Source: DAVIDSON, I. Biscuit Baking Technology. Source: Wrigley et al., Encyclopedia of Grain Science, Cookies, Biscuits, and Crackers. working and training in the manufacture of biscuits, cookies and crackers. Each manual provides a Biscuit, Cookies, and Cracker Manufacturing, Manual 4. download Manley's Technology of Biscuits, Crackers and Cookies - 4th Edition. Print Book & E-Book. DRM-free (EPub, PDF, Mobi). × DRM-Free.
|Language:||English, German, Dutch|
|Genre:||Academic & Education|
|ePub File Size:||15.34 MB|
|PDF File Size:||11.18 MB|
|Distribution:||Free* [*Sign up for free]|
Part 1 Management of technology: The technical department; Total quality management and HACCP; Quality control and GMP; Process and efficiency control;. Woodhead Publishing Series in Food Science, Technology and Nutrition: Number Mauley's technology of biscuits, crackers and cookies. Fourth edition. Related titles from Woodhead's food science, technology and nutrition list Technology of biscuits, crackers and cookies Third edition Duncan Manley 'Clear, .
Chapter 1: Setting the scene: A history and the position of biscuits Abstract: Management of technology in biscuit manufacture Chapter 2: The role of the technical department in biscuit manufacture Abstract: Quality control and good manufacturing practice GMP in the biscuit industry Abstract: Process and efficiency control in biscuit manufacture Abstract: Product development in the biscuit industry Abstract: Sustainability in the biscuit industry Abstract: Materials and ingredients for biscuit manufacture Chapter 8: Choosing materials for biscuit production Abstract: Wheat flour and vital wheat gluten as biscuit ingredients Abstract: Meals, grits, flours and starches other than wheat Abstract: Sugars and syrups as biscuit ingredients Abstract: Fats and oils as biscuit ingredients Abstract: Emulsifiers surfactants and antioxidants as biscuit ingredients Abstract: Milk products and egg as biscuit ingredients Abstract: Dried fruits and nuts as biscuit ingredients Abstract: Yeast and enzymes as biscuit ingredients Abstract: Flavours, spices and flavour enhancers as biscuit ingredients Abstract: Additives as biscuit ingredients Abstract: Chocolate and cocoa as biscuit ingredients Abstract: Packaging materials for biscuits and their influence on shelf life Abstract: Types of biscuits Chapter Classification of biscuits Abstract: Cream crackers Abstract: Soda crackers Abstract: Savoury or snack crackers Abstract: Matzos and water biscuits Abstract: Puff biscuits Abstract: Hard sweet, semi-sweet and Garibaldi fruit sandwich biscuits Abstract: Short dough biscuits Abstract: Deposited soft dough and sponge drop biscuits Abstract: Wafer biscuits Abstract: The position of biscuits in nutrition Abstract: Miscellaneous biscuit-like products Abstract: Biscuit production processes and equipment Chapter Bulk handling and metering of biscuit ingredients Abstract: Mixing and premixes in biscuit manufacture Abstract: Sheeting, gauging and cutting in biscuit manufacture Abstract: Laminating in biscuit manufacture Abstract: Rotary moulding in biscuit manufacture Abstract: Extruding and depositing of biscuit dough Abstract: Biscuit baking Abstract: Biscuit cooling and handling Abstract: Secondary processing of biscuits Abstract: Biscuit packaging and storage Abstract: Recycling, handling and disposal of waste biscuit materials Abstract: Widely regarded as the standard work in its field Covers management issues such as HACCP, quality control, process control and product development Deals with the selection of raw materials and ingredients.
Biscuit, cookie, and cracker manufacturing plants, bakers. Do not rush. A few careful trials are worth many rushed and careless ones. Do not make do with poor equipment. The scales for weighing should allow you to measure to 3 significant figures.
Do not make the size of the trial too small. There should be enough samples for several people to be able to see and taste your work when it is good. Do not be worried about wasting ingredients. The cost of these is small compared with your time and the benefits to the company when you have succeeded. There is always a better way of doing something, search for it and try to do it. Achievement satisfies everyone! A glossary of ingredient terms may be found in Appendix 1.
Recipes and Formulations. Applied Science Publishers, London. Woodhead Publishing, Cambridge. Ingredients 2. Biscuit Doughs 3. Biscuit dough piece forming 4. Baking and cooling of biscuits 5.
Secondary processing in biscuit manufacturing 6. Biscuit packaging and storage. Penguin Books Ltd, London. This page intentionally left blank 2 Classification of biscuits 2. Biscuits are no exception! The cereal component is variously enriched with two major ingredients, fat and sugar, but thereafter the possible composition is almost endless.
Technology of Biscuits, Crackers and Cookies
Some problems come in defining the boundaries between biscuits and cakes, or between biscuits and sugar confectionery. One may reasonably consider that boundaries are unimportant: Groupings of biscuits have been made in various ways based on: Method of forming of the dough and dough piece, e. The enrichment of the recipe with fat and sugar. Another classification may be used to describe the secondary processing that the baked biscuit has undergone. Examples are: Chocolate coated.
Iced half coated with a sugary slurry that has been dried.
Manley’s Technology of Biscuits, Crackers and Cookies
Added jam or mallow or both. The result is that the same English adjectives have come to be used in different contexts for different biscuits. Rather than trying to untangle or describe these groupings it is felt best to emphasise that there is overlap and to show, with the aid of figures, how various common types of biscuits are classified relative to one another based on enrichment and the amount of water thereby needed to form a dough.
