The 29-year-old beat fellow finalists Andrew Kojima and Tom Rennolds to become only the second female winner in eight years.
On her win, Permalloo said: "I am completely and utterly overwhelmed. I never thought it was going to be me that would win, the guys [Tom and Andrew] were so amazing and I just never thought it could happen to me.
"I am so happy and pleased that I was able to win by staying true to my roots. I am proud to have made my family proud and to support Mauritians as well. I think if my dad was around he would have been the proudest person ever."
Judge John Torode said: "What Shelina has done throughout this competition is outstanding. She is a very special cook with an exceptional talent who always wears a smile and cooks with care, to assault the senses and bring sunshine to a plate."
Gregg Wallace added: "If ever there was a restaurant that had to happen it is Shelina's because her food is incredible. You can't find it in very many places; you can't really find it outside of Mauritius. I agree, she really does put sunshine on a plate."
The final task saw contestants prepare a three-course meal for judges Torode and Wallace.
Permalloo will next appear at the BBC Good Food Show at the Glow, Bluewater from April 12-15.
Of the live show, she added: "I'm really excited and equally nervous to be cooking live alongside some incredible chefs like Tim Anderson and Lisa Faulkner at the launch of BBC Good Food at Glow, Bluewater. It will be incredible to be in the same space as these guys!"
Talking about her toughest moment during the series, she said: "I think every challenge was tough but the best thing was how much you learn at the end of it. Thailand was probably the most physically exhausting because of the heat and the sheer amount of arm power needed to pound those pastes!
"Cooking for royalty in Thailand was an incredible experience, I doubt I'll ever have the honour of cooking for royalty again, seriously a once in a lifetime opportunity."
On her future career, she added: "I dream of opening a restaurant one day, raising the profile of Mauritian food in the UK, and be working with, and surrounded by, food."
Tim Anderson became the youngest ever amateur winner of MasterChef last year.