JIA-2019-11

2654 Ji-Eun Kim et al. Journal of Integrative Agriculture 2019, 18(11): 2652–2663 screen with 0.25-mm openings. Pasting properties of starch were determined with a Micro Visco-Amylo-Graph device (Brabender, Duisburg, Germany). Starch (10.0 g, db) was suspended in 0.1% AgNO 3 solution (100 mL) and heated from 30 to 95°C at a rate of 7.5°C min –1 , held at 95°C for 5 min, cooled to 50°C at a rate of 5°Cmin –1 , and held at 50°C for 2 min under constant stirring (110 r min –1 ). Viscosity was expressed in Brabender units. Viscosities (peak and final) and holding strength of starch were recorded. Breakdown was calculated by subtracting the holding strength from the peak and final viscosities. Temperature at peak viscosity was also determined. 2.3. Allelic variations Genomic DNA was extracted from young leaf tissue (100 mg) using the Genomic DNA Prep Kit (Solgent Co., Korea) according to the manufacturer’s instructions. PCR was conducted with primers for Glu-1 allele-specific markers according to the methods illustrated in Liu et al . (2008) for Glu-A1 allele, Lei et al . (2006) for Glu-B1 allele, and Liu et al . (2008) and DeBustos et al . (2001) for Glu-D1 allele, respectively. PCR was conducted with primers for Glu-3 allele-specific markers according to the methods presented inWang et al . (2010) for Glu-A3 allele andWang et al . (2009) for Glu-B3 allele. The allelic variations for puroindolines were evaluated by the procedure described by Gautier et al . (1994). Amplified PCR fragments were separated on 1.5% agarose gels, stained with ethidium bromide, and visualized using UV light. 2.4. Steamed bread Steamed bread making was conducted in two different styles, KSBS and NSCSB. There were two differences between the two kinds of steamed bread, formulation and steaming time (Fig. 1). Steamed bread was prepared according to the procedure of Choi et al . (2011) and Ma and Baik (2016) with a minor modification. The ingredients of making KSSB formula consisted of 100.0 g (14% moisture basis, mb) of flour, 8.0 g of sugar, 5.0 g of shortening, 1 g of salt, 1.5 g of instant yeast (Lesaffre Yeast Co., Milwaukee, WI, USA), 1.0 g of baking powder (Jenico Foods Co., Ltd., Seoul, Korea) and distilled water. But, the ingredients of NSCSB were 100.0 g of flour (14% mb), 1.5 g of instant yeast and distilled water. The different optimum water absorption was used for making steamed bread, that 100% of Mixograph absorption was used for making KSSB but 80% of Mixograph absorption was used for NSCSB. Dough mixing was divided into two steps, of which the initial mixing was conducted with a 3/4 of Mixograph mixing time and the rest of the mixing time was continued in the second mixing. The amount of distilled water based on the Mixograph mixing time minus 2 mL was used in the initial mixing and 2 mL of distilled water was used in the second mixing. For the initial mixing, 90 g of flour and other ingredients were mixed in a pin mixer (National Mfg. Co., USA) with 102 r min –1 . Dough was fermented for 60 min at 32°C and 85% relative humidity in a proofing cabinet (Daeyoung Bakery Machinery Co., Ltd., Seoul, Korea). After the second mixing, the dough was sheeted by passing through the rolls of a 7-mm gap 20 times in a dough sheeter (Daeyoung Bakery Machinery Fig. 1 Procedure for steamed bread making of Korean style steamed bread (A) and northern-style Chinese steamed bread (B).