UEM Kolkata is ranked 3rd best college in West Bengal and is currently at the 79th Position in NIRF ranking. Heritage Institute of Technology is at the 154th position in the engineering category of the NIRF ranking.

Admission:

UME- The institute offers various courses at UG and PG level, such as BBA, BCA, B.Sc, B.Sc LL.B, BBA LL.B, Bachelor of Hotel Management, MBA, etc. For UEM, the admissions are entrance scores based. It accepts IEM JEE, CAT, MAT, JECA scores for admission to different courses.

Heritage Institute of Technology- The popular courses at Heritage are B.Tech, M.Tech, MCA. For admission, it accepts JEE Mains, PGETand JECA scores.

Placement:

UEM- It has a placement percentage of 123%; almost all the students get 2-3 job offers.

• The average package is nearly 4.2 Lakhs per annum. The highest package offered was 40 Lakhs per annum in 2019 placements.
• Top recruiting companies of the college are- TCS, Wipro, Videonetics, Codeclouds, NRI Fintech, Think analytics, Global Logic, etc.

Heritage Institute of Technology- Heritage has a placement rate of 78%.

• The average package offered is 4 Lakhs per annum. The highest package goes up to 16 Lakhs per annum.
• Top employers’ of the college are TCS, Tech Mahindra, IBM, Cerner Corporation, Ericson, Birla, and DX Core Design.

Both UEM and Heritage are reputed institutes of Kolkata. So, choose which institute will be better for you according to your convenience.

Both colleges are on par with one other in terms of faculty and academics. Both, Haldia Institute of Technology and Heritage Institute of Technology are approved by AICTE and private universities located in West Bengal. But if you are passionate about chemical engineering, aim for IITs.

Both colleges offer Bachelors in Technology in Chemical Engineering. Discussed below are some details about the Chemical Engineering courses offered by these two institutes. 

About 7-8 years ago, all or most of the current faculty of the Heritage Institute of Technology used to be part of the Haldia institute of technology. So there is no big difference in the degrees offered by these two institutes. You only get different degree certificates from HIT and MAKAUT.

Above all, it is suggested to prepare for JEE so that you can choose a better or equivalent institute to IIT. Because college name matters.

Heritage institute of technology is ranked at 154th position in the engineering category by NIRF whereas UEM is ranked at 96th position in the same category by TOI 2020. Heritage offers 9 specializations in B.Tech and UEM has 12. Biotechnology is one of them. Top recruiters at the institutes for the course are the food and beverage industry, laboratories, and pharmaceutical companies.

Admission:

• For the Heritage Institute of Technology,10% of the admissions are done through the JEE counseling process. 80% of the admissions are finalized by the WBJEE counseling process and the remaining 10% seats are reserved for management quota.
• For UEM the admissions for BTech Biotechnology are based on the ranks of IEMJEE. The cut-offs are declared at the time of admissions.

Placements:

UEM- In UEM almost all the students get 2-3 job offers.

• The average package is nearly 4.2 Lakhs per annum. The highest package offered was 40 Lakhs per annum in 2019 placements.
• Top recruiting companies of the college are- top pharmaceutical companies, laboratories, Pepsico, TCS, Wipro, Videonetics, Codeclouds, NRI Fintech, Think analytics, Global Logic, etc.

Heritage Institute of Technology- It has a placement rate of 78%.

• The average package offered is 4 Lakhs per annum. The highest package goes up to 16 Lakhs per annum.
• Top employers’ of the college are- Kissan, Cerner Corporation, Ericson, and DX Core Design.

Both UEM and Heritage Institute of Technology are reputed colleges in Kolkata and offer decent academics and placement opportunities for BTech in Biotechnology. As for which institute is better, you should be the one to decide that.

The Placements cell coordinates with various industries and organizations for placements and internships of students. High numbers of students placed in companies like TCS (Tata consultancy services) and Infosys. These companies are mass recruiters for Heritage institute of technology. Placements statics of Heritage institute of technology are:

• TCS, Wipro, star cements and Omics international are major recruiters, 371 out of 450 students placed in these companies in the year 2018.
• Other recruiters are BYJU’s learning app, Extra Mark Education India Pvt. Ltd, Young optics, Tega industries, skipper limited and Careers Coms HR services.
• Highest package offered in the institute is 16 Lakhs per annum by Microsoft in the year 2014.
• Students have been placed in 55 plus companies in campus interviews.
• Average placement of the HIT is between 3 to 4 lakhs per annum every year.
• More than 70% of students placed in TCS in mass recruitment every year.
• Maximum of students placed every year, so HIT have nearly 100% placements.

