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Current innovations in food packaging
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Wednesday, 15 December, 2021, 14 : 00 PM [IST]
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Katke S.D & Deshpande H.W
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Packaging is one of the most important processes to maintain the quality of food products for storage, transportation and end-use. The basic functions of packaging are considered as protection, containment, information and convenience. Food packaging was initially considered to increase the marketable life of the food in a container by protecting it from the influence of the environmental factors.
Then it was expected to be informative, easy-to-handle and disposal- friendly with increased functionality. Current innovations of food packaging technology are geared to ensure one or all of these properties along with better protection, more efficient quality preservation and enhanced safety of the packaged food. Innovative packaging technologies also prevent the rate of quality deterioration and facilitate easy handling of the produce during distribution and marketing. During distribution, the quality of the food product can deteriorate biologically and chemically as well as physically. Innovative packaging technologies are the most important and challenging technologies to overcome these limitations. These technologies require specific knowledge and appropriate training and understanding for rationally selecting the most suitable packaging for each product and intended use.
Bio-Based Packaging
The worldwide interest in bio-based polymers has accelerated in recent years in order to find non-fossil fuel based polymers which are biodegradable and does not cause pollution. The term ‘biodegradable' is used to describe those materials which can be degraded by the enzymatic action of living organisms such as bacteria, yeasts and fungi. The ultimate end products of degradation process are CO2, H2O and biomass under aerobic conditions while hydrocarbons, methane and biomass under anaerobic conditions.
Bio-based polymers are manufactured from polysaccharides (chitosan, carrageenan, starch, alginate), proteins (caseinates, whey protein isolates, soy protein, wheat gluten, corn zein) and lipids.
Nano based Packaging
Nanomaterials are increasingly being used in the food packaging industry due to the range of advanced functional properties they can bring to packaging materials.
Nanotechnology enabled food packaging can generally be divided into three main categories.
1)Improved packaging (whereby nanomaterials are mixed into the polymer matrix to improve the gas barrier properties, as well as temperature and humidity resistance of the packaging).
2)Active packaging (illustrated by the use of nanomaterials to interact directly with the food or the environment to allow better protection of the product).
3)Intelligent or smart packaging (designed for sensing biochemical or microbial changes in the food).
Applications of Nano based Packaging
- Nano Encapsulation: Nano-encapsulation has been tested for the safe and controlled discharge of favorable live probiotic cells to boost healthy gut function. The sustainability of probiotic organism such as Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus, and Bifidobacterium spp. which are present in the freeze-dried yogurt can be amended through nano-encapsulation with the help of calcium alginate.
- Nano Composite: Nanocomposites are polymer matrices reinforced with nanomaterials such as nanoparticles. These materials have at least one dimension on the nanometer scale (10-9m) and are composed of a variety of materials including metal ions (such as silver, copper, and gold) and metal oxides (TiO2, MgO). The assimilation of different nanoparticles such as SiO2, clay, TiO2, KMnO4, nano cellulose, nano fibrillated cellulose and carbon nanotubes are capable of amending the packaging material in terms of mechanical and barrier properties.
- Nano Emulsions: The operations such as the targeted delivery of lipophilic products for example nutraceuticals, medicines, flavour, antioxidants and antimicrobial agents are accomplished by these carriers named nano-emulsions.
- Edible Nano Coatings and Nano Coating Materials: Films made from edible comprises of water-soluble polysaccharides (hydrocolloids) and lipids. The most commonly used polysaccharides are cellulose derived such as alginates, pectins, starches, chitosan and other polysaccharides. Polysaccharide gives variety of properties like rigidity, firmness, thickening quality, viscosity, adhesive and gel-forming capability. Different types of lipid complexes like animal and vegetable fats have been employed for synthesising the edible films and coatings.
- Nano-sensors: Packaging equipped with nano-sensors is also designed to track either the internal or external conditions of food products, pellets and containers, throughout the supply chain. For example, Nano-sensors in plastic packaging can detect gases given off by food when it spoils and the packaging itself changes colour to alert the consumer. These films are packed with ‘silicate nanoparticles' to reduce the flow of oxygen into the package and the leaking of moisture out of the package to stay food fresh.
