Process optimization of CO₂ high-pressure and low-temperature explosion puffing drying for apple chips using response surface methodology

Abstract

The product could not be effectively expanded and the puffing temperature was too high, which usually occurred during the explosion puffing drying process of fruits and vegetables. CO₂ high-pressure and low-temperature explosion puffing drying technology was investigated as potential means for the production of apple snack food. The samples were pre-dried with hot air to a moisture content of 15% to 20% (w.b.). The process factors including puffing pressure difference (0.86–1.54 MPa), puffing temperature (53–87 °C), and vacuum drying time (28–62 min) were investigated using response surface methodology with central composite design. The optimum CO₂ high-pressure and low-temperature explosion puffing drying conditions were puffing pressure difference, puffing temperature, and vacuum drying time of 1.25 MPa, 74 °C, and 33 min, respectively. At this optimal condition, expansion ratio, rehydration ratio, and crispness were found to be 1.7, 2.23 g/g, and 29.3, respectively. Apple crisps obtained under optimal processing conditions have a highly porous structure from SEM micrographs.

KEYWORDS:

• CO₂
• apple
• response surface methodology
• explosion puffing drying

Additional information

Funding

This work was supported by the National Key R&D Program of China [2017YFD0400902-1], the National Natural Science Foundation of China [51876109, 21808135], the Key Project of International Science and Technology Cooperation Program for Shaanxi Province [2020KWZ-015], and the Key Research and Development Program of Shaanxi Province [2017KW-001].