Quality Optimization and Evaluation of New Cookie Product with Celery Root Powder Addition.

Combined drying, an energy-efficient method that includes osmotic pretreatment in molasses and shortened successive lyophilization, was used to obtain celery root powder and incorporate it in the formulation of cookies, with the aim of obtaining a new product. Wheat flour was substituted with combinedly dehydrated celery root powder at levels from 0 to 30%, and optimization of the amount of wheat flour substitution regarding technological, sensory and nutritive characteristics was performed. The optimal level of 20% substitution was determined using Z-score analysis, from the aspect of the best nutritive improvement and the mildest adverse impact on the technological and sensory quality. In the second research phase, comparison of the cookies with the 20% celery root powder substitution, dehydrated by different methods, indicated that combined dehydration showed upgraded results in terms of the overall quality of the final product, for 28.85 percentile points higher than cookies with lyophilized and for 65.24 percentile points higher than cookies with the addition of convectively dried celery root powder. The cookie containing celery powder previously osmodehydrated in molasses had higher contents of analyzed minerals (1.2-3.3 times), total phenols (10.8%) and antioxidant activities (14% for DPPH and 4% for ABTS) compared to the cookie with lyophilized powder.

Chemical and Thermal Characteristics of PEF-Pretreated Strawberries Dried by Various Methods.

By increasing the permeability of the cell membrane of the treated material, pulsed electric fields (PEF) enhance the internal transport of various chemical substances. Changing the distribution of these components can modify the chemical and thermal properties of the given material. This study aimed to analyze the impact of PEF (1 kV/cm; 1 and 4 kJ/kg) applied to strawberries prior to drying by various methods (convective, infrared-convective, microwave-convective, and vacuum) on the chemical and thermal properties of the obtained dried materials (sugars content, total phenolic content, and antioxidant capacity (ABTS and DPPH assays); thermal properties (TGA and DSC); and molecular composition (FTIR)). PEF could have induced and/or enhanced sucrose inversion because, compared to untreated samples, PEF-pretreated samples were characterized by a lower share of sucrose in the total sugar content but a higher share of glucose and fructose. Reduced exposure to oxygen and decreased drying temperature during vacuum drying led to obtaining dried strawberries with the highest content of antioxidant compounds, which are sensitive to these factors. All PEF-pretreated dried strawberries exhibited a lower glass transition temperature (Tg) than the untreated samples, which confirms the increased mobility of the system after the application of an electric field.

Evaluation of Blue Honeysuckle Berries (Lonicera caerulea L.) Dried at Different Temperatures: Basic Quality, Sensory Attributes, Bioactive Compounds, and In Vitro Antioxidant Activity.

This study aims to comprehensively investigate the effects of hot-air dehydration on the quality of blue honeysuckle berries (Lonicera caerulea L.). The results demonstrated that drying with hot air at 40-65 °C for 7-72 h resulted in blue honeysuckle berries with a moisture content of 0.21-1.10 g H2O/g dry weight. Generally, low to medium temperatures (40-55 °C) showed a better effect on the quality than high temperatures (60-65 °C). Specifically, drying at 40 °C exclusively resulted in better retention of cuticular wax, the best sensory appearance, and the highest total phenolic content. Drying at 45 °C and 50 °C resulted in the highest antioxidant capacity and the optimal sensory flavor. Drying at 55 °C led to the highest soluble solid/acid ratio, ascorbic acid concentration, total flavonoid, and total anthocyanin. The work introduces an innovative raw berry product and provides a comprehensive practical and theoretical framework for convective dehydration of blue honeysuckle berries.

Fundamental drying and agglomeration experiments with bio-fraction and refuse derived fuel for the development of pyrolysis reactor feed.

The EU's circular economy concept necessitates increasing the recycling ratio of municipal solid wastes. There are many existing mechanical-biological processing plants in Hungary for the preparation of residual municipal solid wastes (RMSWs). The two most important products of these plants are the bio-fraction and the refuse derived fuel (RDF). Currently, there are problems with both of these material streams in Hungary, since most of the bio-fraction is still landfilled, and the local thermal utilisation of the RDF has not been implemented yet. The high moisture content of the produced bio-fraction and RDF causes difficulties for the downstream operations; therefore, there is recent engineering interest in drying and agglomeration of these materials. The authors have carried out systematic and parallel drying and briquetting experimental series to study the effect of the material, material composition, mass (volume or surface) of the material, particle size distribution and pre-treatment with a cutting mill on drying intensity in a 1 m3 oven and their effect on briquettability by a laboratory briquette press. The initial slope of the relative moisture loss as function of time was determined. Process engineering design methods of convective hot air-drying can be further developed taking into account the research results. Results can be used for the design of the feed of a pyrolysis reactor once reactor experiments have provided the optimal feed requirements.

