Ultrasound-assisted Vacuum Research Articles

Ultrasound-assisted vacuum drying of limequat peels and characterization of thermal, morphological and functional properties

This work aimed to determine drying behavior and energy consumption of limequat peels dried using ultrasound-assisted vacuum drying (UAVD), vacuum-assisted drying (VAD), oven drying (OD) and vacuum drying (VD), and investigate thermogravimetric decomposition, morphological, elemental and spectral analyses of dried peels with energy efficiency analysis including specific moisture extraction rate (SMER), moisture extraction rate (MER) and specific energy consumption (SEC). The UAVD considerably shortened drying time by 49 %, 34 % and 15 % as compared to the OD, VAD and VD. The highest drying rate was achieved at the UAVD. The effective moisture diffusivity(Deff) values in descending order were UAVD>VD>VAD>OD. Proximate analysis showed that limequat peels dried using the UAVD had the highest fixed carbon (25.35 %) and ash (3.03 %) contents, but the lowest volatile matter (61.68 %). Dried limequat peels exhibited similar thermal decomposition behavior. The UAVD caused porous and rough surface formation, and microchanneling effect. Carbon (>62.56 %) and oxygen (>15.98 %) were the major elements in dried limequat peels. The lowest O/C (0.25) and H/C (0.85) ratios were obtained for the limequat peels dried using the UAVD. Fourier-transform infrared spectroscopy (FTIR) spectra showed primarily O–H, C–H, CO, CC and C–O–C stretching vibrations. The highest SMER (0.0053 kg/kWh) and MER (0.0012 kg/h) values, and the lowest SEC (188.27 kWh/kg) value were determined for the UAVD. In conclusion, the UAVD was found to be the most appropriate drying method for the drying of limequat peels.

Effect of Ultrasound-Assisted Vacuum Far-Infrared on the Drying Characteristics and Qualities Attributes of Cistanche Slices

This study applied direct-contact ultrasound-assisted Vacuum Far-Infrared (VFIR) to dry Cistanche slices, investigating the influence of radiation temperature (45 °C, 55 °C, 65 °C), ultrasonic frequency (20 kHz, 40 kHz, 60 kHz) and ultrasonic power (72 W, 96 W, 120 W) on the physicochemical properties, drying characteristics, and microstructure of Cistanche slices. The results showed that the application of ultrasound had a significant enhancement effect on the drying process, with drying time decreasing as radiation temperature, ultrasonic power, and ultrasonic frequency increased. The drying rate curves under three experimental factors exhibited a brief acceleration stage followed by a deceleration stage. Under different drying conditions, the contents of Iridoid and phenylethanoid glycosides in dried products were higher than those under natural drying (ND). Specifically, the content of catalpol at 55 °C, 96 W, 40 kHz (0.56 mg/g) and the content of Leonuride at 55 °C, 96 W, 60 kHz (0.67 mg/g) increased by 1.81 and 1.9 times, compared to ND. The rest of the nutrient content and antioxidant activity increased with the increase in ultrasonic frequency. Compared to ND, ultrasonic-assisted VFIR drying improved the color and rehydration capacity of dried products. Observation of the microstructure revealed that the application of ultrasound made the interior of Cistanche slices loose and porous. In summary, ultrasonic-assisted VFIR drying not only enhances the drying rate but also improves the quality of dried products.

Effects of ultrasonic power on drying kinetics and product quality of licorice extract during ultrasound-assisted vacuum drying.

