Effect of gum arabic concentration and inlet temperature during spray drying on physical and antioxidant properties of honey powder

The research studied the effect of gum arabic concentration at 35, 40 and 45 % with inlet temperatures of 160, 170 and 180 °C on the physico-chemical, functional and thermal properties of honey powder enriched with aonla (Emblica officinalis. Gaertn) and basil (Ocimum sanctum) extract, wherein other parameters like concentration of aonla extract (8 %), basil extract (6 %) and feed rate (0.11 mL/s) were kept as constant. Powder recovery and glass transition temperature (T_g) showed significant increase with the increase in inlet temperatures. On the other hand hygroscopicity, tapped density, total phenolic content, antioxidant activity and vitamin C content showed inverse response to the increase in inlet temperatures. However powder recovery, T_g, total phenolic content, antioxidant activity and vitamin C content increased with the increase in concentration of gum arabic. On the basis of obtained results it can be concluded that honey powder with the concentration of 45 % gum arabic at 170 °C inlet temperature was found to be less hygroscopic with better powder recovery and overwhelming antioxidant properties.     

Degradation kinetics of ascorbic acid in encapsulated spray-dried honey powder packaged in aluminium laminated polyethylene and high-density polyethylene

The present study evaluated the stability of nutritionally rich encapsulated spray-dried honey powders in terms of hygroscopicity, glass transition temperature, total phenolic content, antioxidant activity and ascorbic acid using maltodextrin, gum arabic, and whey protein concentrate as carriers during a storage period of 180 days using high-density polyethylene and aluminium laminated polyethylene as packaging materials at 25°C (room temperature) and 35°C (accelerated temperature). The results revealed that temperature caused a negative influence on the glass transition temperature and stability of ascorbic acid. The kinetics of ascorbic acid degradation followed a first-order reaction with a reaction rate constant dependent on temperature and packaging material. Honey powder developed with whey protein concentrate as carrier agent and stored in aluminium laminated polyethylene pouches at 35°C possessed the highest antioxidant activity and ascorbic acid due to the presence of phenolic compounds in honey, aonla (Emblica officinalis. Gaertn), and basil (Ocimum sanctum) extract. The honey powders stored in aluminium laminated polyethylene pouches showed comparatively better antioxidant properties (total phenolic content, ascorbic acid, and antioxidant activity) and minimum hygroscopicity than the powders stored in high-density polyethylene at both the storage temperatures.     

Effect of carrier types and compositions on the production yield,microstructure and physical characteristics of spray dried sour cherry juice concentrate

In this study, the effect of different carriers including maltodextrin (MD), gum arabic (GA) and whey protein concentrate (WPC) and their combination on the production yield, moisture content, bulk and tapped density, solubility, wettability, flowability indexes (Hausner ratio, compressibility, angle of repose), hygroscopicity and deliquescence process, color index and microstructure of spray dried sour cherry juice concentrate was investigated. The results showed increased powder production yield with a mixture of MD and GA (40:10 weight ratio). Use of 5% WPC in combination with the GA and MD increased powder production yield from 45.66 to 55.66% and 42.23 to 52.86%, respectively. Bulk density, tapped density, solubility and wettability significantly decreased with increasing concentration of WPC. Also, the use of 30% WPC in combination with the MD or GA increased particle size substantially. The surface morphology of the particles (with a smooth, shrunk and dented surfaces) was affected by feed composition.     

The Effect of Feed Solids Concentration and Inlet Temperature on the Flavor of Spray Dried Whey Protein Concentrate

Previous research has demonstrated that unit operations in whey protein manufacture promote off‐flavor production in whey protein. The objective of this study was to determine the effects of feed solids concentration in liquid retentate and spray drier inlet temperature on the flavor of dried whey protein concentrate (WPC). Cheddar cheese whey was manufactured, fat‐separated, pasteurized, bleached (250 ppm hydrogen peroxide), and ultrafiltered (UF) to obtain WPC80 retentate (25% solids, wt/wt). The liquid retentate was then diluted with deionized water to the following solids concentrations: 25%, 18%, and 10%. Each of the treatments was then spray dried at the following temperatures: 180 °C, 200 °C, and 220 °C. The experiment was replicated 3 times. Flavor of the WPC80 was evaluated by sensory and instrumental analyses. Particle size and surface free fat were also analyzed. Both main effects (solids concentration and inlet temperature) and interactions were investigated. WPC80 spray dried at 10% feed solids concentration had increased surface free fat, increased intensities of overall aroma, cabbage and cardboard flavors and increased concentrations of pentanal, hexanal, heptanal, decanal, (E)2‐decenal, DMTS, DMDS, and 2,4‐decadienal (P < 0.05) compared to WPC80 spray dried at 25% feed solids. Product spray dried at lower inlet temperature also had increased surface free fat and increased intensity of cardboard flavor and increased concentrations of pentanal, (Z)4‐heptenal, nonanal, decanal, 2,4‐nonadienal, 2,4‐decadienal, and 2‐ and 3‐methyl butanal (P < 0.05) compared to product spray dried at higher inlet temperature. Particle size was higher for powders from increased feed solids concentration and increased inlet temperature (P < 0.05). An increase in feed solids concentration in the liquid retentate and inlet temperature within the parameters evaluated decreased off‐flavor intensity in the resulting WPC80.     

