Influence of emulsion composition and inlet air temperature on the microencapsulation of flaxseed oil by spray drying

The objective of this work was to study the influence of some process conditions on the microencapsulation of flaxseed oil by spray drying. The process was carried out on a mini spray dryer and gum Arabic was used as wall material. Seventeen tests were made, according to a central composite design. Independent variables were: inlet air temperature (138-202 °C), total solid content (10-30% w/w) and oil concentration with respect to total solids (10-30% w/w). Encapsulation efficiency, lipid oxidation and powder bulk density were analyzed as responses. Powder morphology and particle size distribution were also analyzed. The feed emulsions were characterized with respect to droplet size and viscosity. Higher solid content and lower oil concentration led to higher encapsulation efficiency and lower lipid oxidation, which was related to the higher emulsion viscosity and lower droplets size. Increasing drying temperature resulted in higher lipid oxidation. Bulk density increased when higher solid content and lower inlet air temperature were used. The particles were rounded and shriveled, and their mean diameter was mainly affected by total solid content.     

Microencapsulation of fish oil by spray drying--impact on oxidative stability. Part 1

The aim of this study was to investigate the influence of spray drying on oxidative stability of dried microencapsulated fish oil (DMFO) coated with modified cellulose. DMFO samples were obtained by spray drying of prepared emulsions consisted of water solution of modified cellulose and fish oil. Appearance and size of particles were measured by electron microscopy and laser light microsizer. The oxidative stability of samples was evaluated by peroxide value measurements. Additionally the influence of different antioxidant substances on oxidative stability of the fish oil was investigated. It was observed that oxidation changes were much slower in bulk fish oil compared to DMFO. The most important factor determining shelf-life of the product was the access to air. It can be concluded, that the production of fish oil microcapsules by spray drying technique is possible, however its oxidative stability is not improved.     

Microencapsulation of flax oil with zein using spray and freeze drying

Microencapsulation of flax oil was investigated using zein as the coating material. Central Composite Design - Face Centered was used to optimize the microencapsulation with respect to zein concentration (x₁) and flax oil concentration (x₂) using spray drying. Also, freeze drying was carried out at two zein:oil ratios. The quality of microcapsules was evaluated by determining encapsulation efficiency, flowing properties (Hausner ratio), and evaluating the morphology with scanning electron microscopy. The response surface model for microencapsulation efficiency showed a high coefficient of determination (R² = 0.992) and a non-significant lack of fit (p = 0.256). The maximum microencapsulation efficiencies were 93.26 ± 0.95 and 59.63 ± 0.36% for spray drying and freeze drying, respectively. However, microcapsules prepared by spray and freeze drying had very poor handling properties based on the Hausner ratio. The bulk density decreased with an increase in zein concentration at the same flax oil concentration. The morphology of the flax oil microcapsules depended on the zein:flax oil ratio and the process used for microencapsulation. Flax oil microcapsules prepared by spray drying appeared to be composed of heterogeneous spheres of various sizes at high zein:flax oil ratios. Microcapsules prepared by freeze drying resulted in agglomerated small spheres. These microcapsules might find a niche as functional food ingredients.     

Production and properties of casein hydrolysate microencapsulated by spray drying with soybean protein isolate

The aim of this work was to encapsulate casein hydrolysate by spray drying with soybean protein isolate (SPI) as wall material to attenuate the bitter taste of that product. Two treatments were prepared: both with 12 g/100 g solids and containing either two proportions of SPI: hydrolysate (70:30 and 80:20), called M1 and M2, respectively. The samples were evaluated for morphological characteristics (SEM), particle size, hygroscopicity, solubility, hydrophobicity, thermal behavior and bitter taste with a trained sensory panel using a paired-comparison test (non-encapsulated samples vs. encapsulated samples). Microcapsules had a continuous wall, many concavities, and no porosity. Treatments M1 and M2 presented average particle sizes of 11.32 and 9.18 μm, respectively. The wall material and/or the microencapsulation raised the hygroscopicity of the hydrolysate since the free hydrolysate had hygroscopicity of 53 g of water/100 g of solids and M1 and M2 had 106.99 and 102.19 g of water/100 g of solids, respectively. However, the hydrophobicity decreases, the absence of a peak in encapsulated hydrolysates, and the results of the panel sensory test considering the encapsulated samples less bitter (p < 0.05) than the non-encapsulated, showed that spray drying with SPI was an efficient method for microencapsulation and attenuation of the bitter taste of the casein hydrolysate.     

