Stability evaluation of quail egg powder obtained by freeze-drying

This study aimed to produce quail egg powder by freeze-drying and to evaluate its stability in different types of flexible packages (low-density polyethylene, polypropylene and pigmented polypropylene) in high relative humidity (approximately 81%) at 25 °C during 59 days. The packages were evaluated for water vapor permeability and freeze-dried egg was characterized as to bulk density and hygroscopicity (initial time), and moisture, water activity, pH and color (until the end of storage). GAB, BET and Peleg sorption isotherm models were adjusted to the experimental data to predict monolayer moisture content in the powdered eggs. The freeze-dried quail eggs presented a little oscillation in color coordinates, reduction in pH, and increase in moisture content and water activity during storage for all packages used. No evaluated packaging was sufficiently effective as a moisture barrier. GAB and BET models fitted better to the experimental data for the freeze-dried quail egg, and the estimated monolayer moisture values were 0.0333 and 0.0227 g H2O/g solids, respectively. The powdered quail egg has industrial potential, however, it is susceptible to significant changes throughout storage when exposed to high relative humidity and conditioned in the tested packages. Commercially, as this product can be sold in regions with different temperatures and relative humidity, it is essential to consider the use of preservatives or anti-wetting agents.

The Study of Sorption Characteristics of Dried Crab Stick Product Using Dynamic Vapor Sorption

The research delved into the sorption characteristics of dried crab stick products using dynamic vapor sorption (DVS). The obtained sorption isotherm data, including equilibrium moisture content (Me) and water activity (aw), were fitted with 6 different sorption isotherm models, such as Brunauer-Emmett-Teller (BET), Guggenheim-Anderson-Boer (GAB), Pickett-Modified BET, Adam and Shove, Blahovec-Yanniotis, and Peleg. The results showed that the Peleg model was the best-describing model with a coefficient of determination (R2), chi-square (χ2), root mean square error (RMSE), and standard error of estimate (SEE) ranging from 0.988 to 0.998, 0.719 to 4.349, 0.431 to 2.609 and 0.692 to 1.703, respectively. According to the classification of the shape of moisture sorption isotherm, the isotherm type III and II were found in this research for adsorption and desorption, respectively. The GAB and BET models were used to estimate monolayer moisture content (M0) of the sample and it was found that the M0 ranged from 3.65 to 5.36 % dry basis and 4.57 to 4.83 % dry basis for GAB and BET models, respectively. Blahovec-Yanniotis’s model was applied in this work to investigate the contribution of water and the result showed that the contribution of solution water played a major in the moisture changes of the sample during the adsorption and desorption process. Moreover, sorption isotherm data were modeled with 0 and 1st order reaction kinetics, and the results demonstrated that 0 order and 1st order models were the most appropriate model to describe moisture changes behavior of the sample at each relative humidity step for adsorption and desorption, respectively. HIGHLIGHTS The construction of sorption isotherms of dried crab stick product using dynamic vapor sorption GAB and BET models were used to estimate monolayer moisture content Peleg model was the most appropriate model to describe sorption behaviors of dried crab stick product Blahovec-Yanniotis provided the contribution of water information of dried crab stick during adsorption and desorption processes The application of reaction order kinetics could provide the information of moisture changing behaviors at each relative humidity step for adsorption and desorption processes GRAPHICAL ABSTRACT

Moisture Sorption Characteristics as Influenced by Application of Hurdles in Dambu-nama Production

Moisture transfer characteristics of dambu-nama (DN) as influenced by addition of citric acid, salt and sugar as hurdles were investigated. Four products comprising DN with 0.1% citric acid + 2% salt and 2% sugar (DNC0.1); DN+ 0.2% citric + 2% salt + 2% sugar (DNC0.2); DN + 0.3% citric acid +2% salt + 2% sugar (DNC0.3) and a control DN without citric acid , salt or sugar (DNC0) were produced and subjected to moisture sorption studies at different temperatures (30, 40, 50 and 60oC) and relative humidities of(10-96%). Incorporation of the hurdles into dambu-nama resulted in increase in monolayer moisture contents, surface areas, net isoteric heats and entropy of sorption. The isotherms obtained were best described by the Henderson model followed by the GAB and Oswin models. The hurdles also resulted to a J-shaped isotherm instead of the sigmoidal isotherm shape.

