Modified atmosphere packaging for transportation and ripening of bananas and plantains with extended quality preservation
10687539 ยท 2020-06-23
Assignee
Inventors
Cpc classification
B65D85/34
PERFORMING OPERATIONS; TRANSPORTING
A23B7/148
HUMAN NECESSITIES
B65D2565/388
PERFORMING OPERATIONS; TRANSPORTING
A23B7/152
HUMAN NECESSITIES
International classification
A23B7/152
HUMAN NECESSITIES
B65D85/34
PERFORMING OPERATIONS; TRANSPORTING
B65D81/26
PERFORMING OPERATIONS; TRANSPORTING
A23B7/148
HUMAN NECESSITIES
Abstract
A packaging apparatus suitable for containing and transporting a specified quantity of bananas or plantains includes a vented box and a plastic bag that includes laser microperforations located in target areas separated from each other by distances greater than their largest dimensions. When the bag is placed within the box, filled with bananas or plantains, and hermetically sealed, the microperforations and box vents allow for limited transmission of gases into and out of the bag to establish a modified atmosphere within the bag, and to allow ethylene ripening of the bananas or plantains. The target areas are located at the top of the bag, and also at the bottom of the bag, so that they are not occluded when the bananas or plantains are placed within the bag with their concave sides facing down.
Claims
1. A packaging apparatus containing bananas or plantains, and suitable for both ripening and extending the shelf life of said bananas or plantains, the apparatus comprising: a box; a plastic bag placed within the box, said plastic bag having a bottom at a closed distal end thereof, and a sealed top at a proximal end thereof; and a plurality of bananas or plantains contained within the plastic bag and positioned having their concave sides facing down toward a bottom of the box; said plastic bag being penetrated by laser microperforations located only in a distributed plurality of target areas on the plastic bag, each of said target areas including a plurality of said microperforations, each of said target areas being separated from all neighboring target areas by distances that are greater than the target area's largest dimension, each of said microperforations having an average diameter of between 100 microns and 400 microns; said target areas including target areas located at both the bottom and the top of the plastic bag, wherein the target areas at the bottom of the plastic bag are provided in locations that are not occluded by said bananas or plantains; and each of said target areas being an array of the microperforations.
2. The apparatus according to claim 1, wherein the bag material is selected from the group of plastics consisting of polyethylene, polypropylene, polyester, nylon, polystyrene, polyvinyl chloride, polylactic acid in monolayers, coextrusions, and laminates.
3. The apparatus of claim 1, wherein the proximal end of the bag is hermetically sealed by gathering together a proximal portion of the bag, twisting the gathered portion into a neck folding over the neck, and securing the neck.
4. The apparatus according to claim 1, wherein there are 4 or 6 target areas on the bag.
5. The apparatus of claim 1, wherein the bag has a front side and a back side, and there are at least three target areas on the front side of the bag and in at least three target areas on the back side of the bag.
6. The apparatus of claim 1, wherein the box and bag contain 40 lb of bananas, and the target areas include a target area located approximately 2 from the distal end of the bag, and a target area located approximately 26 from the distal end of the bag.
7. The apparatus according to claim 1, wherein each of said microperforations has an average diameter of between 150 microns and 235 microns.
8. The apparatus of claim 1, wherein the box and bag contain 50 lb of plantains and the target areas include a target area located approximately 1 from the distal end of the bag, and a target area located approximately 17 from the bottom seal of the bag.
9. The apparatus of claim 8, wherein the microperforation size is 225-230 microns.
10. The apparatus of claim 1, wherein the microperforations are of sufficient size and number to allow a total O.sub.2 flux for the packed bananas to be within a range of 1000 cc/day-atm to 500,000 cc/day-atm.
11. The apparatus of claim 1, wherein the box and bag contain 3 lb of bananas or plantains.
12. The apparatus of claim 1, wherein the box includes upper vents proximal to a top thereof and lower vents proximal to a bottom thereof; and the plastic bag is inserted in the box so as to align at least some of the target areas of the bag with corresponding vents in the box.
