Functional Properties and Oxidative Stability of Flaxseed Oil Microencapsulated by Spray Drying Using Legume Proteins in Combination with Soluble Fiber or Trehalose

The objective of this study was to evaluate the potential of double wall material combinations, using legume protein (soy protein isolate and pea protein isolate) in combination with wheat dextrin soluble fiber or trehalose, as alternative materials for microencapsulation of flaxseed oil by spray drying. The obtained preparations, with oil content of 35%, were fine and difficult flowing powders, regardless of their composition. The 1% addition of silica to the powders significantly reduced their cohesiveness and improved their flowability. The efficiency of microencapsulation, calculated based on oil fat content, ranged from 62 to 98% and was higher in the powders with trehalose and in the powders containing soy protein. Effective protection against oxidation of microencapsulated oil was achieved in the protein-trehalose matrix, especially in the case of the vacuum-packed powders with pea protein during storage at refrigeration temperature. Replacing trehalose with soluble fiber enabled formation of powders less susceptible to caking under conditions of increased humidity, but it resulted in decreased microencapsulation efficiency. The combination of pea protein/carbohydrate resulted in the formation of microcapsules with porous structure, especially in the system with soluble fiber. With time, the structure of the primary emulsions and those reconstituted from powders containing pea protein changed from liquid to greasy and paste-like.     

喷雾干燥法制备微胶囊化粉末油脂的研究进展

粉末油脂是食品微胶囊技术的产品,因其具有方便操作、稳定性好和货架期长等特点,而被广泛应用于食品工业中.目前用于食品工业制造粉末油脂的微胶囊化方法主要是喷雾干燥法.文章就粉末油脂的特点、喷雾干燥制备粉末油脂的方法及壁材选择等进行总结,并提出这项技术在中国调味品工业中的应用.     

Impact of Milk Protein Type on the Viability and Storage Stability of Microencapsulated Lactobacillus acidophilus NCIMB 701748 Using Spray Drying

Three different milk proteins — skim milk powder (SMP), sodium caseinate (SC) and whey protein concentrate (WPC) — were tested for their ability to stabilize microencapsulated L. acidophilus produced using spray drying. Maltodextrin (MD) was used as the primary wall material in all samples, milk protein as the secondary wall material (7:3 MD/milk protein ratio) and the simple sugars, d-glucose and trehalose were used as tertiary wall materials (8:2:2 MD/protein/sugar ratio) combinations of all wall materials were tested for their ability to enhance the microbial and techno-functional stability of microencapsulated powders. Of the optional secondary wall materials, WPC improved L. acidophilus viability, up to 70 % during drying; SMP enhanced stability by up to 59 % and SC up to 6 %. Lactose and whey protein content enhanced thermoprotection; this is possibly due to their ability to depress the glass transition and melting temperatures and to release antioxidants. The resultant L. acidophilus powders were stored for 90 days at 4 °C, 25 °C and 35 °C and the loss of viability calculated. The highest survival rates were obtained at 4 °C, inactivation rates for storage were dependent on the carrier wall material and the SMP/d-glucose powders had the lowest inactivation rates (0.013 day^?1) whilst the highest was observed for the control containing only MD (0.041 day^?1) and the SC-based system (0.030 day^?1). Further increase in storage temperature (25 °C and 35 °C) was accompanied by increase of the inactivation rates of L. acidophilus that followed Arrhenius kinetics. In general, SMP-based formulations exhibited the highest temperature dependency whilst WPC the lowest. d-Glucose addition improved the storage stability of the probiotic powders although it was accompanied by an increase of the residual moisture, water activity and hygroscopicity, and a reduction of the glass transition temperature in the tested systems.     

Characterization of Selected Materials for Lemon Oil Encapsulation by Spray Drying

Methods were developed for characterizing various polymers for their capacity to retain high amounts of encapsulated lemon oil. The testing protocol included evaluation of polymer isothermal drying curves, fluid flow characteristics, lemon oil encapsulation efficiency, emulsion stability, maximum loading values, vapor phase diffusive flux and extractable oil. Of the encapsulation matrices examined, the commerical product, Capsul, was best overall, with excellent retention of volatile oil, emulsion stability and load capacity. An oxidized, phenylalanine-reacted starch rated best of the experimental materials.     

Impact of Wall Materials on Physicochemical Properties of Microencapsulated Fish Oil by Spray Drying

The aim of the present study was to investigate the effect of wall materials composition on physicochemical characteristics of fish oil microcapsules produced by spray drying (180 °C). Four different combination of coating materials (fish gelatin, chitosan, combination of gelatin and chitosan, and a mixture of microbial transglutaminase (MTGase) with maltodextrin) were applied to two different fish oils to produce 40 % solid emulsions. Scanning electron microscopy and extraction of surface and encapsulated oils revealed that fish gelatin provided the highest preserving effect on the covering fish oil. Meantime, addition of MTGase to gelatin could also increase this ability and reveled less surface oil than chitosan treatment (2.63 and 2.80 % versus 4.66 and 5.23 %, respectively; P?<?0.05). Mixture of gelatin and maltodextrin with MTGase as wall material led to the highest encapsulation efficiency, being selected as the best microencapsulation condition; meantime, application of chitosan with maltodextrin provided the worse encapsulation efficiency (P?<?0.05). All indices of powders (encapsulation efficiency, surface morphology, and particle size) showed that powders prepared from gelatin and gelatin with MTGase increased the encapsulation efficiency and would increase the stability of microcapsule powders.     

