Freeze-dried Research Articles

Impact of Ultrasound Pre-Treatment on the Drying Kinetics and Quality of Chicken Breast-A Comparative Study of Convective and Freeze-Drying Methods.

Fresh meat has a limited shelf life and is prone to spoilage. Drying serves as a common method for food preservation. Non-thermal techniques such as ultrasound treatment (US) can positively affect the drying processes and alter the final product. The study aimed to evaluate the impact of US pre-treatment on the hot air (HA) and freeze-drying (FD) of chicken breast meat and the quality of the dried products. US pre-treatment had a varied impact depending on the drying method used. The contact US method extended the HA drying time (about 50%) but improved water removal during FD (about 30%) compared to the untreated samples. Both methods resulted in low water content (<8.3%) and low water activity (<0.44). While rehydration properties (RR) and hygroscopicity (H) were not significantly affected by US pre-treatment in HA drying (about 1.35% and about 1.1, respectively), FD noticed differences due to shrinkage and porosity variations (RR: 2.4-3.2%, H: 1.19-1.25). The HA-dried samples exhibited notably greater tissue shrinkage and a darker surface color than the FD meat. Ultrasonic processing holds substantial potential in creating dried meat products with tailored characteristics. Hence, meticulous consideration of processing methods and parameters is of utmost importance.

Pretreatment method for oxygen stable isotope ratio analysis of the sugar-rich fraction in fruit juice via isotope ratio mass spectrometry.

The oxygen stable isotope ratio (δ18O) of the sugar-rich fraction of fruit juice is important as a tracer of the geographical origin of raw material. This study sought to minimize the inter-day variation of δ18O attributable to the influence of water to accurately monitor geographical origin labeling. Two drying devices (freeze dryer and vacuum oven) were compared. Then, two humidity levels (normal and low humidity) at which the samples were placed after drying were compared. The low-humidity environment was constructed using a glove bag and pure argon gas. δ18O was measured using thermal conversion elemental analyzer/isotope ratio mass spectrometry. Improvements were made to the measurement method based on aforementioned analyses results, and the performance of the initial and improved methods was compared. δ18O of juice dried in a vacuum oven was 3.30‰ lower than that of juice dried in a freeze dryer. Moreover, δ18O of juice samples exposed to normal humidity was 3.74‰ lower than that of samples exposed to low humidity. The combined inter-day and intra-day standard deviation was reduced from 1.20‰ in the initial method to 0.42‰ in the improved method. This study describes a pretreatment method for δ18O measurement in the sugar-rich fraction of fruit juice with less inter-day variation, and it will be useful for monitoring geographical origin labeling.

Physicochemical characterisation of different drying methods on giant red shrimp (Aristaeomorpha foliacea) processing waste

AbstractThe effect of different drying methods (oven drying, fluid bed drying, and freeze drying) on the fatty acid composition, astaxanthin content, antioxidant activity, and colour values of giant red shrimp (Aristaeomorpha foliacea) processing wastes were investigated. These results showed that freeze drying was the most effective method in preserving the quality of shrimp processing waste (SPW), resulting in higher levels of EPA and DHA, astaxanthin content, antioxidant activity, and desired reddish colour characteristics compared to other methods. These findings highlight the potential of freeze drying as a suitable technique for converting SPW into high value products.

Physicochemical properties and volatile compounds of Rosa roxburghii fruit using different drying methods

To enhance the drying quality of Rosa roxburghii fruit, this study examined the effects of four methods: Natural Drying (ND), Hot Air Drying (AD), Heat Pump Drying (PD), and Vacuum Freezing Drying (FD). Fresh R. roxburghii fruit was used to assess drying characteristics, color, microstructure, active ingredient content, antioxidant activity, and volatile substances. Drying times for ND, AD, PD, and FD were 28, 7, 6, and 21 h, respectively, with the rate order PD > AD > FD > ND. AD samples showed superior water-binding capacity, solubility, and highest levels of flavonoids and polyphenols, enhancing antioxidant activity. FD samples had the best color performance and retained more intact cell structures and higher Vitamin C and polysaccharide levels. Volatile compounds were analyzed, revealing 45, 60, 61, and 50 compounds for ND, AD, PD, and FD, respectively. AD proved to be the most efficient method, providing optimal drying time, color, active ingredient content, antioxidant activity, and volatile components. This finding offers valuable guidance for selecting a drying method that preserves the quality of dried R. roxburghii fruit and suits industrial production.

