterial applications.
BACKGROUND OF THE INVENTION
References which are cited in the present disclosure are not necessarily prior art and therefore their citation does not constitute an admission that such references are prior art in any jurisdiction. All publications, patents and patent applications herein are incorporated by reference to the same extent as if each individual or patent application was specifically and individually indicated to be incorporated by reference.
Conventional methods of synthesizing zinc oxide nanoparticles involve toxic chemicals, high energy consumption, and costly reagents, posing environmental and health hazards. This invention proposes an ecofriendly, sustainable, and low-cost method using beetroot peel extract, a common food waste, to synthesize ZnO nanoparticles. The process adds value to agro-waste and contributes to clean nanotechnology development.
A novel nanomaterial synthesis technique using Beta vulgaris (beetroot) peel extract is revolutionizing the field of green nanotechnology. The increasing demand for safer, sustainable, and ecofriendly methods to synthesize nanoparticles has highlighted the limitations of conventional physical and chemical synthesis routes, which often involve toxic reagents, high energy consumption, and complex procedures. The green synthesis method proposed here addresses these issues effectively by utilizing Beta vulgaris peel, an agro-industrial waste product, as a natural reducing and stabilizing agent.
Beetroot peels are naturally rich in phytochemicals, including flavonoids, betalains, phenolic compounds, and ascorbic acid, which can reduce zinc ions to form zinc oxide (ZnO) nanoparticles under controlled conditions. These biomolecules also act as capping agents, preventing aggregation and stabilizing the nanoparticle structure. This environmentally friendly process does not require any hazardous chemicals and can be carried out at moderate temperatures, making it a cost-effective and scalable option for industrial applications.
The dried beetroot peel powder is mixed with distilled water and gently heated to extract the bioactive compounds. This extract is then combined with a zinc acetate solution and continuously stirred at 50–60°C. A visible color change from reddish-purple to off-white indicates the formation of nanoparticles. The reaction product is centrifuged and then calcined at 450°C to yield pure ZnO nanoparticles. The simplicity of this process enables low-cost production with minimal waste generation.
Various characterization techniques confirm the successful synthesis of ZnO nanoparticles:
UV-Visible spectroscopy shows absorption peaks in the 340–360 nm range, confirming nanoparticle formation.
FTIR analysis identifies Zn–O stretching vibrations and the presence of phytochemicals, validating the role of beetroot peel in the synthesis.
Scanning Electron Microscopy (SEM) reveals flower-like clusters of nanoparticles, indicating unique morphology.
Moisture content and titratable acidity tests confirm the stability and low residual moisture of the final product, ensuring good shelf life.
These green-synthesized ZnO nanoparticles exhibit significant biological activity. They demonstrate potent antioxidant properties, as shown through DPPH radical scavenging assays, and notable antibacterial activity against common pathogens such as E. coli, Klebsiella, Pseudomonas, and Streptococcus.
This green synthesis method not only addresses the global need for sustainable nanomaterials but also promotes the valorization of agricultural waste. The conversion of beetroot peel into high-value ZnO nanoparticles creates a circular economy model that supports environmental conservation while offering practical applications in the fields of food preservation, pharmaceuticals, cosmetics, and biomedical engineering.
Thus, the present invention offers an innovative, eco-conscious alternative to traditional nanoparticle synthesis, combining waste management with advanced material science to generate multifunctional, biocompatible nanomaterials.
Several patents zinc oxide but none of these are related to the present invention. Patent US9428399B1 relates a green synthesis method for producing nanoparticles of metals and metal oxides using Trigonella foenum-graecum (fenugreek) seed extract. The method involves mixing metal salt solutions with plant seed extract under controlled conditions, resulting in nanoparticle formation. The synthesized particles show antimicrobial activity.
