Potato processing freezing process

Most NMR studies of potato have focused on understanding the effects of processes such as boiling, frying, freezing and drying. Exceptions are the NMR microimaging of healthy and diseased potato tubers reported by Goodman and co-workers, and relaxometry responses in healthy tubers... 

Figure 3.9 Influence of product thickness and heat transfer coefficient on mean freezing rate for potato slices. From Rios, G.M., Marin, M. and Gibert, H., New developments of fluidization in the IQF food area, in McKenna, B.M., (ed.). Engineering and food, volume 2, processing applications, International Congress on Engineering and Food, 1983, Elsevier, 1984, figure 3. With kind permission of Springer Science and Business Media.

The cited observations suggest that it is possible to identify potato cultivars with low or high phenolic acid content for human use and to select processing conditions that minimize losses of phenolic compounds. In summary, the methods we developed and used to determine the content and distribution of phenolic compounds in potato plant flowers, leaves, and tubers, in the peel and flesh parts of potato tubers, and in freeze-dried and processed commercial potatoes merit application in numerous studies designed to assess the role of potato phenolic compounds in host-plant resistance, plant breeding, plant molecular biology, food chemistry, nutrition, and medicine. The described wide distribution of phenolic compounds in different commercial... 

Looking back also over the historical development of quality requirements for processed foods, freezing when properly carried out is undoubtedly the most satisfactory method for the longterm preservation of vegetable produce. The low temperatures commonly prescribed for frozen foods (—18°C) can maintain initial quality and nutritional value practically unchanged, so that frozen and fresh vegetable products differ only in texture (Canet, 1989), which is however a particularly important quality attribute in potato products. 

Alvarez, M. D., Morillo, M. J., Canet, W. (1999). Optimisation of freezing process with pressure steaming of potato tissues c Monalisa). J. Sci FoodAgric., 79,1237-1248. 

Canet, W., Espinosa, J. (1984). The effect of blanching and freezing rate on the texture of potatoes, carrots and peas, measured by mechanical tests. In P. Zeuthen, J. C. Cheftel, C. Eriksson, M. Jul, H. Leniger, P. Linko, G. Varela (Eds.), Thermal Processing and Quality of Foods (pp. 678-683). Elsevier Applied Science, London. 

A Turkish study examined the effect of freeze-storing peeled, blanched then fried potatoes and found a 10% loss of vitamin C after 6 months of storage at — 18°C (Tosun and Yiicecan, 2008). However, a 51% loss was caused by the pre-freezing operations, which sounds a cautionary note about the importance of how potatoes are handled during processing. Some of our own... 

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