Physical and Chemical Properties of Convective- and Microwave-Dried Blackberry Fruits Grown Using Organic Procedures.

This study aimed to evaluate the effect of convective and microwave drying on the bioactive-compounds content of blackberry (Rubus fruticosus) fruits, as well as drying parameters and energy consumption. The fruit was dehydrated in a convective dehydrator at a temperature of 50 °C and 70 °C and in a microwave oven at power levels of 90 W, 180 W and 240 W. The highest amount of anthocyanins, polyphenols and antioxidant capacity were obtained in blackberry fruits that were microwave dried at 90 W and 180 W (46.3-52.5 and 51.8-83.5 mg 100 g-1 dm of total anthocyanins, 296.3-255.8 and 418.4-502.2 mg 100 g-1 dm of total phenolics, and 1.20-1.51 and 1.45-2.35 mmol TE 100 g-1 dm of antioxidant capacity for 90 W and 180 W models, respectively). It turned out that microwave dehydration shortened the processing time and lowered the energy consumption compared to convective drying (a significantly reduced drying time of 92-99% with microwave dehydration). Blackberry fruits dehydrated at 240 W showed the shortest dehydration time (59-67 min), minimal energy consumption (0.23 kWh) and the most efficient diffusion (1.48-1.66 × 10-8 m2 s-1).

Intensification of moisture separation in the pulp convective drying process with ultrasound-assisted method.

Traditional pulp convective drying (CD) is time-consuming and energy-intensive. This study aimed to assess the drying performance of pulp using ultrasound-assisted drying (UAD) and compared it with CD to intensify moisture separation. UAD was found to be fast and efficient with high effective moisture diffusivity of 2.77 × 10-10 âˆ¼ 3.20 × 10-10 m2/s, low activation energy of 20.2 kJ/mol, and short drying time of 21.0 âˆ¼ 16.5 min. It demonstrated that applying ultrasound could promote moisture separation with 26 %∼42 % reductions in drying time and 42 %∼22 % savings in energy consumption. The constant rate period was not presented and no significant differences in drying rates were observed when the moisture ratio was below 0.43 under the investigated conditions. The kinetics modeling results indicated that the Page model was the best to predict the pulp drying kinetics for both methods. It may lead to an alternative efficient approach for decarbonizing the drying process in pulp and paper production.

Microstructural modification of papaya tissue during calcium diffusion: Effects on macrostructure level.

The microstructural changes in papaya tissue during calcium diffusion, the effect on drying kinetics and texture parameters were investigated. Calcium pretreatment was applied to papaya samples for 3 h, at a solution concentration of 1.5 g Ca(OH)2/100 mL H2O, and a solution temperature of 25 °C; subsequently, the samples were convectively dried at 70 °C, air flow of 1.5 m/s, and a relative humidity of 5 ± 2%. Calcium content was determined using the Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) technique, the microstructure of the samples was analyzed by High-Resolution Scanning Electron Microscopy (HR-SEM), and the elementary analysis was performed by Energy-Dispersive X-ray Spectroscopy (EDS). Effective diffusivity of calcium (DefCa) and moisture (Defw) were calculated during pretreatment and drying, respectively and texture parameters were determined by double compression using a texturometer. The transport mechanism determined during calcium pretreatment was diffusion with a DefCa = 3.10 × 10-10 m2/s. Also, branched calcium microstructures in the cell walls of tissue were observed due to the calcium effect, it was supported by elemental analysis, which showed an increase of calcium in section restructured compared to non-restructured. During drying, Defw = 1.86 × 10-9 m2/s was higher in pretreated compared to non-pretreated samples with Defw = 1.17 × 10-9 m2/s, indicating a higher drying rate and moisture loss. The texture values changed significantly (α ≤ 0.05) due to calcium pretreatment and drying; the calcium microstructures caused higher cohesiveness, springiness, gumminess, and chewiness. Calcium modifies the microstructure and composition of papaya tissue; therefore, drying kinetics and texture parameters depend on this modification.

Dehydration study of apple slices by a non-thermal process.

