Asian Salted Noodle Quality: Impact of Amylose Content Adjustments Using Waxy Wheat Flour

Cereal Chem. X()(4):437-445 Fourteen l10ur blends of two natural wild-type wbeat (71'iticlIllI lIestiVll1n L.) nours, 'Nuplains' and 'Centum', blended with one waxy nour sample were chamcterized and processed to Asian salted noodles. The flour amylose content range was <1-29%. Damaged starch contents were lOA, 7.0, and 6.6% for the waxy wheat, Nuplains, and Centum, respectively. The waxy flour farinograph water absorption was as high as 79.5%, ",20% higher than the wild-type flours. Because two types of starch granules (wild-type and waxy) existed in the flour blends, two peaks at 82°C (waxy) and 95°C (wild-type) were found in the RVA pasting curves. Reduced amylose content caused high tlour swelling Wheat (Triticum lIestivul11 L.) starch, as the most abundant component in wheat Hour, is composed of two types of glucose polymers, amylose and amylopectin. Amylose has long linear chains of D-glucopyranose units joined by ex. (I ~4) linkages. Amylopectin has highly branched structures, has a high molecular weight, and contains both ex. (I ~4) and ex. (I ~6) linkages of Dglucopyranose units (Lineback and Rasper 1988). Chemical composition, such as the amylose content or amylose-to-amylopectin ratio, determines thermal and pasting properties of starch that control the quality of final products and product shelf life. The structure, phase transitions, and interactions of starch with food constituents attract considerable resew'ch interest (Biliaderis 1992). As in other plants, the synthesis of wheat amylose seems to be governed by the granule-bound starch synthase I (GBSS, EC 2.4.1.21); GBSS is also called waxy protein (Graybosch 1998). Amylopectin synthesis is much more complicated (Ball et al 1996). Common wheat has three genetic loci encoding GBSS. When all three GBSS genes are present and functional, the grain is referred to as wild-type (Bettge et al 2000). The typical amylose content of wild-type whcat is ",27 ± 2% based on total starch. When endosperm starch is composed exclusively or predominantly of amylopectin (i.e., the plant lacks all functional GBSS genes), it is referred to as glutinous or waxy (Erikkson 1969). When only one or two GBSS genes are functional, the grains have intermediate levels of amylose and are referred to as partially waxy (Nakamura et al 1992, I 993a,b; Yamamori et al 1994). Waxy endosperm has been identified in several crops ineluding maize, rice, barley, sorghum and amaranth (Erikkson 1969). Although wheat is one of the most signiticant cereal crops in the world and improvement I Presented at the AACC 86th Annual Meeting, October 200 I. A joint contribution of the University of Nebruska Agriculture Research Division and the United States Department of Agriculture. Agriculture Research Service as Journal Series l'npc,' No. 13818. 2 Postdoctoral research associate and professor, respectively. Department of Food Science and Technology. University of Nehraska, Lincoln. NE 68583-0919. .1 Corresponding author. E-mail: djaekson I @unl.cdu. Fax: 402-472-1693. 4 USDA-ARS, 362C Plant Science Hall. University of NebnL~ku, Lincoln, NE 68583-0915. Names arc necessary to report factually on available data: however, the USDA neilhel' guuruntees nor wurrunts the standard of the product. and the use of the name by the USDA implies no upproval of the product to the exclusion of others that may also be suitahle. 5 Professor. Department of Biometry. University of Nehraska. Lincoln. NE 685830712. Publication no. C-2003-0615-05R. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. American ASSOCiation of Cereal Chemists, Inc., 2003. volume and power and low falling number. Significant effects of nour amylose content on noodle processing and textural (eating) qualities were found in the study. Noodle qualities, as reflected in covariate analysis. were not significantly affected by the flour blend's protein content, SDSsedimentation volume, mixograph dough development time, or mixograph tolerance score. The absel1l;e of covariate (protein quantity and quality) effects for the food system (flour) uscd in this study is a very desimble design for the functional studies of starch components. The optimal flour amylose content range for Asian salted noodle prodlll:ts was 21-24%. of its grain quality is desirable, the waxy mutations have not been identified in most hexaploid wheat (Otobe et al 1997). Because waxy wheat starch is amylose-free, waxy tlour shows unique sturch thermal and pasting properties (Zeng et al 1997: Graybosch et al 20(0). Among Asian noodles, the salted noodle product is very popular in most Asian countries such as China, Japan, and Korea (Huang 1996; Nagao 1996; Hou 200 I). Flour components contribute to the tinal noodle product quality, including both protein quantity and quality (Oh et al 1983; Huang and Morrison 1988; Raik et al 1994; Crosbie et al 1999), starch characteristics (Moss 1980: Toyokawa et al 1989; Konik et al 1993, 1994; Hatcher et al 20(2). lipids (Mohri 1980; Rho et al 1989; Jun et al 1998a), and colorreluted enzymes (Miskelly 1984; Hatcher and Kruger 1993: Kruger et al I 994a,b; Vadlamani and Seib 1996). As early as 1977, Nagao and coworkers found that certain Australian wheats had distinct flour gelling temperatures and gave superior noodle quality. This was one of the first indications that starch properties were impoltant for noodle quality (Zhao et al 1998). The study results of Moss (1980) also indicated that the high pasting strength of starch was the most important factor goveming the eating quality of Japanese white noodles (udon). Low starch paste viscosity was desirable for Chinese-type noodles (ramen). Oda ct al (1980) found there were good con-elations between amylogram values and amylose content with udon sensory eating qualities. Higher starch and flour paste peak viscosity, lower gelatinization and peak temperatures. higher breakdown, and higher swelling power and volume resulted in better Asian salted noodles (Endo et al 1988; Crosbie 1991: Panozzo and McCormick 1993). Lower amylose contcnts were related to higher starch swelling properties and beller noodle qualities (Miura and Tanii 1994; Wang and Seib 1996; Jane et al 1999; Noda et al 2001). A higher proportion of A-type (large) starch granules, lower protein content (quantity) but highcr protein quality, and softer grain texture (hardness) gave beller salted noodle qualities (Konik et al 1993; Black et al 2000). Australian Standard White (ASW) wheats from Western Australia, which have many of the traits listed above, arc the preferred wheats fi.ll' Asian salted noodle products, especially for udon (Crosbie 1991; Konik and Miskelly 1992). Asian noodle customers use noodle color (including raw noodle discoloration), surface appearance, texture, taste. and weight gain during cooking as the main discriminating criteria for determining quality (Lee et al 1987; Konik and Miskelly 1992; Hatcher et al 2(02). Instead of any single flour constituent, many factors combine to influence the noodle qualities (Miskelly and Moss 1985). In breadbaking and flour milling, Graybosch et al (1993) found no Vol. 80, No.4, 2003 437 single biochemical component capable of explaining more than 41 % of the variation in any given quality parameter. Similarly, no single biochemical component was highly related to all quality attributes (Graybosch et al 1993). Crosbie (1991) rcported that flour swelling volume accounted for 48% of the variation associatcd with noodle texturc scores. Baik et al (1994) indicated that both protein content and quality should be considered in the evaluation of flour suitability for making oriental noodles. Batey et al (1997) found that the relationships between starch properties and Japanese noodle quality were complex. These workers also found that, while unrelated to each other, both the amylose content and the amylopectin structure appeared to be important for noodle quality. Therclill\:, when screening noodle wheats, consideration must be given to starch properties, the level and strength of protein, grain hardness, flour granulation, and enzyme activity (Konik and Miskelly 1992; Jun et al I 998b). To study the complex flour dough system, fractionation and reconstitution methods have been used widely in functionality studies of flour components for over 50 years (Rho ct al 1989). With the availability of waxy or partial waxy wheats, it becomes possible to allow food scientists to manipulate wheat amylose content without dilution of wheat gluten (Graybosch 1998; Graybosch et al 1998). This study attempto; to determine the impact of amylose content on Asian salted noodle quality. MATERIALS AND METHODS Wheat Samples One hard white wheat, 'Nuplains' (N), and one hard red wheat, 'Centura' (C), were selected for this study. Both cultivars are wildtypc wheats that were planted in Clay Center, NE, in 2000. A waxy wheat sample, obtained from a composite of waxy wheat experimental lines planted in Yuma, AZ, in 2000, was used to manipulate wheat flour amylose content. Wheat Milling All three wheat samples used in the study were milled into straight-grade Hours using a Buhler laboratory mill according to Approved Method 26-21A (AACC 2(00). The flour yields range was 66.1-71.5%. TABLE I Formulation ofAsiallSalted Noodles :Fi.0\D' n:a:% rob) Haiti' W.atet'> "'Slllt dissOlved ill water. 15·· 0,>' adjuated TOO ;2.()