Effect of part-baking time, freezing rate and storage time on part-baked bread quality

Abstract In the baking industry, different processes and methods of freezing have been used for breadmaking to preserve a quality comparable to that of fresh bread. In this study, the effect of part-baking time, freezing rate, and frozen storage time on part-baked French bread quality was determined. The bread was part-baked for 0, 3 and 6 min, frozen at slow (0.15 °C/min) and fast (1.75 °C/min) freezing rates, stored under freezing conditions for up to 56 days and thawed every 14 days. Part-baked bread was rebaked, and the SV and firmness at 2, 24 and 48 h were obtained. An experiment with a factorial design of 3×2×5 (3 part-baking time, 2 freezing rates and 5 frozen storage times) with analysis of variance (ANOVA) at a confidence level of 95% was carried out. The highest SV was obtained at 6 min of part-baking at a slow freezing rate and decreased as the frozen storage time increased. In contrast, TPA showed that bread firmness increases when the specific volume decreases, and the highest firmness is at 0 min of part-baked time. Relatively long part-baking times allow for firm crumb formation with limited damage to the structure and therefore bread with optimal quality.

摘要：在烘焙行业中，为维持面包品质与鲜制产品相当，从业者已采用多种工艺与冷冻方法用于面包制作。本研究探究了半烘烤时长、冷冻速率及冷冻储存时长对半烘烤法式面包品质的影响。实验将面包分别进行0、3、6分钟的半烘烤，以慢速（0.15℃/min）与快速（1.75℃/min）两种速率冷冻，随后置于冷冻环境中储存最长达56天，并每14天解冻一次。将半烘烤后的面包进行复烘烤后，分别在2、24、48小时测定其比体积（specific volume, SV）与硬度。本实验采用3×2×5的析因设计（包含3个半烘烤时长水平、2种冷冻速率、5个冷冻储存时长水平），并以95%置信水平开展方差分析（analysis of variance, ANOVA）。结果显示，在慢速冷冻条件下半烘烤6分钟的面包比体积最高，且比体积随冷冻储存时长的延长而降低。与之相反，质构分析（texture profile analysis, TPA）结果表明，面包硬度随比体积降低而升高，半烘烤0分钟的面包硬度最高。较长的半烘烤时长可使面包屑形成紧实结构且结构损伤有限，从而获得品质最优的面包。