DESC:PLANT-BASED EDIBLE COATING FOR ENHANCING THE SHELF LIFE OF PERISHABLE PRODUCTS

FIELD OF INVENTION

[0001] The present disclosure described herein, in general, relates to an economical and sustainable food preservation system. In particular, the present disclosure relates to developing a plant-based edible coating for enhancing the shelf life of perishable products through recycling of the waste produced from food processing industries.

BACKGROUND OF THE INVENTION

[0002] India is a major producer of fruits and yielding vast amounts of pectin-rich wastes from fruits like pomegranates, mangoes, apples. Despite being a significant player in horticultural production, India also grapples with a comparable volume of horticultural waste, necessitating effective management. Notwithstanding its agricultural prominence, a concerning percentage of Indian farmers experience substantial post-harvest losses, which can amount to as high as 15% of the total produce.

[0003] With the growing demand for exotic and perishable food items globally and increasing environmental concerns regarding the long-term effects of existing preservation methods, the food industry has witnessed a surge in innovative technologies. One such avenue is the utilization of “active packaging”, which involves integrating “active compounds” into the polymer matrix to perform specific functions such as oxygen scavenging, ethylene absorption, and antimicrobial activity. Among the various additives used in conventional “packaging, essential oils stand out due to their dual characteristics of antioxidant and antimicrobial properties. Table 1 as provided below depicts the bio-polymers currently employed in food preservation.

Table 1: Current bio-polymers used in food preservation

[0004] Furthermore, a number of these bio-polymers have been successfully commercialized as viable alternatives for standard petroleum-based polymer packaging. Table 2 as provided below depicts some of the current packaging options available to the food industry.

Table 2: current commercial ventures in food packaging

[0005] As seen above in Table 2, a number of studies have been undertaken by different entities on the development of new and improved technologies for food preservation. However, several cold storage techniques possess limited applicability because they depend on a consistent energy source and/or coolant system for preservation. The types of food that can be preserved through these techniques is limited as many fruits and meat products are susceptible to “freezer burn”, a condition arising from contact with oxygenated air during freezing. The oxidation which occurs at this temperature results in a degradation of texture and nutritive value. Although alternative techniques like cold plasma demonstrate effectiveness, they are encumbered by high costs and energy demands, rendering them impractical for on-farm preservation of fresh produce.

[0006] Pectin is naturally derived from plant sources unlike animal sourced chitosan and is water soluble and easier to process as compared to cellulose or its various derivatives. Pectin is extracted from fruit and vegetable wastes, making it an excellent value-added product obtained by a waste to wealth approach. Thus, the cross-linked pectin films have the potential to be employed for advanced food packaging applications such as active packaging materials that can actively interact with the food product, such as releasing antimicrobial agents or antioxidants to enhance preservation and shelf life.

[0007] The chemical structure of pectin also serves as an advantage. The various carboxylic groups present on the monomeric units are excellent sites for functionalization with various compounds including anti-microbial moieties. Pectin has already been functionalized for use in cell delivery and related biomedical applications. Given that pectin is plant-based, it should also be biocompatible with other natural materials, including honey. Blends of pectin and Manuka honey have already been explored for wound healing purposes. Similarly, the incorporation of bismuth ions into the pectin has been previously explored for applications in the treatment of ulcers and helicobacter pylori. Thus, the functionalization of pectin monomers with anti-microbials such as bismuth compounds and co-mixing with natural anti-microbials such as Manuka honey to fabricate polymer films with an aim towards food preservation is an avenue worth investigating.

[0008] Thus, there remains a need in the art for the development of an efficient, sustainable, edible, environmentally safe and relatively economical plant based biopolymeric coating for enhancing shelf life of the perishable products. Biopolymer based technologies, thus provide an exciting alternative for the development of economical preservation technologies.

OBJECT OF THE INVENTION

[0009] The primary object of the present disclosure is to provide an efficient, sustainable, edible, environmentally safe and relatively economical plant based biopolymeric coating for enhancing shelf life of the perishable products through recycling of the waste produced from food processing industries.