Oxidative Stability, Structure, and Physical Characteristics of Microcapsules Formed by Spray Drying of Fish Oil with Protein and Dextrin Wall Materials

ABSTRACT: Maltodextrins and a highly branched cyclic dextrin (HBCD) were tested for their ability to serve as wall materials for microcapsules with proteins. HBCD or a maltodextrin of DE18 with sodium caseinate (SC) improved the oxidative stability of encapsulated fish oil; however, the DE18/SC wall system had 2 disadvantages: browning induced by the Maillard reaction and agglomeration. The oil load level and the selection of dextrin strongly affected the outer topography and the inner structure, as well as the ratio of the oil to dextrin on the surface of the microcapsules. It is stated that drying speeds of dextrin and oil load levels were shown to be likely related to the structural difference in the microcapsules.     

徼胶囊海藻油饮料悬浮稳定性及氧化稳定性的研究

本文主要研究斥水性微胶囊海藻油在饮料中的悬浮稳定性和氧化稳定性，实验结果表明0．25％的琼脂／瓜儿胶(1：3)复合胶能保持饮料良好的悬浮稳定性和流动性。在饮料中，与水溶性微胶囊海藻油和乳化海藻油相比，斥水性微胶囊海藻油具有较高的氧化稳定性。     

基于Vc和油脂包埋率的特医食品喷雾干燥加工工艺优化及其产品储藏稳定性分析

为探究粉剂型全营养特医食品喷雾干燥,获得粉剂型全营养特医食品喷雾干燥制粉最佳工艺,以Vc包埋率、油脂包埋率作为评价指标,利用Box-Behnken中心组合方法对喷雾干燥工艺条件进行优化,考察进风温度、进样速度、进样浓度以及风速对粉剂型全营养特医食品的影响,确定最佳喷雾干燥工艺条件,并以普通干法混合作为对照,探究不同加速试验（高温、高湿、开袋）条件下喷雾干燥法制备的全营养特医食品的储藏稳定性。研究结果表明,全营养特医食品湿法喷雾干燥加工最佳工艺条件为：进样浓度24%、进风温度132 ℃、进样速度13.5 mL/min、风速30 Hz。该工艺制备的全营养特医食品Vc包埋率和油脂包埋率为79.72%和92.25%,混合均匀度可高达99.68%。加速试验结果显示,该加工工艺较普通干法混合能够有效减缓脂肪氧化和Vc含量的损失,提高粉体的储藏稳定性。该研究结果可为提升粉剂型全营养特医食品品质提供技术支撑。     

Influence of Emulsification Technique and Wall Composition on Physicochemical Properties and Oxidative Stability of Fish Oil Microcapsules Produced by Spray Drying

Encapsulation of fish oil is an effective way to protect it against oxidation and masking its fishy odor. One of the possible ways to produce fish oil microcapsules is to produce an oil-in-water (O/W) emulsion followed by spray drying. This study compares the production of the O/W emulsion by mechanical homogenization (rotor–stator) with membrane emulsification and examines the effect of the type and amount of wall material added before drying. The membrane emulsification process selected for the emulsion production is premix membrane emulsification (ME), which consists of the production of a coarse emulsion by mechanical means followed by droplet breakup when the coarse emulsion is forced through a membrane. The emulsions produced had an oil load of 10 and 20 % and were stabilized using whey protein (isolate and hydrolyzate at 1 or 10 %) and sodium caseinate with concentrations of 2 and 10 %. Regarding the material used to build the microcapsule wall, whey protein, maltodextrin, or combinations of them were used at three different oil/wall ratios (1:1, 1:2, 1:3). The results clearly show that premix ME is a suitable technology for producing O/W emulsions stabilized with proteins, which have a smaller droplet size and are more monodisperse than those produced by rotor–stator emulsification. However, protein concentrations of 10 % are required to reduce the droplet size down to 2–3 μm. Small and monodisperse emulsions have been found to produce microcapsules with lower surface oil content, which increases oil encapsulation efficiency and presents lower levels of oxidation during storage at 30 °C. Of all the possible combinations studied, the one with the highest oil encapsulation efficiency is the production of a 20 % O/W emulsion stabilized with 10 % sodium caseinate followed by the addition of 50 % maltodextrin and drying.     

