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In contrast to the freeze-drying process, the rehydration process of freeze-dried foods remains unclear. This study investigated the rehydration of freeze-dried soybean curd, also known as tofu, and elucidated its breakage mechanism during rehydration, which impairs texture. The rehydration of freeze-dried tofu was observed at different water temperatures (20, 40, 70, and 100 °C), with the required rehydration time found to decrease with increasing water temperature. Furthermore, tofu was found to absorb water faster in cracks formed during production than in the porous body. Crack expansion was observed only in hightemperature water, leading to breakage of the tofu. Environmental scanning electron microscopy revealed that tofu expanded when a sufficient amount of water was absorbed. Accordingly, crack expansion in hightemperature water is attributed to the stress concentration at the tip of the crack, which is caused by differences in the rehydration rate and resulting stiffness between the porous body and cracks. [ABSTRACT FROM AUTHOR]

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[Display omitted] • 1. Utilized sodium alginate and κ-carrageenan to enhance fucoxanthin stability. • 2. Encapsulated-FX chunks kept structure, flavor, and antioxidant activity after 7 d. • 3. Sodium alginate and pectin, key in chunks, enhanced FX stability during digestion. • 4. Provided a novel approach for producing stable, nutritious seaweed-based snacks. Carotenoids, recognized for their antioxidant and anti-aging properties, are commonly used in functional foods. To enhance the application of fucoxanthin (FX) in the food industry, this study employed the ion gel method for encapsulating FX and combined it with raw materials such as Undaria pinnatifida homogenate and apple pieces to create freeze-dried crunchy chunks. The study evaluated the effects of encapsulated-FX on the functional and structural characteristics of the Undaria pinnatifida and apple freeze-dried chunks over accelerated storage period under high temperature and humidity. Various analyses were conducted, including physicochemical properties, texture analysis, color evaluation, sensory assessment, and simulated digestion analysis. The results demonstrated that the FX-rich freeze-dried crunchy chunks exhibited favorable structural properties and appealing flavor. Notably, after the accelerated storage period, the encapsulated-FX maintained significant antioxidant activity, along with excellent thermal and light stability, indicating high storage stability. Additionally, the main ingredients, sodium alginate (SAA) and pectin (PE), significantly enhanced the stability of FX during in vitro digestion. This study provided a straightforward approach for producing freeze-dried snack foods rich in stabled-FX, contributing to the diversity of value-added algae products. Furthermore, it laid a theoretical foundation and reference for the future development of nutritional products. [ABSTRACT FROM AUTHOR]

Freeze-drying technology is an interdisciplinary and complex technology, combined with freezing and vacuum drying, It has become an important technology for heat-sensitive drugs and food preservation. Freeze-dried foods are classified into meat, vegetables, fruits, fungus, and micro-powders, etc. In this paper, the definition, principle, steps, advantages and disadvantages of freeze-drying are summarized, and the research progress of freeze-drying in food industry in recent years is reviewed, including the technological parameters and influencing factors. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the research endeavour was to evaluate the powder properties of freeze dried and spray dried beet-root powders. The physical, proximate, color and functional properties such as water activity, wettability, solubility and hygroscopicity were studied. From the comparative analysis between freeze and spray dried beet root powder, better results were found for freeze-dried samples in terms of color, wettability and hygroscopicity. Freeze-dried samples required a longer amount of time to obtain into powder form as compared to spray dried samples. Whereas the solubility and water activity values were found slightly higher in spray dried samples as compared to freeze dried samples. The proximate analysis, such as crude fiber, crude fat, ash and carbohydrate values recorded better result for freeze dried samples as compared to spray dried samples. It can be concluded from this study that the beet root, when dried in the freeze drying process, has better results as compared to the spray drying process. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate the effect of a highly interconnected porous microstructure on the quality of rehydrated tomatoes by (a) designing a freeze‐dried cycle that ensure product integrity (i.e., no collapse, no puffing) (b) characterizing both freeze‐drying and rehydration kinetics. Fresh tomatoes were first freeze‐dried and subsequently rehydrated to get generate kinetics data. Afterwards, six thin‐layer drying models and four rehydration models were fitted using regression analysis to the experimental data. The goodness‐of‐fit was evaluated according to root mean squared error, adjusted R2, Akaike information criterion, and Bayesian information criterion. The most accurate representations of the system kinetics were observed using the Page model for freeze‐drying and the exponential and Weibull models for rehydration. Rehydration capacities and equilibrium moisture contents of the rehydrated samples were found to increase with temperature, and the corresponding activation energy values were calculated. Practical applications: Freeze‐dried porous microstructures can enhance water absorption and transport, contributing to restore the fresh product functional properties and leading to higher quality rehydrated products, especially in highly heat‐sensitive food products as vegetables and fruits. The use of mathematical models to (a) design freeze‐drying cycles and (b) characterize and/or predict drying and rehydration kinetics in cellular freeze‐dried microstructures is then key for processing and optimization of convenience and ready‐to‐eat foods, which represents the main application of dried foods/powders and also a growing market. This approach to the manufacture of freeze‐dried products also presents potential to set the basis of an alternative decentralized supply scenario for high‐quality dried products, where freeze‐dried foods will be manufactured and shipped and finally rehydrated closer to the consumption point. [ABSTRACT FROM AUTHOR]

