VIEWS: 0 PAGES: 8 POSTED ON: 6/10/2013
The most commonly used material to strengthen gluten is ascorbic acid, also called vitamin C. The material itself is originally a reducing rather than an oxidizing agent, but it is converted into an oxidative substance, namely dehydroxy ascorbic acid (DHAA), through the action of flour enzymes during dough preparation. DHAA basically inactivates the glutathione molecules which break down the sulfur bonds between the gluten molecules (Grosch and Wieser, 1999). With this action, dough mixing results in sulfur bonds protection without excessive breakdown, which in turn leads to dough with desired structure.
Digital Re-print - May | June 2013 Additives for flour standardisation - Part II: Additives other than enzymes Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2013 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872 www.gfmt.co.uk FEATURE Additives for flour standardisation - Part II: Additives other than enzymes by Lutz Popper, Mühlenchemie GmbH & Co. KG, Germany T he most commonly used material of 45 ppm), but the dosage tolerance is low, Cysteine to strengthen gluten is ascorbic so even a slight over dosage may result in L-cysteine, a sulfur-containing amino acid acid, also called vitamin C. The bucky doughs and rough bread surfaces. It is found in diverse proteins, breaks down the material itself is originally a reducing rather a flammable material and its usage in food- disulfide bonds between and within gluten than an oxidizing agent, but it is convert- stuff is not permitted in the EU and several molecules and becomes attached to the ed into an oxidative substance, namely other countries. bond forming regions. This prevents gluten dehydroxy ascorbic acid (DHAA), through from getting stiff, and a mobile, flexible but the action of flour enzymes during dough Others still coherent structure is secured. This effect preparation. DHAA basically inactivates Other than the ones stated above, there seems to be the opposite of ascorbic acid’s, the glutathione molecules which break are many oxidative materials and oxidation but actually they seem to complement each down the sulfur bonds between the processes utilized throughout the world. other in some processes. This synergy is gluten molecules (Grosch and Wieser, Chlorination, usage of peroxides, iodates, especially used in frozen dough processes: 1999). With this action, dough mixing persulfates, cystine and oxidative enzymes Ascorbic acid provides the necessary fer- results in sulfur bond protection without are some of these. All of these methods dif- mentation stability whereas cysteine gives excessive breakdown, which in turn leads fer by their effects on flour/dough, and their extensibility to gluten strands which have to dough with desired structure. pace of action. shorten because of freezing. Pure ascorbic acid is added to the flour in Dough relaxation, softening, Others mills at rates of typically 0.5-3 grams per 100 reduction Inactive yeast preparations are rich in kg of flour. This dosage may go up to 6-10 Dough with ‘short gluten’ (low extensibil- reducing material, but their dosage (500 – grams per 100 kg in very weak flours or for ity) is hard to process. In addition to this, gas 5,000 ppm) and price are relatively high, weakening applications like frozen dough. produced during fermentation will not be able as compared to cysteine. Levels of other Ascorbic acid is mainly produced by com- to expand the dough sufficiently and hence reducing agents like sodium metabisulfite plex biochemical processing of glucose and the volume of the end product will be small. and sulfur dioxide which are used as dough sold as powder with different granule sizes. Furthermore, for products like biscuits, crackers softening agents in biscuit and cracker pro- There are also natural sources for ascorbic and wafers, the optimum processing condi- duction are limited to 50 ppm. This amount acid, for instance acerola fruit powder, but tions can be reached when gluten structure is is not sufficient to observe a softening effect these are too expensive compared to the weaker than normal. In these situations, reduc- in strong flours. Furthermore, many coun- synthetic ones. tive materials are used to break the disulfide tries require declaration if the concentration bonds and provide gluten with more flexibility. of residual sulfur dioxide exceeds 10 ppm Potassium bromate Potassium bromate as a strong oxi- Table 1: Suggested emulsifiers with potential use in baking applications dative is still used as flour improver in Common many countries in the world. The very Emulsifier HLB Application and benefit abbreviation long lasting effect of bromate starts later than the effect of ascorbic acid and allows easier processing of the dough. Acetyl esters of monoglycerides AMG 2.5-3.5 Whipped cakes, volume Bromate creates new disulfide bonds Calcium stearoyl lactate CSL 7-9 