Vacuum impregnation and drying of calcium-fortified pineapple snacks

Recent advances in vacuum impregnation of fruits and vegetables processing: A concise review

Vacuum impregnation (VI) is a novel, non-thermal treatment that aims to modify the composition of food material by partially removing water and air and impregnating it with physiologically active compounds without affecting the structural integrity of food matrix. Application of VI accelerates the mass transfer processes, which leads to few changes in food composition and improves dehydration. Large volumes in intracellular spaces of fruit and vegetable tissues make it suitable to introduce different agents like nutrients, cryoprotectants, browning inhibitors, enzymes, and chemicals; enhancing texture profile and inhibiting tissue softening, or compounds lowering water activity and pH. water activity Thus, the VI may help to achieve new product quality associated with physicochemical features and sensory attributes. This review highlights the evolution and mechanism of VI technique, major factors affecting VI of fruits and vegetables and their responses to processing, and industrial relevance. Vacuum impregnation consists ability to revolutionize various aspects of food processing and preservation. VI serves as a versatile tool that enhances the quality, shelf life, and nutritional content of processed fruits and vegetables. It offers unique advantages of altering product composition by introducing desired compounds while preserving structural integrity. VI improves mass transfer processes, reduces water content, enhances the absorption of nutrients, antioxidants, and preservatives. This technology finds application in producing fortified foods, extending shelf life, and creating innovative products with improved sensory attributes. VI's ability to efficiently impregnate substances into porous materials, combined with its energy-saving potential and compatibility with other processing methods, makes it a valuable tool in the food industry. As consumers demand healthier and long-lasting products, VI emerges as a promising solution for meeting market demands.

Lipid incorporated biopolymer based edible films and coatings in food packaging: A review

In the evolving landscape of food packaging, lipid-based edible films and coatings are emerging as a sustainable and effective solution for enhancing food quality and prolonging shelf life. This critical review aims to offer a comprehensive overview of the functional properties, roles, and fabrication techniques associated with lipid-based materials in food packaging. It explores the unique advantages of lipids, including waxes, resins, and fatty acids, in providing effective water vapor, gas, and microbial barriers. When integrated with other biopolymers, such as proteins and polysaccharides, lipid-based composite films demonstrate superior thermal, mechanical, and barrier properties. The review also covers the application of these innovative coatings in preserving a wide range of fruits and vegetables, highlighting their role in reducing moisture loss, controlling respiration rates, and maintaining firmness. Furthermore, the safety aspects of lipid-based coatings are discussed to address consumer and regulatory concerns.

Optimization and modeling of vacuum impregnation of pineapple rings and comparison with osmotic dehydration

The vacuum impregnation (VI) process parameters (vacuum pressure = 20-60 kPa; VI temperature = 35-55°C; concentration of the sucrose solution = 40-60 °Brix; and vacuum process time = 8-24 min) for pineapple rings were optimized based on the moisture content (MC), water loss (WL), solids gain (SG), yellowness index (YI), and total soluble solids (TSS) content of pineapple rings using response surface methodology (RSM). A relationship was developed between the process and response variables using RSM and artificial neural network (ANN) techniques. The effectiveness of VI was evaluated by comparing it with the osmotic dehydration (OD) technique. The optimum condition was found to be 31.782 kPa vacuum pressure, 50.441°C solution temperature, and 60 °Brix sucrose concentration for 20.068 min to attain maximum TSS, YI, SG, and WL, and minimum MC of pineapple rings. The R2 values of RSM models for all variables varied between 0.70 and 0.91, whereas mean square error values varied between 0.76 and 71.58 and for ANN models varied between 0.87-0.93 and 0.53-193.78, respectively. Scanning electron micrographs (SEM) revealed that parenchymal cell rupture was less in VI than in OD. The VI pineapple rings exhibited more pores and high SG, as compared to OD, due to the pressure impregnation. Spectroscopic analysis affirmed that the stretching vibrations of intermolecular and intramolecular interactions were significant in VI as against OD. The VI reduced the drying time by 35% compared to OD, with the highest overall acceptability score and lower microbial load during storage. PRACTICAL APPLICATION: Pineapple is a perishable fruit, which necessitates processing for extended shelf life. This study highlights the potential of the vacuum impregnation process as a promising alternative to conventional preservation methods such as osmotic dehydration for pineapples.