Freeze-drying is a common method to prepare dried starter cultures with high stability and a long storage time. However, the bacterial cells suffer varying degrees of damage during the freeze-drying process. This study aimed to provide an effective strategy to improve the survival rate of Lactobacillus curvatus and to explore its potential protective mechanisms. The survival rates of bacterial cells in different cryoprotectants before and after freeze-drying were measured using the plate count method. The protective effects of composite cryoprotectants on bacterial cells were investigated from multiple perspectives, including key enzyme activities, the internal morphology of bacterial cells, and cell membrane integrity. Results showed that the freeze-drying survival rate of bacterial cells in the composite cryoprotectants consisting of trehalose, oleic acid and skimmed milk (85.38%) was significantly improved compared to that in PBS solution (2.04%). The addition of composite cryoprotectants could reduce damage to the cell wall and cell membrane, maintain the normal morphology of bacterial cells and cell membrane integrity, and improve key enzyme activities (lactate dehydrogenase, pyruvate kinase and ATPases) during the freeze-drying process. The viability of freeze-dried cultures was also monitored at different temperatures during storage, and the cell survival of freeze-dried cultures at −20 °C was the highest, reaching 61.13%. The findings obtained in this work offer a new method to improve the viability of Lactobacillus curvatus after freeze-drying, and may promote the wide use of freeze-dried cultures in the food fermentation industry. [Display omitted] • The cell viability of freeze-dried cultures with composite cryoprotectants consisting of trehalose, oleic acid, and skimmed milk reached 85.38%. • The freeze-dried cultures with composite cryoprotectants showed higher activities of key enzymes than those in PBS solution. • The cell membrane integrity was maintained by the addition of composite cryoprotectant. • Dried cultures had a 61.13% survival rate at −20 °C for 3 months of storage. [ABSTRACT FROM AUTHOR]

Mushrooms are health foods due to their nutritional values and antioxidant properties. This study investigated chemical properties, total phenolic content (TPC), antioxidant activities (2, 2-diphenyl-1-picrylhydrazyl; DPPH and 2, 2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid); ABTS) and selected phenolic acids from five different tray-dried and freeze-dried mushrooms (Pleurotus ostreatus, Pleurotus pulmonarius, Schizophyllum commune, Volvariella volvacea and Lentinus edodes). The extracts were prepared using methanol and hot water extractions. The results revealed that V. volvacea had the highest protein (28.70%) and ash (9.48%) contents. There were significant differences among some tray dried and freeze dried mushrooms regarding TPC, DPPH and ABTS. However, tray drying tended to improve TPC, DPPH and ABTS in P. ostreatus, P. pulmonarius and L. edodes. Among five mushroom species, both methanol and hot water extractions of V. volvacea had the highest TPC, DPPH and ABTS values but there were no significant differences between mushrooms prepared using tray drying and freeze drying. Moreover, the yield and contents of gallic acid and p-hydroxybenzoic acid from the hot water extracts were higher than from the methanol extracts. Therefore, tray-dried V. volvacea had the most potential as a natural antioxidant and could be used as a functional ingredient in healthy food products. [ABSTRACT FROM AUTHOR]

Highlights • Cookies with Japanese quince fruits (JQF) had high antioxidative potential. • Presence of acetic acid in enriched cookies intensified acidic and citrus aroma. • Stored cookies were rich in hydrocarbons, including newly generated ones. • Addition of JQF enhanced microbiological safety of stored cookies. • Consumers preferred cookies containing 1 and 1.5% JQF to those containing 6 or 9%. Abstract The study aimed at assessing effects of freeze-dried Japanese quince fruit (FJQF; 0–9%) added to cookies to improve their antioxidant attributes during storage, sensory and volatile characteristics and acceptability by consumers. Cookies containing FJQF had 2-3.5-fold higher radical scavenging activity and exhibited less secondary lipid oxidation products compared with the control cookies. Enriched cookies had higher contents of volatile hexanal, heptanal, octanal, 2-heptenal, (E) than control cookies. Acetic acid dominated in the volatile profile of enriched cookies (ranging 7.05–23.37%), hence intensities of acidic and citrus aroma were scored high. Cookies stored for 16-weeks showed increased amounts of hydrocarbons as compared with fresh cookies and new hydrocarbons were also generated, which were not detected in fresh cookies. The consumer panel indicated a higher preference for cookies containing 1.0 and 1.5% FJQF than those containing 6.0 and 9.0%. [ABSTRACT FROM AUTHOR]