This study investigated the impacts of a drying process under low temperature and reduced pressure (non-thermal drying) on the final dehydrated products characteristics. This process is based on the retention of water on molecular sieves with a good selectivity against these molecules. In this study, drying experiments of 7mm thick apple slices (AS) were performed and compared to apple slices pretreated by freezing. It was concluded that the dehydrated apple slices were depleted of the maximum amount of water after 12 hours of drying, with a final water content equal to 12 ± 1.75%, whereas after freezing pretreatment, a decrease in drying time to 7 hours was observed, as well as a decrease in water content to 10 ± 0.5%. This explains the effect of freezing pretreatment on accelerating water transfer. In addition, a convective drying was performed on the apple slices at 60°C, which allows comparison with the slices dried by our non-thermal drying process. In order to characterize the obtained fruits, characteristic analyses such as water activity (Aw), color, texture (hardness), and dimensions (diameter and thickness) were performed before and after each drying experiment. Thus, continuous measurements of temperature, humidity, and pressure, within the enclosure, were determined during the experiments using a wireless sensor system controlled by a programming Arduino. Finally, mathematical modeling by various models (Newton, Page, Midilli, etc.) was performed to determine the most suitable model describing the non-thermal and convective drying of apple slices.

A Heat and Mass Transfer Model of Peanut Convective Drying Based on a Two-Component Structure.

In order to optimize the convective drying process parameters of peanuts and to provide a theoretical basis for the scientific use of energy in the drying process, this study took single-particle peanuts as the research object and analyzed the heat and mass transfer process during convective drying. In addition, a 3D two-component moisture heat transfer model for peanuts was constructed based on the mass balance and heat balance theorem. Moreover, the changes in the internal temperature and concentration fields of peanut pods during the whole drying process were investigated by simulations using COMSOL Multiphysics. The model was validated by thin-layer drying experiments, compared with the one-component model, and combined with low-field NMR technology to further analyze the internal moisture distribution state of peanut kernel drying process. The results show that both models can effectively simulate the peanut thin-layer drying process, and consistency is found between the experimental and simulated values, with the maximum errors of 10.25%, 9.10%, and 7.60% between the simulated moisture content and the experimental values for the two-component model, peanut shell, and peanut kernel models, respectively. Free water and part of the weakly bound water was the main water lost by peanuts during the drying process, the change in oil content was small, and the bound water content was basically unchanged. The results of the study provide a theoretical basis to accurately predict the moisture content within different components of peanuts and reveal the mechanism of moisture and heat migration during the drying process of peanut pods.

Influence of convective hot air drying on physico-functional, thermo-pasting and antioxidant properties of elephant foot yam powder (Amorphophallus paeoniifolius).

The present study focused on the effect of different drying temperatures (40, 50, 60 and 70 °C) and combination of pre-treatments: potassium metabisulphite (KMS), potassium metabisulphite + Citric acid + blanching (KCB)] on functional, thermo-pasting and antioxidant properties of elephant foot yam (EFY) powder. Drying temperature and pretreatment reduces the water and oil absorption capacity, and the highest values were 2.34 g/g and 1.19 g/g for drying at 40 °C for the untreated sample, respectively. KMS pretreatment enhanced the bulk density, foaming capacity, emulsion capacity, and emulsion stability with an increase in drying temperature. Pasting temperature and viscosity decreased with an increase in drying temperature, and the maximum was observed at 40 °C for KMS pretreatment. Blanching increases the gelatinization temperature resulting in higher mid-and end-temperatures for KCB pretreatment. The antioxidant properties decreased with an increase in the drying temperature and were found to be minimal in the case of KCB treated samples.

Unlocking the Potential of the ANN Optimization in Sweet Potato Varieties Drying Processes.

