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Open sun drying is the predominant process used for food preservation by smallholder and subsistence farmers (SHSFs), and their families, globally constituting about 2 billion people on about 475 million farms. The major problems with this process are the slow, unreliable speed of completion, rain-caused loss of vital food sources, risks from mycotoxin accumulation, environmental contamination, and loss of nutritional quality. SHSFs represent the poorest and least educated human demographic, whose survival is largely ignored by Governments, untouched by international aid programs, and with limited access to basic utilities. Solar drying systems can greatly improve the preservation of safe and nutritious food, but current systems deployed put this technology beyond the reach of the demographic which needs it most. Here, our objective was to develop the technology for the simplest low-cost drying system, which would minimize all risk factors, particularly eliminate mycotoxin accumulation, and which could be practically deployed by SHSFs. [ABSTRACT FROM AUTHOR]

Starchy staples are the main source of energy for most of the global population, and future growing populations and limited arable land areas dictate that reducing post-harvest losses of produce and conserving energy consumption are critical. With the increased prevalence of chronic non-communicable diseases (such as cardiovascular disease) and the implementation of the Sustainable Development Goals, the benefits of grains for human health are being rethought. Drying, as a significant and energy-intensive unit operation in post-harvest handling and storage of grain, has been extensively studied by scholars. This paper describes several common types of starchy staple foods and their drying and pretreatment technologies in recent years, focusing on some auxiliary drying technologies to improve drying efficiency and energy-saving aspects, while pretreatment technologies not only improve drying efficiency but also help to retain nutrient content. And with the increasing pursuit of nutrition, personalized food is essential in the future. This paper also introduces the application prospects of starchy staples, including 3D printing, the aerospace field, and special medical food. [ABSTRACT FROM AUTHOR]

To respond to the various issues of conventional drying (textural defects of collapse-shrinkage and case hardening, microbiological contamination, poor rehydrability, degradation of active molecules caused by high wet-bulb temperature, weak drying kinetics, and marketing difficulty), swell-drying has proven high relevance in combining conventional drying processes with the Instant Controlled Pressure Drop (D.I.C.). The international team of "Research & Engineering Platform for intensifying Drying Processes (REPID)" has studied phenomenological models and experimental trials combining D.I.C. with new Interval Hyper-Active Drying (IHAD) processes. Currently, IHAD includes interval starting accessibility drying (ISAD), interval infrared airflow drying (IIRAD), and interval microwave airflow drying (IMAD). All these "interval operations" are sandwiched into cycles, each comprising double separate independent mechanisms; a short, hyper-focused active period (that generates and sweeps out vapor to the surrounding environment) alternated by a passive period of internal water diffusion/moisture homogenization. Since surface evaporation is highly intensive, the wet-bulb temperature stays low, although highly effective drying kinetics. Thus, the operation results in avoiding biochemical damage risks. Coupled with the D.I.C. texturing-decontamination, these drying operations are very effective in terms of drying kinetics, energy consumption, and product quality of heat-sensitive solids. It has led to the manufacturing of effective drying equipment. [ABSTRACT FROM AUTHOR]

Although people's perception of fruits and vegetables is green, healthy and nutritious, the consumption of fruits and vegetables for most people around world still does not meet the WHO's recommendations for a healthy diet. Functional foods and beverages containing functional ingredients with health-improving properties, are gaining increasing popularity among consumers and the food industry. Either hydrous or dried fruit and vegetables formulated into beverages can promote the daily intake and is a splendid delivery approach for nutrients and bioactive compounds to human body. Drying is the good method to preserve fruit and vegetables characterized by high moisture content and perishability. However conventional drying processes are strongly associated with high temperature, which is detrimental to their nutritional and sensory qualities. This work aims to review low temperature drying technologies for fruits and vegetables to better maintain the qualities and expand their application in functional beverages. [ABSTRACT FROM AUTHOR]

