Effect of Process Variables on Spray-Dried Garlic Juice Quality Evaluated by Multivariate Statistic

Garlic juice was spray-dried at different inlet-outlet (110, 130 °C)–(60, 70, 80 °C) air temperatures and different types (gum arabic, DE-10 maltodextrins) and concentrations (0, 0.5, 0.8 g/g dm) of carrier material. Dried product quality was evaluated through moisture, water activity, powder color coordinates, and the retention of allicin and pyruvic acid. A complete 2?×?3?×?3 experimental design was developed but some treatments were experimentally nonfeasible. Then, results were analyzed by 1WANOVA and PCA. Drying conditions that maximized allicin retention were maltodextrin at 110 °C, 70 °C of inlet, outlet air temperatures, and 0.5 g carrier/g dm. Under these conditions, retentions were as follows: 76.9 % allicin and 89.9 % pyruvic acid. These results suggest that the obtained powder might be useful as a food additive or ingredient due to the higher retention levels of pyruvic acid than other types of convective drying.     

Influence of spray‐dryer air temperatures on encapsulated lime essential oil

The influence of inlet and outlet air temperatures (180–220 and 80–100 °C, respectively) on the spray drying of lime essential oil was evaluated by using a three‐level factor design. For optimisation, dryer evaporative rate, volatile oil retention, and microencapsulation efficiency were considered as response variables. The response surface analysis produced significant (P < 0.05) polynomial regression equations that were successfully fitted for all response variables, and no significant (P > 0.05) lack of fit was indicated for the reduced models, with the exception of microencapsulation efficiency. This observation confirmed an accurate fitness of the reduced response surface models to the experimental data. The multiple response optimisations indicated that an inlet air temperature of 220 °C and an outlet air temperature of 85 °C were predicted to provide the maximum evaporative rate (7.7 kg h^?1), volatile oil retention (95.7%), and microencapsulation efficiency (99.9%) in the studied ranges. Checking of the optimisation showed that with these optimal parameters, a very good closeness between the experimental and predicted values was obtained.     

Spray Drying of Spinach Juice: Characterization,Chemical Composition,and Storage

The 1st aim of this study is to determine the influence of inlet and outlet air temperatures on the physical and chemical properties of obtained powders from spinach juice (SJ) with 3.2 ± 0.2 °Brix (°Bx). Second, the effect of 3 different drying agents (maltodextrin, whey powder, and gum Arabic) on the same properties was investigated for the selected inlet/outlet temperatures (160/100 °C) which gives the minimum moisture content and water activity values. For this purpose, the total soluble solid content of SJ was adjusted to 5.0 ± 0.2 °Bx with different drying agents. Finally, the effects of different storage conditions (4, 20, and 30 °C) on the physical and chemical properties of spinach powders (SPs) produced at selected conditions were examined. A pilot scale spray dryer was used at 3 different inlet/outlet air temperatures (160 to 200 °C/80 to 100 °C) where the outlet air temperature was controlled by regulating the feed flow rate. Results showed that the moisture content, water activity, browning index, total chlorophyll, and total phenolic contents of the SP significantly decreased and pH and total color change of the SP significantly increased by the addition of different drying agents (P < 0.05). In addition, the changes in the above‐mentioned properties were determined during the storage period, at 3 different temperatures. It was also observed that the vitamin C, β‐carotene, chlorophyll, and phenolic compounds retention showed first‐order degradation kinetic with activation energy of 32.6840, 10.2736, 27.7031, and 28.2634 kJ/K.mol, respectively.     

