Sealed Polyethylene Bags Research Articles

The synthesis and defluorination of monofluoroacetate in some Dichapetalum species

Leaves from Dichapetalum toxicarium (G. Don) Baill. (Dichapetalaceae) removed from the plant and aqueous extracts prepared from the leaves of D. heudelotii (Planch. ex Oliv.) Baill. were able to synthesize monofluoroacetate from NaF. D. pallidum (Oliv.) Engl. leaves were not able to synthesize monofluoroacetate from NaF. Aqueous extracts from both D. toxicarium and D. heudelotii containing monofluoroacetate and possibly other organo-fluorine compounds were defluorinated by a micro-organism from the air. This organism was able to defluorinate fluorocitrate but not difluoroacetate or trifluoroacetate. In D. toxicarium monofluoroacetate is present in a form which is easily leached from the leaves, and which is defluorinated if the leaves are kept under herbarium conditions. The monofluoroacetate in this species is not defluorinated if the leaves are dried at 100° and stored in sealed polythene bags.

Cool storage and post-storage treatment of strawberry runners for summer planting

Winter dug strawberry runners of the cultivar Red Gauntlet were stored in sealed or ventilated polyethylene bags at -2.2�C for 63 months. After storage and before planting, runners received post storage treatments at 256�C. Crown and root growth occurred where treatment duration at 25.6�C exceeded two days. This did not adversely affect vigour in the field after planting, but did reduce fruit yield in the autumn crop. Pre-storage benomyl dusting reduced mould infection after cool storage and before planting. Crown and root growth and weight loss was reduced where runners were contained in sealed polyethylene bags, and significantly higher fruit yield was subsequently obtained from these treatments.

Reduction of brown heart in pears by absorption of ethylene from the storage atmosphere

Compounds that absorb ethylene, carbon dioxide and water were packed with Williams' Bon Chretien (Bartlet) pears held in sealed polyethylene bags. The effects of these compounds on the physiological disorder brown heart are reported. After storage at 1�C for 18 weeks, fruit stored in air or in bags with a carbon dioxide absorbent (calcium hydroxide) were in poor condition externally but were free of brown heart. All other fruit were stored in the presence of about 5 per cent carbon dioxide and were externally in excellent condition but were affected by brown heart. The use of an ethylene absorbent (potassium permanganate) reduced the mean level of ethylene from 395 �l/l to 1.5 �l/l and reduced brown heart from 68 per cent to 36 per cent (P < 0.01). The presence of calcium chloride tended (P < 0.10) to increase brown heart. The storage treatments also affected the level of six other organic volatiles in the fruit.

Storage of Green Plantains

Studies were made of green plantain behavior when stored under various conditions to develop the best method of prolonging their shelf life without affecting their overall quality and processing characteristics. Freshly harvested green plantains start to ripen in about 7 days, reaching full ripeness 2 days later, when kept under room conditions at temperature of about 85° F. When stored in refrigerated chambers, plantains from the Guayamero and Maricongo cultivara remain green for 12 days, at which time signs of chilling damage begin to appear. However, the quality of plantains stored in these refrigerated chambers at 45° and 55° F. with relative humidities of 86 to 88 percent are definitely affected. At 45° F. a marked hardening of the fruits was observed and at 55° F., signs of false ripening appeared, impairing the quality of the produce. Shelf life of green plantains may be successfully prolonged, however, when thiobendazole-treated fruits are stored in sealed polyethylene bags containing an ethylene absorbent (about 200 g. of Purafil). TBZ was used in a 200-p.p.m. concentration to control mold growth. By using these combined techniques plantains were kept perfectly green for 25 days at room temperature (85° F.) and for 55 days under refrigeration (55° F.). This method had no detrimental effect on the stored fruit, as shown by the sensory evaluations of two processed products prepared from the stored green plantains at various intervals throughout the study. Tasters rated the samples as good or superior to similar products prepared from freshly harvested green fruit.

