Abstract: To clarify the effect of pre⁃harvest sprouting on wheat quality and steamed bread processing quality under natural field condition，wheat materials in years suffering severe pre⁃harvest sprouting were used as experimental materials. The samples were classified into four groups based on grain falling number：grain falling number≤100 s（severe sprouting），100—200 s （mild sprouting），200—250 s，and ≥250 s. Variation trends of wheat quality indicators as well as quality types of wheat with different sprouting degrees were analyzed. Meanwhile，based on the flour falling number requirements for different types of flour processing，the materials were classified into four groups with different sprouting degrees：flour falling number<200 s，200—250 s，250—350 s，and ≥350 s. The steamed⁃bread quality of wheat with different sprouting degrees，correlations between steamed⁃bread quality and wheat quality indicators，and threshold values of flour pasting parameters for different flour processing types were investigated. The results showed that most wheat quality indicators exhibited high coefficients of variation in the year suffering severe pre⁃harvest sprouting. The volume weight，hardness index，protein content，wet gluten content，water absorption and extensibility were the lowest when the grain falling number was<100 s，while stable when the falling number was≥100 s. Dough energy，development time，stability time，resistance and maximum resistance decreased with the increase of sprouting degree，while degree of softening increased.The peak viscosity，trough viscosity，final viscosity，breakdown and setback of flour declined distinctly with the increase of sprouting degree，peak time decreased gradually，while pasting temperature increased slightly.The grain falling number was extremely significantly positively correlated with volumn weight，development time，stability time，energy，resistance，maximum resistance，peak viscosity，trough viscosity，breakdown，final viscosity，setback and peak time，and significantly negatively correlated with pasting temperature. Compared with wheat materials with stability time>10 min and of 7—10 min，wheat materials with stability time<7 min and <3 min were more susceptible to pre⁃harvest sprouting.The steamed bread taste evaluation results revealed that as sprouting degree increased，all quality scores decreased. Steamed bread made from wheat with flour falling number<200 s exhibited the lowest aspect ratio，elasticity，surface color，surface structure，internal structure，toughness，stickiness，and taste scores，along with the lowest total score. In contrast，the steamed bread made from wheat with flour falling number≥350 s achieved the highest total score，and the scores for wheat with flour falling number between 250 s and 350 s were close to those for wheat with flour falling numbers≥350 s.The score of steamed bread was significantly or extremely significantly positively correlated with the flour falling number，wet gluten content，development time，peak viscosity，trough viscosity，final viscosity，setback and peak time.The average values and ranges of flour pasting indicators for wheat with different flour falling numbers showed that the trough viscosity，final viscosity，and setback exhibited stepwise changes with different flour falling number ranges.Therefore，these three indicators could also serve as characteristic parameters for estimating wheat sprouting degree in flour processing. Specifically，when the trough viscosity ≤165 cP，final viscosity ≤438 cP，and setback ≤273 cP，the flour was unsuitable for bread，steamed bread and noodle production.

Key words: Wheat, Sprouting degree, Falling number, Quality, Processing characteristics, Steamed bread, Pasting properties

摘要： 为了明确在自然环境条件下发芽对小麦品质及馒头加工品质的影响，以发芽程度较重年份的小麦材料为研究对象，根据籽粒降落数值将其划分为不同发芽程度的4类，即籽粒降落数值<100 s（严重发芽）、100~200 s（轻度发芽）、200~250 s和≥250 s，分析不同类材料品质指标的变化趋势，以及不同发芽程度小麦的品质类型；根据不同加工类型对面粉降落数值的要求将材料划分为不同发芽程度的4类，即面粉降落数值<200 s、200~250 s、250~350 s和≥350 s，分析不同类材料的馒头品质，及其与小麦品质指标的相关性，以及不同加工类型要求的面粉糊化参数阈值。结果表明，在穗发芽严重的年份，小麦大部分品质指标的变异系数较大。容重、硬度指数、蛋白质含量、湿面筋含量、吸水量和延伸性在籽粒降落数值<100 s时最低，在籽粒降落数值≥100 s时趋于稳定；能量、形成时间、稳定时间、拉伸阻力、最大拉伸阻力均随着发芽程度的加深减小，弱化度增大；面粉的峰值黏度、最低黏度、最终黏度、衰减值和回生值均随着发芽程度的增加呈大幅下降趋势，峰值时间呈缓慢下降趋势，糊化温度呈缓慢升高趋势。籽粒降落数值与容重、形成时间、稳定时间、能量、拉伸阻力、最大拉伸阻力、峰值黏度、最低黏度、衰减值、最终黏度、回生值和峰值时间均呈极显著正相关，与糊化温度呈显著负相关。与稳定时间>10 min和稳定时间介于7~10 min的小麦材料相比，稳定时间<7 min和<3 min的小麦材料更易发芽。馒头品尝评分结果表明，随着发芽程度的增加，馒头的各项评分指标降低。面粉降落数值<200 s的小麦材料制作的馒头的宽高比、弹性、表面色泽、表面结构、内部结构、韧性、黏性、食味得分均为最低，总分也最低；面粉降落数值≥350 s的小麦材料制作的馒头总分最高；面粉降落数值介于250~350 s和≥350 s的小麦材料制作的馒头总分接近。馒头总分与面粉降落数值、湿面筋含量、形成时间、峰值黏度、最低黏度、最终黏度、回生值、峰值时间均呈显著或极显著正相关。对比不同面粉降落数值小麦材料的面粉糊化特性指标平均值和变幅发现，最低黏度、最终黏度和回生值在面粉降落数值不同范围内呈阶梯式变化，因此，这3个指标也可用作面粉加工中预估小麦发芽程度的特征参数，即当最低黏度≤165 cP、最终黏度≤438 cP且回生值≤273 cP时，不能用于面包、馒头和面条加工。

关键词: 小麦, 发芽程度, 降落数值, 品质, 加工特性, 馒头, 糊化特性