hi,

see you are eligible to write any of the gate paper irrespective of your stream, however you must abide by the eligibility criteria like candidates must be  complete or in final year or 3rd year of bachelors course ,  candidates who are currently in m.sc courses or passed the course are also eligible to apply. however you may self study the gate paper and appear in exam, but at the time of admission to masters course you may face issues for not having the exact qualification. so just research about the m.tech program and the eligibility criteria for admission. here is the gate syllabus link of textile and fibre science which may help you to sort the syllabus.

https://cache.careers360.mobi/media/uploads/froala_editor/files/TF.pdf