Another patent US10703641B1 relates to A method for synthesizing metal nanoparticles can include combining a metallic nitrate with an extract of Kalanchoe blossfeldiana to form the metal nanoparticles. The method can include adding an aqueous solution of silver nitrate (AgNO3) to the extract of Kalanchoe blossfeldiana to form silver nanoparticles. The method can include dissolving zinc nitrate hexahydrate (Zn(NO3)2.6H2O) in an extract of Kalanchoe blossfeldiana to provide a zinc nitrate extract solution, stirring the zinc nitrate extract solution, and adding an aqueous solution of sodium hydroxide (NaOH) to the zinc nitrate extract solution to form zinc oxide nanoparticles.
Another patent US8057682B2 relates to methods of making and using and compositions of metal nanoparticles formed by green chemistry synthetic techniques. For example, the present invention relates to metal nanoparticles formed with solutions of plant extracts and use of these metal nanoparticles in removing contaminants from soil and groundwater and other contaminated sites. In some embodiments, the invention comprises methods of making and using compositions of metal nanoparticles formed using green chemistry techniques.
Another patent KR20220117942A belongs to novel pomegranate-zinc oxide nanocomposite particles and a use thereof. More specifically, the pomegranate-zinc oxide nanocomposite particles (PE-ZnO NPs) are novel zinc oxide nanocomposites in which polyphenols or flavonoids present in pomegranate extracts and zinc oxide (ZnO) are combined. The pomegranate-zinc oxide nanocomposite particles are less toxic to human skin cells than pomegranate extract and zinc oxide, has significantly increased antioxidant functionality, and has an antibacterial effect that inhibits the growth of microorganisms. Therefore, the novel pomegranate-zinc oxide nanocomposite particles, according to the present invention, are used as composite for foods or composition for cosmetics such as bioavailable preservatives for food, preservatives in cosmetics, supplements for health functional foods, sunscreen in cosmetics, and shampoo for improving scalp health. The pomegranate-zinc oxide nanocomposite particles can be used to control microorganisms that cause plant diseases by being included in agricultural chemicals for crops and flowers.
Another patent KR101675514B1 provides an antimicrobial agent containing zinc oxide nanoparticle aggregates as an active ingredient, and more particularly, to an antimicrobial agent comprising zinc oxide nanoparticles aggregates in various forms, The branch relates to antimicrobial agents. According to the present invention, it is known that it has good thermal stability such as not causing volatilization or decomposition, is used as a drug delivery vehicle, cosmetics, has no human toxicity, is low in price and has high antibacterial activity against Gram- By providing zinc oxide having various advantages in various forms and providing an antibacterial agent containing zinc oxide nanoparticles and their aggregates, it is possible to exhibit excellent antibacterial activity under dark room conditions and UV light irradiation.
OBJECTS OF THE INVENTION
Main object of the present invention is to ecofriendly synthesis of zinc oxide nanoparticles using beta vulgaris peel extract for antioxidant and antibacterial applications.
Another object of the present invention is to provide an eco-friendly, cost-effective, and sustainable method for the synthesis of zinc oxide nanoparticles using Beta vulgaris (beetroot) peel extract as a natural reducing and stabilizing agent.
Another object of the present invention is to eliminate the use of toxic chemicals and hazardous reducing agents generally employed in conventional nanoparticle synthesis, thereby reducing environmental impact.
Another object of the present invention is to utilize agro-waste, particularly Beta vulgaris peel, for the value-added production of zinc oxide nanoparticles, promoting waste valorization and circular bioeconomy.
Another object of the present invention is to develop zinc oxide nanoparticles with potent antioxidant and antibacterial activities suitable for applications in food preservation, pharmaceuticals, and biomedical formulations.
SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention.
This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings.
The present invention provides an eco-friendly and sustainable method for the synthesis of zinc oxide nanoparticles using Beta vulgaris (beetroot) peel extract as a reducing and stabilizing agent. The process employs the phytochemicals present in beetroot peels, such as phenolics, flavonoids, and betalains, to facilitate the reduction of zinc precursors into stable zinc oxide nanoparticles under controlled conditions. This approach eliminates the need for toxic chemicals and harsh reaction environments typically used in conventional nanoparticle synthesis, thereby offering a green alternative that is both economical and environmentally safe.
