Food Additives that are Being Incorporated into Bread to Reduce StalingThere are few strategies that can be implemented in food processing in order to reduce the rate of bread staling. One of them are by adding antistaling additives into the bread. For examples:
(i) Protein flour (ii) Alpha amylase enzymes (iii) Emulsifier (surfactants) (iv) Lipids (v) Modified starch Flour protein can affect the staling rate of bread by reducing the firming rate. Starch-gluten interaction is the reaction happened that contribute to antifirming activity, by hydrogen bonding between the amide groups of wheat gliadin, glutenin, and possibly albumin and hydroxyl groups of starch. Therefore, the ratio of starch to protein in the dough is essential to determine the rate of staling. Flour’s protein level of staling during storage has inverse relationship. The development of hardness of bread crumb and the rate of firming can be reduce by adding more protein. Staling made up of two stages, first is the retrogradation of starch and followed by moisture loss in gluten. Increasing level of gluten can reduce the staling rate by lower down the association of starch granules by embedded it in the gluten network. Studies also shown that gluten act as a moisture or water reservoir to encounter changes of the hydration capacity of starch (Gray & Bemiller 2003). Besides, addition of enzyme can also help to control the rate of staling process. Most common enzymes used was proteases and amylases which control the development of bread staling and improve the flavour, texture, aroma of bread. If bacterial alpha amylase that is derived from Bacillus subtilis is used in a bread formulation, it can survive under baking temperature and bread will results in a gummy texture. Amylase usually takes place after gelatinazation of starch occur and susceptible to the enzyme. Dextrins, type of maltooligosaccharides which is low in molecular produced by a-amylases helps to prevent staling. It acts by inhibiting the formation of cross-linkage between starch and gluten (Gray & Bemiller 2003). |
Other than that, addition of emulsifier or as being called surfactants or surface-active-lipids is a common ways to reduce rate of bread staling. Antistaling effects done by reducing the retrogradation of amylopectin and forming complexes with amylose at the same time reduce the firming of crumb. These antifirming properties are due to the changes of cell wall thickness and elasticity affected by it. When surfactant is used in combination with monoglycerides, effect of reduction of firmness over a longer period of storage can be achieved (Fadda et. al 2014).
Furthermore, native lipids also contribute to the several properties in baked products. Flour lipid content is inversely related to the loaf volume in which protein-lipid interactions is the mechanisms behind. Shortening is another type of lipids used that can lowered the fimring rate of bread but so not react with starch. Thus, native flour lipids have an effect on the anti-firming action of shortening. Both native lipids and shortening affect firming rates neither have significant effects on starch retrogradation. Complexes between native lipids and amylose were formed within the first few days of storage and these complex formations can reduce the maximum amount of starch retrogradation (Rogers et.al 1988). Last but not least, addition of modified starch can also reduce the staling of bread which is usually done in the bread production since they have one or more of their characteristics changed by treatment. Bread staling the retrogradation of starch upon storage, which expel the water out of starch and water can be evaporated thus giving the bread a firm and undesired texture. To prevent this, some modification can be done to the starch such as pre-gelatinized starches. Cross-linkage might be introduce, this can holds the structure together can prevent too much of water going into the starch during swelling and thus can control the amount of water expelled and evaporated later when retrogradation occurred, this can then prevent the bread to become hard easily (FAO 2013). |