[0010] Yet another object of the present disclosure is to provide a method for fabrication of a novel plant based biopolymeric coating produced by recycling of the waste produced from food processing industries for enhancing shelf life of the perishable products.

[0011] Yet another object of the present disclosure is to optimize the plant based biopolymeric coating and enhance its sustainability.

[0012] Yet another object of the present disclosure is to utilize.the plant based biopolymeric coating in the intelligent packaging systems that incorporate plurality of sensors for monitoring and detecting the signs of food spoilage.

SUMMARY OF THE INVENTION

[0013] In an aspect of the present disclosure, a novel plant based biopolymeric coating composition for enhancing shelf life of the perishable products through recycling of the waste produced from food processing industries has been disclosed.

[0014] In an aspect of the present disclosure, a method for enhancing the shelf life of the perishable products through a plant based biopolymeric coating composition produced by recycling of the waste produced from food processing industries has been disclosed. The plant based biopolymeric coating composition comprises a novel combination of antimicrobial active compounds.

[0015] In an aspect of the present disclosure, the plant based biopolymeric coating composition comprises a polymer solution comprising a plurality of hydrogels of pectin, a pre-defined amount of manuka honey and a pre-defined amount of bismuth (III) bromide. The plurality of hydrogels of pectin are fabricated by crosslinking a pre-determined ratio of pectin with atleast one bio-polymer in presence of a cross-linking agent. The pre-defined ratio of pectin with atleast one bio-polymer is in the range of 1:1 to 1:4.

[0016] In an aspect of the present disclosure, the pre-defined amount of manuka honey is in the range of 10% to 20% w/v of the polymer solution and the pre-defined amount of bismuth (III) bromide is in the range of 0 to 2.5% (w/v).

[0017] In an aspect of the present disclosure, the resulting crosslinked hydrogels of pectins (pectin films) are completely insoluble in water resulting from the unique crosslinked macromolecular structure of the pectin films.

[0018] In an aspect of the present disclosure, a method of synthesizing a plant-based biopolymeric coating composition for enhancing the shelf life of a perishable item has been disclosed. The method comprises the step of fabricating a polymer solution comprising a plurality of hydrogels of pectin by crosslinking a pre-defined ratio of pectin with at least one bio-polymer in presence of a cross-linking agent. Followed by adding a pre-defined amount of manuka honey and bismuth (III) bromide into the polymer solution comprising the plurality of hydrogels of pectins. The manuka honey and bismuth (III) bromide are potent and effective antimicrobials. Their addition to the polymer solution comprising the plurality of hydrogels of pectins (crosslinked films), enhances the antimicrobial activity of the plant based biopolymeric coating composition and the barrier properties of the biopolymeric coating composition.

[0019] In an aspect of the present disclosure, a product comprising a perishable item and a plant-based biopolymeric coating formed on the perishable item based on the plant-based biopolymeric coating composition is disclosed. The coating is formed on the perishable item by applying a layer of the plant-based biopolymeric coating composition by using atleast one of a coating application process.

[0020] These and other objects, features, and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description.

