Engineering Texture Properties of Instant Controlled Pressure Drop (DIC) Dried Carrot Chips via Modulating Osmotic Conditions

Abstract

Instant controlled pressure drop (DIC) as a novel drying method can significantly expand the volume of fruit and vegetable chips, resulting in a desirable texture and crispy mouthfeel. Osmotic pretreatment (OP) is an effective processing unit used before DIC to improve the overall qualities of final products. However, the effects of OP on the texture of DIC-dried fruits and vegetables are not fully understood. Thereof, the effects of osmotic treatments on the volume, texture, microstructure, color, and sensory qualities of DIC-dried carrot chips were investigated. The results confirmed that the expanded volume of the DIC-dried samples was highly dependent on solute gain (R2 = 0.9573). According to X-ray microtomographic analysis, the microstructural characteristics of the samples were substantially affected by OP conditions, and the distribution range of pore size was broadened with increasing of osmotic time, while the homogeneity of wall thickness increased with decreasing of osmotic time. Furthermore, sensory evaluation showed that the samples appropriately pretreated (e.g., 60 °Bx for 4 or 6 min) were of great overall quality, and the indicators included hardness, volume, and color, which were significantly correlated with the solute gain (p < 0.01). Overall, the controlled osmotic processing could be used as an excellent pretreatment for modulating the volume expansion and microstructure of DIC-dried carrot chips, thus premeditating the engineering of the texture properties.