Except for placements, students of HIT also take part in summer internships and mock interviews sessions for each branch. The institute also signed a MOU with New Jersey institute of technology (NJIT) for students exchange program. There is also one ED–cell (Entrepreneurship development cell) in the institute for providing a platform to young entrepreneurs. So if the academics report is at least 6.75 one will get placed in companies.

Being one of the oldest engineering colleges in India, IIEST Shibpur is known for its legendary status, well-equipped campus, and a thorough specialization across more than 48 courses. HITK on the other hand is a private autonomous college with a Grade B++ NAAC Accreditation, approved by AICTE, and offers 25 programs across 2 streams.

We can compare the two institutions based on the following factors:

• Ranking: IIEST Shibpur is ranked at 19 by NIRF under engineering institutes in India whereas HITK Kolkata has been ranked at the 150^th position by NIRF under the same category.
• Courses: IIEST Shibpur offers 48 courses in 5 streams with 29 specializations and also offers programs in Management, Architecture, Science, IT, and software. HITK offers a total of 15 courses in Information Technology and Engineering across BTech, MTech, and MCA degree programs with about 8 specializations for undergraduate BTech degree students.
• Infrastructure: The campus at IIEST Shibpur is well structured with classrooms, laboratories, research labs, a library, high-speed internet across the campus, a sports complex, and 17 hostel buildings. HITK has a top infrastructure with fully air-conditioned classrooms, a 20,000 square feet library, sports complex, hostels, and an auditorium.
• Placement Services: In terms of placements, IIEST observes nearly 90+ companies and offers an average median salary of 6.5 LPA with the highest salary package being 39.12 LPA. It sees top companies like Microsoft, Amazon, Deloitte, and more for recruitments. HITK offers an average median salary of 3.4 LPA and does not see many core companies for recruitments. Some of the top companies for placements are TCS, Apollo Paints, HDFC Bank, and IBM.

Based on ranking, campus and placement services students who are looking to join an undergraduate or graduate degree program in Engineering can make their choice accordingly. Both the colleges offer detailed course modules but if your JEE scores are good, it will be comparatively better to opt for IIEST Shibpur.

As I know some people from these institutes you mentioned above, it will be clearer to base their ideas upon the rankings on different factors. 

In terms of Academic Credentials and Research works:

• Kalyani Government Engineering College will be my first choice. It is a Government-run College bestowed with some great Professors.
• Heritage Institute of Technology will be 2nd, as it also has some of the most influential professors. It is an autonomous institute. 
• This will be followed by Jalpaiguri Government Engineering College.
• Finally, the Institute of Engineering and Management, as there have been reports of faculty shortage.

In terms of Social life and Co-curricular Activities:

• Heritage Institute of Technology tops this criteria. 
• Whereas, Kalyani Government Engineering College is in the 2nd position.
• Followed by Jalpaiguri Government Engineering College and IEM.

In terms of Locational merits and Infrastructure,

• Heritage has one of the best infrastructures and is apparently only 10 mins from the major junction of Ruby Hospital or Desun Square.
• IEM also has established both the criteria really well, yet it somehow gets difficult for South Kolkata students.
• They are followed by Kalyani Government Engineering College and Jalpaiguri Government Engineering College.

In terms of Placement Scenario,

• Institute of Engineering and Management and Heritage Institute of Technology are the same in terms of their placement drives.
• Followed by Kalyani Government Engineering College and Jalpaiguri Government Engineering College

In terms of Affordability: (Fees, Accommodation, Miscellaneous Expenses)

• Kalyani Government Engineering College
• Jalpaiguri Government Engineering College
• Institute of Engineering and Management and finally,
• Heritage Institute of Technology

Hope this layer to layer breakdown has helped you gain some insight about the question you asked. 

It's amazing that you're a HITK student, my brother was one too and his friend and his colleague's daughter as well. Coming back to your question, yes, you can change your stream in the first year. 

Build a CGPA of 8.5 or above to apply. You will become eligible for application. You can then easily apply for a change of stream. 

You may get disappointed when the administration tells you that the seat will be allotted on the basis of availability. The higher your score, the greater are the chances- they will hint at this as well, but don't lose hope because they will have a seat for you.