The influence of additives and drying methods on quality attributes of fish protein powder made from saithe (Pollachius virens)

BACKGROUND: Fish protein powder (FPP) is used in the food industry for developing formulated food products. This study investigates the feasibility of increasing the value of saithe (Pollachius virens) by producing a functional FPP. Quality attributes of spray and freeze‐dried saithe surimi containing lyoprotectants were studied. A freeze‐dried saithe surimi without lyoprotectants was also prepared as a control sample. RESULTS: The amount of protein, moisture, fat and carbohydrate in the FPPs were 745–928, 39–58, 21–32 and 10–151 g kg^?1. Quality attributes of FPPs were influenced by the two drying methods and lyoprotectants. The highest level of lipid oxidation was found in the control and the second highest in the spray‐dried FPP. The spray‐dried fish protein had the lowest viscosity among all FPPs. Gel‐forming ability of samples with lyoprotectants was higher than that of the control. Water‐binding capacity, emulsion properties and solubility of the freeze‐dried fish protein containing lyoprotectants were significantly higher than spray‐dried and control samples. However, functional properties of spray‐dried FPP were higher than the control sample. CONCLUSION: It is feasible to develop value‐added FPP from saithe surimi using spray‐ and freeze‐drying processes, but freeze‐dried FPP containing lyoprotectant had superior functional properties and stability compared with spray‐dried sample. Both products might be used as functional protein ingredients in various food systems. Copyright © 2010 Society of Chemical Industry     

The loss of OSA‐modified starch emulsifier property during the high‐pressure homogeniser and encapsulation of multi‐flavour bergamot oil by spray drying

The encapsulation of bergamot oil by spray drying was investigated by using octenyl succinylated waxy maize starch as wall material and bergamot oil as core. The bergamot oil is majorly composed of d‐limonene, linalool and linalyl acetate. High‐speed and high‐pressure homogenisers were used as major tools of emulsification process. The results indicated that some chemical functional groups were lost during the high‐pressure homogenisation. Moreover, larger emulsion droplet size (5–10 μm) was observed when emulsion passed through high‐pressure homogeniser. Meanwhile, the saturation of carrier solution before preparing the emulsion was also important to produce the encapsulated flavour powder by spray drying. The optimal value of air inlet temperature at 160 °C to give the highest flavour retention and the lowest surface oil content was observed. Furthermore, the retention of linalool after spray drying was higher than 100%. The transformation of each flavour might occur.     

Optimising emulsion stability during processing of model infant formulae using factorial statistical design

This study examined the effects of total solids (TS), preheat treatment temperature, and first‐ and second‐stage homogenisation pressures on the stability of model infant formula emulsions, using factorial statistical design. Oil droplet size decreased with increasing first‐ and second‐stage homogenisation pressures. The viscosity of emulsions after homogenisation was mainly affected by TS. Spray drying altered the protein profile of the interfacial layer around oil droplets compared to that posthomogenisation, but did not alter oil droplet size. This work made it possible to select optimum conditions to produce a stable infant formula emulsion, with the use of lower homogenisation pressures.     

Spray drying behaviour and functionality of emulsions with β-lactoglobulin/pectin interfacial complexes

Aim of the present study was to investigate the impact of atomization and drying on the functionality of emulsions with a bilayered oil–water interface consisting of a globular protein (β-lactoglobulin, bLG) and anionic polysaccharides (pectins with varying degree of methoxylation). With regard to the atomization process, the emulsion spray droplet size generally decreased with increasing atomization energy. The spray droplet size distribution was narrower with rotary atomization compared to two-fluid nozzle atomization. The single droplet drying behaviour of the differently stabilized emulsions was similar as examined by acoustic levitation. With more than 95%, microencapsulation efficiency was high in all spray-dried particles. However, a shift in oil droplet size upon reconstitution indicated that oil droplet coalescence occurred within the process which was less pronounced in bilayer emulsions compared to the bLG-stabilised single layer emulsion. Data from interfacial viscoelasticity measurements showed distinct differences, which may explain oil droplet coalescence. The oxidative stability of encapsulated oil was influenced by both the physical state of the emulsions and the different constituents at the o/w-interface with bLG and low methoxylated pectin giving the best protection of the oil.     

