Cling film

Cling film is also known as plastic wrap, food wrap, or saran wrap, is a thin plastic film used for packaging food items in containers for keeping them fresh over a long period of time.

Cling film is a thin transparent plastic film adheres to surfaces and to itself, is used for sealing food items. Cling films are high-quality food wrap films, which prevent food from insects and microbial contamination, dust, keep it fresh, and also minimize the risk of wastage of food by increasing its shelf life.

Cling-wrap plastic films are usually made from polyethylene (PE) or plasticized polyvinyl chloride (PVC), whilst rigid containers are usually made from polystyrene, polyester, or polypropylene.

Polyvinyl chloride (PVC)- and polyethylene (PE)-based cling-films are widely used worldwide for wrapping cheeses. For this purpose, films used in retail possess suitable technical properties such as clinginess and unrolling capacity that are achieved by using specific plasticizers during their manufacturing process. Nowadays, food wrapping provides an attractive presentation and facilitates self-service shopping.

These materials have “stretch” properties and unique “cling,” and hence they are suitable for the hand-wrapping of fresh produce. Such films have high oxygen and water vapour transmission, keeping red meat “red” for longer periods on supermarket shelves. These materials can also be heat-sealed.
Cling film

Packaging for mangoes

Mangoes are traditionally known to have higher tolerance toward elevated CO2 concentrations. Mangoes can tolerate CO2 atmosphere of up to 25 kPa for 2 weeks at 12 °C. High (25kPa) CO2 inhibits ethylene production, but increase ethanol production.

For the domestic market, fruits may be packed in ventilated wooden boxes or corrugated cardboard boxes with a net capacity of 18-20 kg. Fruits should not be packed more than two layers deep.

Mangoes destined for the export market should be packed in ventilated cardboard cartons. One-layer flats with dividers with a maximum capacity of 8 kg may be used. If it is necessary to have more than one layer of mangoes in the package unit, then liners should be used to protect fruits from compression damage.

Packaging of mangoes is crucial in obtaining optimal; flavor. The fruits need to be ventilated well within the packages and packing of the fruit in polyethylene-lined cardboard boxes often results in off-flavor development due to accumulation of CO2 and suboptimal decrease in the oxygen concentration leading toward anerobiosis.

Micro-perforated film could prove more beneficial for mangoes packaging, as it prevented the accumulation so high levels of CO2 that can lead to off-flavors.

Biodegradable packaging films such as chitosan were found to be ideal compared with low density polyethylene (LDPE) films in retaining the overall flavor quality of the mangoes.

‘Tommy Atkins’ and ‘Keitt’ fruits could be stored for three weeks at 12 ° C when these were packed in4 kg film-lined cartons by sung micro-perforated polyethylene (PE) or Xtend film (XF). XF film was found to be very effective in reducing chilling injury and lowering the level of condensation inside the package due to lower relative humidity in the XF film (~90%) as compared to PE (~99%).

The use of bags should be avoided for packing mangoes. In addition being stackable, facilitating greater quantities per load for transportation, they offer better ventilation and greater protection against damage than bags.
Packaging for mangoes

Micro-porous film

Micro-porous films are defined as having a narrow pore-size distribution, usually in the sub-micrometer range although they can range from 0.1 to 10 um. It is common for micr0-porous films to have 1-2 billion pores per square centimeter in a film 10-50 um thick.

Modified atmosphere packaging (MAP) of fresh produce has been an active research area for many years. The problem is that most polymeric films are too impermeable for packaging high-respiring products like broccoli, cauliflower, carrots and cut fruit.

In order of achieving high rates of gas exchange is through the use of micro-porous and perforated films. The gas diffusion constant for a perforation is approximately 4 to 8 million times greater than that of a low-density polyethylene film.

Micro-porous films are prepared by extrusion of filler-containing polymers. The common fillers are CaCO2 or SiO2, although other porous powders may be included.

Gas permeability is controlled by adjusting the filler content, the particle size of the filler and the degree of stretching the film.
Micro-porous film