BRIEF DESCRIPTION OF DRAWINGS

[0021] The exemplary embodiments of the present invention have been described with reference to the accompanying drawings below:
[0022] Figure 1 illustrates the methodology for obtaining hydrogels of pectin (pectin films) in accordance with the prior art.
[0023] Figure 2 illustrates the methodology for fabricating hydrogels of pectin (pectin films) in accordance with the present invention.
[0024] Figure 3 illustrates graphical analysis of percentage solubility of tested polymer films in accordance with the present disclosure.
[0025] Figure 4 illustrates graphical analysis of load bearing capacity of tested polymer films in accordance with the present disclosure.
[0026] Figure 5 illustrates graphical analysis of thermogravimetric analysis of polymer films in accordance with the present disclosure.
[0027] Figure 6 illustrates the SEM image of the surface of pectin CMC polymer film.in accordance with the present disclosure.
[0028] Figure 7 illustrates the schematic of the crosslinked structure with predicted 13C NMR peak locations in accordance with the present disclosure.
[0029] Figure 8 illustrates the graphical analysis of solubility percentage of tested polymer films in accordance with the present disclosure.
[0030] Figure 9 illustrates swelling percentage of tested polymer films in accordance with the present disclosure.
[0031] Figure 10 illustrates the graphical analysis of vapour transmission rates for tested polymer films in accordance with the present disclosure.
[0032] Figure 11 illustrates the FT-IR analysis of the tested polymer films in accordance with the present disclosure.
[0033] Figure 12(a) to 12(b) illustrates the zone of inhibition observed in P. aeruginosa and S. aureus in accordance with the present disclosure.
[0034] Figure 13 illustrates the graphical analysis of antimicrobial activity of tested polymer films in accordance with the present disclosure.
[0035] Figure 14 illustrates the graphical analysis of optical density of E coli samples incubated with tested polymer films in accordance with the present disclosure.
[0036] Figure 15 illustrates the graphical analysis of optical density of S. aureus samples incubated tested polymer films in accordance with the present disclosure.
[0037] Figure 16 (a) to 16 (b) illustrates the comparative graphical analysis of percentage weight loss in uncoated samples and samples coated with the coating in accordance with the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0038] The invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation procedures are given, but the scope of protection of the present invention is not limited to the following embodiments.

[0039] In an embodiment of the present invention, aa plant based biopolymeric coating composition produced by recycling of the waste produced from food processing industries for enhancing shelf life of the perishable products has been disclosed. Further the present invention discloses an efficient, sustainable, edible, environmentally safe and relatively economical method for the synthesis of a plant based biopolymeric coating composition for enhancing shelf life of the perishable products.

[0040] In an embodiment of the present invention, the plant based biopolymeric coating composition comprises a polymer solution comprising a plurality of hydrogels of pectins, a pre-defined amount of manuka honey and a pre-defined amount of bismuth (III) bromide. The plurality of hydrogels of pectins are fabricated by crosslinking a pre-defined ratio of pectin with atleast one bio-polymer in presence of a cross-linking agent. The predefined ratio of pectin with atleast one bio-polymer is in the range of 1:1 to 1:4.

[0041] In an embodiment of the present invention, the pre-defined amount of manuka honey is in the range of 10% to 2% w/v of the polymer solution and the pre-defined amount of bismuth (III) bromide is in the range of 0 to 2.5% (w/v).

[0042] In an aspect of the present disclosure, the resulting crosslinked hydrogels of pectin (pectin films) are completely insoluble in water resulting from the unique crosslinked macromolecular structure of the pectin films.

[0043] In an embodiment of the present invention, the atleast one bio-polymer is selected from a group comprising of methyl cellulose, alginate and carboxy methyl cellulose.

[0044] In an embodiment of the present invention, the cross-linking agent is selected from group comprising of calcium chloride, citric acid, glutaraldehyde, ethyl di-glycidyl ether and Polyethylene glycol diglycidyl ether (PEGDE).

[0045] In an embodiment of the present invention, the biopolymeric coating composition is edible and exhibit less water solubility in the range of 0.5% to 8%.

[0046] In an embodiment of the present invention, the biopolymeric coating composition is anti-microbial in nature due to the presence of pre-defined amount of manuka honey and pre-defined amount of bismuth (III) bromide.

[0047] In an embodiment of the present invention, a product comprising a perishable item and a plant-based biopolymeric coating formed on the perishable item based on the plant-based biopolymeric coating composition is disclosed. The coating is formed on the perishable item by applying a layer of the plant-based biopolymeric coating composition by using atleast one of a coating application process. The coating application process is selected from dip-coating, spray-coating, spin coating, powder-coating, wrapping sealing, covering, layering or any combination thereof.

[0048] In an embodiment of the present invention, the layer of the plant-based biopolymeric coating composition has a thickness in the range of 0.1 to 0.2 mm.

[0049] In an embodiment of the present invention, the plant-based biopolymeric coating provides an oxygen permeability coefficient in the range of 25 to 100 cc m-2 .

