Analysis of Corn Distillers Dried Grains With Solubles (DDGS) / Flour Mixtures, and Subsequent Bread Baking Trials

Transcription

1 Agriulturl nd Biosystems Engineering Pulitions Agriulturl nd Biosystems Engineering Anlysis of Corn Distillers Dried Grins With Solules (DDGS) / Mixtures, nd Susequent Bred Bking Trils J. A. Sunders South Dkot Stte University Kurt A. Rosentrter Iow Stte University, krosent@istte.edu P. G. Krishnn South Dkot Stte University Follow this nd dditionl works t: Prt of the Agriulture Commons, nd the Bioresoure nd Agriulturl Engineering Commons The omplete iliogrphi informtion for this item n e found t e_eng_pus/513. For informtion on how to ite this item, plese visit howtoite.html. This Artile is rought to you for free nd open ess y the Agriulturl nd Biosystems Engineering t Iow Stte University Digitl Repository. It hs een epted for inlusion in Agriulturl nd Biosystems Engineering Pulitions y n uthorized dministrtor of Iow Stte University Digitl Repository. For more informtion, plese ontt digirep@istte.edu.

2 Anlysis of Corn Distillers Dried Grins With Solules (DDGS) / Mixtures, nd Susequent Bred Bking Trils Astrt Grins offer vriety of nutrients; it is thought tht through the ddition of distillers dried grins with solules (DDGS) the fier nd protein in ked produts my e improved. In this study, ll-purpose flour nd red flour were tested with vrious DDGS sustitution levels (%, 25%, or 5% flour sustitution) with the dough onditioner sodium steroyl ltylte (SSL) (%,.15%, or.3% flour weight sis). SSL is surftnt produed from reting steri id with food grde lti id in the presene of sodium. Overll, s the sustitution level of DDGS inresed, so did protein, moisture, sh, nd Hunter- vlues. Pek height, side height, width, nd length of ked loves deresed s DDGS quntity inresed, however. Bked red ontining SSL hd enhned qulity, with inresing dough strength, rte of hydrtion, mixing tolerne, rum strength, lof volume, nd shelf life. Overll, 25-5% DDGS sustitution ppered to hve negtive effet on physil fetures despite the ft tht the nutrient ontent ws enhned. Less thn 25% DDGS hd miniml negtive effets on red properties. Keywords Bred, Bking, Ingredient, Protein, Fier Disiplines Agriulture Bioresoure nd Agriulturl Engineering Comments This rtile is from Journl of Food Reserh 3 (214): 78 14, doi:1.5539/jfr.v3n3p78. Cretive Commons Liense This work is liensed under Cretive Commons Attriution 3. Liense. This rtile is ville t Iow Stte University Digitl Repository:

3 Journl of Food Reserh; Vol. 3, No. 3; 214 ISSN E-ISSN Pulished y Cndin Center of Siene nd Edution Anlysis of Corn Distillers Dried Grins With Solules (DDGS) / Mixtures, nd Susequent Bred Bking Trils J. A. Sunders 1, Kurt A. Rosentrter 2 & P. G. Krishnn 1 1 Deprtment of Nutrition, Food Siene, nd Hospitlity, South Dkot Stte University, USA 2 Deprtment of Agriulturl nd Biosystems Engineering, Iow Stte University, Ames, IA, USA Correspondene: Kurt A. Rosentrter, Deprtment of Agriulturl nd Biosystems Engineering, Iow Stte University, 3167 NSRIC Building, Ames, IA, 511, USA. E-mil: krosent@istte.edu Reeived: August 14, 213 Aepted: Mrh 23, 214 Online Pulished: My 6, 214 doi:1.5539/jfr.v3n3p78 URL: Astrt Grins offer vriety of nutrients; it is thought tht through the ddition of distillers dried grins with solules (DDGS) the fier nd protein in ked produts my e improved. In this study, ll-purpose flour nd red flour were tested with vrious DDGS sustitution levels (%, 25%, or 5% flour sustitution) with the dough onditioner sodium steroyl ltylte (SSL) (%,.15%, or.3% flour weight sis). SSL is surftnt produed from reting steri id with food grde lti id in the presene of sodium. Overll, s the sustitution level of DDGS inresed, so did protein, moisture, sh, nd Hunter- vlues. Pek height, side height, width, nd length of ked loves deresed s DDGS quntity inresed, however. Bked red ontining SSL hd enhned qulity, with inresing dough strength, rte of hydrtion, mixing tolerne, rum strength, lof volume, nd shelf life. Overll, 25-5% DDGS sustitution ppered to hve negtive effet on physil fetures despite the ft tht the nutrient ontent ws enhned. Less thn 25% DDGS hd miniml negtive effets on red properties. Keywords: red, king, ingredient, protein, fier 1. Introdution Grins suh s whet, orn, rie, nd ots hve trditionlly een mjor onstituents in the humn diet. Historilly this hs een due to intrinsi nutrients s well s funtionlity. Whet is very verstile, s it forms omplex known s gluten, whih ontins 8% - 9% glutenin nd glidin proteins (Lillird, 2; Wng et l., 24). Mny ftors impt gluten struture nd funtion in food systems. Gluten proteins must e hydrted nd then physilly mnipulted to form oth the gluten omplex nd ultimtely the strh-protein mtrix. Gluten offers struture to ked produts, suh s reds, y trpping fermenttion gses thus llowing dough to rise. Wek gluten struture n result in exessive expnsion nd uneven texture, wheres too strong gluten struture results in deresed expnsion nd low lof volume (Shofield & Booth, 1983). Ultimtely, protein ontent nd qulity impt red qulity nd struture. Not only does the preprtion proess ffet the finl produt, ut ingredients used nd flour qulity lso hve effets. To overome potentil vritions nd improve qulity, vriety of dough onditioners, hydroolloids, nd enzyme tretments re often used in produts to overome differenes nd defiienies in flour qulities (Azizi & Ro, 24). These dditives hve mrosopi effet on dough y induing struturl hnges to the flour (Rosell et l., 27). Hydroolloids re wter-solule polyshrides tht provide vrious funtionl properties, inluding gelling, thikening, emulsifying, stilizing, nd foming; they n lso e used for syneresis inhiition, wter retention, nd improving texturl properties. Gur gum is known for enhning red lof volume nd texture (Riott et l., 24). Hydroxypropylmethylellulose (HPMC) retes softer red rum, inresed lof volume, enhned shelf life, nd improved sensory hrteristis (Brens & Rosell, 25; Collr et l., 1998; Rosell et l., 21). Other exmples inlude K-rrgeenn, sodium lginte, nd xnthn gum, ll of whih hve een found to retrd rum hrdening of red (Gurd et l., 24). Biohemil mehnisms llow enzymes to fvor ovlent onding of proteins, thus improving funtionl properties of reds (Cllero et l., 26). A dough onditioner ommonly used in industry is sodium steroyl ltylte (SSL). SSL is surftnt tht is produed y reting steri id (5-9%) with food grde lti id in the presene of sodium (Krog & Luridsen, 1976). Surftnts inrese the qulity of ked red y 78