Abstract The effect of a tailored structure on sorption properties and phase transition temperatures of freeze-dried gels with low-methoxyl pectin and a mixture of xanthan gum and locust bean gum was investigated. Gels were aerated for 3, 5, 7 and 9 min which together with hydrocolloid type diversified the porous structure of samples. Shrinkage value was in the range 3.5–11.9% for gels with low-methoxyl pectin, and higher for samples with the mixture of xanthan gum and locust bean gum (34.1–40.5%). This structure had impact on the sorption kinetics and isotherms as well as phase transition temperatures. The larger free spaces and smaller shrinkage value lowered the sorption properties. Samples with xanthan gum and locust bean gum aerated by 5 min had the lowest sorption properties related to their structure. The GAB model fitted well with moisture sorption isotherms. The course and shape of DSC curves were affected by the type of gel ingredients, whereas the aeration time did not have any impact on them. Highlights • Hydrocolloid type and aeration time influenced on structure of freeze-dried gels. • The structure influenced on sorption kinetics of samples, less on isotherms. • The type of gel ingredients has an influence on course and shape of DSC curves. • The aeration time of samples has no influence on phase transitions of gels. • Low-methoxyl pectin gels had the best physical properties. [ABSTRACT FROM AUTHOR]

Abstract In this study, the impact of a pulsed electric field (PEF) treatment on the final quality of freeze-dried apples was investigated. The PEF treatment has been performed at an electric field intensity equal to 1.07 kV/cm and a specific energy input of 0.5, 1 and 5 kJ/kg. The samples were freeze-dried (without a separate pre-freezing step) at varying temperatures (set on 40 °C and 60 °C) and pressures (0.1, 0.25 and 1 mbar). The quality of dried material was evaluated by the analysis of residual moisture content, macro- and microscopic properties, colour, the total content of phenolic compounds and the antioxidant activity as well as texture and acoustic properties. It was found that the residual moisture content of PEF treated samples was reduced by up to ∼82% in comparison to the intact tissue. For electroporated samples, a good preservation of macro-shape, an inhibition of shrinkage and the development of large pores were observed. The PEF treated material exhibited a higher total phenolic content, but a smaller antioxidant activity. Mechanical and acoustic analysis showed a higher crunchiness and brittleness for PEF-treated tissue, whereas untreated tissue was characterised by a harder and rather crackly texture. Highlights • Application of PEF before freeze-drying preserved the shape of apples. • PEF pre-treated freeze-dried apples exhibited better crunchiness. • Freeze-dried apples subjected to PEF exhibited higher total polyphenol content. [ABSTRACT FROM AUTHOR]

This study aimed to assess and compare the nutritional composition between unripe and ripe freeze-dried Terung Asam from Sarawak. Terung Asam was checked for its maturity upon collection. Whole fruits were freeze-dried and used for proximate analyses. The redness/greeness (a*) of unripe and ripe fresh Terung Asam used in this study were -14.20 ± 3.11 and 12.57 ± 1.60 respectively. The moisture content of unripe fresh Terung Asam was significantly higher than ripe fresh Terung Asam (p < 0.05). There were statistically significant differences in crude protein (p < 0.05), crude fat (p < 0.05), ash (p < 0.05) and crude fibre (p < 0.001) between unripe and ripe freeze-dried Terung Asam (UFTA and RFTA respectively). RFTA had higher crude fibre (19.87 ± 0.68g/100g) and ash (6.20 ± 0.18g/100g) than UFTA (13.86 ± 0.58g/100g crude fibre, 5.43 ± 0.12g/100g ash). In contrast, UFTA was higher in protein (10.77 ± 0.30g/100g) and fat (0.74 ± 0.05g/100g) than RFTA (9.43 ± 0.40g/100g crude protein, 0.48 ± 0.08g/100g fat). The results of this study suggested that whole fruits of UFTA and RFTA were good source of crude protein, crude fibre and mineral. The data gathered from this research can contribute to the body of knowledge of this underutilized indigenous fruit as well as becoming useful for future product development using Terung Asam. [ABSTRACT FROM AUTHOR]