13. A packaging apparatus containing 40 lbs of bananas or plantains, and suitable for both ripening and extending the shelf life of said bananas or plantains, the apparatus comprising: a box having upper vents proximal to a top thereof and lower vents proximal to a bottom thereof; a plastic bag placed within the box, said plastic bag having a sealed bottom and a closed upper end; and, 40 lbs. of bananas or plantains contained within the plastic bag and positioned with their concave sides facing down toward the bottom of the box said plastic bag being laser microperforated in at least one upper target area on a front side thereof 26 up from a bottom seal thereof, at least one upper target area on a back side thereof 26 up from the sealed bottom thereof, at least one lower target area on the front side thereof 2 up from the sealed bottom thereof, and at least one lower target area on the back side thereof 2 up from the sealed bottom thereof, each of said target areas including a plurality of microperforations, each of said target areas being separated from all neighboring target areas by distances that are greater than a largest size of the target area, each of said laser microperforations having an average diameter of between 150 microns and 235 microns, and each of said target areas being an array of the microperforations, said target areas being the only perforations on the bag; said plastic bag being hermetically sealed by gathering together a portion of the bag, twisting the gathered portion into a neck folding the neck over on itself, and sealing the neck with a rubber band.
14. A packaging apparatus containing bananas or plantains, and suitable for both ripening and extending the shelf life of said bananas or plantains, the apparatus comprising: a box; a plastic bag having a bottom at a sealed distal end thereof, and a closed top at a proximal end thereof; and a plurality of bananas or plantains contained within the plastic bag and positioned with their concave sides facing down toward a bottom of the box; said plastic bag including laser microperforating located only in target areas, said target areas including at least one upper target area located at the top of the bag on a front side thereof, at least one upper target area located at the top of the bag on a back side thereof, at least one lower target area located at the bottom of the bag on the front side thereof, and at least one lower target area located at the bottom of the bag on the back side thereof, each of said target areas including a plurality of microperforations, each of said upper and lower target areas on the front side of the plastic bag being separated from each other by at least 16 inches, each of said upper and lower target areas on the back side of the plastic bag being separated from each other by at least 16 inches, each of said microperforations having an average diameter of between 100 microns and 400 microns, and each of said target areas being an array of the microperforations.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings in which:
(2)
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(4)
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DETAILED DESCRIPTION
(7) Currently available technology for banana and plantain packaging provides solutions that are either expensive (microporous membrane technology) or insufficient to meet the specific needs related to fruit ripening (Banavac bags or Tubopac bags). Therefore, this disclosure addresses these problems and the invention according to this disclosure provides a method to pack bananas and plantains, a method to extend the green life and the shelf life of bananas and plantains, and a method to improve the quality of the bananas and plantains.
Definitions
(8) Green life is defined as the period of time from harvest until ripening is induced (naturally or artificially).
(9) Shelf life of bananas is defined as the time, after ethylene treatment, until the banana peel shows sugar spots (color stage 7).
(10) Banana and plantain color is described in stages by the industry. A color stage of 3.5 to 5 is preferred for bananas placed on sale at retail. At color stage 3, bananas and plantains are 50% yellow and 50% green. At a color stage of 5, bananas and plantains are 95% yellow with slight green color at stem and blossom end.
(11) Registered microperforation means laser perforations registered in a well-defined area(s) of the package. Each microperforation has a preferred average diameter between 110 and 400 microns, and more preferably for bananas between 150-235 microns.
(12) In this disclosure, the units applied to the term used in reference to the O.sub.2, transmission rates of a packaging material, i.e., OTR is expressed as cc/m.sup.2-day-atmosphere (or cc/100 in.sup.2-day-atm) at 25 C., 75% RH. In the pressure units, one atmosphere (atm) is 101,325 kg/ms.sup.2. Another unit describing the flow of a particular gas through a packaging material is Flux, expressed as cc/day-atm. The Total O.sub.2 Flux of a microperforated package is the sum of the O.sub.2 Flux of the base material (e.g. polyethylene) and the O.sub.2 Flux of the microperforations. The moisture vapor transmission rate (MVTR) of a material is expressed as g H.sub.2O/m.sup.2-day-atm or g/100 in.sup.2-day-atm.
(13) The invention is now illustrated further by non-limiting examples.
