Characterization of the Aroma Profile of Ginger Powder Produced by a Split-Stream Spray-Drying Process.

Freeze-dried ginger (Zingiber officinale) is renowned for its high quality, but it is expensive. As an alternative, spray drying can be explored for producing ginger powder. However, sugar rich feed solutions can lead to stickiness development during the process. Adding carrier materials increases costs and labeling. Accordingly, a split-stream spray-drying process was developed, where ginger fibers in their natural composition were reintroduced as a carrier material into the spray-drying process. The inlet and outlet temperatures were set at 220 and 80 °C, respectively, for optimal aroma retention. Using a stir bar sorptive extraction-gas chromatography-mass spectrometry-olfactometry, the results revealed that reintegrating ginger fibers significantly increased the concentration of eight key odorants. Although freeze-dried ginger retains more aroma, the total concentration of twenty-seven odorants in the developed spray-dried ginger was 1.9 times higher compared to frozen ginger.

Upcycling of Soy Whey with Ischnoderma benzoinum toward Production of Bioflavors and Mycoprotein.

Soy whey is becoming a worldwide issue as a liquid waste stream that is often discarded after tofu, soy protein, and soy-based dairy alternative manufacturing. This study established a model to produce a bioflavor and mycoprotein using fermentation of soy whey by a basidiomycete Ischnoderma benzoinum. Under the dedicated control of a fermentation system, an intense almond-like and sweetish aroma was perceived by a trained sensory panel (n = 10) after fermentation of pure soy whey within 20 h. By application of direct immersion-stir bar sorptive extraction combined with gas chromatography-mass spectrometry-olfactometry (DI-SBSE-GC-MS-O), around 1.0 mg/L benzaldehyde and 1.1 mg/L 4-methoxybenzaldehyde imparting a pleasant almond-like odor note were determined in the fermented soy whey with I. benzoinum. Concurrently, a certain of amount of the dry mass of I. benzoinum was accumulated with 73.2 mg/g crude protein and seven essential amino acids.

Influence of peeling on volatile and non-volatile compounds responsible for aroma, sensory, and nutrition in ginger (Zingiber officinale).

Industrial use of ginger after peeling results in large amounts of agro-waste. To provide a basic reference for the sustainable processing of ginger products as a spice, we investigated the differences between unpeeled ginger, peeled ginger, and corresponding ginger peel, in terms of aroma, sensory profiles, and nutrition relevant physicochemical properties. The results showed that the total concentrations of identified odor-active compounds in unpeeled ginger, peeled ginger, and ginger peel were 876.56, 672.73, and 105.39 mg/kg, respectively. Unpeeled ginger exhibited more intense citrus-like and fresh impressions compared to peeled ginger, revealed by descriptive sensory analyses. This is relevant to the high odor activity values of odorants such as ß-myrcene (pungent, citrus-like), geranial (citrus-like), citronellal (citrus-like, sourish), and linalool (floral, fresh). In parallel, unpeeled ginger contained higher total polyphenol (84.49 mg/100 g) and total sugar content (33.4 g/kg) in comparison with peeled ginger (76.53 mg/100 g and 28.6 g/kg).

Modeling and optimization of bakery production scheduling to minimize makespan and oven idle time.

Makespan dominates the manufacturing expenses in bakery production. The high energy consumption of ovens also has a substantial impact, which bakers may overlook. Bakers leave ovens running until the final product is baked, allowing them to consume energy even when not in use. It results in energy waste, increased manufacturing costs, and CO2 emissions. This paper investigates three manufacturing lines from small and medium-sized bakeries to find optimum makespan and ovens' idle time (OIDT). A hybrid no-wait flow shop scheduling model considering the constraints that are most common in bakeries is proposed. To find optimal solutions, non-dominated sorting genetic algorithm (NSGA-II), strength Pareto evolutionary algorithm (SPEA2), generalized differential evolution (GDE3), improved multi-objective particle swarm optimization (OMOPSO), and speed-constrained multi-objective particle swarm optimization (SMPSO) were used. The experimental results show that the shortest makespan does not always imply the lowest OIDT. Even the optimized solutions have up to 231 min of excess OIDT, while the makespan is the shortest. Pareto solutions provide promising trade-offs between makespan and OIDT, with the best-case scenario reducing OIDT by 1348 min while increasing makespan only by 61 min from the minimum possible makespan. NSGA-II outperforms all other algorithms in obtaining a high number of good-quality solutions and a small number of poor-quality solutions, followed by SPEA2 and GDE3. In contrast, OMOPSO and SMPSO deliver the worst solutions, which become pronounced as the problem complexity grows.

