Study of the microencapsulation of camu-camu (Myrciaria dubia) juice

Encapsulation of W/O/W Acerola Emulsion by Spray Drying: Optimization, Release Kinetics, and Storage Stability

Acerola (Malpighia emarginata DC.) is a sub-tropical and tropical fruit renowned for its high levels of vitamin C and phenolic compounds, which offer health benefits. This study aimed to optimize the spray drying process by determining the inlet and outlet temperatures using response surface methodology (RSM) with the central composite design. Additionally, it aimed to evaluate the release kinetics in the hydrophilic food simulation environment and the stability of the resulting powder under various storage temperatures. The RSM method determined the optimal inlet and outlet temperatures as 157 °C and 91 °C, respectively. High-accuracy prediction equations (R2 ≥ 0.88) were developed for moisture content (3.02%), process yield (91.15%), and the encapsulation yield of total polyphenol content (61.44%), total flavonoid content (37.42%), and vitamin C (27.19%), with a predicted monolayer moisture content below 4.01%, according to the BET equation. The powder exhibited good dissolution characteristics in the acidic hydrophilic food simulation environment and showed greater stability when stored at 10 °C for 30 days, compared to storage at 35 °C and 45 °C.

Effects of drying methods and maltodextrin on vitamin C and quality of Terminalia ferdinandiana fruit powder, an emerging Australian functional food ingredient

BACKGROUND

Terminalia ferdinandiana, common name Kakadu plum (KP), fruit is a valuable source of vitamin C, and its concentration can be used as a quality index of KP products, such as dried fruit powder. The present study investigated the effects of two drying methods (freeze-drying and oven-drying) and the addition of maltodextrin (0-25%) on vitamin C, Maillard products, and overall quality of KP fruit powder.

RESULTS

Freeze-drying was a better dehydration technique than oven-drying in retaining vitamin C, reducing the formation of non-enzymatic browning and oxidation products, and improving powder colour (P < 0.05). Non-enzymatic browning products (furfural and 5-hydroxymethyl furfural) were generated in the oven-dried samples as a function of heating and high water activity. Maltodextrin acted as a vitamin C stabilizer in protecting vitamin C from oxidation, and significantly improved the colour attributes of the final dry products. Incorporation of 10-15% maltodextrin could reduce the percentage loss of vitamin C from 8.1% to 3.4% and 18.9% to 11.4% (compared with the control) during freeze-drying and oven-drying, respectively. Scanning electron micrographs revealed differences in the microstructures of the KP powder processed by the two drying methods with different levels of maltodextrin. Multivariate data analysis (principal component analysis) showed separation between the oven-dried and freeze-dried samples, and also suggested that addition of maltodextrin of 7.5-10% and 10-15% are effective for preserving vitamin C and other quality properties of the freeze- and oven-dried KP powder samples, respectively.

CONCLUSION

The results obtained are important for the KP industry, including Indigenous enterprises, in selecting the most appropriate drying method for KP fruit in terms of quality and sustainability. © 2021 Society of Chemical Industry.

Vitamin C stability in acerola and camu-camu powder obtained by spray drying

Abstract Acerola and camu-camu fruits possess high vitamin C content. However, since these fruits are little consumed in their fresh form, it is important to consider that vitamin C can be oxidized depending on storage conditions. Thus, this study aimed to produce acerola and camu-camu powders by spray drying to maintain the stability of their vitamin C content during storage. Acerola and camu-camu powders were characterized in relation to their physicochemical characteristics, antioxidant activity, and vitamin C concentration and stability under different storage conditions (30 °C and 40 °C, 75% relative humidity). In general, the powders were proven to be stable, with low water activity (< 0.40) and humidity (< 4.0 g/100 g powder), as well as high vitamin C concentrations (1593.2 and 6690.4 mg/100 g of powder for acerola and camu-camu, respectively). Furthermore, we observed a high antioxidant activity by ABTS●+, DPPH• and FRAP assays. The powders stored at lower temperature (30 °C) showed higher vitamin C stability. In conclusion, acerola and camu-camu powders produced by spray drying are potential sources of vitamin C and active compounds and are therefore suitable for several food industry applications.

Effects of Spray-Drying Parameters on In Vitro Functional Properties of Camu-Camu (Myrciaria dubia Mc. Vaugh): A Typical Amazonian Fruit

Camu-camu (Myrciaria dubia) fruit is a rich source of bioactive compounds but its shelf life is rather short. Therefore, this study was aimed to evaluate the effect of inlet air temperature (T) and concentration (C) of maltodextrin and arabic gum on the spray-drying process of commercial camu-camu pulps (São Paulo and Manaus). Moisture, solubility, total phenolics (TP), ascorbic acid (AA), and proanthocyanidins (PAC) contents, and in vitro antioxidant capacity of the powders (FRAP, DPPH, Folin-Ciocalteu's reducing capacity were measured). Arabic gum resulted in better yields (22% to 30%), powder solubility (84% to 90%), and lower losses of analyzed compounds than the powders manufactured with maltodextrin. Overall, inlet air temperature had a lower impact on the responses studied than the concentration of carrier agents. Polynomial equations were generated for AA (R² = 0.993), TP (R² = 0.735), PAC (R² = 0.946), and for the antioxidant capacity assays (0.867 ≤ R²  ≤ 0.963). In addition, principal component analysis showed that the lowest concentration of carrier agents (6%) in spray drying resulted in the lowest losses of bioactive compounds and, consequently, the highest antioxidant capacity.