Quality aspects of heated-air drying of soybeans

Samples of 300 g of soybean seed, variety Forrest, conditioned to 14, 16 and 18% moisture content (m.c.; w.b.), were dried for 4 hr in a small batch fluidized-bed rig with a test section of 120 mm diameter and air flow rate set at 0.03 kg/s. Air inlet temperatures of 40, 50, 55, 60, 65, 70 and 80°C were used to determine the effects on quality. Conditioned and unconditioned samples, together with samples dried in the bed for 4 hr at room temperature, served separately as controls. Samples of 25 g of the conditioned seed, sealed in test tubes, were heated for 4 hr in an air oven at 40, 45, 50, 55 and 60°C to study the effect of heating at a constant m.c.Seed germination and seedling vigour clearly indicated the onset of heat damage and showed that no single criterion was more sensitive than any other. Safe drying air temperatures of 65, 60 and 55°C were obtained for initial moisture contents of 14, 16 and 18% respectively. Heating soybeans up to 60°C at a fixed m.c. increased the susceptibility to heat damage. Oil vield, free fatty acid content and fatty acid composition were not affected by any of the heat treatments. The peroxide value, however, showed some increase at temperatures above 50°C. Fluidizing at room temperature did not affect germination.The colour of crude oil, after heat bleaching, for 50–80°C heat treatments was paler than the controls, while 40°C gave a very dark colour. Degumming of oils followed by refining removed all detectable phospholipids from all samples and produced oils paler in colour, when heat bleached, except for 80°C at 16 and 18% m.c. which produced oils slightly but noticeably darker.Soybeans were found to dry slowly compared to sunflower seed and rapeseed, and the logarithmic drying model was fitted to the various drying curves. Computer program DRIER was modified to be applicable to soybeans and some runs were carried out for a farm batch radial-flow drier. Results indicated the advantage of using a high inlet air temperature provided that seed quality is not affected.     

Evaluation of spray drying conditions on properties of microencapsulated oregano essential oil

Response surface methodology (RSM) was employed to investigate variations in powder characteristics with respect to spray drying operating parameters including both feed rates (L min^?1) and inlet temperatures (°C). Inlet temperatures around 180 °C provided the lowest values for moisture. Powder recovery was significantly affected (P < 0.10) by inlet air temperature and feed rate, where a raise in inlet temperature and feed rate resulted in higher powder recovery. No significant difference (P > 0.05) was observed for water activity, solubility and hygroscopicity between treatments. Regarding oil retention, the results showed a significant (P < 0.05) interaction between the two studied factors. A tendency for higher values of oil retention was observed when using combinations of high inlet temperatures/low feed rates and low inlet temperatures/high feed rates. Particle size distribution averaged 2.0, 8.1 and 18.3 μm for D₁₀, D₅₀ and D₉₀, respectively. The morphology of particles showed no cracks in most capsules. The results indicate that high temperature (185 °C) and moderated feed rate (0.63 L min^?1) are the best spray drying conditions.     

Heated-air drying of oilseeds

This paper describes experimental work on the drying of oilseeds. Resistance to air flow and drying rates, parameters needed for oilseed drier design, were measured. Safe drying temperatures were deter,ined in a small batch fluidized bed. Some sealed tube heating tests were also perforrned for comparison. Quality assessment was based on the effect of drying conditions on the germination of the seed and on the free fatty acid content and peroxide value of the extracted oil. Colour of the oil was also measured before and after a heat bleach test using a photometric method.Quality results indicate that germination is affected by heat above a critical drying air and seed temperature. For sunflower seed, safe drying air temperatures of 65, 60 and 55°C were obtained for initial moisture contents of 12, 14 and 16% respectively. For rapeseed, an inlet air temperature of 60°C caused no loss of germination for each initial moisture content. However, sealed tube heating of 16% m.c. sunflower and rapeseed at 60°C for 4 hr completely killed the seeds. Free fatty acid content and peroxide value were not significantly changed by the heat treatments in all cases, and oil colour after heat bleaching generally showed some improvement up to an air temperature of 70°C. At 80°C, however, substantial darkening of sunflower oil was observed.     