All recipes except sponges and wafers Units of fat to units of flour 80 70 60 Savoury cracker doughs Extruded and deposited doughs 50 40 30 Plain cracker doughs Moulded and sheeted doughs 20 10 0 0 Continental semisweet doughs Developed semisweet doughs 10 20 30 50 60 70 90 40 80 Units of sugar to units of flour 2. Classification of biscuits 2.
In order to do this one must firstly look critically at the surfaces, particularly the edges and the base, to identify whether, for example, the dough piece was cut, moulded or extruded.
The method of forming is limited by the enrichment of the formulation. The pattern on the base is formed during baking. Doughs rich in fat and sugar bear much stronger impressions from a baking wire than less enriched doughs where the gluten has been developed during mixing.
Internal investigations will reveal a laminar structure in many biscuits with a developed gluten and a more crumbly and more irregularly open structure in doughs with higher fat and sugar. Figure 2. It is necessary to explain how Fig. In all cases, recipes are of biscuits which have been commercially produced within the last 30 years.
The recipes are of doughs mixed before various late additions have been made such as garnishing sugars, salt dusting or egg washes. They are not therefore a representation of baked biscuit composition but of basic mixed doughs.
The fat values of fresh and dried full cream milks have been included even though they are usually of insignificant amounts. Also, the fat content of fresh cheese and cheese powder, although not common ingredients, has been added to the total fat.
Sometimes this means the amount relative to parts of flour, as has been used here, but more correctly it should be relative to the total dough weight, plus or minus added water.
Basing recipes on units of cereal materials means that changes can be made to individual ingredients, such as sugar, water or an aerating chemical, without having to recalculate all the others to get true percentage values. Values used are all relative and are not confused by difficult traditional This page intentionally left blank Classification of biscuits 13 units like sacks of flour, barrels of fat, parts per million, ounces, pounds, gallons, pints or fluid ounces.
There is a growing acceptance of the metric system for weighing and it is thus easy to convert the values shown into kilograms or grams to create a mix of the desired size. As fats have specific gravities of less than 1.
For those who use imperial units of weight, temperature, volume and length there are conversion tables in Appendix 2. It is not surprising to see, in Fig. In any search for a completely new type of biscuit it is best to stay within the broad limits that have been tried because there is probably a good reason for the blank areas on the chart or for the limits of boundaries shown for particular types.
One of these may be the need for a balanced recipe. It is found, for example, that a certain level of fat demands a minimum level of sugar to produce an acceptable texture. The greatest fundamental difference between all the biscuit group areas shown is in the existence or otherwise of a three dimensional structure of gluten that imparts extensibility and cohesiveness to a dough. There is a big difference in the way that short doughs can or must be handled and formed compared with those with extensible gluten.
By and large, dough pieces formed from short doughs do not shrink after formation and then increase in outline during baking a phenomenon described as spread whereas those with extensible and cohesive gluten tend to shrink mostly in their length after cutting and during baking.
By subtleties of processing it is possible to confuse the distinctions which are recipe related described above. Thus we return to the basic problem of precise classification mentioned before. Sections of the enrichment graph as shown in Fig. Superimposed on this pattern of types, which is based on enrichment of recipes with fat and sugar, come other aspects which tend to make the biscuits more interesting or exotic.
Thus layering of fat in a low sugar dough gives puff biscuits. Layering of fruit between an extensible dough gives sandwiches such as Garibaldi biscuits.
Moulding of short dough around a fruit paste gives fig rolls. Coextruding two dissimilar doughs or coextrusion involving a fruit, nut or chocolate centre gives biscuits with distinct dichotomy of textures and flavours. Decoration of the dough piece surfaces with such ingredients as salt, sugar, nuts and egg wash improves appearance and flavour. After baking, the biscuits may be fat sprayed mostly savoury types , sandwiched with sweet or savoury fat creams or marshmallow, or variously enrobed with chocolate, chocolate substitutes or water icings.
Descriptions of these types and processes are included in subsequent sections. Computed aqueous volume v fat Units of fat to units of flour 80 70 60 50 40 30 20 10 0 0 10 20 30 50 60 70 90 40 80 Units of aqueous volume to units of flour 2. If the sponge is moist when packed, as that in Jaffa Cakes, it is technically a cake even if it has been made on biscuit equipment, but if it is dry like that in ladyfingers perhaps it is a biscuit!
Wafer biscuits represent a special type of baked product because they are formed between a pair of hot plates and not on a baking band or wire as are most other types. The recipe is simpler, low in enrichment with fat and sugar, and is mixed to a fluid pumpable batter. Most wafers are rather uninteresting to eat on their own but they form useful, rigid carriers for other more flavoursome mixtures such as sugar cream, caramel toffee and marshmallow.
Wafer batters with higher levels of sugar can be rolled after baking and before cooling. After cooling they are harder and much more palatable to eat than the other flat sheet wafer types. When a large amount of independent information is collected together as a database it is interesting to analyse it to see if relationships and correlations exist that may help in understandings or predictions. For example, it is always a problem to know how much water is needed to make a dough.
Figures 2. For Fig. It will be seen that there is a general relationship that the higher the fat content the lower the water content. Unfortunately, the spread of the results is very large. There are many reasons for the deviations from a precise correlation and some of these are: Variations in, and unmeasured, consistencies of doughs.
A spread of dough temperatures which affect the consistency and therefore the need for water level adjustment. The occasional use of significant levels of biscuit rework material. It was therefore thought that by calculating the new effective volume of water as a result of the sugar dissolving in the dough perhaps a better correlation between dough water and fat content could be found.
In many recipes there is not enough water to dissolve all the added sugar: The correlation has not improved significantly as a result of this manipulation of the values. Other aspects reviewed from the recipe database have been the levels of chemicals, particularly sodium bicarbonate, ammonium bicarbonate and salt that have been used in the various types of biscuits.