Licorice extract is an important raw material for food additives and medicine. The quality of licorice extract is dictated by the drying process. The commonly used drying methods of licorice extract are not efficient in obtaining high-quality products so alternative techniques need to be developed and researched. In this study, ultrasound-assisted vacuum drying (UAVD) was first utilized to improve drying efficiency and produce a higher-quality product. The changes in water mobility of licorice extract during drying were characterized using low-field nuclear magnetic resonance. In addition, the effects of ultrasonic power on the drying dynamics, the contents of liquiritin and glycyrrhizic acid, the antioxidant capacity and the microstructure formation of licorice extract during the whole drying process were investigated. The drying times for licorice extract to reach equilibrium moisture content were reduced by 9.09-69.70% with UAVD at 40-200 W compared with that without ultrasonic treatment (0 W). Moreover, the proportions of bound water and semi-bound water in fresh concentrate were 3.75% and 96.25%. It was also found that high ultrasonic power promoted the flow of water and the formation of porous structure in licorice extract, which led to the improvement of drying efficiency. The contents of liquiritin (2.444%) and glycyrrhizic acid (6.514%) were retained to a large degree in the dried product at an ultrasonic power of 80 W. The DPPH inhibition rate of UAVD samples with different ultrasonic powers ranged from 84.07 ± 0.46% to 90.65 ± 0.22%. UAVD has the advantages of high efficiency and low energy consumption, which may be an alternative technology for vacuum drying widely used in industry. © 2024 Society of Chemical Industry.

Modeling of sage (Salvia fruticosa Miller) phenolics diffusion in meat cubes during ultrasound assisted vacuum impregnation

This study aimed to investigate the modelling of the transport of sage phenolics into meat cubes under various vacuum impregnation (VI) conditions (Control, VI-100, VI-250, and VI-500 mbar; ultrasound-assisted (UA) VI-100, VI-250, and VI-500 mbar). Azuara model from five different models has been proposed as a model that can be used successfully in describing kinetic parameters. After 180 min of treatment, the phenolic contents of the samples were determined between 462.7 and 639.8 mg/kg. Although the highest phenolic content (639.8 mg/kg) was obtained in the samples applied UAVI-100, the highest equilibrium phenolic content was calculated in the samples applied VI-100 in the calculations performed with the Azuara model. In addition, the diffusion coefficients calculated for the samples varied between 8.5 × 10−6 and 11.4 × 10−6 m2/s.

Effect of Different Drying Techniques on Total Bioactive Compounds and Individual Phenolic Composition in Goji Berries

In recent years, interest in the consumption of dried goji berries has increased due to its high bioactive properties. Alternative drying methods that provide faster drying and better preservation of bioactive properties should be developed. This study aims to investigate the effect of different drying methods on the drying time and quality characteristics of the goji berry; namely, hot-air drying (HAD), ultrasound-assisted vacuum drying (USVD), vacuum drying (VD), freeze-drying (FD), and ultrasound-pretreated freeze-drying (USFD). The drying kinetic, total phenolic content, antioxidant capacity, phenolic profile, carotenoid profile, and color change of the goji berry fruit were determined. The drying times for VD, USVD, and HAD varied between 275–1330 min. USVD treatment showed faster drying behavior than the other two drying methods. The total phenolic content (TPC) value of dry samples varied between 1002.53–1238.59 mg GAE/g DM. USVD treatments exhibited a higher total phenolic content (TPC) value than all other drying methods. DPPH and CUPRAC values varied between 15.70–29.90 mg TE/g DM and 40.98–226.09 mg TE/g DM, respectively. The total color change (ΔE) value ranged between 4.59 and 23.93 and HAD dried samples showed the highest ΔE of all samples. The results of the phenolic profile were consistent with TPC analysis. HAD caused higher phenolic compound degradation than VD, USVD, and FD. The results of this study showed that different drying techniques significantly affected the drying rate and retention of bioactive components of the goji berry fruit, and the USVD and VD methods could be used as an alternative to the HAD method. This study concluded that USVD and FD could be considered as suitable drying methods and could be used as alternatives to HAD in the drying of goji berries.

Influence of Ultrasound-Assisted Vacuum Drying on Physicochemical Characteristics, Antioxidant Activity, and α-Glucosidase Inhibition Activity of Flos Sophorae Immaturus.