Shrink Packaging
Shrink Wrapping is a packaging technique which greatly reduces the moisture loss and maintains freshness of fresh produce for longer duration. Individual shrink packaging may be considered as modified atmosphere packaging (MAP), for individual fruit. It involves sealing of fruit in a flexible film followed by heat shrinking to confine the shape of fruit or container in which fruit is kept. Generally 10-20% reduction in transpiration rate is possible by shrink packaging even under ambient conditions.
Active Packaging
The term ‘active packaging' is defined as packaging which performs some desired function other than merely providing a barrier to the external environment. Active packaging is normally designed to address one property or requirement of the food or beverage. The property normally chosen is that most critical as the first limiting factor of quality or shelf life.
Many new ‘extra' functions have been introduced in active packaging technologies which include oxygen scavenging, carbon dioxide-absorbing, moisture-scavenging (desiccation), antimicrobial activity, atmosphere control, edibility, biodegradability etc. Active food packaging performs beyond its conventional protective barrier property. The new active packaging systems increase security, safety, protection, convenience, and information delivery. Active packaging systems extend the shelf life of food products by maintaining their quality longer, increase their safety by securing foods from pathogens and bio terrorism and enhance the convenience of food processing, distribution, retailing and consumption.
Active packaging systems for processed foods and beverages:
- Oxygen-scavenging systems: It has been commercialized in the form of a sachet that removes oxygen. An oxygen-free environment can prevent food oxidation and rancidity and the growth of aerobic microbes.
- Carbon dioxide scavenging systems: It can prevent packages from inflating due to the carbon dioxide formed after the packaging process e.g. packaged coffee beans may produce carbon dioxide during storage as a result of non-enzymatic browning reactions. Similarly fermented products such as kimchi (lactic acid fermented vegetables), pickles, sauces, and some dairy products can produce carbon dioxide after the packaging process. Carbon dioxide-scavenging systems are also quite useful for the products that require fermentation and aging processes after they have been packed.
- Moisture scavenging systems: Recently, the sachets have contained humectants as well as desiccants to control the humidity inside the package more specifically. Moisture-scavenging systems that are based on desiccation are evolving to control the moisture by maintaining a specific relative humidity inside the package by absorbing or releasing the moisture.
- Antimicrobial packaging systems: Antimicrobial packaging is a system that can kill or inhibit the growth of micro-organisms and thus extend the shelf life of perishable products and enhance the safety of packaged products. Edible antimicrobial agents can be incorporated into food ingredients, while antimicrobial resources can be interleaved in the in-package headspace in the form of sachets, films, sheets or any in-package supplements, to generate antimicrobial atmospheres. Organic acids, bacteriocins, enzymes, bacteriophages, essential oils etc. are used as antimicrobial agents in the packages. Besides, gaseous agents like carbon dioxide for modified atmosphere packaging, sulfur dioxide for berries and ethanol vapor for confections to inhibit the growth of microorganisms.
Intelligent Packaging:
Intelligent packaging has been categorized both as a part of active packaging and as a separate entity, depending on different viewpoints. The term is used to represent class of packaging materials that can monitor the condition of either the packaged food or the food environment inside the package which includes temperature, pH, and provides this information to the user. It can be interpreted as an extended function of traditional packaging which is responsible for communication with the consumer depending on its ability to sense and record the changes taking place in the food or its environment.
An added advantage of intelligent packaging is its contribution to the improvement of Hazard Analysis and Critical Control Points (HACCP) and Quality Analysis and Critical Control Points (QACCP) systems and hence onsite detection of unsafe food products, identification of potential health hazards and establishing strategies to abate their occurrence, ultimately leading to improved food quality. The intelligent systems can be classified into three categories; i) sensors, ii) indicators and iii) radiofrequency identification (RFID) systems.