These are summarised where appropriate. This page intentionally left blank Classification of biscuits 2. All these processes are described in detail along with the machinery used in the publication Technology of Biscuits, Crackers and Cookies1 but a brief outline will be given here as the relevant techniques are mentioned for each of the recipes given later.
Sheeting involves the continuous compression of a mass of dough into a layer of more or less uniform thickness. On biscuit plant the width of the sheeted dough is normally the same as the general width of the plant, that is, , , , , or mm. When the thickness is thin enough to form dough pieces the sheet passes under cutters which make the pieces.
Manley's Technology of Biscuits, Crackers and Cookies
These pieces are separated from the surrounding dough known as cutter scrap and pass forward to be placed onto the oven band for baking. The cutter scrap is normally returned to the sheeter and reincorporated with fresh dough as the sheet is formed.
The pile of dough layers is subsequently reduced in thickness ready for cutting by passing through a series of gauge rolls. The laminating procedure develops a structure in the dough which is enhanced during baking especially if fat, flour or a mixture of these two is distributed between the layers as they are piled up.
Sheeting and cutting are processes used mostly for hard, developed doughs which exhibit some extensibility. Such doughs are relatively low in fat and sugar. This dough piece forming technique can be used for short doughs but the non-extensibility of short doughs makes it much more difficult to transfer the dough sheet between machines so only one gauge roll after the sheeter and before the cutter is recommended.
There are a few advantages of sheeting and cutting over the normal moulding method for making short dough pieces but very few manufacturers now use sheeting and cutting for their short doughs.
Rotary moulding is the principal method used for making dough pieces from short dough. It has the great advantage that only one relatively simple machine is needed to convert a mass of dough into dough pieces ready for baking.
Rotary moulders are not suitable for very soft doughs or for doughs containing large particles such as nuts, chocolate chips and dried fruit. Softer doughs and doughs with larger pieces included are extruded. Again, only one machine is involved and the extrusions, which of course are determined in outline by the shape and size of the holes in the die plate, may or may not be cut into pieces with a reciprocating wire and then the technique is known as wire cutting. Alternatively, the extrusions may form a continuous ribbon or bar which can be cut into lengths either before or after baking.
The extrusion process also allows coextrusion. Usually, this process is limited to places where there are only two materials such as dough surrounding a central extrusion of fruit paste or one dough within another. Other configurations are possible.
A special type of extrusion is known as depositing. Here the dough is very soft, usually as a result of a high fat content or because the dough is a egg batter.
The extrusions are intermittent through a row of nozzles mounted in a depositor head. The depositor head rises and falls, relative to the accepting surface underneath, and discrete amounts of the dough form as pieces to be baked. The nozzles may rotate or oscillate giving interesting shapes to the deposits formed. This page intentionally left blank 3 Dough consistency 3.
It functions as a catalyst because it is almost totally removed during the subsequent baking process. Water hydrates ingredients like flour and, if conditions are right during subsequent mixing, hydrated wheat protein changes into a viscoelastic material known as gluten. This is very important in determining the nature of the dough, how the dough behaves in the forming processes and ultimately the structure in the baked biscuit. Water also allows the solution of some ingredients such as sugar and, in the case of chemicals, permits reactions to take place in the dough.
However, the amount of water that is added is related principally to the consistency of the mixed dough and it is the problem of achieving the correct consistency that is the subject of this section. Biscuit dough forming machinery the principal processes have been outlined in section 2. Unlike manual techniques, machines are not able to adapt their treatment of dough according to changes in the consistency.
This means that for modern doughforming processes optimum consistency and a continuous maintenance of this dough consistency are essential if the machinery is to perform reliably. The alternative is that plant operators or feedback sensors must continually 22 Biscuit, cracker and cookie recipes adjust the machinery settings to accommodate consistency changes.
This is not a satisfactory situation for ideal process control. Dough consistency is very difficult to define and measure. It is manifest as the softness, stickiness, elasticity and extensibility that can be assessed by manipulating a mass of dough in the hands. This physical condition results from the ingredients of the dough, including the amount of water which has been added, the mixing conditions and the temperature.
Generally, the greater the liquid component in the dough and the higher the temperature the softer will be the dough. The liquids are either water including water in syrups, milk, egg and so forth and fat. The fats used in biscuit doughs are generally semisolid like butter. Crystals of fat are dispersed in liquid fat often known as oil when in the liquid state. Fat crystals melt as they are heated so the amount of liquid is a function both of temperature and of type of fat.
During the mixing of the constituents added water becomes distributed in a number of different ways all of which significantly contribute to the nature of the dough: Hydrated wheat protein may be changed into gluten, as was mentioned above, and this gives the dough a cohesive nature. The absorption is time-dependent and coarse particles like oat flakes take longer to hydrate than does powdery flour.
The formation of gluten depends firstly on the hydration then on a period of mixing so this is both time- and energydependent. It dissolves sugars, chemicals and other substances to form solutions. The dissolution of sugars, principally sucrose, effectively increases the volume of the liquid phase by a factor of 0. The solution of the sugar is quicker than the hydration of the flour so a dough at first becomes more sticky and then, as this syrup is involved in the cereal hydration, the stickiness becomes less apparent.
As the chemicals dissolve, reactions between them and other ingredients become possible and the pH of the dough may change. Generally, higher pH values, as a result of solutions of ammonium bicarbonate and sodium bicarbonate for example, soften gluten and lower the consistency of the dough. It contributes to the liquid phase in the mass together with liquid fat. The fat may coat cereal particles in the initial stages of mixing and retard the hydration and the formation of gluten.