Walnuts are appreciated all around the world by consumers and food industries because of their different and positive properties including flavouring, texturizing and nutritional qualities. Walnut paste production and use are commonly associated to confectionery or traditional products but may find space in different innovative foods, as fat replacer and functional component. The aim of this work was to increase the nutritional value of walnut paste and, at the same time, limit its oxidative degradation by developing a freeze-drying process with addition of polysaccharide matrices including dietary fiber. The effects of different formulations and technological treatments on product stability were evaluated. Shelled walnuts were roasted at 165 °C for 15 minutes, grinded, and refined; the obtained walnut paste was mixed with betaglucan, inulin and pectin, singly or combined with tragacanth gum and DE12 maltodextrin. The different formulations were added to water, emulsified and dehydrated by freeze-drying. Lyophilized samples were finally stored at 60 °C for 15 days. Walnut paste, samples just after lyophilization, and lyophilized samples after storage were evaluated in terms of moisture, peroxide number, acidity and pH, conjugated dienes and trienes, total phenols and tocopherols. Further analyses (color, 410 and 420 nm absorption, and total phenols content after ethanol precipitation) were carried out on freeze dried samples before and after storage. The results showed that the freeze-drying process affected the nutritional profile of the walnuts, limiting the onset of oxidative phenomena. After storage the content of total phenols and tocopherols was significantly higher already in the freshly lyophilized walnut paste, compared to the untreated one. The addition of polysaccharide compounds aided to preserve total phenols. However, when betaglucan, inulin, or pectin were individually included, a significant depletion of tocopherols was observed. Maltodextrin and tragacanth gum played a fundamental role in maintaining high levels of both total phenols and tocopherols. Nevertheless, formulations including also dietary fiber were slightly more oxidized. Among them, the inclusion of betaglucan provided the overall best results. [ABSTRACT FROM AUTHOR]

In this work, a novel procedure is presented for the measurement and prediction of pore size distribution of freeze-dried solutions in vials. A method based on segmentation is proposed for determining the size of the pores left by ice crystals, using images obtained by scanning electron microscopy. The original ice crystal size distribution is also predicted using a mathematical model based on balance equations. The model predictions and the results of the segmentation technique show a fairly good agreement. The proposed procedure could be used to efficiently estimate the resistance to mass transfer during drying and hence optimize the freeze-drying process. [ABSTRACT FROM AUTHOR]

Abstract In the present work, we investigated the effects of powder dry-heating parameters on whey protein foams stability, especially against drainage. To this aim, whey protein isolate solutions were prepared at various pH (3.5, 5.0, 6.5), with or without a prior dialysis step to reduce the lactose content, freeze-dried, adjusted to various levels (0.12, 0.23, 0.52) of powder water activity a w and dry-heated at 70 °C for up to 125 h. Protein solutions were then reconstituted at pH 7.0 and foams prepared by air bubbling. An original approach was followed to study the foam stability against drainage, involving monitoring of the liquid fraction as a function of both height in the foam column and time, and analysing the whole set of time and height liquid fraction profiles using multivariate statistics. The effects of dry-heating parameters were markedly interdependent, resulting in complex effects on foam stability. However, the results suggest that dry-heating at pH 3.5 increased foam stability. Moreover, the a w adjustment step, though consisting in a two-week pre-conditioning at room temperature, also had a significant effect on the foam stability, of the same order of magnitude as dry-heating effects. Highlights • We monitored drainage using time and height liquid fraction profiles. • Multivariate statistics allow comparison of foam stabilities. • Storage of powders prominently impacted foam stability. • Powder dry-heating parameters caused complex effects on foam stability. [ABSTRACT FROM AUTHOR]

Abstract Block freeze concentration (BFC) is a promising technique to concentrate coffee extract in the freeze-dried coffee industry. The application of thermal treatments (the use of different cooling/heating ramps and isothermal stages) to BFC lab-scale operations has increased the process's efficiency but has simultaneously led to the formation of gels that reduce the recovery of solids. In this work, we present a methodology to monitor the rheological behavior of coffee extract when subjected to temperature profiles similar to those presented during lab-scale BFC processes. It was revealed that cryogelation occurs at the early stages of the isothermal step (annealing) of a multi-stage temperature profile. For gelation to occur, the annealing temperature should be close to the water's equilibrium melting temperature. Phenomena leading to more efficient BFC processes (solids elution and water recrystallization during isothermal thawing) also promote cryogelation. Highlights • Gelled fractions appear as a consequence of cryogelation during the isothermal stage. • Solids elution and water recrystallization during isothermal thawing lead to gelation. • Annealing temperatures close to T o are required for gelation problems to take place. • Rheology can be used to predict if BFC processes will undergo gelation problems. [ABSTRACT FROM AUTHOR]