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.

Effect of the Pulsed Electric Field Treatment on Physical, Chemical and Structural Changes of Vacuum Impregnated Apple Tissue in Aloe Vera Juices

Vacuum impregnation (VI) stands as a diffusion-driven food processing method that has found recent application within the food industry, particularly for the cold formulation of fortified food products. Pulsed electric field (PEF) treatment can affect the food structure, influencing therefore the mass transfer phenomena during the further processing. Thus, the study aimed at investigating the effect of PEF treatment on selected physicochemical properties of vacuum-impregnated apples. Apple slices were vacuum impregnated with aloe vera juice solution with or PEF treatment at different intensities (125, 212.5 or 300 V/cm). The PEF was applied as a pretreatment-applied before the VI process as well as posttreatment-applied after the VI process. The VI process with aloe vera juice resulted in a sample weight increase of over 24% as well as structural changes, partial cell viability loss and color alteration. In addition, the decrease of bioactive compounds was observed, while antioxidant activity remained at a similar level as in raw material. PEF treatment adversely affected vacuum impregnation efficiency, causing microstructural changes and cell viability loss. Additionally, chemical composition modifications were evident through thermogravimetric analysis (TGA) and Fourier Infrared Spectroscopy (FTIR) analyses. Tissue hardness decreased significantly due to structural damage and caused high leakage from plant tissue, which resulted in hindering saturation with aloe vera juice during the VI process. Additionally, reduced bioactive substance content after PEF treatment was observed and the VI process did not restore apple samples of the bioactive compounds from aloe vera juice.

Nanofood Process Technology: Insights on How Sustainability Informs Process Design

Nanostructured products are an actively growing area for food research, but there is little information on the sustainability of processes used to make these products. In this Review, we advocate for selection of sustainable process technologies during initial stages of laboratory-scale developments of nanofoods. We show that selection is assisted by predictive sustainability assessment(s) based on conventional technologies, including exploratory ex ante and "anticipatory" life-cycle assessment. We demonstrate that sustainability assessments for conventional food process technologies can be leveraged to design nanofood process concepts and technologies. We critically review emerging nanostructured food products including encapsulated bioactive molecules and processes used to structure these foods at laboratory, pilot, and industrial scales. We apply a rational method via learning lessons from sustainability of unit operations in conventional food processing and critically apportioned lessons between emerging and conventional approaches. We conclude that this method provides a quantitative means to incorporate sustainability during process design for nanostructured foods. Findings will be of interest and benefit to a range of food researchers, engineers, and manufacturers of process equipment.

Vacuum Impregnation Process Optimization for Tilapia with Biopreservatives at Ice Temperature

The vacuum impregnation (VI) process was used to pretreat tilapia fillets with biopreservatives at −2 °C. Response surface methodology (RSM) was utilised to optimize processing conditions, including vacuum pressure (p_v), vacuum maintenance time (t₁), and atmospheric pressure recovery time (t₂), which were determined to be 67.73 kPa, 23.66 min, and 8.87 min, respectively. The anticipated values for the aerobic plate count (APC), total volatile basic nitrogen (TVB-N), and comprehensive score (CS) were 5.17 lg CFU/g, 14.04 mg/100 g, and 0.98, respectively. Verification experiments were conducted, and the experimental results for APC and TVB-N deviated from the predicted values by 0.19% and 0.64%, respectively. After 30 days of storage following VI and atmosphere impregnation (AI) pretreatment, the water-holding capacity (WHC), APC, TVB-N, hardness, and whiteness were determined. On the 30th day, the results for VI pretreatment were 63.38%, 6.27 lg CFU/g, 17.41 mg/100 g, 3.11 N, and 47.73, respectively. Compared with AI pretreatment, WHC, hardness, and whiteness increased by 14.8%, 18.6%, and 6.3%, respectively, whereas APC and TVB-N decreased by 11.3% and 29.6%, respectively. This study demonstrates that when biopreservatives are applied during the pretreatment process, VI technology can be utilised to facilitate their penetration into the interior of tilapia, hence significantly enhancing the effect of ice-temperature preservation.