Flos Sophorae Immaturus (FSI) contains a large number of bioactive substances with antioxidant and hypoglycaemic activity. However, a feasible drying process plays an important role in the retention of its biological activity. The present work investigated the effects of ultrasound-assisted vacuum drying (UAVD) on FSI samples in terms of drying time, colour, microstructure, and total flavonoid content (TFC). Meanwhile, the antioxidant activity and α-glucosidase inhibition activity were also evaluated. The results show that the drying time of UVAD samples was decreased by 40% compared to that of the single vacuum-dried (VD) samples (600 W for 10 min). The cellular porous structures of FSI tissue were formed by UAVD, which promoted the migration of water from the inside to the outside. Furthermore, samples treated by UAVD exhibited better antioxidant activities and α-glucosidase and α-amylase inhibition capacities, with DPPH (81.86%), ABTS (88.61%), FRAP (83.05%), α-glucosidase inhibition capacity (89%), α-amylase (85%), drying time (3 h), and total aberration (ΔE) (1.63) being the highest characteristic traits. In this condition, the highest levels of total flavonoid content (TFC), rutin, quercetin, kaempferol, isorhamnetin, and genistein were obtained with 266.94, 239.46, 35.56, 8.54, 10.37, and 5.64 mg/g DW, respectively. The results confirm that UAVD is a novel method that significantly reduced the VD time and promoted the release of the bioactive substances of FSI.

Effect of ultrasound assisted vacuum osmotic dehydration on the mass transfer kinetics and qualities of orange slices

This research aimed to explore the effects of combined ultrasound and vacuum assisted osmotic dehydration on the mass transfer kinetics and qualities of fresh-cut orange slices. The experiments were carried out under four different conditions, i.e., osmotic dehydration (OD), vacuum osmotic dehydration (VOD), ultrasound assisted osmotic dehydration (UOD) and ultrasound assisted vacuum osmotic dehydration (UVOD). Aqueous solutions of the four osmotic agents – sucrose, xylitol, sorbitol, and maltitol at a concentration of 50°Brix were used in each condition. The results showed that UVOD had the highest (p < 0.05) water loss (WL) and solid gain (SG). The high regression coefficient (R2 > 0.99) and low χ2 and RMSE values revealed the applicability of Peleg model for fitting mass transfer of orange slice during osmotic dehydration. Low-field nuclear magnetic resonance (LF-NMR) spectra revealed the water distribution in orange cells. Electronic nose data indicated that osmotic dehydration did not significantly (p > 0.05) change the flavor of orange slices. Fourier transform infrared (FTIR) spectra indicated osmotic dehydration could preserve internal chemical composition of orange slice. Scanning electron microscope (SEM) images illustrated the mechanisms of VOD, UOD and UVOD. The results of mass transfer kinetics and qualities showed that sugar alcohols were good alternative osmotic agents to sucrose. Although UVOD led to the largest loss of vitamin C due to its highest WL, UVOD exhibited better hardness and could combine the advantages of VOD and UOD in water activity and color, respectively.

Assessment of ultrasound-assisted vacuum impregnation as a method for modifying cranberries’ quality

Combined vacuum impregnation and ultrasound was proposed as an alternative method to improve the infusion of ascorbic acid in berry fruit. The effect of ultrasound application at different stages of impregnation – vacuum, relaxation, and both stages – on the qualitative characteristics of impregnated cranberries was investigated. The quality assessment was based on porosity, color, antioxidant capacity, anthocyanin, polyphenol and structure compound content. Ultrasound-assisted vacuum impregnation contributed to higher ascorbic acid content, smaller relative color difference, and greater antioxidant properties. It was found that the degree of impregnation varies considerably and depends on the stage of using ultrasound. Due to more favorable quality attributes, the conclusion was reached that ultrasound should be applied during the relaxation stage of vacuum impregnation.