Owing to the growing demand for ready-to-eat food and the expanding food-processing sector, consumption of freeze-dried fruit food is increasing globally, holding significant market value. Texture is critical in determining the overall quality and consumer acceptance of freeze-dried fruit products. However, texture formation and control remain one of the least well-described quality attributes due to challenges from complex fruit matrices and testing methodologies, impeding advancements within the freeze-drying industry. Focusing on the two main types of freeze-dried fruit products (i.e. , freeze-dried intact and restructured fruits), this review elaborates on the formation mechanisms and control technologies of the texture properties, primarily analyzing from the perspective of carbohydrates in fruits. Try to establish a porous scaffold model to clarify the dominant attributes of texture formation during freeze-drying, thereafter explain and compare the formation and control principles governing the texture of these two types of freeze-dried fruits. The porous scaffold of freeze-dried fruit is built by a polysaccharide network and small molecule sugars within glassy amorphous at sufficiently low water content, showing various macroscopic porous characterization. Three dominant attributes of texture formation are summarized, namely pore/cellular morphology, solids, and water content in the final freeze-dried fruit matrix. Most texture control techniques are based on the modification of these three dominant attributes. Furthermore, freeze-dried restructured fruits exhibit a greater texture enhancement potential than intact fruits due to the loss of cellular structure, providing new inspiration for the future development of personalized multi-functional freeze-dried snacks. • A porous scaffold model to summarize texture formation is established. • Pore morphology, solids, and water content determine freeze-dried fruit texture. • The cellular structure primarily accounts for the texture variation between two freeze-dried fruit types. • Most texture control methods modify pore morphology, solids, and water content. • Restructured freeze-dried fruits show greater texture enhancement potential. [ABSTRACT FROM AUTHOR]

Abstract Processed samples (air-dried @ 40 and @ 60 °C and freeze-dried) of sea fennel (Crithmum maritimum L.), an autochthonous spice with interesting market potential, were analyzed by headspace gas-chromatography/mass spectrometry and classification capabilities of an electronic nose in discriminating between samples with stepwise forward statistics were evaluated as well. Freeze-drying process was the most preservative in terms of limiting darkening without compromising appearance of the final product, providing weight loss of about 85% and water activity below the limit for mold growth issues. Headspace analysis of samples highlighted the presence of 35 volatiles grouped as terpene hydrocarbons, oxygenated terpenes, sesquiterpen hydrocarbons, phenyl propanoids, not-terpenic aldehydes and not-terpenic ketones. Correlations emerged between selected sensors and some detected volatile organic compounds. Stepwise linear discriminant analysis and simple K-nearest neighbors obtained a 100% overall correct classification rate in cross-validation of the electronic nose in classifying samples, whereas stepwise quadratic discriminant analysis and Naive-Bayes gave 93.3%. The sea fennel could be a new interesting spice to launch in the food market and the electronic nose showed the potential to be used in monitoring the industrial process aimed at extending its shelf-life. Graphical abstract Unlabelled Image Highlights • Air-dried and freeze-dried sea fennel (Crithmum maritimum L.) samples were prepared • VOCs emitted by samples were chemically characterized • Classification capability of an electronic nose among samples was tested • Correlations emerged between sensor responses and detected VOCs • Supervised methods of classification with reduction techniques were used [ABSTRACT FROM AUTHOR]

(1) Background: Drying is an important process in the research of bioactive compounds. The aim of this study was to identify an optimal condition to dry carrot peel. (2) Methods: In this study, various drying conditions including hot-air (50 °C and 100 °C), vacuum (50 °C and 100 °C), microwave (600Wand 1200 W) and freeze dying (-45°C), were applied, and the phytochemical yield and antioxidant activity of carrot peel were then assessed. (3) Results: The results showed that the highest amount of phytochemical compounds was achieved by microwave drying at 1200W, followed by microwave drying at 600Wand freeze drying at -45°C. In contrast, hot-air drying resulted in the lowest level of phytochemical compounds. Regarding the antioxidant activity of carrot peel, microwave drying at 1200Wwas an optimal condition as it possessed the best antioxidant activity whereas hot-air, vacuum and freeze drying were not effective methods for retaining antioxidant activity. (4) Conclusions: Based on the results obtained from this study, microwave drying at 1200 W is recommended to dry carrot peel for potential application in the nutraceutical, beverage and/or functional food industries. [ABSTRACT FROM AUTHOR]

