Shelf life freshkeeping solutions for bakery
Consumer’s habits have changed in the last years due to accelerated pace of contemporary life and the amount of information that they are exposed to every day. In relation to food, consumers are demanding for more transparency and convenience. Firstly, they are more health conscious than other generations, and because of this, they want to eat nutritious and natural food and beverage products, without losing high quality. Clean label trends demand the lowest use of chemical additives by the industry, besides using as few ingredients as possible. Secondly, they are busier and have less time to spend going to the supermarket, then they need products with an extended shelf life, retaining sensory characteristics throughout all this period, until the moment of consumption.
Both trends have impacted food and beverage companies, which have pursued new ingredients and methods to reach the consumers’ expectations. In the baking industry, it is not different, more and more companies have incorporated into its formulations alternative ingredients that generate the same technological benefits, as well as deliver essential sensory characteristics, such as softness, crumb structure, resilience, sense of moistness and freshness. This industry’s behavior is a constant challenge and essential for retaining brand loyalty.
In order to meet this demand, enzymes have been highlighted in the market as an effective natural option. They are protein molecules that act as biological catalysts and are generally considered as technological aids in the food and beverage industry, which means that they do not have to be declared on the label.
Physical spoilage in baked goods
In bread and other baked goods, the main ingredient is wheat flour, which consists of starch, gluten-forming proteins, fat, water, minerals, etc.
Starch is present as granules and is the most important carbohydrate in wheat flour due to its water-absorbing capacity, its ability to interact with gluten and its availability as yeast feed. It is composed by amylose and amylopectin molecules.
When heated to a certain temperature, in suspension, starch undergoes to an irreversible transformation called gelatinization. In this process, it happens the granules’ swelling and then, solubilization of amylose, especially, forming a continuous gel in the dough.During dough cooling, stronger interactions occurs among starch chains, creating a steadier structure. Amylose molecules recrystallizes, resulting in stiffening of the gel and initial setting of the crumb. At the same time, amylopectin molecules continue to absorb water inside the granule.
Then, during storage, amylopectin starts to recrystallize and, consequently, to release water. These processes are called retrogradation and syneresis, respectively. Both play an important role in sensory characteristics definition, being related to staling of baked goods, re- sulting in loss of softness and freshness, elasticity, resi- lience and moistness, with increasing crumb firmness. Softness and firmness are important sensory parame- ters that are generally measured by texture analyzer, an equipment whose principle is physically deform a test sample in a controlled manner and evaluate its response.
Resilience is the product’s ability to recover from compression and crumb’s elasticity is the ability to resist bending without breaking. Moisture retention defines characteristics that promote the sense of freshness.
The role enzymes in shelf life
Enzymes catalyze reactions among a type or a group of chemical compounds, what defines their specificity and is used as a basis for their classification and nomenclature.The use of enzymes in baked goods formulations is an ordinary procedure. In general, they are applied in order to improve rheological parameters of doughs. The most used enzymes in this type of product are amylases, that act in starch, leading to increased volume of products, extended shelf life and improved characteristics of crust and crumb. Other examples of enzymes used are prote- ases, lipases, glucose-oxidases, etc.
Alpha-amylases are enzymes that hydrolyzes alpha glycosidic linkages in starch, glycogen and dextrins. They may be synthesized by plants (cereals), fungi and bacteria. In the last years, different types of alpha-amylase have been used by the baking industry, since each one presents different application characteristics and benefits.
The application of fungal and bacterial alpha-amylases is mainly related to structure improvement. This type of enzyme acts on starch chains, releasing dextrins and maltose molecules, which are used as yeast feed and substrate to Maillard reactions. It mainly promotes the production of bread with higher volume and more attractive flavor and crust color.
In relation to shelf life of baked goods, mainly bread and cake, maltogenic amylase arises as a revolutionary clean label alternative to meet the consumers’ demands. It modifies starch granules, acting on amylopectin branches and resulting in an important antistaling effect. The freshness is retained for a longer time, generating sensory improvements in the product and economic benefits for the industry.
Besides amylases, lipases may be beneficial for softness in baked goods. Its application generates better maintenance of sensory characteristics, extending shelf life by the formation of amylose-lipid complexes. These complexes are able to slow up starch retrogradation process, generating an antistaling effect.
The evolution of enzymes for freshkeeping during shelf life
In recent years, there have been changes in the application of enzymes for freshkeeping during shelf life of industrial bakery products, following the development of new technologies. The solutions of enzymes have been increasingly effective in improving elasticity, softness, moisture sense, resilience, cohesiveness and other es- sential quality characteristics for the consumers. Initially, it was applied alpha-amylase extracted from malt. However, the wide difference among different “batches” of enzymes was an issue for the baking industry. Advances in biotechnology allowed the use of standardized products, through the microbial enzymes production.
Fungal amylase presents a medium thermostability, performing in temperatures between 58°C and 78°C. Because of its characteristic, it is inactivated before complete starch gelatinization, then, its higher activity occurs on damaged starch. The baking industry started to demand for innovative solutions in order to enhance the benefits generated by the use of amylases.
Then, bacterial amylase started to be applied because of its higher thermostability. It acts the same way as fungal amylase, randomly hydrolyzing alpha-1,4-glucosidic linkages in amylose and amylopectin chains, but its optimum activity occurs in temperatures between 70°C and 100°C. This behavior allows its action on gelatinized starch and during a longer time in oven. However, at the same time, this characteristic may lead to generation of negative side effects. In the case of overdose or accidental failure in inactivation during baking, it will lead to a very moist, sticky, gummy crumb and absolute lack of resilience. For some products, this characteristic is desired by the consumer and the dosage may be limited to avoid overactivity of the enzyme.
The next step in the development of new technologies in enzymes applied in baked goods arose from studies about maltogenic amylase. This enzyme removes units of maltose, acting from the end of non-reducing starch chain. This specificity of the enzyme is an important differential, that increases its effectivity. Besides this, it is able to act on amylopectin branches, delaying starch retrogradation by preventing molecules approach and crystallization. It presents thermostability between 80°C and 90°C, performing on gelatinized starch and being inactivated in the oven, what avoid over-hydrolysis. Because of its characteristics, maltogenic amylase is highly effective on improving freshness, sense of moistu- re, crumb softness, elasticity and resilience, producing goods with better sensory characteristics and extended shelf life.
However, its application is limited to sugary products: high sugar contents inhibit the enzymatic activity. New studies, based on more advances in biotechnology and bioengineering, allowed the development of a maltoge- nic amylase sugar tolerant. In general, it is a common maltogenic amylase with conformational changes. This variation does not impact on mechanism of action of the enzyme, but avoid the interaction sugar-enzyme. Thus, it is possible to apply the same dose of maltogenic amylase, even in sugary products, such as panettones and special types of bread.
Based on the information described above, it is possible to perceive that enzymes are exciting natural substances that allow the baking industry to produce clean label goods with excellent sensory characteristics during an extended shelf life. They can replace some emulsifiers and be applied in a wide diversity of products, acting in a sustainable way, reducing waste and costs for the industry.