About 30% of the 1,141 products in the enlarged range were new while 40% had been revamped, said commercial director Mike Coupe.
Speaking exclusively to The Grocer, he said: "We took the decision about 15 months ago to revamp the range, and the nature of these things is that you get a bigger bang for your buck if you do it all at once. We think it's probably the biggest launch ever because we're launching 1,141 products in about two weeks."
Work on the range, in which Sainsbury's had invested "millions", had involved creating new lines, improving existing ones, revamping packs so more of the product was on view, and reworking the logo.
"Above all, taste is the heart of what we are trying to do with the brand," Coupe added. "So when we say they're taste-tested by customers, they're not taste-tested by customers at random in a hall, they are statistically taste-tested and benchmarked against other competitive products."
Three-quarters of Sainsbury's shoppers currently buy Taste the Difference, but Coupe said the relaunch had also focused on attracting younger shoppers. A new sub-brand called Bistro promises restaurant-quality fare such as lamb shanks with red wine jus, and pork belly with vintage cider.
A TV advertising campaign for the relaunched range, starring Jamie Oliver, kicked off on Wednesday this week.