[0050] In an embodiment of the present invention, the plant-based biopolymeric coating has a water diffusivity in the range of 0.5 to 3g/day/m2.

[0051] In an embodiment of the present invention, the plant-based biopolymeric coating exhibit less water- solubility in the range of 0.5 to 8%.

[0052] In an embodiment of the present invention, the perishable item is selected from a group comprising of fruits, vegetables, flowers, plants, meat, poultry, sea foods.

[0053] In an embodiment of the present disclosure, a method of synthesizing a plant-based biopolymeric coating composition for enhancing the shelf life of a perishable item has been disclosed. The method comprises the step of fabricating a polymer solution comprising a plurality of hydrogels of pectin by crosslinking a pre-defined ratio of pectin with at least one bio-polymer in presence of a cross-linking agent. Followed by adding a pre-defined amount of manuka honey and bismuth (III) bromide into the polymer solution comprising the plurality of hydrogels of pectins. The manuka honey and bismuth (III) bromide are potent and effective antimicrobials. Their addition to the polymer solution comprising the plurality of hydrogels of pectins (crosslinked films), enhances the antimicrobial activity of the plant based biopolymeric coating composition and the barrier properties of the biopolymeric coating composition.

[0054] Polymer solution comprising the plurality of hydrogels of pectins (pectin films) synthesized using this combination have novel physicochemical properties comprising water insolubility, enhanced elasticity and thermal stability which can be further tuned by altering the ratios of the polymers.

[0055] Further the plurality of hydrogels of pectins are incorporated with the combination of manuka honey and bismuth (III) bromide, the resulting plant-based biopolymeric coating composition show potent anti-microbial effect against common pathogens E. coli and S. aureus. Furthermore, the incorporation of predefined amount of manuka honey and predefined amount of bismuth (III) bromide into polymer solution comprising the plurality of hydrogels of pectins enhances the humectant and water barrier properties of the polymer solution. The plant-based biopolymeric coating composition is a prime candidate for applications in food preservation and prolonging the shelf life of perishable products. The applicability of the plant-based biopolymeric coating composition in food preservation is thus tested by immersing Indian plums in the polymeric solution and a significant reduction in both the decay rate and antimicrobial attack is observed.

[0056] Working Examples

[0057] The present invention is now further described by the following non-limiting examples.

[0058] Figure 1 illustrates the methodology for obtaining hydrogels of pectin (pectin films) in accordance with the prior art for the fabrication of pectin films by simply dissolving pectin in water resulting in a polymeric solution that is cast into a suitable mold and allowed to dry.

[0059] Figure 2 illustrates the method for fabrication of modified hydrogels of pectins (modified pectin films) in accordance with an embodiment of the present invention. The modified pectin films of the present invention were fabricated by crosslinking a pre-defined ratio of pectin with plurality of bio-polymers selected from a group comprising of methyl cellulose, alginate and carboxy methyl cellulose in presence of cross-linking agents selected from group comprising of calcium chloride, citric acid, glutaraldehyde, ethyl di-glycidyl ether and Polyethylene glycol diglycidyl ether (PEGDE) as depicted in Table 3 and Table 4 below.

Table 3: Screening of Cross-linkers

Table 4: Various polymers tested in conjugation with pectin with PEDGE as the crosslinker

[0060] Physiochemical properties of the hydrogels of pectin/pectin films:

[0061] In an embodiment of the present invention, the fabrication of hydrogels of pectins has been disclosed. The hydrogel of pectin is fabricated by crosslinking pectin and carboxymethyl cellulose (CMC) in ratio’s selected from group comprising of 1:1, 1:4 and 2:3 with polyethylene glycol diglycidyl ether as a cross-linking agent. The resulting hydrogel of pectin (pectin film) is characterized to study its physiochemical properties.