Effect of Different Processing Methods on Quality, Structure, Oxidative Properties and Water Distribution Properties of Fish Meat-Based Snacks

Snack foods are consumed around to globe due to their high nutrition, taste and versatility; however, the effects of various processing methods on quality, structure and oxidative properties are scare in the literature. This study aims to evaluate the effect of various processing methods (frying, baking and microwave cooking) on quality, structure, pasting, water distribution and protein oxidative properties of fish meat-based snacks. The results showed that the frying method induced a significantly (p < 0.05) higher expansion than baking and microwave methods. Texture in terms of hardness was attributed to the rapid loss of water from muscle fiber, which resulted in compact structure and the increased hardness in microwave cooking, whereas in frying, due to excessive expansion, the hardness decreased. The pasting properties were significantly higher in baking, indicating the sufficient swelling of starch granules, while low in microwave suggest the rapid heating, which degraded the starch molecules and disruption of hydrogen bonds as well as glycosidic linkage and weakening of granules integrity. The water movement assessed by Low Field Nuclear Magnetic Resonance (LF-NMR) showed that frying had less tight and immobilized water, whereas microwave and baking had high amounts of tight and immobilized water, attributing to the proper starch-protein interaction within matrix, which was also evidenced by scanning electron microscopy (SEM) analysis. The protein oxidation was significantly (p < 0.05) higher in frying compared to baking and microwave cooking. The findings suggest the endorsement of baking and microwave cooking for a quality, safe and healthy snacks.

Fortification of raw rice and rice flour using Cissus quadrangularis L. (veldt grape) stem powder to overcome osteoporosis and its associated skeletal complication through staple diet

This study aimed to prepare the fortified rice/flour with Cissus quadrangularis (CQ) stem powder to eliminate nutritional deficiency and improve bone health. Mineral analysis by atomic absorption spectroscopy revealed that the CQ stem has adequate quantities of calcium, magnesium, and a moderate amount of phosphorous to meet the Recommended Dietary Allowance (RDA). Thus, the rice and flour were fortified with freeze-dried CQ stem powder to improve its nutraceutical contents. The fortification was done using standard vacuum impregnation and blending process. Furthermore, the recuperative activity of prepared fortified rice (CQFR) and flour (CQFF) was tested in chemically induced osteoporosis and osteoarthritis animal models. The efficiency of CQ fortified diet against these complications was confirmed by hematology, radiology, and histopathological analysis. The rat groups fed with CQFF/CQFR diet showed significant improvement from calcium deficiency and its allied physiological damage. Thus, this study confirms that the CQ fortified rice would provide recovery from skeletal complications associated with calcium deficiency through fixing both homeostasis and bio-accessibility of the calcium. PRACTICAL APPLICATIONS: Micronutrient and mineral deficiency is relatively higher in the regions where rice/rice products are consumed as a staple diet. Dietary intake of calcium and some essential minerals have major influences on bone and joint health. Cissus quadrangularis (CQ) is a familiar herb, conventionally used in India to fix broken bones and strengthen the skeletal system. The Atomic absorption spectroscopy data from this study showed that the CQ stem holds a high amount of calcium and other essential minerals to promote skeletal health. Preparation of fortified rice and flour with CQ stem would be a beneficial source of the essential minerals/ bioactive principles to promote and sustain skeletal health in the underprivileged population. These study data substantiated the practical application of producing the CQ fortified nutraceutical staple diet, especially to the people who are afflicted with morbid skeletal complications.