Characterisation of heat-set milk protein gels

Milk protein solutions [10% protein, 40/60 whey protein/casein ratio containing whey protein concentrate (WPC) and low-heat or high-heat milk protein concentrate (MPC)] containing fat (4% or 14%) and 70–80% water, form gels with interesting textural and functional properties if heated at high temperatures (90 °C, 15 min; 110 °C, 20 min) without stirring. Adjustment of pH before heating (HCl or glucono-δ-lactone) produces soft, spoonable gels at pH 6.25–6.6, but very firm, cuttable gels at pH 5.25–6.0. Gels made with low-heat MPC, WPC and low fat gave some syneresis; high-fat gels were slightly firmer than low-fat gels. Citrate markedly reduced gel firmness; adding calcium had little effect on firmness, but increased syneresis of low-heat MPC/WPC gels. The gels showed resistance to melting, and could be boiled or fried without flowing. Microstructural analysis indicated a network structure of casein micelles and fat globules interlinked by denatured whey proteins.     

Effect of spray drying and freeze drying on the immunomodulatory activity,bitter taste and hygroscopicity of hydrolysate derived from whey protein concentrate

The main aim of the present work was to obtain microencapsulated whey protein concentrate hydrolysate (WPCH) in order to reduce its bitter taste and resistance to hygroscopicity without impairing its immunoregulatory activity by spray drying or freeze drying with whey protein concentrate (WPC) and sodium alginate (SA) as carriers. To attenuate its bitter taste, the WPCH were encapsulated with WPC or the mixture of WPC and sodium alginate (WPC/SA). The splenocyte proliferation activity, hygroscopicity, bitter taste and morphology of non-encapsulated WPCH and encapsulated WPCH were evaluated. Results revealed that WPCH could significantly enhance splenocyte proliferation activity compared with WPC itself. Both spray drying and freeze drying with or without carrier material addition did not exert negative effect on the immunomodulatory activity of WPCH. The bitterness, determined by taste dilution analysis method, of both WPC-encapsulated WPCH and WPC/SA-encapsulated WPCH was significantly lower than that of the original non-encapsulated WPCH. Morphological analysis showed that freeze drying process could not encapsule WPCH as spray drying did. All of these indicated that spray drying with WPC or the mixture of WPC and SA (WPC/SA) as carriers was beneficial for reducing the bitter taste and hygroscopicity without impairing the immunoregulatory activity of whey protein hydrolysate.     

Optimum aqueous extraction conditions for preparation of a phenolic‐enriched Davidson's plum (Davidsonia pruriens F. Muell) extract

This study aimed to optimise aqueous extraction conditions for total phenolic compounds (TPC) from Davidson's plum (Davidsonia pruriens F. Muell) and to assess the physicochemical and antioxidant properties of the phenolic‐enriched extract. The results showed that temperature, time and ratio significantly affected the extraction of TPC. Optimization of extraction conditions was performed using response surface methodology (RSM) utilising a Box–Behnken design. Optimal extraction conditions were determined to be temperature: 90 °C, extraction time: 30 min and solvent to mass ratio: 20:1 mL g^?1. The extracted solid obtained under these conditions had low‐moisture content, high water solubility and contained 45 mg GAE g^?1 of TPC, 22 mg RUE g^?1 of flavonoids, 3.2 mg CAE g^?1 of proanthocyanidins, 2 mg CGE g^?1 of anthocyanidins and 56 mg ACE g^?1 vitamin C. The extract possessed potent antioxidant capacity, but was comparatively lower than those of vitamin E and BHT. Thus, Davidson's plum should be further investigated for its potential health promoting benefits and utilisation in the nutraceutical and food industries.     