4 inresing dough strength, inresing rte of hydrtion, mixing tolerne, rum strength, sliing ehvior, lof volume, shelf stility, nd reduing shortening requirements (Azizi & Ro, 24). The USDA hs pproved the use of SSL t.5% (w/w) of flour weight in red (CFR, 1986). Sine flour qulity vritions gretly ffet end produts, it is importnt to nlyze flour properties efore use. This nlysis n e ompleted using vrious proesses, equipment, nd systems. Alveogrph tests determine prmeters suh s tenity (P, or resistne to extension), dough extensiility (L), deformtion energy (W), urve onfigurtion rtio (P/L), nd proteolyti degrdtion. Consistogrph tests quntify the ehvior of the flour during mixing. Prmeters olleted n inlude wter sorption, dough development time, tolerne, nd dey vlues (onsisteny differene etween height t pek nd its vlue t speified level) (Cllero et l., 26). Dough n lso e nlyzed with vriety of instruments nd proedures. Extensigrph tests determine dough s resistne to eing extended, whih n impt gs retention during fermenttion nd oven rise. Fermentogrph quntifies dough ehvior during expnsion of gs ells (Hrušková et l., 26). Mixol nlyzes mixing nd psting properties of flours. The dough is mixed under ontrolled tempertures until temperture of 9 C is rehed; this is followed y ooling step. Torque (expressed in N-m) is mesured in rel time s it is produed etween the dough nd kneding rms (Rosell et l., 27). Another ommonly-used test is rpid viso-nlysis (Rpid Viso Anlyzer) (Shittu et l., 27; Soulk & Morrison 1985). During testing, it is lso importnt to use onsistent lof preprtion method. B. Hnsen nd A. Hnsen (1992) onluded tht the use of king mhines in sientifi lortories ould result in high repetility nd reproduiility. Although these systems work well, they n e rther fixed nd nnot sustitute for ker who n use vrious king proedures. Test king is highly-dependent upon the ker s ompetene nd experiene. Bking mhines remove inonsistenies tht n e found in mnul methods. Advntges inlude rpid nd esy implementtion, low pitl expense, nd onsistent mixing nd king. Bred king trils n thus e ompleted using onsistent formul nd proedure. One red loves re mde, qulity nlyses n e ompleted y exmining lof weight, lof volume, speifi volume, nd lof height/width rtio of the entrl slie (Cllero et l., 26; Shittu et l., 27; Soulk & Morrison, 1985). A texture nlyzer n e used to quntify hrteristis suh s ompression, penetrtion, three-point ending, nd fore-displement. Other ommon tests for ked red inlude rum firmness, olor indies (olorimeter), rum moisture, rum hrdness (penetrometer), density, porosity, nd softness (AACC, 2). These tests give reserhers quntifile methods to quntify properties suh s rispy, rky, nd hrd (Pmies et l., 2). The forementioned methods re essentil for ssessing the effetiveness of new ingredients. For exmple, distillers dried grins with solules (DDGS) is n ingredient whih n provide sustntil protein nd fier to ked produts, ut to dte hs seen limited use in foods. DDGS is erel-sed ingredient high in fier ut sent of gluten-forming proteins. Over the lst few dedes, mny studies hve een ompleted whih hve exmined flour replement with DDGS for vriety of food produts. Tsen et l. (1982) used orn DDGS t 15% in molsses nd spie ookies, nd t 25% in hoolte hip ookies. Rso et l. (1987) used whet DDGS t 3% in hoolte hip ookies nd nn red. Aot et l. (1991) used 36% untreted DDGS in otmel muffins. Reddy et l. (1986) used distillers dried grins (DDG) t 1% in whet muffins nd 15% in muffins tht hd lueerries or risins dded; DDG improved physil hrteristis nd inresed onsumer eptne. Brohetti et l. (1991) used 5-1% DDG in red, whih resulted in eptle sensory ttriutes; they lso inorported up to 15% DDG in red, whih ws lso eptle, with the exeption of differenes in pperne ompred to the ontrol. Brewers grins, similr to DDGS nd DDG, hve een suessfully sustituted t 6% (Finley & Hnmoto, 198) nd 1% (Tsen et l., 1982) into reds. Depending on DDGS sustitution levels, red fermenttion my e hindered due to dilution of gluten, thus ltering the qulity of finl produts. A study ompleted y Amodt et l. (25) whih investigted red hrteristis s funtion of protein qulity indited tht flour lends with strengthened protein qulity resulted in red loves with lrger lof volume nd red slie re, nd formed higher height to width rtio. Rso et l. (199) hypothesized tht whet DDGS my hve redued negtive effet on gluten formtion ompred to other high-fier ingredients. Whet DDGS my hve enhned eletrostti intertions during protein hydrtion, whih ould improve gluten funtionlity. Additionlly, high temperture post-fermenttion tretments my soften the fier in the DDGS, llowing fster hydrtion, whih my derese its inlintion to punture developing ir ells. Mnufturing proesses lso ffet funtionlity of DDGS. Rso et l. (1987) investigted drying systems nd 79

