Patent GB-935696-A (GB)
Title: A process of drying a water-containing, solid, organic, non-living substance
Inventor: JOHNSON WILLIAM REDMOND
IPC: A21D6/00
Filed: 1959-12-24
Abstract: A water-containing enzyme system is dried by suspending relatively small particles in a liquid medium, other than water in a liquid medium miscible with water, which is not deleterious to the enzyme system and drying by evaporating water from the suspension, while maintaining the suspension at a temperature below that to which the enzyme system is sensitive, by bringing the suspension into intimate contact with a gas while maintaining the enzyme system in suspension. The gas may be passed through the suspension or the suspension may be sprayed into a body of gas.  According to an example, Bacillus subtilis was propagated on a nutrient medium to produce exocellular amylase; the bacterial mat was then separated from the wort by centrifugation.  The wort, containing 7.5% solids, was dispersed in corn oil in a ratio of 0.6 to 1.0 by volume, and the dispersion was heated to 86 DEG F. while air of 14% relative humidity at 75 DEG F. was passed through it for 30 hours.  The dehydration was completed by heating the dispersion to 136 DEG F. and continuing the aeration for 1 1/2 hours. Separation of the oil by centrifugation and solvent extraction yielded a solid having 10.8% moisture with an amylase potency of from 17,000 to 48,000 liquefons per gram.  Specification 582,611 also is referred to.ALSO:A water-containing, organic, non-living substance sensitive to relatively low temperatures such as foods, tea and coffee extracts, enzyme systems and biologicals, and aqueous solutions or suspensions, is dried by suspending relatively small particles of the substance in a liquid medium, other than water in a liquid medium miscible with water, which is not deleterious to the substance and drying by evaporating water from the suspension, while maintaining the suspension at a temperature below that to which the non-living substance is sensitive, by bringing the suspension into intimate contact with a gas not harmful to the non-living substance while maintaining it in suspension.  The gas may be passed through the suspension or the suspension may be sprayed into a body of gas.  Substances mentioned are eggs, meat, fish, applies, pears, bananas, apple sauce, orange juice, tea and coffee extracts, hamburger, potatoes, spinach, beet, onions, wheat, flour, cooked wheatena, molasses, honey, corn syrup, Irish moss, enzyme systems, antibiotics, blood, glands and viruses.  Liquid media.-Animal, vegetable and mineral oils (specified), silicone oil, triethyl or tributyl citrate, dibutyl phthalate, liquid propane, glycerine and, for certain purposes, volatile liquids such as octane; thus an aqueous coffee extract may be dehydrated in octane in a closed system wherein the volatilized octane is condensed and returned to the vessel in which dehydration is taking place.  The rate of water transfer to the gas may be increased by employing liquid media possessing some solvent action on water and incorporating in the liquid medium a wetting agent (specified).  Gases specified are air, nitrogen and carbon dioxide.  The required heat of evaporation may be supplied by heating the gas, the suspension or both.  After dehydration, the bulk of the liquid medium may be separated by decantation, filtration or centrifugation and the residual liquid medium extracted with a suitable organic solvent such as ethyl ether or methylene chloride.  According to an example, to 250 g. commercial liquid egg white there was added 125 g. of cane sugar and the mixture was stirred until the sugar was completely dissolved. This solution was added to 3.5 litres of corn oil, the mixture was heated to 104 DEG  F. and dehydrated to 3% moisture content by passing air of 14% relative humidity at 77 DEG  F. through the suspension for 6 hours at the rate of 2.5 cubic feet per minute. After the dehydration was completed, the bulk of oil was removed in a basket type centrifuge; the residual oil was then extracted by ethyl ether, and the ethyl ether evaporated by exposing the product to a temperature of 110-120 DEG  F. in a drying oven for 12 hours.  Other examples are directed to drying (2) a mixture of egg-yolk and sugar, (3) an aqueous extract of Irish moss, (4) diced potatoes, (5) corn syrup, (6) an aqueous extract of roasted coffee, (7) an amylase-containing wort produced by propagation of Bacillus subtilis and (8) bakers' white flour. Specification 582,611 also is referred to.