干燥方式对不同接枝度的大豆分离蛋白-麦芽糊精聚合物性质影响

以大豆分离蛋白(SPI)和麦芽糊精(MD)为原料制备不同接枝度的SPI-MD聚合物,研究比较喷雾干燥和冷冻干燥两种处理方式对不同接枝度下的SPI-MD聚合物性质的影响,如溶解度、疏水性、持水性、乳化性、乳化稳定性及起泡性、泡沫稳定性等的影响。实验表明,喷雾干燥样品的溶解性,表面疏水性和乳化性高于冷冻干燥样品;冷冻干燥样品则具有较好的持水性。另外,两种干燥样品的乳化稳定性非常接近。不同接枝度的两种干燥样品起泡性差异较大,且泡沫稳定性都相对较差。     

Lipid Encapsulation in Glassy Matrices of Sugar-Gelatin Systems in Freeze-Drying

Entrapment of lipid in glass forming matrices in freeze-drying was investigated. Dispersion of lipid in aqueous solutions of three different sugars was formed by addition of protein and using homogenisation process. Two different levels of proteins in the ratios of 9:1 and 8:2 (sugar:protein) were used. Three different homogenisation processes were used to vary the emulsion droplet size of dispersed lipid. A novel ultra high-pressure homogenisation treatment with pressure levels up to 255 MPa (5MPa in second stage) was used to form emulsion before freeze-drying. The non-fat solids formed a glass in freezing which led to entrapment of dispersed oil. Ultra high-pressure homogenisation at pressure levels higher than 155 MPa caused alterations in emulsifying properties of sugar/gelatin systems. Changes in emulsifying properties of encapsulation matrices affected entrapment of dispersed lipid components. Droplet size of the dispersed phase was a significant factor for encapsulation efficiency. Emulsions with smaller droplet diameter gave higher entrapped amounts of lipid than emulsions with larger droplets. The glass forming properties and physical state of freeze-dried matrices were also determined. Knowledge of glass forming properties of an encapsulation matrix is needed for entrapment and predicting the stability and release properties of entrapped components.     

Effect of high‐pressure homogenisation on the retention of selected aroma compounds in model dairy emulsions

The aim of this work was to investigate the effects of high‐pressure homogenisation on the aroma retention of mixed sodium caseinate–whey protein (2% + 2% w/v) emulsions. For this purpose, raw and pasteurised emulsions, with different fat contents (5%, 8% and 15% w/v) and subjected to different homogenisation pressures (0, 18, 100 and 150 MPa), were produced. The retention of seven aroma compounds (hexanal, benzaldehyde, diacetyl, ethyl butyrate, isoamyl acetate, ethyl hexanoate and ethyl octanoate) was evaluated by static headspace gas chromatography. Results showed that aroma release was affected by the presence and the quantity of the lipid phase. As regards homogenisation, an increase in the retention of hexanal with homogenisation pressure was observed and interactions between hexanal and caseinate were suggested. Benzaldehyde showed significant changes in headspace partition with increasing pressure only in the 5% fat content emulsions, whereas no homogenisation effect on aroma retention was observed for diacetyl or esters.     

热处理对大豆分离蛋白稳定乳液包埋特性的影响

本实验通过喷雾干燥前对SPI溶液95℃1 5 min热处理及形成乳液后加入乳糖溶液制备粉末样品,并将部分干粉储存于RH 75%环境中记录其7 d内等温吸湿线,待吸湿稳定后得到湿粉样品,测定原始乳液及干、湿粉末复溶乳液的粒径大小分布,干、湿粉末的水分含量、包埋效率(ME)、溶解速率并用扫描电镜(SEM)观察其微观结构。结果表明热处理和加糖处理能显著提高喷雾干燥SPI稳定乳液的包埋效率,高达98.68%,相对于未经处理的SPI乳液包埋效率高出1倍以上,此外含糖粉末表现出良好的溶解性,但潮湿环境对其溶解性、包埋效率及微观结构有较大影响。     

The effects of high-pressure homogenization,drying pH and propylene glycol on the emulsifying properties of pea protein powder

Pea protein is a promising option for plant protein-based emulsification, but commercial proteins have limited functional properties related to their poor physicochemical properties such as solubility. To address this issue, this research investigated the effects of high-pressure homogenisation and extraction conditions on the solubility and emulsification properties of pea protein. Heating during extraction can denature pea protein and simulate the reduced functional properties of commercial proteins. Homogenising at 10 000 psi combined with the heating process during extraction significantly improved the solubility and emulsification properties of pea protein. Freeze drying at pH 9.0 improved the solubility of pea protein and lowered the droplet size of resultant emulsions compared to pH 7.0. Extracting the protein in propylene glycol to inhibit hydrophobic interactions slightly improved solubility but decreased the emulsification properties. The combination of homogenisation during heating and freeze drying at an elevated pH produced the optimum solubility and emulsification properties. These results suggest that high-pressure homogenisation and drying at elevated pH levels can be effective tools to limit the functionality-reducing effects of denaturation that occurs during the commercial extraction of pea protein. This information can be used to design better production methods for pea protein and improve its functional properties.     