The present study was undertaken to determine the effect of natural colorants and combination with select chemical products on anthocyanins, total phenolics (TPC) and total flavonoids content (TFC) of rose powder, and on the stability of anthocyanins (ACNs) during storage. Moreover, the color property of rose juice in holding period of 0-1hr at room temperature was also studied. Rose powder was mixed with three chemicals (citric CA; ascorbic AA; tartaric acid TTA) and natural colorants powder (Anthocyanin; Hibiscus; food-grade Vitamin-C) at different levels viz. 0.1%, 1%, 5% and 10% (w/w), respectively. AA addition at 1% retained the highest anthocyanins content among the chemical groups, while Hibiscus 1% addition resulted in the highest amount of anthocyanins retention (56.02 ± 1.86 mg/g, cyanidin 3- glucoside equivalent). In addition, the degradation rate of anthocyanins increased significantly with storage time and temperature except for 1% Hibiscus flowers at 25 °C. TPC of chemical additions showed no significant change in rose powder. However, natural colorant additions resulted in distinct TPC and TFC compared to the control sample except for Vitamin-C addition. All the additive-mixed samples exhibited a lighter color and lowered the redness value after a period of time. [ABSTRACT FROM AUTHOR]

The growing awareness of the health benefits of edible roses has attracted researchers to explore different rose products. In this study, fresh roses were dried using different techniques including vacuum freeze, hot air, heat pump, relative humidity and catalytic infrared drying. The influence of drying techniques on rehydration kinetics and quality attributes were evaluated. Results showed that the Weibull model provided the best fitting for each rehydration curve. Total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC) and antioxidant activity of rose infusion increased while the sensory score decreased with brewing time increasing. Amongst dried products, vacuum freeze drying combined with 5 min brewing had higher TPC (33.97 ± 0.83 mg GAE/g DW), TFC (13.77 ± 0.26 mg RE/g DW), TAC (8.81 ± 0.20 mg CGE/g DW), and antioxidant activity (DPPH IC50: 1.36 ± 0.03 mg/mL and ABTS IC50: 1.16 ± 0.05 mg/mL) along with the highest evaluation score (8.54). The present findings will offer more information in selecting the best drying technique for rose brewing as a tea beverage. [ABSTRACT FROM AUTHOR]

Since sludge mitigation requires new strategies for enhanced dewaterablity, several scientific and technological advancements in conditioning, dewatering and drying technologies for a variety of sludges are being developed continuously. Grappling with the problem of ever-increasing sludge volume, it is important to critically assess the new concepts to assist in rapid technological developments in this area. This paper provides a concise state-of-the-art discussion focused on the effects of the key parameters including affected dewatering performance according to the sludge type, source and its physicochemical characteristics, rheological factors, particle size distribution, floc surface charge and endogenic polymeric substances (EPS), on the dewatering performance. Since initial conditioning is highly critical on the following dewatering and drying steps, innovative methods, e.g., physical conditioning, sonication, hydrodynamic cavitation, thermal treatment, microwave, electrical treatment, photocatalytic treatment and chemical coagulation/flocculation have been included in this review. Furthermore, latest developments in dewatering and drying technologies are also discussed in terms of their advantages/disadvantages and energy demands. This paper includes a capsule discussion of control of industrial sludges and the application of advanced oxidation processes (AOP(s)) in sludge conditioning and dewatering. [ABSTRACT FROM AUTHOR]

To mitigate encrustation of beef jerky and improve quality during hot-air impingement roast drying (HIRD) process, the effect of different relative humidity (RH) conditions (NO (about 2.3%), 10%, 15%, 20%) at a constant roast drying temperature of 120 °C on "encrustation" thickness, cooking yield, microstructure, tenderness, color, myoglobin, lipid oxidation, flavor and sensory quality of beef jerky were explored. Results indicate that improving RH decreased the "encrustation" thickness of beef jerky significantly (p < 0.05) as the moisture distributed more evenly shown by magnetic resonance imaging analysis. Microstructure observation showed that the number of gaps between muscle bundles decreased and muscle bundles become plumper at both cores and edges of beef jerky with an increase of RH. Meanwhile, humidification could improve the color quality of beef jerky, decline the content of malondialdehyde (MDA) as well as enhance the flavor of beef jerky. The findings in this work indicate that humidification enhances the quality of beef jerky by alleviating surface encrustation, improving color, reducing lipid oxidation, and enhancing roast drying flavor during HIRD processing. [ABSTRACT FROM AUTHOR]