Convective drying of mango enriched with phenolic compounds from grape residue flour under different impregnation methods

This work evaluated the effect of convective drying of mango impregnated with grape residue flour polyphenols under different vacuum impregnation methods with or without performing osmotic treatment and ultrasound on the global quality of dried mango in relation to chemical, microbiological and sensory aspects. Higher retention of carotenoids, phenolic compounds, and ascorbic acid was obtained with shorter drying times and lower oxygen exposure. Impregnated dried samples submitted to ultrasound-assisted vacuum impregnation showed a higher drying rate, greater retention of carotenoids (6.77 µg/g DM), and softer samples. Greater retention of phenolic compounds (1.84 mg GAE/g DM) was obtained for osmotic dehydration-assisted vacuum impregnation dried mango, while osmosonication-assisted impregnation was able to retain the highest ascorbic acid content (7.05 mg/100 g DM). Sensory evaluation showed that the impregnated samples showed good acceptance. The combination of osmotic dehydration and ultrasound could be a suitable way to produce dried mango impregnated with grape residue polyphenols.

The effect of different drying methods on total bioactive properties, individual phenolic compounds, rehydration ability, color, and microstructural characteristics of Asian pear

This study aimed to investigate the effects of FD (freeze drying), USVD (ultrasound-assisted vacuum drying), HAD (hot air drying). and IRD (infrared drying) methods on drying behavior, total phenolic antioxidant activity, individual phenolic distribution, rehydration capacity, Scanning Electron Microscopy image, and color quality of Asian pear. HAD showed the longest drying period with 420 min and followed by USVD with 345 and IRD with 240 min. The method difference had a significant effect on the total phenolic and antioxidant activity values of the samples (p < 0.05). The TPC, DPPH, and CUPRAC value were found as 111.59–316.40 mg/100 g GAE, 336.94–559.41 mg/100 g TE, and 161.00–859.73 mg/100 g TE, respectively. Samples dried with FD showed the highest TPC and AA values, followed by USVD, IRD, and HAD. The effect of drying techniques on the distribution of phenolic compounds was found to be significant (p < 0.05). HAD and the IRD process caused a decrease in the amount of all identified phenolic compounds. While USVD caused an increase in the amount of Chlorogenic acid, FD did not cause a significant change. Higher HMF results were found in samples dried via IRD followed by HAD. While the porous structure was preserved in the samples dried with FD and USVD, the porosity structure of the samples dried with HAD and IRD completely disappeared. FD and HAD showed the highest and lowest rehydration capacity, respectively. FD and USVD showed lower color change than IRD and HAD. The results of this study showed that USVD and FD can be used as an alternative method to HAD in drying Asian pear. Practical Application Pear fruit is one of the most consumed fruits worldwide. Pear fruit is very sensitive to microbial and enzymatic degradation due to its high sugar, bioactive component, and moisture content. To increase the shelf life of the pear fruit and to ensure consumption throughout the year, it must be subjected to a preservation technique. Drying is one of the main methods used to extend the long shelf life of fruits and vegetables. Undesirable changes may occur in the quality characteristics of fruits during drying. Therefore, determining the appropriate drying method is vital for the quality of the final product. In this study, the effects of different drying methods on many quality characteristics of pear fruit were investigated. This study has the potential to provide a new perspective on the drying of pear fruit.

Extraction of essential oils from Kumquat peel using ultrasound‐assisted vacuum hydrodistillation

In the current study, ultrasound-assisted vacuum extraction (UAVE) was applied to improve the efficiency of hydrodistillation extraction (HDE) and vacuum hydrodistillation extraction (VHE) and produce Kumquat peel essential oil (EO) with acceptable quality. To achieve these objectives, the effects of ultrasound power (210–300 W), ultrasound time (15–40 min), and pressure (600–900 mbar) were evaluated. Results showed that the EO yield initially increased and then decreased with increasing ultrasound power, ultrasound time, and pressure, and the highest EO yield was achieved at 270 W, 20 min, and 800 mbar. The EO obtained by UAVE under conditions allowed a higher EO yield than VHE and less extraction time than HDE, and provided EO with higher antioxidant activity due to differences in chemical composition. Overall, the application of UAVE could be an effective approach to improve the extraction efficiency and quality of the Kumquat peel EO. Novelty impact statement Ultrasound-assisted vacuum hydrodistillation was applied to extract essential oil (EO). A comparative study on the ultrasound-assisted vacuum hydrodistillation extraction. Ultrasound-assisted vacuum hydrodistillation improved the antioxidant activity of EO.

