Substantiation of the Energy Efficient Schedules of Drying Grain Seeds

It is important to study the patterns of drying grain seeds in order to improve the energy efficiency of the process. Energy efficiency is one of the main parameters that define the choice of a drying schedule. Traditional drying technologies are based on low temperature schedules, which do not allow significantly intensifying the process by increasing the temperature of the heat agent because of substantial reductions in the quality of the material. To adequately assess the drying schedules, we conducted the study of drying grain seeds at low temperatures aimed to preserve the seed properties of the material. To increase the energy efficiency of the drying process, a step-by-step descending low-temperature drying schedule was suggested, which provides for the required quality of seed material. All the proposed technical solutions for the energy-efficient schedules of drying grain seeds were summarized in the recommendations for industrial drying in column type direct-flow grain dryers.

Application of Blue Honeysuckle Powder Obtained by an Innovative Method of Low-Temperature Drying in Skincare Face Masks

Traditional technologies applied for obtaining plant raw materials for cosmetic production are based primarily on high-level processing, which is reflected in the qualitative composition of the resulting materials. By using low-temperature drying, it is possible to retain in the raw materials a range of valuable ingredients. In this study, blue honeysuckle powder was used as an ingredient of cosmetic face masks. The stability of the masks was evaluated. Dynamic viscosity, yield point and texture analysis of the cosmetics was performed. The color of the emulsions and the level of skin hydration after face mask application was determined. Emulsions were found to be stable. A decrease in dynamic viscosity of the emulsions as a function of increasing concentrations of the additive and under the conditions of rising rotational speed were observed. Similarly, an increase in the concentration of blue honeysuckle in the emulsions resulted in a decrease in the value of the yield point. Based on the results, it can be stated that the addition of blue honeysuckle caused a decrease in hardness of the masks, while the opposite trend was observed for adhesive force. It was found that an increase in the concentration of blue honeysuckle gave a reddish-yellow color to the samples. Corneometric assessment confirmed proper skin hydration after the application of the emulsions.

Coupling electro-dewatering and low-temperature air-drying for efficient dewatering of sludge

This study investigated the effects of electro-dewatering on subsequent low-temperature drying at various potentials and the characteristics of low-temperature air-drying sludge were explored through experiments and multi-physical modeling. Experimental results showed that the extracellular polymeric substance (EPS) content in the sludge was reduced during electro-dewatering process, even the species of organic matter was changed, as well as the dewatered cake tend to form many seepage channels, crack and a certain number of holes. These changes in the properties and structure were conducive to the subsequent low-temperature drying process. For air-drying process, the mass of the sludge cake variation was simulated and results were consistent with the experimental phenomenon. Firstly, the weight of the sludge cake was decreased approximately linearly with time, then tended to stable and reached the dewatering limitation finally. The applied higher electric field intensity (25 V cm−1) in the front-end electro-dewatering were conducive to promote water vapor diffusion activity in air-drying stage. Energy consumption and yield analysis results indicated that the combined technology has lower energy consumption and higher yield than that of directly low-temperature drying.

Viability of Lactobacillus plantarum TISTR 2083 in Protectant during Low-Temperature Drying and Storage

Low-temperature drying was applied as simple and low cost drying technique for the production of dried Lactobacillus plantarum TISTR 2083, which was isolated from traditional starter of Ka-nom Tuay-fu. To improve the survival of L. plantarum TISTR 2083 during drying and storage, five different protectants and two carrier materials were investigated. These include sucrose, trehalose, maltodextrin, skim milk, and L-glutamate sodium salt (L-GSS) as protectant and rice starch and rice flour as carrier material. Whereas, skim milk as protectant with rice starch resulted in higher viable cell (8.71 log CFU/g) after drying by hot air oven at 40 °C. Different concentration 5, 10, and 15% (w/v) skim milk also investigated to check the effect of skim milk concentration on cell viability. L. plantarum TISTR 2083 starter powder was in different storage conditions to check the storage stability. After 90 days of storage, starter powder stored at 4 °C with silica gel and without silica gel had more than 80% survival rate, while there was no viable cell that stored in room temperature with silica gel. The result showed the production and storage conditions of high viability L. plantarum TISTR 2083, which can be used as starter culture for further fermented product development and as probiotic.

Ginger (Zingiber officinale) powder from low temperature drying technique

Ginger powder was prepared using different low temperature drying techniques and their nutritional, phytochemicals, functional and sensory quality were investigated. Moisture content was significantly (p<0.05) higher (7.16±0.04%) in shade dried powder and lowest in oven dried powder. Protein, fat and fiber contents varied with drying techniques ranging from 6.08±0.05 to 6.68±0.07%, 1.08±0.16 to 1.39±0.25% and 3.86±0.13 to 5.11±0.06% respectively. Highest alkaloid content was found in mechanical dried powder (4.44±0.04%), while highest flavonoid content was found in oven dried ginger powder (4.67±0.07%) and maximum saponin content was recorded in shade dried powder (2.67±0.10%). Highest ascorbic acid content (3.53±0.08 mg/100g) was found in shade dried powder and lowest was recorded in oven dried ginger powder (3.53±0.08 mg/100g). Sun drying technique exhibited better nutritional and sensory quality. The sensory score demonstrated that acceptance of all dried ginger powder was in the range of liked very much to liked moderately by the panelist. Low temperature drying techniques have positive significance on retaining phytochemicals and sensory quality of processed ginger. Bangladesh J. Sci. Ind. Res.56(2), 133-140, 2021

Combined Use of Solar and Biomass Energy for Sustainable and Cost-Effective Low-Temperature Drying of Food Processing Residues on Industrial-Scale

In this study, a low-temperature drying plant based on renewable energies to dry food processing wastes is investigated. The demand-oriented heat supply is realized by a solar wall in combination with a biomass boiler. Due to the operational complexity of such a system with different sub-units and process parameters, steady-state simulations were performed in Aspen Plus to provide an insight into the process. Moreover, a time-resolved energetic evaluation was conducted to analyze the influence of varying capacity of the heat sources and operational strategy in addition to economic calculations. The simulations showed that an overall control strategy needs to consider the air properties as well as the flow rate of wet input material. In the reference case, the boiler must be operated at full load through the year to supply as much heat as possible. The revenue from the dried material was the most crucial parameter on the drying economics. Although the current plant configuration operating at 12 h per day and five days per week enable feasible results, the drying process can be more profitable by doubling the boiler capacity and increasing operational hours to 24 h per day and five days per week. The proposed plant can provide an environmentally friendly and cost-effective solution for the re-valorization of food-processing wastes into added-value compounds.