Fresh Produce Quality, All Wrapped Up

18 Jul 2016

Nine out of 10 British consumers buy fresh produce every week and both fruit and vegetables sectors recorded double-digit growth in value terms between September 2014 and September 2015 – 14.2% and 10.1% respectively . The Netherlands, as Europe’s number one exporter of fresh vegetables , produced fruit and vegetables worth €2.9billion in 2014 . Drivers behind this expansion include the continuing trend for healthy eating, the growing diversity of produce now available, and increasing shopping frequency. In addition, on-the-go lifestyles call for convenient eating solutions. The combination of these factors places the fresh produce category – prepared fruits and vegetables, in particular – in a strong position for growth.

As consumer expectations remain high and sales soar, packaging is becoming an increasingly important aspect of the fresh produce market, particularly in Western Europe, which spends €470 million on packaging. Food waste also plays a pertinent role: Europe’s annual food and drink waste amounts to approximately 100 million tonnes, with households the largest contributors due to food not being consumed in time. Effective and innovative packaging options are therefore required to ensure high quality, profitable produce from farm to fork.

Defining quality
Consumers seek specific characteristics from their fresh produce purchases, all of which influence their perception of quality. With more and more people willing to pay a premium for quality, delivering a superior product is more a requisite than a luxury for growers, packers and retailers.

The critical influencers of quality for a consumer include food safety – at the most fundamental level, produce must be fit for consumption, even if supply chains are long; appearance; appropriate and effective packaging; shelf life – the later the “best before date”, the fresher (and therefore more desirable) the produce is perceived to be; nutritional value; and flavour – perhaps the most important factor in acceptability, but not even experienced if the other four criteria have not met consumer expectations.

The abundance of produce outlets and intense competition mean consumers don’t have to settle for second best. They demand products that deliver on all these criteria. Packaging, once ancillary and scarcely considered, is today integral to maintaining quality in all six areas.

From farm to fork: the role of respiration
Following harvest, ready-to-eat and fresh-cut fruit and vegetables are continuously ripening and ageing, which ultimately results in degeneration. They ‘breathe’ through the process of respiration, during which products consume oxygen (O2) and produce carbon dioxide (CO2). Items with higher respiration rates, such as strawberries, avocados and asparagus, tend to be more perishable and decompose at a faster rate. Fresh-cut fruit and vegetables respire more quickly due to the self-healing that occurs as cells repair surface damage.

Numerous factors affect respiration rates, including produce type and variety; growing conditions, handling and seasonality; conditions during harvesting and post-harvest handling; microbiology; maturity and ripeness level; levels of O2, CO2 and ethylene (the natural plant hormone that triggers ripening); and temperature. These can influence how products age and their freshness, which have a direct impact on the shelf life.

Naturally, air contains about 21% O2 and 0.04% CO2. Respiration can be decelerated with the combined reduction of O2 and increase in CO2, which can positively affect cell metabolism in various ways. These include a reduction in respiration, ethylene production and sensitivity. Modified atmosphere packaging (MAP) has been designed to adjust gas concentrations around a food to reach the required equilibrium ratio of O2 and CO2. Slowing down deterioration helps to avoid health hazards, maintains nutritional value, visual appeal, texture, aroma and flavour and, above all, extends shelf life.

The importance of shelf life
Successful management of the above factors is key to ensuring fresh produce quality. Once achieved, the time and quality benefits are plentiful:

Extending shelf life helps to reduce food waste throughout the supply chain and at home, significantly impacting the environment and people’s pockets;
Out-of-season pur chases due to greater opportunity for crop availability and season longevity;
Cost savings through waste reduction and the higher value that longer-lasting produce retains;
Maintained quality thanks to delayed degradation;
Market expansion – shelf life extension permits activity in more remote regions.

