bread-making quality of italian durum wheat (triticum ...

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Loaf volume was correlated with alveo- ... Key words: Bread-making, durum wheat, new cultivars, quality -. /fa/. J. Food ... best cultivars for bread-making quality.

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BREAD-MAKING QUALITY OF ITALIAN DURUM WHEAT (TRITICUM DURUM DESE) CULTIVARS QUALITÀ PANIFICATORIA DI VARIETÀ ITALIANE DI FRUMENTO DURO M. PALUMBO, A. SPINA and G. BOCCINI Istituto Sperimentale per la Cerealicoltura, Sezione di Catania, Via Varese 43, 95123 Catania, Italy - e-mail: [email protected] '

ABSTRACT

RIASSUNTO

The bread-making characteristics of Vengono riportati i risultati delle ana23 Italian durum wheat cultivars grown lisi relative alla qualità panificatoria, in Sicily in 1998-1999 are reported. condotte su 23 varietà di grano duro Protein content, farinograph curves, al- coltivate in Sicilia nel biennio 1997/98veographic parameters, glutenin com- 1998/99. Sui campioni di semola sono position and sernolina colour were de- stati determinati il contenuto proteico, termined and an experimental bread- i parametri farinografici ed alveografici making test was carried out. Environ- nonché il colore della semola; è stato mental conditions strongly affected thè inoltre effettuato il test di panificazioqualitative characteristics of thè varie- ne sperimentale. Le condizioni ambienties. Ali thè technological evaluations tali hanno influenzato sensibilmente le showed a wide range of variation also caratteristiche qualitative delle varietà arnong genotypes in ali environrnents. in prova. I risultati delle valutazioni Loaf volume was correlated with alveo- chimiche e tecnologiche hanno mostragraphic P/L. The new cultivars Colora- to in tutti gli ambienti un'ampia varia- Key words: Bread-making, durum wheat, new cultivars, quality /fa/. J. Food Sci. n. 2, voi. 14 - 2002

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do, Mongìbello, Varano and Svevo are well suited for bread-making and are characterized by thè "7+8" or "6+8" HMW glutenins.

INTRODUCTION Early baking studies showed that durum wheat flours were unsuitable for bread-making (JAGO and JAGO, 1921; GERHARD, 1925; WIHLFAHRT, 1928). However, SHEPARD (1903) showed that many people preferred bread made frorn durum wheat to ordinary bread, due to its palatable and nutritional qualities. GEDDES (1932) reported that bread made from durum wheat remained fresh for a longer time than bread made from common wheat flours. He also indicated that durum wheat was used extensively for bread-making in Russia. KALTSIKES et al (1968) produced a durum wheat genotype with high breadmaking quality by crossing a durum wheat variety with a common bread wheat variety. AMENDOLA and LUNDBERG (1970) reported that durum flour was used for French and Italian types of bread which require a high protein content. The development of strong gluten durum wheat cultivars in Italy, Canada and thè U.S.A. has increased their potential use as a bread flour. DEXTER et al. ( 1981 ) reported that some new cultivars of durum wheat have approached acceptable levels for baking. They also found no fundamental differences in thè functional properties of durum wheat gluten compared with that of common wheat. Genotype is an important factor that affects thè bread-making characteristìcs of durum flour (JOSEPHIDES, 1982). DEXTER et al (1994) showed thè importance 124

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bilità anche fra i genotipi. Il volume del pane è risultato correlato con il P/L alveografico. Le nuove cultivar Colorado, Mongibello, Varano e Svevo sono emerse per elevata qualità panifìcatorìa. Queste varietà sono caratterizzate dalla presenza delle glutenine APM "7+8" o "6+8". of protein content on durum bread volume and thè impact that fermentation time can have on bread quality. AMMAR et al (2000) have postulated that gluten extensibility is an important factor for determining durum bread-making quality. RAG et al (2001) pointed out thè importance of thè balance between gluten elasticity and extensibility. In a number of regions in southern Italy, bread is mainly made from durum wheat. Therefore, BOGGINI (1985) evaluated thè bread-making qualities of 25 durum wheat cultivars that were grown in Italy in 1984. Further studies (BOGGINI et al, 1988, 1994) showed that thè best cultivars for bread-making quality were characterized by thè y "45" gliadin band. BOGGINI and FOGNA (1989) investigated thè bread-making quality of other Italian durum wheat cultivars and thè influence of thè high molecular weight (HMW) glutenin subunits on this characteristic and found that thè HMW glutenin composìtion appeared to affect bread-making quality. The cultivars having thè subunit pair "7+8" produced higher bread volumes than cultivars with thè subunit "20" or thè subunit pair "6+8". AMMAR et al. (2000) and PENA et al. (1994) also showed thè relationship between HMW glutenin composition and bread-making quality, while LIU et al. (1996) reported a relationship between gluten strength and LMW glutenin alleles. CUBADDA et al (1987) and PASQUI et al. (1991) have demonstrated that bread volume, softness and shelf-life depend