5 found tht DDGS produed using hrsh het tretments were less suitle for kery produts thn DDGS produed using drum dryers t lower tempertures. Food mtries using the hrsh drying were of signifint poorer qulity. Tempertures during therml proesses suh s extrusion (1-19 C), flking (3-15 C), isuit or rker proessing (1-14 C), nd ommeril king (19-26 C) ffet the resulting physil nd funtionl properties (Hnsen et l., 1975; Donovn, 1977; Li & Lee, 1996). Hydrtion levels nd proessing tempertures n determine whether gluten or strh will ontriute to red struture or hinder it. High moisture systems (45-5%) re ommonly used for produts suh s reds, noodles, pst, nd isuits, nd they utilize gluten to provide the mjority of the struture (MRithie, 1992). Low moisture systems (< 35%), often used for extruded produts, generlly depend on strh for struture (Chnvrier et l., 26). In reent yers, the ethnol industry hs evolved, nd most DDGS is now produed from orn using the dry grind mnufturing proess. But, very little reserh hs exmined use of this ingredient in humn foods. And no studies hve yet een onduted to improve DDGS funtionlity using dough onditioners. Perhps these n improve DDGS use in red systems. Therefore, the ojetives of this study were to 1) exmine the effets of orn-sed DDGS on funtionlity of whet flour/ddgs lends, 2) exmine the impts of whet flour/ddgs lends on red properties, nd 3) determine if SSL n improve DDGS funtionlity nd improve reds mde with this ingredient. 2. Mterils nd Methods 2.1 Mixtures DDGS for this experiment ws quired from ommeril fuel ethnol plnt nd ws milled in Glen Mills In. (Clifton, NJ, USA) mill, providing men prtile dimeter size of.384 mm. Using ftoril experimentl design (Tle 1), ll-purpose flour nd red flour were tested with vrious DDGS sustitution levels (, 25, or 5% flour sustitution) nd vrious levels of the dough onditioner sodium steroyl ltylte (SSL) (,.15, or.3% flour weight sis). Independent vriles were DDGS replement (3 levels), SSL inlusion (3 levels), nd type of flour (ll-purpose vs. red). Dependent vriles inluded protein (% d, dry sis) using AACC method 46-3 (2), lipid (% d) using method (AOAC, 23), sh (% d) using method 8-3 (AACC, 2), nd moisture (% w, wet sis) using method (AACC, 2). All flours were quired from lol groery store. Mixtures of the vrious tretment omintions were stored t 2.5 ± C until use. Tle 1. Experimentl design for flour mixtures used in the study 1 Tretment DDGS Su. Levels (%) SSL (%) 1 AP 2 AP.3 3 AP 5 4 AP B 6 B.3 7 B 5 8 B AP B AP indites ll-purpose flour; B indites red flour; this design ws ftoril with 2 enter points (tretments 9 nd 1), thus 1 totl tretment omintions. Eh tretment ws prepred in duplite. 2.2 Mixol Anlysis A Mixol mhine (Tripette & Renud Chopin, Villeneuve L Grenne edex, Frne) ws used to exmine the dough ehvior of the flour lends. Mnufturer s instrutions were followed in order to omplete the Chopin Mixol dough rheology tests (Anonymous, 25). Wter sorption levels, dough mixing time, dough stility, nd mixing tolerne of the flour mixtures were determined from the Mixol urves s funtion of mixing nd time. The torque (expressed in Nm) of the dough kneded etween two mixing ldes ws mesured in rel time. 8

6 Physil prmeters of the flour were nlyzed using the following Mixol properties: mplitude (Nm), stility (s), wter sorption, α (Nm/min), β (Nm/min), nd γ (Nm/min). The Chopin+ protool s totl nlysis time ws 45 minutes nd it utilized n 8-rpm mixing speed, 1.1 Nm trget torque (for C1), 3 C tnk temperture, nd 75 g dough weight. 2.3 Bking Trils Two red mhines (OSTER 2 l. EXPRESSBAKE, Sunem Corportion, 1999) were used for the red king experiment to redue king differenes nd derese error. The mhines hd the verstility of 1.5 l or 2 l loves, 18 red settings, 3 rust olor seletions, dely ker timer, ool touh exterior nd Express Bke yle options (6 min). The king pn ws non-stik, ovl luminum red pn with the following dimensions: 18 m length, 13.6 m width, nd 13.2 m height. A hook tthed to the ottom mixed nd kneded the dough. Ten flour mixtures were ked (replited twie), for totl of 2 loves of red. For this experiment, the mhines were djusted to the Bsi red mking setting (1.5 l lof), with medium rust olor, whih llowed the reds to e ked in 3 hours. The following formultion ws used to produe eh 1.5 l lof: 24 g old wter (17 C), 2 g vegetle (soyen) oil, 3 g sugr, 1 g slt, 4 g flour mixture, nd 8 g quik ting dried yest. Liquid ingredients were dded first, dry ingredients seond, nd yest lst. Bred mhine stges were s follows: 1 min dough ws first kneded, 2 min dough egins to rise, 15 min dough ws kneded seond time, 2 min dough ontinues to rise, 3 se dough ws punhed down, 55 min dough rises finl time, 6 min red kes (Sunem Corportion, 1999). During the proess, the red loves with 25% or 5% DDGS replements were losely monitored to ensure the doughs formed pproprite lls. Proximte omposition of the ked reds inluded protein (%d) using method 46-3 (AACC, 2), sh (%d) using method 8-3 (AACC, 2), nd lipid (%d) using method (AOAC, 23). Physil properties of the red inluded side height (height of sides of loves until the top strts to mound, m), pek height (height of loves to the top of the mound (i.e. t enter), m), width (m), length (m), mss (g). Moisture (%w) ws determined using method (AACC, 2). Wter tivity ws determined using wter tivity meter (AW Sprint). Strength (MP) nd stiffness (MP) were determined using n Instron testing mhine. Hunter L,, nd vlues, for oth internl rum nd exterior rust olor, were mesured with Hunter spetroolorimeter (LSn XE, Hunter Assoites, Reston, VA, USA). Method 1-9 (AACC, 2) ws used to sujetively exmine red qulity, nd inluded uniformity, size, thikness of ell wlls, grin, moistness, tenderness, softness, nd rum olor. 2.4 Sttistil Anlysis The ompletely rndomized, ftoril experimentl design ws with dditionl 2 enter points for totl of 1 tretment omintions replited three times to totl 3 runs (Tle 1). Sttistil nlyses on ll olleted dt were performed vi SAS v.8. (SAS Institute, Cry, NC) nd Mirosoft Exel v.23 (Mirosoft Corp., Redmond, WA) softwre, using Type I error rte (α) of.5, nd inluded summry sttistis, generl liner models to test for differenes etween experimentl tretments (i.e., min, intertion, nd tretment effets), nd liner orreltions. 3. Results nd Disussion 3.1 Mixtures Chemil Properties Tle 2 shows the min effets on proximte omposition of ll ten flour mixtures. The quntity of DDGS replement resulted in signifint differenes in protein, lipid, sh nd moisture. The perentge of sodium steryl ltylte (SSL) inluded resulted in signifint differenes for protein, lipid, nd moisture. Finlly, the type of flour used resulted in signifint differenes in protein, sh, nd moisture. Tretment omintion effets were signifint s well (Figure 1). 81