The overall permeation rate through asymmetric oxygen transport membranes is significantly governed by the porous support. Therefore, the microstructuring of the support's pore structure is essential to achieving the highest performances. Freeze casting is already proven to obtain hierarchical porous structures with low tortuosity, which potentially enhances the oxygen flux of oxygen transport membranes. Although a performance improvement has been reported, such improvement is not self-evident. There has yet to be a detailed comparison of the achieved microstructures in order to identify the relevant microstructural parameters. Asymmetric membranes from Ba 0.5 Sr 0.5 (Co 0.8 Fe 0.2 ) 0.97 Zr 0.03 O 3-δ consisting of a surface-activated 20 µm membrane layer with tape- or freeze-cast supports that have identical pore volume and layer thickness were manufactured, characterized, and compared by means of oxygen flux measurements. They were also microstructurally investigated via computed X-Ray tomography and flow simulation experiments. In the air/Ar gradient, the freeze-cast support membrane performs below the tape-cast-supported membrane. In particular, the transition zone close to the membrane, which is caused by the freezing process, significantly constrains the diffusivity and permeability of the support, and therefore leads to concentration polarizations. At temperatures below 800 °C, surface exchange kinetics at the membrane-support interface become rate-limiting. [ABSTRACT FROM AUTHOR]

Carrot leaves, which are generally considered as agricultural residue, are rich in bioactive compounds, such as polyphenols. This study investigates the extraction of polyphenols and luteolin (flavonoid) from freeze-dried and ground carrot leaves (d < 100 μm) using subcritical water (SCW). Water at elevated temperatures and at high pressure (40 bar) could behave as low-polar solvent to enhance extraction of organic compounds. SCW was investigated at different temperatures (110-230 °C), time (0-114 min), and solid-liquid ratio (15 and 35 g/L). Accordingly, it was revealed that total phenolic content (TPC) from carrot leaves using SCW has an increasing trend with temperature and resulted in 42.83 ± 1.85 mg per g of dry weight in gallic acid equivalent at 210 °C/113.5 min. However, luteolin content using SCW extraction behaved differently, where increase of temperature adversely affected its content. Hot water extraction studies revealed the presence of optimum luteolin content (0.768 ± 0.009-mg/g dry weight) at 120 °C for 10 min. In conclusion, it was shown that carrot leaves are a promising feedstock to extract polyphenols that has high content of luteolin. [ABSTRACT FROM AUTHOR]

The main objective of the present study was to investigate the effect of spray and freeze-drying techniques on the microencapsulation of a gallic acid compound using the acid-hydrolyzed low dextrose equivalent potato starch as a wall material. During the experiment, it was possible to achieve encapsulation effi ciency of 70-84% for the freeze-dried and 65-79% for spray-dried samples, without statistically signifi cant difference (P>0.05) in the encapsulation effi ciency between the mentioned methods. Spray-dried samples formed spherical capsules with a higher number of micropores. Meanwhile, freeze-dried samples were shapeless, exposed larger pore volume (from 2.4x10-3 to 9.5x10-3 cm3 /g against 1.2×10-3 4.9x10-3 cm3 /g; analyzed by Barrett-Joyner-Halenda method) and overall higher surface area (0.632-1.225 m2/g against 0.472-1.296 m2/g; analyzed by Barrett-Joyner- -Halenda method). Due to this fact, more gallic acid molecules were exposed to environmental factors and can be counted as losses. In addition, freeze-dried samples demonstrated lower water activity than spray-dried samples (0.075±0.014 against 0.178±0.008). Results showed that it is not practical to use freeze-drying for modelling encapsulation for food industry without a special necessity for protection of easily degradable chemical compounds. The present work makes a basis for the future studies of the microencapsulated phenolics application in food production. [ABSTRACT FROM AUTHOR]

The paper discusses the infl uence of the addition of freeze-dried tomatoes on the chemical composition and selected physical properties of extruded corn snacks. Corn grits were replaced with dried tomatoes in the amount from 5 to 30% of corn mass. The total lycopene and phenolic content, the scavenging ability and the ferric reducing antioxidant power were determined along with the content of neochlorogenic, chlorogenic, p-coumaric acids and rutin. Also evaluated were selected physical properties, colour and the sensory profi le of corn snacks enriched with tomatoes. A greater tomato addition increased the volume of bioactive compounds, especially the total phenolic content. Snacks enriched with tomato exhibited a lower expansion ratio, water absorption and solubility indices, lightness and sensory characteristics but higher density, hardness and redness than corn snacks. Powdered tomato seems to be a functional additive with the high content of biologically-active compounds and the enriched snacks displayed good physical properties if the tomato level did not exceed 20%. A higher amount of the additive signifi cantly lowered the expansion as well as increased the hardness of snacks. Still, the corn products with 25 and 30% of powdered tomato were more valuable due to their much higher level of bioactive components compared with the regular corn snacks. [ABSTRACT FROM AUTHOR]

