Wax for fruits

One of the methods to preserve fresh-fruit quality during handling and subsequent marketing can be achieved by the application of waxes on the surface of the fruit. Waxes have been use for apples, pears, citrus fruits in tomatoes. Waxes and other coatings have been applied to the surface of fresh fruits for many years to improve their appearance and reduce water loss.

Categories of wax accruing to their use:
*Storage wax: when use is not to be marketed immediately
*Pack-out wax: When fruits are to be marketed immediately
*High-shine-wax: For giving a very high grace on market demand

Waxing generally reduces the respirations and transpiration rates, but other chemicals, such as fungicides, growth regulators, preservatives, can also be incorporated especially for reducing microbial spoilage, sprout inhibition.
Wax for fruits

History of modified atmosphere packaging (MAP)

Modified atmosphere packaging can be defined as an alteration in the composition of gases in and around fresh produce by respiration and transpiration when such commodities are sealed in plastic films.

Much of original work was done in Australia and New Zealand when beef and lamb carcasses were shipped in the 1930s to the UK was stored in carbon dioxide to help maintain freshness.

During the 1940s and 1950s fresh apples and pears were placed in enclosed warehouse. The natural respiratory activities of the fruit reduced the oxygen and increased the carbon dioxide within storage areas sufficiently to slow respiration markedly.

The stored apples or pears could be consumed as much as six months after the original harvest: and extensions of about double the normal chilled storage shelf-life.

In the 1970s, modified atmosphere packages were used for some retail packs of meat and fish. The new techniques have been developed, including micro-perforation, anti-fogging layers to improve product visibility.

The use of modified atmosphere packaging technology received a significant boost when the retail chain of Marks and Spencer introduced a wide range of fresh MAD meat products in the UK in 1981.

Today, modified atmosphere packaging is used to package anything from fresh salads or individual meat portions, to sandwiches and snacks.

History of modified atmosphere packaging (MAP)

Grapes packing

In packing grapes, different types of containers are used: Lug boxes are most generally used, and the depth of the lug is varied according to a variety and consumer preference. Sawdust chest packs are used for grapes to be exported.

Grapes to be shipped as fresh are packed in wooden crates, then pre-cooled to about 40 ° F (4.4 °C) in railroad cars or refrigerated rooms.  Grapes destined for immediate delivery are sometimes shipped without pre-cooling though they should be shipped in a refrigerated container.

Grape bunches can be arranged in different ways in the containers. In the stem-up pack arrangement clusters stems are in full view but packs are attractive. Fresh grapes can be packed in this manner with very little handling injury.

Generally, the grapes will be fumigated with sulfur dioxide prior to or during cooling to prevent mold growth.

Grapes that are to be stored for future shipment should be packed in crates, pre-cooled to 36-40 °F (2.2 - 4.4 °C), place in refrigerated storage 29- 32 ° F (-1.67 – 0 °F), and fumigated with sulfur dioxide and should be held ih this manner until shipped.

Periodic re-fumigation with sulfur dioxide may be required to prevent spoilage by molds.

Most table grapes are packed as they are picked to avoid extra handling. A large part of the California grape crop is packed in the vineyard. This method has some advantages over the house-pack method:
• Less capital investment in packing facilities
• Only a vineyard crew to mange rather than a picking and lacking crew whose production must be coordinated
• No large inventory of filed lugs
Grapes packing

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