Optimization for encapsulation of green tea (<Emphasis Type="Italic">Camellia</Emphasis><Emphasis Type="Italic">sinensis</Emphasis> L.) extract by spray drying technology

Green tea has been credited with providing a wide variety of health benefits like higher total antioxidant, cancer prevention, and anti-irritant etc. Microencapsulation technology is used to prevent antioxidant loss during processing which involves entrapment of active material into carrier material. The experiments were designed using response surface methodology based on three level two factor (green tea extract, 10–25 % and drying inlet air temperature, 120, 130 and 140°C) central composite design. The feed emulsion was prepared with green tea extract as core material and 40 % maltodextrin concentration as wall material with the ratio of core to wall (1:2) and it was fed into the spray dryer at varied drying inlet air temperature to get encapsulated green tea extract powder. The quality characteristics were analysed such as moisture content, total antioxidant activity and total phenolic content and the process conditions were optimized using desirability function methodology. At optimum spray drying condition moisture content, total antioxidant activity and total phenolic content were found to be 3.1 % w.b., 72.91 % free radical scavenging activity by DPPH method, 57.81 mg/g of dry matter, expressed as gallic acid equivalent respectively with desirability value of 0.92.     

A Feasibility Study on the Drying of Lime Juice: The Relationship between the Key Operating Parameters of a Small Laboratory Spray Dryer and Product Quality

Concentrated lime juice with 20% total soluble solids was dried using three levels of maltodextrin (40%, 50%, and 60% solid base) and a BüCHI B-190 spray dryer. The drying air temperature and flow rate were 140 °C, 155 °C, and 170 °C and 47.1, 53.5, and 57.8 m³/h, respectively. A total of 27 experiments were conducted (in triplicate) with the feed rate, temperature, and compressed air flow for the atomizer kept constant. Analysis of the data revealed that product recovery increased when the maltodextrin in the feed and drying air flow rate were increased, but the inlet air temperature had no significant (P < 0.05) effect on powder recovery. The moisture content of the powder varied with the maltodextrin level, inlet air temperature, and air flow rate. Using scanning electron microscope images, larger particle size was observed with the increase of maltodextrin concentration. Powder bulk density also increased from 0.41 to 0.68 g/cm³, depending on the level of maltodextrin, whereas the drying air temperature and flow rate were not as effective. The results of this study are beneficial for scaling up the spray drying of lime juice to the food industry.     

Physicochemical Properties of Microencapsulated ω‐3 Salmon Oil with Egg White Powder

The objective of this study was to produce microencapsulated omega(ω)‐3 fatty acids (PUFAs) fortified egg white (EW) powders and to characterize their nutritional and physical properties. Stable emulsions (E‐SO‐EW) containing 3.43 (g/100 g) salmon oil (SO), 56.21 (g/100 g) EW, and 40.36 (g/100 g) water and a control (E‐EW) containing EW and water were prepared. E‐SO‐EW and E‐EW were separately spray dried at 130, 140, and 150 °C inlet air temperatures. This resulted in 3 microencapsulated SO fortified EW powders (SO‐EW), and 3 dried EW powders (DEW). The powders were analyzed for microencapsulation efficiency (ME), color, fatty acids methyl esters, protein, fat, moisture, ash, amino acids, minerals, microstructure, and particle size. The EPA and DHA content of SO and the ME of the powders were not affected by the inlet air temperature. The crude protein content of SO‐EW powders was approximately 24 (g/100 g) lower than dried EW powders. Leucine was the most abundant essential amino acid found in all the powders. Most of the powders’ median particle size ranged from 15 to 30 μm. The study demonstrated that microencapsulated ω‐3 salmon oil with high quality EW protein can be produced by spray drying.     