Bread, shelf-life, volume resulting in more resistant doughs but Diacetyl tartaric esters of monoglycerides DATEM 9.2 Bread, shelf-life, volume it also oxidizes glutathione and hence Ethoxylated mono- and diglycerides High-fibre bread; shelf-life EMG 12-13 prevents gluten weakening, just like (polyglycerates) (combined with monoglycerides) ascorbic acid but without the help of Glycerol monostearate (non self-emulsifying) GMS 3.7 Shelf-life the flour’s enzymes. Glycerol monostearate (self-emulsifying) GMS 5.5 Shelf-life Usage of bromate in flour industry Lecithin LC 3-4 Shelf-life, dough properties is prohibited in the EU and many other Lactyl esters of monoglycerides LMG 3-4 Whipped cakes, volume countries because of the health con- Mono- and diglycerides MDG 2.8-3.8 Bread, cakes, cookies, volume cerns and its unstable/fire-accelerating Polyglycerol ester PGE 12-13 Whipped cakes, volume nature. Propylene glycol monostearate PGMS 1.8 Whipped cakes, co-emulsifier Azodicarbonamide Polysorbate 60 PS 60 14.4 Whipped cakes, co-emulsifier Azodicarbonamide (ADA) is utilized Succinyl monoglyceride SMG 5-7 Yeast leavened baked goods; volume in flour industry because of its oxidative Sorbitane monostearate (e.g. SPAN 60) SMS 4.7-5.9 Whipped cakes, volume action. Its dosage is similar to ascorbic Sodium stearoyl lactate SSL 18-21 Bread, shelf-life, volume acid (with a recommended maximum Sucrose esters SUE 7-13 Bread, cake, volume 12 | may - June 2013 Grain &feed millinG technoloGy FEATURE confirm this percep- less than that of its synthetic counterparts. tion. Other emulsifiers The dosage of lecithin is about 30-150 g per strongly interact with 100 kg of flour (0.03 – 0.15 %). Low dosages the starch delaying ret- increase the processing quality of the dough, rogradation and staling whereas high dosages increase dough stability and thus provide bread and fermentation tolerance, improve crumb with improved and structure and prolong shelf life. prolonged softness and freshness. Some have Mono- and diglycerides potent foaming ability These molecules are formed by breaking- because of their sur- off fatty acids from edible fats and oils. The Figure 1: Effect of reducing agents on the dough consistency face-active nature and forms that are preferred as flour improver are used as whipping are the ones that prevent staling best. This agents for sponge cake property is found in linear saturated fatty acids in the final product. Figure 1 compares the and the like. They ease the mixing of water that interact best with starch, and the most effect of cysteine and inactive yeast on the and fat and hence improve fat dispersion in effective of them all is glycerol monostearate. extensibility and resistance towards exten- bakery products that contain larger amounts of The dosage starts at 0.05 percent and may sion in a standard wheat flour dough. fat, such as biscuits, or in liquid systems such as go up to one percent, especially in high-fat wafer batters. They also decrease the amount products. Emulsifiers of necessary fat, contributing to cholesterol, Emulsifiers are polar molecules that can calorie and cost reduction. Diacetyl tartaric esters of mono- interact with many constituents of Emulsifiers and diglycerides (DATEM) that interact with gluten during mixing process Lecithin DATEMs currently are the most effective strengthen the bonds between protein chains, Lecithin is an emulsifier which has been emulsifiers for bread volume. They are various but they also provide a lubricating effect that used in bakery products for a long time. Once molecules formed by esterification of mono- allows the chains to slide over each other eas- egg yolk was used as the source of lecithin, and diglycerides (obtained from edible oils) ily. They are involved in the stabilisation of the but nowadays concentrated lecithin obtained with mono- and diacetyl tartaric acid. Some gas bubbles in dough by binding to the bound- from soy beans, canola or sunflower seeds of these molecules are more active than the ary layers. As a result, dough elasticity, oven is used. The most obvious benefit of lecithin others (Köhler, 1999), but the effect of the rise and volume increase, and the crumb pore is to lower the stickiness of the dough and mixture is better than any single type of pure size reduces. The bakers will note an increase improve its machinability. Other than this, emulsifier. in the practical water absorption, although the lecithin softens the crumb due to its interac- DATEM is rather used in bread improvers. dough rheological measurements may not tion with starch. But its effect on volume is The optimum dosage is about 400 g per 100 kg, One of these flours has the desired quality. Aqua-Inject and Farinograph®-E can tell which one. The Brabender® Aqua-Inject is the perfect ■ Automated, computer-controlled water dosing addition to the Brabender® Farinograph®-E: ■ Electronically regulated water temperature Together