Example 1: Registered Microperforations Provide a Package that does not have to be Ripped Open to Initiate the Ripening Cycle
(14) A small scale study was conducted on packaged 40-lb bananas sealed in registered microperforated bags. The 1.0 mil polyethylene (PE) bags were 40.5 wide and 48.5 long. The bag material can also be selected from polypropylene, polyester, nylon, polystyrene, polyvinyl chloride, polylactic acid in monolayers, coextrusions, and laminates. Microperforations (225 microns in diameter) were drilled into the front and back panels of the bags and were registered at 11.5 down from the open end and 19.5 from either side. The total O.sub.2 flux of the bag (base PE film+microperforations) was 61,283 cc/day-atm. The objective was to monitor the gas composition inside the bags during simulated ship transport (3 weeks at 14 C) and after gassing with ethylene for 24 hrs.
(15)
(16) Concomitant with the surge of ethylene into the bags, respiration rate of the bananas increases as evidenced by the decrease in O.sub.2 and increase in CO.sub.2 levels inside the bags. During this ripening process O.sub.2 levels dropped to 5-6% and CO.sub.2 levels rose as high as 14%. These reduced O.sub.2 levels and elevated CO.sub.2 levels will slow ripening rates and account for slower color development in bananas stored in modified atmospheres compared to those stored in ambient air.
Example 2: Green Life of Bananas can be Increased and Ripening Delayed by Packing in Registered Microperforated Bag
(17) In order to test whether packing bananas in registered microperforated bags would increase the green life and delay ripening we conducted this test and compared effects of three package types. Forty-lb boxes of green bananas packed in one of three types of bags were held at 18 C. The bag types were Polypack bag, Banavac bag and Registered microperforated bag with one location of microperforations per side. Microperforations were drilled into PE bags (40.5 wide48.5 L1 mil thick), registering the microperforations 17 down from the open end and 19.5 from the side. Front and back panels of the bags had the same number and placement of microperforations. Registered microperforated bags tested were one of two total O.sub.2 fluxes: 47,844 cc/day-atm (referred to at RMP1) and 59,805 cc/day-atm (referred to as RMP2). The two different O.sub.2 fluxes were made by varying the number and/or size of the microperforations drilled into the PE, with the average size of microperforations being 225 microns.
(18) The time required for the first cluster to ripen was recorded. This time was considered the end of green life for those bananas. Table 1 shows the green life (days) for bananas packed in Polypack, Banavac, and registered microperforated bags.
(19) TABLE-US-00001 TABLE 1 Green life of bananas packed in different bags. Average Green Green Life Bag Type Life (days) Range (days) Polypack 21 14-26 Banavac 47 32-59 Registered 33 27-38 Microperforated Bags
(20) Banana green life and banana shelf life are two competing physiological conditions. By drastically decreasing the oxygen content in the bag, as the Banavac bag does, green life is greatly increased; 26 days over bananas held in ambient air (Polypack bags) (Table 1). However, unless the Banavac bags are torn open, the bananas will not ripen. In contrast, bananas sealed in registered microperforated bags showed an increase in green life by 12 days (up to 57% increase) compared to Polypack bananas. Bananas in RMP1 and RMP2 bags gave similar green lives.
(21) Unlike unopened bananas in Banavac bags, during the ripening cycle (ethylene gas treatment) bananas in the sealed microperforated bags carried on normal ripening to a color stage of 3.5 without opening the bags while Polypack bags reached a color stage of 4.5 in the same time period as can be seen in
(22) When the gassed bananas were held at 22 C. to simulate storage conditions at the retail store, bananas in Banavac bags did not ripen at all. In fact, Banavac bananas produced soft green bananas after 4 days. Polypack bananas reached a color stage of 7 after 4 days post-ripening, compared to bananas in registered microperforated bags which changed to a color stage of 5 after days. Therefore, post-ripening studies show that registered microperforated bags delay ripening, increasing the shelf life of bananas compared to Polypack and Banavac bags.
Example 3: Shipping Test Shows that Microperforations Become Occluded During Pack-Out Procedures
(23) Based on the results of the laboratory tests of Examples 1 and 2 above, we designed a shipping test to compare the effects of packing bananas in registered microperforated bags (one microperforation location) versus packing them in Polypack bags. The PE bag composition, dimensions, microperforation number and registration location and the total O.sub.2 flux of the bags were the same as given in Example 1 above.
