GB681242A - Method of and apparatus for the heat treatment of fruit and vegetable foodstuffs - Google Patents

Abstract

681,242. Making jams, jellies, &c. REICH, G. T. Sept. 19, 1947 [Nov. 30, 1939], No. 25526/47. Class 49. In the manufacture of jams, jellies, and the like, fruit or vegetable foodstuff containing natural sugar, or to which sugar is added, is passed in a continuous stream through a heating zone at predetermined temperature without agitation so that the rate of passage of every portion of the mixture through the heating zone is that of the overall rate of passage therethrough, and the volume of mixture is adjusted with respect to the rate of flow to maintain each portion of the mixture in the heating zone for a predetermined constant period. Preserves of citrous peel, strawberries, cherries, peaches and pineapple, and jellies of cranberry and grape juices are referred to. With the apparatus of Figs. 1 and 2, fruit juice and sugar, and, if desired, pectin, and also, if the fruit is insufficiently acid, tartaric or citric acid, are continuously fed from containers 17 and 18 into a dissolver 11 in which its a screw conveyer 12, and the contents of the dissolver are heated by a jacket 14 and by coils 13 in the upper portion, maintenance of the volume of mixture suitably to the rate of feed being by adjustment of the height of an outlet pipe 20. Some or all of the evaporation may be effected in the dissolver, water vapour being withdrawn through an outlet 19. From the outlet 20 the mixture passes, either directly by a pipe 22 or by way of an evaporator 21, through a .heater 24 or a filter press 25, or both, to a tank 26. In the tank 26, which is provided with a heating jacket 27, heating coils 28, and alternating lateral baffles 29, the mixture is subjected to heating below boiling temperature for a time sufficient to bring about the desired degree of inversion of the sugar, the volume of the mixture in the tank being regulated by adjustment of the height of an outlet pipe 30. Scum formed during the heating of the mixture may be removed; with the apparatus of Fig. 5, a tank 50 is provided with a scraper assembly 51 eccentrically mounted so that members 53 lift scum and move it to scraper members 55 on a rotating wheel 54, which members transfer the scum through a funnel 57 to a centrifugal separator 58, wherefrom the liquid portion is returned at 59 and the scum portion discharged at 60.