Characterization and antimicrobial effect of starch-based edible coating suspensions

Nanotechnology in food packaging materials: role and application of nanoparticles

Global concerns about food security, driven by rising demand, have prompted the exploration of nanotechnology as a solution to enhance food supply. This shift comes in response to the limitations of conventional technologies in meeting the ever-increasing demand for food products. Consequently, nanoparticles play a crucial role in enhancing food production, preservation, and extending shelf life by imparting exceptional properties to materials. Nanoparticles and nanostructures with attributes like expansive surface area and antimicrobial efficacy, are versatile in both traditional packaging and integration into biopolymer matrices. These distinctive qualities contribute to their extensive use in various food sector applications. Hence, this review explores the physicochemical properties, functions, and biological aspects of nanoparticles in the context of food packaging. Furthermore, the synergistic effect of nanoparticles with different biopolymers, alongside its different potential applications such as food shelf-life extenders, antimicrobial agents and as nanomaterials for developing smart packaging systems were summarily explored. While the ongoing exploration of this research area is evident, our review highlights the substantial potential of nanomaterials to emerge as a viable choice for food packaging if the challenges regarding toxicity are carefully and effectively modulated.

From trash to treasure: review on upcycling of fruit and vegetable wastes into starch based bioplastics

Growing public concern toward environmental sustainability is currently motivating a paradigm shift toward designing easily degradable plastics that can replace conventional synthetic plastics. The massive rise in food waste generation has led to an increased burden on landfills, thereby resulting in the higher emission of greenhouse gases. Using this food waste to produce bioplastics will benefit not only the environment but also develop a systematic food waste management system. Moreover, bioplastics are preferred due to the use of biomaterials derived from renewable resources. Furthermore, bioplastics degrade faster than conventional synthetic plastics, which take years to degrade. The biodegradation of bioplastics occurs under normal environmental conditions and disintegrates into carbon dioxide, water, biomass, and inorganic compounds without producing hazardous residues. In this review, we will discuss the synthesis of starch based bioplastics using discarded parts of various fruits and vegetables. Furthermore, we will address the importance of various components in the development of starch based bioplastics, such as fillers, plasticizers, and other additives that are essential in providing the bioplastic with different physio-mechanical properties. Therefore, bioplastic production using food waste will pave the way to achieve systematic waste management and environmental sustainability in the near future.

Investigation of the effect of the amount of film-forming coatings based on natural biopolymers on the quality characteristics of grape berries

Post-harvest losses of grapes during prolonged storage in refrigerated chambers are mainly associated with dehydration and darkening of stems, wilting of berries and the development of mold. As a result of the physiological processes in the berries, a sufficiently humid environment is created, which contributes to the development of microbiological spoilage. To combat this phenomenon, it is recommended to use natural biodegradable polymers, which prevent the deterioration of quality characteristics by creating a semi-permeable protective barrier. In this regard, the purpose of the study was to determine the optimal dosage of film-forming solutions for treatment of grapes. For this, samples of grapes of the Kishmish Luchistyi variety were prepared with an applied to the surface coating layer of two types: potato starch/gelatin/glycerin/ natamycin and chitosan/sodium alginate/glycerin/natamycin at a biopolymer ratio of 50/50%, with the addition of 1.3% glycerin and 0.3% natamycin. Based on the identified dependence of the weight loss and the value of the resistance of berries to the pressure force on the storage time and the amount of film-forming coating, the optimal amount of film-forming coating required to treat 1000 grams of berries is substantiated – 50 ml.

Film formation and deposition methods of edible coating on food products: A review

The greatest challenge encountered by the food manufacturer is the loss of quality of food products during storage, which eventually adds to the waste. Edible packaging is known as a potential alternative to protecting food quality and improving shelf life by delaying microbial spoilage and providing moisture and gas barrier properties. Developments in edible packaging and technology have shown promising results in enhancing the shelf life of food products. In 2016, the edible packaging market was valued at $697 million and by 2023 is expected to hit $1097 million growing at a compound annual growth rate (CGAR) of 6.81% from 2017 to 2023 at global level. In global edible packaging markets specific industries including MonoSol LLC, Tate & Lyle Plc, WikiCell Designs Inc., JRF Technology LLC, Safetraces, Inc., BluWrap, Skipping Rocks Lab, Tipa Corp., Watson Inc., and Devro plc have played a key role. Edible packaging can be applied in two forms: (i) edible coating applied directly on the food product or (ii) preformed film wrapped around the food product. The aim of this study is to review different methods of film formation and edible coating depositions. Edible films can be produced using two methods, wet (casting) and dry (extrusion) processes; and methods such as dipping, spraying, fluidized-bed, and panning are used for deposition of edible coatings on the surface of food product. Casting and dipping methods for film formation and coating deposition, respectively, are easy to use and are preferred methods on a lab scale; whereas extrusion and spraying are preferred methods for film formation and coating deposition, respectively, on a commercial scale. This work can help researchers and industries to select an efficient and cost-effective method for the development of edible film/coating for specific application. Further study and evaluation of practical applications of methods of edible packaging should be carried out within the main purpose of keeping food safe with acceptable quality for extended period of time.