Co‐extrusion of pearl millet‐whey protein concentrate for expanded snacks

A study was conducted to develop pearl millet‐based extruded snacks with whey protein concentrate (WPC) to enhance its acceptability and nutritional value. Pearl millet grits (841 μ) was extruded with different levels (0%, 2.5%, 5.0% and 7.5%) of WPC at constant feed rate (10.5 kg h^?1) and moisture content (14%). Addition of whey protein at 7.5% level significantly (P ≤ 0.05) increased T_g from 75.1 ± 0.26 °C to 120.5 ± 1.28 °C and T_m from 89.1 ± 1.51 °C to 158.7 ± 1.37 °C, which resulted in less expanded and harder extrudates. The expansion index of extrudates was negatively correlated (P ≤ 0.05) with protein (r = ?0.940), bulk density (r = ?0.949), hardness (r = ?0.971) and breaking strength (r = ?0.921), while positively correlated (P ≤ 0.05) with overall acceptability (OAA; r = 0.988). Keeping in view the nutritional, textural and consumer's acceptability, incorporation of 5% WPC in pearl millet grits (841 μ) was recommended for preparation of acceptable expanded snacks.     

Optimisation of spray drying process parameters for low‐fat honey‐based milk powder with antioxidant activity

The purpose of this study was to optimise process parameters to prepare spray‐dried honey‐based milk powder containing functional properties of honey. Experimental design with temperature (180 to 200 °C), honey concentration (5–15%) and feed flow rate (8–10 rpm) as independent variables was studied to investigate the effect on product responses. Results showed that increasing the temperature resulted in powder with lower moisture, bulk density, antioxidant activity, total phenolic contents, total flavonoid contents and higher water solubility index. Increasing feed flow rate resulted in higher moisture, bulk density, antioxidant activity, reduced water solubility index, total phenolic content and total flavonoid content, whereas increasing honey concentration resulted in increase in antioxidant activity, total phenolic content and total flavonoid content. The moisture content, bulk density, water solubility index, DPPH scavenging activity, total phenolic content and total flavonoid content were 3.27%, 0.44 g cc^?1, 96.67 g g^?1, 17.45%, 2.54 GAE g^?1 powder and 1.40 RE g^?1 powder, respectively.     

The effect of bleaching agents on the degradation of vitamins and carotenoids in spray-dried whey protein concentrate

Previous research has shown that bleaching affects flavor and functionality of whey proteins. The role of different bleaching agents on vitamin and carotenoid degradation is unknown. The objective of this study was to determine the effects of bleaching whey with traditional annatto (norbixin) by hydrogen peroxide (HP), benzoyl peroxide (BP), or native lactoperoxidase (LP) on vitamin and carotenoid degradation in spray-dried whey protein concentrate 80% protein (WPC80). An alternative colorant was also evaluated. Cheddar whey colored with annatto (15 mL/454 L of milk) was manufactured, pasteurized, and fat separated and then assigned to bleaching treatments of 250 mg/kg HP, 50 mg/kg BP, or 20 mg/kg HP (LP system) at 50°C for 1 h. In addition to a control (whey with norbixin, whey from cheese milk with an alternative colorant (AltC) was evaluated. The control and AltC wheys were also heated to 50°C for 1 h. Wheys were concentrated to 80% protein by ultrafiltration and spray dried. The experiment was replicated in triplicate. Samples were taken after initial milk pasteurization, initial whey formation, after fat separation, after whey pasteurization, after bleaching, and after spray drying for vitamin and carotenoid analyses. Concentrations of retinol, a-tocopherol, water-soluble vitamins, norbixin, and other carotenoids were determined by HPLC, and volatile compounds were measured by gas chromatography-mass spectrometry. Sensory attributes of the rehydrated WPC80 were documented by a trained panel. After chemical or enzymatic bleaching, WPC80 displayed 7.0 to 33.3% reductions in retinol, β-carotene, ascorbic acid, thiamin, α-carotene, and α-tocopherol. The WPC80 bleached with BP contained significantly less of these compounds than the HP- or LP-bleached WPC80. Riboflavin, pantothenic acid, pyridoxine, nicotinic acid, and cobalamin concentrations in fluid whey were not affected by bleaching. Fat-soluble vitamins were reduced in all wheys by more than 90% following curd formation and fat separation. With the exception of cobalamin and ascorbic acid, water-soluble vitamins were reduced by less than 20% throughout processing. Norbixin destruction, volatile compound, and sensory results were consistent with previous studies on bleached WPC80. The WPC80 colored with AltC had a similar sensory profile, volatile compound profile, and vitamin concentration as the control WPC80.     