This study explores the unexploited potential of Artificial Neural Network (ANN) optimization techniques in enhancing different drying methods and their influence on the characteristics of various sweet potato varieties. Focusing on the intricate interplay between drying methods and the unique characteristics of white, pink, orange, and purple sweet potatoes, the presented experimental study indicates the impact of ANN-driven optimization on food-related characteristics such as color, phenols content, biological activities (antioxidant, antimicrobial, anti-hyperglycemic, and anti-inflammatory), chemical, and mineral contents. The results unveil significant variations in drying method efficacy across different sweet potato types, underscoring the need for tailored optimization strategies. Specifically, purple sweet potatoes emerge as robust carriers of phenolic compounds, showcasing superior antioxidant activities. Furthermore, this study reveals the optimized parameters of dried sweet potato, such as total phenols content of 1677.76 mg/100 g and anti-inflammatory activity of 8.93%, anti-hyperglycemic activity of 24.42%. The upgraded antioxidant capability is presented through DPPH●, ABTS●+, RP, and SoA assays with values of 1500.56, 10,083.37, 3130.81, and 22,753.97 µg TE/100 g, respectively. Additionally, the moisture content in the lyophilized sample reached a minimum of 2.97%, holding favorable chemical and mineral contents. The utilization of ANN optimization proves instrumental in interpreting complex interactions and unlocking efficiencies in sweet potato drying processes, thereby contributing valuable insights to food science and technology.

Methods, mechanisms, models and tail gas emissions of convective drying in sludge: A review.

In tandem with the population and economic growth worldwide, the scale of wastewater treatment has been increasing each year. Thus, a large amount of sludge is being produced. If the problem of sludge treatment and disposal cannot be effectively solved, it will cause serious environmental pollution. The premise of sludge drying is that sludge is "harmless" and can be "recycled." Currently, the studies on convective drying focus on the direction of thin-layer drying, fluidized bed drying, spray drying and pneumatic drying. This paper systematically reviews the convective drying technology of sludge. First, the effects of air velocity temperature, relative humidity and particle size on the drying effect are precisely described, as well as the four different drying stages in the drying process, including preheating, constant rate drying, first falling rate drying, and second falling rate drying stages. Second, the research progress of different convective drying treatment technologies and the application of eight mathematical models of thin-layer drying in this field are elaborated. The effects of sludge shrinkage formation mechanisms and sludge viscous resistance generation during the drying process are also discussed in detail. The formation mechanism of sludge shrinkage and the effect of sludge viscosity resistance during drying are also elaborated. Finally, the main dry tail gases and restraining methods are elaborated during the drying process. This paper will provide a structured reference for the related research of sludge convective drying in the future.

Experimental and Numerical Study of a Turbulent Air-Drying Process for an Ellipsoidal Fruit with Volume Changes.

It is common in the numerical simulations for drying of food to suppose that the food does not experience a change of volume. The few numerical studies that include volume changes assume that the shrinkage occurs symmetrically in all directions. Therefore, this effect has not been fully studied, and it is known that not considering it can be detrimental for the accuracy of these simulations. The present study aims to develop a three-dimensional model for the simulation of fruits that includes the volume changes but also takes into consideration the asymmetry of the shrinkage. Physalis peruviana is taken as the subject of study to conduct experiments and imaging analyses that provided data about the drying kinetics and asymmetric shrinkage mode. The effective diffusion coefficient is found to be between 10-12 m2 s-1 and 1.75 × 10-9 m2 s-1. The shrinkage occurs essentially in only one direction, with an average velocity of 8.3 × 10-5 m/min. A numerical modelling scheme is developed that allows including the shrinkage effect in computer simulations. The performance of the model is evaluated by comparison with experimental data, showing that the proposed model decreases more than 4 times the relative error with respect to simulations that do not include volume changes. The proposed model proves to be a useful method that can contribute to more accurate modeling of drying processes.

Effect of intermittent microwave convective drying on physicochemical properties of dragon fruit.

The study was carried out to investigate the effect of Intermittent microwave convective drying (IMCD) on the overall quality of dried dragon fruit in terms of total phenolic content, color change, and rehydration ratio. Three levels of microwave power (200-600 W) and a temperature of 60 °C for hot air were applied alternately throughout the process with three levels of pulse ratio such as 1:10, 1:20, and 1:40, respectively. The total phenolic content of the dragon fruit slice obtained by IMCD was ranged between 5.750 and 6.575 mg GAE/g dry weight. Within the experimental range of process variables under IMCD conditions, the drying efficiency, color change, and rehydration ratio of the dried dragon fruit slices were 15.287-51.930%, 18.643-24.847, and 1.908-3.239, respectively. The Weibull model scale (α) parameter was found to vary between 27.512 - 498.174 , while the shape (ß) parameter was found to vary between 0.769 - 0.851 . The Weibull model parameters were shown to decrease with increasing microwave power at constant pulse ratio. The IMCD method produced a dried dragon fruit slices with reduced color changes and higher total phenolic content and rehydration ratio values. This investigation would contribute to the development of effective drying techniques for increased food quality and product consistency in the drying of diverse fruits and vegetables.

