Alicja Barańska

Spent osmotic solutions (sucrose, buckwheat honey, acacia honey, apple juice concentrate, chokeberry juice concentrate, cherry juice concentrate, and mannitol) were tested for their valorization to produce powders by spray drying. Simultaneously, the application of inulin as an alternative carrier was verified. The drying yield varied from 6 to 92%. For acacia honey, apple juice concentrate, chokeberry juice concentrate, and cherry juice concentrate, high stickiness was observed, which resulted in low yield and the production of significantly bigger particles of regular size distribution, higher hygroscopicity and bulk density, and better flowability. Sucrose, acacia honey, and mannitol were dried with lower stickiness, and the physical properties of the powders were acceptable. However, the yield of mannitol drying was low due to very small particles, low bulk density, and low cyclone efficiency. Therefore, sucrose and buckwheat honey solutions can be successfully spray dried using inulin as a carrier to produce powders suitable for further food applications. However, for the other tested materials, alternative carriers should be considered to reduce stickiness during drying.

A three-stage research using distilled water and maltodextrin as model feed solutions was conducted to study the influence of inlet air humidity on spray drying performance. In the first and second stage, spray drying of distilled water and 30% (solids, w/w) MD solutions were tested at variable feed rate (0.16–0.83 mL/s), inlet air humidity (0.1–0.3, 1.1–1.3, 9–10 g/m³) and inlet air temperature (80–120 °C). In the third stage, the optimization of MD solutions spray drying process variables (80–120 °C inlet air temperature, 0.1–0.3, 1.1–1.3, 9–10 g/m³ inlet air humidity, 10–30% feed solution concentration) were verified for maximum powder recovery and powders of low moisture content and activity. It was noted that inlet air humidity influenced the spray drying performance. Reduced humidity improved the process conditions, but the most satisfying powder properties were noted at 120 °C, thus decreasing inlet air temperature was not necessary to ameliorate the process performance. Optimization in the third stage of the study enabled us to estimate the most satisfying properties of maltodextrin powders. The highest powder recovery and the lowest moisture content and water activity were optimal for spray drying at inlet air temperature of 120 °C, inlet air humidity of 0.1 g/m³, and feed solution concentration of 29.571%.

Young barley leaves have been proven to distinguish themselves as highly potent in antioxidant activity, resulting from a high content of bioactive compounds. Due to their short storage time, it is crucial to prolong their shelf life. One of the methods that can be used is spray-drying, as it enables the production of powders that are highly valued in the food industry. This paper aimed to analyze the possibility of producing young barley leaf juice with improved properties. Juices were spray-dried with and without carriers at 100/60 °C inlet/outlet temperature using air of 1.5 g/m³ humidity as the drying medium. Maltodextrin (MD), Nutriose^® (N), and Arabic gum (AG) were used in a ratio 1:3 carrier/juice solids. The results proved that dehumidified air application enabled the production of young barley leaf juice powder, that was free of the carriers, of high retention coefficient (RC) of chlorophyll A and B (80.84 ± 6.56% and 87.05 ± 5.21%, respectively). No statistical difference was noted between variants with maltodextrin (chlorophyll A: 91.22 ± 5.07%, chlorophyll B: 71.72 ± 5.44%), Nutriose^® (chlorophyll A: 72.24 ± 5.32%, chlorophyll B: 67.04 ± 12.41%), and carrier-free powder; thus, the elimination of a carrier can be considered to effectively produce a “clean” label, functional product. The highest degradation among the tested bioactive compounds was noted for vitamin C.

The aim of this work was to determine the impact of pulsed electric field treatment of beetroots on select physicochemical properties of the obtained juice, spray-dried juice, and freeze-dried pomace. Pulsed electric field pretreatment of beetroots was conducted with a different number of pulses (3 or 44 pulses) at a constant electric field strength of E = 1.07 kV/cm, which resulted in the total energy levels of 0.5 and 4 kJ/kg. The juice was dehumidified and air spray-dried with NUTRIOSE® as a drying carrier at 90/60 °C, while pomace was freeze-dried at 0.63 Pa and a shelf temperature of 20 °C. Pulsed electric field (PEF) treatment caused an increase in pigment content in beetroots and the juice. In the case of powders, the following effects were noted: a decrease in drying efficiency, changed powder color, decreased powder particle diameter. Dried juice and pomace treated with a higher pulsed electric field (PEF) treatment were characterized by the highest hygroscopicity.

The aim of this study was to evaluate the quality of cloudy beetroot juice powders with or without a carrier obtained by spray drying using an innovative method of dehumidified air that enabled drying in low temperatures and, consequently, with a reduced carrier content. Phenolic content, betacyanin content, antioxidant activity and the content and types of aromatic compounds of the produced powders were examined. Powders obtained at a lower temperature (90 °C) without carriers were characterized by the highest share of aromatic volatile compounds, the highest content of betalains and polyphenols and the highest antioxidant activity. The addition of carriers (including the variant with added pomace as a natural type of carrier) did not indicate the protection of the active substances present in the juice. The powders obtained with carrier addition compared with those without the carrier addition were characterized by lower antioxidant activity, lower content of betalains and polyphenols and a lower amount of aromatic volatile compounds. No significant differences were found in the content of bioactive and aromatic compounds between powders obtained using different carriers (skim milk powder, Nutriose, maltodextrin and kleptose).

