A “ Softer ” Approach to Improving the Quality of Refrigerated Bakery Products FEATURE

F resh bakery products have been a staple food for humans for hundreds of years. Freshly baked products have a flavorful aroma, yeasty, sweet taste, and soft but resilient texture. However, the freshness of bakery products can be lost quickly over time. This loss of freshness is due to a series of slow chemical and physical changes that leads to progressive firming of the crumb, commonly referred to as “staling,” and microbial attack or, more commonly, the appearance of molds (5). The term “staling” refers to the gradually decreasing consumer acceptance of bakery products due to the chemical and physical changes that occur in the crust and crumb during storage, excluding microbial spoilage (2). Consumers no longer consider the product to be “fresh” due to the deterioration of texture, flavor, and aroma (5). The staling process is mainly due to the firming effect caused by moisture transfer from crumb to crust, as well as to the intrinsic firming of the cell wall material, which is associated with starch recrystallization during storage (8). Food scientists and the baking industry have worked for many generations to find solutions that will maintain the freshness of bakery products and extend the shelf life of these goods. Many methods are used to prolong the shelf life of bakery products by delaying microbiological spoilage. Preservatives, such as propionates, are common additives used to minimize microbial growth (5). Modified atmosphere packaging can extend the mold-free shelf life of products, as can various forms of irradiation (5). Controlling storage temperature is an effective way to prevent microbial spoilage for extended periods of time. Frozen and refrigerated storage are also widely used in controlling the spoilage of bakery products. While lowering the storage temperature will reduce microbial growth, these temperatures will also have an impact on the rate of product staling. The temperature at which bread is stored has a direct impact on its staling rate. Higher temperatures retard staling, and cooler temperatures (above freezing) increase it (9). The rate of staling has a negative temperature coefficient (6). Thus, the rate of bread staling is accelerated at refrigerated storage temperatures (7). Product formulation also has a major impact on the characteristics of bakery products. Ingredients used in the formula will impact the product throughout mixing, processing, baking, and storage. Dough strengtheners and conditioners are often used to improve dough processing tolerance, increase product volume, increase softness, and improve grain structure. Removing these additives often results in lower-quality bread. Sugar has many functions in bakery products. American white-bread formulations are relatively high in sweeteners (4). The average formula addition in 1920 was 2% based on flour (4). However, the sugar level increased to as high as 8% in 1958 (4). The high usage of sugar was justified by marked improvements in loaf volume, crust color, flavor, shelf life, and more (11). Aside from the many positive attributes sugars are able to provide, some negative impacts are also observed. Proper dough development requires a greater energy input when large quantities of sugar are present (11). Sweet dough with sugar levels of 20–25% requires as much as 50% longer mix times to maintain loaf volume and produce acceptable eating quality in the finished product (3). With high sugar levels, a perceptible inhibitory effect on yeast activity occurs that depresses the rate of gas production (4). The baking industry is constantly challenged by increasing consumer demands for higher quality and fresher products. The shelf life of bakery products is continually being stretched for both consumer satisfaction and production and marketing efficiency. Consumers want more functionality from their products, such as convenience, nutrition, good flavor, and longer shelf life. In order to keep up with the everchanging market, new bakery technologies must be developed to meet these challenges, especially the challenge of bread staling.