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Effect of Growing Environment of Soft Wheats on Amylose Content and Its Relationship with Cookie and Sponge Cake Quality and Solvent Retention Capacity

¹National Agricultural Research Center for the Hokkaido Region (Memuro), Shinsei, Memuro, Hokkaido 082-0081, Japan. ²Corresponding author. Phone: +81-155-62-9210. Fax: +81-155-61-2127. E-mail: zenta@affrc.go.jp ³Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan. ⁴National Institute for Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8518, Japan.

The effect of growing environments of soft wheat on amylose content and its relationship with baking quality and solvent retention capacities (SRC) was investigated. Near-isogenic soft wheat lines of Norin 61 differing in granule-bound starch synthase (Wx protein) activity and grown in three different regions of Japan: Hokkaido (spring-sown) for 2006 and 2007, Kanto (autumn-sown), and Kyushu (autumn-sown) for 2007 were evaluated. Spring-sown samples produced grains of greater protein content (10.9–12.4%) than autumn-sown samples (7.3–9.1%). In contrast, spring-sown samples of 2007 with higher maturing temperature had lower amylose content (25.5% for Norin 61) compare to the autumn-sown and spring-sown samples of 2006 (27.6–28.4% for Norin 61). Amylose content was strongly correlated to sugar snap cookie (SSCD) diameter (r = 0.957–0.961; n = 10, all samples; P ≤ 0.001, r = 0.701–0.976; n = 7 partial waxy and nonwaxy samples; and Japanese sponge cake (JSCV) volume r = 0.971–0.993; n = 10; P≤ 0.001, r = 0.764–0.922; n = 7 partial waxy and nonwaxy samples), regardless of seeding season and growing conditions. The strength of the JSVC-amylose relationship (slope) was similar among the three regions, whereas the strength of the SSCD-amylose relationship was slightly weaker for spring-sown samples and slightly stronger for partial waxy and nonwaxy autumn-sown samples. Among of the four solvents (water, solutions of sodium carbonate, sucrose, or lactic acid), water-SRC showed the greatest correlation to amylose content (r = –0.969 to –0.996; n = 10; P ≤ 0.001, r = –0.629 to –0.983; n = 7 partial waxy and nonwaxy samples), indicated that amylose content can be accurately estimated from the water-SRC within the samples from the same grown environment.