Technological additives – role and necessity

Technological additives – role and necessity

Technological additives – role and necessity

Main types of improving agents:

Oxidizing agents. The role of oxidants in bread-making systems is that of improving the gas retention abilities of the dough through better gluten development.

With the addition of suitable oxidizing materials to the dough, we can reduce the development time for doughs from many hours to less than 10 minutes and achieve most of the changes in the mixer.

If we use a high-speed mixer we can achieve full dough development in less than 5 minutes.

The benefits of oxidizing agents have been known for over 50 years and many different types have been, and are being used around the world. Slow-acting ones such as potassium bromate have been used widely and were common
throughout Europe.

The faster-acting ones such as potassium iodate, calcium iodate, and azodicarbonamide are more widely used in the USA.

However, with a greater awareness of food additives by the general population and a greater understanding of their function, several changes to legislation in Europe have been made with the result that we are left with ascorbic acid (or Vitamin C or E 300) as the sole oxidizing agent for use in the baking industry.

At present, the level of use is quantum satis use as much as required. These oxidizing agents are commonly added as part of the bread improver, but they can also be added to flours by the miller.

Bakers need to be aware that they do not overdose on bread dough by adding oxidizing agents from several sources. Reducing agents. Reducing agents make the dough more extensible. They are deliberately added to ‘weaken’ structure in specific products.

The major material used in bread dough is an amino acid known as L-cysteine. It can only be used at low levels in improvers but by reducing dough resistance to deformation it helps in molding and shape forming, such as rolls and baps, without structural damage.

L-cysteine can also be used in pan bread at low levels where its ability to reduce resistance can help reduce streaking caused by molding faults.

Other ingredients such as deactivated yeast and proteases have a similar effect. Reducing agents soften dough by breaking the cross-links between amino acid chains in the gluten network rather than by breaking the chains themselves.

This reaction is finite and so the process is inherently more controllable than that using enzymes. A wide range of recipes use this technology and reducing agents are sometimes used in conjunction with enzymes.

Emulsifiers. Emulsifier is a general term we use to describe ingredients that can assist in the mixing together of two dissimilar materials. A range of emulsifiers may be added to bread to improve its quality, each one acting slightly differently and having its special effects.

We will briefly consider some of them:

– Glyceryl monostearate GMS – has a softening, anti-staling effect
– Diacetyl esters of tartaric acid DATEM – gives better bread volume, not permitted in all countries
– SSL sodium stearoyl lactylate / CSL calcium stearoyl lactylate – effective but expensive
– Lecithin – natural but less effective

Starch complexing agents, emulsifiers, have been used as anti-staling agents for many years (DATEM, SSL/CSL, GMS) to reduce the apparent staling of the bread. Emulsifiers are complex with amylose and inhibit the rate of starch crystallization.

Hydrophilic

– Lipophilic Balance, HLB is a system of classifying surfactants/emulsifiers by how much water-loving or fat-loving character the molecules possess, on a scale of 0 – 20;

some examples: oleic acid 1.0, mono and diglycerides 2.8, DATEM 7 – 8, SSL 10.0. In addition to single emulsifier systems, the use of multi-emulsifier gels in cake making is quite widespread, because mixtures of emulsifiers tend to produce better results than individual materials, and a wider range of HLB can be covered.

Using polyglycerol esters, sorbitan esters, or propylene glycol esters in conjunction with GMS can give further improvements.

Enzymes. Enzymes are biological catalysts – all known enzymes are proteins. They are large molecules made up of chains of amino acids linked together by peptide bonds.

Enzymes’ active materials have assumed greater importance in improver formulations over recent years.

Factors affecting enzyme activity are:

– temperature
– pH
– concentration of substrate
– inhibitors.

Malted barley and wheat flours, often called diastatic malt flour, have been and are still used as an improver by bakers to give better gas retention and other benefits in doughs.

The traditional role for malted barley flour was to improve gas production in long-fermented doughs but today with our more rapidly processed doughs this function is largely irrelevant.

Soya flour has been used as a bread improver for many years. It contains lipoxygenase which ‘bleaches’ the natural pigments in flour to create whiter bread. Other enzyme-active materials have assumed greater importance in improver formulations.

In 1996 the use of enzymes in bread was ‘de-regulated’ – this means that we can use a much wider range of enzymes than before, provided they are safe for use and human consumption.

This will allow the baking industry to make even greater use of the special properties of enzymes for improving dough performance and bread quality. The main enzymes in bread are presented in fig.10.

Cereal α-amylase is naturally present in flour. It breaks the starch into simple sugars to feed the young plant. Levels will vary depending on the quality of the wheat and the weather conditions during harvest.

Cereal α -amylase can be a beneficial bread improver, but at high levels can cause stickiness, most noticeably in sandwich bread; the levels are measured in seconds using Hagberg Falling Number (HFN), where the 60s is a very high level and 450s is a very low level.

Flour millers control the level of flour by blending the wheat. The term alpha-amylase is used to describe a range of enzymes, which are capable of breaking down damaged starch granules into materials known as dextrins, and in combination with beta-amylase, they will produce maltose.

Alpha and beta-amylase work in combination. Beta-amylase attacks the ends of the amylose and amylopectin chains breaking off individual maltose sugar molecules.

Most wheat flours contain adequate levels of beta-amylase so it is the alpha-amylase that controls the reaction. Additions of alpha-amylase to doughs via improvers and even in flour mills are preferred in the fungal rather that the cereal form.

This is because the fungal form is inactivated at lower temperatures in the baking process and reduces the risk of the formation of high levels of sticky dextrins. Excess cereal α- amylase reduces bread quality.

Cereal alpha-amylase is produced during the growing cycle and can achieve quite high levels if the period around harvesting is wet.

The dextrins which are produced by the action of alpha-amylase on damaged starch are sticky and if their level is high enough in the finished bread they build up on the slicer blades and can reduce their efficiency to such an extent that loaves will collapse.

The other widely used enzyme is hemicellulase, also known as pentosanase and xylanase. This was added to the list of permitted enzymes in 1996 and has already achieved widespread use.

They react with a complex group of flour components we call pentosanes which are present in white flour at levels of around 2% of the total flour weight.

The significance of the pentosanes in dough structure becomes apparent if one examines the distribution of water in
bread dough. Although pentosanes represent only about 2% of the total flour by weight, they bind roughly ten times their weight in water.

Hemicellulases help to increase volume, and improve dough handling but have little or no anti-fareffectffect – the overall mechanism is probably similar to that for the amylases, enhancing gas retention and delaying the setting point of the bread in the oven.

Gums. Xanthan gum, Guar Gum are water-binding agents. Bread softness can be influenced by increasing the water content of the crumb, therefore moisture in the dough can be increased (2-3%). For the same purpose, it could be used also stronger flours that have higher water absorption and hydrocolloids.

But there are some problems regarding the use of gums:

– water being a non-structural ingredient can lead to less volume
– increasing water can increase water activity and reduce mold-free shelf-life.

Read more:

• Competency Standards For Food Processing and Quality Control NTVQ, Level 1- 3
• Make Some Batter Bread – FUNDAMENTAL FACTS – PART II
• Foundation Recipe For Sweet Yeast Dough – FUNDAMENTAL FACTS – PART II
• Recipe For Whole Wheat Bread – FUNDAMENTAL FACTS – PART II
• Cob Loaf Recipes