In Minneapolis specifically, the city's Star Tribune looked into this in 2014, comparing published statistics from the City of Minneapolis with the 2010 Census to produce the comparison below. In particular:
The department’s diversity problem falls unevenly across its ranks:
while black and Hispanic officers number too few, American Indians and
Asians are represented on the force in percentages that mirror the
city’s population.
Of the 807 officers and cadets in field training currently on the
force, 78.9 percent are white, 9.2 percent are black, 5.2 percent are
Asian, 4.1 percent are Hispanic and 2.5 percent are American Indian.
Women made up 15 percent of the police force in 2013, down from 16.4
percent in 2003.
Part of the reason for this disparity is blamed on the rush to hire new officers leading to less of a focus on ensuring a police department reflective of the community which it serves:
The City Council has authorized the department to hire enough officers
to raise the department to 860 officers; it’s currently near 770
officers on the street, one of the lowest numbers in 25 years.
The city has 1.9 officers per 1,000 residents, a ratio that puts it
below St. Paul and many other Midwestern cities. The depleted force
has seen response times rise while officers have reported stopping
fewer suspicious vehicles and suspicious persons. Violent crime,
meanwhile, has risen 4.7 percent so far this year.
A hiring push will have up to 100 join the force before the end of the
year, Harteau has pledged, though many of the officers will still be
in field training through the end of the year. Some of the hires are
fresh out of the police academy, while others have experience in
departments elsewhere and won’t require as much field training.
Of all 85 of those potential hires — the cadets, recruits and hires
with law enforcement experience — at least 60, about 71 percent, are
white, according to the city figures. The number of white officers
could be higher because some of the remaining 25 candidates didn’t
share their race when they applied, according to the City Attorney’s
office.
Unfortunately, the websites of the City of Minneapolis and of the Minneapolis Police Department appear to have blocked European IPs - otherwise, I would be able to try and find more recent statistics.

More generally throughout the US, the Washington Post has covered this in the wake of the BLM protests, finding that particularly in urban areas, police forces are "consistently much whiter than the people they serve".
As police engage with protesters in cities across the United States,
many major police forces are still much whiter than the communities
where they work. Decades of reform have made police less white, but it
has not been enough to keep pace with the changing demographics of the
country.
This widening racial gap has left very few police forces that resemble
the people they serve, which experts say can hinder community
relations and affect crime rates.

They do, however, note that in the case of Minneapolis:
Hennepin County, which includes Minneapolis, has a police force that
closely matches the community, with a large share of both the
population and police being white.
However, this includes the entire county, not just the Minneapolis police department specifically, which may explain the disparity.