Physicochemical and Quality Properties of Dried Courgette Slices: Impact of Vacuum Impregnation and Drying Methods

The aim of this study was to determine the effects that the type of impregnating solution and drying method (freeze drying (FD) and vacuum drying (VD) at 45 °C and convective drying (CD) at 50, 60, and 70 °C) had on the physicochemical and quality properties of courgettes. Courgette slices were vacuum-impregnated (6 kPa) in freshly squeezed onion, kale, and onion and kale (50:50) juices with 3% NaCl solution (N). The application of vacuum impregnation (VI) with impregnating solutions from freshly squeezed onions and kale had a beneficial effect on the bioactive values of courgette. The highest contents of quercetin (41.84 μg/g d.m.) and carotenoids (276.04 μg/g d.m.) were found in courgette impregnated with onion juice after freeze drying. The highest values of lutein and zeaxanthin (216.42 μg/g d.m.) were recorded for courgette impregnated with kale juice and convective dried. By analysing the kinetics of convective drying, the best matching of the logistic model was found. Increasing the drying process temperature from 50 to 70 °C reduced the drying time from 15% to 36%, depending on the type of impregnating solution used. Water activity < 0.6 was recorded for courgette dried by freezing, vacuum, and convection at 60 and 70 °C. Conclusions: The vacuum impregnation process and the impregnation solutions from freshly squeezed vegetables can be used to develop new snacks with high levels of bioactive compounds. The FD method is the most appropriate considering both the bioactive compounds content and the obtained colour and water activity.

Combining ethanol pre-treatment and ultrasound-assisted drying to enhance apple chips by fortification with black carrot anthocyanin

BACKGROUND

An interesting approach to improve dried foods nutritional properties, functionality, and sensorial attributes, is by taking advantage of pre-treatments for incorporating components into the food matrix. Based on this, this work studied the incorporation of black carrot anthocyanins in apple tissue by using ethanol (concentrations 0-300 mL L^-1 ) as a pre-treatment to ultrasound-assisted convective drying. Samples were pre-treated in acidified ethanol solutions, with and without anthocyanins, and then dried (50 °C, 1 m s^-1 ) by convective and ultrasound-assisted convective (21.77 kHz, 20.5 kW m^-3 ) drying. Both the drying process improvement and the obtained product properties were studied.

RESULTS

The anthocyanins did not influence the drying kinetics. In contrast, time reduction was > 50% by using both ethanol pre-treatments and ultrasound. Ethanol pre-treatments decreased the external resistance to mass transfer, while ultrasound decreased both internal and external resistances. The impregnation increased the anthocyanins (above 947%), which were retained after drying. Colour modifications after pre-treatments and after drying (L*, b*, h° decrease, and a* increase), and antioxidant capacity retention were observed in samples with anthocyanin addition.

CONCLUSION

The results point that ethanol pre-treatments and ultrasound application can accelerate drying, and through the natural colouring incorporation during pre-treatments, the nutritional properties of dried samples were better retained. © 2020 Society of Chemical Industry.

Effects of vacuum soaking on the hydration, steaming, and physiochemical properties of japonica rice

Soaking is an essential step in the processing of various rice products. In this study, the influences of vacuum soaking on hydration, steaming, and physiochemical properties of rice were investigated. Results showed that vacuum soaking accelerated water absorption as well as affected the mobility and density of water protons inside rice during soaking. Vacuum soaking could considerably shorten the optimal steaming time from 58 to 32 min and reduce the adhesiveness of steamed rice. Microstructure analysis of rice revealed that porous structure was formed on rice surface and the arrangement of starch granules became loosened after vacuum soaking. Moreover, vacuum soaking slightly reduced the relative crystallinity of rice starches without altering the crystalline type. The gelatinization temperature as well as the peak and trough viscosity was also decreased after vacuum soaking. Our study suggested that vacuum soaking was conducive to improve the soaking and steaming properties of rice.

Impregnation and drying to develop a melon snack enriched in calcium

Melon fortification with calcium by impregnation techniques using a vacuum and/or ultrasound and drying were combined to obtain a snack product. For the impregnation step, samples were immersed in a 2 g 100 mL^-1 calcium chloride solution at 25 °C. The samples were dried at 60 °C and an air velocity of 2 m s^-1. The influence of the impregnation method on drying kinetics, mass variation, calcium content, water activity, color, and texture was evaluated. All dried samples had reduced water activity. The vacuum impregnated (VI) melons presented higher mass gain and drying time. It resulted in the highest calcium incorporation, increasing up to 13 times the calcium concentration of the samples. The samples dried after submitted to VI showed the greatest differences in color and hardness. However, VI was the most effective technique for calcium incorporation, being the only one capable of producing fortified dried melon.