Improved viability of probiotics by co-encapsulation of wheat germ oil under storage and gastrointestinal conditions: Effects of drying methods and wall composition

To improve the viability of probiotics during food storage and gastrointestinal digestion, this study developed solid microcapsules co-loaded with probiotics and wheat germ oil using W1/O/W2 emulsion pre-encapsulation, followed by spray drying (SD), freeze drying (FD) and spray freeze drying (SFD), respectively. The effects of drying methods and wall materials on the microstructure, physicochemical properties, storage stability, and gastrointestinal tolerability were highlighted. Firstly, all samples showed high encapsulation efficiency for probiotics (86%–99.2%) and wheat germ oil (72%–85%), low moisture content (2.8%–5.3%) and hygroscopicity (6.3%–11.6%), and wall materials exhibited structural stability during the drying process. The results of viable cell counts indicated that SFD caused more damage to bacterial cells than the other two drying methods, as evidenced by the total death of encapsulated probiotics within 90 days. In contrast, SD and FD encapsulated probiotics remained at 8.8–9.9 log CFU/g after 150 days of storage at 4 °C and 25 °C. Furthermore, the viability of probiotics in the co-encapsulated and pectin-added microcapsules was significantly enhanced in storage stability and simulated gastrointestinal digestion tests. Based on the above results, it was suggested that the co-encapsulation strategy of combining the W1/O/W2 structure and SD or FD to prepare microencapsulated powders can obtain probiotic products with high activity and high stability. Meanwhile, composite wall material (whey protein isolate and pectin) could enhance probiotics' protective effect and colonic targeted release behavior. In conclusion, the current research provides a valuable reference for the application of probiotics and functional oils in the food industry.

Computational and intelligence modeling analysis of pharmaceutical freeze drying for prediction of temperature in the process

Accurate temperature prediction is crucial for various scientific and engineering applications, yet it remains challenging due to the complex relationships between spatial coordinates and temperature variations. This study addresses this challenge by exploring advanced machine learning models to improve prediction accuracy, filling the research gap in optimizing predictive models for temperature estimation in freeze drying of pharmaceuticals. We employed Support Vector Regression (SVR), Poisson Regression (POR), and Adaptive Neuro-Fuzzy Inference System (ANFIS) models, each enhanced using the Cheetah Optimizer (CO), to estimate temperature based on spatial coordinates (X, Y, Z) in the domain of process. The methodology involved training and testing these models on a dataset comprising spatial and temperature data, with a focus on improving accuracy through optimization techniques. Validation of the models showed that the CO-SVR model outperformed the others, achieving an R2 score of 0.953, Mean Squared Error (MSE) of 9.893, and Mean Absolute Error (MAE) of 2.549. This represents a significant improvement over the CO-ANFIS model, which obtained an R2 of 0.863, MSE of 23.583, and MAE of 3.912. The CO-POR model showed the lowest predictive capability, with an R2 score of 0.753, MSE of 57.608, and MAE of 6.756. These findings underscore the effectiveness of the Cheetah Optimizer in enhancing the accuracy of SVR models for temperature prediction, suggesting its potential for broader applications in predictive modeling where accuracy is paramount.