they determine the rheological ■ Utmost reproducible dosing and properties of dough easier, faster and more measurement accuracy accurately. ■ Work without glass burette for more safety Brabender® technology optimises the quality of your raw materials and ensures your success. Brabender® GmbH & Co. KG · www.brabender.com Aqua-Inject_210x148_GB.indd 1 29.05.2013 12:02:25 Grain &feed millinG technoloGy may - June 2013 | 13 FEATURE but much lower dosages are used actually because Bleachers The properties of gluten added from outside of the high prices. We mentioned that the effect Even though customers are getting more are different from those of native gluten. The of lipolytic enzymes is comparable to emulsifiers. and more aware of the fact that darker milled difference that can be observed by determining Recent studies are focused on producing carboxyl flours are richer in vitamin and mineral content, the water absorption and rheological properties, esteerases that may reduce DATEM usage, or bread with a crumb as white as possible is pre- resulting from partial denaturation of the protein replace it completely. ferred in many regions. Bleaching of the carote- during the drying process. Because of this, a noids which give the flour a dark colour, namely proper drying practice is the most important Sodium and calcium stearoyl lutein, can be achieved with oxidative materials. factor in preserving the function of vital gluten. lactylate (SSL and CSL) Some manufacturers do not worry about keep- These emulsifiers are formed by the Soy Flour ing the quality of the protein, because vital gluten esterification of stearic acid with lactic acid. The best-known legal material for this applica- is sometimes still considered as a byproduct of They act like DATEM, with a slightly weaker tion is enzyme-active soy flour. A clearly visible starch production. Using this low quality vital effect on dough stability and baking vol- effect can be achieved at dosages around 0.5 gluten increases the protein content of the flour, ume. On the other hand, they are more percent. There are two types of enzyme-active but does not improve the gluten properties. effective in preserving the crumb softness. soy flour in the market: deoiled and untreated. The water absorption capacity of added vital Furthermore, they are more suitable for The bleaching effect is related to the lipoxygenase gluten is lower than that of native gluten. A ratio bakery products that require a softer crust. enzyme in soybeans. Deoiled soy flour may have of 1.3-1.5 parts of water per one part of vital glu- lost some or all enzyme activity during the proc- ten can often be observed, while this ratio goes Other emulsifiers ess and hence may not be suitable for this pur- up to 2.5-3 parts of water per one part of native Other than the ones stated above, there pose, but nevertheless there are enzyme-active, gluten in flour. Also the structure of vital gluten are many more to be used in high-fiber prod- deoiled soy flours available. On the other hand, becomes shorter because of the drying process. ucts, cake bases etc. The distinctive property untreated soy flour may cause an unwanted bitter Because of this, softer wheat varieties are more among them is the HLB value (Hydophilic- taste because of the enzyme urease. suitable for producing valuable vital gluten. Lipohilic Balance). This value shows if the Because the soy flour’s bleaching effect is The colour of gluten is also an important emulsifier displays a more hydrophilic or due to an enzymatic reaction, the bleaching criterion in the market. Vital gluten mostly has a lipophilic character. Emulsifiers for high bread only starts after contact with water, that is, grayish tone that will also contribute to colour of volume yield rather have an HLB of 7 or during dough mixing. flour. This is not a desired quality though; bright higher, while emulsifiers that improve the shelf white or yellowish tones are preferred in flour life of the crumb softness exert a lower HLB, Powerful oxidatives industry. The colour is affected by the wheat probably because they have to be able to Benzoyl peroxide, potassium bromate and variety, extraction and drying methods. interfere with the non-polar interior of starch their derivatives cause bleaching because of their helices. Table 1 provides a list of common powerful oxidative effects. Added at dosages of Services emulsifiers used in baking applications. 