Novel Edible Coating of Starch-Based Stenospermocarpic Mango Prolongs the Shelf Life of Mango “Ataulfo” Fruit

Edible coatings based on 2% starch (w/v) extracted from tropical fruits were applied on stenospermocarpic mango fruits with the objective to prolong its shelf life during storage and give them an added value since they have no commercial value. In this regard, stenospermocarpic mangoes were coated with starch from banana “Pear” (T1 and T2), starch from soursop (T3 and T4), and starch from stenospermocarpic mango (T5 and T6), and two uncoated control treatments (T7 and T8). The fruit of T1, T3, T5, and T7 treatments were stored for 15 days (10 days at 10 ± 2°C and then at 22 ± 2°C for 5 days). The fruit of T2, T4, T6, and T8 treatments were stored for 10 days at 22 ± 2°C. Data were analyzed with a 4×2 factorial experimental design. Weight loss (g), firmness (N), total soluble solids content (%), titratable acidity (%), and color (L∗h∗C∗) were evaluated. The fruit coated with mango starch (T5) showed less weight loss (2.57%), greater firmness (18.6 N), as well as a high content of TSS (28.76%) compared with the control. The T5 extended the shelf life of the fruit up to 15 days (10 days at 10 ± 2°C and 5 days at 22 ± 2°C).

Synthesis, characterization, and antimicrobial efficacy of composite films from guar gum/sago starch/whey protein isolate loaded with carvacrol, citral and carvacrol-citral mixture

The aim of this research was to formulate antimicrobial, composite films of guar gum, sago starch, and whey protein isolate for the prophylaxis of the bacterial gastroenteritis. The model antibacterial agents incorporated were essential oils, namely, carvacrol, citral and their combination. The films became darker and brownish in color due to the entrapment of the oils. The surface of the oil-entrapped films was more rough and coarse compared to the control film. Confocal micrographs affirmed the uniform distribution of the oil droplets within the biopolymeric network. The highest crystallite size and lowest lattice strain were estimated in the citral-containing film. FTIR analysis demonstrated that the incorporation of citral increased the proportion of the β-sheet structures of the whey protein isolate within the film matrix. However, the film formulation containing combination of carvacrol and citral demonstrated the lowest water vapor transmission rate (WVTR), highest tensile strength, Young's modulus and work to failure. All the oil-containing films demonstrated good antibacterial potency against the model bacterial gastroenteritis causing bacteria, namely, Bacillus cereus and Escherichia coli. In gist, it can be concluded that the prepared antimicrobial films could be used for the prophylaxis of the bacterial gastroenteritis.

Polysaccharide-based component and their relevance in edible film/coating: a review

Purpose

The purpose of this paper is to present an overview of functional properties of the polysaccharide-based component and their application in developing edible film and coating for the food processing sector.

Design/methodology/approach

In this review study, approximately 271 research and review articles focusing on studies related to polysaccharide-based components and their film-forming properties. This article also focused on the application of polysaccharide-based edible film in the food sector.

Findings

From the literature reviewed, polysaccharide components and components-based edible film/coating is the biodegradable and eco-friendly packaging of the materials and directly consumed by the consumer with food. It has been reported that the polysaccharide components have excellent properties such as being nontoxic, antioxidant, antimicrobial, antifungal and with good nutrients. The polysaccharide-based edible film has lipid and gas barrier properties with excellent transparency and mechanical strength. In various studies, researchers worked on the development of polysaccharide-based edible film and coating by incorporating plant based natural antioxidants. This was primarily done for obtaining improved physical and chemical properties of the edible film and coating. In future, the technology of developing polysaccharide-based edible film and coating could be used for extending the shelf life and preserving the quality of fruits and vegetables at a commercial level. There is more need to understand the role of edible packaging and sustainability in the food and environment sector.

Originality/value

Through this review paper, possible applications of polysaccharide-based components and their function property in the formation of the edible film and their effect on fruits, vegetables and other food products are discussed after detailed studies of literature from thesis and journal article.

