Influence of the washings on the thermal properties of polyurea-urethane microcapsules containing xylitol to provide a cooling effect

In this report, the preparation and performance of microcapsules interacting with the absorbed water to promote a cooling effect were investigated. The microcapsules containing xylitol were prepared from xylitol and diphenyl methylene diisocyanate (MDI) by an interfacial polymerization process. The microencapsulated xylitol was characterized by scanning electron microscopy (SEM) to illustrate its porous surface structure and its morphology. The influence of the drying process after washing was analyzed by differential scanning calorimetry (DSC) prior to the determination of the heat of solution. The results show the perspectives of the usage of these microcapsules as a reversible cooling agent for moisture management.     

微胶囊包埋技术在番茄胡萝卜复合粉中的应用

以番茄胡萝卜为原料应用微胶囊技术通过喷雾干燥制取复合粉.采用单因素对比试验以及L9(34)正交优化试验的方法最终确定喷雾干燥的最佳工艺条件:包埋剂麦芽糊精添加系数为2.0g·mL-1,进口温度为130℃,风速1.0m3·min-1,喷射压力为210kPa,进料量为4.5×180mL·h-1.     

Effect of trehalose and lactose as cryoprotectant during freeze‐drying,in vitro gastro‐intestinal transit and survival of microencapsulated freeze‐dried Lactobacillus casei 431 cells

A novel microencapsulation technique for Lactobacillus casei 431 cells was developed, and the bacterial stability was studied. Cryoprotective solutes were incorporated in the encapsulation mix to improve freeze‐drying survival. The losses of viable cells during drying were recorded as 1.7, 0.84 and 0.38 log Colony‐forming units (cfu)/g for control and samples with trehalose and lactose, respectively. During the simulated gastric‐intestinal transit, trehalose and lactose contributed to higher survivals of 3.1 and 3.0 log cfu/g, respectively, in gastric fluid and 1.3 log and 0.9 log cfu/g, respectively, in 1% bile extract solution. Higher temperature storage was found to be detrimental for cell viability.     

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.     

肉桂醛微胶囊的制备工艺

研究了以阿拉伯树胶和麦芽糊精为壁材,喷雾干燥制备微胶囊化肉桂醛的工艺条件,探讨了壁材组成、乳化剂用量、固形物浓度,芯壁化,进风温度、进料速度、喷射压力等对微胶囊化效果的影响,经过正交试验,确定了最佳工艺条件。     

食品和饲料添加剂工业中微胶囊产品的特性研究

本文介绍了食品和饲料工业中微胶囊技术，以及微胶囊化产品微观结构的影响因素，并介绍了有关微胶囊产品稳定性、分散性、扩散性方面的基本动力模型。     

Yeast-cell-based microencapsulation of chlorogenic acid as a water-soluble antioxidant

The water-soluble antioxidant, chlorogenic acid, was successfully encapsulated in the low cost-high volume yeast cells for the first time, as characterized by FT-IR spectra and fluorescence micrograph of the yeast cells, chlorogenic acid and microcapsule.

The encapsulation efficiency (EE) of yeast cells could be enhanced significantly (P < 0.001) by the treatment of yeast cells with plasmolyser before encapsulation. Also, the release characteristics of the obtained yeast-encapsulated chlorogenic acid were evaluated, and its storage stability as a powder were investigated at 25 °C/75% relative humidity (RH), 25 °C/90% RH and 60 °C. It could be clearly demonstrated that no chemical changes had taken place during the encapsulation, and the yeast-encapsulated chlorogenic acid exhibited a good stability. This study would be helpful to promote the application of chlorogenic acid. The new yeast-cell-based encapsulation protocol may have some general interests for maintaining the stability of other water-soluble substances.     

Survivability of probiotics encapsulated in alginate gel microbeads using a novel impinging aerosols method

Encapsulation of probiotic bacteria in cross-linked alginate beads is of major interest for improving the survivability in harsh acid and bile environment and also in food matrices. Alginate micro beads (10-40 μm) containing the probiotics Lactobacillus rhamnosus GG and Lactobacillus acidophilus NCFM were produced by a novel technique based on dual aerosols of alginate solution and CaCl₂ cross linking solution. Extruded macro beads (approximately 2 mm diameter) produced by the conventional method and micro beads produced by novel aerosols technique offered comparable protection to L. rhamnosus in high acid and bile environment. Chitosan coating of micro beads resulted in a significant increase in survival time of L. rhamnosus from 40 to 120 min in acid condition and the reduction in cell numbers was confined to 0.94 log over this time. Alginate macro beads are more effective than micro beads in protecting L. acidophilus against high acid and bile. Chitosan coating of micro beads resulted in similar protection to L. acidophilus in macro beads in acid and extended the survival time from 90 to at least 120 min. Viability of this organism in micro beads was 3.5 log after 120 min. The continuous processing capability and scale-up potential of the dual aerosol technique offers potential for an efficient encapsulation of probiotics in very small alginate micro beads below sensorial detection limits while still being able to confer effective protection in acid and bile environment.     

玻璃态微胶囊化技术

本文主要阐述玻璃态微胶囊化技术的概念、基本原理与方法、影响因素及其在食品工业中的应用。     

Stability of encapsulated olive oil in the presence of caffeic acid

The aim of this study was to investigate the influence of microencapsulation and addition of the phenolic antioxidant caffeic acid (CA) on the storage stability of olive oil. Olive oil in the absence or presence of 300 ppm CA was encapsulated in 1.5% w/w sodium alginate shells. Encapsulated oil (with/without added CA) and unencapsulated oil were stored at 20 or 37 °C for 30 days and then subjected to stability and quality evaluation based on peroxide value (PV), p-anisidine value (p-AV), Totox value, free fatty acid (FFA), total extractable phenolic content (TEPC), and fatty acid composition. The CA addition increased the stability and TPC of the final oil product. Oxidation changes were generally slower in the encapsulated oil samples. Both encapsulation and addition of CA preserved unsaturated fatty acids (UFAs) including C18:1 (omega-9 FA), C18:2 (omega-6 FA) and C18:3 (omega-3 FA). We conclude that the current oil encapsulation method using alginate microspheres could be a feasible approach to increasing olive oil stability. The addition of CA to olive oil not only provides additional protection to the oil, but also improves the nutritional values of the final oil product in terms of elevated TEPC and desired UFAs.