In biological systems, all the conversion processes can take place quickly at relatively low temperatures and mild chemical conditions, because enzymes help to run the reactions with lower energy input.
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FEATURE Additives for flour standardisation - Part I: Enzymes by Lutz Popper, Mühlenchemie GmbH & Co. KG, GermanyI n biological systems, all the conversion gic reactions. Therefore, it is advised that the most enzymes, amylases also act on sub- processes can take place quickly at employees in contact with enzymes should stances that are well in contact with water. relatively low temperatures and wear gloves, mask and goggles. Although Alpha-amylase breaks down unbranchedmild chemical conditions, because with a lower probability because of the moieties of starch molecules, releasing dex-enzymes help to run the reactions dilution in flour or bread improvers, the trins. These dextrins act as substrate forwith lower energy input. same risk is present for bakers. Therefore, beta-amylase and glucoamylase, which in enzyme producers are trying to manufacture turn produce sugars like maltose and glucose Because of the ability to perform very preparations that emit less dust. that can be directly used by yeast. By thecomplex reactions under these mild condi- For a long time, α- and ß-amylase were action of amylases, the dough viscosity istions, enzymes are produced in industrial thought to be the only enzymes that could decreased (water released from the starch),scale, mostly by micro-organisms. The devel- be used in the milling industry. This view has the fermentation power and the volume areopment of new enzymes in short succession changed dramatically since the introduction increased, taste and colour are improved,all around the world is fueled by increasing of hemicellulases two decades ago, and has the crumb softness is retained and the shelfcompetition. High quality and low cost prod- now received another blow through the life is extended.ucts manufactured with the help of these success of lipolyticenzymes have the chance to compete better enzymes. There arein the market. many more enzymes Enzymes are used in many areas of the (Table 1) that stillfood industry. In contrast to most other food play niche roles forapplication, enzymes used in the flour indus- certain applications,try do not show their effects at the moment but which may turnthey are added, that is, right in the mill. In out one day to be asorder to see the effect of enzymes in flour, versatile as the afore-the baker must add water. This problem of mentioned types.time and place is the general challenge in theflour improvement business, but it gets even Amylasesmore complex when it comes to enzymes. The most usedBut enzymes also have definite advantages as types of amylasesthey are specialised on distinct effects, used in flour industryin very small dosages, natural and completely are alpha-amylase,deactivated under baking conditions. beta-amylase and As with all the concentrated natural sub- amyloglucosidasestances, enzymes pose the risk to cause aller- (glucoamylase). Like Figure 1: Enzyme production scheme18 | march - april 2013 Grain &feed millinG technoloGy
FEATURE FEATUREis sensitive machinery, motors or anything As well as being applicable to a wide includes of a 50,000 SKB/g amylase per 100 kg gram the fully auditable dry steam beltelectric and adversely affected by water. range of work settings, steam can be used sanitation unit (BSU) much less native enzyme of flour). There is which cleans conveyor The technology, which is the first of to undertake innumerable cleaning tasks. belts flour with level, saving up to above 400 in to allergen Falling Numbers 3 millionits kind in the UK, uses a continuous flow The system can be used on feeding, mixing seconds, therefore 3 grams or more of the litres of water per annum.heating coil system to heat water to such and blending vessels, machinery, conveyor same organisation has used. developed a The amylase may be also On the othera high degree that it becomes extremely belts, rollers, pipelines and also general floor central steam systemvery low FNproduction hand, in flours with for food values, usinghot vapour. The emitted dry steam contains areas, storage spaces and much more. As and packaging areas. This (like 0.1-0.2 grams trace amounts of amylase is much like aminimal moisture and efficient cleaning capa- it is applied to the surface, dry steam of 50,000 SKB/g amylase) will not affect the central vacuum, which facilitates cleaningbility is produced from the steam pressure leaves very little residue and can byFN but may have the steam effect on the simply plugging a beneficial hoses intomade on the surface area. almost touch dry, especially central steam pipesand volume yield. for dough properties without the need when compared handling cleaning machines. The sophisti-Is all steam cleaning the same? Glucoamylase can be used for the cated equipment So steam is simply steam? Well actually, Also called heavy parts and foror previ- cleaning of amyloglucosidase plasticno. Steam can be produced in a range ously parts cleaning. The machines start gamma amylase, this enzyme breaksof different grades, each matching dif- starch to its smallest single phase unit