(24) Four pallets of each bag type were packed out in South America and shipped to a U. S. port for evaluation. Once the bananas arrived at the port, they were placed in ethylene gassing chambers and gassed for 24 hrs and then placed in storage rooms at 14.4 C. for 8 days.
(25) Table 2 shows the gas contents inside the various packages and the color range developed by bananas in those packages 8 days after gassing. There was a wide variability in the oxygen and carbon dioxide contents inside microperforated bags, suggesting that the microperforations were occluded in some bags during the pack-out procedures.
(26) TABLE-US-00002 TABLE 2 Headspace gas content and color development in 40-lb banana bags 8 days after gassing with ethylene. Box # % 02/% CO2 Color Range After 8 days 1 12.9/5.7 4.0-5.0 2 0.5/10.3 2.0-2.5 3 2.2/10.4 2.0-2.5 4 1.2/10.0 2.5-3.0 5 1.4/10.2 2.5-3.0 6 0.7/10.2 2.0-4.0 7 6.2/8.6 2.0-3.0 8 0.9/9.9 2.5-4.0 9 5.6/9.1 3.5-4.0 10 1.3/9.3 2.0-2.5 11 0.5/10.2 2.0-2.5 Control Ambient air 5.0-5.5 Control Ambient air 5.0-5.5 Control Ambient air 5.5-6.0
(27) When the oxygen and carbon dioxide contents inside microperforated bags were 12.9 and 5.7%, respectively, the banana color range was 4.0-5.0 which is 1 to 1.5 units lower than the range for banana in control bags. The controls were at a color stage of 5.5 to 6.0. Such reduction in color stage development by the test bags is desirable if these values are consistent. However, microperforated bags with oxygen contents of 1% or less and carbon dioxide contents of 8% or more, produced bananas with color ranges of 2.0 to 2.5, and some bags with carbon dioxide values greater than 10% produced soft green fruit, an undesirable situation. Again, the data suggested that the microperforations were occluded during pack-out.
Example 4: Location of Microperforations on the Banana Bag Affects Color Development
(28) In order to solve the problems indicated in the previous example we conducted several studies to determine the effect of microperforation location on banana color development. All bags tested had the same oxygen flux, but different microperforation locations. In some bags, the microperforations were located in one location near the top center of the bag and on both front and back panels. In other bags, microperforations were placed in two locations near the bottom of the bag which would correspond to the location of the side vent holes in the carton. Bananas packed in these bags were held for two weeks at 14.4 C. before exposing to ethylene gas ripening cycle of five days. As was demonstrated before, bananas inside microperforated bags had a color of 2.5 to 3 after the ripening cycle compared to a color of about 4 for Polypack bags and opened Banavac bags. This demonstrated, once more, that the microperforations allowed ethylene gas to penetrate the bags and initiate ripening, although the ripening was delayed compared to controls. Furthermore, Table 3 shows that fruit in microperforated bags developed color more slowly during after-gassing storage studies at 18 C. Polypack and Banavac bananas (after the Banavac bags were ripped open so ripening could occur) changed from a color of 4 to 5 after 1 day to a color of 6 after 6 days at 18 C. Bananas in bags with one microperforation location at the top of the bag had a wide range of colors stages (3.5 to 5 after 6 days), while bananas in bags with two microperforation locations placed at the bottom of the bag near the carton vent holes showed more uniform color development, with colors of 3.5-4.0, than bananas in bags with one microperforation location. In all microperforated bags, shelf life was increased compared to bananas in Polypack and Banavac bags.
(29) TABLE-US-00003 TABLE 3 Color development in banana clusters 1, 4 and 6 days after gassing with ethylene. % CLUSTER BAG TYPE DAY CLUSTERS COLOR Polypack 1 61% 4.0-5.0 4 81% 5.0-5.5 6 64% 6.0 Banavac 1 50% 4.5 4 48% 5.5 6 60% 6.0 RMP*Bags1 1 48% 3.0 microperf 4 51% 3.0-5.0 location/side at the 6 58% 3.5-5.0 top RMP* Bags 1 63% 3.0 2 microperf 4 60% 3.5 locations/side at the 6 85% 3.5-4.0 bottom of the bag at the bottom *Registered Microperforated Bag
(30) The need for more than one microperforation location in banana bags was demonstrated in another ship test of 40-lb bananas packaged in S. A. and shipped to the U.S. Whenever the microperforations were located only in the bottom of the bag, the bananas in the bottom portion of the bag (after the ripening cycle) developed desirable color stages while the bananas at the top of the bag (in the same box) remained green. Conversely, when the microperforations were located only at the top of the bag, the bananas at the top developed desirable color stages while those at the bottom remained green. However, with two microperforation arrays per side in the bags, one at the top and one at the bottom, more uniform color development occurred throughout the bag.