Mixing is often a rather crude process involving the blending and working of all the ingredients placed haphazardly together.
Furthermore, as mixing proceeds there is a development of heat in the dough which increases reaction speeds and affects consistency. It is therefore difficult to be sure in what Dough consistency 23 order or to what degree of completion the above mechanisms, that involve the incorporation of water, have reached.
The aim of mixing is to produce a dough which is homogeneous and of a consistency suitable for further processing. The problem is that this consistency is not stable. The stickiness may decrease as the hydration process continues and the firmness of the dough increases due to a phenomenon known as thixotropy.
In thixotropic materials the consistency is related to the immediate history of that mass. A good example is toothpaste: Another is tomato sauce which is firm in the bottle but becomes much more fluid after the bottle has been shaken! It is very difficult to measure critically the consistency of thixotropic materials because they have to be worked in a prescribed way immediately before the test is made.
For this and other reasons instruments used for assessing dough consistency of biscuit doughs with their great variety of ingredients are generally rather unsatisfactory.
The main reason why doughs appear different after what was apparently a standard mixing procedure is that the metering of the ingredients was not precise. The most likely problem is that while the metering of flour is accurate, varying inclusions of scrap dough or biscuit recycle materials can give big changes to the consistency.
From time to time, but not from batch to batch, the water absorption characters of the flour will change. This means that more or less water is needed to give a desired consistency of dough. The factors that affect flour water absorption are principally the flour moisture content, its protein level, and the amount of damaged starch.
These properties can be controlled by the flour miller. It is very likely that the water absorption of flour will differ if it originates from different flour mills. The effect of changes in flour water absorption on biscuit doughs will generally be minimal except for those with very low fat and sugar contents such as crackers where the dough water requirement is relatively high. It is possible to use specialised dough rheology instruments to measure flour water absorption values but the biscuit makers are not interested in the flour per se: It is not common to measure biscuit dough consistency but penetrometers can give empirical results which may be slightly better than the manual squeezing and stretching test used by experienced operators.
Changes in the dough temperature can also affect the consistency. It is common to mix doughs on a time basis. This means that when the mixer bowl is cold the dough will be cooler after a given mixing period. Mixing of developed doughs should be to a final temperature and not to a time: Please see notes about mixing in each of the recipe sections.
The dough temperature may change in the period of handling before it reaches the forming machinery, it may cool at the edges of a tub left in a cold place or it may be different because it has been used sooner than normal after completion of mixing.
Short doughs have a minimal mixing after the flour has been added. At the end of mixing insufficient time has elapsed for the flour hydration to have been completed. This means that the dough is soft and sticky. Within about 30 minutes of standing the consistency will have changed significantly and although the change continues for much longer the size of the change is thereafter relatively slow. Dough passing through a forming machine that is significantly changing in consistency can be expected to give operation problems so it is highly recommended to stand the dough before use.
The effects of changes in dough consistency are noticed principally on the forming machine. A soft dough will pass more easily through a sheeter and gauge rolls and give a thinner sheet.
If the rolls are cold this will chill and toughen the dough, and as the cutter scrap dough is reincorporated the consistency will be toughened because this dough is always more dense than fresh dough. Cutter scrap can therefore be a problem at start-up and certain other times during plant running if not handled thoughtfully.
The most important single parameter in controlling baked biscuit quality is the weight of the dough piece. Heavier dough pieces will give thicker biscuits, paler bakes with high moisture content and the shape may differ.
It is an essential task of process control to maintain a correct biscuit weight and this is done by controlling the dough piece weight. If the dough consistency is changing, operators of the forming machinery, whether of sheeting and cutting, moulding or extrusion, will have great difficulty in maintaining constant dough piece weights. There are practically no in-line dough piece weight monitoring instruments so automatic feedback to compensate for dough piece weight variation is not at present a practical option.
This was discussed in Section 2. The conclusions may be summarised as follows: Doughs where there is more sugar present than can dissolve in the available water will show a strong softening effect as the temperature rises. This is because more sugar will dissolve and there is a general softening of dough due to higher temperature.
Thus short doughs in summer Dough consistency 25 conditions where the temperature is not controlled will probably need significantly less water. It is well known that the greater the water level in short doughs the better is the structural development during baking, so if the dough is warm and the water level reduced the structural development may be affected.
It would be useful to be able to adjust the dough water level before the completion of the mixing to achieve a desired consistency. Much attention has been applied to this idea.
Many experiments were made by the author and colleagues when they worked at Baker Perkins now APV Baker using the whole mixer as a type of farinograph.
The power taken by the motor during mixing was plotted against time and the shape of the curve noted against a standard when dough of desired consistency had been made. It will be appreciated that the motor is extremely load sensitive so errors of metering give exaggerated results. Also it was found that the ways in which the doughs came together at the early stages of mixing varied and there seemed to be differences in the way the mixer moved the dough from time to time.
Generally it was found that the technique was not useful for controlling dough consistency; however, the technique was useful for detecting differences between batches of dough. These differences arose principally because of errors in ingredient metering.
Such a dough quality monitoring system may be very useful where entirely automatic loading, mixing and discharging systems of dough making are involved.
This involves the rapid measurement of dough moisture content. The idea is that this is a check on both recipe and dough consistency. From what has been told above and displayed in the charts it can be seen that the value of this test is, at best, marginal. This page intentionally left blank 4 Baking techniques 4. It is hoped that with the notes to be found in this book on recipes, mixing techniques and dough consistency the developer will be able to reach a good starting point quickly.