and from a 3kW building blocks, glucose.ferent industry applications. Picking the It also can work on the144kW units avail- of reach up to branching pointscleaning method best suited to your able in electric, oil or amylopectin, as opposed to alpha-amylase.operation depends upon a number of With this property, glucoamylase coils. gas heated helpsoptions including the nature of the sur- Figure 2: Hemicellulolytic enzymes Kopie improving the browning of baked productsface to be cleaned and the type of material and stabilises the fermentation in prolongedor residue found on crushing or milling appa- fermentation processes. There is no viscos- Enzyme active malt flourratus, conveyors and elevator pits and silos. to any Amylase from fungal sources is mostly ity lowering effect of this enzyme because To date,need enzymes to start with their vital Seeds conventional CIP systems have other clean- alpha-amylase. Most detrimental side activi- it leaves the large starch molecules basicallytended to rely on traditional boiler systems activities, therefore high amount of enzymes ing method. ties are prevented by selection of suitable unaffected, at least within the relatively shortwhich are only required to heat the water step. are produced during the germination to No additional subspecies and processing conditions. At time of baking processes.a maximumbe useddegrees and rely on high Grains to of 75 for enzymatic purposes will ingredientsdosage, fungalin amylase does not normal are requiredwater germinated beforepressure, using a lot be flow and minimal processing. Enzyme- the steam to improve cleaning interfere with FN values because it is not Hemicellulaseof active malt flour is produced from germinated water in the process. power, as efficient cleaning (approx. 95 °C) of stable at the temperature capacity The term hemicellulase designates barley, wheat related sites functions of these Most food or rye. The use hot water is the standard assay. There is another, modi- produced from the steam pressure a family of enzymes. All the membersthat comesare generally similar. products off the boiler through hoses, made FN test to determine be cleaned and fied on the surface to the effect of fungal shown in Figure 2 are able to breakusing Besides alpha- and beta-amylases, there foamers, liquid chemicals and other the solvent which employs drops at a high amylase, power of micro lower maximum down the pentosans (therefore theysanitation agents. They can use between are other enzymes in malt flour, like pro- temperature, with minimal 82 °C. present. temperatures at around moisture are also called pentosanases), but their200-1,000 litres of water While some blast a teases and glucanases. per hour to of these However, dos- Thesurface positive effects on baking, somenega- have clean. They can also have the do the where of specific age alpha-tive side effect of sending dangerous bacteria opposite. Like the enzymes natively found tasks or loca- amylaseairborne, spreading them malt flour also have in flour, enzymes from through the plant tions demand preparationswithout killing them. This ‘wet steam’ system a considerable effect on the Falling Number it, depends on ingredientsdoes not use a vapour process. of flour is very (FN). If the enzymatic activity can be added their activ- low, malt flour up to 150 grams per 100 kg toity. In order improveBenefits of in order to decrease FN values can be used dry steam cleaning the solidifica- to express to 250-300 seconds.capacity is of FN below Efficient cleaning In the case produced tion of specific the activ-from theenzyme active malt made may result 300 s, steam pressure flour on the substances, for ity of alpha-surface to be cleaned andwhen used at below in sticky doughs even the solvent power instance within amylase, theof 50 g per 100 at a The activity of malt flour micro drops kg. high temperature, with liquid fat appli- unit for theminimal moisture present.diastatic power (DP) is mostly stated as the cation method test devices and is continuous steam400 DP. This activity The usually at around system provides which developed couldconstant steam quality as 80-120 SKB/g. may be interpreted which can be adjusted congeal with- by Sandstedt,by volume and dryness. Water flow and out the use of Kneen and Fungal amylaseheating power can be controlled and adapt- additional ingre- Blish (1939),ed byUsually fungi control system. Aspergillus an electronic belonging to dients. SKB, is the genusamount of water saved dependsamylase. The are used to produce fungal upon used. Eventhe flow rate of the water system and the The species are well defined and do not Dry steam though differ-pressure employed, but it can save substances. produce toxic or carcinogenic up to 90 machines ent supplierspercentfungi are used. OspreyDeepclean’s dry The of water grown in large fermentation for different use differentsteam technologyproducing and excreting the tanks end left will typically use between applications test methods,10-30 litres of water per hour, whereasfluid. desired enzymes to the fermentation a the The results tech-conventional system broth containing the raw The fermentation will use between 200- are nology Osprey often1,000 litresis processed by centrifugation, filtra- enzyme per hour. converted Deepclean has