Patent GB-901356-A (GB)
Title: Coffee bean products and methods for producing such products
IPC: A23F5/06
Filed: 1958-09-18
Abstract: 901,356. Coffee extracts. BONOTTO, M. Sept. 18, 1958, No. 29907/58. Class 129. Raw coffee beans, after being subjected to a pre-conditioning temperature below roasting temperature until roasting is about to commence, and the heat insolubilizable vegetable matter in the beans has been insolubilized, are particulated to produce a meal from which an aqueous extract is prepared which is then concentrated and subjected to roasting temperature to develop the flavour and aroma. The beans are heated to 200‹ to 212‹ F. in a conventional roaster to drive off moisture and then the temperature is raised to 300 ‹ to 310 ‹ F. and, after a short time at this temperature, heating is continued until a slight odour of roasted coffee can be detected and a slight swelling of the beans after which the beans are discharged and rapidly cooled. The beans are then ground, comminuted or flaked and subjected to aqueous extractions. The percentage of coffee solids in the extract may be increased by a hydrolyzation operation which solubilizes hemi-celluloses and the like in the green coffee beans, e.g. by subjecting the pre-conditioned beans to elevated temperatures and pressures during the aqueous extraction. The extract, which may be filtered if necessary, is concentrated to 50 to 75% solids. If these heat treatments destroy the organic oxidative catalysts in the green beans, these must be replaced before roasting, e.g. at 350 ‹ F. Roasting may take place in an inert gas under pressure or at a lower temperature in the presence of an oxygen-containing gas, e.g. air, oxygen, ozone or mixtures thereof or of oxidants, e.g. hydrogen peroxide, which liberate oxygen. Preferably the extract is concentrated prior to roasting, e.g. to 45 to 90% solids, and preferably 80%. The fluid extract is placed in storage tank 1, Fig. 1, where it may be pretreated if desired and from which it is fed through a proportioning pump 2 to roasting heat-exchangers 3, 4, 5, which successively increase the temperature until the roasting temperature is reached. The extract is discharged from the system through valve 6 to tank 7. Thermometers 11, 11a, 11b indicate the temperature at different points in the system in which the flow is controlled by valves a, b, c, d, e, f, g. Check valves h, h<SP>1</SP> are provided to prevent back flow of extract to devices 9, 9a. The oxidant is stored in a tank 8 which may be used for supplying an inert gas or may be dispensed with. If ozone is to be used as an oxidizing agent, an ozonizer is provided between valve g and tank 8. An oxidizing agent may be introduced into the system at more than on point. In a modification of the process, Fig. 2 (not shown), the extract is heated rapidly to roasting temperature. The roasting apparatus 4a, Fig. 3, comprises a vertical tubular container 20 with an axial shaft 21 mounted in bearings and an inlet 25 at the upper end to which coffee extract is fed and an exit pipe 28 at the lower end. The pressure in the apparatus is controlled by release valve 25a to permit the discharge of excess gas developed during operation. A rotor with blades 29 is mounted on shaft 21 and rotates to throw the extract as a film against the walls of the container which are heated by a jacket 30 supplied with heating medium. Alternatively, roasting may be carried out in apparatus, Fig. 4, comprising a cylinder 34 with a heating jacket 34a and mounted in bearings, a coaxial shaft 35 with an enlarged portion 36 with scrapers 37. The extract is continuously pumped into the annular space through pipe A5 and discharged through pipe B5 duration of the operation being regulated by valve C5. The extract may be spray dried.