Foods expire, some sooner than others. When it comes to baked goods gone bad, there are basically three modes of deterioration: staling/moisture migration, microbial growth and fat oxidation. Slowing these processes increases longevity and assists with reducing consumer disappointment and product waste.
“In the baking industry, most product development decisions revolve around satisfying consumers and making their eating experience as enjoyable as possible,” said Catherine Barry, director of marketing, National Honey Board. “That can’t happen if you reach into a loaf of bread and pull out a moldy or stale slice.”
Expiration dates are on packages to ensure a positive eating experience, yet some consumers expect a product to have additional days of shelf life at home. That’s why shelf life extenders are often included in commercially produced baked goods that must travel through lengthy distribution channels. There’s a plethora of traditional and clean-label options to address product deterioration to ensure consumers have a positive experience.
“Shelf life extenders have evolved with consumer preferences,” Ms. Barry said. “Back when white bread still dominated the bread aisle, most consumers didn’t read labels, so bakers could use any ingredient to attain a longer shelf life. Today, consumers pay close attention to the ingredients in the products they purchase and are doing everything they can to avoid artificial ingredients, especially preservatives.”
While freshness and taste are top priorities, bakers must maintain cost and labor efficiencies. This includes stocked shelves with fewer expired returns. Sometimes a simple ingredient addition or change in temperature during distribution can extend or reduce shelf life. Kathy Sargent, market director of the bakery division for Corbion, said every day on the shelf is precious when it comes to baked goods.
“Branded breads, buns and rolls need to taste the same in New York City as they do in Los Angeles,” Ms. Sargent said. “Consistency is a way to ensure quality products and brand protection.”
It’s important to understand the various modes of product deterioration to make smart formulation, production and distribution choices.
There is no one-size-fits-all shelf life extension ingredient solution, according to David Guilfoyle, innovation manager-bakery, fats and oils, DuPont Nutrition & Health. “From a staling point of view, the higher the moisture in a finished product, the more stable it is for eating quality,” he said. “From a microbial spoilage viewpoint, however, the higher the moisture is in a finished bakery product, the higher the incidence of microbial spoilage. So, it is a double-edged sword.”
Staling, moisture migration
Although enzymes have been used for well over a decade, their application is still the newest approach to shelf life extension. Products that benefit the most are those that require fresh-keeping and, in particular, those with specific volume requirements, namely bread. Most traditional pan breads are expected to be soft and light in texture and are now also expected to have shelf lives of up to three weeks.
Specific amylases, such as maltotetrahydrolases, are mainly responsible for the anti-staling effects although phospholipase enzymes and bacterial xylanases can provide additional softness. The amylases help products retain original production freshness by modifying primarily the amylopectin portion of the wheat starch, which greatly reduces recrystallization, or retrogradation, over time, resulting in a softer product.
“We work side-by-side with our customers to provide a variety of solutions that use a synergistic enzyme blend to extend the freshness, taste and flavor of baked goods throughout the life cycle, whether it’s a couple of days for foodservice operators or 30-plus days for our customers that push for distribution efficiencies,” Ms. Sargent said.
“In recent years, there have been innovations around enzymes to help protect bakery products throughout their freshness cycle,” Ms. Sargent said. “At Corbion, we have a shelf-life extender that not only enhances freshness but also reduces the amount of sugar, high fructose corn syrup and yeast in formulations.”
The company’s new enzyme solution helps keep sweet goods — large and small cakes, muffins, donuts and more — fresher longer. Bakers may add it at the bowl or optimize the formula to reduce undesirable ingredients and save money.
“It provides higher quality through freeze-thaw cycles, too,” Ms. Sargent said. “By using the new enzyme solution in sweet goods, bakers will benefit with savings from reduced wastes and stales, fuller shelves for enhanced selling opportunities, improvement in the quality of baked goods and the flexibility to meet varying consumer preferences.”