Influences of different carbohydrates as wall material on powder characteristics,encapsulation efficiency,stability and degradation kinetics of microencapsulated lutein by spray drying

In the present study, seven carbohydrates were selected as encapsulant for preparing lutein microencapsulated powders (LMPs). The surface morphology, physical properties, encapsulation efficiency, and thermo- and storage stability of LMPs were studied to determine the protective effects of different carbohydrates on microencapsulated lutein during spray drying and storage. Results on powder characteristics indicated that the crystal inhibition of wall material in spray drying was necessary for decent encapsulation efficiency, and higher glass transition temperature of wall material could cause high product yield. In stability assessment, degradation kinetics of different LMPs at two different temperature conditions were analysed, revealing that inulin could provide more effective protection compared with the other carbohydrate. Our results suggested that the different carbohydrates had great influence on the quality of LMPs, and inulin could be considered as an alternative for the generation of LMPs to enhance storage stability and extend shelf life of this bioactive product.     

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。     

Oxidative stability of alpha‐linolenic acid (ω‐3) in flaxseed oil microcapsules fortified market milk

The oxidative stability of α‐linolenic acid (ALA) was investigated in market milk fortified with flaxseed oil microcapsules. Milk was fortified at levels of 1, 2 and 3 g/100 mL using flaxseed oil powder, and optimised on the basis of sensory scores. No significant difference was observed between the control, 1 and 2 g/100 mL fortified milk samples. Therefore, 2 g/100 mL fortified milk was further evaluated for oxidative stability, fatty acids profile and sensory acceptability during 5 days of storage. The fortified milk was oxidatively stable and sensorially acceptable, retaining ~10.35% ALA, which indicated that 250 mL of milk could meet ~46% of the RDA for ω‐3 fatty acids.     

Study on microencapsulation of curcumin pigments by spray drying

Curcumin has strong coloring power, safety and innocuity, comprehensive pharmacological function, but its low stability and water insoluble limit its application. Curcumin microcapsules were prepared by spray-drying process using porous starch and gelatin as wall material here. Results showed optimal condition as follows: the ratio of core and wall material of 1/30, embedding temperature of 70 °C, embedding time 2 h, inlet gas temperature of 190 °C, feed flow rate 70 mL/min and drying air flow 70 m³/h, at which the microencapsules had good encapsulation efficiency. The stability of microencapsulation curcumin against light, heat, pH was effectively improved and its solubility was increased greatly. This study would be helpful to the industrial application of curcumin.     

Effects of the drying method on the oxidative stability of the free and encapsulated fractions of microencapsulated sunflower oil

The influence of the drying method, freeze-drying and spray-drying, on the oxidative stability of microencapsulated sunflower oil depended on the type of encapsulation matrix. For a dairy-type matrix, formed by sodium caseinate and lactose, greater losses of tocopherols were detected during spray-drying, but both the free and encapsulated oil fractions were more stable against lipid oxidation than their freeze-dried counterparts. Results suggested that the free oil was also constituted by droplets that preserved their interfacial membrane and were protected by the matrix. Therefore, the free oil was not necessarily the non-encapsulated fraction. For a matrix constituted by gelatine, maltodextrin and sucrose, the emulsion showed low stability and a great destabilisation during spray-drying. No significant effect of the drying method on the oxidative stability of the encapsulated fraction was found with this matrix, but the free oil of the spray-dried sample oxidised faster, probably due to the emulsion destabilisation observed, which gave rise to a great amount of oil on the particle surface as a consequence of large droplets poorly stabilised.     