Identification and formation of key aroma-active compounds in red jujube as affected by different processing methods

Processing methods significantly affect the aroma characteristics of red jujube; however, few studies have explored how. Gas chromatography–tandem mass spectrometric detection, gas chromatography–olfactometry, relative odor activity value and quantitative descriptive analysis were used to investigate the aroma changes of red jujube during typical processing (freeze drying, baking, frying and steaming); furthermore, the formation of aroma-active compounds in processed red jujube was predicted based on untargeted metabolomics. After freeze drying, the total aroma content increased by 0.90 %, while it decreased by 51.59 %, 74.11 % and 78.74 % after baking, frying and steaming, respectively. In addition, ethyl esters dominated the sweet and fruity notes in freeze-dried red jujube, which were formed via combination of fatty acids metabolism, pyruvate metabolism and amino acid catabolism. (E,E)-2,4-Decadienal derived from fatty acid oxidation dominated the fatty note in fried red jujube. 2-Ethyl-3,5-dimethylpyrazine formed via the Maillard reaction dominated the roasty notes of baked red jujube.

Viability and Survival of Lactobacillus casei Encapsulated with Whey, Sucrose and Maltodextrin Using Freeze-Dried Technique

Lactobacillus casei bacterium in probiotic products and in the human digestive tract could be decreased so that encapsulation preserved techniques need to protect the viability of Lactobacillus casei. The aimed of this study was to determine the ability and survival of L.casei with cryoprotectant materials that consist of a combination of whey with sucrose and whey with maltodextrin using freeze drying technique. The study design used was a complete randomized design consisting of five treatments with two replications which were control; whey 10% with sucrose 10%; whey 10% with maltodextrin 10%; whey 20% with sucrose 10%; and whey 20% with maltodextrin 10%. The anova test α = 0.05 was conducted, if significantly different than continued with a Duncan test. The results showed Lactobacillus casei encapsulated with whey 20% (v/v) and sucrose 10% (w/v) had the highest viability to the freeze drying process and during 28 days of storage at low temperatures (4°C) with the viability of each amounted to 92.66% and 90.38%. Lactobacillus casei with whey 20% (v/v) and maltodextrin 10% (w/v) was the best survival to 0.5% bile salts and low pH (pH 2). The best result was Lactobacillus casei with whey 20% (v/v) and maltodextrin 10% (w/v) to encapsulated and protected the bacterium.

The Use of Beetroot Juice as an Impregnating Solution to Change Volatile Compounds, Physical Properties and Influence the Kinetics of the Celery Drying Process.

The effect of different methods of drying celery root enriched with beet juice by vacuum impregnation (VI) was studied. The process of convection drying, vacuum drying and freeze drying was carried out. Compared to dried indigenous celery, dry impregnated tissue was characterized by lower values of dry matter, L* and b* color parameters, as well as higher values of water activity, density and a* color parameter. In addition, VI reduced the drying time. Forty Volatile Organic Compounds (VOCs) were found in celery, while fifty-one VOCs were found in the profile of celery with beetroot juice. The innovative method of vacuum impregnation made it possible to produce a new type of product with changed properties and a variable VOCs profile. The best fit of the drying process kinetics was achieved by using the logistic model. Increasing the temperature during convection drying resulted in shorter drying time, increased values of dry matter, reduced the water activity value and altered VOCs.

Drying strategies for maximizing polyhydroxybutyrate recovery from microalgae cultivated in a raceway pond: A comparative study

Polyhydroxybutyrate (PHB) derived from microalgae are considered a promising alternative bioplastic material to replace synthetic plastics. This study evaluated the effects of various drying techniques (sun, freeze, oven and air drying) on PHB recovery from microalgae. Freeze drying recovered the maximum PHBs (6.2%) followed by sun drying (5.2%), air drying (2.3%), oven drying (2%), and the lowest in wet biomass (1.2%). The most energy-intensive drying method was freeze drying (26.83 kW) followed by oven drying (3 kW) while the other methods did not require energy. The minimum time requirement for drying was oven drying (6 h), followed by freeze drying (24 h), sun drying (48–72 h), and air drying (96–120 h) while wet biomass did not require time. In terms of PHB yield per unit time, oven (0.33%/h) is a more effective drying technique than freeze drying (0.25%/h) which produces 24.24% higher PHB yield per unit time. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed PHB structure and thermal stability up to 300 °C from dried biomasses compared to wet biomass at 200 °C. This study indicated that drying techniques significantly influence the PHB recovery from microalgae biomass. Findings also revealed that the oven dried technique can be efficiently scaled up for PHB recovery.