tion, precipitation, ultrafiltrationthe risk of Conventional cleaning leaves and the like developed SKB. into ispotentially dangerous residues contaminating to result in a purified concentrated enzyme available wheat For in afood and raw materials. Then is converted to solution. This concentrate you also have with Falling range of drythe issue ofby sprayinto difficult spaces, such powder getting drying, mixed with bulk Numbers steam machinesas material to standardise the activity and free tight crevices in storage areas or complex for between 300 differentshaped equipment. provide ease of usage in flowing agents to applications, the and 350 s, Dry steam sanitises surfaces, penetrating mills. As a dry powder most enzymes are typical dosage based on manycracks, stable and can be kept for years without very crevices and other hard-to-reach areas is adjusted as years’ experi-where manual and traditional cleaning provides a losing much activity. Figure 1 methods, ence ofSKB per 500 creatingwhich mainly the production of enzymes from scheme for rely on potentially hazardous kg of flour bespoke steamchemicals,animals and microbes. plants, fail to achieve the required standards. solutions. is, This (that 1 && Grain feed millinG technoloGyGrain feed millinG technoloGy march - april 2013 | 1119 march - april 2013 |
FEATURE impacts on dough and baking properties vary widely. It is assumed that pentosans form a network with gluten; the more pentosans are involved, the firmer the network. Because they bind large amounts of water (approximately 10 times their dry weight), they reduce the availability of water for the gluten reducing its expandability. Additionally, pentosans can be cross-linked to each other by the so-called oxidative gelation, increasing their ability to bind water further. That is a main reason why darker wheat flours and mixtures containing rye flour have a lower volume yield than white flours. The volume yield of all flours can be increased considerably by adding hemicellulases. Many of these enzymes are derived from Aspergillus strains selected for or specialising in the production of hemicel- Figure 3: Action of protease on gluten lulases. Hemicellulases are often sold in com- pounds with amylase and other enzymes. Table 1: Enzymes suggested for bread and flour improvement (not exclusive) The most common hemicellulase for bak- ing applications is an endo-1, 4-ß-xylanase. Enzyme Claimed Effect It is not possible to give a general dosage recommendation as there is no stand- ard method of determining hemicellulase Alpha-amylase, bacterial Oven-rise, anti-staling, liquefaction activity. The available methods are usu- Alpha-amylase, cereal Oven-rise, anti-staling ally based on determining the release of Energy supply for yeast, dough & bread reducing sugars, the reduction of viscosity Alpha-amylase, fungal or the breakdown of synthetic or coloured structure molecules and are very difficult to relate Alpha-amylase, maltogenic, intermediate heat to each other. Moreover, even the use of Anti-staling stable a standard method for different hemicel- Ascorbic acid oxidase Protein strengthening lulases does not necessarily permit con- clusions in respect of baking properties, Beta-amylase Energy supply for yeast, browning, taste presumably because the points at which Branching enzyme (glucotransferase) Water binding hemicellulases of different origin attack the pentosan molecules are too various. Cellulase Water binding Furanosidase, arabinofuranosidase Dough structure, water binding Protease Ferulic and cumaric acid esterase Dough structure, water binding Proteases (also known as proteinases or peptidases) split the protein strands Glucoamylase, (amyloglucosidase) Energy supply, colour, flavour of the gluten molecule (Figure 3) and Glutathion oxidase Protein strengthening thus lead first to a softening and then to a complete collapse of the structure. A ß-glucanase Structure, liquefaction purified single and very specific protease Glucose oxidase, galactose oxidase, hexose would only be able to break down a few of Protein strengthening oxidase the peptide bonds, resulting in only limited softening. Hemicellulase, xylanase, pentosanase Dough structure, water binding, volume yield With short gluten structures a slight Laccase, polyphenol oxidase Dough strengthening softening may well be desirable; in this case it has a similar significance to the use Carboxyl esterase (lipase, phospholipase, Flavour, in-situ emulsification, dough stability galactolipase etc.) and volume yield, dough brightening of L-cysteine. The proteolytic action is more time-dependant than the function Lipoxygenase, lipoxidase Dough structure, decolourization of cysteine. As a result, it increases with Exo-Peptidase Colour, flavour the fermentation time of the dough. That is why there is a considerable demand for Peroxidase Protein strengthening enzyme preparations that do not contain Protease, proteinase, endo-peptidase Protein relaxation, liquefaction even traces of protease. The use of protease is less crucial with Pullulanase Structure, water binding flours that are rich in gluten. It is even very Sulfhydryl oxidase Protein strengthening common in the production of pan (toast) bread, where a soft dough that precisely Sulfhydryl transferase Protein strengthening fills the tin is required. Proteases are also Transglutaminase Protein cross-linking, gluten stabilization very useful in the production of cracker,20 | march - april 2013 Grain &feed millinG technoloGy
