Increase In Drying Temperature Research Articles

Effects of delayed drying interval and the drying temperature of popcorn on sensory and technological quality

The maintenance of the sensory and expansion properties of popcorn are essential during the post-harvest stages. The delay in drying, and drying temperature can negatively influence the technological and sensorial quality of the popcorn. Therefore, in this study the effects of the delayed drying interval and drying temperature on black and white popcorn were evaluated. The increase in delayed drying interval, linked to increased drying temperature provided a reduction in protein solubility (31.14 and 21.06%), expansion weight (65.01 and 100.00%) and expansion yield (89.40 and 100.00%), when analyzing the white and black popcorn, respectively. Furthermore, an increase was observed in expansion residue (308.07%) and a reduction in the brightness of the expanded popcorn (24.77%), when analyzing the white popcorn. It was observed a reduction in all evaluated sensory parameters (Global acceptance, purchase intent, and expanded popcorn size, odor and flavor). In both genotypes studied, the maintenance of sensory and expansion properties, which give the higher added value to this product, were achieved with the lower delayed drying interval and drying at 40°C. The outcomes of this study showed the importance of drying popcorn grains right after harvesting. The effects of drying delay significantly affected the quality of both studied genotypes.

Study of the drying kinetics of black mulberry (Morus nigra L.) leaves

Black mulberry leaves have been used to promote health and prevent diseases due to their biological properties. Drying leaves allows greater stability during storage and marketing. However, studying this operation is important to ensure that the properties are maintained. Therefore, the objective of this study was to use mathematical modeling to define the model that best fits to the experimental data of the drying kinetics at temperatures of 40, 50, 60, and 70°C. Liquid diffusion, leaf surface area, the relationship between temperature increase and diffusion coefficient, and energy activation were also determined. Among the mathematical models studied, the Page model was the one that best described the drying process of black mulberry leaves. As for the diffusion coefficient, the values increase as the drying temperature increases. The activation energy was 65.418 kJ mol-1, and it was observed that the lower the activation energy, the greater the water diffusivity in the product. The drying kinetics data of black mulberry leaves allowed a better understanding of this operation in a matrix with wide application potential. Drying black mulberry leaves at different temperatures altered their color. Considering the evaluations, temperatures of 40 and 50°C are the most indicated for drying black mulberry leaves.

Effect of drying temperatures and using prebiotics on the physicochemical and microbiological properties as well as consumer acceptance of probiotic-enriched Lor cheese snacks produced by vacuum drying

This study assessed the impact of drying temperatures (37 °C, 45 °C, and 55 °C) and using prebiotics (inulin or maltodextrin) on the physicochemical and microbiological properties as well as consumer acceptance of probiotic-enriched Lor cheese snacks produced by vacuum drying. The Lor cheese snacks produced using Lactobacillus acidophilus DSM 20079 as probiotic bacteria were stored at 25 °C for 60 days. The moisture content as well as aw and titratable acidity values of the Lor cheese snack produced by vacuum drying at 37 °C were higher than those produced by vacuum drying at both 45 °C and 55 °C. The highest fracture force values were determined in the Lor cheese snacks produced using maltodextrin and by vacuum drying at 55 °C. The L* and a* values decreased and the b* values of the Lor cheese snacks increased with the increasing drying temperature, while the type of prebiotic used did not significantly affect the L*, a*, and b* values. The taste, aroma, texture, and overall acceptability scores in the Lor cheese snack samples produced by vacuum drying at 45 °C and 55 °C were found to be similar. The counts of L. acidophilus were above 8.0 and 6.0 log cfu/g in the Lor cheese snacks produced by vacuum drying at drying temperatures of 37 °C and 45 °C, respectively, after 60 days of storage. In conclusion, the present study suggests that the use of maltodextrin and vacuum drying at 45 °C are suitable to produce the Lor cheese snacks considering their physicochemical and microbiological properties as well as consumer acceptance.

