MODIFIED ATMOSPHERE PACKAGE FOR BANANAS

Abstract

There is provided an enclosure comprising: a polymeric film; wherein said polymeric film comprises one or more copolymers of ethylene with a polar monomer; and wherein the oxygen transmission rate of said enclosure is 8,000 to 16,000 cm3/hour. Also provided is a method of handling bananas comprising: (a) harvesting green bananas; (b) then placing said green bananas into such an enclosure; (c) then storing said enclosure at 20 C. or lower for 1 week or longer; (d) then ripening said bananas or allowing said bananas to ripen.

Claims

1.-5. (canceled)

6. A method of handling bananas comprising: (a) harvesting green bananas; (b) then placing said green bananas into an enclosure; (c) then storing said enclosure at 20 C. or lower for 1 week or longer; (d) then ripening said bananas or allowing said bananas to ripen, wherein the enclosure comprises a polymeric film comprising one or more copolymers of ethylene with a polar monomer; and wherein the oxygen transmission rate of the enclosure is 8,000 to 16,000 cm.sup.3/hour.

7. The method of claim 6, wherein the duration of said step (b) is 2 weeks or longer.

8. The method of claim 6, wherein said step (d) comprises exposing said enclosure to an atmosphere that contains ethylene.

9. The method of claim 6, wherein said method additionally comprises the step (e), subsequent to said step (d), of exposing said enclosure to an atmosphere that contains one or more cyclopropene compound.

10. The method of claim 6, wherein said polymeric film further comprises one or more olefin polymer.

11. The method of claim 10, wherein said polar monomer is vinyl acetate.

12. The method of claim 11, wherein the amount of polymerized units of said polar monomer is 0.05% to 18% by weight, based on the weight of said polymeric film.

Description

EXAMPLE 1: OXYGEN TRANSMISSION RATE

[0076] A variety of bags was made as described above. Width was 91.4 cm, and length was 152.4 or 165.1 cm. Some bags (labeled none) had no perforations. Other bags had perforations arranged by varying perforation spacing between 1 mm and 22 mm and thereby the number of perforations per bag between 499 and 5486.

[0077] The oxygen transmission rate of the entire bag was measured using the whole bag method, as follows. The bag was supported on a tent frame of known volume, purged with nitrogen so that the oxygen content was less than 1%, and then the concentration of oxygen was measured versus time. The rate of oxygen transmission for the system was calculated by plotting the natural log of the oxygen concentration gradient versus time as discussed by Ghosh and Anantheswaran. [Ghosh, V. and Anantheswaran, R. C. 2001. Oxygen transmission rate through micro-perforated films; measurement and model comparison. Journal of Food Process Engineering. Vol. 24. pp 113-133.]

[0078] Results were as follows:

TABLE-US-00003 Spacing (mm) Total Perforations OTR.sup.(1) 2 5486 32574 3 3658 20888 4 2,743 17266 5* 2195 14916 5.5* 1995 13593 6* 1829 11721 6.5* 1688 10916 8.5 1291 9112 9.5 1155 8408 11 998 6857 22 499 4067 none none 1064 Note .sup.(1)Oxygen Transmission Rate of the entire bag (cubic centimeter per hour). Note *Bags having 5, 5.5, 6, and 6.5 mm spacings fall within the present invention. The other bags are comparative.

EXAMPLE 2: HANDLING OF BANANAS

[0079] Bananas were harvested in Guatemala at 11-12 weeks growth. Within 3 days of harvest, bananas were placed into bags and put into storage at 14.4 C. Each bag held 18 kg of bananas. The bags tested were the bags listed in Example 1, plus Banavac (BV) bags (commercially available polyethylene bags with no perforations). No steps were taken to remove gas from any bag or to introduce any gas into any bag (other than changes in atmosphere inside the bags caused by placing bananas into the bags and changes in atmosphere inside the bags caused by diffusion through the enclosures). All bags remained closed from the time bananas were placed into the bags until the bananas were removed on day 42 for evaluation, except that half the Banavac bags were opened during ripening on day 31 and remained open for the period of study, while the rest of the Banavac bags remained closed until evaluations on day 42.