on thè alveographic characteristics of thè dough and doughs wlth low P/L and moderate W values give high bread volume and soft crumbs. QUICK and CRAWFORD (1983) and DICK (1988) in thè U.S.A., OZEN (1986) in Turkey, BAKHSHI and BAINS (1987) in India and WILLIAMS et al. (1988) in Syria and Jordan evaluated thè bread-making characteristics of thè durum wheat varieties grown in these countries and thè possibility of using durum wheat flour to improve thè quality of common wheat. BOGGINI and FOGNA (1990) blended common wheat flour of poor bread-making quality with flours from 29 Italian durum wheat cultivars. The addition of 25% durum wheat flour significantly increased thè loaf volume. The same results were obtained by BOYACIOGLU and D'APPOLONIA (1994 a, b, e), who also demonstrated how additives and baking procedures influenced durum bread characteristics. This paper reports thè bread-making characteristics of Italian durum wheat genotypes as well as thè evolutionary trends of these characteristics in thè Italian germplasm. MATERIALS AND METHODS Nineteen new Italian cultivars and four widespread varieties of durum wheat (Creso, Duilio, Ofanto, Simeto) were grown in four Sicilian environments: Libertinia and Mineo, in 1997-98 and Libertinia and Aragona in 1998-99. Following procedures described by BOGGINI et al. (1994), grain samples were milled using an experimental laboratory mili (Bona, Monza, Italy) with sieves of 54 and 42 GG and thè qualitative parameters of thè semolina were analyzed. Protein content (% dry matter) was determined with an Infratec 1229 Grain Analyzer (Foss Tecator, Hòganàs, Sweden) by Near Infrared Transmittance (NIT), using a calibration based on Kjel-

dahl nitrogen determinations. Farinograph curves were obtained using a model 810105001 Brabender instrument (Brabender OHG, Duisburg, Germany). Water absorption, mixing time, degree of stability and softening index (12 min after peak time) were measured (AACC, 1979b). Alveograph parameters, strength of thè dough (W) and ratio of tenacity (P) to extensibility (L), were determined using a model MA87 Chopin alveograph (Group Tripette & Renaud, VilleneuveLa-Garenne, France) according to UNI (1995). The bread-making test was carried out according to thè AACC procedure (1979a) which was modified for durum wheat by BOGGINI and FOGNA (1989) to obtain two loaves from 100 g of semolina, each. The characteristics of loaf volume, weight, crust roughness and colour and crumb porosity were recorded. Crumb porosity was estimated by means of thè Dallmann scale. In Italy crumb colour is considered an aesthetic advantage for durum wheat bread. Therefore in thè second year of trials, thè yellow semolina colour index (b*) was determined using a model CR 300 Minolta colorimeter (Minolta, Osaka, Japan), by means of a CIE colour System and using thè colour space L* a* b*. Statistical analysis of variance of thè qualitative parameters was carried out and thè results were then represented in "box plot" (Systat software) where thè centre horizontal line indicates thè median of thè samples, thè length of each box shows thè range within which thè centrai 50% of thè values fall and thè whiskers show thè range of non anomalous values observed (that fall within 1.5 Hspreads of thè hinges). Values between thè inner and outer fences are plotted with asterisks. Values beyond thè outer fences, called far outside values, are plotted with empty circles. SDS-PAGE electrophoretic patterns of low molecular weight (LMW) and high molecular weight (HMW) glutenin subunits were determined for ali genotypes, /fa/. J. Food Sci. n. 2, voi. 14 - 2002

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according to thè method described by DAL BELIN PERUFFO et ai. (1981). RESULTS AND DISCUSSION Ali thè varieties were characterized by LMW glutenin type 2 and HMW at thè locus Giù Al type "Nulli". The subunits at Giù Bl were quite different (Table 1). The Colosseo and Nefer cultivars had thè "13+16" gluteninic component and Parsifal "6+17", which are usually only present in small quantities in Italian germplasm. The niajority of cases were characterized by thè "7+8", "6+8" and "20" composition. It is also important to note that thè Iride and Italo varieties were Table 1 - Glutenin composition and yellow index of thè 23 durum wheat cultivars. Cultivars

BRONTE CICCIO COLORADO COLOSSEO CRESO DUILIO DURFORT FORTORE GARGANO GIANNI IRIDE ITALO MONGIBELLO NEFER OFANTO PARSIFAL PLATANI SAN CARLO SIMETO SVEVO TRESOR VALBELICE VARANO

HMW glutenins subunits at Giù - B1

Yellow index of semolina