Changes in mango foam morphology and its effects on texture and selected phenolics during foam mat drying

Foam mat drying can yield various foam morphologies, influencing product quality and texture. This study investigated the effects of foam density (0.3, 0.5 and 0.8 g/cm3), drying temperature (60, 70 and 80 °C) and final moisture content (12 and 4% d.b.) on drying characteristics and product quality. Lowering foam density increased porosity, enhancing the second falling drying rate and minimizing differences in drying time to achieve moisture contents of 12 and 4% (d.b.). Lower-density mango foams exhibited superior retention of total phenolics content (TPC) and antioxidant activity compared to higher-density foams. TPC losses and reduced antioxidant activities were not significantly different for 12% and 4% (d.b.) mango foams. However, a shorter drying time with increased drying temperature resulted in higher TPC losses and reduced antioxidant activities, while maintaining higher levels of gallic acid and chlorogenic acid. The drying temperature had no discernible impact on shrinkage and texture. Lower-density foam structures exhibited reduced hardness, crispness and toughness. Mango foam mats with an initial density of 0.3 g/cm3, dried at 60 °C, showed minimal shrinkage (1–2%), TPC loss (7%), and reduced antioxidant activity (11–17%). However, panelists preferred a commercial snack due to the sponginess and less crispiness of 4% dried mango foam mats with initial densities of 0.3 and 0.5 g/cm3. Compared to commercial mango leather, the 12% dried mango foam mat with an initial density of 0.8 g/cm3 had similar toughness, but was harder, resulting in a preference for commercial mango leather.

Effects of pretreatment and drying temperatures on physicochemical and antioxidant properties of dried duku (Lansium domesticum)

Duku (Lansium domesticum) is a native of Southeast Asia. Duku is a seasonal fruit and highly deteriorated due to high moisture content of more than 80 %, thus difficult to commercialise due to the short shelf life. The transformation of fresh into dried fruit will increase the commercial values as well as be a solution to reduce fruit loss. This study was conducted to evaluate the effects of pretreatments and drying temperatures on physicochemical and antioxidant properties in dried duku fruit. The duku fruits (whole, flesh, peels and seeds) were subjected to pretreatment process with ascorbic acid solution, sodium metabisulfite solution, sodium erythorbate solution and blanching. Then, the samples were dried at 50 °C, 60 °C, 70 °C and 80 °C, respectively. Determination of total phenolic content (TPC) was carried out based on the Folin-Ciocalteau method. The antioxidant activities were evaluated using ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl). The pH values of all parts of duku were decreased as the drying temperature increases. Seed (pretreated with sodium metabisulfite, dried at 80 °C) showed the highest total phenolic content value with 116.84 ± 0.31 mg gallic acid equivalents per g fruit extract (GAE/g), while lowest in flesh (pretreated with ascorbic acid, dried at 50 °C). Seed (pretreated with sodium metabisulfite, dried at 50 °C) has the highest antioxidant capacity with IC50 value of 41.15 µg/ml (ABTS free radical scavenging) and 121.35 µg/ml (DPPH free radical scavenging) compared to other fruit parts, pretreatments and drying temperatures. The findings of this study indicate the potential of all parts of duku fruit as a valuable source of nutrients. Information on the nutritional and antioxidant properties of this Malaysia's seasonal fruit reveals its potential to be commercialized into different food and beverage products.

Changes in Moisture Desorption Rate of Shelled Corn Layers in a Low-Temperature Deep-Bed Drying Column