Characterization of hay-like off-odor in basil samples after various processing and strategies for reducing the off-odor.

Hay-like off-odor present in dried basil products results in low consumer acceptance. To understand the hay-like off-odor formation in processing of basil products, identification of hay-like off-odor in thawed, air-dried and spray-dried basil samples was investigated by means of a trained human panel (n = 10) and gas chromatography-mass spectrometry-olfactometry. 3-Methylnonane-2,4-dione (3-MND) was identified in all basil samples to be responsible for the hay-like off-odor. To reduce the hay-like off-odor in dried basil products, the effect of light, oxygen, and temperature on the 3-MND formation was studied during thawing, air drying and spray drying processes. In the thawing process, darkness and nitrogen protection significantly reduced the 3-MND formation. With extending thawing time, no significant increase on the concentration of 3-MND was observed after 60 min in the darkness and under nitrogen. In the designed spray-drying setup, nitrogen protection could further alleviate the 3-MND formation whereas the elevated drying temperature (40-100 °C) boosted the 3-MND formation in air-drying processing. Collectively, these findings indicated that darkness, nitrogen protection and low temperature were considered as critical processing parameters to minimize the generation of hay-like compound 3-MND in dried basil products.

Influence of Levan on the Thermally Induced Gel Formation of ß-Lactoglobulin.

In this study, the influence of levan on the phase behavior and the thermally induced gelation of the mixed ß-lactoglobulin-levan gels as a function of polymer content, molecular weight and ionic strength was characterized. For this purpose, rheology was used to study the mechanical properties of the gels and the water binding of the network structure was investigated by time domain nuclear magnetic resonance. Phase behavior and network type were analyzed by optical observation and electron microscopy. Levan enhanced the aggregation and gel formation of ß-lg due to segregative forces between the polymer species. Segregation was caused by the excluded volume effect and was more pronounced at lower ionic strength, higher levan contents and higher levan molecular weights. The presence of levan increased the water binding of the gel networks. However, this effect decreased with increasing levan content. At high ionic strength and high levan content, phase separated gels were formed. While segregative forces enhanced network formation, and therefore, increased the gel strength of mixed gels at low ionic strength, levan had also antagonistic effects on the network formation at high ionic strength and high polymer contents.

Impact of the oil load on the oxidation of microencapsulated oil powders.

The effect of the oil load on the oxidation of microencapsulated fish oil powders was investigated. The oil load was varied between 4.95 and 20.33%(w/w) by spray drying O/W emulsions with different oil to matrix ratios (0.05, 0.1, 0.15 and 0.2(w/w)), whereas solid content (45%(w/w)) and soy protein isolate to oil ratio (0.15(w/w)) were kept constant. A standardized size fraction of particles (50-80 µm) was stored for 82 days and hydroperoxides and anisidine value measured in the total- and encapsulated oil. Oxidation was limited by the oxygen amount rather than by the oil load. The absolute amount of oxidation products (per powder mass) increased with the oil load, which was explained by oxygen diffusion. Calculating oxidation products per oil mass resulted in a faster oxidation of the powder with 5% oil, whereas the oxidation rate for oil loads ≥10%(w/w) was similar, due to a scavenging effect of oil droplets.

Impact of the oil droplet size on the oxidative stability of microencapsulated oil.