Enrichment of White Chocolate with Microencapsulated β-Carotene: Impact on Quality Characteristics and β-Carotene Stability during Storage.

This study developed functional white chocolate enriched with free (WC-F) and encapsulated β-carotene using whey protein isolate (WPI) and pullulan (PUL) blends through spray drying (WC-SP), freeze drying (WC-LP), and coaxial electrospinning (WC-EL). The thermal properties, rheological properties, hardness, and color of the chocolates were evaluated, and the stability of β-carotene was monitored over 4 months at 25 °C. No significant differences were found in melting profile temperatures among samples; however, WC-LP and WC-EL exhibited higher melting energies (30.88 J/g and 16.00 J/g) compared to the control (12.42 J/g). WC-F and WC-SP showed rheological behaviors similar to those of the control, while WC-LP and WC-EL displayed altered flow characteristics. Hardness was unaffected in WC-F and WC-SP (7.77 N/mm2 and 9.36 N/mm2), increased slightly in WC-LP (10.28 N/mm2), and decreased significantly in WC-EL (5.89 N/mm2). Over storage, melting point, rheological parameters, and hardness increased slightly, while color parameters decreased. β-carotene degradation followed a first-order reaction model, with degradation rate constants (k) of 0.0066 day-1 for WC-SP, 0.0094 day-1 for WC-LP, and 0.0080 day-1 for WC-EL, compared to 0.0164 day-1 for WC-F. WC-SP provided the best β-carotene retention, extending the half-life period by 2 times compared to WC-F (126.04 days vs. 61.95 days). Practical implications: The findings suggest that WC-SP, with its superior β-carotene stability, is particularly suitable for the development of functional confectionery products with extended shelf life, offering potential benefits in industrial applications where product stability is crucial. Future research directions: Further studies could explore the incorporation of additional bioactive compounds in white chocolate using similar encapsulation methods, as well as consumer acceptance and sensory evaluation of these enriched products.

Effects of freeze–thaw pre‐treatment with different freezing methods on the microwave freeze drying of carrots

SummaryThree freeze–thaw (FT) pre‐treatments using different freezing methods that freezing at −80 °C (FT‐80), freezing at −25 °C (FT‐25) and vacuum freezing (VFT) were used for carrot slices, the effects and mechanisms of FT pre‐treatment on the drying characteristics and product quality of carrots during microwave freeze drying (MFD) were studied. The results showed that FT pre‐treatment under different freezing methods affected the water state of carrots, resulting in varying degrees of moisture loss and shortening drying time by 14.3% to 42.8%. VFT treatment caused the greatest water loss (35.33%) during FT and significantly increased the effective moisture diffusivity in the MFD process. FT treatments did not cause any significant degradation in the colour of the carrots. The VFT and FT‐80 treatments resulted in an elevated rehydration ratio, increased crispiness of MFD carrots and products with a porous microstructure and higher porosity. In contrast, the FT‐25 treatment led to a decrease in porosity due to destructive damage to the carrot cell structure. However, this damage favoured the extractability of carotenoids, resulting in a higher carotenoid content than the other treatments. This study provides a theoretical foundation for the practical implementation of FT pre‐treatment using various freezing methods on fresh foods prior to drying. It is recommended to employ VFT pre‐treatment before MFD due to its efficiency and effectiveness.

