Kolkata, August 11 (IANS) Coconut water can be kept fresh for months without preservatives, thanks to a new technique developed by scientists at the Indian Institute of Technology, Kharagpur. Untreated coconut water has a shelf life of only 24 hours. The team of Sankha Karmakar and professor Sirshendu De, Department of Chemical Engineering, IIT Kharagpur, used a membrane-based separation process through which all the bacterial content can be removed. Shelf life is enhanced to around 18 weeks without any use of preservatives. "Generally, all the bacterial content can be removed by a microfiltration membrane or any ultrafiltration membrane. The membrane was such selected that it eliminates the potent sites for microbial growth (enzyme polyphenol oxidase and high molecular weight proteins present in the coconut water) to its best extent, so that further bacterial growth can be arrested," the researchers said in a statement on Friday. It can be stored in aseptic packaging for 18 weeks under normal refrigeration, they claim. The sterilised coconut water was tasted and scored by three professors from chemical engineering department, 10 Ph.D scholars and two children, in terms of aroma, taste, odour, texture, colour and acceptability. "It was found that the treated coconut water maintained all its nutritional properties even after weeks of storage study. The process is better than conventional sterilization process like, hot pasteurization or freezing because of its economical viability, easy scalability and high storage tendency without any additional additive or preservative," the researchers added.