Aleksandra Zimmer

The study focused on utilizing post-process osmotic solution enriched with inulin or maltodextrin, evaluating its potential for spray drying. Parameters such as yield, energy consumption, and the physical properties of the dried solutions and powders—including moisture content (Mc), water activity (Aw), color, true and bulk density, porosity, and glass transition temperature—were analyzed. The effects of carrier type, concentration, and inlet temperature (Tin) were systematically examined. Samples dried with maltodextrin demonstrated over 50% higher yield than those with inulin, with a highest yield of 32.13 ± 0.64% (with maltodextrin) and a lowest yield of 2.75 ± 0.48% (with inulin). Higher Tin improved drying efficiency by reducing Mc but also caused darker powders. Energy consumption increased with rising Tin, peaking at 2295 ± 51 kJ. The Spray Drying Energy Index (SDEI) was introduced to assess energy consumption relative to powder yield, with the most favorable SDEI values observed for processes with the highest total energy consumption. These same samples exhibited lower Mc and Aw values. The lowest bulk density was 0.455 ± 0.004 g·cm⁻³, while porosity was 58.3 ± 0.7%. The results highlight the potential of spray drying as a sustainable method for utilizing by-products from osmotic dehydration, aligning with the principles of sustainable food practices.

The study focused on utilizing post-process osmotic solution enriched with inulin or maltodextrin, evaluating its potential for spray drying. Parameters such as yield, energy consumption, and the physical properties of the dried solutions and powders—including moisture content (Mc), water activity (Aw), color, true and bulk density, porosity, and glass transition temperature—were analyzed. The effects of carrier type, concentration, and inlet temperature (Tin) were systematically examined. Samples dried with maltodextrin demonstrated over 50% higher yield than those with inulin, with the highest yield of 32.13±0.64% and the lowest yield of 2.75±0.48%. Higher Tin improved drying efficiency by reducing Mc but also caused darker powders. Energy consumption increased with rising Tin, peaking at 2295±51 kJ. The Spray Drying Energy Index (SDEI) was introduced to assess energy consumption relative to powder yield, with the most favorable SDEI values observed for processes with the highest total energy consumption. These same samples exhibited lower Mc and Aw values. The lowest bulk density was 0.455±0.004 g·cm-3, while porosity was 58.3±0.7%. The results highlight the potential of spray drying as a sustainable method for utilizing by-products from osmotic dehydration, aligning with the principles of sustainable food practices.

This study investigates the effects of osmotic dehydration on garlic clove halves using a low-pH osmotic solution with ascorbic acid, concentrated tomato juice, and basil extract (45° Brix). Samples, both dehydrated and fresh, were subjected to various drying methods. Physical properties, such as CT scan analysis, texture profile analysis (TPA), porosity, and density, were examined. Additional parameters like energy consumption, specific energy consumption, moisture content, water activity, and color change were evaluated. Osmotic dehydration reduced moisture content by over 7.5%. The specific energy consumption for microwave vacuum drying (MVD) was 95 kJ/g for osmotically dehydrated samples compared to 118 kJ/g for non-dehydrated samples. Drying times decreased by 24 min for MVD and 15% for microwave convective drying (MCD). The Weibull model best fit the drying kinetics, with R² values above 0.99 and RMSE below 0.03 for all methods. TPA tests showed no significant impact of osmotic dehydration on hardness, though drying methods significantly affected hardness, ranging from 49 N to 707 N. Color change was higher for osmotically dehydrated samples, reaching 37.09 for OD-CD compared to 29.78 for CD.

Flowers of hemp (Cannabis sativa L.) are widely used in cosmetics, food, and in the pharmaceutical industry. The drying process plays a key role in retention of aroma and also in the quality of products. Seven variants of hemp flower drying, including convection drying (CD), vacuum–microwave drying (VMD), and combined drying consisting of convective pre-drying followed by vacuum–microwave finishing drying (CPD-VMFD) were checked in this study. For each process, we applied the two-term model. Dried material was submitted to color and chromatographical assessments. Analyses of obtained essential oil showed the presence of 93 volatile compounds, predominantly β-myrcene, limonene, and β-(E)-caryophyllene, as well as α-humulene. Application of 240 W during VMD and 50 °C during CD gave the highest retention of aroma compounds, amounting to 85 and 76%, respectively, but with huge color changes. Additionally, sensory analysis proved that drying with a microwave power of 240 W provides a product most similar to fresh material.

The effect of different drying techniques (freeze, convective, vacuum-microwave and combined drying) on the drying kinetics, the phytochemical compounds and sensory characteristics in loquat cultivar ‘Algar’ was studied. The convective drying resulted in the highest amount of total hydroxycinnamic acids (5077 mg/kg wet weight (ww)), with 3-caffeoyl quinic acid and 5-caffeoyl quinic acid being the greatest carotenoids. The highest values of total carotenoids were obtained by the freeze-drying technique (2601 mg/kg ww), followed by all convective treatments and vacuum-microwave at 360 W. The highest carotenoid was β-carotene. The ABTS^+• (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (Ferric Ion Reducing Antioxidant Power) values ranged from 2.04 up to 3.27 mmol Trolox/100 g ww, and from 1.89 up to 2.29 mmol Trolox/100 g ww, respectively. As expected, the color difference of freeze-dried samples was the lowest (7.06), similar to combined drying conditions (9.63), whilst the highest value was found after convective drying (37.0). All treatments were sensory acceptable (no off-flavors). However, still, further research is needed to fully optimize these studied drying treatments because the freeze-dried sample still had higher carotenoid content and better instrumental color parameters. Although recently the impact of microwave drying has been studied, this is the first work comparing phytochemical composition of loquat fruit under the different drying methods mentioned above.