Optimisation of pomegranate (Punica Granatum L.) juice spray‐drying as affected by temperature and maltodextrin content

Pomegranate juice powder is easier to handle and has more potential applications than the concentrate. In this study, the response surface, 3‐level factorial design was used to evaluate the influence of spray‐drying conditions on the physicochemical properties of a powdered product obtained by drying pomegranate juice concentrate (PJC). It was spray‐dried with a lab‐scale spray‐dryer using 18 and 7 dextrose equivalent (DE) maltodextrins (MD) as drying‐aid agents. Adding MD significantly reduced the hygroscopicity and stickiness of the pomegranate juice powder, and thus yielded higher recovery. The maximum achieved ratio of PJC/MD was 1/1, and it was obtained with the use of DE7 MD. However, graphical optimisation studies resulted in 125–145 °C and 0.6–0.8 PJC/MD ratio as optimum variables to produce acceptable dried powder. The results indicated that increasing inlet air temperature increases solubility time and loss of anthocyanins and decreases bulk density and moisture content of the powder.     

Quality and antioxidant properties of a reduced-sugar pomegranate juice jelly with an aqueous extract of pomegranate peels

In the present study, the production of a reduced-sugar pomegranate juice jelly supplemented with an aqueous extract of pomegranate peel (PE) is described. Influence of different carbohydrate polymers (guar (G), xanthan (X) and tragacanth (T) gums) on rheological properties was studied. Combination GXT presented the most similar rheological behaviour to commercial jelly. Jelly (J) and jelly with PE (JE) were stored at 4 °C over an 8 week period for physical, chemical, antioxidant, microbiological and sensory analysis. J and JE showed similar values for °Brix, colour and Aw, though the pH of JE was lower than J. Thiol and phenolic compounds were higher in JE than in J. Antioxidant activity (radical scavenging activity and autoxidation of linoleic acid) was higher in JE than in J at 0 weeks, and were decreasing with time. Pomegranate juice with additives was generally less accepted than J and JE.     

Spray‐Dried Structured Lipid Containing Long‐Chain Polyunsaturated Fatty Acids for Use in Infant Formulas

Human milk fat (HMF) analogs are structured lipids (SLs) modified to have palmitic acid content at the sn‐2 position of the triacylglycerol (TAG) and fatty acid composition comparable to HMF. Some of these SLs are also designed to incorporate long‐chain polyunsaturated fatty acids (LCPUFAs) because of their important role in infant development. In this study, Maillard reaction products (MRPs), obtained from heated whey protein isolates and corn syrup solids (CSS) solution, were used as encapsulants for microencapsulation of 2 enzymatically synthesized SLs for infant formula applications. The encapsulated SL powders were obtained through spray‐drying and evaluated in terms of their microencapsulation efficiency, chemical and physical properties, oxidative stability, and dispersibility. The microencapsulation efficiency of the SLs was 90%. Dispersibility test using particle size measurement demonstrated that these powders dispersed quickly into a homogeneous suspension. The encapsulated SL powders had low peroxide and thiobarbituric acid‐reactive substances values. Lower oxidative stability was obtained in the powder containing SL with a higher degree of unsaturation and a lower concentration of tocopherols. The results demonstrated that the degree of fatty acid unsaturation and concentration of endogenous antioxidant in starting oils influenced the oxidative stability of the encapsulated SLs.     

Spray‐drying for the production of dried cultures

This review emphasises the importance of spray‐drying as an under‐used but promising technique to preserve viable and active starter cultures and also, potentially, probiotic cultures. The knowledge concerning the production of spray‐dried starter cultures is discussed. Different drying techniques and micro‐organisms have been investigated for their survival through the drying process. During drying and subsequent storage in the dried state, bacteria are subjected to several stresses, which have already been described as causing damage to cells, leading to the loss of cellular viability and activity. Some studies found that several factors/strategies can confer improved cellular viability.     

Spray‐drying encapsulation of citral in sucrose or trehalose matrices: physicochemical and sensory characteristics

The potential of the disaccharide trehalose as carrier for producing spray‐dried citral was examined. Some physical and sensory characteristics of citral encapsulated in matrices containing either trehalose or sucrose and maltodextrin (MD) were analysed. They included water sorption, glass transition temperatures (T_g), nuclear magnetic resonance (NMR) relaxation and citral retention during spray‐drying. The glassy state at room temperature (25 °C) was maintained as far as 33% relative humidities (RH) for the spray‐dried trehalose formulation and 43% RH for trehalose–MD; however, for sucrose–MD and for sucrose formulations, the glassy state was limited to RHs lower than 33% and 22%, respectively. Sensory evaluation and gas chromatographic analysis indicated that citral retention after spray‐drying was similar for matrices containing either trehalose or sucrose. However, trehalose formulations had improved physical stability as compared to sucrose.     

