This study analyzed the effects of thermal pre-treatments such as convective drying (P-CD), water (BL_W), and microwave blanching (M_BL) and osmotic enrichment pre-treatments with juices from pomegranate (PG), chokeberry (CH), and sea buckthorn (SB) on microwave-vacuum-dried (MVD) carrot properties. Convective drying (CD) and freeze-drying (FD) were used as a comparative method. The dry matter content and water activity of MVD carrots were varied, but in many cases, the values were comparable to those of FD-dried carrots. Pre-enrichment in CH juice significantly reduced the values of the color parameters L*, a*, and b*, regardless of the drying method. The smallest changes were observed in microwave pre-blanching (M_BL). The lowest loss in carotenoid content was observed in CD-dried carrots (14–34 mg/100 g d.m.). Blanching and enrichment in SB juice allowed significant retention of these compounds. As a result of drying carrots, the total phenolic content (TPC) increased. Compared to the raw material, the TPC content in dried carrots increased 3–9 times. Drying using the FD and MVD methods gave a similar effect of increasing the TPC content, including a greater effect after enrichment in CH juice. The highest average antioxidant activity against the DPPH• and ABTS•+ radicals was recorded for FD-dried carrots (6.9 and 30.0 mg Trolox/g d.m.). SB juice contributed to a significant increase in the total vitamin C content, even by 89.1%, compared to raw carrots. Applying osmotic pre-enrichment in PG juice increased the sugar content in dried FD and CD samples by 37.4–49.9%, and in MVD by 21–59%.

The study investigated the effect of osmotic treatment, edible coatings, and reduced pressure on the quality of carrots dried by the microwave–vacuum method (MVD) at 3.5 or 6.5 kPa and microwave power of 250 W. Initial osmotic enrichment (OE) of carrots was carried out in chokeberry NFC juice, and osmotic dehydration (OD) in chokeberry juice concentrate. Coatings were prepared using sodium alginate or citrus pectin solutions of 1.0 or 1.5%. Osmotic treatment, and then drying pressure, had the greatest effect on increasing the dry matter (DM), total phenolic content (TPC), and color changes, but also on decreasing the water activity (AW) of dried carrot. The highest DM (average 98.7%) and the lowest AW (average 0.25) were obtained in OE carrots and dried at 3.5 kPa. Drying carrots, combined with osmotic treatment and coating, increased TPC by 13-fold, from 225 in fresh to 3229 mg GAE/100 g d.m. in dried carrots. Osmotic treatment did not affect the antioxidant activity of DPPH•, but OD significantly increased ABTS•+ compared to the raw material. Coatings had a smaller effect on color changes and antioxidant activity (DPPH• and ABTS•+) and no significant impact on DM and AW. The color changes of the control and coated samples were an increase in color lightness, redness, yellowness, and saturation (vividness), and those subjected to osmotic treatment showed a decrease in these parameters. The lower AW of dried carrots positively affected higher hardness. All samples were sensory accepted, including color, texture, and smell, especially after OD in chokeberry juice concentrate, while crunchiness was the lowest (five out of nine points).

Consumers include pumpkin seeds in their diet as a snack in raw form or minimally processed by roasting. This process enables the seeds to develop a characteristic aroma and color. Herbs and spices are also distinguished by a pleasant and delicate aroma. Among them, marjoram is particularly suited to drying, retaining its flavor better than other dried herbs. Marjoram can be used to impart flavor and aroma to food products and extend their shelf life because it can prevent lipid autoxidation. In this study, pumpkin seeds (Cucurbita pepo) were roasted with and without dried marjoram at 110 and 160 °C for 10 and 30 min, after which the oils were extracted. The results showed that with increasing temperature and roasting time, the moisture content and water activity of pumpkin seeds decreased. Furthermore, roasting pumpkin seeds with marjoram, particularly at 110 °C, enriched their aroma profile with terpenes characteristic of the marjoram aroma. Whether pumpkin seeds were roasted with or without marjoram, the fatty acid composition of the oils obtained was dominated by palmitic, stearic, oleic, and linoleic acids. However, the presence of marjoram during pumpkin seeds roasting resulted in lower peroxide values and specific extinction coefficients K₂₃₂ and K₂₇₀ in the oils obtained compared to their counterparts roasted without this spice. In addition, all the oils showed the ability to scavenge DPPH^· radicals and were characterized by a higher proportion of yellow (positive value of the b* parameter) and green (negative value of the a* parameter) color. In comparison with the oil extracted from unroasted pumpkin seeds, the oil obtained after roasting exhibited a lower chlorophyll and a higher carotenoid content. Thus, roasting pumpkin seeds with spices may enrich their aroma profile with additional components, and the oils obtained may be characterized by better quality parameters.

This study aimed to assess the use of selected raw materials, such as whole-grain oat flakes, pumpkin seeds, sunflower seeds, and flaxseeds, to obtain bars using baking and drying methods. Modifying the bars’ composition involved selecting the fibre preparation, replacing water with NFC juice, and using fresh apple juice and apple pomace. The Psyllium fibre preparation, also in the form of a mixture with apple fibre, was the most useful in dough cohesion and the quality of the bars. Baked bars were characterised by higher sensory quality than those obtained by drying. Microwave–convection drying was a good alternative to baking, primarily due to the lower temperature resulting in a lower acrylamide content and comparable product quality. The basic grain ingredients and fibre preparations mainly shaped the nutritional and energy value and the sensory and microbiological quality. Modifying the recipe using NFC or fresh juice and apple pomace allowed the bars to develop new properties and quality characteristics. The use of NFC juices resulted in a reduction in the pH of the bars, which is associated with a higher microbiological quality of the bars. All bars had low acrylamide content, significantly lower than the permissible level. Using fresh pomace or fibre preparations made from by-products is a possibility to increase the fibre content in the bars and a method of managing by-products.