FEATURE such as the tyrosine groups in protein or the feruloyl residues in pentosans. The oxidative cross-linking of the pen- tosans is called oxidative gelation, a reaction resulting in increased dough firmness and dryer dough surfaces. The limiting factor in this process is the availability of oxygen because of other chemical and biochemical reaction consuming oxygen. Therefore, the conditions for oxidases are only good on the surface of the dough where plenty of oxygen is always available. This limitation can be solved by technical measures during dough preparation, for Figure 4: Reaction of glucose oxidase and some example overpressure or the supply of probable effects on dough components extra oxygen through the mixing tool. Carboxyl esterases The term carboxyl esterase comprises all lipolytic enzymes, for example (triacyl) lipase, phospholipase and galactolipase. They all catalyse the hydrolysis of acyl residues (fatty acids) from lipids. Wheat contains about 2.5-3.3 percent lipids, a typical bread flour about 2.5-2.7 percent (Chung & Ohm, 2009), but only about 1 percent are free lipids that are easily accessible by lipolytic enzymes. A schematic representation of the lipids composition of wheat flour is given in Figure 5. Lipase converts non-polar lipids Figure 5: Classification and distribution of the main lipids in wheat flour into the more polar structures diglycerides (averages; % d.s.; modif. from Pomeranz and Chung, 1978, using data from and monoglycerides, i.e. emulsifiers (Figure Chung and Ohm, 2009) 6). Lipids of wheat flour are already polar to some extent, namely phospholipids and gly- colipids are converted into more polar and biscuit or wafer flours where elasticity of is also a rich source of GOX. The enzyme hydrophilic lyso-forms by phospholipases the gluten is not desirable. stems from the pharyngeal glands of the and glycolipases. bees. However, its suitability is rather The in situ formation of mono- and dig- Glyco oxidases restricted by the taste of its carrier. lycerides from wheat lipids results in dough There are several oxidoreductases in One effect of GOX in the dough is to strengthening and larger volume yield, but nature that convert sugar molecules into oxidize glucose to form gluconic acid with according to the author’s findings doesn’t the corresponding acids, or, as in the case the aid of atmospheric oxygen, but the slight have a significant effect on starch retrograda- of sorbitol oxidase, that convert a sugar souring that occurs in the process is negligi- tion and hence bread staling. This is in con- alcohol into the corresponding sugar. The ble; its other effect is to transform water into trast to the effect of mono- and diglycerides most common oxidase (from a commercial hydrogen peroxide (Figure 4). This oxidizing which are added to a bread formula: due perspective) is glucose oxidase. Other exam- agent acts on the thiol groups of the gluten, to interaction with starch they are able to ples are maltose or galactose oxidase. More either directly or via several pathways, induc- reducing the staling rate. On the other hand, generic terms used for all these enzymes are ing formation of disulphide bonds and thus their effect on volume yield is very limited. hexose oxidase or pyranose oxidase. tightening of the protein. Since hydrogen Most probably, the action of enzymatically The enzyme glucose oxidase (GOX) is peroxide is a rather non-specific oxidizing formed emulsifiers on volume yield is pro- usually derived from the mould Aspergillus, agent, it may also react with other reducible nounced because they are already located at sometimes from Penicillium species. Honey substrates, for instance phenolic component the right sites of the dough for improving the A SOLID reputation for quality without compromise!Rota Val’s rotary and diverter valves are UK manufactured from our Wiltshire baseusing only high quality British castings.Receive 5% discount on your first order when you quote MFAPR13.For more information please visit www.rotaval.co.uk or contact ourtechnical sales team on 01249 651138 & email@example.com. Grain &feed millinG technoloGy march - april 2013 | 21
FEATURE omitted; the dough pieces will keep the shape given by the cutting; shrinkage and bending in the oven as well as the for- mation of hairline cracks (checking) are avoided. With suitable amylases, expen- sive recipe components such as milk solids otherwise necessary for sufficient browning can be omitted. Furthermore, the whole process will be less dependent on flour quality. Other flour applications Enzymes have also been introduced into flour applications others than bak- ing, for example noodles or steamed bread. For steamed bread the desired properties are similar to those in bread baking, but the technology is quite dif- Figure 6: Effect of carboxylesterases on wheat lipids ferent and requires different types of enzyme compounds. In many types of steamed bread, specific lipases are very useful, providing stability, volume and a bright crumb colour. Except for certain types of Asian noodles, for