To optimize grain drying processes, high-moisture shelled corn was dried in a device using a combination of three temperatures (45, 55 and 65 °C) and hot-air velocities (0.7, 1.1 and 1.3 m·s-1). The grain moisture and temperature, and the relative humidity (RH) of interstitial airflow were determined intelligently in grain layers of 7.5 to 32.5 cm with 5.0 cm intervals. The change in RH of interstitial airflow in grain layers of 7.5-27.5 cm with drying time all revealed the shape of a hyperbolic line and took turns to lag. These RH lines shortened with an increased drying temperature from 45 to 65 °C and hot-air velocity from 0.7 to 1.3 m·s-1. The temperature lines were raised and shortened with an increase in drying temperature and hot-air velocity. A modified moisture diffusion exponential equation was developed to analyze the moisture desorption rate of corn kernels. For the average sorption rate curve from grain layers of 2.5-32.5 cm at 1.3 m·s-1 of hot air, the transition points from adsorption to desorption occurred at 2.4 h, 2.7 h, and 3.0 h with drying temperatures of 65 and 45 °C, respectively, and represented the earliest and largest initial desorption rates among the three hot-air velocities. The moisture desorption rate of samples increased with increasing drying temperature. Compared with the average value of grain layers, at the same hot-air velocity, the kernel effective diffusivity (Deff) values dried at 55 °C were correspondingly higher than those dried at 45 and 65 °C. At the same drying temperature, the kernel Deff values tended to increase with an increase in hot-air velocity, whereas the activation energy decreased. These results suggested that an increase in drying temperature and hot-air velocity may considerably shorten adsorption time and increase desorption rates of shelled corn in deep bed drying.

Systematic improvement of excitonic features in hydrothermally synthesized WS2 due to post-synthesis drying

WS2 nanostructures were produced by mechanically exfoliating bulk WS2 powders synthesized through a solution-based hydrothermal route using WCl6 and thioacetamide (TAA) as reactants. An unoptimized post-synthesis recipe, which constitutes the last step, is the major hindrance in achieving a reproducible and scalable production strategy of layered bulk WS2 crystals. We have reported a comprehensive study on the crystal, morphological, and luminescence properties of WS2 material which have undergone post-synthesis treatment i.e. dried at mild temperature with varied dwelling times. The as-synthesized WS2 material which used to be in distorted 1T metallic phase, due to ionic intercalation released from the organic reactants, was found to evolve crystallographically into a stable 2H semiconducting phase with increased drying temperature and dwelling time. An in-depth optical analysis of the WS2 nanostructures through PL and PLE spectroscopy revealed substantial improvement in the intensity of A and B excitonic features for the sample dried at 80 °C for 24 h, indicating a reduction in the non-radiative defect centers in the sample under the post-synthesis conditions. We believe an effective post-synthesis treatment is needed for semiconducting 2H-WS2 synthesis through the solution route to improve its crystal (i.e. structural) and optical properties for potential electronic applications.

Convective drying of shrinking hydrogel with a constant temperature stage: Experimental and numerical investigations

In this study, the convective drying characteristics of hydrogel with a constant temperature stage at different drying temperatures and initial Biot numbers (Bi0) are experimentally presented. Additionally, a numerical model coupling the mass, energy conservation equations and solid momentum balance equation is developed and validated to reveal the drying mechanisms. The results show that there are three drying stages, i.e., the temperature rise (stage I), constant temperature (stage II), and second temperature rise (stage III). Numerical results demonstrate that the duration of stage II is related to the internal moisture transport resistance which increases rapidly and leads to the end of stage II. A maximum duration of 3 h for stage II with evaporation heat flux of 268.7 W/m2 is observed at drying temperature of 35 ℃. The three drying stages persist as the drying temperature increases, but the duration of stage II decreases rapidly. In particularly, under the same drying temperatures, there is a critical Bi0 (Bi0,c) below which the drying rate increases with Bi0 significantly, but above it, the drying rate increases slightly for the same hydrogels. The duration and temperature of stage II decrease with increasing Bi0.

