The medal-winning rider crossed the line in 34.812, which was reduced to a real time of 34.433 due to her being in the lower of the two classifications.
Canadian Kate O’Brien – a fellow C4 rider, who held the previous global best – finished just over a second slower at the Izu Velodrome.
Kadeena also retained her title in the time trial, after winning gold in cycling and athletics at Rio 2016.
She also became the first Black athlete in history to secure a gold medal for Great Britain in cycling across disabled and non-disabled athletes.
Speaking to Channel 4 following her medal ceremony, Kadeena said: “I tried not to cry on the podium, I tried to enjoy this moment. I did enjoy Rio but was trying to go well that I didn’t really, it’s a bit overwhelming.
“I got a lot of messages from my family before. My grandad has been in and out of hospital, and this one is for him. I just love him.”
Asked if she had a message for anyone watching at home, Kadeena added: “Do everything you want to do. If you don’t see someone, you don’t think you can be it. People can see me and go on and do better than me.”
Earlier, former soldier Jaco Van Gass broke his second world record in as many days but had to settle for third place in the men’s C1-3 1000m time trial.
The Afghanistan veteran, who powered to 3000m individual pursuit gold on Thursday, finished in 1:05.569.