Some Quality Aspects of Persimmon Jam Manufactured by Osmotic Dehydration without Thermal Treatment

The traditional way of preparing persimmon jam produces astringent flavours due to the conversion of insoluble tannins into soluble tannins as a consequence of the high temperatures used in the process. For this reason, a new method for preparing this kind of product based on osmotic dehydration was tested, in order to obtain persimmon jam without thermal treatment. In this work, 'Rojo Brillante' persimmon slices were dehydrated to approximately 30 Brix in concentrated grape juice of 65.8 Brix at 30C, according to a previous kinetic study. Then, samples were mixed with concentrated grape juice, potassium sorbate, pectin and citric acid in order to reach a concentration of soluble solids of approximately 48 Brix. Samples were stored at room temperature, and at 4C. Determinations of Brix, humidity, astringency, water activity and analysis of optical and mechanical properties (consistency and extrusion) were performed after 1, 5, 7, 12 and 18 days of storage. Non-refrigerated jam spoiled after five days of storage, but the characteristics of the refrigerated samples barely changed, without the presence of astringency. In conclusion, this method of preparing jam from persimmons could increase the commercial possibilities of this fruit, using refrigerated storage. © 2011 Berkeley Electronic Press. All rights reserved.Corresponding author: M. Igual, marigra@upvnet.upv.es, Food Technology Department, Food Investigation and Innovation Group, Universitat Politecnica de Valencia, Camino de Vera s/n, P. B. 22012, 46022, Valencia, Spain. The authors would like to thank the R&D&D&I Linguistic Assistance Office, Universitat Politecnica de Valencia (Spain), for granting financial support for the linguistic revision of this paper. The authors also thank the Ministerio de Ciencia y Tecnologia (Spain) for the financial support with the project AGL2008-01745.Igual Ramo, M.; Castelló Gómez, ML.; Ortolá Ortolá, MD.; Andrés Grau, AM. (2011). Some Quality Aspects of Persimmon Jam Manufactured by Osmotic Dehydration without Thermal Treatment. International Journal of Food Engineering. 7(5):1-15. https://doi.org/10.2202/1556-3758.21501157