Influence of In Vitro Digestion on Antioxidant Activity of Enriched Apple Snacks with Grape Juice

Fruits are sources of bioactive compounds (BACs), such as polyphenols. This research aimed to study the in vitro bioaccessibility of polyphenols from enriched apple snacks with grape juice and determine their antioxidant capacity. Impregnation (I) treatments were carried out at atmospheric pressure and in a vacuum (IV) at 30, 40, and 50 °C and their combinations with ohmic heating (OH), I/OH, and IV/OH. Later, samples were dehydrated by forced convection at 40, 50, and 60 °C. Enriched samples were subjected to in vitro digestion. The total polyphenols, monomeric polyphenols, and antioxidant activities were determined from recovered extracts. Results showed that total polyphenols present in higher concentrations in the gastric phase, 271.85 ± 7.64 mg GAE/100 g d.m. Monomeric polyphenols' behavior during in vitro digestion for the VI/OH 50 °C and dried treatment (60 °C) was descending, mainly in quercetin, which decreased by 49.38% concerning the initial concentration, before digestion. The cyanin, catechin, epicatechin, and epigallocatechin decreased by 26.66%, 20.71%, 23.38%, and 21.73%, respectively. Therefore, based on obtained results, the IV/OH 50 °C treatment (dried 60 °C) is the best combination to incorporate polyphenols from grape juice.

Time and energy reduction on grape dehydration by applying dipping solution on freeze drying process

To preserve freshness and nutritional quality of fruits and vegetables is required large energy expenditure due to most storage techniques require low temperatures, making the product difficult to transport and store.

PURPOSE

To reduce energy expenditure, dehydration processes are being improving by pretreatments and changing frozen stage.

METHOD

Alkaline emulsion pretreatment was introduced to freeze-drying method to reduce the drying time of grapes and obtain significant energy savings.

RESULTS

Dehydration process for untreated fresh grape samples was 22 hours, using industrial freeze-drying equipment. It was obtained a high quality product with range 3 % to 7% of final humidity, without losing natural characteristics and organoleptic properties of the grapes.

CONCLUSIONS

it was found by modifying standard equipment frozen method, using dry ice (CO2) and applied coconut oil alkaline emulsion pretreatment, a 54% energy saving. Even more the dehydration process decreased the microbial load in the fruit. A product with low number of microorganisms may be consumed by patients with low defenses as cereals, nutritional bars, salads, yogurts, etc. Finally, if all enterprises involved in this field take into account these findings and improve constantly their process they will stop emitting several kg of CO2 into the atmosphere.

Spectrum crispness sensory scale correlation with instrumental acoustic high-sampling rate and mechanical analyses

Mechanical and acoustical instrumental tests can help to predict and compare the sensory crispness of food products. This study proposed a method to correlate crispness sensory analyses to instrumental parameters using the standard products of the Spectrum Crispness Sensory Scale. An acoustic system was developed with a high-sampling rate for characterizing food crispness. Force-displacement and acoustic signals were measured during penetration and compression tests of the products in the Spectrum Scale. A band-pass filter suppressed the texture analyzer's engine and gearbox noise. High correlations were obtained between acoustical and sensory parameters in both tests; however, the penetration test better differentiated the products. The high-sampling rate acoustical measurement system was capable of discriminate crispy products, although the trained sensory panel was still more sensitive to small differences.