Evaluating the feasibility of powder milk production by pulse spray drying: An approach on sensory properties, toxicological assessment, and microbial inactivation

The potential of a new spray drying technology (pulse spray drying, PSD) was explored in drying milk, using two outlet temperatures. Sensory attributes, instrumental color properties, and volatile compounds were examined. Additionally, the effect of PSD on the food's chemical safety was measured by CALUX® bioassays. For these approaches, milk was also dried by conventional spray drying (SD) and lyophilization (LYO). Finally, the impact of PSD on the microbiological load was investigated using Pediococcus acidilactici ATCC 8042, as a non-pathogenic surrogate of enteric pathogens. In sensory analysis, reconstituted PSD samples were scored with higher color, odor, and flavor intensities than LYO and SD. Volatiles like γ-hexalactone, acetic acid, and ethyl acetate could have contributed to these particularities. Accordingly, instrumental color revealed differences between the four treatments, showing a more evident yellowish coloration and higher saturation in PSD milk. Cytotox, PXR, and p53 CALUX® results in PSD samples ranged from 0.11 to 0.21 μg Tributyltin acetate eq./g, 0.30–0.51 μg Nicardipine eq./g, and were under quantification limit, respectively. These findings indicated that PSD does not pose an increased toxicological risk compared to other drying technologies. Viability results of Pediococcus acidilactici during PSD showed that the higher the outlet temperature, the lower the cell viability. In conclusion, all data raised in this study evidenced that PSD could be used in milk drying without compromising its quality and safety. Industrial relevanceConsidering the low energetic consumption described in several works, pulse spray drying could be a promising approach for the food sector. In addition, it may play a relevant role in overcoming the limitations of conventional spray dryers in terms of viscosity. The results obtained in this study are one of the first in this field and show the feasibility of milk powder production without compromising its quality and safety.

Automated particle inspection of continuously freeze-dried products using computer vision

The pharmaceutical industry is progressing towards more continuous manufacturing techniques. To dry biopharmaceuticals, continuous freeze drying has several advantages on manufacturing and process analytical control compared to batch freeze-drying, including better visual inspection potential. Visual inspection of every freeze-dried product is a key quality assessment after the lyophilization process to ensure that freeze-dried products are free from foreign particles and defects. This quality assessment is labor-intensive for operators who need to assess thousands of samples for an extensive amount of time leading to certain drawbacks. Applying Artificial Intelligence, specifically computer vision, on high-resolution images from every freeze-dried product can quantitatively and qualitatively outperform human visual inspection. For this study, continuously freeze-dried samples were prepared based on a real-world pharmaceutical product using manually induced particles of different sizes and subsequently imaged using a tailor-made setup to develop an image dataset (with particle sizes from 50μm to 1 mm) used to train multiple object detection models. You Only Look Once version 7 (YOLOv7) outperforms human inspection by a large margin, obtaining particle detection precision of up to 88.9% while controlling the recall at 81.2%, thus detecting most of the object present in the images, with an inference time of less than 1 s per vial.

Equivalence of freeze-dried and liquid-frozen formulations of MVA-BN as smallpox and mpox vaccine

ABSTRACT Modified Vaccinia Ankara Bavarian Nordic (MVA-BN) as a smallpox and mpox vaccine has been approved in its liquid-frozen (LF) formulation in the US, Canada, and EU. A freeze-dried (FD) formulation may offer additional benefits, such as a longer shelf life and reduced dependence on cold chain storage and transport. In a phase 2 clinical trial, 651 vaccinia-naïve participants were vaccinated with two doses of MVA-BN LF or FD, 4 weeks apart. The objectives were to compare MVA-BN FD with LF in terms of vaccine-induced immune responses, safety, and reactogenicity. Non-inferiority of the immune response was assessed by the 95% CI of the geometric mean ratios. Both formulations induced robust vaccinia-specific humoral and cellular immune responses. At peak humoral responses (Week 6), geometric means of total antibody titers were 1096 (95% CI 1013, 1186) from the FD group and 877 (95% CI 804, 956) from the LF group, achieving the primary endpoint of non-inferiority of MVA-BN FD compared to MVA-BN LF. At peak cellular responses (Week 2), geometric means of T cell spot forming units were 449 (95% CI 341, 590) from the FD group and 316 (95% CI 234, 427) from the LF group. Both formulations of MVA-BN were well tolerated, with similar unsolicited AEs and solicited systemic reactions in both groups but slightly more local reactions in the FD group. No vaccine-related serious adverse events (SAEs) or vaccine-related AE of special interest were reported. The FD formulation of MVA-BN was shown to be equivalent to MVA-BN LF.

