Dehydration was the main process once upon a time to preserve many food materials, especially fruits, vegetables and nuts. Sun drying was the cheapest mode while large dehydration plants also were working for commercial drying purposes. Sun dried fruits made in different countries which include raisins, dates, plums, apricots etc are marketed world wide attracting very high prices. Sun drying is also the frequently used process for preparing dry fish in coastal areas. However dehydration as a food processing technology lost its utilitarian value after the advent of more efficient technologies like canning, refrigeration, freezing, aseptic packing, irradiation, etc and it is more or less confined to tropical and temperate fruits only. Freeze drying where drying takes place at sub-zero temperatures is supposed to give a finished product with superior quality and some foods are processed to a limited extent using this process. High capital investment, high cost of processing and subtle changes in texture during the drying process make this technology less preferred by the industry. Against such a background comes the news about the development of a drying technology by an IIT trained entrepreneur at Mumbai which is claimed to give superior quality finished products and it is interesting to read the news to have a hang of it.
"More than 3,000 mothers like Prithi, from across Mumbai, come to Meisheri to send food to loved ones abroad. What sets Meisheri's service apart from other "heat and serve" products is that the food retains its nutritional value, flavour and taste and there are no preservatives added. The service is so customised that Meisheri often has mothers show him exactly how much their sons and daughters eat at each meal so that he can tailor the food packets accordingly and avoid wastage. The idea was seeded when a friend complained to Meisheri about how her daughter had lost six kilos after going to study in the US. "I thought that it was important for our children to be well-fed when they are studying," he explains. And so the first "meal pack" was born. He has since dehydrated all kinds of dishes: from khichdi, biriyani (and its raita accompaniment), gajar ka halwa to idli and rajma. His busiest month is August, just before the students depart for their fall academic semester".
Though the entrepreneur has not revealed the secret of the process, it is known to be based on slow drying with a cold air which ensures that the product is not exposed to drastic temperatures which can destroy the texture and some of the thermally unstable nutrients. Though this entrepreneur has been hawking this technology for the last two decades, there doe not appear to be any industrial plant working any where using the same. The fact that he has been catering to families around Mumbai tells its own story viz the plant design is limited to a few kilogram processing capacity. Some years ago this process was considered highly suitable for drying of many herbs which contain heat labile active constituents but why this has not taken of in a big way, considering its advantages, is not clear. The credibility and viability of any new technology can be proved only when it is used for manufacturing commercial volumes and products marketed successfully.