Evaluation of water sorption isotherm, glass transistion temperature, vitamin C and color stability of mango peel powder during storage

The purpose of this work was to study the physical and chemical stability of the mango peel powder produced by hot-air drying. Sorption isotherms at 25 °C and glass transition temperatures (Tg) of the samples in equilibrium at different aw were determined. The degradation of vitamin C and color parameter b* was evaluated along storage under controlled conditions (relative humidity = 60%, temperature = 10, 25 and 35 °C) during 180 days. GAB model well-described water adsorption of the product, showing a monolayer moisture content (Xm) of 0.1260 g water/g dry solids and a critical aw of 0.56. The Gordon-Taylor model predicted the plasticizing effect of water on glass transition temperature, since Tg of the powders kept at different relative humidity conditions decreased as water activity increased. No visual signs of agglomeration and darkening were observed for samples stored at aw ≤ 0.529. The powders are a source of calcium and rich in potassium, copper, magnesium and manganese. The concentration of inorganic contaminants and pesticide residues were below the maximum allowed limits. The degradation of vitamin C and color parameter b* followed the first and zero-order kinetic models, respectively. The study indicated good stability for the powders along the storage at 10 and 25 °C, which can be incorporated into different food products, showing high retention of vitamin C, phenolic compounds, antioxidant activity and maintenance of color characteristics.

Desorption capacity of raw energy bars with fruits of Zizyphus jujuba Mill. - Bulgaria

The current study presents a mixture for raw energy bars of fresh fruits of the exotic fruit Zizyphus jujuba Mill. with origin - Bulgaria. The physico-chemical indices of the ready mixture are analyzed. A high content of carbohydrates - 24.45% and of nourishing fiber - 22.08% is reported. The desorption capacity of the exotic mixture is examined for temperatures of 10°С, 25° and 40°С in eight watery activities from 11% to 85%. The analysis shows that the equilibrium moisture lowers with the raise of temperature in constant watery activities. The desorption isotherms are of type III according to the classification of Brunauer et al. The modified model of Halsey is recommended for the isotherms description according to the estimation criteria distribution, and the model of Oswin - as a second modified model. The values of the monolayer moisture content in aw <0.5 for temperatures 10°С - 5.46% dry basis (d.b.), 25°С - 5.72% d.b. and 40°C - 4.05% d.b. are calculated Brunauer-Emett-Teller model.

Stability of jabuticaba flakes obtained by drum drying with cassava starch as additive

The stability of jabuticaba flakes produced by drum drying using cassava starch as additive was evaluated. Sorption isotherms at 25 ºC were determined. Samples were stored under controlled conditions (relative humidity = 60%, temperature = 20, 25 and 35 ºC) for until 235 days. The anthocyanin content and color parameters (L*, a* and b*) were monitored. GAB model led to the best adjustment of sorption isotherm, with a monolayer moisture value of 0.1596 g water/g dry basis. The visual observations did not point out agglomerations and darkening at aw values higher than 0.33 at 25 ºC, which can be considered the critical point. The degradation of anthocyanin and color parameters followed first and zero-order kinetic model, respectively. The half-life times (630 to 1450 days) showed good stability at 25 ºC, while the temperature acceleration coefficient (2.2 ≤ Q10 ≤ 3.2) and activation energy (15 ≤ Ea ≤ 19 kcal/mol) values demonstrated a high-temperature sensitivity.

Sorption characteristics of ready-made mixtures containing oatflakes, apples, and cinnamon

The present paper studies the sorption characteristics of readymade mixtures containing oatflakes – 89.5%, apples – 10%, and cinnamon – 0.5 % at the temperatures of 10°C, 25°C and 40°C and for eight water activities in the 11% - 85% range. The results obtained demonstrate that at a constant water activity, the increase in temperature is coupled with a decrease in equilibrium moisture content. The sorption isotherms of the analyzed ready-made mixture belong to Type III according to the classification of Brunauer et аl. In order to describe the isotherms following the evaluation criteria, that is mean relative error, standard deviation, and distribution of residuals, the study recommends the threeparameter modified Oswin for adsorption and the Henderson model for desorption. Via linearization of the Brunauer-Emmett-Teller model, we calculate the values of monolayer moisture content (MMC) at aw < 0.5 for both processes. For adsorption, the ММC falls within the 2.51% - 3.57% d.b. range, whereas for desorption it is within the 3.41% - 3.71% d.b. range. Temperature affects the MMC since its increase leads to a decrease in the ММC for both processes. For adsorption, at a temperature between 10°C and 40°C the ММC decreases by 1.06%, and for desorption - by 0.3%.