(31) When packing the bananas in boxes the bag must be carefully placed in the box so that the microperforation zone will be aligned with the vents in the bottom and top of the box. Importantly, boxes where bananas are packed in bags according to this invention can be stored on pallet for up to two days, because the modified atmosphere in the bags slows the metabolic rate of the bananas and thus reduces generation of heat. In contrast, boxes with bananas in Banavac bags must be de-palletized and air-stacked because the heat released by the ripening fruit inside the Banavac bag causes the fruit to become soft.
(32) In order to minimize risk of breaking (puncturing) the microperforated bag, and to provide cushioning for the bananas, the following method was found preferable for packing: A heavy weight piece of paper (tunnel pad) is placed in the bottom of the box followed by the plastic bag.
(33) The tunnel pad is perforated in the area that is placed over the vent hole in the bottom of the box. Banana clusters (concave side down) are arranged in the box in four rows of approximately five clusters per row. The first row is set next to one of the long sides of the box, which allows room for the second row to be put on top of the first row but offset to the opposite long side of the box. The plastic bag is pulled up and over the tunnel pad and this triple layer of packing material is folded over the first two rows of fruit. This folding creates a pocket to hold the third row of fruit as well as creating a cushion that reduces bruising. Similarly, the bag and tunnel pad are pulled over the second and third rows of fruit to create a pocket into which the fourth row of fruit is packed. The remaining bag material is gathered together and pushed through the vent hole in the box lid as the upper half of the box is slipped over the lower half. Air is extracted from the bag with a vacuum cleaner; the bag is twisted, folded over on itself and wrapped several times with a strong rubber band to seal it.
Example 5: Importance of Leak-Free (Hermetic) Seals in Maintaining Desired Gas Atmospheres Inside Banana Bags
(34) It is important to have hermetic seals in packaged bananas to attain consistent control of the atmosphere inside. Variable leakage rate at the seal or through punctures in the bags produces variable results. In this study with 3-lb microperforated banana bags, we found that the method used to close the bag greatly affected the O.sub.2 and CO.sub.2 contents inside the bags (Table 4). Bags that were tape-closed using a pressure sensitive adhesive-coated plastic tape, produced mainly leaky bags with O.sub.2 levels averaging 17%. In contrast, a rubber-band closure technique where the neck of the bag is twisted, folded over, and secured with a rubber band yielded an average O.sub.2 content of 14%. Clearly, better control of the atmosphere inside the package was achieved by executing a tight (hermetic) seal using the rubber band technique. Hermetic bag seals can be attained by a number of other methods besides a rubber-band closure technique described here. For example, heat-sealing the bag will provide a hermetic seal.
(35) TABLE-US-00004 TABLE 4 Effect of bag closure method on headspace gas contents (at 13.3 C.) inside 3-lb microperforated banana bags before ethylene gassing. Tape Closure Rubber Band Closure O.sub.2 CO.sub.2 O.sub.2 CO.sub.2 15.6 1.4 15.4 1.5 17.6 0.3 15.0 1.8 17.8 0.2 14.7 2.5 18.1 0.2 13.9 2.1 16.4 1.1 14.3 2.1 16.3 1.2 14.6 2.1 16.0 1.2 9.7 2.3 16.5 1.1 12.4 2.5 17.2 0.4 15.0 2.0 18.8 0.1 15.1 1.9 Mean std. dev. Mean std. dev 17.0 1.0 1.8 0.5 14.0 1.7 2.1 0.3
Example 6: Effects on Ripening and Shelf Life, and Unexpected Effect of Microperforations on Crown Mold and Pedicel Withering
(36) Ship Test: Tubopak v. Registered Microperforated Bags for 40 lb Bananas. The objective of this study was to determine the effects of bag type (registered microperforated v. Tubopack) on the quality of 40 lb bananas, before gassing and after gassing. Tubopack bags have 84, diameter holes. Polyethylene bags (1.5 mil, 38.5 wide50.5 long) were laser microperforated with 225-230 micron holes in specific areas on the bag as depicted in
(37) Once the microperforated bags were filled with bananas and the bag was intertwined among the different layers of bananas, the bags were sealed by first gathering all comers of the bag together, twisting them into a neck, folding over the neck, and securing with a rubber band.