PSIII-5 Endosperm Hardness in Corn Affects the Digestibility of Energy and Fiber, and Increased Drying Temperature Reduces Amino Acid Digestibility

Abstract Two experiments were conducted to test the hypothesis that corn source and drying temperature influence the ileal digestibility of starch and amino acids (AA), as well as apparent total tract digestibility (ATTD) of gross energy (GE) and total dietary fiber (TDF) in diets for growing pigs. Two corn sources (i.e., soft or hard endosperm) were procured, and sources were divided into two drying batches (i.e., 35 or 120 oC). Therefore, four corn sources were used. In experiment 1, ten pigs (67.00 ± 2.98 kg) with a T-cannula installed in the distal ileum were allotted to a replicated 5 × 5 Latin square design with five diets and five periods giving ten replicates per diet. A nitrogen-free diet and four diets containing each source of corn as the only AA source were formulated. Data were analyzed in a 2 × 2 factorial arrangement of treatments using the MIXED procedure of SAS. The model included corn source, drying temperature, and the interaction between corn source and drying temperature. Results indicated that neither source nor drying temperature influenced the apparent ileal digestibility of starch in corn (Table 1), but the standardized ileal digestibility of most AA was less (P < 0.05) in corn dried at 120 oC compared with corn dried at 35 oC. In experiment 2, 40 pigs (20.82 ± 1.74 kg) were housed in metabolism crates and allotted to four diets with ten replicate pigs per diet. The four corn-based diets used in experiment 1 were also used in experiment 2. Feces and urine were collected using the marker-to-marker approach with 5-day adaptation and 4-day collection periods. Data were analyzed as explained for experiment 1. Results indicated that diets containing hard endosperm corn had greater (P < 0.05) ATTD of TDF compared with diets containing soft endosperm corn. The ATTD of GE and the concentration of metabolizable energy (ME) in hard endosperm corn were also greater (P < 0.05) compared with soft endosperm corn. Diets containing corn dried at 120 oC had greater (P < 0.05) ATTD of TDF compared with diets containing corn dried at 35 oC, but drying temperature did not influence ATTD of GE or ME. In conclusion, endosperm hardness did not influence the digestibility of AA and starch; however, drying corn at 120 oC resulted in reduced digestibility of AA. Hard endosperm corn had greater ATTD of GE and TDF, but drying temperature did not influence energy digestibility.

Temperature-dependent relationship between soil water content and electrical conductivity

Water content is a fundamental parameter for analysing soil composition and engineering behaviour. However, conceptual water content sensors cannot be used in high-temperature and high-pressure environments. To assess the suitability of using electrical conductivity (EC) as a predictor of soil water content at high temperatures, a series of EC and water content tests of clay and sand is conducted. Subsequently, the relationships between EC and water content at different temperatures are analysed. On this basis, the feasibility of eight EC models for predicting soil water content is discussed. The results show that temperature has a vital impact on the EC test of soil and EC is more sensitive to temperature than to dry density and water content. The temperature effect of soil EC is more obvious with an increase in dry density, and EC does not increase monotonically with an increase in temperature. The predicted effect of some EC models tends to be better with an increase in dry density or temperature. This research provides a reference for the EC test and model establishment of high-temperature soils.

Fitting of mathematical models in the drying of araticum (Annona crassiflora) seeds

Araticum (Annona crassiflora) seeds have relevant characteristics for industrialization due to the contents of phytosterols, carotenoids, phenolic compounds, fatty acids, and organic acids, among other components responsible for biological properties. The objective of this study was to fit different mathematical models to the experimental data, use criteria to choose the best model, evaluate the effective diffusion coefficient, and obtain the activation energy and thermodynamic properties of araticum seeds at different drying temperatures. Seeds of araticum fruits were dried at temperatures of 40, 50, 60, and 70ºC. The drying time of araticum seed decreases with increasing temperature. Among the best models fitted, the Midilli model was recommended to predict the drying curves of araticum seeds under different drying conditions. The linear model represented the effective diffusion coefficient as a function of the drying temperature. Enthalpy and entropy tend to reduce, and Gibbs free energy increases as the drying temperature increases.