7 A B Ash (% d) DDGS e f d Moisture Content (% w) DDGS C D Moisture Content (% w) Protein (% d) e f d SSL.15.3 DDGS 25 5 E Protein (% d) SSL DDGS 25 5 Figure 1. Tretment omintion effets on sh, moisture, nd protein due to flour type (1 is ll-purpose flour, 2 is red flour), dough onditioner levels, nd DDGS levels. (A); etween moisture ontent, flour, nd DDGS levels (B); etween moisture ontent, flour, nd SSL levels (C); etween protein, flour, nd DDGS levels (D); nd etween protein, SSL, nd DDGS levels (E). Overll, s DDGS levels inrese the quntity of protein nd sh inrese while moisture levels derese. Error rs represent ± 1 stndrd devition 82

8 Tle 2. Min effets for proximte omposition of flour mixtures 1 Protein (% d) Lipid (% d) Ash (% d) Moisture (% w) Men St. Dev. Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. There ws sttistilly signifint inresing trend in sh ontent s the perentge of DDGS sustitution inresed. Tsen et l. (1983) lso found tht the ddition of DDG into flour formultions inresed sh ontent ompred to white flour. Ash ontent is hevily impted y environmentl ftors suh s the fertility of the soil nd genetis of the plnt (Fennem, 1996). Other onstituents my inlude quntity of sunlight reeived, ess to wter, nd stge of growth during hrvest. mixtures tht hd % DDGS hd men sh ontent of.66%, 25% DDGS men sh ontent of 1.63%, nd 5% DDGS hd men sh ontent of 2.54%. This ws resonle, s the ddition of DDGS, firous mteril, to flour resulted in more nutritive nd non-nutritive residues left fter shing. As the quntity of DDGS inresed, moisture levels deresed. In ft, the initil moisture ontent of DDGS (12.9%) hd higher perentge of wter ompred to the ll-purpose (7.9%) or red flours (7.7%). Therefore, it my e logil to ssume tht s the perentge of DDGS (whih ontined greter initil moisture), repled more ll-purpose or red flour (whih were drier thn the DDGS), the flour mixture moisture ontent would inrese. DDGS lso ontins high level of fier, whih n redily sor free wter. Dreese nd Hoseney (1982) onluded tht produts high in fier lso hd inresed quntity of wter sorption. Therefore, in order to hieve n idel produt, the quntity of liquid inluded in the formultion my need to e inresed. One the fier moleules re softened, the fier should inorporte more esily into the dough system. Fier plys mny roles in food systems, suh s providing struture nd ulk, modifition of rheologil properties, s well s other funtions (Fennem, 1996). Severl studies hve dvoted the ide tht DDGS would provide n exellent fier supplement for ked produts (Brohetti et l., 1991; Welti & Eeling, 1982; Wu et l., 1984; Rso et l., 1987). The quntity of moisture slightly inresed s the SSL in red flour mixtures inresed. SSL is food dditive, whih is tegorized s surftnt. It is mphiphili, nd exhiits oth hydrophili nd hydrophoi properties. Its mjor funtion is to redue interfil tension etween two fluids. Other funtionl properties of surftnts inlude emulsifying, foming, soluilizing, wetting, nd dispersing (Lillird, 2). The kery industry uses surftnts to improve dough-mixing qulities nd to enhne lof volume. Azizi nd Ro (24) ompleted study tht nlyzed the omintion of surftnt gels nd gums on dough nd red systems. Frinogrph results reveled tht surftnt gels tully derese flours ility to sor wter y.4-1.2%. Also, lveogrph hrteristis showed ml inrese in the swelling index of dough s using surftnts. Less vrition in moisture ontent ws shown y ll-purpose flour mixtures nd likely due to derese in wter sorption. Moisture ontent inresed with inresed SSL levels. The red flours slightly inresed swelling ility my explin this slight inrese in moisture ontent. Perhps dditionl wter ws ptured into the food mtrix nd ws not le to e dissipted s stem during king. For the most prt, the funtion of the surftnts is to redue interfil tension in food systems, deresing the mount of wter tht flour n sor. The protein 83