It remains to give some consideration to baking techniques to avoid misunderstandings and disappointments. Most biscuits are now baked in tunnel ovens where there are at least two zones with independently controlled heating systems. In a test bakery it is more likely that a static oven is used and in this case it is not possible to change the heating conditions during the bake time. Baking involves three major changes to the dough piece in its transformation into a biscuit.
These changes are: All of these changes are accomplished by the supply of heat to the dough piece. If the heat is not supplied at the optimum rate one or all of the desired changes will be different from that which is the target. This means that even if the recipe and dough preparation processes are good or correct it may be that the baked biscuit is disappointing due to unsatisfactory baking.
The developer may think that it is the recipe that is at fault and spend much time with changes to the recipe and still fail to make the desired product. Consideration of what happens in the oven and how the controls should be set to achieve optimum results is therefore most important in product development.
The extraction. The baking time for biscuits is usually less than 10 minutes so to obtain reproducible results it is important that the door of the warm oven is not open for too long for loading and that the head space the distance between the dough piece and the top of the oven is small.
There is no indication of heat transfer rate at the dough piece and most of the heat will be supplied as radiant heat.
The extraction, to remove moisture derived from the baking biscuit, is with a crude damper in a flue pipe and the calibration is neither linear nor precise. It will be appreciated that control of the heating conditions in a typical static oven is not very precise and depends almost entirely on the temperature of the oven structure when the pieces were loaded.
There are some static ovens which have forced convection and this means that air is circulated around the oven chamber and over the heating elements. Theoretically, this makes the heating much more uniform between top and bottom of the oven and also from side to side. Instead of radiant heat most of it is supplied as convected heat. However, it is unlikely that the speed of the air flow can be controlled so it may be that the draught of hot air will dry the surface of the dough piece too rapidly to allow optimum internal development before the dough piece surfaces are set firm.
In each zone of a tunnel oven it is possible to set: Possibly the amount of forced circulation, depending on the type of oven system. The power to each zone is controlled by thermocouples sited somewhere in the zone. The indicated temperature in the zone is probably from only one thermometer positioned in that zone. Whether the temperature is truly representative of the temperature near the dough piece is very questionable. Heat is supplied to dough pieces as a combination of conducted heat from the oven band , radiant heat from the walls of the oven and glowing burners Baking techniques 29 and convected heat air moving in the oven either by forced convection or as a result of draughts from live gas flames or currents being drawn to extraction ducts.
It is almost impossible to measure the relative amounts of heat from the different sources or indeed the total heat flux at the surfaces of the dough piece. Extraction is required to remove the products of combustion and water vapour from the baking dough pieces. The extraction may be by natural convection or, more usually, forced by a fan in the flue pipe. The amount of extraction is usually controlled in a crude manner with a damper in the flue pipe. It is quite common for there to be too much extraction so that cool air is drawn into the mouth or exit of the oven effectively reducing the baking time or from adjacent zones.
If oven extraction is excessive there is also a waste of heat energy. Setting the extraction tends to be an art rather than a scientific skill. Forced convection is particularly useful in the further zones of the oven as it improves heat transfer and helps the drying process. It is a difficult process to remove the last amounts of moisture that remain in the centres of baked biscuits. The important point to realise is that using the controls and instruments provided with ovens it is difficult to set the heat transfer regimes that may, in theory, have been decided to be ideal for a product.
To give temperature profiles for baking is of very limited use because they depend upon where the thermometers are situated and the nature of air movements in the oven. Tests to measure temperatures in ovens by passing recording instruments through at the same time as dough pieces show dramatically how inadequate are the static thermometers placed in the oven for indicating baking conditions. It must also be remembered that thermometers do not reveal the heat transfer potentials as this is a combination of radiant, convected and conducted heat collectively known as heat flux.
It is impossible to be precise because no two ovens perform the same. Before setting the oven temperatures and other controls the bakers should try to visualise how heat will be transferred to the baking dough piece and control the relative effects of radiant and convective heat as necessary and possible.
They should remember that the extraction must prevent a pressure build-up 30 Biscuit, cracker and cookie recipes in the oven but not be so great that cold air is drawn in at the mouth and exit or be so excessive in one zone that heat is drawn from adjacent zones.
Generally, the temperatures in the oven should rise to a peak somewhere in the centre of the oven and then fall towards the exit.
If a drop and then a rise in temperature occurs during the bake it is likely that the developing structure will collapse and not be reformed. It is very difficult to scale up baking settings used in a test bakery static oven to a tunnel oven: If there is a window in the static oven it is useful to watch what happens in terms of development and colouration while dough pieces are baked at different starting temperatures or at different levels of convection so that the results from a tunnel oven can be matched as required.
Remember that the results of baking dough pieces of varying weight may be very different. Baking and cooling of biscuits, Woodhead Publishing, Cambridge.
They can, to varying degrees, be pulled out and suspended. There are a number of subdivisions which are shown on the enrichment graph Fig.
It will be seen that in all cases the levels of fat and sugar are low or relatively low. In order to make a manageable dough a considerable amount of water has to be used and this water hydrates the flour proteins and, by mixing, gluten is formed.
It is the gluten that gives the doughs their elastic and extensible characters. With very few exceptions dough pieces are formed from all these doughs by the techniques of sheeting and cutting.
A major process control problem is the maintenance of biscuit size and shape because the gluten in the dough is more or less elastic and the dough piece shrinks after cutting and during the early stages of baking. The amount of this shrinkage is a function of the flour quality, the modification to the gluten quality that can be made during mixing by the use of chemicals and enzymes or by fermentation with yeast and lastly, the amount of dough relaxation that is given before cutting.