喷雾干燥法制备微胶囊鸡油脂的研究

以大豆分离蛋白和麦芽糊精为壁材,采用喷雾干燥法制备微胶囊鸡油脂并考察了其氧化稳定性.通过乳状液的稳定性质指标确定壁材大豆蛋白和麦芽糊精的比例为11.通过正交试验确定鸡油脂微胶囊化工艺条件为芯材与壁材的比例为12,乳状液的固形物浓度为20%,均质压力为25 MPa,喷雾干燥的进风温度是210℃.在最佳条件下制备微胶囊鸡油脂的包埋率为89.9%.在相同的储存条件下,制得的微胶囊鸡油脂氧化稳定性好于未包埋油脂.     

Flavor Encapsulation by Spray Drying: Application to Citral and Linalyl Acetate

Leaflash spray drying technique was used to encapsulate a mixture of two volatile products, citral and linalyl acetate in the proportion of 80:20 (w/w). The support materials were gum arabic and maltodextrin in different proportions. Very short air product contact time during the drying process allowed encapsulation of these compounds using high inlet air temperature (300-400°C) without any adverse effect on chemical properties. Emulsions were atomized up to 60% total solids concentration. In this range of concentration, substitution of gum arabic by a less costly maltodextrin was possible achieving 84% volatiles retention. The technique could be efficiently used to encapsulate sensitive flavors.     

Effect of Relative Humidity on the Oxidative Stability of Microencapsulated Sea Buckthorn Seed Oil

ABSTRACT: The effect of relative humidity (RH) (20 °C: RH 11%, 54%) on oxidative stability microencapsulated sea buckthorn seed oil was studied using bulk oil as a reference. Microcapsules were prepared by spray-drying using maltodextrin-gum arabic (MD/GA) and corn starch sodium octenyl succinate derivate (HiCap) as the wall materials. The influence of the physical state of the wall material was also evaluated. Under dry conditions, the microencapsulated oils were most stable, but the oxidation of the bulk oil was accelerated. At 20 °C and at RH 11%, the peroxide value of the bulk oil exceeded 20 meq/kg within 1 wk. Microencapsulation prolonged the shelf-life of the oil from 1 wk to 2 mo at 20 °C, when the encapsulating matrix was in glassy state. In conditions in which the HiCap matrix was in a rubbery state (RH 54%, 20 °C), the oxidation proceeded very quickly, reaching a peroxide value of 20 meq/kg just after 1 wk. Caking and collapse of the microcapsule powder were observed in the rubbery state. At accelerated conditions (50 °C: RH 11%, 30%, 45%), the oxidation was noticeably fast, not only in the bulk oil but also in the MD/GA matrix, even in the glassy state. The behavior in the HiCap matrix was more complex as the amount of peroxides started to decrease in time. This was assigned to the structural collapse in HiCap microcapsules. The behavior of the microencapsulated oils under accelerated conditions did not correlate with their behavior at 20 °C.     

喷雾干燥法制备微胶囊化杜仲籽油的研究

选用阿拉伯胶和麦芽糊精作微胶囊壁材,对喷雾干燥法制备杜仲籽油微胶囊的技术进行研究.结果表明,杜仲籽油微胶囊的优化配方为:阿拉伯胶与麦芽糊精配比1:1,心材与壁材比率2:3,乳化液浓度25%(W/V);喷雾干燥最佳工艺条件为:进风温度180 ℃,出风温度80℃,均质压力35 MPa;在此条件下,杜仲籽油微胶囊的包埋效率可稳定在84%～86%,经微胶囊化处理的杜仲籽油,氧化稳定性显著增强,微胶囊产品的颗粒外形较圆整,表面光滑,大小分布较均匀.     

Stability to Oxidation of Spray-Dried Fish Oil Powder Microencapsulated Using Milk Ingredients

ABSTRACT: Microencapsulation of fish oil was achieved by spray-drying homogenized emulsions of fish oil using 3 different types of casein as emulsifier and lactose as filler. As the degree of aggregation of the casein emulsifier increased, the vacuole volume of the microencapsulated powders decreased. The shelf life of the powders increased as the degree of aggregation of the casein emulsifier increased at the high homogenization conditions. When micellar casein was used as emulsifier, the shelf life also increased as homogenization conditions increased. Free fat but not surface fat was inversely related to shelf life. Since the type of casein used was confounded with the powder vacuole volume, the increased shelf life may have been due to either factor.     

喷雾干燥法制备芥末油微胶囊化的研究

实验以提取的芥末油为芯材,以阿拉伯胶和麦芽糊精作为壁材,经乳化、均质和喷雾干燥将芥末油树脂制成微胶囊,研究表明包埋芥末油树脂的最佳工艺条件为∶阿拉伯胶∶麦芽糊精为2∶8,芯材∶壁材为1∶3,固形物含量为35％,均质压力26MPa、进料速度15 r/min、进出口风温度235℃/90℃,包埋率可达到93.1％.