Microencapsulation aims to protect polyunsaturated fatty acids against oxidation by embedding oil droplets in a solid matrix. The effect of the oil droplet size on the oxidation was evaluated under consideration of the non-encapsulated oil and the powder particle size. An O/W emulsion (1.6%(w/w) soy protein; 30.4%(w/w) maltodextrin DE21; 8%(w/w) fish oil) was homogenised at different pressure levels (4, 8, 17.5 and 30 MPa). Emulsions were spray dried and the size of the obtained powders was standardised. Powders were stored for 147 days at 25 °C and the hydroperoxide concentration and Anisidine Value in the total- and encapsulated oil measured. The volume mean diameter of oil droplets varied between 0.48 ± 0.01 and 1.54 ± 0.07 µm. Powders containing small oil droplets resulted in fewer oxidation products, which was related to a larger specific surface area and therefore a pronounced chemical stabilisation by soy protein isolate rather than oxygen diffusion phenomena or different encapsulation efficiencies.

Oxidation rate of the non-encapsulated- and encapsulated oil and their contribution to the overall oxidation of microencapsulated fish oil particles.

Microencapsulation of fish oil by spray drying is an established method to protect polyunsaturated fatty acids against oxidation by separating the environmental O2 from encapsulated lipids. Some oil droplets are not fully embedded within the matrix and are exposed to the environmental O2. The aim of the study is to determine the oxidation rate of the non-encapsulated- and encapsulated oil as well as the contribution of each lipid fraction to the overall oxidation of the encapsulates. The amount of non-encapsulated oil was varied by changing the preparation of the O/W emulsions (18% fish oil; 27% solids) regarding protein to oil ratio (0.02-0.22 (w/w)) and applied homogenization pressure (0.5/0.1-25/5 MPa). Emulsions were spray dried using a pilot plant drier with a maximal water evaporation rate of 30 kg h-1 operated at an inlet and outlet temperature of 160 °C and 85 °C, respectively. The obtained particles were analyzed in terms of water content, aw, particle size, non-encapsulated oil concentration and encapsulation efficiency. The amount of hydroperoxides in the total-, encapsulated- and non-encapsulated oil was determined over a storage period of 6 weeks. The non-encapsulated oil concentration was in the range of 2.20 and 18.45% which corresponds to an encapsulation efficiency between 53.82 and 93.56%. The sum of hydroperoxides in the non-encapsulated- and encapsulated oil equaled the amount detected in the total oil. The non-encapsulated oil oxidized on average 7.4 ±â€¯2.0 times faster than the encapsulated lipids, whereas its contribution to the overall oxidation was minor, due to its low amount. The encapsulated oil was the main contributor to the overall oxidation and oxidized, even though it was fully embedded within the matrix.

Influence of spray drying on the stability of food-grade solid lipid nanoparticles.

This study investigated spray drying of food-grade solid lipid particles (SLN) and nanostructured lipid carriers (NLC) containing ω-3 fish oil. Stable SLN and NLC dispersions with tristearin as carrier lipid were formed by using a combination of Quillaja saponins and high-melting lecithin as emulsifiers. Our specific goal was to study the influence of four different spray drying inlet and outlet temperatures (Tinlet/outlet = 140-170 °C/65-95 °C) and two different maltodextrin types (DE 6 and DE 21) with different molecular weights as protective wall materials on the physical and polymorphic stability of the solid lipid particles. The results revealed that the low molecular weight maltodextrin DE 21 was a superior wall material in stabilizing the solid lipid particles. Moreover, the lipid particles spray dried at Tinlet/outlet of 140/65 °C exhibited the highest physical and polymorphic stability, whereas using higher Tinlet/outlet led to bigger particles which were more prone to polymorphic transition. This was also verified in a 71-day storage test. The findings were explained that by preventing the melting of the tristearin carrier lipid during spray drying, the crystallized lipid particles remained intact inside the amorphous maltodextrin layer and exhibited high physical and polymorphic stability. These findings are important for generating stable food-grade spray dried powders.

Advanced characterisation of encapsulated lipid powders regarding microstructure by time domain-nuclear magnetic resonance.

Encapsulation is an established technique to protect sensitive materials from environmental stress. In order to understand the physical protection mechanism against oxidation, knowledge about the powder microstructure is required. Time domain-nuclear magnetic resonance (TD-NMR) has the potential to determine the surface oil (SO) and droplet size distribution by relaxation and restricted self-diffusion, respectively. The amount of SO, the retention and encapsulation efficiency are determined based on a lipid balance. The oil load of the initial powder and after SO removal is measured by TD-NMR. The results correlate with gravimetric and photometric references. The oil droplet size obtained by TD-NMR correlates well with static light scattering. The diameter of droplets in emulsions and dried powder both measured by TD-NMR, correlates (r = 0.998), implying that oil droplets embedded in a solid matrix can be measured. Summarising, TD-NMR allows analysis of the microstructure of encapsulated lipid powders, in a rapid, simple and non-destructive way.

