Agglomeration of turmeric powder and its effect on physico-chemical and microstructural characteristics

Exploring conventional and emerging dehydration technologies for slurry/liquid food matrices and their impact on porosity of powders: A comprehensive review

The contribution of dehydration to the growing market of food powders from slurry/liquid matrices is inevitable. To overcome the challenges posed by conventional drying technologies, several innovative approaches have emerged. However, industrial implementation is limited due to insufficient information on the best-suited drying technologies for targeted products. Therefore, this review aimed to compare various conventional and emerging dehydration technologies (such as active freeze, supercritical, agitated thin-film, and vortex chamber drying) based on their fundamental principles, potential applications, and limitations. Additionally, this article reviewed the effects of drying technologies on porosity, which greatly influence the solubility, rehydration, and stability of powder. The comparison between different drying technologies enables informed decision-making in selecting the appropriate one. It was found that active freeze drying is effective in producing free-flowing powders, unlike conventional freeze drying. Vortex chamber drying could be considered a viable alternative to spray drying, requiring a compact chamber than the large tower needed for spray drying. Freeze-dried, spray freeze-dried, and foam mat-dried powders exhibit higher porosity than spray-dried ones, whereas supercritical drying produces nano-porous interconnected powders. Notably, several factors like glass transition temperature, drying technologies, particle aggregation, agglomeration, and sintering impact powder porosity. However, some binders, such as maltodextrin, sucrose, and lactose, could be applied in controlled agglomeration to enhance powder porosity. Further investigation on the effect of emerging technologies on powder properties and their commercial feasibility is required to discover their potential in liquid drying. Moreover, utilizing clean-label drying ingredients like dietary fibers, derived from agricultural waste, presents promising opportunities.

Application of Central Composite Design and Superimposition Approach for Optimization of Drying Parameters of Pretreated Cassava Flour

The primary goals of this study were to identify the influence of temperature and drying time on pretreated cassava flour, as well as the optimal settings for the factors and to analyze the microstructure of cassava flour. The experiment was designed using the response surface methodology with central composite design and the superimposition approach in order to assess the effect of drying temperature (45.85-74.14 °C) and drying time (3.96-11.03 h) and the optimal drying conditions of the cassava flour investigated. Soaking and blanching were applied as pretreatments to freshly sliced cassava tubers. The value moisture content of cassava flour was between 6.22% and 11.07%, whereas the observed whiteness index in cassava flour ranged from 72.62 to 92.67 in all pretreated cassava flour samples. Through analysis of variance, each drying factor, their interaction, and all squared terms had a substantial impact on moisture content and whiteness index. The optimized values for drying temperature and drying time for each pretreated cassava flour were 70 °C and 10 h, respectively. The microstructure showed a non-gelatinized, relatively homogeneous in size and shape sample with pretreatment soaked in distilled water at room temperature. These study results are relevant to the development of more sustainable cassava flour production.

Frying of the Dispersion Droplets with Varying Contents of Chickpea Flour and Gum Arabic: Product Characterization and Modeling

Dispersions having chickpea (37%, 40%, and 43%, w/w) and gum arabic (0%, 1%, 2%, 3%, 4%, and 5%, w/w) solids were prepared. These dispersion droplets were fried, and the physical, sensory, and microstructural characteristics of the fried products were determined. The oil content in the fried snack decreased up to 20.3% when the level of chickpea and/or gum in the dispersions was increased. The compression curve for fried snack showed 5 major zones and exhibited the failure phenomenon. Failure force (6.5 to 11.4 N) increased with chickpea flour in the dispersions. Fracture strain (12.0% to 19.5%) indicated that all the fried samples were soft-crisp products. An increase in chickpea flour concentration offered an ovoid/oblong shape of dispersion droplets while falling to oil, and changed the spherical shape of the fried snack. The near-spherical product could be obtained by using 37% chickpea flour containing 0 to 2% of gum arabic, or with the 40% and 0 to 1% combinations. The hue or dominant wavelength increased from 578.5 nm (flour) to 581.0 to 582.7 nm (product) indicating a shift toward red coloration. A porous microstructure with scattered small cavities and large vacuoles of the fried snack were observed; big vacuoles were located in the inner portion of the fried product. The cells were divided into closed and open cells and were characterized by image analysis. The air cells usually had an elliptical shape with varying sizes; the cell wall thickness was between 12 and 80 μm. An artificial neural network (ANN) structure of 2-9-2 was developed for the prediction of sensory overall acceptability and oil content of the fried snack.

PRACTICAL APPLICATION

Chickpea flour is used in several food preparations. The addition of gum arabic affects the textural and structural characteristics, and the sensory acceptance; the fried dispersion droplets have a lower fat content when gum arabic is used compared to samples fried without the addition of gum arabic. The fried dispersion droplets change their shape with the level of the ingredients used in the dispersion.