Effect of Pre-drying Treatments on Quality Characteristics of Dehydrated Tomato Slices

Tomato powder has good potential as substitute of tomato paste and other tomato products. In order to protect physicochemical properties and nutritional quality of tomato during dehydration process, investigation was carried out using different drying methods and pretreatments. Solar drier and continuous conveyor (tunnel) drier were used for dehydration where as calcium chloride (CaCl2), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl2 +KMS), and sodium chloride (NaCl) selected for treatment.. lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning in addition to moisture, sugar and titrable acidity were studied. Results show that pre-treatment with CaCl2 and NaCl increased water removal and moisture mobility in tomato slices during drying of tomatoes. Where CaCl2 used along with KMS the NEB was recorded the least compared to other treatments and the best results were obtained while using the two chemicals in combination form. Storage studies in LDPE polymeric and metalized polyesters films showed less changes in the products packed in metallized polyester pouches and even after 6 months lycopene content did not decrease more than 20% as compared to the control sample and provide extension of shelf life in acceptable condition for 6 months. In most of the quality characteristics tunnel drier samples presented better values in comparison to solar drier.





References:
[1] S. Rangana,. "Handbook of analysis and quality control for fruit and
vegetable products". Tata McGraw-Hill Publishing Co. Ltd, ED-6, pp. 300-380, Jan. 2000.
[2] M. Dubois, K.A. Gilles, J.K. Hamilton, P.A. Rebers, and F. Smith,
"A mehtode for carbohydrate stimation," Anal. Chem., vol. 28, pp. 350-353, 1956.
[3] D.J. Hart, and K.J. Scott, "Development and evaluation of an HPLC
method for the analysis of carotenoids in Foods, and the measurement of
the carotenoids content of vegetables and fruits commonly consumed in
the UK," Food Chem., vol. 54, pp. 101-111, 1995.
[4] A. A. El- Sebii, S. Abdoul-Enein, M. R.I. Ramadan, & H.G. El-
Gohary, "Experimental investigation of an indivect type natural convection solar dryer," Energy Conversion and Management, vol. 43,
pp. 225-226, 2002.
[5] W. W. M. McMinn, and T. R. A. Magee, "Physical characteristics of
dehydrated potatoes," J. Food Eng., vol. 33, pp. 49-55, 1997.
[6] D. G. Prabhanjan, H. S. Ramaswamay, and G. S. V. Raghavan,
"Microware assisted air drying of thin layer carrots," J. Food Eng., vol.
25, pp. 283-293, 1995.
[7] K. Gierschner, W. John, and S. Philippos, "Specific modification of
cell wall hydrocolloids in a new technique for processing high quality
canned vegetables," Deutsche Lebensmitel-Rund Schan, vol. 91,
pp.103-109, 1995.
[8] O. A. Olorunda, O. C. Aworh, and C. N. Onuha, "Upgrading quality
of dried tomato: Effect of drying methods, conditions and pre-drying
treatments," J. Sci. Food Agric., vol. 52, pp. 447-454, 1990.
[9] R. G. Gupta, and N. Nath, "Drying of tomatoes," J. Food Sci. Tech.,
vol. 21, pp. 372 - 376, 1984.
[10] M. Y. Gallali, Y. S. Abujnab, and D. F. Bannari, "Preservation of
fruits and vegetables using solar drier: a comparative study of natural
and solar drying, III; chemical analysis and sensory evaluation data of
the dried samples," Renewable Energy, vol. 19, pp. 203-212, 2000.
[11] S. O. Okanlawon, M. H. IbraHIM, and A. O. Oyebani, "Effect of
pre drying treatment on the storage of dried tomato," Tropical Sci., vol.
42, pp. 40-41, 2002.
[12] S. K. Sharma, and M. L. Maguer, "Kinetics of Lycopene
degradation in tomato pulp solid under different processing and storage
condition," Food Res. Intl., vol. 29, pp. 309-315, 1996.
[13] A. K. Baloch, K. A. Buckle, and R. A. Edwards, "Effect of sulphur
dioxide and blanching on stability of carotenoids of dehydrated carrot,"
J. Sci. Food Agric., vol.40, pp. 179-187, 1987.
[14] S. Poretta, and L. Sandei, "Effect of chemical composition on nonenzymic
browning in tomato products," Industrie Alimentari, vol. 29,
pp. 113-116, 1990.
[15] M. Simon, J. R. Wagner, V. G. Silveira, and C. E. Hendel,
"Calcium chloride as Non-Enzymatic Browning Retardant for
Dehydrated White potatoes," Food Tech., vol. 12, pp. 271-275, 1955.
[16] W. A. Baloch, S. Khan, and A. K. Baloch, "Influence of chemical
additives on the stability of dried tomato powder," Intl. J. Food Sci. Tech., vol. 32, pp. 117-120, 1997.
[17] G. A. Picchioni, "Membrane lipid metabolism, cell permeability
and ultra structural changes in lightly processed carrot," J. Food Sci.,
vol. 59, pp. 601-605, 1994.
[18] J. C. Rosen, and A. A. Kader, "Post harvest physiology and quality
maintenance of sliced pear and strawberry fruits," J. Food Sci., vol. 54,
pp. 656 - 659, 1989.
[19] H. Izumi, and A. E. Watada, "Calcium treatments affect storage
quality of shredded carrot," J. Food Sci., vol. 59, pp. 106 - 109, 1994.
[20] G. M. Glenn, and B. W. Poovaiah, "Calcium- mediated post
harvest changes in texture and cell wall structure and composition in
Golden Delicious apples," J. Am. Soc. Hort. Sci., vol. 115, pp. 962 -
968, 1990.
[21] E. M. Ahmed, S. Mirza, and A. G. Arreola, "Ultra structural and
textural changes in processed carrot tissue," J. Food Quality, vol. 57,
pp. 56-60, 1991.
[22] M. K. Krokida, and D. Marinos-Kouris, "Rehydration kinetics of
dehydrated products," J. Food Eng., vol. 57, pp. 1-7, 2003.
[23] M. R. Okos, G. Narishman, R. K. Singh, and A. C. Weitnauer,
"Food dehydration In: Handbook of Food Engineering," Marcel Dekker,
pp. 437-562, 1992.
[24] P. P. Lewicki, H. V. Le, and W. P. Lazuka, "Effect of pretreatment
on convective drying of tomatoes," J. Food Eng., vol. 54, pp. 141-146,2002.
[25] S. Suguna, M. Usha, V. V. Screenarayanan, R. Raghupathy, L.
Gotthandapani, "Dehydration of mushroom by sundrying, thin layer
drying, fluidized bed drying and solar cabinet drying," J. Food Sci. Tech., vol. 32, pp. 384-388, 1995.
[26] J. Shi, M. Maguer, Y. Kadkuda, and A. Liptay, "Lycopene degradation and isomeration in tomato dehydration," Food Res. Intl., vol. 32, pp. 15-21, 1999.
[27] V. R. Sagar, D. S. Khurdiya, and K. A. Balakrishnan, "Quality of
dehydrated ripe mango slices as affected by packaging material and
mode of packaging," J. Food Sci. Tech., vol. 36, pp. 67-70, 1999.
[28] K. K. Adom, "Combined effect of drying time and slice thickness
on the solar drying of okra," J. Sci. Food Agric., vol. 73, pp. 315-320,1997.