9 Journl of Food Reserh Vol. 3, No. 3; 214 ontent inresed s the quntity of DDGS inluded inresed. Reddy et l. (1986) oserved n inrese in mino id ontent of muffins ontining DDGS. When 1, 15, or 2% of DDGS ws ddedd to the muffins the following mino id ontents gretly inresed: threonine, serine, glutmi id, lnine, methionine, leuine, nd histidine. Of these, threonine, methionine, leuine, nd histidine re essentil mino ids, whih nnot e mde in the ody nd must e otined through the diet (Wrdlw & Kessel, 22). The ddition of proteins to food system offers dditionl funtionlity suh s dispersiility, swelling, wter-holding pity, geltion, nd visosity (Fennem, 1996). DDGS ontins firly high mount of protein; therefore, higher perentges of replement should result in inresed protein quntities. Similrly, protein ontent inresed s the quntity of SSL inresed. Perhps SSL lters the mehnism in whih moleules intert, nd the proess y whih hemil or physil retions our. For exmple, mye the redued interfil surfe tension llowed more proteins to dsor or ondense onto the surfe of the flour (Fennem, 1996) Mixol The Mixol instrumentt hs pilities to mesuree physil properties of dough suh s stility, strength, nd psting. In this study, dough ws sujeted to dul mixing of two kneding rms with n pplied temperture onstrint. All torque mesurements were ompleted in rel time (Khrmn et l., 28). The Mixol urve is typilly divided into five min prmeters (Figure 2): development (C1), protein redution (C2), strh geltiniztion (C3), mylse tivity (C4), nd strh gelling (C5). Figure 2. Typil outputt produed when running Mixol test (for Tretment 1). The primry output inludes temperture urves for the owl nd the dough, s well s reporting torque exerted on the rotry lde in the instrument. The min phses of the resulting Mixol torque urve re denoted on 1 through 5 Development, stge C1, ours when mximum torque is rehed or time elpsed during heting results in torque remining t 1.1 N-m (Collr et l., 27). wter sorption pities re determined while t onstnt temperture. Properties suh s stility, elstiity, nd wter sorption re lso mesured. Torque inreses until mximum vlue is rehed, whih indites thtt the dough is ple of resisting deformtion for period of time (Khrmn et l., 28). Mixing onditions tht re exessive n use dough properties to hnge from smooth nd elsti to slk nd stiky (Rosell et l., 27). In stge C2, protein redution ours nd the minimum torque produed is sujeted to mehnil stresss nd therml onstrints (Collr et l., 27). Protein wekening ours when the dough is over-mnipulted. Depending on flour omposition, lower protein qulities re signified y greter dereses in onsisteny. Another derese in onsisteny n e viewed on the Mixol urve, in setion C2, when tempertures egin to inrese. After the initil derese from rising tempertures, dough onsisteny will then egin to inrese 84

10 (Khrmn et l., 28). However, this eventul inrese in onsisteny is mostly ontriuted to the eginning of stge C3, strh geltiniztion. The qulity of strh determines the rise in onsisteny. Strh grnules sor wter nd swell, while visosity inreses due to lehing of mylose (Khrmn et l., 28). Strh geltiniztion results in pek torque during the heting stges, omprising initil nd finl psting (Collr et l., 27). Geltiniztion ours when mylose nd/or mylopetin (insolule in old wter) moleules re suspended in wter, produing strh slurry. One heting egins, wter eomes sored nd grnules hydrte. Continued heting wekens hydrogen onds s moleules swell resulting in irreversile hnges to the strh struture nd eventully some grnules will urst (White & Johnson, 23). In stge C4, endogenous or mylsti tivity results in minimum torque during the ooling stge when rehing stility (Collr et l., 27). This tivity ultimtely determines how lrge the derese in onsisteny will e. Lrger dereses re proportionl to greter quntity of mylsti tivity (Anonymous, 25; Khrmn et l., 28). Two types of mylses inlude α-mylse nd β-mylse. Alph mylse hydrolyzes interior α-1,4-gluosidi onds of strh, glyogen, nd ylodextrins. These enzymes re endo-splitting whih ts to inrese visosity. Bet-mylse hydrolyze the α-1,4-gluosidi onds of strh eginning t the non-reduing end to result in β-mltose. Sine they re exo-splitting, mny onds need to e hydrolyzed efore signifint impt on visosity n e seen (Fennem, 1996). Finlly, stge C5, gel formtion, whih is relted to retrogrdtion, uses n inrese in onsisteny mong the dough s the temperture dereses for the ooling stge (Khrmn et l., 28). This ooling stge llows the strh to retret nd thus inrese produt onsisteny. Stling my e delyed through the ddition of ertin hemils tht enhne produt flexiility (Anonymous, 25). Retrogrdtion ours fter mximum visosity is rehed, in whih some grnules hve roken or urst. Upon ooling of the strh solution, some strh grnules will prtilly ressoite to form gel. The retrogrdtion of mylopetin requires more time thn mylose, giving it the distintion for using prt of stling (Fennem, 1996). The Mixol ollets dditionl properties, omprle to the Frinogrph (Brender Instruments, New Jersey). A Frinogrph mesures flour nd dough indies from the first 8 min of smple run, wheres the Mixol further nlyzes flour s performne throughout the entire red mking proess, inluding the heting nd ooling phses. These extr phses hve the potentil to tie reserh nd industry together, s the urve n relte differenes etween flours nd trditionl industril king onditions. The Mixol instrument ids in explining king performne differenes due to strh-protein intertions, enzyme tivity, geltiniztion, gelling of strh, nd environmentl ftors (Sunders et l., 27). A study ompleted y Khrmn et l. (28) tested the possiility of using the Mixol versus Zeleny sedimenttion or Alveoonsistogrph vlues to predit ke-king qulity of vrious flours. Results showed tht Mixol nlysis proved to e useful tool wheres the Alveoonsistogrph results nd ke hrteristis were not signifint. Overll, the Mixol tehnique hs een viewed s omprle to lssil instruments suh s the Frinogrph, Mixogrph, Extensogrph, or Alveogrph (Bloskm & Bushuk, 1988; Chiotelli et l., 24). Tle 3 illustrtes the min effets for the Mixol nlysis of the flour mixtures. The perentge of DDGS sustitution resulted in signifint differenes mong mplitude, stility, wter sorption, protein rekdown (α), nd ooking stility rte (γ). The perentge of SSL resulted in signifint differenes mong wter sorption, α, nd geltiniztion (β). Finlly, the type of flour inluded in the flour mixtures resulted in signifint differenes mong stility, wter sorption nd γ. Tretment omintions were lso signifint (Figure 3). As the perentge of DDGS inresed, the stility of the dough deresed. Sine DDGS mteril ontins no gluten forming proteins, it mkes sense tht the dough system would hve less stility. A slight inresing trend showed tht s the quntity of DDGS inresed, wter sorption lso inresed. An inresed mount of wter ws sored due to the inresed levels of fier provided from the DDGS. Fier required dditionl wter in order to soften nd to e inorported into dough ll. Also, s the quntity of DDGS inresed, so did γ vlues, exept for the.15% whose vlues were not ville through dt nlysis. γ vlues re inditive of the rte in whih dough system rehes ooking stility. As DDGS inresed, it took less time to stilize the ooking proess, whih used γ rte vlues to inrese. This might influene the eptne of DDGS in industry, s less time is required to reh stility Collr et l. (27) defined α, β nd γ on Mixol urve s sending nd desending urves to e protein rekdown, geltiniztion, nd ooking stility rte, respetively. Tle 3 illustrtes these vlues found in the tretments, nd Figure 4 shows respetive Mixol urves. The owl temperture ws greter thn dough temperture euse heting element ws pplied to the mixing owl, whih simultes the king proess, thus 85