Optimization of bayberry juice spray drying process using response surface methodology

In this study, thirteen different runs according to the central composite design-response surface methodology were used to optimize the quality parameters of spray-dried bayberry juice powder. The independent variables were different levels of inlet air temperature (145.8–174.1 °C) and maltodextrin concentration (22.9–37.0%). The responses were process yield, moisture content, hygroscopicity, glass transition temperature (Tg), total color difference (ΔE), redness, retention of phenolics and anthocyanins, and antioxidant capacity. The optimum operation conditions for the highest Tg, redness, anthocyanins retention and antioxidant capacity with the lowest ΔE and hygroscopicity were obtained at inlet drying temperature of 150 °C and maltodextrin concentration of 31%. This study revealed that by applying these optimal conditions, bayberry juice powder with a 74.16% yield, 3.15% moisture content, 10.25% hygroscopicity, 41.15 °C Tg, 24.74 ΔE, 27.45 Hunter a redness, 89.55% anthocyanins retention, 77.71% phenolics retention, and 30.19 mmol Trolox equivalents/g antioxidant capacity was produced.     

Microencapsulation of Tender Coconut Water by Spray Drying: Effect of <Emphasis Type="Italic">Moringa oleifera</Emphasis> Gum,Maltodextrin Concentrations,and Inlet Temperature on Powder Qualities

The present study was aimed to evaluate the different proportions of carrier materials: Moringa oleifera gum (MG), maltodextrin (MD), and inlet temperature on the powder characteristics of encapsulated tender coconut water (TCW) by spray drying. The characterization of microparticle was studied as encapsulation efficiency, antioxidant activity, total phenolic content, moisture content, water activity, solubility, particle morphology, and encapsulation yield. The investigation was conducted using an experimental design of 2² mixes with five replicates at the center point. The encapsulation efficiency was affected by all tested variables and reached significantly (p < 0.05) higher value (94.86%) when higher MG concentration, and lower MD concentration, and inlet temperature were applied. The DPPH (53.66%) and ABTS radical scavenging activity (54.92%) was observed to be higher at the highest MG concentration (1.5%). The obtained powder retained a higher amount of phenol content (21.82 mg GAE/g) at increasing MG concentration, with decreasing MD concentration, and inlet temperature. X-ray diffraction (XRD) analysis revealed that TCW powder encapsulated with 1.5% MG exhibited higher crystalline nature as compared to microparticle encapsulated with 0.5 and 1% MG. The optimum wall material composition and inlet temperature were determined as follows: MD 30%, MG 1.5%, and 120 °C inlet temperature. Hence, our results suggest that the application of this technology could increase the use of TCW in various industrial applications and imply MG as a potent candidate for microencapsulation of food materials.     

Characterization of hot-air drying and infrared drying of spearmint (<Emphasis Type="Italic">Mentha spicata</Emphasis> L.) leaves

In this study, spearmint leaves were dried using hot-air (HA) and infrared (IR) techniques. Dried products were comprehensively analyzed for their drying time, specific energy consumption (SEC), rehydration, essential oil content and color changes. The IR drying process was carried out at radiation intensity levels of 1562, 3125 and 4688 W/m², emitter to sample distances of 10, 15 and 20 cm and air temperatures of 30, 40 and 50 °C. For HA drying, three levels of air temperature (30, 40 and 50 °C) and air velocity (0.5, 1 and 1.5 m/s) were applied. The results indicated that drying time, SEC and color changes were lower in IR drying of spearmint than in HA drying. IR drying gave the highest essential oil content (0.95 %) and rehydration ratio (0.788 kg water/kg dry matter (DM)). Totally, it was observed that IR drying of spearmint resulted in better quality preservation and had lower energy costs in comparison to HA drying.     

The nutritive value of porcine blood plasma concentrates prepared by ultrafiltration and spray Drying

Concentrated solutions of porcine blood plasma proteins, prepared by centrifugation and ultrafiltration⁴ were spray dried directly at air inlet temperatures of 154, 170.3, 225 and 243.2 °C. Spray dried concentrates contained ca 86–90% protein, ca 2–7% moisture and ca 5% minerals. The overall amino acid composition of the plasma proteins compared favourably with that of FAO whole egg protein.¹² Although the values of essential amino acids generally fell below the egg values, the only serious limitations were in the content of isoleucine (less than half of the egg value). The chemical score (CS) and essential amino acid index (EAAI) were 49.1 and 70.1 respectively. Rats fed on a diet containing plasma concentrate as the sole protein source showed a net weight increase. NPU carcass for plasma protein was 65.8 ± 1.9 compared with a value of 72.1 ± 0.4 for a casein control. An inverse correlation between denaturation status of plasma proteins and spray drying temperature was found. The percent denaturation as measured on pH 4.0 filtrates increased from 8.4% at an air inlet temperature of 154 °C to 48.6% at a temperature of 243.2 °C. A similar inverse relationship was found between the available lysine content of plasma proteins and spray drying temperature. A maximum decrease in percent lysine availability of 16% was found at an air inlet drying temperature of 243.4 °C.     