Feasibility and energetic evaluation of air stripping for bioethanol production.

Stripping of mashes with air as stripping gas and low ethanol contents between 3 and 5wt% was investigated in terms of its suitability for continuous bioethanol production. Experiments in a Blenke cascade system were carried out and the results were compared with values obtained from theoretical vapour-liquid-equilibrium calculations. The whole stripping process was energetically evaluated by a simulation in ChemCAD and compared to conventional distillation. Therefore several parameters such as temperature, air volume flow and initial ethanol load of the mash were varied. Air stripping was found to be a suitable separation method for bioethanol from mashes with low concentrations. However, energetic aspects have to be considered, when developing a new process.

Meat batter production in an extended vane pump-grinder injecting curing salt solutions to reduce energy requirements: variation of curing salt amount injected with the solution.

BACKGROUND: The integration of a nozzle in an extended vane pump-grinder system may enable the continuous injection of curing salt solutions during meat batter production. The purpose of this work was to examine the influence of the curing salt amount injected with the solution (0-100%) on protein solubilisation, water-binding, structure, colour and texture of emulsion-type sausages. RESULTS: The amount of myofibrillar protein solubilised during homogenisation varied slightly from 33 to 36 g kg-1 . Reddening was not noticeably impacted by the later addition of nitrite. L* ranged from 66.9 ± 0.3 to 67.8 ± 0.3, a* from 10.9 ± 0.1 to 11.2 ± 0.1 and b* from 7.7 ± 0.1 to 8.0 ± 0.1. Although softer sausages were produced when only water was injected, firmness increased with increasing curing salt amount injected and was similar to the control when the full amount of salt was used. The substitution of two-thirds of ice with a liquid brine may enable energy savings due to reduced power consumptions of the extended vane pump-grinder system by up to 23%. CONCLUSION: The injection of curing salt solutions is feasible without affecting structure and colour negatively. This constitutes a first step towards of an 'ice-free' meat batter production allowing for substantial energy savings due to lower comminution work. © 2016 Society of Chemical Industry.

Inactivation kinetics of invertase in honey and honey-glucose syrup formulations: effects of temperature and water activity.

BACKGROUND: The high viscosity and stickiness of honey in its natural state causes handling difficulties, therefore the demand for honey powder is continuously increasing. Powder preparation has to be performed gently because of the thermo- and oxidation- sensitive nature of honey. The aim of this study was to determine the degradation of invertase during drying as an indirect measure of the retention of valuable honey nutrients. RESULTS: The reaction kinetics were estimated in polyfloral honey and honey-glucose syrup (GS) formulation and the impact of temperature (40-70°C) and water activity (aw 0.23-0.81) was established. The honey-GS formulation (55:45 w/w) was intended for the preparation of high-grade honey powders using the vacuum-drying method. Invertase inactivation at temperatures below 60°C followed first-order kinetics. At 60°C high dilution (aw 0.81) and at 70°C, heterogeneous inactivation behaviour was observed. The best fit of invertase heterogeneous inactivation kinetic was achieved with the Cerf two-fraction model. The GS addition showed a stabilizing effect on invertase during thermal degradation. CONCLUSION: The data on invertase inactivation gathered here can be utilized to select optimal parameters for honey vacuum-drying and other thermal processes in order to achieve maximum invertase retention. © 2016 Society of Chemical Industry.

Extension of the Vane Pump-Grinder Technology to Manufacture Finely Dispersed Meat Batters.