The invention further discloses the antioxidant and antibacterial activities of the synthesized zinc oxide nanoparticles, demonstrating their potential application in biomedical, pharmaceutical, food preservation, and environmental fields. The method not only provides a cost-effective synthesis route but also promotes the valorization of agricultural waste, thereby contributing to sustainable development and circular economy practices.
Herein enclosed a method for the eco-friendly synthesis of zinc oxide nanoparticles, comprising the steps of:
collecting fresh Beta vulgaris (beetroot) peels;
washing said peels to remove dirt and impurities;
drying the peels in a tray dryer at a temperature of 50–60°C for 5–6 hours;
grinding the dried peels into fine powder;
mixing the powder with distilled water and stirring at 50–60°C for about 30 minutes to obtain an extract;
filtering the extract to remove solid residues;
mixing the extract with an aqueous solution of zinc acetate dihydrate;
stirring the mixture on a magnetic stirrer at about 50°C until a color change from reddish-purple to off-white is observed;
centrifuging the mixture to separate the precipitate;
calcining the precipitate in a muffle furnace at 450°C for about 3 hours;
thereby obtaining zinc oxide nanoparticles.
The drying of the beetroot peels is carried out in a tray dryer at 50–60°C for a period of 5 to 6 hours to ensure complete removal of moisture.
The mixing of beetroot peel powder with distilled water and stirring at 50–60°C for 30 minutes facilitates the extraction of phytochemicals including flavonoids, phenolics, and betalains.
The observable color change from reddish-purple to off-white serves as a visual indicator of zinc oxide nanoparticle formation.
Calcination of the precipitate at 450°C for 3 hours results in the formation of pure and crystalline zinc oxide nanoparticles exhibiting antioxidant and antibacterial activity.
BRIEF DESCRIPTION OF THE DRAWINGS
The illustrated embodiments of the subject matter will be understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
Fig. 1 Picture of ZnO nanoparticle powder
DETAILED DESCRIPTION OF THE INVENTION
The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
In addition, the descriptions of "first", "second", “third”, and the like in the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In some embodiments of the present invention, the present invention relates to an eco-friendly method for the synthesis of zinc oxide nanoparticles using Beta vulgaris (beetroot) peel extract as a natural reducing and stabilizing agent.
In some embodiments of the present invention, fresh beetroot peels are collected, washed thoroughly to remove dirt and impurities, and dried in a tray dryer at 50–60°C for 5–6 hours, after which the dried peels are ground into a fine powder.
In some embodiments of the present invention, the powder is mixed with distilled water and stirred at 50–60°C for 30 minutes to release bioactive phytochemicals, and the mixture is then filtered to obtain a clear extract.
In some embodiments of the present invention, this extract is combined with an aqueous solution of zinc acetate dihydrate and subjected to magnetic stirring at 50°C, during which a visible color change from reddish-purple to off-white indicates nanoparticle formation. The resulting mixture is centrifuged to separate the precipitate, which is then washed, dried, and calcined in a muffle furnace at 450°C for 3 hours to obtain pure zinc oxide nanoparticles.
In some embodiments of the present invention, the synthesized nanoparticles possess desirable properties including antioxidant and antibacterial activity, making them suitable for use in pharmaceuticals, biomedical applications, food preservation, and environmental protection.