[0062] Figure 3 illustrates graphical analysis of percentage solubility of the hydrogels of pectin (pectin films) in accordance with the present disclosure. Figure 4 illustrates graphical analysis of load bearing capacity of the pectin films in accordance with the present disclosure. Figure 5 illustrates graphical analysis of thermogravimetric analysis of the pectin films in accordance with the present disclosure. The introduction of carboxymethyl cellulose (CMC) has a direct impact on the physiochemical properties of the plant-based biopolymeric coating composition. Figure 3 to figure 5 illustrates that concentration of CMC have a direct effect on the tensile strength, swelling capacity and water vapor permeability of the pectin films.

[0063] Figure 6 illustrates the SEM image of the surface of pectin CMC polymer film in accordance with the present disclosure. Figure 6 illustrates self-aggregation of the CMC molecules with the increasing concentration of CMC above a certain limit simultaneously resulting in the formation of void spaces throughout the hydrogels of pectin.

[0064] Further, the crosslinked hydrogels of pectin is completely insoluble in water despite their hydrophilicity resulting from the unique crosslinked macromolecular structure of the hydrogels of pectin as illustrated in Figure 7. The aforementioned properties of the hydrogels of pectin is attributed to a unique cross-linking mechanism between molecules of pectin, PEGDE and CMC. Figure 7 illustrates the schematic of the crosslinked structure with predicted 13C NMR peak locations in accordance with the present disclosure. Figure 7 illustrates the intermolecular cross-linked species that is in conformity with previous reports of the cross-linking mechanism between CMC and polyethylene glycol and PEGDE. However, the cross-linking that occurs with pectin, while similar is still relatively new and has yet to be fully explored. Further investigation into which of the four hydroxyl groups present on the galacturonic acid monomer of pectin are preferred for undergoing cross-linking with PEGDE is warranted.

[0065] Suitability of pectin-CMC crosslinked films in biomedical applications

[0066] Suitability of pectin-CMC crosslinked films in biomedical applications is evaluated with the incorporation of manuka honey, bismuth (III) bromide and a combination of both into the crosslinked films and release of manuka honey, bismuth (III) bromide over time in an aqueous medium is evaluated. The manuka honey and bismuth (III) bromide are potent and effective antimicrobials. Manuka honey is a specific variety of honey produced from the nectar of the Manuka tree by Apis mellifera bees. The manuka honey is procured from New Zealand. 20 mL of 50% (w/v) manuka honey/bismuth (III) bromide/ a combination of both solution in milli Q waster is added to 100 mL of 2% (w/v) polymer solution comprising a plurality of hydrogels of pectin fabricated by crosslinking pectin with CMC in a 1:1 ratio with PEGDE as a cross-linking agent. Post-crosslinking, the required amount of glycerol is added, and the solution is cast into petri dishes and dried overnight.

[0067] The polymer solution comprising plurality of hydrogels of pectins incorporated with manuka honey/bismuth (III) bromide or a combination of both manuka honey and bismuth (III) bromide is evaluated for characterizing its solubility percentage, swelling percentage, water vapor permeability and thermal stability in accordance with an embodiment of the present invention.

[0068] Figure 8 illustrates the graphical analysis of solubility percentage of various tested polymer films in accordance with the present disclosure. Figure 9 illustrates swelling percentage of various tested polymer films in accordance with the present disclosure. Figure 10 illustrates the graphical analysis of vapor transmission rates for various tested polymer films in accordance with the present disclosure. Figure 11 illustrates the FT-IR analysis of the various tested polymer films in accordance with the present disclosure.

[0069] Anti-Microbial Activity of the plant-based biopolymeric coating composition