Table 1. Innovations in intelligent packaging for foods
| | | | | | Various commercial biosensor based packaging materials available in the market | | Gas sensors are employed for the detection of gaseous analytes like oxygen, water vapor, carbon dioxide, ethylene, etc. inside the package. The use of pH sensitive dyes like methyl red and curcumin for the detection of basic volatile amine released from rotten meat and fish have been reported. | | These can adsorb a particular chemical on the surface and detect its presence, composition, activity or concentration have been employed as chemical sensors. Carbon based nanomaterials like graphene, carbon nanotubes and carbon nanofibers are used as chemical sensors. | | Instruments have been designed to identify and classify the mixture of aromas in an odor on a repeatable basis – a function similar to that of the mammalian olfactory system. The instrument is composed of an array of sensors, either chemical sensors or biosensors, which show partial specificity to each kind of odor. The statistical methods are used to recognize simple and complex odor and produce a unique response towards each one. Successful testing of electronic nose system has been carried out in response to the odor released by fresh yellow fin tuna, vacuum packed beef, fruits and vegetables, and broiler chicken. | | | | These indicators provide information about the product quality by determining the chemical changes resulting from the microbial growth within the product. The microbial growth metabolites react with the indicators integrated inside the food package to give visual information regarding the product quality. | | | Time temperature indicators (TTIs) | TTIs are labels that provide visual indication of the temperature abuse of temperature dependent perishable products, like frozen foods, during distribution and storage from the point of production to the point of consumption. There are three basic types of TTI available in market: critical temperature indicators, partial history indicators and full history indicators. | | | | Integrity indicators function to ensure their integrity. Visual oxygen indicators are composed of redox sensitive dyes which change colour with change in oxygen concentration in MAP foods. | | | Radiofrequency identification (RFID) systems | RFID is a tag or reader based automatic identifications system used for item identification and data accumulation without human intervention. RFID tags have some identification number stored in their databases and are able to accordingly act upon it by retrieving the information about that number from the database. RFID tags for monitoring temperature, relative humidity, pressure, pH, and light exposure of the products are already available in the market which aid in enhancing food quality and safety. These are more advanced, reliable and efficient than the conventional barcode tags for food traceability. |
Edible films and coatings
The use of edible films and coatings is an application of active food packaging, since the edibility and biodegradability of the films are extra functions that are not present in conventional packaging systems. Edible films and coatings are useful materials produced mainly from edible biopolymers and food-grade additives. Most biopolymers are naturally existing polymers, including proteins, polysaccharides (carbohydrates and gums), and lipids. Plasticizers and other additives are included with the film-forming biopolymers in order to modify film physical properties or to create extra functionalities.
The application of edible films and coatings is an easy way to improve the physical strength of the food products, reduce particle clustering, and enhance the visual and tactile features of food product surfaces. The most common functions of edible films and coatings are that they are barriers against oils, gas or vapors, and that they are carriers of active substances such as antioxidants, antimicrobials, colours and flavours.
Aseptic packaging
Aseptic packaging is an alternative to conventional canning in the production of shelf stable packaged food products. Aseptic packaging technology is fundamentally different from that of traditional food-processing systems. Canning processes commercially sterilise filled and sealed containers, while in aseptic packaging the presterilised product is filled into sterilised containers that are hermetically sealed in a commercially sterile environment. This form of heat treatment enables the commercial sterilization of the product, and results in minimal loss of product quality and nutrition. Various methods for the sterilisation of packaging materials are currently used in aseptic packaging systems. Hydrogen peroxide sterilisation followed by hot air appears to have the most potential for use as in-line sterilisation of packaging materials. Sterilisation of packaging materials followed by ultraviolet irradiation has also been accepted for industrial application. Ultraviolet irradiation promotes the breakdown of peroxides into hydroxyl radicals, and the overall lethal effect is greater than the sum of the effects of peroxide and irradiation alone.
On-the-go packaging
Owing to consumer’s preference for easy and quick consumption of food while they are on the move, the packaging industry is focusing on the go packaging solution to meet the augmented demand for packaged and processed foods. The global on the go packaging market is expected to have a steady growth over the forecast period attributed to the increasing demand for easy usage and consumption of products. Growing affinity of the consumers for portability, easy usage, re- usability, and re-closable characteristics is expected to boost the global on the go packaging market.
(The authors belong to College of Food Technology, VNMKV, Parbhani, Maharashtra)
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