Ancillary equipment for isolators. 1. A sealed sachet transfer unit.

An attachment allows waste and other materials, carcases, eggs and equipment to be removed in sealed polythene bags, without risk of contaminating the isolator.

Storage of gooseberries in plastic bags

SummaryStorage of gooseberries in sealed polythene bags was shown to give useful extension of fresh fruit life without detrimental effects on fruit quality. Quality was assessed by analyses for firmness, colour, acidity and reducing sugars and by tasting of random samples.At 0‐l°C over 90% of the fruit in 7 lb lots in sealed bags was sound after 8 weeks, while in the corresponding 28 lb lots the percentage of sound fruit was in the range 81–88%. Control of the atmosphere in the bags was difficult and this aspect would limit commercial application of the technique. No ethylene was detected in any of the sealed bags.

The Course of Ripening of Banana Fruits Stored in Sealed Polyethylene Bags1,2

Abstract Green, unripe banana fruits (Dwarf Cavendish) were stored in sealed polyethylene bags with and without potassium permanganate (KMnO4). Some fruits were triggered to ripen by ethylene before sealing the bags and in some of them ethylene was injected after sealing. The presence of ethylene stimulated pectin methyl esterase (PME) activity and starch hydrolysis and caused softening, but color change was inhibited by high concentrations of carbon dioxide. It is suggested that in the presence of high carbon dioxide and low oxygen concentrations, ethylene acts in different ways on the coloring and the softening processes of banana fruits.

Potassium permanganate as an ethylene absorbent in polyethylene bags to delay ripening of bananas during storage

Potassium permanganate reduced the concentration of ethylene and calcium hydroxide reduced the concentration of carbon dioxide in sealed polyethylene bags containing bananas. When the fruit that were not packed in sealed bags were ripe (16 days after the beginning of storage) all the fruit in sealed polyethylene bags were in a firm green condition and there was little difference between treatments in sealed polyethylene bags. After 29 days some of the fruit in sealed bags had softened, but fruit in bags containing potassium permanganate was firmer than fruit receiving other treatments, and this effect was more marked after 38 days. It was estimated that about two weeks additional storage life was obtained by packing potassium permanganate with the fruit.

Study on the Preservation of "TAKUANZUKE" in a Sealed Polyethylene Bag

Six species of yeasts and one species of bacteria were isolated from "TAKUANZUKE" (pickled raddish in the mash of rice bran and salt) in a polyethylene film bag in which fermentation was observed. One of the yeasts was identified as Hansenula anomala, two as Torulopsis sake and remaining three also belonged to Torulopsis group. The bacteria seemed to be lactic acid bacteria. Hansenula anomala and Torulopsis sake were not able to grow in 18% brine and the bacteria in 17% brine. Heat treatment was effective to prevent growth of the yeasts at 55°C for 30min., 60°C for 20min., 65°C for 10min. and bacteria at 50-55°C for 20min., 60°C for 10min. Sorbic acid was also effective to prevent growth of these yeasts and bacteria depending upon pH value and NaCl concentration of the growth media.

On the effect of Potassium Sorbate and Pasteurization of "TAKUANZUKE" in a sealed polyethylene bag

The effect of potassium sorbate and pasteurization for preservation of TAKUANZUKE sealed in a flexible bag was investigated to obtain the following results. When the liquid (for pickles) was sealed with the pickles, TAKUANZUKE was preserved well by the addition of potassium sorbate into the liquid at the level of 0.2% (w/v). However, when rice bran mash containing many microorganisms remained over TAKUANZUKE, addition of potassium sorbate was not satisfactory for preservation. Washing away remained rice bran mash or sterilization by chloramine T was effective. The amount of potassium sorbate in the liquid for pickles decreased as the decay developed. When the liquid was not sealed, heat processing at 65°C for min. was effective. Softening of TAKUANZUKE occurred above70°C. Decolouring of TAKUANZUKE occured in the bas sealed under atmosphericpressure, but not under vacum sealing.