Fresh foods such as fruits, vegetables, grains, nuts, and meats are generally rich in water and are susceptible to microbial contamination. Drying and dehydration processes can reduce water content, but low water activity foods may not be microbiologically safe. Several novel drying techniques have demonstrated varying degrees of effectiveness in microbial inactivation, including supercritical CO2 drying, low-pressure superheated steam drying, microwave drying, radio frequency drying, infrared drying, vacuum drying, freeze drying, etc. Some typical microorganisms used as indicators of microbial inactivation including natural present microorganisms (e.g., mesophilic bacteria and their spores, yeast and mold) and various pathogens (e.g., Escherichia coli O157:H7, Listeria monocytogenes and Salmonella spp.). This paper reviewed novel drying techniques for controlling microbial contamination of fresh foods and analyzed their advantages/disadvantages and microbial inactivation capabilities. These novel drying techniques have the potential to ensure microbiological safety during drying and have the prospect of shortening the food processing chain by integrating drying and sterilization/decontamination into the same process. [ABSTRACT FROM AUTHOR]

Presence of pesticide residues on fruits and vegetables is a serious safety issue for consumers. Efforts are being made to utilize drying technology to turn fruits and vegetables with high pesticide residues into dehydrated products with minimal or no pesticide residues are clearly conducive to ensuring safety and international fresh food commodity trade. This paper attempts to summarize the latest developments in drying technologies and pre-drying treatments for controlling pesticide residues in fruits and vegetables, with emphasis on sun-, oven-, freezing-, vacuum-, and microwave-drying technology, as well as non-thermal pretreatment methods such as ultrasound, non-thermal plasma (NTP), pulsed electric field (PEF), high hydrostatic pressure (HHP), and irradiation. [ABSTRACT FROM AUTHOR]

The increased use of vacuum microwave drying in food industry is attributed to shorter drying time and lower temperature. The temperature change of materials is difficult to model due to the vacuum condition. A simplified mathematical model is presented subject to some assumptions to predict the temperature distribution in slices made using a mixture of potato and apple purées. Dielectric loss factors of mixed slices were found to increase with temperature and water content. The model accounts for temperature and moisture-dependent dielectric loss factor which yields a useful predictive tool. [ABSTRACT FROM AUTHOR]

To improve the quality of freeze-dried dumplings, a novel hybrid strategy that different cooking methods combined with chitosan coating were applied in the preparation of dumplings. The dumplings, obtained according to the formula, first treated by three different cooking methods (microwave, boiling, and steaming), respectively, and then coated with chitosan with a mass fraction of 1.5%. The dumplings without coating treatment was used as control group. Results showed that, the drying time of steamed dumplings was the shortest (720 min), but its whiteness and rehydration performance were unacceptable to consumers. The whiteness of boiled dumplings was the highest, but its drying time was 90 min longer than that of steamed dumplings. The freeze-dried dumplings pretreated by microwave cooking had the best rehydration performance (rehydration rate, cracking rate of rehydrated dumplings, and rehydration loss rate) and hardness. Chitosan coating treatment of cooked dumplings was been found to have a satisfactory positive effect on inhibiting the cracking rate of freeze-dried dumplings, the cracking rate of rehydrated dumplings and the rehydration loss rate of freeze-dried dumplings. Microwave cooking combined with chitosan coating was considered to be the most suitable hybrid strategy for the production of high-quality freeze-dried dumplings. [ABSTRACT FROM AUTHOR]

Due to the fast pace of life around the globe and the increasing demand for high-quality convenience foods by consumers, instant foods have attracted widespread attention. By adjusting the process and formula, the quality of compound formula foods can be optimized. Drying is a common way. However, conventional drying methods have some shortcomings. Freeze drying can overcome most of them. Foam mat freeze-drying can increase the drying area of materials, and the drying efficiency of it is also higher. For thermal-sensitive materials, it is a suitable drying method. Microwave freeze drying, infrared drying, and others are relatively new processing technologies that are suitable for the production of instant foods. This paper provides an overview of recent developments in processing technologies for the production of compound formula instant foods. [ABSTRACT FROM AUTHOR]