Composition and Properties of Spherosil-QMA Whey Protein Concentrate

The Spherosil-QMA ion exchange process was used to prepare whey protein concentrate (WPC) from cheese whey. The process recovered about 64% of the proteins from whey as a 63% protein WPC. The WPC contained about 20.8% lactose, glucose, and galactose. The WPC proteins ranged in solubility from about 32–42% as a function of pH 3–7 and appeared to have undergone substantial denaturation by HPLC but not by palyacrylamide gel electrophoresis. The gelation properties of WPC were compared with those of commercial and ultrafiltration WPCs as a function of pH 3–7.5 and 0.0–0.15M NaCl and CaCl₂. The WPC did not function well as egg replacer in model cake and custard formulations.     

Production of whey protein nanofiber as a carrier for copper entrapment

Novel electrospun fibers from aqueous whey protein solution with and without a carrier polymer have been developed and characterized, exploring the ability of those fibers to carry nutrients that are considered attractive. In this study, whey protein concentrate (WPC) solution electrospun into nanofibers in conjunction with (1% w/w in solution) and without a spinnable polymer, polyethylene oxide (PEO), for carrying copper. The electrospun fibers were successfully produced from WPC/copper and a PEO/WPC/copper polymer solution under the applied voltage of 15–23 kV, when the copper concentration was relatively low. The applied voltage has no significant effect on the size of the fibers produced by WPC/copper and PEO/WPC/copper polymer systems (p > 0.05). The copper concentration in WPC/copper and the PEO/WPC/copper polymer solution significantly affect the viscosity of the solution and the size of the fiber (p < 0.05), but it has no observable change on the morphology of the fiber. The addition of PEO in the polymer solution slightly increases the solution viscosity, but the fiber of the polymer solution with PEO was 100–400times smaller than that without PEO. Micron fibers prepared by WPC polymer solution and nanofibers prepared by PEO/WPC polymer solution successfully carried copper.     

Spray Drying of Roselle (Hibiscus sabdariffa L.) Extract

Hibiscus sabdariffa (Roselle) powder was produced by pilot scale spray drying using single strength and vacuum concentrated water extract of its calyces. Powders were analyzed for moisture, protein, vitamin C, total soluble solids (TSS), pH, particle size, bulk density, solubility, dispersibility, hygroscopicity, and microbiological status. The lowest inlet air temperature (198.5°C) resulted in the product with best protein content (12.43%), retention of vitamin C (82.76 mg/ 100g), and solubility (dissolving in 97 sec); as well as the highest moisture content (3.78%) in the product. The powder showed a noticeable tendency to stick to internal surfaces of the drying chamber particularly with concentrated solutions at higher temperatures.     

Gelation of Calcium-Reduced and Lipid-Reduced Whey Protein Concentrates as Affected by Total and Ionic Mineral Concentrations

Rheological and microstructural properties of five dialyzed whey protein concentrate (WPC) gels were investigated. Maximum WPC gel hardness as determined by shear stress (ST) was observed at 2.7–4.5 mM Ca and 0.6–1.1 mM Ca²⁺ concentrations with a Ca ionization of 20–25%. Gel cohesiveness by shear strain (SN) correlated with total lipid and phospholipid (PLP) concentrations and percent of lipid unsaturation. Microstructural characteristics of the gels, as determined by light microscopy (LM), confirmed their water holding capacity (WHC) and rheological properties.     

A process for turning pomegranate peels into a valuable food ingredient using ultrasound-assisted extraction and encapsulation

A new method for pomegranate peel application in food industries was developed based on the ultrasound-assisted extraction of phenolic compounds and their subsequent encapsulation by spray drying. The effects of various parameters on extraction yield, on encapsulation efficiency/yield, and on the main physical properties of the microcapsules (moisture content, bulk density, rehydration ability) were studied. Ultrasound was found to increase extraction yield, but mainly to shorten the treatment time by over 20 times. The maximum encapsulation efficiency was 99.80% and the optimum operating conditions were found to be: wall material, maltodextrin/whey protein isolate (50:50); inlet air temperature, 150 °C; drying air flow rate, 17.5 m³/h; ratio of wall to core material, 9/1; feed solid concentration, 30% (w/w). The encapsulated phenolic extract was found efficient in improving the shelf life of hazelnut paste, in spite of the limited solubility of the crude extract in such a high lipid content matrix.Industrial relevancePomegranate peels, a by-product of pomegranate juice and concentrate industries, present a wide range of pharmaceutical and nutraceutical properties. Therefore, the peels could have more beneficial applications in food industries instead of being used as animal feed or in commercial cosmetic products. In this work, a new method for pomegranate peel application was developed based on the ultrasound-assisted extraction of phenolics and their subsequent encapsulation by spray drying.     