To extend shelf life, respiration can be controlled in a two-pronged approach. The first method is lowering temperature – an integral component of cool chain management. Temperature breaks and ‘periods of abuse’ are inevitable, certainly as products travel between the temperature-controlled shelf and home, but also commonly further upstream. By maintaining cool chain integrity, respiration is controlled and deterioration is minimised.

Packaging material also plays an important role. Simple hole-punched film is a cost-effective, easy-to-use option that enables reasonable control of moisture in a variety of low respiring applications such as tomatoes, grapes and potatoes, though offers no control of O2 and CO2 levels within the pack or entry of contaminants. With hot needle perforation, holes of 200-1000 micron are punched into (normally pre-printed) film. These holes, however, have been found to show very large variation due to lack of consistency and do not modify gas levels.

Controlling atmosphere
MAP is an alternative, highly effective option that can be introduced at the packing stage to control gas levels, reducing respiration and preserving product quality. Since fruit and vegetables continue to respire after harvest, passive (rather than active) MAP is necessary to allow unforced, gradual changes in O2 and CO2 levels. This requires microperforated film which, as well as allowing the produce to modify its own atmosphere naturally, also allows the equilibrium to recover after periods of temperature abuse. Studies have shown a significant extension in fresh produce shelf life when passive MAP is combined with accurate temperature control.

The most recent and effective microperforation process for flexible packaging films is using lasers. As the laser pulses, its intense light is readily absorbed by the film, which heats, melts and vaporises, leaving a small, distinct hole. Deemed the most efficient and practical option thanks to its flexibility, consistency and productivity, laser-based perforation is particularly credited for its accuracy. It does not, however, overcome the issue of different permeation profiles being needed not only for different species and storage conditions, but also occasionally for different varieties, batches and origins.

Tailored choice
Not a new MAP method, but one which is time-honoured and continues to prosper, tailored permeability perforation of carefully-selected flexible packaging films (TPF) is designed to match precisely the unique respiration rate of the product inside the pack. Based on a combination of horticultural science and advanced packaging technology, TPF uses advanced laser-controlled micro-perforation technology to specify the size and density of the minute holes.

Tailoring the extra mile
Some MAP technologies go a step further. P-Plus® from Amcor, for example, is a laser-controlled TPF technology whose advanced technical features guarantee a substantial increase in shelf life and maintain product quality for a myriad of fresh produce applications. It comprises an extensive range of tailored permeability films, from mono films such as oriented polypropylene, polyester and polyethylene to sophisticated laminates and coextrusions. P-Plus® can also offer continuous perforation or perforation to register – particularly suitable as no perforations are lost in the seal area – according to the specific profile of the packed produce.

Further critical considerations are also taken into account. The required gas modification is initially calculated by using experience of similar produce and predictive modelling. This is then tailored following comprehensive testing, which enables the determination of an optimum specification. Food technology, packaging design and production teams provide end-to-end support throughout development and implementation, which is supplemented by field technical service (FTS), where an expert team of engineers is available to customers to ensure that films run perfectly on their lines. This close collaboration is invaluable in defining the P-Plus® tailored permeability solution.

Conclusion
The financial and environmental impact of food waste is a fundamental driver behind the effort to prolong fresh produce quality. Growers’, packers’, processors’ and retailers’ bottom lines are all affected, while unacceptable volumes of imperfect, overripe and rotten fruit and vegetables are sent to landfill. These social and economic factors, coupled with expanding global supply networks, mean maintaining the integrity and quality of fresh food is a difficult yet essential priority.

Tailored permeability constitutes a real solution to overcome the challenges associated with fresh produce respiration, safety, waste and quality. Furthermore, it is proven in many applications, to have clear and significant commercial benefits for growers, packers and retailers. With leading packaging suppliers like Amcor developing further solutions for new applications to preserve food for even longer, while offering invaluable partnership and support, switching to tailored permeability film will continue to provide unrivalled qualitative and cost benefits throughout the fresh produce supply chain.

Source: Amcor Flexibles