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.     

Pea (<Emphasis Type="Italic">Pisum sativum,L.</Emphasis>) Protein Isolate Stabilized Emulsions: A Novel System for Microencapsulation of Lipophilic Ingredients by Spray Drying

Oil-in-water emulsions can be considered as an important delivery system for lipophilic food molecules. In this study, pea protein isolate (PPI) was studied for its emulsifying capacity at various pH values and pH 7 was selected to prepare emulsions for the production of dry microcapsules. Emulsions stabilized by PPI just enough to cover oil droplets were mixed with solutions of starch hydrolysates of various dextrose equivalent (DE) and subsequently spray dried to yield powders with 30 wt% oil. Effects of DE (6, 12, 19, and 28) on feed emulsion properties and on the characteristics of the spray-dried powders were examined. Reconstituted emulsion oil droplet size and stability were affected by DE in all cases. Microencapsulation efficiency of dried emulsions increased significantly with increasing DE. The scanning electron microscope results showed that lower maltodextrins DE microcapsules are shallow and presented rough surfaces or invaginations. However, higher carbohydrates DE microcapsules were circular and uniform showing minimum cracks and dents on the surface confirming these DE to be efficient encapsulating materials. The formation of the drying matrix seems control the destabilization of pea protein-coated oil droplets during spray drying. In systems where the matrix is formed in a uniform manner, the interfacial protein film is less affected by the drying process. Thus the functionalities of pea protein can be protected during drying by using high DE carbohydrates.     

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.     

Behaviour of oil droplets during spray drying of milk-protein-stabilised oil-in-water emulsions

The effects of spray drying on the behaviour of oil droplets in oil-in-water emulsions (12.0%, w/w, maltodextrin; 20.0%, w/w, soya oil) stabilised with either sodium caseinate or whey protein isolate (WPI) were examined as a function of protein concentration (0.5–5.0%, w/w). Spray drying and redispersion caused a shift in the droplet size distribution to larger values for all emulsions made using low protein concentrations (0.5–2.0%, w/w), in comparison with their respective parent emulsions. However, the droplet size distribution was affected only very slightly by spray drying when the protein concentration was above 2.0% (w/w). The effects of maltodextrin concentration (1.0–25.0%, w/w) on the behaviour of WPI-stabilised emulsions (0.5–10.0%, w/w, WPI, 20.0%, w/w, soya oil) were also examined. Emulsions containing low levels of maltodextrin showed marked re-coalescence during spray drying and redispersion even at a WPI concentration of 10.0% (w/w).     

Microencapsulation properties of two different types of n-octenylsuccinate-derivatised starch

Aim of the present study was to evaluate the suitability of two different types of n-octenylsuccinate-derivatised starch, which significantly differed in viscosity, for microencapsulation of a fish oil rich in long-chain polyunsaturated fatty acids. Stable feed emulsions for microencapsulation could be prepared with both types of n--octenylsuccinate starch, however at a high oil load (50%), a low pH (pH 4.5) of the emulsion was crucial for emulsion stability. At 50% oil content, lower oil droplet size in reconstituted spray-dried emulsions and lower content of non-encapsulated oil was reached by low viscosity starch compared to medium viscosity starch. Conjugated dienes were significantly increased in samples with a high oil load and 40% starch indicating that to a certain degree lipid oxidation already occurred in these samples during the drying process. Finally, moderate spray-drying conditions must be considered as advantageous, since ballooning of the particles and lipid oxidation during spray drying were limited compared to drying at high spray-drying temperatures.     