[0080] Bags were packed with bananas as follows, giving a top layer and a bottom layer. A layer of kraft paper was placed on the bottom of the box; on top of that, the open bag was placed. Two rows of fruit were placed in the center of the bag along the length of the box. The kraft layer was pulled up and over the bananas, along with the bag, with the edges overlapping to cover the fruit, forming the bottom layer. The bags were then folded over the kraft paper, forming pockets to hold the top layer fruits. Two rows of top layer fruit were arranged on either side of the box. The bag was then pulled closed above the top layers of fruit; twisted shut; and then held closed using a goose neck closure held by a rubber band; a tape closure; or some other appropriate closure device.

[0081] Subsequent handling was as follows.

TABLE-US-00004 Step Completed on Day Bananas placed into bags and then put into storage 0 at 14.4 C. Shipment by boat at 14.4 C. to Pennsylvania, USA 27 Ripening Cycle 31 Exposure to 1-MCP (1,000) 34 Storage at 25 C. 42
The ripening cycle was conducted as follows: All fruits were ripened in a fully loaded and leak test qualified commercial room. The fruits, while in the boxes as described above, were ripened in a 5 day ripening cycle, as follows. The temperatures shown are pulp temperatures; if necessary, the thermostat was lowered so that pulp temperature remained at the desired temperature despite any respiration that may be taking place in the bananas.

[0082] Day 26: 17.8 C. (64 F.), in normal air

[0083] Day 27: 17.8 C. (64 F.), ethylene at 200 ppm for 24 hours

[0084] Day 28: 17.8 C. (64 F.), room was vented for 30 minutes, and then re-sealed.

[0085] Day 29: 17.8 C. (58 F.)

[0086] Day 30: 14.4 C. (58 F.)

[0087] Day 31: 14.4 C. (58 F.)

[0088] The fruits were initially conditioned overnight at 15.5-17.7 C. prior to ethylene treatment. Gassing with ethylene (1000 ppb) was carried out for 24 hours to trigger ripening. The pulp temperatures were then raised to 17.7-18.3 C. before gradually bringing them down to 13.3-14.4 C. holding range.

[0089] Exposure to 1-MCP was conducted on the boxes containing bananas as follows: Treatment with 1000 ppb 1-MCP was carried out in the commercial room for 12 hours when the fruits were at color stage between 2.5 and 3.0. After treatment the fruits were held (including untreated control) at room temperature (approximately 20-22 C.).

[0090] On Day 42, the bananas were evaluated.

[0091] Any bags that had been torn were ignored. Only the bananas from intact bags were evaluated. The results were as follows.

Observations

[0092]

TABLE-US-00005 Spacing (mm) Observations 1 Fruit ripened on arrival and sugar spotted 2 Sweet and Firm. Fruit sugar spotted. Color Variability within each bag. 3 Sweet and Firm. Fruit sugar spotted. Color Variability within each bag. 4 Sweet and Firm. Fruit sugar spotted. Color Variability within each bag. 5* Less sweet and firm than bags with 5.5, 6, and 6.5 mm. 5.5* Very sweet and firm. 6* Very sweet and firm. 6.5* Very sweet and firm. 8.5 Top layer tasted not sweet. Alcohol flavor in bottom layer. 9.5 Top layer tasted not sweet. Alcohol flavor in bottom layer. 11 Top layer tasted not sweet. Alcohol flavor in bottom layer. 22 High alcohol flavor and bitter aftertaste. no Fruits did not ripen. Distinct off flavor. perforations BV-closed Fruits did not ripen. Distinct off flavor. BV-open Distinct off flavor. Note *Bags having 5, 5.5, 6, and 6.5 mm spacings fall within the present invention. The other bags are comparative. Only the bags with spacings of 5, 5.5, 6, and 6.5 had acceptable uniformity, appearance, and taste.

