I have been making marshmallows using either glucose syrup or light corn syrup and both recipe turned out well. This is the recipe using knox gelatin 1 cup cold water, divided 3 1/4-ounce envelopes unflavored gelatin OR 21 grams 2 cups sugar 2/3 cup light corn syrup 1/4 teaspoon salt 2 teaspoons vanilla extract--cooked the syrup to 240 F (fyi: my thermometer is properly calibrated). I beat the mass for 11 minutes. I want to use 42 DE Corn (which is clear and thick like glucose) syrup because it is I believe preservative free and contains no HCFS. I also switched to 250 bloom BEEF gelatin ( I didn't like the funky odor and taste of knox gelatin). I made a batch using light corn syrup and 21 grams beef gelatin and the marshmallow was not as thick and seemed runnier but the texture was still right. I found out later that gelatin from pork sets better than beef. Knox has 225 bloom. I made another batch, used the 42 DE corn syrup and used 30 grams of beef gelatin. The firmness was right but the texture was just not marshmallow. It wasn't fluffy and seemed to melt in my mouth in a bad way. After 12 hours, the texture improved somewhat but I know that it would not turn out the way it used to. I don't know if it is the corn syrup or the beef gelatin. Can pure corn syrup (42 DE) be used interchangeably with glucose syrup or light corn syrup?