Hot air-assisted radio frequency drying of orange slices: Drying behavior and product quality.

This research aimed to assess the hot air-assisted radio frequency drying (HA-RFD) of orange slices to evaluate the possibility of producing high-quality dried orange slices and overcome the problem of the long drying time and the high energy consumption. The effect of electrode distance (60, 70, and 80mm) and number of slices (1-3 slices; 4mm thickness per slice) on the HA-RFD of orange slices was evaluated. Orange slices in three layers with a total thickness of 12mm and an electrode gap of 70mm were picked to dry the orange slices in the shortest time. The quality of orange slices dried with HA-RFD was compared with those of HA-dried (HAD) and freeze-dried (FD) samples. HA-RFD allowed a 67% decrease in the time of drying of the orange slices (from 1170 to 390min) when compared to HAD. Total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and color values were affected by the drying technique. HA-RFD showed higher TPC, TFC, and antioxidant activity than HAD. The FD samples showed the highest TPC (928mgGAE/100gdw), TFC (200mgrutin/100gdw), and antioxidant activity (67.58%). Moreover, the samples dried with HA-RFD resulted in the least color change in comparison to HAD and FD samples. Regarding vitamin C, FD samples were the best, followed by HA-RFD and HAD, respectively. Considering the final product quality, and the characteristics of drying techniques, especially drying time and drying rate, HA-RFD proved to be an alternative technique to the HAD for producing dried orange slices. PRACTICAL APPLICATION: HA-RFD was applied for the first time as an alternative technology to dry orange slices. The quality of orange samples dried by HA-RFD was compared with samples that dried by HAD and FD. The results indicated that the HA-RFD technique is a good method to dry orange slices by considering the drying characteristics and the final product quality.

The freeze-drying performance under pressures from 1.325 to 101.325 kPa

The low drying rate is the main limitation of atmospheric freeze drying. The drying rate depends on the balance between heat and mass transfer. Among the process variables, air pressure changes have the opposite effects on heat and mass transfer simultaneously. The increase in pressure favors heat transfer but hinders mass transfer. Therefore, a conjugate model was proposed and validated to quantitatively investigate the heat and mass transport characteristics of lamellar products during freeze-drying in a tunnel under different pressures (1.325–101.325 kPa). To describe the effects of air pressure, the Navier-Stokes equations of the external fluid were coupled with the adsorption-sublimation model. Results show the regulation of transfer resistance values and drying rate with moisture content during the drying process, indicating that freeze-drying is the external heat transfer control at first, then the internal mass transfer control, and eventually, the heat transfer promotion can accelerate the process. The optimal constant pressure value was found to be 5.325 kPa, with the shortest drying time (17.3 h). It has been demonstrated that freeze drying employing a specific laddering-controlled strategy, offers the benefit of reducing drying time in comparison to the use of optimal constant pressure; however, the impact was not remarkable.

Impact of different pre-treatments and drying methods on the physicochemical properties, bioactive compounds and antioxidant activity of different tomato (Solanum lycopersicum) cultivars