11 the owl temperture ws lwys higher thn the dough temperture. α vlues tht re higher re inditive of protein rekdown, or wekening of the flour mixture. C2 urves tht derese less ould e good inditors of protein qulity. As the quntity of DDGS inresed, the slope t whih protein rekdown ourred lso inresed y the α vlues eoming more negtive. Even though gluten forming proteins deresed s DDGS inresed, the DDGS signifintly dds other proteins to the flour mixture, thus there is more protein in the system to potentilly rekdown. The red flour mixtures hd higher initil protein ontent thn the ll-purpose mixtures, thus showing slightly inresed protein wekening. Bred flour urves demonstrte slightly lower deresed slope nd urve thn ll-purpose flour. A B Stility (s) Gmm (N-m/min) DDGS DDGS C Wter Asorption (%) SSL d d DDG 25 5 Figure 3. Tretment omintion effets on stility, gmm, nd wter sorption etween due to flour (1=ll-purpose & 2=red) nd DDGS levels (A); etween γ, flour, nd DDGS levels (B); etween wter sorption, SSL, nd DDGS levels (C). γ vlues were not produed for the enter points (25% DDGS) during the Mixol nlysis. Overll, s the quntity of DDGS inreses wter sorption nd γ vlues inrese while time to reh stility dereses. Error rs represent ± 1 stndrd devition 86

12 Tle 3. Min effets for Mixol opertionl prmeters 1 Amplitude (Nm) Stility (s) Wter Asorption (%) Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred α (N-m/min) β (N-m/min) γ (N-m/min) Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) N/A N/A SSL (%) N/A N/A All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. 87

13 A B C D E F G H I J Figure 4. Mixol urves for tretments 1-1. A) 1% ll-purpose flour (Trt. 1); B) All-purpose flour nd.3% SSL (Trt. 2); C) All-purpose flour nd 5% DDGS (Trt. 3); D) All-purpose flour, 5% DDGS, nd.3% SSL (Trt. 4); E) 1% red flour (Trt. 5); F) Bred flour nd.3% SSL (Trt. 6); G) Bred flour nd 5% DDGS (Trt. 7); H) Bred flour, 5% DDGS, nd.3% SSL (Trt. 8); I) All-purpose flour, 25% DDGS, nd.15% SSL (Trt. 9); J) Bred flour, 25% DDGS, nd.15% SSL (Trt. 1) 88