(38) Headspace Analysis on Bananas before Gassing:
(39) The bananas arrived at a California port and were discharged within 1 to 2 days. Headspace (O.sub.2/CO.sub.2) readings were taken on registered microperforated bags approximately 9 days after the bananas' arrival to the port. The bananas were stored at 13.3 C. before measuring the gas contents inside the bag headspace. Headspace analysis (O.sub.2 and CO.sub.2 contents) was done on boxes on two different pallets.
(40) TABLE-US-00005 TABLE 5 Headspace gas readings (at 13.3 C.) in registered microperforated bag containing 40-lb bananas (before ethylene treatment) Location of Box on Pallet Headspace % 02/% C02 4M (front) 15.6/5.9 4L (back) 15.7/5.8 4L (front) 16.3/5.5 5R (back) 16.4/6.1 5R (front) 15.1/6.3 5M (back) 15.5/5.8 5M (front) 15.7/5.6 5L (back) 16.7/5.3 5L (front) 15.1/6.3 6R (back) 15.5/6.3 6R (front) 16.0/5.5 6M (back) 16.5/4.5 6M (front) 13.8/6.8 6L (back) 16.6/4.9 6L (front) 16.5/5.6 7R (back) 16.3/5.0 7R (front) 14.9/6.7 7M (fback) 16.7/5.5 7M (front) 15.4/6.2 7L (back) 16.1/6.1
(41) Table 5 shows the O.sub.2 and CO.sub.2 content of boxes packed with bananas in microperforated bags before gassing. The readings were very consistent with O.sub.2 levels around 16% and CO.sub.2 levels between 5% and 7% before gassing with ethylene.
(42) After opening representative control and registered microperforated banana bags, we observed that bananas in the registered microperforated bags maintained moisture levels better than bananas in the Tubopack bags. Tubopack bags caused significant moisture loss, and this was expected since they have 84, diameter holes. Banavac bags don't have holes so they would maintain the moisture content. However, they undoubtedly retain too much moisture inside the bag which could lead to crown mold. The moisture vapor transmission rate (MVTR) of the microperforated bags is far greater than that of the Banavac bag. MVTRs of a 1 mil HDPE Banavac bag is less than 1 g H.sub.2O/100 in.sup.2-day while the MVTR of microperforated bags is in excess of 100 g H.sub.2O/100 in.sup.2-day, regardless of bag thickness. Obviously, water vapor can ready pass through the microperforations to reduce the concentration of moisture inside the bag. At the same size hole, the more microperforations, the higher the MVTR. The key is to allow some moisture vapor escape to reduce the growth of mold, but at the same time maintain enough moisture inside the bag to prevent dehydration.
(43) Headspace Analysis on Bananas after Gassing: Bananas were gassed for 24 hours, at 15.5 C, and headspace readings were taken. Again, readings were taken from boxes on two different pallets.
(44) TABLE-US-00006 TABLE 6 Headspace gas readings (at 15.50 C.) in registered microperforated bags containing 40 lb bananas (after ethylene treatment) Location of Box on Pallet Headspace % O.sub.2/% CO.sub.2 1R (Back) 4.9/21.5 1R (front) 12.8/10.3 1M (back) 3.5/22.3 1M (front) 12.7/11.4 1L (back) 4.1/28.0 1L (front) 11.4/13.4 2R (back) 1.5/23.5 2R (front) 7.2/17.5 2M (back) 2.9/22.8 2M (front) 6.1/19.0 2L (back) 3.0/23.8 2L (front) 5.8/21.2 3R (back) 7.8/15.1 3R (front) 4.8/20.9 3M (back) 3.6/21.3 3M (front) 17.4/3.7 3L (back) 4.8/19.7 3L (front) 2.9/21.5 4R (back) 3.7/22.3 4R (front) 4.5/21.7
(45) Table 6 shows O.sub.2 and CO.sub.2 levels inside the 40-lb microperforated banana bags after gassing with ethylene. The levels of O.sub.2 varied from <1% to 17% with most readings between 3% and 5%. The few unusually high O.sub.2 reading may be due to a poor seal, resulting in an increased flux of O.sub.2 into the bag. Those readings with O.sub.2 less than 1% may be due to microperforation occlusion.
