Whole grain flour is gaining increasing popularity in the international community as a key component of a healthy diet, with whole highland barley flour (WHBF) particularly favored for its rich nutritional value. Despite its nutritional benefits, concerns have arisen due to the frequent occurrence of microbial contamination cases in powdered foods, prompting a heightened societal awareness. Consequently, the microbial inactivation treatment of grain flour has become pivotal in guaranteeing both the quality and safety of the edible product.

The Food Nutrition and Functional Food Innovation team of Institute of Food Science and Technology (IFST) of CAAS has successfully and independently developed the continuous instant pressure drop (CIPD) sterilizer, which could effectively reduce total bacterial counts of 3.8 log cfu/g in the WHBF in 22 seconds. In this study, the effects of CIPD treatment on the microstructure, rheological properties, and flavor characteristics of WHBF were further discussed, and the above items of CIPD-treated WHBF were compared with those after ultraviolet-C (UV-C), ozone and hot air (HA) treatments.

The results showed that the increase of damaged starch content of CIPD-treated WHBF led to the roughness and partial aggregation of starch particles and the increase of particle size, causing the pasting temperature and viscosity were obviously improved. Compared with UV-C, ozone and HA treatments, the CIPD-treated WHBF showed higher storage modulus and loss modulus, and better gel strength. The relative crystallinity of WHBF was changed by UV treatment, and the protein secondary structure of WHBF was changed by ozone treatment. As for the flavor characteristics, CIPD treatment could maintain the original flavor of WHBF better than conventional HA treatment. The above findings provided a basis for the application of CIPD technology in powdery foods industry.

The above research was published in the JCR Q1 journal Food Research International (IF: 8.1). Chen Zhiying is the first author of the paper, Prof. Wang Fengzhong and Prof. Tong Litao are the co-corresponding authors. The work was funded by Special National Key Research and Development Plan (2021YFD1600101) and Key Science and Technology Project of Qinghai Province (2021-0101NCC-0001).

Link to the paper:

https://doi.org/10.1016/j.foodres.2023.113408

Figure 1 Graphical abstract