Microencapsulation of Nigella sativa seeds oil containing thymoquinone by spray‐drying for functional yogurt production

The present work reports on the microencapsulation of Nigella sativa seeds oil containing thymoquinone (TQ) by spray‐drying, using modified starch (MS) and maltodextrin (MD) mixture as wall materials aimed at producing functional yogurt. First, the impact of different ratios of MS/MD on microencapsulation efficiency (ME) and TQ retention was investigated. The highest ME (90.10%) was found in microcapsules prepared from emulsion with 80/20 ratio of MS/MD; however, the microcapsules prepared with 50/50 ratio was selected for considering TQ stability under storage conditions and functional yogurt production due to an acceptable ME (89.48%) and better TQ retention (61.12%). The results showed that the microcapsules stored at refrigerator temperature had the highest content of TQ after 4 weeks. Moreover, the results of chemical and sensory analysis suggest that N. sativa seeds oil microcapsules can be used for producing functional yogurt due to high stability of TQ and proper chemical and sensory properties.     

Physical and chemical properties of encapsulated rosemary essential oil by spray drying using whey protein–inulin blends as carriers

The objective of this study was to evaluate the influence of whey protein isolate (WPI) and inulin blends on the properties of rosemary essential oil microencapsulated by spray drying. The following ratios (w/w) of WPI to inulin were evaluated: 1:1, 1:3 and 3:1. Increasing the WPI concentration increased the particle instantanisation times and decreased the moisture content. The samples did not differ significantly (P > 0.05) in hygroscopicity and porosity. The microcapsules produced at higher inulin concentration showed the highest bulk density and tapped density and were significantly different from other treatments. WPI/inulin blends of 1:1 and 3:1 proved to be effective carriers to entrap rosemary essential oil. The encapsulated oil composition in particles proved to be quite similar to pure oil, and no interaction between wall matrix and encapsulated oil was demonstrated. The analysis of particle size distribution revealed that the particle size varied from 11.5 to 11.9 μm and that all samples had an amorphous structure.     

Effects of the spray drying conditions of chokeberry (Aronia melanocarpa L.) juice concentrate on the physicochemical properties of powders

A semi‐industrial spray drying process of chokeberry juice concentrate using maltodextrin was analysed. The influence of the content and dextrose equivalent (DE) of maltodextrin, inlet air temperature and rotary disc atomiser speed was studied on the physicochemical properties of the obtained powders. The size and structure of the powder particles, bulk density, moisture content, flowability, yield and total polyphenol content were analysed. An increase in carrier content from 50% to 70% caused a 4.9% increase in total polyphenol retention, better flowability (Hausner ratio decrease of 0.17) and greater yield of the powder (60%). An increase in the drying temperature (150–170 °C) caused larger particle size and improved powder flowability but also resulted in greater loss of total polyphenols. A decrease in rotary atomiser speed (11 000–15 000 rpm) had a moderate influence on particle size and improvement in flowability but had no effect on polyphenol retention. Changes in the DE (8–22) of maltodextrin as a carrier indicated a moderate growing dependence on particle size and worse flowability.     

Structural characteristics,physicochemical properties and prebiotic potential of modified dietary fibre from the basal part of bamboo shoot

The basal part of bamboo shoot is a novel resource to produce dietary fibre (BDF). However, its insolubility in water, stiff texture and low degradability limit its applicability in foods. This study explored the feasibility of improving the structural and functional properties of BDF by enzymatic hydrolysis and dynamic high-pressure micro-fluidisation (DHPM). Both methods are efficient to reduce the fibre particle size and caused significantly increased roughness on the fibre surface, especially for the porous structure after DHPM treatment. Crystallinity of DHPM-modified fibres was increased from 23.01% to 33.53%, due to the disruption of lignin and hemicellulose, which was further confirmed by the FT-IR spectra. The modified fibres exhibited significantly enhanced swelling capacity and holding water/oil capacities. Moreover, the modified fibres exhibited improved in vitro prebiotic property, which could constantly supply the carbon source and stimulate the growth of Lactobacillus acidophilus ATCC 4356 and Bifidobacterium longum ATCC 15707.     

The influence of the carrier addition and spray drying temperatures on physicochemical properties of microencapsulated carrot juice powder

The objective of this study was to determinate the influence of carrier addition and spray drying temperatures (160 or 200°C) on physicochemical properties of spray-dried carrot juice powder. As carriers, maltodextrin and gum Arabic in different proportions were used. In powders were determined the following: moisture content, water activity, apparent density, size of particles, colour and carotenoids content. The content of carotenoids in powders prepared from solutions with juice to carrier ratio 2:3 was 324.3–406.6 mg/kg d.m., while in powders with a J:C = 3:2 values ranged from 576.7 to 637.7 mg/kg d.m. The highest content of carotenoids and the most yellow colour were observed in powders with 1:3 gum Arabic to maltodextrin ratio. Powders with the highest amount of gum Arabic have the highest diameter and the lowest water activity. High inlet temperature caused brighter colour of powders, higher dry matter content, lower water activity and apparent density of powders.     

