Gently Does It For A Top Quality Loaf
Saturday, September 16th, 2017 | 96 Views
High output bread bakeries can now achieve excellent quality economically thanks to developments in mixing and forming technology that focus on gentle dough handling. New ideas also bring added value and variety options for the standard loaf. By Keith Graham, marketing manager, Baker Perkins
‘Food on the move’ has become a fact of life throughout the world, and with it the expansion of supply industries. Bread is one growth sector, particularly the sliced loaf which can be the basis for a rapidly prepared sandwich or toast, at home or in food outlets.
Increased demand inevitably leads to a requirement for higher scale production facilities, and in the bread industry that can mean systems capable of producing several thousand loaves every hour, linked to a sophisticated distribution system.
Companies investing in these plants need to be sure of consistently reproducing the product quality of the low-output, artisan bread facilities they may be replacing while keeping production costs low. Once in production, manufacturers need the ability to broaden their product range.
The solution to these exacting requirements came from research into dough rheology, which showed that by minimising stress on the dough pieces as they are processed, quality improves and ingredient costs are reduced as less yeast and improvers are required to achieve the same bread quality.
Gentle dough handling was clearly the key to superior bread in terms of both quality and value, enabling plant bakers to combine the highest standards with economic production. The more gently dough is treated, the higher the cell count—the number of micro-bubbles retained in the dough structure. The effect is to create a loaf with a fine crumb structure, good texture and an attractive colour.
Carefully handling the dough through the dividing, rounding and moulding phases preserves the integrity of the dough structure, resulting in a loaf with high consumer appeal.
Quality Begins With Mixing
Dependable quality clearly has to begin at the mixer. These can ensure accurate weighing of ingredients and thorough mixing to a specific energy input, producing identical batches of dough.
This consistent quality can be achieved by rapid mixing in small batches under pressure and/or vacuum. Dough quality is enhanced and controlled by applying pressure at the start of the mix to assist with dough development and vacuum at the end to promote the creation of gas bubbles.
Short mixing times, small batches and dynamic scheduling minimise downstream waste, giveaway and downtime caused by dough gassing. Product costs are kept low by water absorption rates up to 75 percent, and the efficient development of the available protein produces strong dough from lower protein flour.
Adjusting To Industry Demands
For the highest quality loaf, the gas cell structure created in the mixer must be preserved throughout the forming process. The key development here was the design of the latest generation of ram and knife dough divider.
The introduction of servo-control to the ram movement permits low pressure operation that minimises product damage and improves loaf quality, as cell count increases as pressure is reduced. The effect is to create a loaf with a fine crumb structure that resists tearing and has a good colour.
The divider minimises cost through consistent scaling accuracy, the most important single attribute. This machine retains the level of accuracy that has set the industry standard for 20 years, over a wide range of products and weights. Standard deviation is just 2.5-3.5 g on an 800 g loaf over 10,000 hours of operations, with no parts being replaced.
The machine also features innovative die design which reduces costs through minimal oil consumption and dough leakage. Wear is reduced by efficient lubrication, minimum ram movement, low pressure operation and long life components (typically 24,000 hours for ram and knife, and 16,000 hours for the die).
Other features combine to bring higher efficiency and lower cost of ownership through longer component life, extended running time, reduced oil usage, and easier maintenance and cleaning.
The latest development is a wash-down divider. All mechanisms between the frames of the divider can be made from stainless materials. Sealed-for-life bearings enable chemical foam-and-rinse cleaning of all areas of the divider where oil and product debris many collect.
Allergens and pathogens are a rising concern for the bakery industry, and are most reliably removed by these methods. Wash-down allows the thorough cleaning the industry now demands: the divider can be wheeled away from the production line to prevent cross-contamination.
Keeping Eyes On Moulding
Moulding, the next stage of the bread making process, is also crucial in maintaining consistency and quality. Here, the latest generation of moulders incorporate the concept of four pairs of close-coupled sheeting rollers—research findings showed that a higher number of small diameter sheeting rolls reduces dough damage.
This arrangement improves end-product quality by controlling size, shape and length-to-width ratio of the dough sheet before coiling. It allows tighter coiling, with more coils, whilst at the same time significantly reduces stress to the dough through a more progressive thickness reduction.
The moulder sheets coil and mould the dough pieces very gently so that they rise strongly and evenly. The resultant increases in volume and cell count of up to 10 percent can give an excellent crumb structure and fine, even texture. The shape, colour and resilience of the slices are enhanced. This effect is so marked that such machines can be used to produce the same quality as other moulders but with lower ingredient costs, because less yeast and improvers would be needed for a given level of quality.
Other benefits include an ability to handle the sticky doughs that result from a reduction of salt in the mix— currently the baking industry is under pressure to reduce salt on health grounds.
With forming machines designed specifically to achieve the gentle handling that preserves the fine cell structure developed in the mixer, the dough proofs and bakes well to achieve the required volume, colour and softness, but at a lower cost. Production costs are further reduced because gentle handling eliminates the sticking and smearing that lead to jams. It also means that lower cleaning and maintenance costs are incurred.
Ingredient costs are reduced as less yeast and improvers are required to achieve the same bread quality. Gentle handling minimises dough damage so more of the cell structure developed in the mixer is retained. The dough proofs and bakes well to achieve the retained volume, colour and softness, but at a lower cost.
Production costs are further reduced because gentle handling reduces jams, meaning that a lot less cleaning and maintenance is required, and further with the automatic mixing bowl system on the mixer and full washdown capability of the divider, these make a big contribution to reducing produce changeover times, which raises production flexibility.
Eliminating the trade-off between cost and quality takes away the headaches caused by conflicting priorities and also increases plant versatility. With simple recipe changes, a single line can produce anything from standard to premium quality bread, all the while keeping costs under control.
Innovations for bread moulders, such as those developed by Baker Perkins, enable bakers to add value and variety to standard loaves by fully enrobing them with seeds or grains, and by creating attractive swirled loaves—or by doing both on the same machine.
Seeding the top, bottom, sides and ends of the loaf (known as fully-enrobing) adds visual appeal to the product as well as value, and supports claims to be tastier and healthier.
Demand for seeded bread is growing strongly and is usually met by simply sprinkling seeds or grains onto the top of the loaf as it exits the prover. However less than 25 percent of the loaf’s surface is covered and there is no way of pressing the seeds into the dough, so a great deal may be left in the bag. There is also waste caused by seeds or grains falling through the gaps between the tins.
The technique to make fully-enrobed loaves involves rolling the coiled dough pieces in seeds or grains before panning. This achieves good coverage and simultaneously solves the problems of pressing the seeds into the dough piece and avoiding waste.
Metered quantities are deposited on the moulding conveyor to be picked up and lightly pressed into the surface of the dough piece as it rotates under the moulding board. There is no waste, and any leftover seeds drop into the pan with the dough piece.
The second innovation incorporates inclusions by interspersing them with the coils of dough. This is the technique used to make classics such as French pain-au-raisin and American cinnamon swirl, and has many advantages compared with simply mixing the inclusions into the dough.
Concentrating them in thin strata rather than being widely dispersed creates a much more visually interesting product with an intense flavour hit. Damage to delicate inclusions such as seeds, nuts, dried fruit and chocolate chips is avoided and it is possible to use fillings that would adversely affect texture if mixed into the dough.
Swirl breads with cinnamon or raisins are well established and can readily be made on the moulder, but bake stable powders and inclusions such as seeds, chopped nuts, dried fruits and chocolate chips are all possible.
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