This page intentionally left blank Recipes for hard doughs 33 As these doughs all require much water for their formation another processing problem is the adequate removal of this water during baking. The later stages of baking that principally involve drying are very critical because if there is a large moisture gradient between the centre and edges of a biscuit when it leaves the oven subsequent equilibration may result in spontaneous cracking, a phenomenon known as checking.
As the recipes of products in this group are relatively cheap in terms of ingredients it is unsurprising that its members are found very widely throughout the world and most manufacturers produce at least some of the types.
Crispbread recipes shown Units of fat to units of flour 30 20 10 0 0 10 20 Units of sugar to units of flour 5. The two biggest representatives are crispbreads and pretzels. The enrichment of pizza, crispbread and pretzel recipes is shown in Fig. Pizzas are not biscuit products but they are mentioned here because biscuit plant may be used to prepare the pizza bases by the process of sheeting and cutting. The dough pieces are partially baked then topped with tomato paste, cheese and other ingredients before being chilled or frozen.
Final cooking is done just before the pizzas are consumed. Type product wholemeal wheat flour rye flour salt fresh yeast added water 1 crispbread 2 crispbread Mixing Recipe 1 is made from an aerated dough and recipe 2 is fermented with yeast.
For the aerated dough a density of about 0. This is achieved with an Oakes type, high shear continuous mixer. Disperse the yeast in some of the water. Dough piece forming Crispbread doughs are exceedingly sticky due to the rye flour, the high water content and no added fat. The method of sheeting is very special and the product is usually baked as a complete sheet which is sawn into pieces after the oven. Some details of production techniques can be found in Bressler.
The enrichment of these crispbread recipes is shown in Fig. Type product 3 pretzel sponge flour, medium fresh yeast added water dough sponge dough flour, weak dough fat salt fresh yeast added water Mixing One stage for straight doughs, two stages for sponge and dough method.
Recipes 4 and 5 involve a sponge and dough technique and 3 is a straight dough. Disperse the yeast in some of the water and keep away from salt in the straight dough. Dough handling Sponge doughs are fermented for 5 hours or more and the subsequent dough for only a short time.
Dough piece forming Traditional pretzel knots were formed by hand from continuous extrusions as for pretzel sticks see below. Now they are normally formed by sheeting and cutting or by rotary moulding. Removal of the centre pieces of unwanted dough after cutting requires some engineering ingenuity and various techniques are used. After cutting, the dough pieces pass through a lye bath.
The dough pieces are in the warm lye for up to only 20 seconds but this is enough time for the alkaline solution to produce a skin of starch degraded to dextrin and it is this that gives the characteristic dark brown and shiny surface during baking. After passing through the lye bath, and before baking, it is normal to dust with a small amount of coarse crystal or flake salt.
The enrichment of pretzel recipes in given in Fig. This page intentionally left blank Recipes for hard doughs 5. Mixing Ingredients all in together. Doughs to be rotary moulded must be much tighter lower water content than those for sheeting and cutting. Dough handling It is not normal to allow any fermentation time and the quality of the product is generally harder and more dense than the sheeted products.
Dough piece forming Rotary moulding. The dough pieces pass through a lye bath and may have salt applied before baking in the same way as for the sheeted products in 5. Mixing One stage. Dough handling About one hour fermentation.
Dough piece forming By extrusion. The dough is softer than for sheeting and cutting and is continuously extruded through nozzles of about 4 mm diameter. Before baking a cutter nicks the ropes making a partial cut as the ropes are too soft and sticky to make a complete cut and the sticks easily break at these points after baking. The enrichment of pretzel sticks recipes is given in Fig.
Only a minority use ammonium bicarbonate and where this is so the average amount is 0. Surprisingly few recipes use sodium bicarbonate so product pH control is clearly unimportant.
All use salt in the recipe and at the high average level of 1. This means that many of these products are very salty in taste because salt is often applied as a topping before baking. Full coating of crispbreads with chocolate has been known but is currently rare or non-existent. Cream crackers Units of fat to units of flour 30 20 10 0 0 10 20 Units of sugar to units of flour 5. The recipes are low in sugar, most of the doughs are fermented with yeast and are processed to give products with a dry flaky character.
The flavour of the crackers is said to arise significantly from the products of fermentation so those made by long fermentation can be expected to have stronger flavours than those with short fermentation. During long fermentation not only does the added yeast grow but also the adventitious microflora, mostly bacteria, present in the flour.
Long standing times for dough are very inconvenient and there is no knowing how much activity will arise from the flour microflora. For these reasons a continuous fermentation technique is now available to standardise the flavour development and to reduce the dough holding times. The enrichment of crackers, water biscuits and puff biscuits is shown in Fig. The original character of a large square cracker with a soft flaky structure has often been lost and many products called cream crackers are not like this.
Crackers like Hotel crackers have the same structure but are smaller. The recipes and details given here are for more or less typical cream crackers. A range of enrichment of cream cracker recipes is shown in Fig. Recipe no. The hard fat ensures that the mass is not sticky and lumpy. Critical ingredients Flour strength. A bread flour is normally used. The use of proteolytic enzyme is to weaken the dough to improve sheeting.
In long fermentation the microflora provides the enzyme action. Mixing One stage for straight doughs, two stage for sponge and dough method. Recipe 12 involves a sponge and dough technique and the others are straight doughs. Always disperse the yeast in some of the water and keep away from salt in the straight dough. Dough handling All doughs require a standing time to allow the yeast to ferment. For the sponge dough this may be as long as 16 hours and for straight doughs and doughs after incorporation of the sponge dough, the fermentation time is usually about 3 hours but can be as short as 1 hour or as long as 5 hours.