Potential carbon mineralization assays are confounded by different soil drying temperatures

Measuring carbon dioxide (CO2) produced after re-wetting previously dried soil is an increasingly popular soil health assay, but there is disagreement on the optimal soil drying temperature. We tested whether soil drying temperature impacts water-extractable organic carbon (WEOC) and soil CO2 emissions following rewetting. Soils were collected from corn/soybean croplands and adjacent perennial vegetation at four sites in Iowa, USA. Soil replicates were dried at 22 °C, 35 °C, 55 °C, 85 °C, and rewetted for incubation at 22 °C. Soil WEOC and CO2 emissions after re-wetting increased nonlinearly with drying temperature. Effects on CO2 were largest after four days of incubation, but cumulative differences persisted even after 42 days. Responses of CO2 and its stable isotope ratio (δ13C) to increased drying temperature varied among sites and vegetation types, indicating shifts in C sources. Soil health assays performed with different soil drying temperatures may not be directly comparable, effects of drying temperature may vary idiosyncratically among samples, and drying at 22 °C or 35 °C as opposed to higher temperatures may be preferable to avoid increasing C availability.

Influence of bed height and drying temperature on shrimp drying characteristics using a fluidized-bed dryer

The aim of this work was to study shrimp drying in a fluidized-bed dryer to develop a process that performs better than traditional (sun dried) shrimp production. In these experiments, the influence of shrimp size (small, medium and large), bed height (h/D = 0.33, 0.66 and 1.0) and air temperature (60, 70 and 80 °C) on the drying rate were studied under a constant blower power. The experimental results showed that the moisture content of boiled shrimp decreased with an increased drying temperature due to the consequently higher temperature differential between the hot air and the shrimp. When the bed height (h/D) was reduced, shrimp moisture removal increased, but it also increased when shrimp size decreased. Moreover, the production rate of dried shrimp under a bed height h/D = 1.0 and drying temperature of 80 °C yielded the highest dried shrimp production rate of 4.83, 4.21 and 3.72 kg/h for small, medium and large shrimps, respectively.

Performance assessment of an evacuated tube solar-electric hybrid dryer for lotus seeds drying: Moisture removal behavior, GHG emission and thermodynamic analysis

A novel evacuated tube solar-electric hybrid dryer (ETSED) was developed and evaluated to contribute to global food security from the perspective of optimized processing while reducing energy consumption and greenhouse gas (GHG) emissions. The performance of the ETSED was assessed compared with solar heating drying (SHD), and mixed heating drying (MHD) at temperatures of 55, 65 and 75 °C by studying the drying behavior of the samples as well as the thermodynamic analysis and GHG emissions of the system. Results revealed that under all studied experimental conditions, the evacuated tube solar collector provided more than 60% of the thermal supply in the drying process, and significantly improved the fluid exergy. Moreover, the roller shutter mechanism and the heating tube were used together to achieve precise control of the drying temperature. In terms of thermodynamic analysis, the heating tube further enhanced the ETSED performance by providing high quality energy in combination with solar energy in MHD mode. Furthermore, compared with SHD, MHD-65 and 75 °C shortened the drying time by 10.4 and 28.2%, improved the drying efficiency by 0.7% and 6.29%, and increased the drying chamber's exergy by 14.99 and 19.36%, respectively. Remarkably, the lowest emissions of CO2 (872.06 g/kg removed water), SO2 (0.13 g/kg removed water) and NOx (0.19 g/kg removed water) were seen in the case of SHD. Based on the obtained results, the increased drying temperature in the MHD led to higher CO2, SO2 and NOX emission levels. Interestingly, when the lotus seeds were dehydrated, the accumulated electric energy generated by the photovoltaic cells almost met the electric consumption of mechanical energy. The results of this study identified the potential of ETSED equipment for food industrial production.

Effect of Pre-Test Drying Temperature on the Properties of Lateritic Soils.