5-10 g per 100 kg, the effect of benzoyl perox- Mühlenchemie’s mission and practical knowl- ide starts during storage of flour and the process edge lie in selecting and combining the individual Acidifiers and acidity regulators is completed in about 1-3 days. These chemicals raw materials described. The optimum composi- With germination, high amounts of amy- pose health risks by undesired residues and tion brings about synergistic effects. Since wheat lase are formed in grain. This enzyme works reaction products remaining in the final food or qualities fluctuate, Mühlenchemie helps mills to like amylase added to the flour, but has at least because of their inflammable, fire-accel- produce flours with consistent baking qualities. a stronger impact on lowering the Falling erating or even explosive nature. Furthermore, The samples of flour sent in by the mills are Number (FN). If there is too much cereal their usage in food is not permitted in the EU subjected to a rheological analysis in the compa- amylase, the baking properties are negatively and in several other countries. ny, and the results are used to develop specific affected and the FN is too low. To restore compounds for each customer. Baking trials are good baking properties, the dough may be Other agents then carried out to test the flour improvers for acidified by natural lactic acid fermentation, The colour lightening effect on crumb experi- functionality before they are offered to the mill resulting in a sour dough. This prevents the enced with the usage of ascorbic acid, emulsifiers as Alphamalt. cereal enzymes from finding the optimum and some enzymes is mostly a physical illusion. Besides customized products, Mühlenchemie conditions and hence their activity decreases. Using these improvers, one can have smaller and offers whole systems. The EMCEbest WA series But the taste and aroma developed during more evenly distributed pores which cast less increases the water absorption capacity of acidification of the dough may not be well shadow and therefore the crumb seems whiter. doughs, and thus the yield, and results in a more received by everyone. Moreover, this proc- Using lipases also may contribute to a bleaching succulent crumb and a longer shelf life. The ess takes a long time. Other than natural effect provided that there is enough of oxygen in EMCEgluten Enhancers can save on vital wheat acidification, agents that are allowed in the dough. The unsaturated fatty acids produced gluten at 1/10 of its usage level, strengthen weak foodstuff, like fruit acids, salts of these acids, by lipase are converted to hydroperoxides by the flours and make it possible to use composite carbonates and phosphates may be used. By flour’s own lipoxygenase, and these molecules in flours. careful adjustment of these, the pH range turn bleach carotenoids. Mühlenchemie offers mills further support in (acidity) of the dough may be altered to a their daily work in the form of seminars, labora- level where the enzymes cannot work opti- Vital wheat gluten tory equipment and technical training courses mally. Most preferred of these additives are Vital wheat gluten is produced by separating and helps with the quality control and improve- the ones that keep the pH value at a desired the water-insoluble proteins of wheat flour from ment of flours on the spot. level regardless of the chemical changes in the starch and soluble materials by a thorough the dough, called buffering agents. A typical washing process with water and drying of the dosage is 50-200 grams per 100 kg of flour. resulting wet gluten. The material obtained via It should be kept in mind that phosphates this process consists of around 80 percent glu- More inforMation: and carbonates add to the ash content of ten plus some remaining starch, lipids and non- Website: www.muehlenchemie.de flour. For sprout-damaged wheat, it is advisable starch carbohydrates (Pomeranz, 1988). When The first part of this article, which dis- to lower the extraction of enzyme-rich outer added to the flour, vital wheat gluten increases cusses enzymes and flour standardisa- layers of the kernels (that is, to decrease the the protein strength. This effect is easily detected tion, is in the March/April 2013 issue milling yield) and produce a whiter flour that with the help of flour analysis equipment like the of Grain and Feed Milling Technology. allows addition of ash-increasing improvers. Alveograph or the Extensograph. It is also online at www.gfmt.co.uk 14 | may - June 2013 Grain &feed millinG technoloGy This digital Re-print is part of the May | June 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. May - June 2013 first published in 1891 • See the full issue • Visit the GFMT website In this issue: • Adding value to feed milling with profit-oriented feed • Additives for flour formulation standardisation Part II: Additives other than enzymes • Contact the GFMT Team • ‘Kill step’ • High efficiency validation of elevator low-moisture buckets: extrusion modern vs traditional design • Feed focus • Pest control Poultry • Subscribe to GFMT across the supply chain • Assessing nutritional value with NIR 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: email@example.com or visit www.gfmt.co.uk/reprints www.gfmt.co.uk
Pages to are hidden for
"Additives for flour standardisation - Part II: Additives other than enzymes"Please download to view full document