For short fermentations more yeast must be added to the dough and as a rough rule the fermenting dough should double its volume by the time it is taken for use. Fermenting doughs must be held in temperature- and humidity-controlled areas. Dough piece forming A sheeting and cutting technique is always used.
This encourages separation of the layers during baking and adds fat to the recipe which gives a softer eating biscuit. If this scrap dough is irregularly included in the top of the sheet at the time of cutting the uniformity of colour of baked crackers will be affected. Baking Development of an open structure demands rapid heating of the dough piece.
An open wire mesh band is used which is preheated. Baking time c 3. Soda cracker recipes shown Units of fat to units of flour 30 20 10 0 0 10 20 Units of sugar to units of flour 5.
They tend to be made and eaten in countries that do not have cream crackers. Typically, the crackers are squares but much smaller than cream crackers.
Mixing Always a two-stage, sponge and dough method. Disperse the yeast in some of the water and keep away from salt. It will be noted that the proportion of sponge dough in the whole is greater than for cream cracker and also that it is usual to include some or all of the fat in the sponge dough. Dough handling The sponge dough is fermented for 16—24 hours and the remixed dough stage for about 3—5 hours. Water biscuit recipes shown Units of fat to units of flour 30 20 10 0 0 10 20 Units of sugar to units of flour 5.
After sheeting the dough must be laminated but there is no inclusion of dusting between the layers. Baking Usually on a heavy woven oven band which is preheated before the dough pieces are placed on it.
Bake time 2. The enrichment of soda cracker recipes is given in Fig.
The dough is much harder lower in water than cream or soda crackers and the eating quality is much harder and crisper. Mixing The mix time may be prolonged but the dough is crumbly and it does not form a cohesive mass. Dough handling The dough may be used immediately after mixing or it may be stood for up to 3 hours to allow some fermentation or relaxation of the gluten with the aid of the flour microflora. The dough is hard and tough. The sheeter needs to be strong to handle such dough.
Baking On the lightest possible wire band in the hottest possible oven. Typical baking is for 2. The surface of the biscuit should be strongly blistered. This page intentionally left blank Recipes for hard doughs 51 The enrichment of water biscuits is given in Fig. Ammonium bicarbonate is not used. The essential character of puff biscuits is a very open and distinctly flaky structure.
Puff biscuits are used as bread substitutes crackers or as shells for a cream sandwich. There are also some speciality products based on puff dough that are beyond the scope of this book. Type product flour, strong flour, weak dried gluten dough fat whey powder salt SMS added water layering fat mixture layering fat 23 lemon puff The layering fat must be firm and plastic at the dough temperature.
The mixture has been blended and plasticised. The addition of the flour makes it easier to plasticise the mass and also extends the volume of the layering fat. Mixing There are two basic mixing methods. In one the dough ingredients, except the layering fat, are roughly mixed and then lumps about 30 mm cubes of the layering fat are added and the mixing continues to give a good distribution of these lumps. The mixing must be stopped before the lumps of layering fat break up recipe This is known as rough puff.
In the other mixing method the dough ingredients include a small amount of dough fat and mixing is to a clear dough. There is no late addition of fat in the mixer. Dough handling It is normal to relax puff doughs both before use and as much as possible during the processing of dough piece forming.
It is essential that this relaxation takes place in cool conditions otherwise the layering fat will melt and be less effective.
Dough piece forming A sheeting and cutting method is always used. Laminating is an essential process and as the dough may be firm and cool a cut This page intentionally left blank Recipes for hard doughs 55 sheet laminator is to be preferred. In other cases two sheets are formed and layering fat is spread between these sheets before laminating.
This method allows much more fat to be included in the laminated dough. The dough handles better and the eating quality of the baked biscuit is softer and less crisp.
Dough pieces may be dusted with fine sugar before baking. The structural development during baking means that a very thin layer of dough supports this sugar dusting and allows the oven heat to melt it. The result is an attractive glossy surface of sugar glass. This technique is used for sweet products like Lemon Puff cream sandwiches.
The enrichment of puff recipes shown is given in Fig. Salt is included as a flavour enhancer at the relatively very high average level of 1. Sodium bicarbonate and ammonium bicarbonate are not normally used. Savoury cracker recipes shown Units of fat to units of flour 30 20 10 0 0 10 20 Units of sugar to units of flour 5. Because they are made in a very wide range of shapes and sizes they can be regarded as savoury snacks, nibbles or biscuits for cheese.
These biscuits are characterised by very open textures and soft eating mouthfeel. This texture is created by the action of proteolytic enzyme on the gluten in the dough and the use of high levels of ammonium bicarbonate. Usually they are simple biscuits but sometimes they may be cream sandwiched with a savoury, non-sweet, cream often based on cheese powder.
The enrichment of savoury cracker recipes is shown in Fig. Critical ingredients Amount and activity of proteolytic enzyme relative to dough standing time. Quality and flavour of cheese or cheese powder. Stability of oil used for post oven spraying. Mixing All-in mixing. Where cheese powder is used it is best to blend this powder with the fat before adding the flour and water.
To achieve a good and strong cheese flavour is a difficult task as addition of cheese powder interrupts the dough structure and tends to result in loss of structural development during baking.
Dough handling SMS doughs are used immediately after mixing and should be kept warm. Proteinase doughs must be stood to allow the enzyme to react with the gluten. This page intentionally left blank Recipes for hard doughs 61 Dough piece forming A sheeting and cutting method is always used. Laminating is an option but is not essential.
The dough pieces are often lightly dusted with fine salt before baking. The Mini pizza, recipe 28, is topped with tomato paste and dustings of cheese and herbs before baking. Bacon crackers can be made by laminating a red-coloured dough between two uncoloured doughs. Baking Always on a wire band preferably with preheating. High bottom heat should be used in the first part of the oven. Post-baking Immediately after baking, and while the biscuits are still hot, there is an application of warm oil to the top or both surfaces.