The properties of residual soils, according to literature, are sensitive to the pre-test drying method given to the sample prior to testing. Similarly, residual soils such as laterites/lateritic soils are formed under various climatic conditions, hence they show different degrees of sensitivity to pretest drying method. This work is therefore carried out to elucidate the influence of pre-test drying temperature or method on the properties of three lateritic soils that developed over three different Pre-Cambrian basement complex rocks from Ado-Ekiti, SW, Nigeria. The soils were subjected to three pre-test drying temperature before conducting laboratory tests. The pre-test drying temperature considered in this study include air-drying, oven-drying at 60° C, and oven-drying at 110° C. Pre-test drying at 60° and 110° C caused particle aggregation (which reduced the soil surface are) and loss of cohesion. Consequently, this reduced the specific gravity, optimum moisture content, clay content, consistency limits, and unconfined compressive strength of the lateritic soils. The maximum dry density and sand content increased as the pre-test drying temperature increases. The pre-test drying temperature did not significantly change the plasticity classification of the soils, however, at higher pre-test temperature the soils become less plastic. The free swell index of the lateritic soils increased with increasing pre-test drying temperature (up to 60° C) before decreasing when the temperature rose to 110° C. This study has revealed the effect pre-test drying temperature may have on the properties of lateritic soils and these may produce soil properties that may not likely indicate the actual field performance of the tested soils.

Convective drying of unripe plantain: a comparative response surface methodology and genetic algorithm optimization study, certainty and sensitivity analysis

The requirement for reduction of post-harvest losses increased production, and cost-effectiveness of foods are driving continuous food process investigations. In this study, Response Surface Methodology (RSM) was utilized to understand, model, and optimize the effect of selected process factors on the moisture content (MC) of convectively dried unripe plantain fruit. For technical accuracies, Multi Gene Genetic Programming (MGGP) was also used to model the process and both MGGP and RSM models were statistically compared. Furthermore, Monte Carlo Simulation (MCS) was used to conduct sensitivity analysis of unripe plantain’s MC to each selected process factor. Results showed that increased sample thickness increased the MC while increased drying temperature and drying time decreased the MC of unripe plantain. RSM model had Chi-square, MBE, t-value, RMSE and R2 values of 15.2131, 0.7531, 7.6170, 0.9193 and 0.9674, respectively; while MGGP model had 3.0415, 0.2563, 2.6871, 0.4111 and 0.9956, respectively. Sensitivity analysis showed that sample thickness, drying temperature and drying time had +89.5 %, -10.2 % and -0.3 % contribution to the variances of MC, respectively. These results are useful in unripe plantain drying process prediction, optimization, and product standardization.

Improving the geotechnical properties of a Nigerian termite reworked soil using pretest drying conditions and sawdust ash

The environments of tropical regions favour the activities and growth of termitaria on soils and woods. The aim of this study is to determine the effect of pretest drying conditions and sawdust ash (SDA) on the strength properties of termite reworked soil for pre and post engineering construction. Twelve disturbed subsoil samples; six termite reworked soil samples and six neighboring residual soils of each of the termite reworked soils were obtained in Akungba Akoko, South-western Nigeria. The termite reworked soil and the surrounding residual soil met the Nigeria requirement of a good sub-grade soil. However, termite reworked soil shows better geotechnical ratings when compared to the surrounding residual soil samples. This result attested to the fact that termites’ activities promote forces of attraction and adhesion among the soil particles. On the addition of sawdust ash to termite reworked soil at 6% of the weight of the soil samples; the geotechnical properties of the termite reworked soils slightly improved. Again, the geotechnical properties of termite reworked soils were considered under varying pretest drying conditions; of air-dried condition as well as conditions obtained by drying the soils at 50°C ± 5, 75°C ± 5 and 110°C ± 5. The index and strength properties of the termite reworked soils improved with increase in pretest drying temperature. Statistical analysis of ANOVA shows that there is no significant statistical difference in the values of the geotechnical parameters of the sampled soils under pretest drying conditions. For Pearson’s correlation, SDA improved soil and pretest drying temperatures for fine contents with CBR and MDD values; the obtained test values of correlation are higher than the critical r value (0.497). Again we reject null hypothesis in favour of the test hypothesis.