Physicochemical, functionality and storage stability of hog plum (Spondia pinnata) juice powder produced by spray drying

Hog plum juice powder was obtained from its juice under optimized condition by spray drying with juice: maltodextrin ratio at 2:1, 4:1 and 6:1 (v/w) basis. The inlet temperature and feed rate were varied between 120 to 175 °C and 8 to 14 mL/min. The effect of variables i.e. maltodextrin level, temperature and feed rate on the physicochemical properties and total phenolic content were studied. Moisture content, hygroscopicity, bulk density, water activity and total phenolic content of the powder were significantly affected by inlet temperature and maltodextrin level. However feed rate showed no any significant effect on the bulk density of the powder. An increase in inlet temperature and maltodextrin level reduced the total phenolic content in the spray dried powder. Morphological study showed that at high inlet temperature the spray dried powder were of smooth surfaces however, at low inlet temperature majority of the particles were of shrivelled surfaces. Spray dried hog plum juice powder made with 3.9:1 juice: maltodextrin, processed at 171 °C inlet temperature and at 8 mL/min feed rate had less hygroscopicity, water activity, moisture content and potent TPC content. Storage temperature significantly affected the TPC and DPPH free radical scavenging activity of the powder. Refrigeration temperature was found to be more effective to reduce the losses of TPC and DPPH free radical scavenging activity during storage. Colour acceptability of the refrigerated sample was comparatively more than to the sample stored at room temperature.

Encapsulation of black carrot juice using spray and freeze drying

Black carrot juice extracted using pectinase enzyme was encapsulated in three different carrier materials (maltodextrin 20DE, gum arabic and tapioca starch) using spray drying at four inlet temperatures (150, 175, 200 and 225 ℃) and freeze drying at a constant temperature of − 53 ℃ and vacuum of 0.22–0.11 mbar with the constant feed mixture. The products were analyzed for total anthocyanin content, antioxidant activity, water solubility index, encapsulation efficiency and total colour change. For both the drying methods followed in this study, maltodextrin 20DE as the carrier material has proven to be better in retaining maximum anthocyanin and antioxidant activity compared to gum arabic and tapioca starch. The best spray dried product, was obtained at 150 ℃. The most acceptable was the freeze dried product with maximum anthocyanin content, antioxidant activity, water solubility index, encapsulation efficiency and colour change.

Antioxidant activity, total phenolics content, anthocyanin, and color stability of isotonic model beverages colored with Andes berry (Rubus glaucus Benth) anthocyanin powder

The stability of anthocyanin (ACN) freeze-dried powders from Andes berry (Rubus glaucus Benth) as affected by storage, addition of maltodextrin as a carrier agent, and illumination was evaluated in isotonic model beverages. The ethanolic ACN extract was freeze dried with and without maltodextrin DE 20. Isotonic model beverages were colored with freeze-dried ACN powder (FDA), freeze-dried ACN powder with maltodextrin (MFDA), and red nr 40. Beverages were stored in the dark and under the effect of illumination. Half life of the ACNs, changes in color, total phenolics content (TPC), and antioxidant activity were analyzed for 71 d. Addition of maltodextrin and absence of light stabilized the color of beverages and improved ACN and TPC stability during storage. The antioxidant activity of the beverages was higher when they were colored with MFDA and highly correlated with ACN content. There was no correlation between antioxidant activity and TPC. It is concluded that addition of maltodextrin DE 20 as a carrier agent during freeze-drying improves the color and stability of nutraceutical antioxidants present in Andes berry extract. This suggests a protective enclosing of ACNs within a maltodextrin matrix with a resulting powder that could serve as a supplement or additive to naturally color and to enhance the antioxidant capacity of isotonic beverages.

Microencapsulation by spray-drying of anthocyanin pigments from Corozo ( Bactris guineensis) fruit

The anthocyanins of Bactris guineensis fruit were isolated with the aid of high-speed countercurrent chromatography (HSCCC) and preparative HPLC, and their chemical structures were elucidated by using spectroscopic methods. Among the identified pigments, cyanidin-3-rutinoside and cyanidin-3-glucoside were characterized as major constituents (87.9%). Peonidin-3-rutinoside, peonidin-3-glucoside, cyanidin-3-(6-O-malonyl)glucoside, and cyanidin-3-sambubioside were present in minor amounts. Four anthocyanin ethanolic extracts (AEEs) were obtained by osmotic dehydration and Soxhlet extraction and physicochemically characterized. The composition of anthocyanins was monitored by HPLC-PDA. The extracts with the highest anthocyanin content were subjected to the spray-drying process with maltodextrin. The so-obtained spray-dried powders were analyzed by scanning electron microscopy (SEM) and found to consist of spherical particles <50 microm in size. The anthocyanin composition was similar to that of the fruit. The microencapsulated powders were analyzed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), revealing that they are quite stable until 100 degrees C. Storage stability tests of microcapsules showed that the release of anthocyanin pigments follows pseudo-first-order kinetics and that the process rate is increased by temperature and humidity. The most suitable conditions for storage were below 37 degrees C and <76% relative humidity, respectively.