This improves the colouration making it more golden brown and the eating quality. It is essential that high-stability oil is used and coconut oil is recommended.
The enrichment of unflavoured savoury crackers shown is given in Fig. The average amount is 3 units but amounts of up to 5. The sodium bicarbonate levels average 0. The use of proteinase enzyme contributes to the characteristic tender texture of these crackers.
However, there are many recipes that rely on SMS to increase the extensibility of the gluten and this is principally because the reaction of proteinase requires a dough standing time of ideally 3 hours or more. This is not convenient in many factories. As the biscuits tend to be soft eating, the cream should be made with a soft fat compatible with the eating texture of the shell biscuits.
The creams are savoury, i. The prime requirement is a biscuit with a smooth surface which has a slight shine or sheen and an open even texture giving a bite that ranges from hard to delicate. This is achieved by a subtle balance between the requirements of recipe and processing.
When flour with higher protein is used the gluten is not extensible enough it is too tough and elastic and some form of modification technique is required. Usually this is done with SMS, but increasingly proteolytic enzyme is being used. The latter does not act in the same way as SMS but it does produce doughs that are easier to sheet. The most common method of dough preparation involves a vigorous or extended mixing to produce a developed dough.
As a result of the mixing action heat is developed. However, there is another mixing technique common in mainland Europe where the dough is made in a two-stage process similar to that used for short doughs.
Mixing is much less vigorous and final dough temperatures lower. Their baked texture is generally softer and less crisp than biscuits from developed doughs. These doughs usually require less water.
For developed doughs there are maximum levels of fat and sugar that can be used. If these levels are exceeded it is not possible to produce an extensible dough: The following sets of recipes serve to illustrate the lowest and highest levels of fat and sugar that are encountered in biscuits of this group.
They provide useful carriers for very sweet additions such as cream, chocolate and icing applied during secondary processing. The enrichment of semisweet dough recipes is shown in Fig. Critical ingredients Flour quality: The fat should be semi solid and plasticised, if the fat must be added as liquid oil it is desirable to add the sugar as a solution.
As fat level is critical to both the recipe cost and the eating quality of the biscuit the use of some emulsifier like lecithin allows the fat to be more effective in its shortening properties. Despite the name Petit Beurre biscuits do not always use butter!
Flavouring of these biscuits is difficult because the water removal during baking strips out volatile chemicals.
Mixing Normally an all mixing method is used. A two-stage method to allow some dissolution of the sugar in the water or plasticising of block fat is not uncommon.
Disperse the ammonium bicarbonate in some of the This page intentionally left blank Recipes for hard doughs 71 water before adding to the mixer. Keep the acid salts away from the soda if possible. Adequate time must be allowed for dissolution of the sugars, hydration of the flour and development of extensible gluten. Doughs made with proteinase will probably be mixed to lower temperatures and be stood before use.
Dough handling Except where the dough is cured with proteinase the dough should be used without delay and kept warm. Dough piece forming With extremely rare exceptions when rotary moulding is used the sheeting and cutting method is used. In many cases laminating is used but this is only necessary where the extensibility of the dough is not as good as it should be.
In these cases laminating may help a little as it gives more work to the dough and provides some relaxation before cutting. Adequate dough relaxation is required before cutting and this also provides a process control technique for maintaining the correct shape of biscuits due to shrinkage after cutting and during baking.
Occasionally a milk wash or a dusting with sugar is given to the dough pieces before baking. Baking Usually on a wire band but sometimes particularly for Marie a steel band is used. Bake times are about 5 to 6. Keeping the first part of the oven humid will give an attractive sheen to the biscuit surface. Baking to a moisture level of less than 1.This was discussed in Section 2. Sodium bicarbonate and ammonium bicarbonate are not normally used.
Changes in the dough temperature can also affect the consistency. Wheat flour contains proteins including gliadin and glutenin. Set out overall aims for a project and head each trial record with an aim that can be assessed when the product is measured or tasted.
There are very many variables involved in biscuit making. Where both fat and sugar amounts in the recipe are high, they combine to make a soft, syrupy, chewy texture.
Reference Manual on Scientific Evidence: Third Edition
The greatest fundamental difference between all the biscuit group areas shown is in the existence or otherwise of a three dimensional structure of gluten that imparts extensibility and cohesiveness to a dough. Critical ingredients The quality of the egg is important and it is usual to use either freshly shelled whole eggs or carefully thawed frozen fresh eggs.
The expansion of the dough is in a syrupy and fatty medium This page intentionally left blank Recipes for short doughs 89 and the contribution of a gluten matrix and gelatinisation of starch to form a rigid structure is very much less apparent.
- THE DARK TOWER WIZARD AND GLASS PDF
- PIPELINE PLANNING AND CONSTRUCTION FIELD MANUAL.PDF
- ANATOMY AND PHYSIOLOGY AN INTEGRATIVE APPROACH EBOOK
- ORACLE 11G BLACK BOOK BY DESHPANDE PDF
- PDF READER APPLICATION FOR ANDROID
- BICYCLE DESIGN BOOK
- CASP COMPTIA ADVANCED SECURITY PRACTITIONER STUDY GUIDE PDF
- SAMSUNG D8000 MANUAL DOWNLOAD
- MAHABHARAT BANGLA BOOK PDF
- EBOOK IPA SMP KELAS 7 KURIKULUM 2013
- THE BOOK OF QUESTIONS EPUB
- THE RULES OF LIFE PDF