Effect of freezing rate and frozen storage on the rheological properties and protein structure of non-fermented doughs

• Published in: Journal of food engineering Vol. 293; p. 110377
• Main Authors: Yang, Jingjie, Zhang, Bo, Zhang, Yingquan, Rasheed, Mohsin, Gu, Shuqin, Guo, Boli
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2021
• Subjects: Frozen non-fermented dough; Micro-structure; Protein structure; Rheological properties; Frozen non-fermented dough; Protein structure; Micro-structure; Rheological properties
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2020.110377

The objective of this study was to investigate the effects of the freezing rate and frozen storage duration on the rheological properties and protein structure of the non-fermented dough. The samples were frozen at −40 (0.149 °C/min), −30 (0.086 °C/min) and −20 °C (0.039 °C/min), and stored at −18 °C for 30 days. Freezing at −40 and −30 °C led to minimal changes in the rheological properties of the non-fermented dough. Additionally, −40 °C freezing resulted in higher maximum creep compliance (Jmax) and lower zero shear viscosity (η0). The content of glutenin macro-polymers (GMP) decreased gradually throughout the storage period, while that of free thiol groups (-SH) increased significantly, especially for samples frozen at −20 °C. Fourier transform infrared (FTIR) spectroscopy showed that slower freezing rate and prolonged storage led to a significant decrease in the proportion of α-helices, and a notable increase in that of β-sheets and random coils. The gluten network was severely deteriorated by a slower freezing rate but was relatively intact in the −40 and −30 °C frozen dough samples. •In this study, −40 °C (0.149 °C/min) freezing was optimum for non-fermented dough.•At the optimal freezing conditions, the dough had better rheological properties.•High freezing rate protects the structural stability of the non-fermented dough.•More disrupted and weak structure were observed in the dough freezing at slow rate.•A slow freezing rate with prolonged storage time obtained the most negative effects.