14 Positive β vlues re good inditors of strh geltiniztion. However, if the β vlues eome too high it is possile tht the strh slurry my eome over-geltinized. Overooked strh grnules tend to swell nd urst resulting in omplete loss of rystllinity nd irefringene. Suh strh moleules re inresingly suseptile to hydrolysis vi enzymes (Nielsen, 23). On the other hnd, lower β vlues indite little to no strh geltiniztion or slower rte. This would then indite tht the flour does not ontin enough reduing sugrs. Not ll flour mixtures will omplete suffiient strh geltiniztion to eome visous. Even though they my not e used in some ked produts, industry n find other uses for thin strh slurries (e.g., in pie fillings). Figure 4 shows tht s the perentge of DDGS inresed, the quntity of strh geltiniztion deresed. DDGS is low in sugr nd strh, s these were used for ethnol prodution. DDGS is low in reduing sugrs neessry for strh geltiniztion. γ vlues indite the slope nd the rte tht ooking stility is rehed. As the quntity of DDGS inresed, γ vlues deresed, inditing less time needed to reh ooking stility. This my e n industril dvntge, in tht less time needed to reh ooking stility ould e fvorle in kery setting. 3.2 Bking Anlysis Chemil Properties Tle 4 showed the min effets of the independent vriles on the proximte omposition of the red loves. As the perentge of DDGS replement inresed, signifint differenes were found mong protein, sh, nd lipid vlues. A signifint differene ws lso found etween type of flour nd protein. As DDGS sustitution inresed, so did protein ontent. This reffirms the study ompleted y Reddy et l. (1986), whih showed n inrese in protein ontent of muffins s DDGS sustitution inresed. The ddition of proteins my hve strengthened the food system y offering extr proteins to promote funtionl tsks suh dispersiility, swelling, wter-holding pity, geltion, nd visosity (Fennem, 1996) Physil Properties Tle 5 shows the min effets of the independent vriles on the physil properties of the red loves. As the quntity of DDGS inresed, signifint differenes ould e found in strength, wter tivity, -rust, -rust, L-rum, -rum, -rum, side height, pek height, width, length, nd mss. As the perentge of SSL inresed, signifint intertions etween strength, -rust, L-rum, -rum, pek height, width, nd mss were found. Finlly, the type of flour showed signifint differenes mong strength, wter tivity, -rum, side height, pek height, nd length. Tretment omintion effets were lso signifint (Figure 5). Hunter rust vlues deresed s the quntity of DDGS nd SSL inresed. As the quntity of red pigments derese, the produt eomes more rown. As the level of DDGS inreses, it ppers tht the Millrd retions nd rmeliztion during king re ftors tht my ontriute to rowning. Hunter vlues deresed s did Hunter L vlues for the rust olor, lso inditing the presene of Millrd rowning. SSL my lso ontriute to the derese in Hunter vlues s the dough onditioner my lter the wy moleules intert during king. Hunter rum vlues signifintly inresed from % to 25% DDGS, whih indited more red pigments. All in ll, DDGS hs more initil red pigments thn found in ll-purpose or red flour. Therefore, s the level of DDGS inresed, the Hunter vlue of the interior rum should eome redder s well. These vlues did not derese s the Hunter rust vlues do, euse the interior rum ws proteted nd enountered deresed mount of Millrd rowning ompred to the rust. Rso et l. (199) determined how the ddition of vriety of distillers grin produts from whet nd rley would ffet mixing nd king properties of reds nd ookies. Breds inluded 4 or 8% of vrious types of distillers grins, while the ookies sustituted 2, 4, or 8%. Color nlysis of red loves rust showed tht lmost ll loves hd deresed Hunter vlues. Loves were found to eome greener s the level of DDGS sustitution inresed. Color nlysis of interior struture of these loves reveled tht ll loves exhiited inresed Hunter vlues. The interior struture eme notly drker nd redder s the level of DDGS inresed. These trends found y Rso et l. (199) prllel the trends found in our study. An inrese in drk pigments (due to the ddition of DDGS) hs lso een found in study ompleted y Brohetti et l. (1991). Bredrum olor drkened nd Hunter L vlues deresed s DDG level inresed. Our redrum nd rust Hunter L vlues lso showed deresing trend s DDGS sustitution inresed. Hunter L vlues re inditive of produt rightness, s vlue of indites lk nd 1 indites white. The DDGS dded ws golden yellow from drk pigments mostly loted in the orn lipids. Drker olors my lso hve een due to het (during drying), whih used undesirle Millrd rowning. This type of rowning is hemil retion etween reduing sugrs (i.e. D-gluose) nd free mino id or mino group (Fennem, 1996). 89

15 A B Crust Hunter Vlue SSL Crum Hunter Vlue e de d d DDGS 25 5 DDGS 25 5 C D Pek Height (m) d Side Height (m) Flou e de d DDG 25 5 DDG 25 5 E F Pek Height (m) d Length (m) Flo DDG 25 5 DDG 25 5 G Pek Height (m) d d SSL DDGS Figure 5. Tretment omintion effets on physil properties due to flour type, SSL, nd DDGS levels (A); etween rum Hunter vlues, flour (1=ll-purpose & 2=red), nd DDGS levels (B); etween pek height,, nd DDGS levels (C); etween side height, flour, nd DDGS levels (D); etween width, SSL, nd DDGS levels (E); etween length, flour, nd DDGS levels (F); nd etween pek height, SSL, nd DDGS levels (G). Overll, s DDGS levels inrese red pigments in the rum lso inrese while pek height, side height, nd length derese. As SSL inreses red pigments in the rust, width, nd pek height derese. Error rs represent ± 1 stndrd devition 9

16 Tle 4. Min effets for proximte omposition of prepred reds 1 Protein (% d) Ash (% d) Lipid (% d) Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. Tle 5. Min effets for physil properties of prepred reds 1 Strength (MP) Stiffness (MP) Moisture (% w) Wter Ativity Men St. Dev. Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. 91

17 Tle 5. Min effets for physil properties of prepred reds 1 (Cont.) L-Crust -Crust -Crust L-Crum Men St. Dev. Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. Tle 5. Min effets for physil properties of prepred reds 1 (Cont.) -Crum -Crum Side Ht. (m) Pek Ht. (m) Men St. Dev. Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. 92

18 Tle 5. Min effets for physil properties of prepred reds 1 (Cont.) Width (m) Length (m) Mss (g) Men St Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. Pek height nd side height deresed s the perentge of DDGS inresed. Rso et l. (199), lso found deresed lof volume on the mjority of red loves with 4 or 8% distillers grins sustitution. O Plk et l. (1989) ompleted study of ked produts ontining sour msh orn distillers dried grins. Three of four ked produts with vrious distillers sustitution levels resulted in deresed lof volumes: dinner rolls (17 or 33%), nut rolls (33%), nd rrot oonut red (4%). The derese in volume ws thought to hve een due to the dilution of gluten, prtiulrly in yest-levened produts, long with other ftors tht ompny the ddition of DDGS to whet dough systems. Inresed onentrtions of fier results often sor more wter (Dreese & Hoseney, 1982). Fier moleules n e inorported more esily into food system one the fier moleules re softened. Fier plys mny roles in food mtrix, suh s providing struture nd ulk, s well s modifying rheologil properties (Fennem, 1996). If firous mterils re not softened vi hydrtion, the struture my e ompromised due to the utting of gluten strnds, thus diminishing infltion nd struture. In this study, width deresed s the perentge of SSL nd DDGS inresed. The SSL s purpose ws to ondition nd filitte dough qulity; however, inresed quntity of DDGS hd n opposite effet, ltering red funtionlity. Length of red loves deresed s the quntity of DDGS inresed, whih reinfored tht higher replement rtes of DDGS impted size nd shpe. Pek height deresed s SSL nd DDGS sustitution inresed. This showed how red loves hd higher pek height when % SSL ws used ompred to.15% SSL, whih indited tht.15% ws not signifint quntity to mke muh differene in enhning dough nd lof properties. Brohetti et l. (1991) nlyzed red with 5, 1, nd 15% DDG sustitution. Results indited tht t 15% DDG sustitution level, red lof volume lso deresed. This volume derese is refleted in deresed pek height, side height, length, nd width prmeters. Tsen et l. (1983) nd Mord et l. (1984) hve lso found similr results. The more DDGS inluded into the red, the less whet flour, whih dilutes the mount of gluten proteins ville. It is lso possile tht inresed wter sorption n negtively ffet the rtio of whet flour-to-wter (3:1), thus preventing idel gluten formtion (Fennem, 1996). Additionl wter my disrupt intertions tht n ond the struture together. Bred loves with higher DDGS ontent my hve een mnipulted pst mximum resistne, thus resulting in derese in resistne, whih reks down the gluten struture. Finlly, the ddition of lumin- nd gloulintype proteins dversely ffets red volume nd gluten struture. Therefore it is importnt to monitor the ddition of these proteins into ked produts (Fennem, 1996). Height, shpe, nd olor differed mong the flour tretment omintions (Figure 6). Additionl imges showed the grin qulity, olor, size, nd struture of enter ut slies (Figure 7). As the quntity of DDGS repled inresed, ell struture of loves eme inresingly ompt, dense, nd thiker. 93