喷雾干燥法制备银杏油微胶囊的研究

以银杏中主要活性物质类黄酮的微胶囊化效率为考察指标,对银杏油进行微胶囊化处理,探讨喷雾干燥法制备银杏油微胶囊的工艺。结果表明,最佳微胶囊原料配方为：阿拉伯胶与β- 环糊精的比例为1:1(m/m),芯材与壁材的比例为1:3(m/m),料液浓度为25%(m/V),单甘脂为0.1%;最佳喷雾干燥工艺条件为：进料流量30ml/min,进风温度180℃,出风温度80℃。在此工艺条件下微胶囊化银杏油的效率可达到90.66%;制备的银杏油微胶囊为黄色或淡黄色细小颗粒,水分含量2.28%,密度0.82g/cm3,溶解度98.10%,黄酮含量5.73%,包埋效果良好。     

Study of the antioxidant properties of extracts obtained from nopal cactus (Opuntia ficus-indica) cladodes after convective drying

BACKGROUND: The process of convective drying was evaluated in terms of the bioactive compounds contained in nopal samples before and after dehydration. Total polyphenol, flavonoid, flavonol, carotene and ascorbic acid contents were determined in undehydrated and dehydrated samples. Two drying temperatures (45 and 65 °C) and two air flow rates (3 and 5 m s^?1) were evaluated. The rheology of samples under the best drying conditions was also studied, since it provides important information regarding processing (mixing, flow processing) as well as the sensory attributes (texture) of rehydrated samples. RESULTS: Non‐Newtonian shear‐thinning behaviour was observed for samples dried at 45 °C, while samples dried at 65 °C showed shear‐thickening behaviour, possibly caused by thermal chain scission of high‐molecular‐weight components. CONCLUSION: The best conditions for bioactive compound preservation were a drying temperature of 45 °C and an air flow rate of 3 m s^?1, resulting in 40.97 g phenols, 23.41 g flavonoids, 0.543 g β‐carotene and 0.2815 g ascorbic acid kg^?1 sample as shown in table 3. Copyright © 2011 Society of Chemical Industry     

Optimisation of a pilot‐scale spray drying process for probiotic yoghurt,using response surface methodology

The influence of drying air temperatures, drying air flow rate and feed flow rate on percentage survival rate (% SR) of starter and probiotic bacteria, moisture content, water activity and colour of probiotic yoghurt powder produced using a pilot‐scale spray dryer was investigated. Optimisation of spray drying conditions was achieved based on the desirability value. Results showed that inlet air temperature, drying air flow rate, feed flow rate and outlet air temperature of 150 °C, 478 m³/h, 2 L/h and 63.3 °C, respectively, were optimal conditions to produce powder that meets quality specifications and with a satisfactory% SR.     

Modeling some thermal and physical characteristics of terebinth fruit under semi industrial continuous drying

In this research, the effect of different drying conditions on thermal and physical properties of terebinth fruit was studied. Experiments were conducted with a semi industrial continuous dryer in air temperature levels of 45, 60, 75 °C, air velocity levels of 1, 1.5 and 2 m/s and belt linear speeds of 2.5, 6.5, 10.5 mm/s. Results showed that the Midilli model had the best performance in predicting the moisture ratio. Effective moisture diffusivity of terebinth fruit during experiments was 6.48 × 10^?11–2.34 × 10^?10 m²/s achieved. Activation energy of the samples between 25.45 and 35.16 kJ/mol was obtained. The highest and lowest values of specific energy consumption 65.2 and 10.5 GJ/kg were calculated. Maximum value of shrinkage (16.70 %) was calculated at air temperatures of 75 °C and minimum value (12.34 %) was achieved at air temperature of 45 °C. After drying, total color difference was increased, and hue angle and chroma were decreased. Rupture force for dried terebinth between 80.15 and 112.68 N mm were calculated.     