A vane pump-grinder system was extended to enable the manufacture of finely dispersed emulsion-type sausages by constructing and attaching a high-shear homogenizer at the outlet. We hypothesized that the dispersing capabilities of the extended system may be improved to the point of facilitating meat-fat emulsification due to an overall increased volumetric energy input EV . Coarsely ground raw material mixtures were processed to yield meat batters at varying volume flow rates (10 to 60 L/min) and rotational rotor speeds of the homogenizer nrotor (1000 to 3400 rpm). The normalized torques acting on pump, grinder, and homogenizer motors were recorded and unit power consumptions were calculated. The structure of the manufactured meat batters and sausages were analyzed via image analysis. Key physicochemical properties of unheated and heated batters, that is, texture, water-binding, color, and solubilized protein were determined. The mean diameter d10 of the visible lean meat particles varied between 352 and 406 µm whereas the mean volume-surface diameter d32 varied between 603 and 796 µm. The lightness L* ranged from 66.2 to 70.7 and correlated with the volumetric energy input and product structure. By contrast, varying process parameters did not impact color values a* (approximately 11) and b* (approximately 8). Interestingly, water-binding and protein solubilization were not affected. An exponential process-structure relationship was identified allowing manufacturers to predict product properties as a function of applied process parameters. Raw material mixtures can be continuously comminuted, emulsified, and subsequently filled into casings using an extended vane pump-grinder.

Preparation of High-Grade Powders from Tomato Paste Using a Vacuum Foam Drying Method.

We present a rapid and gentle drying method for the production of high-grade tomato powders from double concentrated tomato paste, comparing results with powders obtained by foam mat air drying and freeze dried powders. The principle of this method consists of drying tomato paste in foamed state at low temperatures in vacuum. The formulations were dried at temperatures of 50, 60, and 70 °C and vacuum of 200 mbar. Foam stability was affected by low serum viscosity and the presence of solid particles in tomato paste. Consequently, serum viscosity was increased by maltodextrin addition, yielding optimum stability at tomato paste:maltodextrin ratio of 2.4:1 (w/w) in dry matter. Material foamability was improved by addition of 0.5% (w/w, fresh weight) egg white. Because of solid particles in tomato paste, foam air filling had to be limited to critical air volume fraction of Φ = 0.7. The paste was first pre-foamed to Φ = 0.2 and subsequently expanded in vacuo. After drying to a moisture content of 5.6% to 7.5% wet base (w.b.), the materials obtained were in glassy state. Qualities of the resulting powders were compared with those produced by freeze and air drying. Total color changes were the least after vacuum drying, whereas air drying resulted in noticeable color changes. Vacuum foam drying at 50 °C led to insignificant carotenoid losses, being equivalent to the time-consuming freeze drying method. In contrast, air drying caused lycopene and ß-carotene losses of 18% to 33% and 14% to 19% respectively. Thus, vacuum foam drying enables production of high-grade tomato powders being qualitatively similar to powders obtained by freeze drying.

Modulation of collagen by addition of Hofmeister salts.

Collagen can be modified by addition of chaotropic or kosmotropic salts of the reversed Hofmeister series. Hence, telopeptide-poor collagen type I was suspended in H2SO4 (pH 2) and 0.05-0.5 M KCl and KNO3 (chaotropes), as well as KI and KSCN (kosmotropes). Rheological parameters, including storage and loss modulus, intrinsic viscosity, and critical overlap concentration, were assessed and the microstructure was characterized by applying confocal laser scanning microscopy and scanning electron microscopy. The addition of up to 0.1 M KCl and 0.05 M KNO3 increased the intrinsic viscosity from 1.22 to 1.51 L/g without salt to a maximal value of 1.74 L/g and decreased the critical overlap concentration from 0.66 to 0.82 g/L to a minimal value of 0.57 g/L. Higher salt concentrations increased the collagen-collagen interactions due to ions withdrawing the water from the collagen molecules. Hence, 0.1 M KSCN delivered the largest structures with the highest structure factor, area value and the highest critical overlap concentration with 17.6 L/g. Overall, 0.5 M salt led to salting out, with chaotropes forming fine precipitates and kosmotropes leading to elastic three-dimensional networks. The study demonstrated that collagen entanglement and microstructure depend strongly on the ionic strength and type of salt.

Presence of electrostatically adsorbed polysaccharides improves spray drying of liposomes.