干燥方式对秋葵超微粉理化特性及抗氧化活性的影响

以热风、真空冷冻两种干燥方式对4 个品种（爱木1号（爱1）、老蓝、孟1、爱木5号（爱5））的秋葵果 实进行干燥并将其超微粉碎,研究干燥方式对秋葵超微粉的理化特性及其抗氧化活性的影响。结果表明：热风干 燥与真空冷冻干燥的秋葵超微粉在物理特性（溶解性、持水力、容重）、VC含量、叶绿素含量和抗氧化活性方面 都存在显著差异（P＜0.05）。与热风干燥相比,真空冷冻干燥的秋葵超微粉溶解性大,持水力、容重小,VC含量 高,且其甲醇提取液对1,1-二苯基-2-三硝基苯肼和O2 － ·的清除能力较强。真空冷冻干燥后,4 个品种的秋葵超微粉 除持水力和容重外,其他指标存在显著差异（P＜0.05）;其中,孟1超微粉的溶解度最高,VC含量丰富,抗氧化 活性最强。本研究结果认为真空冷冻干燥的秋葵超微粉在物理特性方面优于热风干燥的,且具有较高的VC含量和 抗氧化活性,说明该干燥方式更适用于秋葵超微粉的生产,尤其是采用真空冷冻干燥方式加工孟1品种的秋葵更具 有市场价值。     

Physicochemical properties and storage stability of spray‐dried soya bean sprout extract

Amylase is a very important enzyme due to its wide food applications. To preserve amylase activity in soya bean sprout extract (SSE), SSEs were spray‐dried with 10% maltodextrin and 0–3% alginic acids, and their physicochemical properties and storage stability were compared with freeze‐dried one. SSE exhibited maximum amylase activity at pH 7.0 and 60 °C, with the most active substrate specificity towards soluble starch. Spray‐dried SSEs exhibited higher water solubility index (WSI) and in vitro relative amylase activity but lower water vapour sorption (WVS) and smaller particle size than freeze‐dried SSE. For spray‐dried SSEs, particle size, WSI and in vitro relative amylase activity increased while WVS decreased with increasing % alginic acid. This study demonstrated that spray drying of SSE, especially with 10% maltodextrin and 2% alginic acid, was effective in keeping amylase active and stable during 7‐week storage at room temperature (25 °C).     

Particle size distribution and homogenisation efficiency in high-pressure homogenisation of wheat germ oil-water system

Wheat germ oil (WGO) is well-known as a good source of vegetable oil due to its nutrients and health benefits. Emulsification is a process that improves the incorporation of oil into food. High-pressure homogenisation (HPH) is a nonthermal and soft technique with enormous potential in oil-in-water emulsification. This paper focussed on the application of HPH for emulsification of WGO-in-water system. Influences of homogenisation pressure (100–300 bar), oil fraction (10–20% v/v) and lecithin adding (0–0.2% w/v of content) on the homogenisation were evaluated based on distribution of particles diameter and homogenisation efficiency. The increase in operating pressure and lecithin ratio decreased the particle size and increased the emulsion stability, and vice versa for oil fraction. The findings imply that the investigated factors significantly influenced particle size and emulsion system stability. The regression model between mean particle diameter and technical conditions of emulsion was established. With HPH treatment conditions of 300 bar operating pressure, 10% (v/v) oil fraction and 0.2% (w/v) lecithin created an emulsion system with a mean particle size of 3.32 µm, more than 50% of the volume of particles smaller than 1.5 µm of diameter and the homogenisation efficiency of 98.61%. HPH exhibits high efficiency and potential in WGO-in-water emulsification application.     

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.     

喷雾干燥与冷冻干燥玉米肽工艺的比较研究

以酶解法制备的玉米肽为原料,对其冷冻干燥和喷雾干燥的工艺进行研究。确定冷冻干燥条件为预冷温度－30℃,预冷时间2h;加热温度从－10℃开始18h后缓慢升温,达到25℃,并保持到干燥终点。喷雾干燥的最佳工艺参数为进风温度180℃,进样速度为30ml/min,离心雾化器转速为20000r/min。并对两种干燥方法制得产品的理化特性进行了比较。     

Effect of oil content and processing conditions on the thermal behaviour and physicochemical stability of oil-in-water emulsions

The destabilisation mechanism of oil-in-water (o/w) emulsions was studied as a function of oil content (20% and 40% o/w), homogenisation conditions and crystallisation temperatures (10, 5, 0, −5 and −10 °C). A mixture of anhydrous milk fat and soya bean oil was used as the lipid phase and whey protein isolate (2 wt%) as emulsifier. Crystallisation and melting behaviours were analysed using differential scanning calorimetry. Physicochemical stability was measured with a vertical scan macroscopic analyser. Emulsions with 20% oil were found to be less stable than those with 40% oil. For 20% o/w emulsions, the crystallisation was delayed and inhibited in emulsions with smaller droplets and promoted in emulsions with larger droplets when compared with 40% o/w emulsions. Depending on the droplet sizes in the emulsion, the formation of lipid crystals (in combination with the emulsifier) either stabilises (small droplets) or destabilises (big droplets) the emulsion.