Popcorn doesn't have enough substance to it, althouth I'm sure you could add some with your regular bait. I guided for a few years when I was younger and found that the meat scraps and donuts, about 5 gallons of each in a 45 gallon drum every 3-4 days works well. Some bears prefer meat, some donuts and some like both. But one thing for sure is that every bear is a little bit different than the other.
Also, take a rake and chew up the ground in front of the barrel where the bear will be standing and pour about 10 gallons of french fryer grease on the ground. When a bear comes in and stands in that stuff, he will leave a scent trail all over hell's half acre that leads right back to your bait for other bears to follow.
I also use to use jello crystals and sprinkle them all around the bait site because they would soak into the ground and leave a nice scent for a few days. I also use to get a spray bottle that could spray about 12 feet and mix up some pancake syrup, raspberry jello and just enought water so that you could spray it and spray it as high up in the trees as I could around the bait site. All these things combined work very well. But it's a lot of work. Anyone who said that baiting bears is easy doesn't have the authority to open there mouth.
Honey burns can work on younger bears that aren't afraid of anything but on large bears, you are only telling the bear when you are at the bait site.
One of my favourite tricks is to always make noise when you're carrying in your bait, not lots of noise, maybe whistle a tune on your way in and way out. The bears are not that far away and can probably hear you coming and leaving. When you walk in with a hunter and you are doing this, the bear hears you leaving and has the green light to proceed.
I did this trick when hunting with my wife and a real nice bear walked into the bait 5 minutes after I left. Her .260 made him lay down with one shot through the heart.
I hope you're successful in your bear hunt. I haven't baited bears in about 4 years now. We have so many bears in Timmins that you just need to drive down a logging road until you see one, get out, load your rifle, take your time aiming while he stands there watching you and shoot him. They have no fear of man anymore. Makes bowhunting start to look appealing because blowing them away with a rifle is starting to get too easy.
Good luck,
Slooshark1