Herein enclosed a method for the eco-friendly synthesis of zinc oxide nanoparticles, comprising the steps of:
collecting fresh Beta vulgaris (beetroot) peels;
washing said peels to remove dirt and impurities;
drying the peels in a tray dryer at a temperature of 50–60°C for 5–6 hours;
grinding the dried peels into fine powder;
mixing the powder with distilled water and stirring at 50–60°C for about 30 minutes to obtain an extract;
filtering the extract to remove solid residues;
mixing the extract with an aqueous solution of zinc acetate dihydrate;
stirring the mixture on a magnetic stirrer at about 50°C until a color change from reddish-purple to off-white is observed;
centrifuging the mixture to separate the precipitate;
calcining the precipitate in a muffle furnace at 450°C for about 3 hours;
thereby obtaining zinc oxide nanoparticles.
The drying of the beetroot peels is carried out in a tray dryer at 50–60°C for a period of 5 to 6 hours to ensure complete removal of moisture.
The mixing of beetroot peel powder with distilled water and stirring at 50–60°C for 30 minutes facilitates the extraction of phytochemicals including flavonoids, phenolics, and betalains.
The observable color change from reddish-purple to off-white serves as a visual indicator of zinc oxide nanoparticle formation.
Calcination of the precipitate at 450°C for 3 hours results in the formation of pure and crystalline zinc oxide nanoparticles exhibiting antioxidant and antibacterial activity.
EXAMPLE 1
Materials and Methods
Preparation Steps :
The present invention provides a green synthesis method for zinc oxide nanoparticles utilizing Beta vulgaris (beetroot) peel extract as a reducing and stabilizing agent. The process begins with the collection of fresh beetroot peels, which are thoroughly washed with distilled water to remove dirt and impurities. The cleaned peels are then subjected to drying in a tray dryer at a temperature range of 50–60°C for 5–6 hours to remove residual moisture. The dried peels are subsequently ground into a fine powder using a mechanical grinder.
The powdered peel material is mixed with distilled water and subjected to continuous stirring at 50–60°C for approximately 30 minutes to obtain a crude extract containing bioactive phytochemicals such as flavonoids, phenolics, and betalains. The mixture is filtered to obtain a clear aqueous extract, which serves as the reducing and stabilizing medium.
For nanoparticle synthesis, the beetroot peel extract is mixed with an aqueous solution of zinc acetate dihydrate under controlled conditions. The mixture is stirred on a magnetic stirrer at approximately 50°C, during which a noticeable color change occurs from reddish-purple to off-white, indicating the initiation of zinc oxide nanoparticle formation. The resulting colloidal suspension is centrifuged to separate the precipitate, followed by thorough washing to remove unreacted residues.
The obtained precipitate is dried and subsequently calcined in a muffle furnace at 450°C for 3 hours, leading to the formation of pure, crystalline zinc oxide nanoparticles (ZnO NPs). The nanoparticles thus produced exhibit significant antioxidant and antibacterial activities, making them suitable for applications in biomedical, pharmaceutical, food packaging, and environmental remediation sectors.
Collection of Fresh Beetroot Peels
↓
Washing to Remove Dirt & Impurities
↓
Drying in Tray Dryer (50–60°C for 5–6 hours)
↓
Grinding into Fine Powder
↓
Mixing Powder with Distilled Water
(Stirring at 50–60°C for 30 minutes)
↓
Filtration of Extract
↓
Mixing Extract with Zinc Acetate Dihydrate Solution
↓
Stirring on Magnetic Stirrer at 50°C
↓
Observation of Color Change (Reddish-purple to Off-white)
↓
Centrifugation to Separate Precipitate
↓
Calcination in Muffle Furnace (450°C for 3 hours)
↓
Formation of Zinc Oxide Nanoparticles (ZnO NPs)
Example 2
Experimental data:
• UV-Vis Absorption: Characteristic absorption peak observed between 340–360 nm, confirming ZnO nanoparticle formation.
• FTIR Analysis: Peaks between 400–600 cm⁻¹ indicating Zn–O bond and presence of phytochemicals.
• SEM Analysis: Revealed flower-like clustered morphology of ZnO nanoparticles.
• Antioxidant Activity: Significant free radical scavenging observed through DPPH assay.
