Online grocery delivery startup Instacart, a symbol of the "on demand" economy, said Tuesday it raised $600 million in capital, at a valuation of $7.6 billion.

The funding round led by D1 Capital will be used to expand in North America, where Instacart has partnerships with some 300 retailers including Kroger, Aldi, Loblaw, Sam's Club, Sprouts, Publix, Albertsons and Walmart Canada.

Instacart has raised more than $1.6 billion to date and has 600 full-time employees across North America, according to a statement.

"The US is nearly a $1 trillion grocery market, and last year we saw almost every major grocer in North America bring their delivery business online in a significant way," said Apoorva Mehta, Instacart founder and chief executive.

"We believe we're in the very early stages of a massive shift in the way people buy groceries and we expect that one in five Americans will be shopping for their groceries online in the next five years."

Dan Sundheim, founder of D1 Capital Partners, said in the statement that "grocery is the largest category within US retail and it is also one of the least penetrated online. The industry is at a tipping point and there will likely be a significant acceleration in the adoption of online ordering for grocery delivery over the next few years."