example Japanese udon noodles, a firm bite and a high cooking tolerance are advantageous. For instant noodles, the requirements are quite different, because the reduction of oil uptake during frying and a fast water uptake upon cooking are of utmost importance. Furthermore, avoiding the cracking of dried noodles is a typical aim, although this problem is caused in many cases by inadequate drying condi- Figure 7: Cross linking of protein by transglutaminase tions. Finally, the colour of the fresh or dry noodle is important. A bright colour without speckles is a desirable property of many but not all types of noodles. Allprotein properties; but for anti-staling effects, and glutamine groups to work. Although of these challenges can be approachednot enough emulsifier is formed to interfere lysine is a limited amino acid in flour, the by enzymes, namely by carboxyl este-with starch retrogradation. levels are enough for transglutaminase to rases and lipoxygenases. Nevertheless, they have a distinct work. The result is a strengthening effecteffect on the shelf life of bread because on the dough, like ascorbic acid. Referencesthey create a better ‘starting point’ at the Because it is rather expensive com- Chung, OK, Ohm, JB, 2009. Wheat Lipids. In:beginning of the storage due to improved pared to ascorbic acid, its use is limited. Wheat - Chemistry & Technology, Khan, K,volume and crumb structure. With the A special usage area can be in very Shewry, PR (ed.), AACC Press, 363-399.staling rate unchanged, this results also in long or retarded fermentation processes Pomeranz, Y and Chung, OK, 1978. Interactiona better structure (crumb softness) at the where very low amounts of the enzyme of lipids with proteins and carbohydrates inend of the storage period. will work sufficiently long. breadmaking. J. Am. Oil Chem. Soc., 285-289 . Interestingly, it is being disputed Sandstedt RM, Kneen E and Blish MJ, 1939.whether the doughs have to contain Enzymes for biscuits, crackers A standardized Wohlgemuth procedure foradditional fat, and if so, what kind of and wafers alpha-amylase activity. Cereal Chem. 16,fat, for the lipase to work satisfactorily. Whereas a high protein content and 712-723.According to our findings, fat reduces the strong gluten are desired properties inefficacy of lipase, probably by ‘distracting’ many bread processes, flours with lit-the lipase from the ‘right target’, i.e. the tle and weak gluten are preferable forflour lipids. durable baked goods. The tendency of Read the second part of this article Initially, there was also the problem dough to spring back after rolling and in the next issue of Grain and Feedof a possible impairment of taste due to the undesired formation of gluten lumps Milling Technology. Lutz Popper willthe release of flavour-active fatty acids, in wafer batter are the reasons for this discuss additives other than flour andparticularly if butter is involved. The requirement. Whether a flour with low standardisation services.most recent carboxyl esterase are more and weak protein is available or not,specific in this concern and hence do not the use of elasticity-reducing agents willaffect the flavour in most applications. have benefits in all stages of the process: The lamination will be more uniform;Transglutaminase reduction of the thickness of the dough More inforMation: This enzyme causes bond formation sheet can be performed faster and more Website: www.muehlenchemie.debetween protein folds or different pro- reproducibly; relaxing periods for thetein strands (Figure 7). It needs lysine dough sheet can be shortened or even22 | march - april 2013 Grain &feed millinG technoloGy
This digital Re-print is part of the March | April 2013 edition of Grain & Feed Milling Technology magazine. Content from the magazine is available to view free-of-charge, both as a full LINKS online magazine on our website, and as an archive of individual features on the docstoc website. Please click here to view our other publications on www.docstoc.com. March - April 2013 first published in 1891 • See the full issue In this issue: • Additives for flour standardisation Part I: Enzymes • Measures for increasing the energy • Visit the GFMT website efficiency of UFA feed mills in Switzerland • • Contact the GFMT Team Fine grinding and BS3 Xylanase • Importance improve of trace productivity in minerals weaners for nutrient stability in feed • Super • Managing mill • Subscribe to GFMT chilled maintenance grains - Maintenance options and challenges INCORPORATING PORTS, DISTRIBUTION AND FORMULATION A subscription magazine for the global flour & feed milling industries - first published in 1891 To purchase a paper copy of the magazine, or to subscribe to the paper edi- tion please contact our Circulation and Subscriptions Manager on the link adove. INFORMATION FOR ADVERTISERS - CLICK HERE Article reprints All Grain & Feed Milling Tecchnology feature articles can be re-printed as a 4 or 8 page booklets (these have been used as point of sale materials, promotional materials for shows and exhibitions etc). If you are interested in getting this article re-printed please contact the GFMT team for more informa- tion on - Tel: +44 1242 267707 - Email: firstname.lastname@example.org or visit www.gfmt.co.uk/reprints www.gfmt.co.uk