Cold storage

In order to keep fruit fresh, the ripening is slowed down by cold storage (cf. 18.1.5) and/or with additives which inhibit the formation or action of ethylene. 

As a result of structural similarities, MCP docks on to receptor proteins for ethylene, causing it to lose activity. The texture and color of apples and pears (sensitive varieties) do not change through months of cool storage. The sugar content also remains constant while the acid content increases. Gaseous MCP adsorbed on dextran is used for the treatment of fruit. The MCP is liberated by the addition of water. The concentrations applied are in the range 300-1000 ppb. 

The poly amines putrescine (butane-1,4-diamine), spermidine [N-(3-aminopropyl)butane-1,4-diamine] and spermine [N,N -bis-(3-aminopropyl)- 

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Diphenylamine inhibits the development of scald disease during prolonged cold storage of apples and pears (42—45). It prolongs the fresh appearance of cut snapdragons (46), controls weather fleck in tobacco, inhibits algae formation, and shows growth inhibitory activity in potatoes (47). 

As CFG refrigerants are phased out of production, their replacements in the cold storage appHcations will be HFC candidates such as R-134a, R-404A, and R-507. The use of ammonia, which is considered an environmentally benign refrigerant, will continue to play an ever-increasing role. 

The TYZOR AA, which is a 75% isopropyl alcohol solution, is unstable in cold storage. The titanate complex precipitates from solution and causes handling difficulties. The addition of small amounts (0.05—0.15 mol water/mol titanate) of water gives a solution, TYZOR AA75, that is stable in cold-temperature storage (95). 

The solvent-free mono- -butyl, monoisopropyl bis-acetylacetone titanate, TYZOR AA95 [9728-09-9] is a Hquid at room temperature. By carefully controlling the mixture of alcohols used as solvent, a product, TYZOR GBA can be obtained, which is cold-storage-stable even in the presence of nucleating agents (96). 

P-Ketoester Chelates. p-Ketoesters react in a fashion similar to the p-diketones. TYZOR DC [27858-32-8] is the hght-yeUow Hquid from TYZOR TPT and two moles of ethyl acetoacetate (eaa) after removal of the isopropyl alcohol. TYZOR BEAT, the bis-ethylacetoacetate [20753-28-0] derived from the tetra- -butyl titanate, and TYZOR IBAY [83877-91-2] the isobutoxy analogue, perform similarly to TYZOR DC. Both, however, have better cold-storage stabiHty. 

Beginning with a mixture of tetraalkyl titanates, the resultant bis-ethyl acetoacetate contains a mixture of all possible combinations of alkoxy groups, resulting in a reduction in viscosity and improved cold-storage stabiHty of the product (97). 

Many industrial workplaces are located in cold environments, such as cold storage, meat packing areas, and outdoor sites. In cold environments, clothing is the... 

Lager-bestMndigkeit, /. stability in storage, -bock, m. Mach.) pedestal. -buchse, -biichse,/. Mach.) bush, bushing, -butter, /. cold-storage butter. 

Absolute prevention of line freezing can be obtained only when the dew point of the line air is below any temperature to which it may be exposed. Freezing is always possible if there is line condensation. For example when air lines are run outdoors in winter weather or pass through cold storage rooms, the ambient temperatures will change the dew point and cause any moisture in the air to condense and freeze. 

Cold storage packing must contain and protect the product, while allowing the passage of cooling air to keep an even temperature. 

Most cold storage installations will have a wide variety of products to hold, with several different types in each chamber. Apart from... 

As a general principle, products leaving cold storage for ultimate consumption may be allowed to rise slightly in temperature but, if so, must not be re-cooled. It follows that they should be kept at the storage temperature as long as possible down the chain of delivery This requires prompt handling and the use of cooled vehicles up to the final retail outlet. 

Refrigeration is required for the cold storage rooms and to provide chilled water for the plate heat exchangers. The cellars are very wet areas, and the cooling plant should be designed to maintain as low a humidity as possible, to help preserve the building structure. 

The transport of cooled produce, using mechanical refrigeration, was one of the first major uses, dating back to 1880 and only 20 years after the first static cold storage. The present annual movement of refrigerated produce exceeds 50 million tonnes. 

Fourier Transform Infra Red Spectroscopy, Arrhenius plots of rate vs. temperature of a membrane-linked phenomenon) that biological membranes from nonhibemat-ing or cold acclimated animals show a phase transition around 12 °C to 17 °C. Thus, at useful cold storage temperatures, it is expected that the plasma membrane and membranes of the cellular organelles will be mostly in a gel or solid state. 

Another widespread application of cold storage of tissue for transplantation is that of preservation of the cornea. Inj uries leading to corneal scarring, various kinds of diseases, and the production of comeal opacity are leading causes of blindness. Cornea transplantation is a commonly used and highly successful procedure. It... 

There has been an increase in the use of cadaveric heart valves for patients with valvular defects. The valves are best stored by freezing but some success has been achieved by simple cold storage in an antibiotic medium made up of ingredients common to most tissue culture solutions. At a storage temperature of 4 °C there is a continual loss of viability of fibroblasts so that by three weeks there are practically no viable cells and the valves cannot be used. 

Belzer, F.O. Southard, J.H. (1988), Principles of solid-organ preservation by cold storage. Transplant 45, 673-676. 

Serrano, M. et al.. Maintenance of broccoli quality and functional properties during cold storage as affected by modified atmosphere packaging. Postharvest Biol. Tech-... 

Kopas-Lane, L.M. and Warthesen, J.J., Carotenoid photostability in raw spinach and carrots during cold storage, J. Food ScL, 60, 773, 1995. 

Kujala, T.S. et al., Phenolics and betacyanins in red beetroot (Beta vulgaris) root distribution and effect of cold storage on the content of total phenolics and three individual compounds, J. Agric. Food Chem., 48, 5338, 2000. 

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