Studies on the Effect of Mass Transfer in Vacuum Impregnation on the Bioactive Potential of Apples

The purpose of the study was to evaluate the efficiency of mass transfer during vacuum impregnation (VI) of apple tissue by different process conditions. VI was carried out in two stages: Vacuum (4, 6, or 8 kPa maintained at time 10, 20, 30, 40, 60, and 80 s) and atmospheric (4 min under atmospheric pressure). As infiltration liquids, fresh squeezed apple-pear juice (J), 3% citric acid solution (C), and distilled water (DW) were used. Mass transfer was analyzed based on three factors: Mass variation (MV), dry mass variation (DMV), and solid gain (SG). The outflow of native components and inflow of infiltration liquid has been described by mathematical models. The polyphenol content and antioxidant capacity (ABTS⁺, FRAP) were evaluated as the bioactive potential factors confirming native component outflow and incorporation of liquid molecules into an apple tissue. It was found that during VI of an apple tissue, intensive mass transfer occurred: Native components of fruit tissue outflowed and external ingredients of impregnation liquid inflowed into the material with the intensity proportional to the vacuum level and process time. The most beneficial conditions of apple cube VI were noticed at a vacuum level of 4 kPa for a minimum of 40 s, which is when the highest polyphenol content and antioxidant capacity occurred.

Manufacturing personalized food for people uniqueness. An overview from traditional to emerging technologies

Personalized nutrition means that we are unique in the way to absorb and to metabolize nutrients as a consequence of our genetic profile and the microbiome that we host in the gut. With the terminology of Personalized Food Manufacturing we want not only to stress the idea of the capability to manufacture food meeting our unique nutritional needs but - based on the idea that eating is a global experience - also to broad this to meet additional personal requirements and expectations, i.e. taste, texture, color, aspect, etc. To address this aim, traditional and advances technologies will have to be employed in new ways and new technological solutions will have to be implemented. All these considerations motivated our paper by which we want to explore and to discuss the technological options having the potential to produce personalized food. After pointing out the main diet styles, firstly we have analyzed the modern approaches of agricultural and animal nutrition in use to manufacture food for narrow group of consumers. Secondly, we have explored emerging technologies at disposal employable to manufacture customized food that meet our uniqueness. Finally the most important market products belonging in the sector of personalized food production have been considered.

Innovative technologies for producing and preserving intermediate moisture foods: A review

Intermediate moisture foods (IMF) or semi-dried foods (SDF) have gained more attention worldwide having features very similar to fresh food products, but with a longer shelf life. This review presents the recent developments in novel technologies and methods for the production and preservation of IMF. These include new drying methods, using agents to reduce water-activity, innovative osmotic dehydration technologies, electro-osmotic dewatering, thermal pasteurization, plasma treatments (PT), high pressure processing (HPP), modified atmosphere packaging (MAP), edible coating, active packaging (and energy efficiency, improve quality and extend the shelf life of the final food AP) and hurdle technologies (HT). Innovative methods applied to producing and preserving IMF can enhance both drying products. Yet more systematic research is still needed to bridge knowledge gaps, in particular on inactivation kinetics and mechanisms related to thermal and non-thermal pasteurization technologies for control of pathogens and spoilage micro-organisms in IMF.

The Influence of Vacuum Impregnation on Nutritional Properties of Fluidized Bed Dried Kale (Brassica oleracea L. Var. Acephala) Leaves

The aim of the work was to assess the possibility of obtaining high bioactivity dried kale using a vacuum impregnation as the preliminary processing before the drying. Kale leaves underwent vacuum impregnation in freshly squeezed onion juice and in sodium chloride solution utilising the following impregnation process parameters: At the vacuum stage, 6 kPa reduced pressure for 1 min, dosing the impregnating solution and keeping the sample under vacuum for 2 min, and then 6 min in impregnating solution at atmospheric pressure. Fluidized bed drying of kale was conducted using inert polypropylene balls, utilising a drying air temperature in a range from 70 to 130 °C. The drying kinetics were described, and the dehydrated product’s quality was assessed, on the basis of these selected characteristics: The content of chlorophylls, polyphenols and carotenoids, and antioxidant activity measured with ABTS⁺, dry matter, water activity and colour. It was determined that protective influence of vacuum impregnation before fluidized bed drying was seen only in the case of using temperatures of 90 and 110 °C. The highest content of bioactive components in dried kale was obtained in the case of using onion juice impregnation and drying at 110 °C.