Urban legend has it that Twinkies® can sit on the shelf for 30 years and maintain their eating quality. They have even been entombed in a time capsule as an icon of the 20th century, supposedly in hopes of remaining soft and edible when the capsule is opened. In actuality, “A Twinkie would be considered by most people past its prime in 30 days, with a deterioration of both texture and flavor,” says Troy Boutte, Ph.D., director of innovation, Caravan Ingredients, Lenexa, Kan.

Even so, a 30-day shelf life for a sweet baked product is a pretty remarkable accomplishment. Shelf life extension has improved greatly in the past two years with the introduction extended shelf life (ESL) Ingredients, Boutte says. Caravan’s Cakesoft, which is a combination of enzymes and emulsifiers, can overcome nearly all the shelf life limitations of sweet products.

“The main quality problems that bakers face with regard to extending shelf life of sweet baked goods are staling, mold growth, loss of flavor and resilience, and breakdown of icings, glazes and fillings,” Boutte says. 

Slowing the effects of staling

“Sugar, of course, provides sweetness which is desirable. However, sugar is detrimental in the sense that it dissolves in water and increases the “liquid phase” of the dough or batter,” Boutte adds. “Therefore, as the amount of sugar in a formula goes up, the amount of water is generally decreased to maintain proper dough or batter handling. However, water is the main plasticizer in baked goods and even small decreases of two percent can decrease shelf life by several days. This is mainly a problem in yeast raised doughs.”

For batters, very high sugar levels, such as in high ratio cakes, actually provides a benefit with regard to staling. The high sugar level in these cakes results in much delayed, and more limited starch gelatinization. High sugar level actually increases shelf life, since it is the recrystallization of gelatinized starch that causes staling. This is the primary reason why a cake will generally have longer shelf life than breads.

“Aside from mold growth, by far the primary determinant of shelf life is the amount of starch gelatinized during the baking process and subsequently how much of that starch crystallizes during the shelf life,” continues Boutte “The amount of starch gelatinized is determined primarily by how well the starch is coated with fat or emulsifier, and how much water is available. High fat, low water systems, such as cookies, result in less gelatinization and recrystallization of starch, resulting in less post-bake firming. Emulsifiers complex with the starch, and enzymes break down the starch, resulting in starch that has less tendency to recrystallize.”

Novozymes  Opticake® Fresh slows the retrogradation of starch molecules in wheat flour without causing a gummy, non-elastic or sticky crumb, says Gary Johnson, regional marketing manager, Novozymes North America, Franklinton, N.C.

Synergistic freshkeeping technologies

Using enzyme and emulsifier technologies together work better than any single ingredient by itself. For instance a cake may have a shelf life for two weeks with either an emulsifier or a hydrocolloid, but with a combination of these ingredients with a freshkeeping enzyme, the life may be extended by to as much as three weeks without breaking down, Johnson notes.

“Lallemand offers products for use in chemically leavened baked sweet goods to keep them softer and more resilient using Novozyme’s cake freshkeeping technology with a starch modifying enzyme,” says Jan van Eijk, Ph.D., research director, Lallemand Baking Solutions, Montreal, Canada. "[This ESL system] may be used with other ingredients to increase the shelf life of sweet goods or improve eating quality.”