Response Surface Optimization of Solar Drying Conditions and the Effect on the Quality Attributes and Drying Characteristics of Qula Casein

Jun Wang; Lina Wang; Linlin Wang; Ling Han; Lianhong Chen; Shanhu Tang; Pengcheng Wen

doi:10.3390/foods11162406

Response Surface Optimization of Solar Drying Conditions and the Effect on the Quality Attributes and Drying Characteristics of Qula Casein

Foods. 2022 Aug 10;11(16):2406. doi: 10.3390/foods11162406.

Authors

Jun Wang^{1

2}, Lina Wang¹, Linlin Wang¹, Ling Han³, Lianhong Chen¹, Shanhu Tang¹, Pengcheng Wen³

Affiliations

¹ College of Food Science and Technology, Southwest Minzu University, Chengdu 610041, China.
² College of Food Science and Engineering, Northwest A&F University, Xianyang 712100, China.
³ College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China.

Abstract

The objective of this study was to investigate the potential application of a mixed-mode solar dryer to Qula dehydration in the Qinghai-Tibet Plateau of China. A three-factor five-level central composite rotatable design (CCD) of the response surface methodology (RSM) was employed to evaluate the influences of drying process variables on quality attributes in terms of lipid oxidation [peroxide (POV) and thiobarbituric acid reactive substance (TBARS)] and Maillard reaction (5-hydroxymethylfurfural, 5-HMF). The impact of drying temperature (30−50 °C), material thickness (5−15 mm), and wind velocity (0.4−1.4 m/s) on the color, POV, TBARS, and 5-HMF of Qula were studied. Optimum operating conditions were found to be a temperature of 43.0 °C, material thickness of 11.0 mm, and wind velocity of 1.0 m/s based on the minimum of POV, TBARS, and 5-HMF. In this condition, the values of POV, TBARS, and 5-HMF were 0.65 meq/kg, 0.516 mg/kg, and 4.586 mg water/L, respectively, which are significantly lower than for drying of Qula by open sun-drying (p < 0.05). Compared with open sun-drying, the drying time of Qula by solar drying was shortened by 61.5%. The results indicate that the mixed-mode solar dryer is a feasibility drying technology for Qula and could effectively improve the quality of products.

Keywords: Qula; drying characteristics; lipid oxidation; response surface methodology; solar drying.

Grants and funding

This research was funded by the basic scientific research operating expenses of the central universities (No. 2021XJTD02); The National Natural Science Foundation of China (No. 32001726); The National key research and development program, Integrated demonstration of coordinated development technology of yak grazing in alpine pastoral areas (No. 2021YFD1600205).