Mechanical properties of protein‐stabilized starch‐based supercritical fluid extrudates

Mechanical properties of starch‐based supercritical fluid extrusion (SCFX) extrudates were correlated to their structure. Thermosetting ingredients were added to the feed and the extrudate was dried to set the expanded structure. Compared to whey protein concentrate with 34% protein (WPC‐34), addition of egg white (EW) gave a softer skin and a fragile but well formed cellular structure. For drying between 70 and 100 °C, the overall structure was more homogenous for EW added. A higher modulus was associated with a larger number average of sides in a cell face and higher percentage of closed cells. Ashby's model (1983) for non‐food cellular solids gave a good fit to our data for relating relative compressive modulus to relative bulk density. A linear regression model indicated that bulk density alone was a good predictor of mechanical strength.     

Prebiotic fibre‐incorporated whey protein crisps processed by supercritical fluid extrusion

Prebiotic soluble fibre (fructooligosaccharides)‐incorporated whey protein crisps were produced by low‐shear supercritical fluid extrusion (SCFX), which utilises supercritical CO₂ as an expansion agent instead of steam. Protein crisps with desirable qualities were obtained with a formulation containing 8% prebiotic fibre and 60% whey protein concentrate (WPC‐80), which gave the final product with a protein content of 49.6% (w/w). A maximum of 70% WPC‐80 and 8% prebiotic fibre could be incorporated to produce expanded protein crisps; however, increasing WPC‐80 from 50% to 70% decreased the end‐product expansion ratio from 3.1 to 1.2 and increased the product hardness and piece density from 1.3 to 2.8 kN and 0.63 to 0.75 g mL^?1, respectively. Addition of 8% prebiotic fibre did not affect the textural qualities of final products. The process produced an expanded protein matrix with unique internal microstructure of uniformly distributed closed cells. Amino acid analysis indicated that 90% of the total lysine and 92% of the total essential amino acids were retained after SCFX processing and oven‐drying, indicating the preservation of protein nutritional quality during the process.     

Influence of storage, heat treatment, and solids composition on the bleaching of whey with hydrogen peroxide

The residual annatto colorant in liquid whey is bleached to provide a desired neutral color in dried whey ingredients. This study evaluated the influence of starter culture, whey solids and composition, and spray drying on bleaching efficacy. Cheddar cheese whey with annatto was manufactured with starter culture or by addition of lactic acid and rennet. Pasteurized fat-separated whey was ultrafiltered (retentate) and spray dried to 34% whey protein concentrate (WPC34). Aliquots were bleached at 60 °C for 1 h (hydrogen peroxide, 250 ppm), before pasteurization, after pasteurization, after storage at 3 °C and after freezing at -20 °C. Aliquots of retentate were bleached analogously immediately and after storage at 3 or -20 °C. Freshly spray dried WPC34 was rehydrated to 9% (w/w) solids and bleached. In a final experiment, pasteurized fat-separated whey was ultrafiltered and spray dried to WPC34 and WPC80. The WPC34 and WPC80 retentates were diluted to 7 or 9% solids (w/w) and bleached at 50 °C for 1 h. Freshly spray-dried WPC34 and WPC80 were rehydrated to 9 or 12% solids and bleached. Bleaching efficacy was measured by extraction and quantification of norbixin. Each experiment was replicated 3 times. Starter culture, fat separation, or pasteurization did not impact bleaching efficacy (P > 0.05) while cold or frozen storage decreased bleaching efficacy (P < 0.05). Bleaching efficacy of 80% (w/w) protein liquid retentate was higher than liquid whey or 34% (w/w) protein liquid retentate (P < 0.05). Processing steps, particularly holding times and solids composition, influence bleaching efficacy of whey. PRACTICAL APPLICATION: Optimization of whey bleaching conditions is important to reduce the negative effects of bleaching on the flavor of dried whey ingredients. This study established that liquid storage and whey composition are critical processing points that influence bleaching efficacy.     

Impacts of glucosamine/oligochitosan glycation and cross‐linking by transglutaminase on the structure and in vitro antigenicity of whey proteins

With the fixed and selected conditions, whey protein concentrate (WPC) was glucosamine‐/oligochitosan‐glycated and cross‐linked by transglutaminase, resulting in glucosamine conjugation of 4.18–5.88 g/kg. Electrophoretic analysis showed cross‐linking and glycation of whey proteins, while circular dichroism analysis indicated that the two reactions contributed less ordered secondary structure to the two products. Enzyme‐linked immunosorbent assay results showed that the two products lost 64–95% antigenic responses of WPC, and oligochitosan was more powerful than glucosamine to reduce the responses. Rocket immuno‐electrophoretic analysis also evidenced antigenicity loss. This applied treatment is efficient to modify the structure and to decrease the allergenicity of whey proteins.