Maintaining low moisture content is seen as crucial to sustaining long term stability in freeze dried (FD) cakes as higher moisture could lead to cake collapse, degradation and a loss of biological potency. Using a combination of gravimetric data and video images captured from a Dynamic Vapour Sorption instrument the onset humidity Collapse Point (RH cp ), the humidity onset Crystallisation (RH c ) and onset Glass Transition (RH g ) points for a series of freeze dried cakes at 10, 25 and 40 °C have been determined. The moisture sorption behavior with respect to cake collapse and other morphological phase transitions are reported for a two freeze drying excipients and one product formulation; sucrose, trehalose (both 5% w/w) and an influenza antigen (A/Wisconsin/15/2009 H3N2 NYMCX-183, formulated with 1.1% w/w sucrose). Stability maps for all three formulations tested were reported as a function of %RH and temperature using the methods described in this work, thus the direct visualization of collapse behavior for any FD cake can now be standardized and routinely determined, facilitating the formulation of FD products with improved stability and storage performance. [ABSTRACT FROM AUTHOR]

This study aimed to use the Instant Controlled Pressure Drop as a texturing pretreatment prior to air flow drying as a new way for the manufacturing of egg white and yolk powders evaluating the impact of DIC operating parameters; the saturated steam pressure and processing time, on the physical and functional properties of the end products. The obtained results showed that the DIC-textured egg white and yolk powders had high quality attributes compared to those obtained from classical air flow drying. Moreover, it was better than freeze dried powders in terms of water absorption capacity, emulsifying capacity, and foaming capacity and stability. [ABSTRACT FROM AUTHOR]

M. floribunda fruit was studied to characterize its chemical composition. The chemical composition, bioactive compounds, antioxidant activity and volatiles of the fruit were determined. The chemical composition was determined according to AOAC and AOCS, the bioactive compounds by HPLC, the volatiles by GCMS and the antioxidant activity by ABTS + and DPPH methods. The chemical composition of the freeze-dried fruit was 1.89 g·100 g −1 , 2.43 g·100 g −1 , 4.78 g·100 g −1 and 90.89 g·100 g −1 of ashes, lipids, proteins and total carbohydrates on a dry base, respectively. The concentration of the carotenoids was 52.22 mg·100 g −1 and for the flavonoid rutin was 78.56 mg·100 g −1 . The gallic and ellagic acid contents were 5.45 mg·g −1 and 2.21 mg·g −1 , respectively. The cis -β-ocimene corresponded to 50.90% of the volatiles. The antioxidant activity by ABTS + method was 550.14 µmol Trolox·g −1 and by the DPPH method the EC 50 was 85.68 g·g −1 . The fruits presented relevant antioxidant activity, a high concentration of carotenoids and of rutin. [ABSTRACT FROM AUTHOR]

The effect of sprouting on rheological, functional, thermal and micro structural properties of freeze dried onion powders obtained from four Indian onion cultivars (Punjab White, Punjab Naroya, PRO-6 and Commercial) were studied to assess the feasibility of using sprouting as a tool to imparting desirable thermal, functional and rheological properties in various food products. Sprouting showed an increase in protein, ash and fibre content with decrease in fat and carbohydrate content of onion powders. Functional properties (water solubility index, hygoscopicity, dispersibility and wettability) improved in sprouted powders as compared to the unsprouted powders. Sprouted onion powders showed lower elastic modulus (G′) and viscous modulus (G") in the linear viscoelastic region as compared to unsprouted powders. Sprouted powders recorded significantly (P < 0.05) higher glass transition temperature than the unsprouted powders. The morphological pattern which differed in both types of powders was determined by scanning electron microscopy. The increased protein content accounted for increase in particle size and solubility index thereby decreasing the viscosity as reflected by lower elastic (G′) modulus in sprouted onion powders. The improvements in composition and quality parameters were seen in all the cultivars tested showing that sprouting could be beneficial for product development across cultivars. [ABSTRACT FROM AUTHOR]

Sourdough, a mixture of wheat flour and water, fermented by the action of lactic acid bacteria (LAB) and yeasts, presents some technological advantages, such as improvement in dough structure, flavor, aroma, bread texture, and shelf life. Few studies related to methods of preservation of sourdoughs are currently available. This work aimed to test the cryoprotective effect of trehalose on microorganism survival and its effect on freezing, freeze-drying and storage of freeze-dried sourdough, and to molecularly identify predominant bacteria and yeasts. Refined and whole wheat flour were used to prepare the sourdough. On the 14th day of production, varying amounts of trehalose were added (0, 10 and 15%) and the sourdough was freeze-dried. The cryoprotective effect of trehalose was evaluated before and after freezing, after freeze-drying, and after 15, 30 and 45 days of storage. Predominant microorganisms were molecularly identified through amplification and sequencing of rDNA fragments. Addition of trehalose promoted a cryoprotective effect survival of microorganisms, and it was more significant for LAB. Lactobacillus plantarum, Lactobacillus fermentum, Saccharomyces cerevisiae, Pichia anomala and Pediococcus pentosaceus, were the main species recovered. [ABSTRACT FROM AUTHOR]