Effects of Ultrasound-Assisted Vacuum Impregnation Antifreeze Protein on the Water-Holding Capacity and Texture Properties of the Yesso Scallop Adductor Muscle during Freeze–Thaw Cycles

The effect of antifreeze protein (AFP) on the water-holding capacity (WHC) and texture properties of the Patinopecten yessoensis adductor muscles during freeze–thaw cycles (FTCs) were evaluated based on three impregnation methods: general impregnation (GI), vacuum impregnation (VI), and ultrasound-assisted VI (US-VI). The WHC, texture properties, and tissue microstructure were all evaluated. Results showed that the WHC and texture properties of adductor muscle were significantly improved in the VI and US-VI groups during FTCs (p < 0.05). The WHC of the adductor muscle in the US-VI group was maximally enhanced in terms of yield (6.63%), centrifugal loss, cooking loss, and T22. The US-VI group of the adductor muscle had the optimal chewiness and springiness compared to others, and the shear force and hardness were most effectively enhanced by VI. The growth and recrystallization of ice crystals in the frozen adductor muscle were significantly inhibited by VI and US-VI. The average cross-sectional area and roundness of ice crystals in the US-VI group were decreased by 61.89% and increased by 22.22% compared with those of the control, respectively. The partial least squares regression (PLSR) model further confirmed that the WHC and texture properties of the adductor muscle were correlated appreciably with the degree of modification of ice crystal morphology through the AFP.

Effect of different drying methods on the bioactive, microstructural, and in-vitro bioaccessibility of bioactive compounds of the pomegranate arils

This study aimed to investigate the effect of different drying methods on the drying kinetic, total bioactive content, in-vitro bioaccessibility of bioactive compounds, and color and microstructural properties of pomegranate arils. Drying methods significantly affected all selected parameters of dried pomegranate arils (P<0.05). Freeze-drying (FD) showed higher bioactive compounds, lower shrinkage, and better color quality than those of other samples. Ultrasound-assisted vacuum drying (UAVD) showed lower drying times, lower shrinkage, and higher bioactive compounds than vacuum drying (VD) and hot air drying (HAD). The ABTS, CUPRAC, and DPPH results were 34.53-63.71 μmol TE/g, 29.70-61.60 μmol TE/g and 64.82-93.69% DPPH radical scavenging activity, respectively. Also, the highest values of antioxidant capacity for all methods were obtained from the samples dried with FD followed by UAVD, VD, and HAD. The recovery of TPC in dried and fresh samples changed from 2.58% (fresh pomegranate) to 10.32% (vacuum-dried pomegranate). The recovery of TPC for freeze-dried samples (2.62%) was closest to the fresh ones and VD showed the highest TPC recovery. This study suggested that UAVD and VD should be used as alternative methods to HAD due to higher bioactive compounds retention, better color and surface quality, and higher recovery of bioactive compounds.

Ultrasound‐assisted vacuum drying as alternative drying method to increase drying rate and bioactive compounds retention of raspberry

