Hi, I will guide you with few Biotech colleges in India:
1. IIT KGP
2. IIT Roorkee
3. IIT Guwahati
4. NIT
5. PSG college of Technology
For dietician course, you can refer to the below mentioned colleges:
1. Delhi Paramedical & Management Institute, New Delhi
2. Lady Irwin College
3. Institute of Home Economics
4. Amity university

In the post graduation level, Dietetics and nutrition course can be either 2 year Masters programs or 1 year Post Graduate Diploma (Diploma in Dietetics and Public Health Nutrition (DDPHN).
Those with Bachelors degree in food science, home science, hotel management & catering technology, microbiology, biochemistry and medicine are eligible for Post Graduate level Degrees or Diplomas.
Good Luck.