(46) The levels of CO.sub.2 varied from 4% to 24% with the majority of the reading between 20% and 23%. We would expect to see a reduction in O.sub.2 levels and an increase in CO.sub.2 levels after gassing, because ethylene increases the respiration rate of the bananas.
(47) It appears that, in this study most of the seals were good, because they were secured with a rubber band.
(48) After gassing, the bananas in registered microperforated bags were approximately 1.5 stages behind the control (Tubopack) bananas. Bananas packaged in registered microperforated bags were not as ripe as controls, averaging a color stage of 2.5 to 3. In addition, bananas in registered microperforated bags were more uniform in color than control bananas which averaged 3 to 5 color stage (Tables 7 and 8).
(49) More moisture was maintained inside the registered microperforated bags than with the Tubopack bags, and this, undoubtedly, may have helped to prevent withered pedicels during storage (Tables 7 and 8). Bananas in registered microperforated bags showed no withered pedicels while controls averaged 9-11% withered pedicels in the light, moderate and severe ranges.
(50) Based on the data collected during this ship test, the use of registered microperforated bags with microperforations in four locations (2 in front and 2 in back) helped to eliminate the non-uniformity of ripening that was observed when only two microperforation locations were used. The twist and tie rubber band closure technique eliminated many of the leakers that were observed with tape closures. Compared to Tubopack control bags, the benefits of controlling the atmosphere using registered microperforated bags include: a reduction in the rate of color development, a reduction in moisture loss, and a reduction in crown mold and pedicel withering
(51) TABLE-US-00007 TABLE 7 Banana quality in Registered Microperforated Bags after gassing Crown Mold (%) Withered Pedicels (%) Sample OCA Clusters L M S L M S Color Latex 1 2.8 18.0 0.0 0.0 0.0 0.0 0.0 0.0 2.5 33.3 2 2.6 19.0 0.0 0.0 0.0 0.0 0.0 0.0 2.5 10.5 3 2.5 17.0 0.0 0.0 0.0 0.0 0.0 0.0 2.5-3.0 17.6 4 2.5 17.0 0.0 0.0 0.0 0.0 0.0 0.0 2.5-3.0 41.2 Average 2.60 17.8 0.0 0.0 0.0 0.0 0.0 0.0 2.5-3.0 25.4 L: Light, M: Moderate; S: Severe
(52) TABLE-US-00008 TABLE 8 Banana quality in Tubopack (control) after gassing Crown Mold (%) Withered Pedicels (%) Sample OCA Clusters L M S L M S Color Latex 1 3.0 16.0 31.3 6.3 18.8 12.5 6.3 12.5 3-5 43.8 2 2.5 17.0 23.5 11.8 29.4 5.9 17.6 11.8 3-5 23.5 3 3.2 15.0 20.0 20.0 46.7 13.3 20.0 13.3 3-6 33.3 4 2.8 16.0 25.0 12.5 0.0 12.5 0.0 0.0 3-5 25.0 Average 2.88 16.0 25.0 12.5 23.4 10.9 10.9 9.4 3-5 31.3
Example 7: Effects of More than Two Microperforation Locations in Banana Bags on Uniformity of Banana Ripening
(53) The effects on uniformity of banana ripening of including more than 2 microperforation locations per bag side was studied in a large ship test from South America. Forty-lb banana bags (1.5 mil PE, 38.5 wide48 L) were microperforated with 225 micron holes at 4 locations in the front panel and 4 locations in the back panel. The total 02 flux of these bags was the same as the bags in Example 6 above, i.e., 82,294 cc/day-atm. However, the total flux was divided into 4 microperforation locations/side rather than 2/side as in the previous example,
(54) Using 4 microperforation locations/side improved the uniformity of banana ripening compared to only 2 microperforation locations/side. Bananas in bags with two microperforation locations/side showed color stages from 2.5-4.0 after ethylene ripening (Table 9). In contrast, bananas in bags with 4 microperforation locations/side showed a narrower color range of 3.0-4.0 after ripening. The data also show that color development during storage at room temperature was delayed by 1 to 1.5 stages for bananas packaged in microperforated bags compared to control packaged (Tubopack) bananas. Furthermore, bananas packaged in microperforated bags, unlike those packed in Tubopack bags, did not show dehydration, crown rot, yellow crown and withered pedicels during storage, indicating an improved shelf life for bananas stored in microperforated bags.