Dry crumb, also known as staling, results from the retrogradation of starch in baked goods. Starch molecules take up water and swell during baking, losing their crystalline structure. Over time, the starch molecules shrink back and recrystallize, or retrograde, compressing and releasing moisture. That loss of moisture causes soft crumb to turn dry and hard. Temperature abuses during distribution and storage can accelerate the staling process.
High consumer interest in gluten-free baked goods and those made with alternate flours complicates matters. “Retaining moisture is a big concern when analyzing the shelf life of various baked goods. With the growing variety of flours on the market, it’s also becoming a lot more challenging,” said Kate Leahy, spokesperson for Sunsweet Ingredients. “Gluten-free baked goods tend to dry out a lot faster than conventional products. Plus, each alternative flour hydrates and dries out differently, making monitoring the shelf life of these products more complicated.”
A number of ingredients can assist with moisture retention. For example, gums do not undergo the retrogradation process. They can slow the staling process by holding onto moisture. Additionally, gums may be able to absorb the excess moisture released by starches to maintain moistness and extend shelf life.
“Ingredion offers several shelf life extension solutions, including starches, both clean label and modified options,” said MacKenzie Sizemore, senior applications technologist, Ingredion. “These ingredients help limit moisture migration or stabilize structures by optimizing viscosity, forming protective films and reducing unwanted texture changes as baked goods age.”
Ingredion’s hydrocolloid, or gum-based, solutions help bind water to provide moistness and a perception of freshness over time, Ms. Sizemore added. Solutions such as sweetener syrups and polyols, or sugar alcohols, provide humectancy or moisture throughout the finished product’s shelf life as well as help control water activity to slow the rate of microbial spoilage.
Ms. Sizemore explained that as important slowing staling is, managing moisture migration must also be addressed. This problem can cause baked goods to become soggy or overly wet or can cause bleeding or running of icings, frostings and fillings.
“Products with inclusions or fillings, or multiple layers or textures that vary in moisture content or water activity across the product components, are prone to experiencing negative texture impacts as moisture migrates from areas of high to low in the food and water activities equalize,” Ms. Sizemore said. “In products such as iced cakes, filled snack cakes, and cookie or cracker sandwiches, this can be a major issue driving loss of shelf life.”
Fruit ingredients are another option to assist with moisture management. For example, the fiber and sorbitol naturally present in dried plum ingredients bind moisture, assisting with tender crumb and slowing staling.
Because they are hygroscopic, prune juice concentrate and dried plum puree help with moisture retention, according to Ms. Leahy. “With prune juice concentrate, a little goes a long way,” she said. It can be used in small quantities for moisture retention in everything from pound cakes and quickbreads to yeast breads and cookies, she added. It can also work well as a binding for bars. The puree can be used at higher concentrations, especially when a chewy quality is desirable, such as in chewy gingersnap cookies.
“In these cases, it can take the place of half of the oil or butter in a formula,” Ms. Leahy said. “A less conventional application is to soak whole grains, such as wheat berries, in a brine of water and a small amount, like 1%, of fresh plum concentrate overnight. The antioxidants in the concentrate help stave off rancidity, allowing the soaked-and-drained grains to be used in whole grain breads with a decreased risk of forming off-flavors.”
Another option to extend shelf life naturally is to add honey.
“This all-natural sweetener not only plays a role in a product’s overall flavor, but it also helps contribute to a moist crumb and delays spoilage,” Ms. Barry said. “Not many ingredients with such a positive perception can naturally accomplish these important functional roles.”
From a functional standpoint, honey’s high acidity (average pH 3.91) inhibits mold growth in baked goods. It also increases the shelf life by maintaining crumb softness. It does this in multiple ways, most notably by functioning as a natural humectant because it has an average water activity of 0.55.
“Liquid honey is hygroscopic and enables products to maintain their moisture content far longer than products that use dry sweeteners,” Ms. Barry said. “By design, honey does not give up its water easily.”
Further, the amylase naturally present in honey promotes crumb softness by effectively hydrolyzing starch, thereby contributing to moisture retention. Honey’s fructose content also holds in a baked good’s moisture.