This study aimed to examine the effects of porous structure and water plasticization on the mechanical glass transition temperature ( T g ) of freeze-dried trehalose solid and cookie. The thermal T g and mechanical T g were evaluated by differential scanning calorimetry (DSC) and thermal rheological analysis (TRA), respectively. The mechanical T g of the porous trehalose sample was slightly higher than that of the pellet sample. The mechanical T g s for pellet and porous trehalose samples were higher than thermal T g . Although pellet, crust, and crumb cookie samples showed indistinct glass transition behavior in the DSC thermosgrams, TRA revealed a clear glass transition. There were little differences in the mechanical T g of the cookie samples. The mechanical T g decreased with an increase in water content, and mechanically and thermally critical water contents (water content at T g = 25 °C) were evaluated. Fracture properties of the cookie sample changed discontinuously at the thermally critical water content. [ABSTRACT FROM AUTHOR]

This study determined nutrients, chemical contaminants, (insecticide residues and heavy metals), and natural toxic substances (nitrate, nitrite, cyanide, oxalate, phytate, and trypsin inhibitor) in tubers of Jerusalem artichokes—Kaentawan in the Thai language—grown in four major provinces in Thailand. They were purchased, prepared, homogenized, and freeze-dried for further analysis using standard methods. All Kaentawan samples contained considerable amounts of fructans and dietary fiber (15.4±0.2 g and 3.2±0.8 g/100 g fresh weight [FW], respectively), as well as potassium and iron (339±61 and 0.32±0.05 mg/100 g FW, respectively). All samples had very low amounts of insecticide residues (37 compounds), cyanide, and trypsin inhibitor, as well as Pb, Cd, nitrate, and nitrite (0.82±0.09, 0.10±0.02, 1.9–17.5, and 0.01–0.24 mg kg −1 FW, respectively), in addition to oxalate and phytate (14±9 and 0.17±0.02 mg/100 g FW, respectively). This study’s data can be used for food composition databases and for safety consumption. [ABSTRACT FROM AUTHOR]

Physicochemical and functional properties of freeze-dried egg powders (egg white, egg yolk, and whole egg) from Japanese quail and white Leghorn chicken were studied comparatively. All egg powders had protein content in the range of 91.13-97.03 g/100 g powder. The quail egg powder had higher mineral and essential amino acid contents, but lower fat content as compared to chicken egg powders (P < 0.05). Moreover, egg white powder from both quail and chicken presented higher total amino acids content than corresponding whole egg and egg yolk powders, respectively. Fourier transform infrared spectroscopic study revealed that β-sheet is the major secondary structure of all egg powders. Based on differential scanning calorimetry analysis, quail egg powders showed slightly lower denaturation temperatures than corresponding chicken egg powders (P < 0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis study showed the slight difference in protein patterns of corresponding quail and chicken egg powders. The quail egg powders presented higher protein solubility than corresponding chicken egg powders at all pH tested. Furthermore, quail egg powders exhibited higher emulsion activity index and emulsion stability index with higher foam expansion and stability than the corresponding chicken egg powders. Therefore, Japanese quail egg powders could be used as an alternative to white Leghorn chicken egg in the preparation of foods and diets that require high protein content with positive health benefits. [ABSTRACT FROM AUTHOR]

A cost effective and environmentally safe analytical method for rapid assessment of total phenolic content (TPC) in freeze dried lemon juice samples was developed using transmission Fourier-transform infrared spectroscopy (FT-IR) in conjunction with chemometric techniques. Two types of calibrations i.e. simple Beer's law and partial least square (PLS) were applied to investigate most accurate calibration model based on region from1420 to 1330 cm-1. The better analytical performance was obtained by PLS technique coefficient of determination (R²), root mean square error of calibration (RMSEC) with the value of 0.999 and 0.00864, respectively. The results of TPC in freeze dried lemon juice samples obtained by transmission FT-IR were compared with TPC observed by Folin-Ciocalteu (FC) assay and found to be comparable. Outcomes of the present study indicate that transmission FT-IR spectroscopic approach could be used as an alternative approach in place of Folin-Ciocalteu (FC) assay which is expensive and time-consuming conventional chemical methods for determination of the total phenolic content of lemon fruits. [ABSTRACT FROM AUTHOR]