This study aimed to determine the effect of different drying methods, namely hot air drying (HAD), vacuum drying (VD), ultrasound-assisted vacuum drying (USVD), and freeze drying (FD) on drying kinetic, total phenolic antioxidant activity, anthocyanin profile, in vitro-bioaccessibility of phenolic and color quality of raspberry samples. The drying time of the raspberry was 540, 720, and 1,140 min for USVD, VD, and HAD, respectively, indicating that USVD showed a significantly lower drying time than VD and HAD. The results of anthocyanin profile, TPC, CUPRAC, and DPPH analysis showed that FD had higher bioactive compound retention than other methods, followed by USVD. Cyanidin 3-O-sophoroside and Cyanidin 3-O-glucoside were found as the most abundant anthocyanin in raspberry samples. In the content of cyanidin 3-O-sophoroside, a loss of 78.33%, 15.41%, and 4.63% was observed in HAD, VD, and USVD, respectively. In vitro bioaccessibility of the VD and USVD were higher than FD and HAD. While the recovery value of TPC (%) was found for fresh raspberry as 3.09%, it was found as 6.79, 9.42, 8.46, and 5.58% for HAD, VD, USVD, and FD, respectively. Color quality was significantly affected by drying methods (p < .05), and USVD showed the lowest ∆E value. SEM analysis showed that less shrinkage and cell damage were observed in FD- and USVD-dried samples. This study suggested that USVD could be used as an alternative drying method since it showed lower drying time and shrinkage, higher bioactive compounds, and color retention than VD and HAD. Practical application Raspberry is a popularly consumed fruit rich in bioactive compounds such as anthocyanin and vitamin C. Raspberry is a fruit with a low shelf life, sensitive to microorganisms and enzyme activities due to its high nutritional content and water activity. Drying is one of the most widely used methods to increase the shelf life of raspberries. It is crucial to find a suitable drying method because the bioactive components, color, and physical structure may change during drying. In this study, the effects of four drying methods on the total bioactive components, anthocyanin profile, microstructural structure, color, and phenolic antioxidant in vitro bioaccessibility of raspberry fruit were investigated. The study contains original data.

Drying kinetics, total bioactive compounds, antioxidant activity, phenolic profile, lycopene and β-carotene content and color quality of Rosehip dehydrated by different methods

This study aimed to determine the effect of different drying methods namely, hot air drying (HAD), freeze-drying (FD), vacuum drying (VD), and ultrasound-assisted vacuum drying (USVD) on drying kinetic, total bioactive compounds, lycopene and β-carotene, phenolic composition and color quality of rosehip. Drying times of the rosehips for USVD, VD, and HAD were 180, 300, and 1140 min, respectively, indicating that USVD significantly reduced drying time of rosehip. The results of total bioactive compounds, lycopene and β-carotene, phenolic composition showed that FD resulted the highest bioactive compounds, followed by VD, USVD, and HAD. DPPH and CUPRAC results showed that FD dried samples showed highest antioxidant activity than fresh and all dried samples while HAD showed lowest antioxidant activity. USVD and FD exhibited a lower ΔE value than HAD and VD, indicating that they had similar color properties to the fresh sample. USVD resulted in lower drying time and color change than VD and HAD, while USVD showed lower bioactive compounds retention than VD. This study suggested that USVD could be used as an alternative to HAD due to its lower drying time and higher bioactive compound and color retention than HAD.

The experimental study and modelling the drying kinetics of mussels using ultrasound assisted vacuum drying

In the present study, chemical compositions, drying kinetics, quality parameters and energy consumptions for mediterranean or black mussel (Mytilus galloprovincialis) subjected to ultrasound assisted vacuum drying (UAVD) were analyzed between the range of 50–70 ​°C. During drying only falling rate periods were observed. Obtained conclusions demonstrated that the moisture content and drying rate were influenced by the ultrasound assisted vacuum drying method and the drying air temperature. The ultrasound assisted vacuum drying shortened the drying period and increased the effective moisture diffusivity (Deff). Drying led to a considerable increasing of protein and fat content. Six well-known thin layer drying models were compared with regards to coefficients of determination. The Alibas model was selected as the best one. The activation energy was calculated as 3.80 ​kW/kg. High “L∗" and low "ΔE" values were obtained for dried mussels. Using of ultrasound assisted vacuum drying technique resulted in very low energy consumption.

Modeling of hibiscus anthocyanins transport to apple tissue during ultrasound‐assisted vacuum impregnation

