Many people probably know marshmallows from toasting them over a campfire. Kraft Food’s JET-PUFFED marshmallows are widely available, and involve some interesting technology, so I will try and explain the basic procedures involved in making these soft and airy products. But, I have to admit that I do not know the exact recipe used for them.
The main ingredients for this product listed in order are corn syrup, sugar, modified corn starch, water and gelatin. The first step is to hydrate and dissolve the gelatin in hot water. Then, the corn syrup, sugar, modified corn starch and the rest of the water are combined and concentrated by evaporation of water until the boiling point rises to somewhere around 240° to 245°F.
Next, the hot syrup and gelatin solution are combined and the marshmallow becomes a marshmallow when air is incorporated into the still hot molten mixture.
According to the company’s web site – Kraftfoods.com – jet puffing is a patented process used since 1953 to incorporate air into these particular marshmallows [Note: there is more on the history of marshmallows on that site as well, including the fact that over 90 million pounds of marshmallows are purchased in the US annually!]. The marshmallow mixture is then shaped via a process called extrusion. According to the Kraftfoods.com web site, this involves pumping the mixture through tubular shaped pipes. The temperature of extrusion has to be just right so that the mixture will flow under pressure, but hold its shape after leaving the pipe. After further cooling, the marshmallow structure sets and they are cut into individual cylindrical pieces, dusted with corn starch to prevent sticking and bagged for sale.
We see the return to the molten state when we toast the marshmallows over the open fire because the gelatin gel part of the marshmallow melts back into the liquid state. Thus, gelatin-water gels in general are said to be “thermoreversible”. These same ingredients are used to make rubbery gummy bear type products (minus the starch), chewy spice drops (minus the gelatin) or jelly candies (replace the starch and gelatin with pectin). It is magical how these different biopolymer gelling agents interact with the corn syrup and sugar to give so many variations of texture.
Ph.D. Cornell University
Food Polymer Science
Daughter (Allison) and son (Scott)
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Higher Ed. Administrator, currently the director of the Big Red Barn Graduate and Professional Student Center at Cornell