[0070] The antimicrobial activities of the plant-biopolymeric coating composition comprising a polymeric solution comprising a plurality of hydrogels of pectin (pectin films) incorporated with Manuka honey and bismuth (III) bromide is evaluated by the disc diffusion method in agar against E. coli, Staphylococcus aureus and Pseudomonas aeruginosa. The preparation of the microorganisms for the test comprised the steps of reviving the Frozen colonies of E. coli and Pseudomonas by aseptically steaking petri plates of LB agar and subsequently incubating them at 37°C for 16 hours. Similarly, S. aureus is aseptically streaked in nutrient agar and subsequently incubated at 37°C for 16 h. Colonies of each microorganism is then selected and aseptically inoculated in to fresh LB broth for E. Coli and Pseudomonas and BHI broth for S. Aureus. Following incubation at 37°C for 16 h, 1 ml suspension containing 106 CFU/ml of each investigated microorganism is diluted in 3ml of corresponding broths and then spread on the surface of the specific agar medium. Following this step, 5mm discs of the pectin film is placed on top of the agar along with selected positive and negative control. Four separate films were tested vis. Pectin films without any antimicrobial actives, pectin films with manuka honey, pectin films incorporated with bismuth and pectin films incorporating both antimicrobial actives. All the test plates underwent inspection post incubating the plates for 24 hours at 37°C. The diameters of the inhibition zone is measured (in cm) with a ruler on the underside of the petri dish. After incubating the plates at 37°C for 24 hours, zones of inhibition is observed on the surface of the agar plates for all microbial strains as illustrated in figure 12 (a) to 12(b). Figure 12(a) to 12(b) illustrates the zone of inhibition observed in P. aeruginosa and S. aureus in accordance with the present disclosure. The diameter of the zones of inhibition is measured and used as a measure of the anti-microbial activity of the pectin films.

[0071] Figure 13 illustrates the graphical analysis of antimicrobial activity of the tested polymer films in accordance with the present disclosure. Figure 13 illustrates that the combination of Manuka honey and bismuth (III) bromide has significant antimicrobial effect on the growth of common bacterial strains. In contrast pectin in combination with CMC and PEGDE did not illustrate any inherent antimicrobial activity on its own. The antimicrobial effect varied with respect to the strain used with E coli showing the most significant response in presence of bismuth (III) bromide and manuka honey.

[0072] This combined synergistic effect is more evident when the above experiment is repeated using the optical density measurements of colonies of E. coli and S. aureus. The anti-microbial activity of the pectin films is further verified via the optical density measurements of E coli and S. aureus colonies when incubated for 24 hours and 48 hours in contact with the films. The absorbance of colonies incubated with various films at 600nm is illustrated in figures 14 and 15.

[0073] Figure 14 illustrates the graphical analysis of optical density of E coli samples incubated with the tested pectin films in accordance with the present disclosure. Figure 14 illustrates that the pectin films have significant inhibitory effect on the growth of E. coli colonies. Pectin films without any anti-microbial actives included seem to show a slight inhibition of bacterial colonies when compared to the negative control. The inclusion of Manuka honey on the other hand shows a significant anti-microbial effect in the inhibition of bacteria. This finding is in agreement with the results obtained by Giusto et al. who postulated the presence of methyl glyoxal and hydrogen peroxide in the honey led to the enhanced effect.

[0074] A similar effect is seen in the case of pectin films incorporated with bismuth (III) bromide where the presence of the Bi3+ ions upon reaching a critical concentration leads to inhibition of E coli strains as detailed by Subils et al. Perhaps the most surprising effect seen is the inhibitory effect caused by the films incorporating both honey and the bismuth salt where the presence of both actives leads to significantly reduced optical density, almost comparable to the positive control of 3mgs of ampicillin, a potent antibiotic. The inhibitory effect of all films increases marginally over a period of 24 to 48 hours as seen by the decrease in absorbance values.

[0075] Figure 15 illustrates the graphical analysis of optical density of S. aureus samples incubated the tested pectin films in accordance with the present disclosure. Figure 15 illustrates that the pectin films incubated with S. aureus colonies illustrates similar trend as illustrated in E. coli. Figure 15 illustrates that the inhibitory effect is less pronounced in the higher absorbance values.

[0076] Figure 15 illustrates that there is almost no inhibitory effect observed in case of pure crosslinked pectin films having an almost equal absorbance as the negative control after 24 hours. Films incorporating Manuka honey and bismuth both display adequate inhibitory effect with the films releasing Manuka honey having a marginally higher inhibitory effect as seen from slightly lower absorbances. The pectin films which combined both Manuka honey and bismuth (III) bromide however, showed the maximum inhibitory effect, almost comparable to the positive control of ampicillin. An interesting observation is that there is no significant decrease in growth rates of microbes after 24hrs with only a marginal decrease observed in most cases.

