JIA-2019-11

2661 Ji-Eun Kim et al. Journal of Integrative Agriculture 2019, 18(11): 2652–2663 showed the same tendency to the correlation in this study. However, KSSB showed positive correlation between optimum water absorption of Mixograph and whiteness index of crumb. NSCSB showed negative correlation between stress relaxation and WSRC, which was also found in NSCSB made from whole wheat flour (Wu et al . 2012), while KSSB showed negative correlation between stress relaxation and water absorption in Mixograph. The difference of correlations between two different styles of steamed bread, KSSB and NSCSB was because of different procedure for making steamed bread. Furthermore, no relationship in this study may be due to the hardness of Korean wheat cultivars, of which five cultivars showed soft kernel texture, carrying Pina-D1a and Pinb-D1a , and six cultivars had hard kernel texture, carrying Pina-D1b or Pinb- D1b (Table 2). Addo et al . (1991) reported that volume of steamed bread is positively correlated with protein content in soft type wheat, but no correlation is found in hard type wheat. Protein content and quality have influence on volume of NSCSB made from Chinese wheat cultivars and U.S. soft wheat (He et al . 2003; Ma and Baik 2016). 4.4. Quality attributes of steamed bread Glutenin and puroindolines compositions could be closely related to quality of NSCSB, although there was no report on the effect of these genetic compositions on KSSB. Glu-1 alleles could account for about 62% of quality of NSCSB prepared from Chinese and Canadian wheat cultivars (Lukow et al . 1990). Wheats carrying Glu-D1d allele might be associated with better NSCSB quality than wheats with Glu-D1a allele (Zhu et al . 2001). Wheat line with Glu-A1a , Glu-B1c , Glu-D1a , Glu-A3e , Glu-B3b and Glu-D3c had the highest total score of NSCSB in 25 near-isogenic lines with different Glu-1 and Glu-3 alleles (Jin et al . 2013). Hard wheat deletions at Glu-B1y and/or Glu-D1y loci produce good dough properties for NSCSB (Zhang et al . 2014). Glu- A1a or b , Glu-B1al and Glu-D1d alleles might be desirable for improving dough strength and quality of NSCSB from soft red winter wheats (Ma and Baik 2016). The relationship between genetic variations and steamed bread quality could be useful to improve quality of both NSCSB and KSSB, although limited wheat cultivars were evaluated in this study. 5. Conclusion This study was performed to identify relationship between physicochemical characteristics and quality attributes of steamed bread. Quality attributes of two different styles of steamed bread, Korean style steamed bread (KSSB) and northern-style Chinese steamed bread (NSCSB) were evaluated based on flour characteristics of Korean wheat (Shewry et al . 1992). Glu-D1 allele accounts for mixing properties in Chinese bread wheat genotypes, and Glu-D1d induces a longer mixing time than Glu-D1a (Liu et al . 2005). Chinese and CIMMYT wheat genotypes carrying Glu-B3d also exhibited a longer mixing time than those carrying other alleles (He et al . 2005; Liu et al . 2005). It was identified that six of seven Korean wheat cultivars carrying Glu-B3d allele also carried Glu-D1f allele, and they have a shorter mixing time than wheat cultivars carrying Glu-D1d allele in this study. Unique mixing properties of Korean wheat cultivars could be influenced by the narrow genetic background and high frequency of specific glutenin compositions, which especially are related to weak gluten strength, such as Glu- A1c , Glu-D1f , Glu-A3c and Glu-B1h alleles (Park et al . 2006; Shin et al . 2012; Cho et al . 2018). Protein characteristics and the proportion of gluten in Korean wheat cultivars are between those of Australian standard white and hard wheats (Cho et al . 2018). In pasting properties of starch, the measured values in this study were similar to the results of previous studies with Korean wheat cultivars, and there was no difference in Korean wheats (Kang et al . 2012; Kim et al . 2017). Hojoong showed lower amylose content and higher viscosity than other Korean wheat cultivars due to the Wx-B1b allele (Kim et al . 2017). Partial waxy wheat reduces amylose content and exhibits higher peak viscosity than wild-type at the waxy ( Wx ) protein, which is known as granule-bound starch synthase I (GBSS I; EC 2.4.1.21) controlling amylose content (Graybosch et al . 2003). Reduced amylose content and higher viscosity generally improve the texture quality of noodles and shelf-life of bread during storage (Graybosch et al . 2003). 4.3. Relation between flour characteristics and quality of steamed bread The differences of diameter, volume, height, whiteness index of crumb, and stress relaxation according to steamed bread making styles seem to be due to the differences in two types of steamed bread preferred by each country and the resulting differences in ingredients. Higher optimum water absorption and additive ingredients, such as shortening and baking powder are required for making KSSB compared to NSCSB because of the preference for soft and less sticky texture in Korea (Kim et al . 2001). Quality attributes of steamed bread was influenced by procedure for steamed bread making (Lin et al . 1990). In correlation between flour characteristics and quality of steamed bread, the correlation showed difference according to KSSB and NSCSB. Lin et al . (1990) and Huang et al . (1996) reported that ash content was correlated with whiteness index of surface in NSCSB. This correlation