Using enzymes as additives in bread-making is a common practice today, since the enzymes have the same effect as chemical additives with the advantage that they are considered natural. Among the family of enzymes, the most frequently used are amylase, lipase, hemicellulase, pentosanase, protease and oxidase. In general, enzymes are made up of proteins and characterized by their high selectivity and specificity and according to their catalytic activity. This last characteristic depends greatly upon the environmental conditions of the overall system (for example pH, temperature, water activity and ionic force), and upon the origin of the enzymes and the presence of various
molecules capable of modifying the catalytic centre. Furthermore, bread making varies in significant ways according to the quality of the flour used, the type of ingredients and additives used, the process that is followed and the processing conditions. Therefore it is necessary to have a thorough knowledge of the characteristics of enzymes in order to apply them efficiently. The quantity to be used must be optimized in relation to the flour, taking into account the above mentioned factors, so as not to add too much or too little.
Types and applications
As previously mentioned, alpha-amylase is one of the enzymes most utilized in this area because it offers several advantages such as increasing loaf volume and improving the colour and aroma of the bread. In addition it has been noted that this enzyme produces an anti-staling effect thanks to the ability to delay the degradation of amilpectine during the shelf life of the product. Alpha-amylase available on the market has various origins and can be derived from cereals and micro-organisms. To evaluate the effect of the source on the enzyme activity, a recent study was conducted to study enzymes extracted from wheat, barley, fungi and bacteria, which were used to product bread in different processes with different recipes. The results showed a low sensitivity to the presence of different ingredients, additives and metabolizers for alpha-amylase extracted from cereals (wheat and barley) compared to alpha-amylase derived from microbes such as fungi and bacteria. Xylanase also produces an anti-staling effect during the shelf life of the bread but the effects of the action are not as yet completely clear. Various scientific studies have demonstrated, on the other hand, that the use of pentosanase promotes the elasticity of the glutens and, in general, improves the quality of the bread. Glucose oxidase is a valid alternative to oxidising agents.