[0077] While no current theories are available for the synergistic effect of combining Manuka honey and bismuth salts, there have been a few studies looking into the synergistic effects of combining various bismuth salts with other common antimicrobials in order to retard the growth rate of standard pathogens. Furthermore, bismuth compounds and their corresponding salts have been reported to show synergistic antibiotic activity when administered in combination with many organic and inorganic antimicrobials. The exact mechanism which governs the synergy seen in the case of Manuka honey and bismuth (III) bromide still needs to be investigated. One possible explanation is that the bismuth ions are ‘hijack’ the sugar intake channels of the pathogens which is used by the microbes to bind to the sugar molecules present in the honey. The ions thus bypass the cell membrane of the microbes and lead to cell lysis. This method of sugar-uptake enhanced anti-microbial activity has been previously observed in case of other bacterial strains such as oral streptococci and maybe a possible mechanism of the observed synergistic effect.

[0078] Barrier properties and food preservation application of the plant-based biopolymeric coating composition:

[0079] The barrier properties and food preservation applications of the plant-based biopolymeric coating composition is evaluated by coating the freshly cut fruits and whole fruits with the plant-based biopolymeric coating composition and is analysed for their shelf life during storage.

[0080] Fresh red plum (prunus domestica) is cleaned thoroughly and weighed using a method adapted from Marquez et al. The pieces of the cleaned red plum is then initially dipped in 2% Calcium Chloride solution for 10 minutes followed by drying for an additional 10 minutes. The fruit pieces are then dipped in plant-based biopolymeric coating composition (cross-linked polymer solution comprising plurality of hydrogels of pectin incorporated with manuka honey and bismuth (III) bromide for 5 minutes before being allowed to drain and dry for 10 minutes. The coated fruit samples are then stored under two separate conditions: room temperature ( ~80% humidity) and at 4°C storage in the refrigerator. The weight loses of the coated and uncoated fruit samples is calculated in triplicate for 0 to 6 days at an interval of 24 hrs.

[0081] Figure 16 (a) to 16 (b) illustrates the comparative graphical analysis of percentage weight loss in uncoated samples and samples coated with the coating in accordance with the present disclosure.

[0082] Oxygen permeability of the plant-based biopolymeric coating composition

[0083] The oxygen permeability of the plant-based biopolymeric coating composition is determined according to the ASTM D-3985 method using the MOCOM oxygen permeation testing analyzers. The oxygen permeability coefficient of the plant-based biopolymeric coating composition is in the range of 0.5 to 3 g/day/m2.

[0084] Technical Advantages and Economical Significance

[0085] In an embodiment of the present invention, the physiochemical properties of the hydrogels of pectin (pectin films) in the plant-based biopolymeric coating composition can be altered depending upon the relative concentration of pectin and its complementary biopolymer to generate polymer composites with varied potential applications.

[0086] The reduced solubility, increased stretchability and higher water vapour permeability of the hydrogels of pectin (pectin films) in the plant-based biopolymeric coating composition of the present invention facilitates the application of these pectin films in food packaging applications and innovative packaging applications such as incorporation of the active compounds such as Manuka honey and anthocyanins giving rise to “active packaging” and “intelligent packaging systems” with application in food preservation. The successful incorporation of manuka honey into the pectin films coupled with ability to specifically tune the water vapor permeability of the pectin films allow for possible future application in would healing. While the application of pectin films incorporated with manuka honey in would healing has previously been explored, the addition of robust and tuneable polymer blend could further enhance its usefulness in such applications.

