According to Official Guinness Records,
The most people tossing pancakes is 890 and was achieved at an event organised by the University of Sheffield (UK), in Sheffield, UK, on 15 February, 2012.
Although over 1,500 signed up for the event online a total of 930 participants attended, unfortunately 40 participants had to be discounted due to either dropping their pancake or not managing to toss their pancake within the allotted time.
For a complete list of 2012 records, please visit 2012 Guinness Records in United Kingdom.