The Modelling of Convective Drying Variables' Effects on the Functional Properties of Sliced Sweet Potatoes.

Drying is a commonly used technology that provides a long post-harvest storage time for produce such as sweet potatoes. Convective drying (CD) is a method that, when conditions are optimized, provides produce with a better appearance and improved textural properties. In this study, changes in water activity (aw), moisture content (MC), rehydration capacity (Rc), shrinkage (Sb) and color attributes were modelled for the optimization of drying factors (temperature, thickness and time) using response surface methodology (RSM). The total phenol content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC) and antioxidant activity of CD samples (63.79 °C, 4.78 h, 3 mm) were investigated as functional aspects and compared with results for FD samples (-45 °C, one term). Optimum convective drying conditions caused an increase in general antioxidant properties, such as total phenol (TPC), total anthocyanin (TAC), DPPH and CUPRAC. The TPC was 190.94 mgGAE/100 g, the DPPH scavenging activity was 12.05%, the TAC was 11.37 mg/100 g, and the CUPRAC was 0.469 mmolTR/g in convectively dried samples under optimum conditions. Although improved appearance and textural properties are obtained by freeze drying, it is possible to produce sweet potatoes with good appearance and functional properties by optimizing the variables of the convective drying process.

Quality retention in pumpkin powder dried by combined microwave-convective drying.

Three distinct drying methods, microwave drying (MWD), convective drying (CVD) and microwave-convective drying (MWCVD) with a grinding process were applied to obtain pumpkin powder. The effects of CVD (60, 70 & 80 °C), MWD (100 & 200 W) and MWCVD (100 W-60 °C, 100 W-70 °C, 100 W-80 °C, 200 W-60 °C, 200 W-70 °C, and 200 W-80 °C) applications on the physicochemical properties (water activity, bulk, tapped & particle densities, porosity, flowability, cohesiveness, swelling capacity, water holding capacity and water solubility index), color values (L * , a * , b * , C, α o and Δe), bioactive compounds (5-Hydroxymethyl-2-furfural (HMF), total phenolic content (TPC) and antioxidant capacity (DPPH and ABTS)) of the eleven pumpkin fruit powders were compared. The MWCVD, namely pumpkin powders dried at 200 W-80 °C resulted in shorter drying times with high-quality dried pumpkin powders. The bulk, tapped and particle densities of pumpkin powders at 200 W-80 °C by MWCVD were 0.56, 0.66 and 1.74 g/cm3, respectively. These values are indicators of the good porosity (61.82%) of pumpkin powders. In addition, the highest TPC (1277.08 mg GA/100 g dw) and ABTS (126.99 ± 3.31 µmol Trolox/g dw) was observed for microwave-convective dried pumpkin powders at 200 W-80 °C. On the other hand, the lowest HMF level (10.12 ± 1.78 mg/kg dw) was found for the pumpkin poowders dried by MWCVD at 200 W-80 °C. In overall, dried pumpkin powders by a MWCVD method can be employed to acquire a high-quality food material along with an enhanced physicochemical properties, color and bioactive components.

Microstructural, biochemical and drying characteristics of dehydrated 'Sunectwentyone' nectarines as affected by sodium metabisulphite.

Abstract: Nectarine fruit is highly perishable due to its high moisture content (89%) and susceptibility to decay. Continuous degradation in quality attributes due to physiological responses and ripening result ultimately in post-harvest losses. Drying of fruit offers the possibility to minimize losses and add value to fresh produce. Thus, this study evaluated the impacts of sodium metabisulphite (SMB; 10 g/kg) and characterized the influence of hot air (50 °C) drying on the kinetics, fruit tissue microstructure, and the physicochemical properties of dried 'Sunectwentyone' nectarines (Super star®). Out of the nine mathematical models, Logarithmic and Henderson, and Pabis models were the most suitable to predict the drying behaviour of sliced nectarines (R 2 = 0.94). Based on the microstructural analysis, prolonged drying led to higher tissue displacement/disruption in dehydrated nectarine slices. Results showed that SMB treatment was more effective in maintaining both the freshness and the color of 'Sunectwentyone' nectarine than the untreated. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01039-6.

Hot air convective drying of hog plum fruit (Spondias mombin): effects of physical and edible-oil-aided chemical pretreatments on drying and quality characteristics.