19 3.2.3 Sujetive Mesurements Tle 6 shows results for the sujetive king qulity nlysis. As the perentge of DDGS inluded in the red formtion inresed, signifint differenes ould e found mong uniformity, size, thikness, grin, tenderness, softness, nd rum olor. No signifint differenes were found etween the perentge of SSL or the other independent vriles. The type of flour hd signifint effet on softness. Figure 8 illustrtes the effets on softness nd DDGS sustitution. As the perentge of DDGS inresed, softness deresed. This ws expeted s the DDGS ws highly firous, whih hs previously een shown to lter the grin struture of the food mtrix. Brohetti et l. (1991) tested sensory hrteristis of reds with DDG replement. Breds with 1% nd more DDG sustitution hd less uniform ell distriution nd hrsher texture thn red tht ws onsidered idel. Their findings indited dverse effets of inresed DDG onentrtions tht ffeted sensory nd texturl hrteristis. They lso found tht s DDGS replement inresed, the severl properties were negtively ffeted, inluding ell uniformity, ell thikness, grin ondition, texture tenderness, texture softness, nd rum olor. This issue ould possily e fixed if DDGS refinement proesses ould result in extremely fine DDGS flour. 94

20 Figure 6. Initil lof profiles show differenes in shpe, olor, nd texture etween experimentl tretments. As the quntity of DDGS inresed physil dimensions suh s lof volume, height, nd length deresed. DDGS sustitution resulted in lof olor tht ws drker s well 95

21 Figure 7. Center slies show differenes in texture nd ell struture. Loves with high DDGS levels tended to hve smll, losed ells with thik ell wlls ompred to the open ells for loves without DDGS sustitution 96

22 12 1 Softness d d 2 DDGS Figure 8. Tretment omintion effets etween, flour (1=ll-purpose & 2=red) nd DDGS levels on red softness. Overll, s the quntity of DDGS inresed the softness qulities exhiited y the red loves deresed. Error rs represent ± 1 stndrd devition. Differing letters indite signifint differenes etween tretment omintions (p <.5, LSD) Tle 6. Min effets for sujetive qulity tests for prepred reds 1 Uniformity Size Thikness Grin Men St. Dev. Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. 97

23 Tle 6. Min effets for sujetive qulity tests for prepred reds 1 (Cont.) Moistness Tenderness Softness Crum Color Men St. Dev. Men St. Dev. Men St. Dev. Men St. Dev. DDGS (%) SSL (%) All-purpose Bred for given min effet, differing letters etween levels for given property signify signifint differenes (p <.5, LSD); St. Dev. is +/- 1 stndrd devition. 3.3 Correltions nd Multivrite Anlysis Liner orreltions were determined (Tle 7), these re not inditive of ustion, nor do they represent reltionships found in non-liner ehvior. As red mss inresed so did red protein (r=.863), flour protein (r=.864), red sh (r=.91), flour sh (r=.893), red lipid (r=.856) nd flour lipid (r=.866). These hemil properties oviously impted the finl physil ondition of red loves. s tht re rih in nutrients my produe inresingly dense loves of red. Wter sorption (r=.84) of the flour lso inresed s red mss inresed. This my indite n inresed quntity of wter retined nd not relesed s stem during king proesses. Also, wter sorption inresed s red protein (r=.953) nd flour protein (r=.967) inresed, inditing protein moleules my e inresed uilding to hydrtion. Results lso show Hunter nd vlues were positively impted y hemil properties s well. These vlues inresed s the quntity of red protein ( vlues r=.835 nd vlues r=.878), red sh ( vlues r=.878 nd vlues r=.886), nd red lipid ( vlues r=.82 nd vlues r=.844) inresed. As red protein ontent inresed, stility in the dough system deresed (r=-.855). As the replement rte of DDGS inreses, more protein is dded to the food mtrix. DDGS hs mny ftors, prtiulrly fier, tht my prevent the oproduts from eing esily inorported into dough. Also, s the ontent of flour sh inreses, softness dereses (r=-.973). This derese in softness my e due to the inresed quntity of nutrients nd non-nutrient residues, mostly inresing from rising sustitution of DDGS. In terms of multidimensionl spe, Prinipl Components Anlysis ws used to exmine the dt distriution when onsidering ll independent nd dependent vriles simultneously (Figure 9). Overll, the ovrine mtrix ppered to e etter suited to exmine this dt set, s it required fewer omponents (2 vs. 1) to summrize the vrine in the dt. As shown, three vriles were most influentil, nd thus hd the gretest influene on the dt, inluding DDGS level, red mss, nd stility. It lso ppered tht when onsidering the first two prinipl omponents there ws lustering in the dt, nd this ws speifilly due to the DDGS level. 98