Test Results

[0093]

TABLE-US-00006 Spacing Sugar.sup.(2) Sugar.sup.(2) Color.sup.(3) Color.sup.(3) Color Firm.sup.(5) Firm.sup.(5) (mm) Top Bottom Top Bottom Diff.sup.(4) Top Bottom 2 3 2.5 6.5 6.8 0.3 1.62 1.61 3 2 2 4.5 5.5 1.0 1.40 1.40 4 1 0.1 5.0 5.5 0.5 1.67 1.66 5* 0.1 1 5.5 5.5 0 1.66 1.41 5.5* 0.1 0.1 5.25 5.25 0 1.71 1.77 6* 0.1 0.1 5.0 5.0 0 1.82 1.96 6.5* 0.5 0.1 5.0 5.0 0 1.63 1.82 8.5 0.1 0.1 4.5 5.5 0 1.82 1.65 9.5 0.1 0.1 5.0 5.5 0.5 1.76 1.83 11 1 0.1 4.5 5.5 1.0 1.75 1.71 22 1 0.1 4.5 5.0 0.5 1.75 2.13 none 0.1 0.1 3.0 3.5 0.5 2.17 2.18 BV-closed 0.1 0.1 3.0 2.5 0.5 1.61 2.14 BV-open 0.5 0.1 5.0 4.5 0.5 1.27 2.19 Note: *Bags having 5, 5.5, 6, and 6.5 mm spacings fall within the present invention. The other bags are comparative. Note: .sup.(2)Sugar Spot Rating Note: .sup.(3)Color Stage Note: .sup.(4)Difference: (Color Bottom) (Color Top) Note: .sup.(5)Firmness (Newton) Bags with spacings of 2 and 3 mm showed unacceptable sugar spots. All others were acceptable. Bags with spacing of 2 mm had too-high color ratings. Bags with no perforations and BV-closed bags had too-low color ratings. The only bags with good color scale and with zero color difference between the top layer and the bottom layer were those with spacings of 5, 5.5, 6, and 6.5. The bags having spacings of 4 mm to 11 mm had acceptable firmness; the other bags had firmness that was either too high or too low.

COMPARATIVE EXAMPLE: BAG D-40 REPORTED IN WO 2011/082059

[0094] D-40 was a gusseted bag made from a 7-layer film.

[0095] The gas transmission rate for the entire D-40 bag was found by measuring the gas transmission rates for a portion of the perforated film and then making a calculation based on the entire effective area of the bag. Gas transmission rates for the perforated films were measured using quasi-isostatic method as described by Lee et al. (Lee, D. S., Yam, K. L., Piergiovanni, L. Permeation of gas and vapor, Food Packaging Science and Technology, CRC Press, New York, N.Y., 2008, pp 100-101).

[0096] The oxygen transmission rate for the entire bag determined for the D-40 bag was 17,632 cubic centimeter per hour.

[0097] Bananas were harvested and packed using D-40 bags as follows: First, macro-perforated kraft paper was placed inside the cardboard box, as in conventional packing. The D-40 bag was then placed onto the kraft paper with the seam of the bag centered and running along the length of the box, lining the cardboard box bottom and internal walls. The bag's upper length excess was folded over the box top edges. Two rows of fruit were placed with care in the bottom portion of the bag. The kraft paper was then folded over the fruit with the bag lining the kraft paper and then two layers of fruit were placed in the top pockets. Once four rows of fruit are placed in the bag, the bag's upper length excess is twisted together, folded, and tightly twist-tied with a rubber band or sticky tape.

[0098] The following undesirable effects were observed: Due to low puncture resistance and tensile strength the bag was unable to withstand the shock and vibration impacts during transit and handling. The crown of the fruit in the top layer pierced through the bag, tearing the bag and thereby compromising the modified atmosphere of the bag. This resulted in early turn and ripening in the fruit during transit and also non-uniform ripening issues on arrival.