(55) TABLE-US-00009 TABLE 9 Banana color after ripening and storage at room temperature Days after ripening Bag Type 0 1 2 3 4 Tubopack (SOP) 4.0 (Range = 3-5) 5.0 5.5 6.5 MP-2 locations 3.0 (2.5-4.0) 3.5 4.0 5.0 6.5 MP-4 locations 3.5 (3.0-4.0) 4.0 4.5 5.5 7.0 *Note: Dehydration, crown rot, yellow crown and withered pedicel were observed in SOP bag but not in the MP (microperforated) bags
Example 8: The Weight of Bananas to be Enclosed in the Bag Determines the Number of Microperforations in the Bag and Microperforation Locations
(56) For some retail applications, it may be desirable to market a single banana (a finger) enclosed inside a small microperforated bag. The number of microperforations needed to control the quality of a single banana in a bag is far less than required by 40-lbs of bananas in a bag.
(57) A study was conducted to determine if registered microperforated bags would be useful in controlling the quality of single bananas in a 1.25 mil PE bag 3 wide11.25 long. Four, 150-micron microperforations were drilled into each side of the bag at a location of 5 up from the bottom seal. The total O.sub.2 Flux of the bag was 1920 cc/day-atm. Naked (no packaging) single finger bananas showed a color stage of 5.0 after the ripening cycle (Day 0) compared to a color stage of 4.0 for those packaged in the microperforated bag (Table 10). In addition, there was delayed color development for bananas packaged in the microperforated bag compared to the naked bananas after 2 and 4 days storage at room temperature. Therefore, the microperforated bags extended the shelf life of the single finger bananas compared to no packaging.
(58) TABLE-US-00010 TABLE 10 Banana color after opening and storage at room temperature Days after ripening Type of Packaging 0 1 2 3 4 No Packaging- Naked 5.0 6.5 Single Finger Banana Single Finger Banana 4.0 5.0 6.5
Example 9: Plantain Fruits Ripen Uniformly in 50-Lb Microperforated Bags
(59) Green plantain fruits were packed in microperforated bags designed for 50 lb of plantains. The bag material was 1.5 mil thick PE Blend with an oxygen transmission rate of 350 cc 02/100 in.sup.2 day-atm. Bag dimensions were 38 wide and 35 long. Each bag had four positions of microperforations on each side of the bag.
(60) Two set of microperforations were drilled into the front and back panels of the plantain bag at the following locations: 1 up and 17 up from the bottom seal of the bag and 12.5 from each bag side (
(61) With the appropriate microperforation number and placement, plantain fruits ripened uniformly in these hermetically closed bags to color stage 3-4. Plantains in registered microperforated bags did not show crown rot, yellow crown or withered pedicels during storage, indicating an improved shelf life for plantains stored in microperforated bags.
(62) The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. Each and every page of this submission, and all contents thereon, however characterized, identified, or numbered, is considered a substantive part of this application for all purposes, irrespective of form or placement within the application. This specification is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure.
(63) Although the present application is shown in a limited number of forms, the scope of the invention is not limited to just these forms, but is amenable to various changes and modifications without departing from the spirit thereof. The disclosure presented herein does not explicitly disclose all possible combinations of features that fall within the scope of the invention. The features disclosed herein for the various embodiments can generally be interchanged and combined into any combinations that are not self-contradictory without departing from the scope of the invention. In particular, the limitations presented in dependent claims below can be combined with their corresponding independent claims in any number and in any order without departing from the scope of this disclosure, unless the dependent claims are logically incompatible with each other.