Development of ready‐to‐eat rice starch‐based puffed products by coupling freeze‐drying and microwave

The rice starch mixtures with varying amylose contents (AC) of 0.12–19.00% weight were prepared by mixing waxy and nonwaxy rice starches. The 5% rice bran oil shortening was added in the starch paste. After gelatinisation, thin slabs of starch pastes were aged at 4 °C for 24 h. The aged slabs were dried by freeze‐drying to obtain 25% moisture content. A microwave oven set to 600 J s^?1 for 90 s was then used for puffing. The crucial factors affecting the snack purchase were texture and nutrition. The relative crystallinity and retrogradation enthalpy (?H_r) of freeze‐dried pellets increased with increasing the AC. From using a differential scanning calorimeter (DSC), endotherms of pellets were shown only when AC > 0.12%. An amylose–lipid complex was shown in pellets with AC ≥ 9.00%. Relationships between the AC and all puffed product properties were linear. Increasing AC provided greater hardness, fracturability, bulk density, but lower expansion ratio. From the sensory evaluation, the panellists preferred the puffed products with 9.00% AC. Increasing the AC gave higher crispness, hardness, brittleness, air cell opacity and density, but resulted in less puffiness. Thus, the microwave drying has the potential to puff a healthy expanded snack but giving the desirable properties depends on AC.     

Addition of cashew tree gum to maltodextrin-based carriers for spray drying of cashew apple juice

This study involved an attempt to totally or partially replace maltodextrin DE10 (MD10) by cashew tree gum (CTG) as a drying aid agent in spray drying of cashew apple juice. The objective was to evaluate the impact of drying aid/cashew apple juice dry weight ratio (D/C, ranging from 3 to 5) and degree of replacement of MD10 with CTG (CTG_R, ranging from 0% to 100%) on ascorbic acid retention (AAR), hygroscopicity, flowability and water solubility of spray dried cashew apple juice powder. AAR was increased from 72.90% to 95.46% by increasing D/C from 3 to 5. CTG was shown as a promising maltodextrin replacer, being more effective than the latter to decrease powder hygroscopicity. The most adequate drying conditions (D/C = 5, CTG_R≥50%) resulted in more than 90% of AAR, and produced a powder with good flowing properties and water solubility.     

Spray-drying microencapsulation of pomegranate juice increases its antioxidant activity after in vitro digestion

Most of the work on pomegranate antioxidant and antibacterial activity has been carried out with solvent extracts of different plant or fruit parts. Biosensitive compounds in juice may be subject to oxidation, reducing their biological activities. Microencapsulation can be used to protect compounds, allowing its incorporation into functional foods. This study aimed at investigating antioxidant activity after in vitro digestion of microencapsulated juice. Pomegranate juice was encapsulated by spray drying its maltodextrin and gum arabic. The average diameter of the microcapsules was 10–50 µm. We evaluated the bioaccessibility of microencapsulated phenolic compounds by using an in vitro enzymatic digestion. The total phenolic content in digested microencapsulated juice was three times greater than in undigested, indicating that the compounds were made bioaccessible. Digestion also increased antioxidant activity, as measured by ABTS●+ or by DPPH●. Additionally, microencapsulated pomegranate juice showed antibacterial activity against the nine bacteria species tested.     

Spray drying conditions for orange juice incorporated with lactic acid bacteria

This work aimed to develop an orange juice powder by spray drying with lactic acid bacteria (Lactobacillus plantarum 299v and Pediococcus acidilactici HA‐6111‐2), testing their survival both during drying and storage (room temperature and 4 °C). Initially, the best conditions for spray drying were chosen to allow the best survival of each LAB: (i) inlet air temperature of 120 °C and (ii) 0.5:2 ratio of the orange juice soluble solids and drying agent added (prebiotics: 10 DE maltodextrin or gum Arabic). Survival of LAB was not affected by drying process, and it was higher when cultures were stored at 4 °C. A slightly higher protection was conferred by 10 DE maltodextrin, in the case of L. plantarum and at 4 °C. Pediococcus acidilactici was more resistant during storage at 4 °C, with logarithmic reductions lower than 1 log‐unit. It was demonstrated that it is possible to produce a functional nondairy product, orange juice powder supplemented with prebiotic compounds, containing viable LAB for at least 7 months, when stored at 4 °C.     

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.     

Liposomes encapsulating beta‐carotene produced by the proliposomes method: characterisation and shelf life of powders and phospholipid vesicles

The objective of this study was to investigate the feasibility of producing proliposomes incorporating beta‐carotene by spray drying and to assess the capacity of the liposomes produced by the hydration of the dry phospholipid particles to preserve the encapsulated carotenoid. Powders containing beta‐carotene, hydrogenated phosphatidylcholine and sucrose were obtained and characterised in terms of crystallinity, morphology, thermal behaviour, density, solubility and hygroscopicity. The preservation of beta‐carotene in the powder was evaluated for two storage conditions under normal atmosphere and vacuum. The proliposome was highly soluble, with all components embedded in the matrix and capable of preserving more than 90% of the incorporated beta‐carotene for 60 days of refrigerated storage under vacuum. The liposome dispersions maintained their average size, polydispersity index and zeta potential for 100 days of storage. After 60 days, the degradation of encapsulated beta‐carotene was minimal, and the colour of the dispersions was preserved.