[0087] Bismuth ions incorporated with pectin films forms stable aggregates with the individual pectin chains via coordination bonds that leads to the formation of stable colloidal gel. While both honey and bismuth ions are able to exert an appreciable antibiotic effect on their own, the combination of manuka honey and bismuth have significantly enhanced inhibitory effect when incorporated into the pectin-CMC-PEGDE matrix, as seen above in the zone of inhibition and optical density experiments. While there is no consensus as to why this synergy is observed between manuka honey and bismuth ions, a few hypotheses on metal ions being able to disrupt the cell membranes of pathogens allowing for the easier entry of other actives, have been suggested. The plant based biopolymeric coating retard the rate of ripening and microbial degradation when applied to the surface of the fruit.

[0088] While the present invention has been described above in terms of specific embodiments, it is to be understood that the invention is not intended to be confined or limited to the embodiment disclosed herein.

,CLAIMS:We claim,

1. A plant-based biopolymeric coating composition for enhancing the shelf life of a perishable item, the biopolymeric coating composition comprising:
a polymer solution comprising a plurality of hydrogels of pectins;
a pre-defined amount of manuka honey; and
a pre-defined amount of bismuth (III) bromide,
wherein the plurality of hydrogels of pectins are fabricated by crosslinking a pre-defined ratio of pectin with at least one bio-polymer in presence of a cross-linking agent;
wherein the pre-defined amount of manuka honey is in the range of 10% to 20% w/v of the polymer solution; and
wherein the pre-defined amount of bismuth (III) bromide is in the range of 0 to 2.5% (w/v).

2. The coating composition as claimed in claim 1, wherein the predefined ratio of pectin with atleast one bio-polymer is in the range of 1:1 to 1:4.

3. The coating composition as claimed in claim 1, wherein the atleast one bio-polymer is selected from a group comprising of methyl cellulose, alginate and carboxy methyl cellulose.

4. The coating composition as claimed in claim 1, wherein the cross-linking agent is selected from group comprising of calcium chloride, citric acid, glutaraldehyde, ethyl di-glycidyl ether and Polyethylene glycol diglycidyl ether (PEGDE).

5. The coating composition as claimed in claim 1, wherein the biopolymeric coating composition is edible.

6. The coating composition as claimed in claim 1, wherein the biopolymeric coating composition is anti-microbial in nature due to the presence of pre-defined amount of manuka honey and pre-defined amount of bismuth (III) bromide.

7. A method of synthesizing a plant-based biopolymeric coating composition for enhancing the shelf life of a perishable item, the method comprising the steps of:
fabricating a polymer solution comprising a plurality of hydrogels of pectin by crosslinking a pre-defined ratio of pectin with at least one bio-polymer in presence of a cross-linking agent; and
adding a pre-defined amount of manuka honey and a pre-defined amount of bismuth into the polymer solution comprising the plurality of hydrogels of pectin,
wherein the predefined amount of manuka honey is in the range of 10% to 20% w/v of the polymer solution; and
wherein the predefined amount of bismuth (III) bromide is in the range of 0 to 2.5% (w/v).

8. A product comprising a perishable item and a plant-based biopolymeric coating formed on the perishable item based on the plant-based biopolymeric coating composition as claimed in claim 1,
wherein the coating is formed on the perishable item by applying a layer of the plant-based biopolymeric coating composition by using at least one of a coating application process.

9. The product as claimed in claim 8, wherein the coating application process is selected from dip-coating, spray-coating, spin coating, powder-coating, wrapping sealing, covering, layering or any combination thereof.

10. The product as claimed in claim 8, wherein the layer of the plant-based biopolymeric coating composition has a thickness in the range of 0.1 to 0.2 mm.

11. The product as claimed in claim 8, wherein the plant-based biopolymeric coating provides an oxygen permeability coefficient in the range of 25 to 100 cc m-2 day-1.

12. The product as claimed in claim 8, wherein the plant-based biopolymeric coating has a water diffusivity in the range of 0.5 to 3 g/day/m2.

13. The product as claimed in claim 8, wherein the plant-based biopolymeric coating exhibit less water- solubility in the range of 0.5 to 8%.

14. The product as claimed in claim 8, wherein the perishable item is selected from a group comprising of fruits, vegetables, flowers, plants, meat, poultry, sea foods.