This study reports the mathematical modeling of hibiscus anthocyanins transport to apple tissues under various vacuum impregnation conditions (Control, VI 100, 250, and 500 mbar; ultrasound-assisted VI 100, 250, and 500 mbar). Azuara, Peleg, Diffusive, Z and L, and Weibull mathematical models were used to describe the water gain and anthocyanin gain's mass transfer kinetics. Azuara model successfully described the kinetic parameters of mass transfer during impregnation treatment. The equilibrium anthocyanin and water gain values predicted by the Azuara model varied between 38.4001–58.2536 and 24.0863–33.0245 mg/kg, respectively. Anthocyanin and water diffusion coefficients of the samples ranged between 0.406 × 10−9, −1.68 × 10−9, 0.117 × 10−9, and 0.715 × 10−9 m2/s, respectively. Ultrasound treatment increased moisture and anthocyanin gain during vacuum impregnation. At the end of the 30 min process, the highest anthocyanin content was determined as 38.85 mg/kg in samples treated ultrasound-assisted vacuum at 100 mbar. Novelty impact statement The studies on the modeling of bioactive components transport in the vacuum impregnation are limited although an increase is observed in the studies dealing with the enrichment of fruit and vegetable tissue with bioactive components. In the present study, Azuara model successfully described the kinetic parameters of mass transfer during impregnation treatment. In addition, ultrasound treatment increased anthocyanin content in the apple cubes during vacuum impregnation.

Effects of ultrasound-assisted vacuum tumbling on the oxidation and physicochemical properties of pork myofibrillar proteins

The present research aimed to investigate the effects of high-intensity ultrasound (HIU, 20 kHz, 0 W, 100 W, 300 W and 500 W)-assisted vacuum tumbling (UVT) for 60 min and 120 min on the oxidation and physicochemical properties of the pork myofibrillar proteins (MPs). Compared with the vacuum tumbling (VT) groups without the HIU assistance, the carbonyl content increased, while the total sulfhydryl (SH) content was reduced with the increase of HIU power and treatment time (P < 0.05). The reactive SH content was increased significantly after treated by UVT with 300 W compared with the VT group (P < 0.05) regardless of the treatment time. Similarly, the surface hydrophobicity (S0), the intrinsic tryptophan intensity, and the solubility in the UVT group (300 W) were remarkably higher than those of the VT group (P < 0.05). In contrast, the α-helix content and the particle size of MPs significantly decreased when the HIU power was at 100 W and 300 W (P < 0.05). The results suggest that UVT treatment could change the structure and physicochemical properties of MPs accompanied by protein oxidation.

Ultrasound-Assisted Vacuum Impregnation as a Strategy for the Management of Potato By-Products

One of the most important problems of the modern world is food wastage. The issue occurs at every stage of the food chain, requiring new sustainable production and processing technologies. The processing of production waste and making it a wholesome ingredient may be a good opportunity to promote more sustainable development. This study analyzes the process of enrichment of model by-product (irregular potatoes cubes) with a functional compound (ascorbic acid) through vacuum impregnation, with two experiments on variants of the process, standard (VI) and ultrasonic-assisted (UVI). The research covers complete processing, including the stage of preserving impregnated products by convective drying. The analysis includes the impregnation efficiency, drying kinetics, and energy consumption, and selected quality parameters of the material, namely color and water activity. Based on the results, ultrasound increased the impregnation efficiency, but the quantitative effect depends on the application period. Ultrasound had a positive effect on the kinetics and energy consumption of convective drying. Ultrasound did not reduce quality. The proposed technology may be useful during the processing of by-products.

Application of ultrasound-assisted vacuum impregnation for improving the diffusion of salt in beef cubes

The aim of this study was to investigate the effect of different vacuum impregnation (VI) conditions (Control, VI-250, VI-500, VI-750, US-VI-250, US-VI-500 and US-VI-750) on the salt gain (SG) and water gain (WG) kinetics of beef cubes. The cubes were immersed in brine solution (4 g NaCl/ 100 g solution) and salted at different levels of vacuum (250, 500 and 750 mbar) using VI method with and without ultrasound. The final moisture and salt contents of the cubes were 78.60% and 1.59%, respectively, and the samples were salted the fastest with US-VI-250. Five kinetic models were selected to evaluate the SG and WG kinetics, and Azuara model exhibited the best fit. In addition, the salt (Ds) and moisture (Dw) diffusion coefficients were in the range of 5.94–8.11 × 10−9 m2/s and 5.17–8.64 × 10−9 m2/s, respectively. It can be concluded that the ultrasound-assisted VI could shorten the brining time by improving the salt diffusion in beef cubes.