Influence of Wall Material and Inlet Drying Air Temperature on the Microencapsulation of Fish Oil by Spray Drying

Several single and composite milk-originated wall materials were used to microencapsulate fish oil via spray drying at various inlet drying air temperatures. Skim milk powder (SMP), whey protein concentrate, whey protein isolate (WPI), 80% WPI?+?20% milk protein concentrate, and 80% WPI?+?20% sodium caseinate (NaCas) were applied as the wall for capsules generated at drying air temperatures of 140, 160, and 180 °C. The higher the drying air temperature, the higher was the particle size, encapsulation efficiency, and peroxide value and the lower was the moisture content and bulk density. The microcapsules prepared with SMP showed the highest encapsulation efficiency and lowest peroxide value for the oil due to the presence of lactose in its chemical composition. Differential scanning calorimetry and Fourier transform infrared analyses indicated the absence of any significant interaction between SMP and fish oil.     

Determination of ideal water activity and powder temperature after spray drying to reduce Lactococcus lactis cell viability loss

Spray drying presents a promising technology for preserving bacteria despite a low survival rate of heat-sensitive cultures when subjected to the drying process. The aim of this study was to determine the ideal powder parameters [water activity (Aw) and temperature (T°C_powder)] needed to produce dehydrated Lactococcus lactis ssp. lactis with a high viability after drying. Cell concentrates injected into a spray dryer using varying cell concentrate flow rates (F_concentrate = 0.3 to 1.0 kg/h), inlet air temperatures (T°C_{inlet air} = 115 to 160°C), and outlet air temperatures (T°C_{outlet air} = 70 to 115°C) resulted in powders with different values of Aw and T°C_powder, and levels of cell viability loss. Lower cell viability reduction (∼0.43 log cycles) was obtained in conditions of Aw = 0.198 and T°C_powder = 52°C, which can be met by using T°C_{inlet air} ∼126°C and T°C_{outlet air} = 88.9°C regardless of F_concentrate values. After 60 d of storage at room temperature, cell population varied from 7.0 × 10⁵ to 1.1 × 10⁸ cfu/g. The initial powder Aw had no influence on cell death rate, but T°C_powder influence was observed. The approach adopted in this study can be applied to other bacteria or spray dryer equipment to determine optimal drying conditions.     

均质压力及喷雾干燥温度对鱼油微胶囊化的影响

采用辛烯基琥珀酸酯淀粉Hi-Cap100和葡萄糖浆作为鱼油微胶囊的壁材。研究了不同均质压力下乳化液黏度、粒径和粒径分布规律,考察了不同均质压力下乳化液特性与鱼油微胶囊包埋率、表面油含量之间的相关性,探讨了喷雾干燥温度对包埋率和鱼油过氧化值(POV)的影响。研究结果表明,随着均质压力的增加,乳化液黏度和平均粒径逐渐减小,而粒径分布离散度总体呈下降趋势,在40MPa时最小,说明此时粒径分布均一性最佳;喷雾干燥温度增加时,鱼油包埋率先增后减,POV值先减后增,在进/出口温度为140℃/70℃时有最高的包埋率和最低的POV值。通过分析确定最佳工艺参数如下,均质压力为40MPa,喷雾干燥进口温度为140℃,出口温度为70℃。在上述最适工艺条件下,鱼油微胶囊平均粒径为5.97μm,表面油含量为2.03%,微胶囊化包埋率为95.6%,在扫描电镜下观察微胶囊表面和内部结构良好,具有良好的包埋效果。