• Antibacterial Activity: Maximum zone of inhibition of 12 mm against Streptococcus confirmed strong antimicrobial property.
• Moisture Content: Low moisture retention indicating good stability and shelf life of the nanoparticles.
According to the results of the study examining the green synthesis of zinc oxide nanoparticles using Beta vulgaris peel extract, the nanoparticles exhibited promising physicochemical and biological properties. The UV-Visible spectroscopy confirmed nanoparticle formation through a strong absorption peak between 340–360 nm, while FTIR analysis revealed the presence of Zn–O bonds and residual phytochemicals, indicating successful green synthesis. SEM imaging showed well-defined flower-like clusters, suggesting a unique morphological structure. The synthesized nanoparticles demonstrated significant antioxidant activity via DPPH assay, highlighting their potential to neutralize free radicals. Additionally, antibacterial testing revealed a maximum inhibition zone of 12 mm against Streptococcus, confirming their strong antimicrobial effectiveness. The low moisture content observed in the final product indicates high stability and a long shelf life. These findings suggest that beetroot peel-mediated ZnO nanoparticles are a cost-effective, ecofriendly, and multifunctional nanomaterial with potential applications in health, food, and pharmaceutical sectors.
ADVANTAGES OF THE INVENTION:
Eco-Friendly and Sustainable: The synthesis process uses Beta vulgaris (beetroot) peel—a commonly discarded agro-waste—as a natural reducing and stabilizing agent, minimizing chemical usage and environmental impact.
Cost-Effective Production: The use of inexpensive and readily available plant waste significantly reduces production costs compared to conventional chemical and physical nanoparticle synthesis methods.
Non-Toxic and Safe: Unlike traditional methods that involve hazardous chemicals, this green synthesis route is non-toxic, making it suitable for applications in food packaging, cosmetics, and pharmaceuticals.
Enhanced Antibacterial Activity: The ZnO nanoparticles synthesized through this method demonstrate strong antimicrobial activity against multiple pathogenic bacteria (E. coli, Streptococcus, Klebsiella, Pseudomonas), making them suitable for use in antimicrobial coatings and formulations.
High Antioxidant Potential: The presence of residual phytochemicals from beetroot peel imparts strong antioxidant activity to the nanoparticles, adding functional value in biomedical and food preservation applications.
 
, Claims:1. A method for the eco-friendly synthesis of zinc oxide nanoparticles, comprising the steps of:
a) collecting fresh Beta vulgaris (beetroot) peels;
b) washing said peels to remove dirt and impurities;
c) drying the peels in a tray dryer at a temperature of 50–60°C for 5–6 hours;
d) grinding the dried peels into fine powder;
e) mixing the powder with distilled water and stirring at 50–60°C for about 30 minutes to obtain an extract;
f) filtering the extract to remove solid residues;
g) mixing the extract with an aqueous solution of zinc acetate dihydrate;
h) stirring the mixture on a magnetic stirrer at about 50°C until a color change from reddish-purple to off-white is observed;
i) centrifuging the mixture to separate the precipitate;
j) calcining the precipitate in a muffle furnace at 450°C for about 3 hours; and
k) thereby obtaining zinc oxide nanoparticles.
2. The method as claimed in claim 1, wherein the drying of the beetroot peels is carried out in a tray dryer at 50–60°C for a period of 5 to 6 hours to ensure complete removal of moisture.
3. The method as claimed in claim 1, wherein the mixing of beetroot peel powder with distilled water and stirring at 50–60°C for 30 minutes facilitates the extraction of phytochemicals including flavonoids, phenolics, and betalains.
4. The method as claimed in claim 1, wherein the observable color change from reddish-purple to off-white serves as a visual indicator of zinc oxide nanoparticle formation.
5. The method as claimed in claim 1, wherein calcination of the precipitate at 450°C for 3 hours results in the formation of pure and crystalline zinc oxide nanoparticles exhibiting antioxidant and antibacterial activity.