Experimental Investigation of Moisture Sorption Isotherms for Mefenamic Acid Tablets

The moisture sorption isotherms of Mefenamic acid tablets were investigated by measuring the experimental equilibrium moisture content (EMC) using the static method of saturated salt solutions at three temperatures (25, 35, and 45°C) and water activity range from 0.056 to 0.8434. The results showed that EMC increased when relative humidity increased and the sorption capacity decreased, the tablets became less hygroscopic and more stable when the temperature increased at constant water activity. The sorption curves had a sigmoid shape, type II according to Brunauer’s classification. The hysteresis effect was significant along with the whole sorption process. The results were fitted to three models: Oswin, Smith, and Guggenhein - Anderson and de Boer. According to the fitting results, the GAB model was the most appropriate model to describe the sorption behavior of Mefenamic acid; it had a regression coefficient range (0.9803-0.994), %E (0.69-4.06), and low values of SEE (0.85-2.2). The monolayer moisture content was calculated using the GAB model and it was concluded that the tablets should be stored at moisture content equal or slightly higher than (0.2046, 0.1843, and 0.1437 %) for desorption and (0.2073, 0.1269, and 0.1452 %) for adsorption for the three temperatures.

Moisture Sorption Studies of Kamsa:

The study was aimed at establishing storage stability indices of a traditional smoke dried product kamsa, produced from beef. The sample was produced using a standardized method and stored over a period of six months. Data for sorption studies was generated between the temperature ranges of 33.8oC to 50oC for adsorption and desorption using the gravimetric method. The data was analyzed using the Guggeinheim Anderson de Boer (GAB) and the Brunaeur Emmett Teller (BET) model equations. A nonlinear regression analysis method was used to evaluate the constants of the sorption equations. From the results using the GAB model, the monolayer moisture content (Mo) decreased from 0.021 to 0.008gH2O/g solids; the value of the constant K, increased from 0.587 to 1.052; and the value of CG decreased from 2.481 to 2.154. For desorption, the value of Mo decreased from 0.021 to 0.004g H2O/g solids; K increased from 0.587 to 1.035; CG increased from 2.173 to 2.646. The model gave low percent standard error values. The correlation coefficient (R) values obtained for both adsorption and desorption ranged from 0.998 to 0.999, and 0.991 to 1.000, respectively. The Mo values using the BET model at 33.8oC for both adsorption and desorption were 0.055, 0.055, 0.052, 0.049, 0.058, 0.055g H2O/g solid; and 0.057, 0.057, 0.052, 0049, 0.052, 0.057g H2O/g solid, respectively. At 50oC, the adsorption and desorption monolayer moisture values were 0.039, 0.047, 0.049, 0.049, 0.052, 0.058 gH2O/g solids; and 0.054, 0.047, 0.052, 0.052, 0.039, 0.052 gH2O/g solids, respectively. The study concluded that, the GAB model was more suitable in describing the sorption characteristics of Kamsa within the prescribed water activity and temperature ranges.

Acacia Gum as a Natural Anti-Plasticizer for the Production of Date Syrup Powder: Sorption Isotherms, Physicochemical Properties, and Data Modeling

The thermoplastic and hygroscopic behaviors of date syrup (DS) challenge the DS drying process. In this context, DS was mixed with 30%, 40%, 50%, and 60% acacia gum (AG) and subjected to a drum dryer. The chemical composition, bulk density (pb), caking degree (CD), glass transition temperature (Tg), and color values of DS powders were studied. The sorption isotherms were also obtained and compared to that of those predicted by mathematical models. According to the results, increasing the AG concentration enhanced the moisture content, pb, brightness, and Tg while it reduced the CD and equilibrium moisture sorption. All DS powders had type III isotherm behavior, i.e., similar to high-sugar foods. Guggenheim-Anderson-de Boer (GAB) and Peleg models were found to be suitable for fitting the experimental data and these models explained the monolayer moisture content decrease with increasing AG concentration. These results of the present study, for the first time, verified that the AG can be used as a natural anti-plasticizer agent for DS powder production.