This aim of this study was to evaluate the effects of pretreatments and temperature on the hot air drying characteristics of hog plum fruits. Hog plum fruits were pretreated with olive oil/K2CO3 or sunflower oil/K2CO3 at 28 °C and olive oil/NaOH cum blanching at 96 °C for 15s, hot water at 96 °C for 15s, and dried in a hot air drier at 50, 60, and 70 °C. Mathematical models were used to fit the data of drying and rehydration kinetics. Results showed that increase in temperature reduced drying time, increased effective diffusivity and shrinkage. Sunflower oil aided chemical pretreated sample had the shortest drying time (780 min) and highest effective diffusivity (6.3 × 10-8 m2/s) at 60 °C, faster rehydration ability at 60 °C, highest retention rate for ascorbic acid (15 %), phenolic content (29 %), and antioxidant activity (12.3 %), while olive oil aided chemical (K2CO3) pretreated sample had the shortest drying time at 50 °C (990 min) and 70 °C (600 min), lowest shrinkage (48.5 %), slower rehydration capacity at 40 °C, and lowest colour change (ΔE = 11.5). Modified Henderson and Pabis and Vega-Gálvez were superior to other fitting models in predicting the drying and rehydration kinetics. Sunflower oil/K2CO3 pretreatment could help improve the drying and quality characteristics of hog plum.

Combining ultrasound, vacuum and/or ethanol as pretreatments to the convective drying of celery slices.

This work studied three emerging approaches to improve the convective drying (50 °C, 0.8 m/s) of celery. Celery slices of 2 mm thick were pretreated for 5 min using ultrasound (32 W/L, 40 kHz), vacuum (75 kPa vacuum pressure) and ethanol (99.8% v/v, as drying accelerator) applied individually or in combination. To evaluate individual effects of ultrasound and vacuum, the treatments were also performed with distilled water or air medium, respectively. Moreover, the cavitational level was characterized in each condition. Drying kinetics was evaluated tending into account the drying time required by each treatment and the Page's model parameters. In addition, microstructural effects and shrinkage were evaluated. As results, ethanol combined with ultrasound significantly improved drying kinetics reducing drying time by around 38%. However, vacuum pretreatment did not affect drying kinetics even in combination with ethanol and/or ultrasound. Microstructural evaluation did not evidence cell disruption, suggesting changes in intercellular spaces, pores and/or cell wall permeability. The use of ethanol and vacuum showed a greater effect on shrinkage after pretreatment and after drying, respectively. In conclusion, at the studied conditions, the drying acceleration by vacuum and ultrasound is lower compared to the effect produced using ethanol.

Development of novel spray-dried and air-dried formulations of Metarhizium robertsii blastospores and their virulence against Dalbulus maidis.

The present research addressed spray-drying and air-drying techniques applied to Metarhizium robertsii blastospores to develop wettable powder (WP) formulations. We investigated the effect of co-formulants on blastospore viability during drying and assessed the wettability and stability of formulations in water. The effect of oxygen-moisture absorbers was studied on the shelf life of these formulations stored at 26 °C and 4 °C for up to 90 days. Additionally, we determined the virulence of the best spray-dried and air-dried formulations against the corn leafhopper Dalbulus maidis. While sucrose and skim milk played an essential role as osmoprotectants in preserving air-dried blastospores, maltodextrin, skim milk, and bentonite were crucial to attain high cell survival during spray drying. The lowest wettability time was achieved with spray-dried formulations containing less Ca-lignin, while charcoal powder amount was positively associated with formulation stability. The addition of oxygen-moisture absorbers inside sealed packages increased from threefold to fourfold the half-life times of air-dried and spray-dried formulations at both storage temperatures. However, the half-life times of all blastospore-based formulations were shorter than 3 months regardless of temperature and packaging system. Spray-dried and air-dried WP formulations were as virulent as fresh blastopores against D. maydis adults sprayed with 5 × 107 blastospores mL-1 that induced 87.8% and 70.6% mortality, respectively. These findings bring innovative advancement for M. robertsii blastospore formulation through spray-drying and underpin the importance of adding protective matrices coupled to oxygen-moisture absorbers to extend cell viability during either cold or non-refrigerated storage. KEY POINTS: • Cost-effective wettable powder formulations of M. robertsii blastospores were developed. • Bioefficacy of formulations against the corn leafhopper was comparable to fresh blastospores. • Cold storage and dual oxygen-moisture absorber are critical for extended shelf life.