Morphology and Surface Properties of Roach Water Transport Arrays

We report on morphological studies of wharf roaches, Ligia exotica, which can passively absorb and transport water through the microscopic protrusions on their legs. We systematically investigated the geometrical variables of the protrusions on each podite of legs to reveal a particularized structural complexity. For the morphological analysis, each podite was split into nine different zones by grouping the protrusions with similar shapes and organization. The protrusions are shown to possess three different types of shapes located on each specific zone of the podite. In addition, the nanoscale surface morphologies of the protrusions on the wharf roach legs were probed by using atomic force microscopy, and the surface properties of the hairy arrays were determined for identifying the localized hydrophobicity distribution. The protrusion surface possessed a nanoscale periodic patterned texture, and both the valley and ridges of a periodic pattern on the protrusion surface exhibited an identical low surface energy. We suggest that the structural morphologies and distinct hydrophobicity of the protrusions can be critical in determining the directional wettability of an entire leg and important for designing a sturdy water transport and passive water-absorbing system without external energy consumption.

Quality Control of Fresh-Cut Apples after Coating Application

The growing demand for ready-to-eat fresh fruits has led to set-up appropriate strategies for preserving fruit quality and freshness of such commodities. To slow down the deterioration events such as respiration, moisture loss and enzymatic activity, ready-to-eat products should be protected with an edible film. A suitable coating should combine hydrophilic and hydrophobic features to ensure good mechanical and gas barrier properties. Alginate/essential oil nanoformulations, one with low and the other with high oil content, here proposed to protect apple pieces during storage, were first characterized through dynamic light scattering and rheology. The effect of the application of the nanoformulations on the quality parameters of apples stored at 4 °C was considered by evaluating weight loss, pH and titratable acidity, total phenols content and the fruit appearance during storage. Mainly on the basis of pH and titratable acididty variation, the nanoformulation with low oil content resulted eligible for preserving the quality of fresh-cut apple pieces during storage.

Spectroscopic and Structural Analyses of Opuntia Robusta Mucilage and Its Potential as an Edible Coating

Mucilage extracted from the parenchymatous and chlorenchymatous tissues of Opuntia robusta were obtained using water or ethanol as the extraction solvent. The changes in the different tissues by using different extraction solvents were evaluated via scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) and Raman spectroscopy; in addition, the effect of mucilage coating on the various quality characteristics of tomato (Lycopersicum sculentum) was evaluated. The SEM results showed that the mucilage extracted from the parenchyma had a higher aggregation level that the mucilage extracted from the chlorenchyma. The presence of three characteristic bands of pectic substances in the FT-IR spectra between 1050 and 1120 cm−1 indicated that the mucilage extracted from the parenchymatous tissue had a higher content of pectic compounds than the mucilage extracted from the chlorenchymatous tissue. It was also observed in the Raman spectra that the level of pectic substances in the mucilage extracted from the parenchymatous was higher than that in the mucilage extracted from the chlorenchymatous tissue. The mucilage extracted from the parenchymatous tissue was more effective as an edible coating than the mucilage extracted from the chlorenchymatous tissue. Tomatoes covered with mucilage showed significantly enhanced firmness and reduced weight loss. The uncoated tomatoes showed higher lycopene content than the coated tomatoes on the 21st day. This study showed that the Opuntia robusta tissue and extraction solvent influence mucilage characteristics and that Opuntia robusta mucilage is a promising edible coating.

Effect of an Edible Coating Based on Chitosan and Oxidized Starch on Shelf Life of Carica papaya L., and Its Physicochemical and Antimicrobial Properties

Papaya production plays an important economic role in Mexico’s economy. After harvest, it continues to ripen, leading to softening, skin color changes, development of strong aroma, and microbial spoilage. The objective of this work was to apply an active coating of chitosan–starch to increase papaya shelf life and to evaluate physicochemical and antimicrobial properties of the coating. Papaya surfaces were coated with a chitosan-oxidized starch (1:3 w/w) solution and stored at room temperature (25 ± 1 °C) for 15 days. Variables measured were color, titratable acidity, vitamin C, pH, soluble solids, volatile compounds by gas chromatography, texture, homogeneity by image analysis, and coating antimicrobial activity. At the end of the storage time, there were no significant differences (p > 0.05) between coated and uncoated papayas for pH (4.3 ± 0.2), titratable acidity (0.12% ± 0.01% citric acid), and soluble solids (12 ± 0.2 °Bx). Papaya firmness decreased to 10 N for coated and 0.5 N for uncoated papayas. Volatile compounds identified in uncoated papaya (acetic acid, butyric acid, ethyl acetate, ethyl butanoate) are related to fermentation. Total microbial population of coated papaya decreased after 15 days, whereas population of uncoated papaya increased. This active coating permitted longer shelf life of papaya than that of the uncoated fruit.

The influence of Aloe vera gel incorporation on the physicochemical and mechanical properties of banana starch-chitosan edible films

BACKGROUND

Aloe vera (AV) gel is a promising material in food conservation, given its widely reported antimicrobial and antioxidant activity; however, its application in the formation of edible films and coatings has been small owing its low film-forming capability. The aim of this study was to investigate the physicochemical properties of film-forming solutions and films prepared using unripe banana starch-chitosan and AV gel at different AV gel concentrations.