Use of dihalohydrin precursors of butadiene diepoxide in the chemical modification of cotton cellulose

Dihalohydrin precursors of meso-butadiene diepoxide or d,l-isomers of butadiene diepoxides have been reacted with cotton cellulose. It has been shown that d,l-2,3-dibromo-1,4-butanediol, d,l-2,3-dichloro-1,4-butanediol, meso-2,3-dichloro-1,4-butanediol, and meso-1,4-dichloro-2,3-butanediol, can be added to cotton in small amounts (1–4%) to increase both dry and wet crease resistance of the fabric. Several methods of application were investigated, and two methods for the in situ formation of the butadiene diepoxides in cotton and their subsequent reaction with cellulosic hydroxyls rather than solvolysis have been proposed. Both processes call for the application of the dihalohydrin from an aqueous solution and subsequent treatment of the dried fabric by either of the following: (1) absolute alcoholic solution of NaOH or (2) concentrated aqueous solution of Na4SiO4 saturated with NaCl. With the former, a slow curing of the dehydrohalogenated sample in a sealed polyethylene bag at room temperature or a rapid high temperature cure could be used; with the latter, increased dry and wet crease resistance was obtained only with a rapid high temperature cure. Use of aqueous orthosilicate solutions offers a potential commercial application, since the dihalohydrins are relatively inexpensive and such a process avoids handling of the volatile and relatively toxic butadiene diepoxides. Typical fabric properties obtained with the various methods are included.

The Reaction at the Iron Alkaline Electrode

The discharged state of the iron (Edison) electrode in alkaline solution has been reported historically as a number of materials, usually as either or . Recent x‐ray crystallography data, obtained independently in the two laboratories represented by the authors, indicates the material to be or , depending on the conditions of discharge. X‐ray patterns were obtained by in situ techniques with electrodes cycled in sealed polyethylene bags, as well as with washed and dried active materials.

THE INFLUENCE OF FIELD AGING ON GAS MASK CANISTERS, ARMY TYPE M-11.

Abstract A study was made to establish whether field storage reduced the effectiveness of Army Type M-11 gas mask canisters in protecting against hydrogen fluoride. Effectiveness against HF was retained by canisters stored up to 30 months in sealed polyethylene bags, and canisters with intact rubber and metal end-seals were effective after storage up to 12 years in paper bags.

Effects of air‐drying and air‐dry storage on the mineralisable‐nitrogen of soils

AbstractSamples of eight soils were air‐dried and stored in brown‐paper or in sealed polythene bags for periods up to 98 weeks. Portions of the fresh and re‐wetted air‐dry soils were incubated at 25° for 10–84 days. the soils were extracted before and after incubation and the increase in mineral‐N (NH4+‐N + NO3−‐N) content (Δ Mineral‐N) was measured. Air‐drying increased Δ Mineral‐N. Air‐dry storage further increased Δ Mineral‐N, the value increasing with the period stored, but the mineralisable‐N of soils kept in sealed polythene bags increased less than that of soils in paper bags, the increases occurring only in the easily mineralisable‐N; most of the extra mineral‐N was formed during the first 10 days incubation and all by 42 days, thereafter the air‐dried soils had the same rate of mineralisation as the fresh soils. the mineral‐N content of the air‐dry soils increased with storage.In a further similar test with 14 soils, air‐dried and stored in brown‐paper bags for periods up to 32 weeks, the mean value of Δ Mineral‐N varied irregularly with time of storage up to 18 weeks but thereafter increased with increasing period of storage before incubation. the mineral‐N content of the air‐dry soils varied, the maximum value being found in the samples stored for 12 weeks.

Influence of temperature and relative humidity on the photographic response to Co60 γ-radiation.

At relative humidities close to a hundred percent, bare film packets are unsatisfactory for personnel dosimetry, regardless of temperature. Sealed polyethylene bags afford considerable protection from excessive humidity. (auth)