BACKGROUND: Sour cherry juice concentrate powder can serve as a modern, easy‐to‐handle, phenolics‐rich merchandise; however, its transformation into powdered form requires the addition of carriers. In line with the latest trends in food technology, this study valorizes the use of dairy by‐products (whey protein concentrate, whey, buttermilk, and mixes with maltodextrin) as carriers. A new multiple approach for higher drying yield, phenolics retention (phenolic acids, flavonols and anthocyanins) and antioxidant capacity of powders were tested as an effect of simultaneous decrease of drying temperature due to the drying air dehumidification and lower carrier content.RESULTS: Dairy‐based carriers were effective for spray drying of sour cherry‐juice concentrate. The drying yield was increased and retention of phenolics was higher when compared with maltodextrin. The application of dehumidified air, which enabled the drying temperature to be reduced, affected drying yield positively, and also affected particle morphology and retention of phenolics (the phenolic content was approximately 30% higher than with spray drying).CONCLUSIONS: The study proved that it is possible to apply dairy‐based by‐products to produce sour cherry juice concentrate powders profitably, lowering the spray‐drying temperature and changing the carrier content. Dehumidified air spray drying can be recommended for the production of fruit juice concentrate powders with improved physicochemical properties. © 2023 Society of Chemical Industry.

The study examined the effects of pulsed electric field treatment on the kinetics and properties of convective-dried mushrooms using different drying agents. Increasing the drying air temperature reduced drying time, while the use of dehumidified air resulted in faster water removal. PEF treatment, depending on the parameters, shortened the drying time maximum by 12% or extended the drying time. The physical (dry matter content, rehydration properties, hygroscopic properties, and color) and chemical (polyphenols content and anti-oxidant activity) properties were analyzed. The dry matter contents of the mushrooms were influenced by the drying temperature, while PEF pre-treatment did not influence the rehydration and hygroscopic properties in both cases of drying using air humidity. However, the color parameters were affected by the drying method and energy input, with higher energy input leading to decreased lightness, increased redness, and color saturation. The chemical analyses revealed that the anti-oxidant compounds in the dried mushrooms were influenced by various factors, with PEF treatment and drying non-dehumidified air polyphenol content increasing, whereas dehumidified air caused more phenolic degradation if it was combined with PEF treatment. Anti-oxidant activity varied depending on the drying agent, with non-dehumidified air generally exhibiting better properties. The highest total polyphenol content and best anti-oxidant properties were obtained for the PEF pre-treated with 3 kJ/kg of energy and dried with non-dehumidified air at a temperature of 70 °C.

The application of low-temperature, dehumidified air-assisted spray drying was evaluated as a method to produce carrier-free powders of selected sugar-rich and acid-rich food materials: blackcurrant juice concentrate, mango puree, purple carrot juice concentrate, sauerkraut juice, kiwiberry pulp,...

Spray drying of sour cherry juice concentrate was performed by conventional high temperature method (180 °C/80 °C, inlet/outlet air), as well as by innovative approach with dehumidified air and low drying temperature (80 °C/45 °C, inlet/outlet air). Moreover, the possibility to apply pea protein as an alternative carrier to partially replaced maltodextrin was tested. Due to lower drying temperature and reduced stickiness the carrier content was reduced from 50% down to 30% solids to enhance powders physiochemical properties (lower stickiness, hygroscopicity, better color, better bioaccessibility), although some parameters of variants produced with the addition of pea protein had poorer quality in comparison to powders with only maltodextrin (moisture content, water activity, particles morphology and size, glass transition temperature). Increased bioaccessibility of phenolics and antioxidant potential of pea protein-enriched samples indicated the potentially possible application in functional food.

Fourier transform infrared spectroscopy (FTIR) in connection with chemometric analysis were used as a fast and direct approach to classify spray dried honey powder compositions in terms of honey content, the type of diluent (water or skim milk), and carrier (maltodextrin or skim milk powder) used for the preparation of feed solutions before spray drying. Eleven variants of honey powders containing different amounts of honey, the type of carrier, and the diluent were investigated and compared to pure honey and carrier materials. Chemometric discrimination of samples was achieved by principal component analysis (PCA), hierarchical clustering analysis (HCA), linear discriminant analysis (LDA), and partial least squares-discriminant analysis (PLS-DA) modelling procedures performed on the FTIR preprocessed spectral data for the fingerprint region (1800–750 cm⁻¹) and the extended region (3600–750 cm⁻¹). As a result, it was noticed that the type of carrier is a significant factor during the classification of different samples of powdered multifloral honey. PCA divided the samples based on the type of carrier, and additionally among maltodextrin-honey powders it was possible to distinguish the type of diluent. The result obtained by PCA-LDA and PLS-DA scores yielded a clear separation between four classes of samples and showed a very good discrimination between the different honey powder with a 100.0% correct overall classification rate of the samples.