UNLABELLED: Spray drying of liposomes with conventional wall materials such as maltodextrins often yields nonfunctional powders, that is, liposomes break down during drying and rehydration. Electrostatically coating the surface of liposomes with a charged polymer prior to spray drying may help solve this problem. Anionic lecithin liposomes (approximately 400 nm) were coated with lower (approximately 500 kDa, LMW-C) or higher (approximately 900 kDa, HMW-C) molecular weight cationic chitosan using the layer-by-layer depositing method. Low (DE20, LMW-MD) or high molecular weight (DE2, HMW-MD) maltodextrin was added as wall material to facilitate spray drying. If surfaces of liposomes (1%) were completely covered with chitosan (0.4%), no bridging or depletion flocculation would occur, and mean particle diameters would be approximately 500 nm. If maltodextrins (20%) were added to uncoated liposomes, extensive liposomal breakdown would occur making the system unsuitable for spray drying. No such aggregation or breakdown was observed when maltodextrin was added to chitosan-coated liposomes. Size changed little or even decreased slightly depending on the molecular weight of maltodextrin added. Scanning electron microscopy images of powders containing chitosan-coated liposomes revealed that their morphologies depended on the type of maltodextrin added. Powders prepared with LMW-MD contained mostly spherical particles while HMW-MD powders contained particles with concavities and dents. Upon redispersion, coated liposomes yielded back dispersions with particle size distributions similar to the original ones, except for LMW-C coated samples that had been spray dried with HMW-MD which yielded aggregates (approximately 30 µm). Results show that coating of liposomes with an absorbing polymer allows them to be spray dried with conventional maltodextrin wall materials. PRACTICAL APPLICATION: Liposomes have attracted considerable attention in the food and agricultural, biomedical industries for the delivery of functional components. However, maintaining their stability in aqueous dispersion represents a challenge for their commercialization. Spray drying may promise a solution to that problem. However, prior to this study spray drying of liposomes often led to the loss of structural integrity. Results of this study suggest that spray drying might be used to produce commercially feasible liposomal powders if proper combinations of adsorbing and nonadsorbing polymers are used in the liquid precursor system.

Impact of carboxymethyl cellulose (CMC) and microcrystalline cellulose (MCC) on functional characteristics of emulsified sausages.

Inclusion of fibers, such as carboxymethyl cellulose (CMC) and microcrystalline cellulose (MCC), at the expense of fat or protein in meat batters could be used to produce healthier sausages while lowering production costs. To study the impact of CMC/MCC on structural/functional characteristics of emulsified sausages, standard-fat Lyoner-style sausages were formulated with CMC/MCC at concentrations of 0.3-2.0%. Methods of analysis included rheology, water binding capacity (WBC), texture measurements, and Confocal Laser Scanning Microscopy (CLSM). WBC, texture measurements, and rheology all indicated that addition of CMC (>0.7%) led to destabilization of the batter, which upon heating could no longer be converted into a coherent protein network, a fact that was also revealed in CLSM images. In contrast, MCC was highly compatible with the matrix and improved firmness (1405-1651N/100g) with increasing concentration compared to control (1381N/100g) while keeping WBC (4.6-5.9%) with <2% MCC at the level of the control (4.8%). Results were discussed in terms of molecular interactions of meat proteins with celluloses.

Efficiency of Blenke cascade system for continuous bio-ethanol fermentation.

A gas lift-system with inserts (so-called Blenke cascade system) for continuous bio-ethanol fermentation was constructed. Gas introduced at the bottom of the column created toroidal vortices in the fluid cells between inserts, enhancing mixing and improving residence time behavior without stirring equipment being necessary. The parameters mash type, start-up strategy, yeast-recycle model and yeast separation were studied concerning the efficiency of the ethanol production. The best results obtained were for a filtered mash, a double saccharification principle (DSP), a batch start-up strategy, an activation-recycle model and a lamella settler connected in series with a small conventional gravitational settler for yeast cells separation. Using this system, the fermentation residence time was τ=4-5.5h, depending on substrate type. Eighty five percent of the yeast cells could be separated. High volumetric ethanol productivity (Q(p)=20.43g/Lh) and yield E(y)=98% were achieved. Continuous fermentation, yeast recycling and sedimentation were contamination-free processes.