壁材种类及浓度对高载量紫苏籽油微胶囊特性的影响

为筛选出适于喷雾干燥法制备高载量（50%）紫苏籽油微胶囊的壁材,本文以可溶性大豆多糖、阿拉伯胶、Capsule淀粉、纯胶2000、HI-CAP 100为壁材,研究了壁材种类及其浓度对紫苏籽油微胶囊特性的影响。结果表明,壁材浓度20%时,纯胶2000和HI-CAP 100作为壁材制备的微胶囊产品的表面油含量较低（分别为3.05%、3.31%）,且包埋率较高（分别为93.86%、93.33%）,包埋效果明显优于其他壁材。因此,纯胶2000和HI-CAP 100是制备高载量紫苏籽油微胶囊的优良壁材。      

Sensory characterisation and oxidative stability of walnut oil

This study was carried out in order to probe the extent of oxidative and flavour stability of walnut oil (WO) under conditions normally used for selling in retail markets, during a period of four months. Fresh WO was characterised by higher intensity ratings of nutty and oily film, and lesser ratings for pungent and astringent attributes. Low and similar values for sweetness and bitterness were also detected. The ratings for negative attributes (oxidised and painty) were close to zero. During the long‐term storage period, the extent of the oil oxidative degradation was more pronounced than flavour attributes deterioration. Peroxide values (PV), conjugated dienes and trienes increased significantly throughout the storage period, whereas tocopherol content and oxidative stability index showed significant reductions. Minor changes were observed in the overall flavour stability. Using a PV of 10 mequiv. O₂ kg^?1 oil as a quality criterion, WO stored in transparent glass bottles, exposed to fluorescent light (1100 Lux) and room temperature conditions, without addition of any antioxidant, could maintain an acceptable quality until two months of storage.     

Bifidobacterium Bb-12 microencapsulated by spray drying with whey: Survival under simulated gastrointestinal conditions,tolerance to NaCl,and viability during storage

Bifidobacterium Bb-12 was microencapsulated by spray drying with whey. This present work investigated the survival of these microcapsules under simulated gastrointestinal conditions, as well as their tolerance to NaCl and their viability during storage. The results showed a small decrease in the viability of microencapsulated Bifidobacterium at low pH. In relation to the exposure of Bifidobacterium to bile, microencapsulation with whey did not protect the probiotic cells; however, the viability of the microcapsules remained >6 log cfu/g, even after 24 h of incubation at the highest bile concentration analyzed. No growth was noted with either the free cells or the microencapsulated cells on MRS-LP with NaCl. The viability of the microcapsules stored at 4 °C remained high and constant for 12 weeks. When the microcapsules were added to a dairy dessert, the probiotic count remained above 7 log cfu/g for 6 weeks. Therefore, whey is a promising encapsulating agent for Bifidobacterium Bb-12.     

亚麻籽油粉末油脂壁材及抗氧化剂选择的研究

将麦芽糊精分别与乳清粉、变性淀粉(エムルスタ-500A,CAPSUL)、阿拉伯胶、乳糖以4∶1的比例混合作为壁材,用喷雾干燥法制备亚麻籽油粉末油脂。通过乳状液分析及粉末油脂分析得出:以麦芽糊精与乳清粉混合作为壁材的粉末油脂氧化稳定性最好。比较了抗坏血酸棕榈酸酯(AP)、生育酚(VE)、特丁基对苯二酚(TBHQ)在粉末油脂及纯油体系中的抗氧化效果,结果表明TBHQ的抗氧化效果最佳。     

