maltodextrin is mostly non-fermentable and not sweet so it's pretty useless for priming. that's why you see it mentioned being added for mouthfeel, the long chain sugars create body with out adding sweetness. you can use corn syrup but 3/4c syrup doesn't have the same sugar content as 3/4 cup dry. try searching for "corn syrup" + priming, maybe someone figured out the ratio. another thing you can do is make invert sugar from your household white cane sugar. add your 3/4c sugar to 2c water and add about a tablespoon of lemon juice (or citric acid if you have it, at 1g/kg of sugar). mix these in a pot on the stove on med heat and allow to boil softly for 20-30 minutes. you've just turned pretty fermentable sucrose into REALLY fermentable glucose and fructose. check out wikipedia for all the science. this syrup will have the right amount of nearly 100% sugar so you won't get any weird flavors from the sugar. good luck.