Study on pore structure characteristics of Indonesian lignite during low temperature drying process

ABSTRACT In order to study the effect of temperature on the pore structure of lignite, liquid nitrogen adsorption and scanning electron microscopy (SEM) were used to analyze the change of pore structure of Indonesian lignite after heating, and the relationship between fractal dimension and pore structure of lignite after heating was analyzed. The effect of drying temperature on the pore structure of lignite was investigated by effective moisture diffusion coefficient and X-ray diffraction (×RD). The results show that between 40 and 160 ℃, with the increase of drying temperature, the N2 adsorption and desorption of Indonesian lignite shows a trend of first increasing and then decreasing. The fractal dimensions D 1 and D 2 of some lignites have a linear relationship with the specific surface area and average pore diameter, respectively, and the fractal dimension D 3 has a linear relationship with the average pore diameter. As the drying temperature increases, the moisture transfer resistance decreases and the effective moisture diffusivity of lignite () increases accordingly. There is a linear positive correlation between and the average pore diameter. The increase of the lignite aromatic system and the decrease of the crystallite stacking height have certain effects on the pore structure of lignite.

Nutraceutical stability in Lentinus squarrosulus after drying and frying for snack production

Pathogenesis of neurological diseases is associated with free-radical-mediated inflammatory processes. Phenolic compounds, saponin, and γ-aminobutyric acid (GABA) are nutraceuticals with neuroprotective properties. Lentinus squarrosulus is a mushroom with high proteins low calories, and nutraceuticals. This research aimed to investigate the nutraceutical contents of total phenolic compounds, saponins, γ-aminobutyric acid (GABA), and antioxidant activity in this mushroom after drying and frying for snack production. The nutraceutical contents and antioxidant activity were measured by Folin–Ciocalteu method and 2,2-diphenylpicrylhydrazyl (DPPH) assay, respectively. The stability of these nutraceuticals was also determined after drying and deep frying mushrooms in preparation for snack production. Results showed that the mushrooms after drying at 50 and 60 °C until the moisture content was below 12 % (according to Thai Community Products Standard) had water activity (aW) of 0.52 to 0.59. The dried mushrooms had lower lightness, redness, and yellowness with the increased drying temperature (p ≤ 0.05). The total phenolic content of dried mushrooms was not significantly different from that of fresh mushrooms, but saponin, GABA, and antioxidant activity were higher than in the fresh samples.

Characteristics of Red Melinjo Peel Powder Encapsulate with Spray Drying Method

Melinjo peel contains ascorbic acid, flavonoids, phenolics, lycopene, and β-carotene. The method of handling to reduce melinjo peel and preserve the active compounds is by powder encapsulation. Encapsulation is a way to protect the active compound and extend the shelf life of melinjo peel. The method used is spray drying, which can turn the liquid into a powder by heating with the help of a coating agent such as maltodextrin. The purpose of this study was to determine the difference in concentration of maltodextrin (4, 6, 8%) and temperature of spray dry (135, 145, 155, 165°C) on the physical and chemical characteristics of encapsulated powder of red melinjo peel. Analysis of red melinjo peel powder had 1.69% moisture content, 5.96 mg GAE/g total phenolic, 0.53 mg QE/g total flavonoids, 31.36% solubility, 55.98 μm particle size, and antioxidant activity (IC50) 42.694 ppm. While the analysis of the selected encapsulates, which is encapsulates with a maltodextrin concentration of 8% and a spray dry temperature of 135°C had 0,09% moisture content, 1.0683 mg GAE/g total phenolic, 99.8050% encapsulation efficiency, 0.1777 mg QE/g total flavonoid, 92.3663% solubility, 212.93 μm particle size, and 121.389, 7132 ppm of antioxidant activity (IC50). The increase in maltodextrin concentration and spray dry temperature causes the encapsulation efficiency, solubility, and particle size of encapsulation to increase but cause the moisture content, total phenolic, and total flavonoid encapsulation to decrease.