婴儿配方食品调和油微胶囊化的研究

依据母乳脂肪中主要脂肪酸含量,通过气相色谱和建立多元方程来调配调和油,并用喷雾干燥法对调和油微胶囊化进行研究,探索了工艺条件,找出了最佳工艺参数。     

洋葱精油微胶囊喷雾干燥制备工艺优化及释放性能分析

采用喷雾干燥技术,研究制备条件对洋葱精油微胶囊化的影响,以包埋率为指标,通过响应面分析法,优化微胶囊的制备工艺;对比喷雾干燥前后洋葱精油主要成分硫代亚磺酸酯含量的变化,并测定洋葱精油微胶囊的质量指标,对微胶囊制备工艺进行分析;对微胶囊实施体外模拟试验,同时对不同贮藏温度下精油的挥发率进行研究,分析微胶囊的释放效果及稳定性。结果表明：微胶囊最佳制备工艺为乳化温度61 ℃、进风温度177 ℃、进料流量900 mL/h,该条件下微胶囊的包埋率为92.06%,喷雾干燥之后洋葱精油硫代亚磺酸酯保留率值与理论值相近;微胶囊的出粉率、含水率、密度、粒径及感官评分分别为22.34%、3.12%、0.79 g/cm³、15.3 μm和92,出粉率高,含水量低,品质较佳,在胃肠液中的控释效果较好,易于吸收且刺激性小,洋葱精油微胶囊的释放过程与Avrami’s方程拟合良好,随着温度的升高微胶囊释放速率常数上升,微胶囊应在低温条件下贮藏。     

亚麻籽胶为壁材制备枸杞油微胶囊的研究

采用喷雾干燥法制备枸杞油为芯材、亚麻籽胶为壁材的微胶囊,并以微胶囊化效率和含油率为考察指标,考察了制备工艺。结果表明,最佳微胶囊原料配方为:壁材与芯材的比例为(m:m)2:3;最佳喷雾干燥工艺条件:进风温度为180℃,出风温度为70℃,雾化器转速24000r/min,进料速度为46.21mL/min。在此工艺条件下枸杞油的微胶囊化效率为93.29%,含油率为45.62%。     

Investigations into the stabilization of a volatile aroma compound using a combined emulsification and spray drying process

The aromatic compound 3-methylbutyraldehyde (3-mba) was stabilized using a combined emulsification (W₁/O/W₂) and spray drying process. The process suitability and the encapsulation properties of eight materials were evaluated. Whey protein concentrate (WPC), sodium octenyl succinate modified starch (modified starch 1), maltodextrin, and gum Arabic (GA) were found to be the best process-adapted microencapsulation materials. These materials were chosen for further experiments in which the influence of the solids content on flavor intensity and flavor retention during storage were determined. The amount of encapsulated 3-mba increased with increasing solids content from 40–50% using WPC, modified starch 1, and maltodextrin. Microcapsules with GA reached the maximum value of encapsulated 3-mba at 45% solids. After 11 days of storage, flavor retention decreased in the following order: GA > modified starch 1 > WPC ∼ maltodextrin. Finally, the spray drying process was optimized by design of experiments (DoE). The optimized parameters were a feed temperature of 40 °C, a dry mass in W₂ of 60%, and an amount of W₁/O of 40% using modified starch 1.     

Effect of spray drying and storage on the stability of bayberry polyphenols

Bayberry juice was spray dried with maltodextrin (DE 10) as a carrier and then stored under different temperature and water activities (aw). The retention of the total phenolic content (TPC) and total anthocaynins (ACN) during the drying process were about 96% and 94%, respectively, suggesting spray drying was a satisfactory technique for drying heat sensitive polyphenols. Under an aw of 0.11–0.44, the TPC and ACN in bayberry powders decreased by about 6–8% and 7–27%, respectively, after 6 months storage at 4 °C; at 25 °C for the same storage period the decreases were between 6–9% and 9–37%, respectively, while at 40 °C the decreases were in the range 7–37% and 9–94%. The anthocyanin component was more readily degraded relative to other phenolic compounds. The results suggest that bayberry powder should be stored at less than 25 °C and aw of 0.33, on account of greater polyphenol stability under such conditions.