RESULTS

Our results showed that AV gel considerably affected the rheological and optical properties of the edible coatings, mainly due to increased amounts of solids brought by the AV gel. Film-forming capacity and physicochemical properties were also studied; most of the film properties were affected by the inclusion of AV gel, with decreased water vapor permeability, tensile strength and elongation at break. Fourier transform infrared studies showed that the inclusion of AV gel disrupts the interaction between starch and chitosan molecules; however, further studies are needed to fully understand the specific interactions between the components of AV gel and both starch and chitosan molecules.

CONCLUSION

Our results suggest that the addition of AV gel creates a crosslinking effect between the phenolic compounds in AV gel and starch molecules, which disrupts the starch-chitosan interaction and greatly affects the properties of both the film-forming solution and edible films. © 2018 Society of Chemical Industry.

Mechanical, barrier, and color properties of banana starch edible films incorporated with nanoemulsions of lemongrass ( Cymbopogon citratus) and rosemary ( Rosmarinus officinalis) essential oils

Edible films are among the most promising fields in food science over the last decade due to their versatility (they can be made from a wide array of materials) and because they can be used as carriers of different active substances, like antioxidants, antimicrobial agents, and essential oils from plants. In the case of the essential oils, their inclusion in edible films is limited by their low water solubility. Nanoemulsions are thermodynamically stable and transparent systems that can be used as a way of incorporating essential oils into edible film matrices. In this paper, we developed lemongrass and rosemary essential oil nanoemulsions by using a low-energy method, observing the effect of the surfactant/oil ratio in their physicochemical properties. Then we studied the effect of the nanoemulsions concentration incorporated into banana starch edible films. We observed that essential oils' nanoemulsions have a plasticizing effect increasing the film's water vapor permeability, transparency, and elongation at break, while the hydrophobic nature of the essential oils lead to a decrease in their water solubility.

Effects of carboxyl and aldehyde groups on the antibacterial activity of oxidized amylose

Dialdehyde-amyloses, dicarboxyl-amyloses and dialdehyde-carboxyl-amyloses with different oxidation levels were prepared and used to study the effects of aldehyde and carboxyl groups on the antibacterial activity of oxidized amyloses. The results showed that dicarboxyl-amyloses presented antibacterial activity through acidic pH effect produced by carboxyl groups, which was easily reduced or eliminated by adjusting pH. Dialdehyde-amyloses possessed a broad-spectrum antibacterial activity owing to the reactivity of aldehyde groups rather than acidic pH effect. Aldehyde would irreversibly damage bacterial cell wall and cytoplasmic membrane, resulting in decay and death of bacterial cells. It is interesting that the antibacterial properties of dialdehyde-carboxyl-amyloses were improved to some extent compared to dialdehyde-amyloses. The improvement of antibacterial effect of dialdehyde-carboxyl-amyloses may be due to the increasing dispersibility endowed by carboxyl groups, which could effectively enhance the interaction between dialdehyde-carboxyl-amyloses and bacteria. As a result, carboxyl group could act as a promising synergistic group against bacteria with aldehyde group.

Physicochemical and Antimicrobial Characterization of Beeswax-Starch Food-Grade Nanoemulsions Incorporating Natural Antimicrobials

Nanoemulsions are feasible delivery systems of lipophilic compounds, showing potential as edible coatings with enhanced functional properties. The aim of this work was to study the effect of emulsifier type (stearic acid (SA), Tween 80 (T80) or Tween 80/Span 60 (T80/S60)) and emulsification process (homogenization, ultrasound or microfluidization) on nanoemulsion formation based on oxidized corn starch, beeswax (BW) and natural antimicrobials (lauric arginate and natamycin). The response variables were physicochemical properties, rheological behavior, wettability and antimicrobial activity of BW-starch nanoemulsions (BW-SN). The BW-SN emulsified using T80 and microfluidized showed the lowest droplet size (77.6 ± 6.2 nm), a polydispersion index of 0.4 ± 0.0 and whiteness index (WI) of 31.8 ± 0.8. This BW-SN exhibited a more negative ζ-potential: -36 ± 4 mV, and Newtonian flow behavior, indicating great stability. BW-SN antimicrobial activity was not affected by microfluidization nor the presence of T80, showing inhibition of the deteriorative fungi R. stolonifer, C. gloeosporioides and B. cinerea, and the pathogenic bacterium S. Saintpaul. In addition, regardless of emulsifier type and emulsification process, BW-SN applied on the tomato surface exhibited low contact angles (38.5° to 48.6°), resulting in efficient wettability (-7.0 mN/m to -8.9 mN/m). These nanoemulsions may be useful to produce edible coatings to preserve fresh-produce quality and safety.