ARTICLE IN PRESS - USDA

1 Journal of Cereal Science 44 (2006) 161 173 Gluten proteins from spelt (Triticum ) cultivars:A rheological and size-exclusion high-performanceliquid chromatography study$Tilman J. Schobera, , Scott R. Beana, Manfred Kuhnb,1aUSDA-ARS, GMPRC, 1515 College Avenue, Manhattan, KS 66502, USAbUniversity of Hohenheim, Institute of Food Technology, Section Cereal Technology, 70599 Stuttgart-Hohenheim, GermanyReceived 22 December 2005; received in revised form 16 May 2006; accepted 25 May 2006 AbstractThe aim of this study was to understand the chemistry of spelt (Triticum ) gluten in relation to its quality, to classifyEuropean spelt cultivars based on gluten quality, and to compare their protein compositions with those of modern wheats.

2 Glutenquality of two sets of 25 spelt cultivars was studied using dynamic oscillatory and creep tests, an SDS sedimentation test, moisturecontent of the wet gluten and wet gluten content. These data were compared with the results of size-exclusion HPLC analyses of the speltproteins. Significant correlations indicated that insoluble polymeric proteins (IPP) contributed resistance to deformation in creep tests,elasticity in oscillatory and creep tests, and swelling capacity of the gluten. Gliadins had the opposite effects, whereas the contribution ofsoluble polymeric proteins (SPP) depended on the type of test.

3 In creep tests (strain ) SPP behaved similarly to gliadins, inoscillation (strain ) they tended to increase elasticity. In comparison to hard red winter wheats, spelt was characterized by lowerIPP, but higher gliadins and SPP, resulting in softer and less elastic glutens. A wide variation in gluten quality was found among thespelts. Three groups could be identified by cluster analysis (one closer to modern wheat, a second typical spelt group and a third a poorquality group).Published by Elsevier :Size-exclusion-HPLC (SE-HPLC; SEC); Rheology; Gluten proteins; Spelt wheat (Triticum )1.

4 IntroductionSpelt (Triticum Thell.) is anancient subspecies of modern bread wheat ( ). Until the beginning of the 20thcentury, spelt was the predominant grain for breadproduction in many regions, for example in southwesternGermany, and parts of Switzerland and Austria. Sincethen, however, it has largely been displaced by modernwheat (Kling, 1993;Winzeler and Ru egger, 1990). This isdue to spelt s lower yield and its long straw with a tendencyto lodge, especially if levels of nitrogen fertilizer applied aretoo high. Furthermore, as spelt is a hulled grain, adehulling step prior to milling is required (Campbell,1997;Kling, 1993).

5 In the past few decades, however, spelt has undergone arenaissance as a niche product. This may be due to theperception that it is a healthier , more natural , or less over-bred grain than modern wheat. Consequently, thereare an increasing number of international publications onspelt food quality, spelt proteins, rheology of spelt doughor gluten, or comparisons of spelt and modern wheat fromARTICLE IN $ - see front matter Published by Elsevier :AG, albumins and globulins; db, dry basis; EP,extractable proteins; fp, flour protein;jG j, complex shear modulus(absolute value); Gli, gliadins; IPP, insoluble polymeric proteins; SE-HPLC, size-exclusion high-performance liquid chromatography; SPP,soluble polymeric proteins.

6 Wb, wet basis$Names are necessary to report factually on available data; however,the usda neither guarantees nor warrants the standard of the product,and use of the name by the usda implies no approval of the product tothe exclusion of others that may also be suitable. Corresponding author. Tel.: +1 (785) 776 2708;fax: +1 (785) 537 ( Schober). (Legros and Castille, 1972;Ruibal-Mendieta et al.,2004), Canada (Abdel-Aal, 2003;Abdel-Aal et al., 1995,1998), Czech Republic (Dvor a c ek et al., 2001, 2002;Moudry and Dvor a c ek, 1999), Germany (Belitz et al.,1989;Gra ber and Kuhn, 1992;Martini and Kuhn, 1999;Schober, 2001;Schober and Kuhn, 2003;Seibel et al.)

7 ,1989), Italy (Marconi et al., 1999, 2002;Piergiovanni andVolpe, 2003;Piergiovanni et al., 1996), Poland (Grela,1996), Slovak Republic (Bojn anska and Franc a kova ,2002), Switzerland (Siedler et al., 1994;Winzeler andRu egger, 1990), USA (Ranhotra et al., 1995, 1996),or international cooperations (Italy-Slovenia:Bonafacciaet al., 2000; Slovak Republic-Germany:Smolkova et al.,2000; Slovenia-Sweden:Skrabanja et al., 2001). Results ofthis international research allows comparisons across alarge variety of environments with different types ofmodern wheat as , very few differences between spelt andmodern wheat have been confirmed experimentally.

8 Inrespect to food quality, most of the studies found higherprotein contents for spelt than for modern wheat (Bona-faccia et al., 2000;Campbell, 1997;Dvor a c ek et al., 2001,2002;Marconi et al., 1999;Moudry and Dvor a c ek, 1999;Piergiovanni et al., 1996;Ranhotra et al., 1996), althoughin some, the opposite was reported (Grela, 1996;Ranhotraet al., 1995) and in some cases differences were notsignificant. Overall, the values found for proximatecompositions and minor components in spelt are withinthe range found among modern wheats (for an overview,seeCampbell, 1997). Spelt gluten tends to be moreextensible and less elastic than gluten from modern wheat,resulting in the typical, weaker spelt doughs (Abdel-Aalet al.)

9 , 1997, 1998, 1999;Gra ber et al., 1994;Marconi et al.,1999, 2002;Ranhotra et al., 1995). As a consequence, forbread, rolls or two-layer flat bread, high doses of ascorbicacid, shorter mixing times, reduced water addition orlonger dough rest times have been proposed (Abdel-Aalet al., 1998, 1999;Gra ber et al., 1994;Ranhotra et al., 1995;Seibel et al., 1989), and for pasta, high-temperature dryinghas been recommended (Marconi et al., 1999, 2002).It is important to emphasize that spelt is as harmful forceliac patients as modern wheat (Forssell and Wieser, 1995;Kasarda and D Ovidio, 1999).

10 Furthermore, althoughmany end-users seem to believe that spelt might betolerated by people with allergic reactions to wheat (notceliac disease), there is no supporting scientific evidence. Infact, in a single study with only one subject with severewheat allergy, this person was also allergic to spelt(Friedman et al., 1994). Clearly, until more research isconducted on the overall allergenicity of spelt, a wheatsubspecies, spelt cannot be recommended for people withwheat allergy. Spelt has, however, been shown tocontribute to genetic diversity within wheat (Abdel-Aal,2003;Siedler et al.)