A green pre-treatment approach, microwave (MW) and ultrasound (US), along with drying methods [hot air (HA) and freeze-drying (FD)], was assessed for colour properties, phenolics, carotenoid components and antioxidant activity DPPH, ABTS, FRAP assays of three tomato cultivars (Zzx171, Zzx162 and Zzx65). All three cultivars showed a reduced colour difference (ΔE) after US-FD. The US-FD method retained higher levels of total carotenoids, lutein, β-carotene, lycopene and antioxidant activity in all cultivars than other methods. While US-HA drying retained the highest level of total phenolic content, chlorogenic acid, 4-O-caffeoylquinic acid, rutin, protocatechuic acid and ABTS•+ scavenging activity in powders of all cultivars. ‘Zzx162’ is best suited for US-FD to produce tomato carotenoids-rich functional powder. Powders of ‘Zzx162’ showed the highest lycopene (14.40 mg/g), β-carotene (6.13 mg/g), and ABTS•+ scavenging activity (8.37 SC50 mg/mL). While ‘Zzx162’ with US-HA produced powders rich in chlorogenic acid (58.48 mg/100 g) and rutin (50.33 mg/100 g). These findings suggest that ultrasound pre-treatment is the preferred technology for developing functional tomato powder.

Physicochemical and bioactive characterization of pink guava pulp microcapsules prepared by freeze-drying using coffee mucilage as a wall material

This study investigated the potential of coffee mucilage (CM), a readily available coffee industry byproduct, as a wall material for the microencapsulation of pink guava pulp via freeze-drying (FD). Microcapsules with varying wall compositions incorporating powdered coffee mucilage, maltodextrin (MD), or a combination of both (FD-CM/MD) were developed and characterized using techniques such as FT-IR spectroscopy, SEM, TGA/DSC, and zeta potential analysis. The retention of bioactive compounds was assessed using total phenolic content, antioxidant capacity and carotenoid analyses. Results revealed that the incorporation of powdered coffee mucilage significantly influenced the physicochemical properties of the microcapsules, resulting in larger particle sizes and less rough surface morphologies compared with maltodextrin-based formulations. Notably, FD-CM microcapsules exhibited a thermal stability (Tg ≈ 50 °C) and retention total polyphenols of 30.19 ± 5.26 mg GAE/g dry weight (DW) and carotenoids of 5.50 ± 0.29 mg β-carotene/100 g DW, which can be attributed to the protective effects and inherent antioxidant capacity of 91.85 ± 9.93 μmol Trolox Equivalents/g DW in the coffee mucilage matrix. While influencing the color attributes, all microcapsule formulations retained a commercially appealing (hab = 79.80 ± 0.06) red-yellow hue. This study demonstrated the potential of powdered coffee mucilage as a sustainable and effective encapsulating wall material for enhancing the stability and bioavailability of bioactive compounds in food products.

An integrated study of quality variations for Eucommia ulmoides Oliver staminate flower processed with different drying treatments by untargeted metabolomics coupled with chemometrics

Eucommia ulmoides Oliver staminate flower (EUF) has been increasingly served as a potential feedstock for nutraceuticals. An integrated approach of untargeted metabolomics based on gas chromatography hyphenated with mass spectrometry (GC-MS) and ultrahigh performance liquid chromatography hyphenated with high resolution mass spectrometry (UHPLC-HRMS) coupled with advanced chemometric method was applied to investigate the metabolic variations of EUF obtained from various drying treatments. The metabolomics analysis was conducted automatically in our newly developed data analysis platform AntDAS. Chemometric methods were further used to provide additional insight into the chemical differences of EUF. 34 volatile and semi-volatile as well as 89 nonvolatile compounds were identified and demonstrated significant differences among diverse drying treatments. Moreover, among which 27 volatile and semi-volatile compounds along with 35 nonvolatile compounds were verified qualitatively by standards. The results revealed that shade drying was more effective for the preservation of volatile and semi-volatile substances, including sugars and vitamins. Freeze drying was conducive for preserving nonvolatile compounds, such as iridoids, flavonoids, and organic acids. The content of alcohols, amino acids, and nucleosides was abundant in heat-pump drying, oven drying, and hot air drying, respectively. In addition, hot air, heat pump, and oven drying methods showed a moderate level of the majority of bioactive components and suitable for industrialization process. This work potentially highlights the possibility of using chemometrics in conjunction with untargeted GC-MS and UHPLC-HRMS analysis for quality assessment of EUF.