Stability of β-Carotene in Oil-in-Water Emulsions Prepared by Mixed Layer and Bilayer of Whey Protein Isolate and Beet Pectin

Combination of Spray-Chilling and Spray-Drying Techniques to Protect Carotenoid-Rich Extracts from Pumpkin (Cucurbita moschata) Byproducts, Aiming at the Production of a Powdered Natural Food Dye

Reducing waste, using byproducts, and natural food additives are important sustainability trends. In this context, the aim of this study was to produce and evaluate a natural food dye, extracted from pumpkin byproducts, powdered and protected by spray-chilling (SC) and a combination of spray-drying and spray-chilling techniques (SDC). The extract was obtained using ethanol as solvent; vegetable fat and gum Arabic were used as carriers. Formulations were prepared with the following core:carrier ratios: SC 20 (20:80), SC 30 (30:70), SC 40 (40:60), SDC 5 (5:95), SDC 10 (10:90), and SDC 15 (15:85). The physicochemical properties of the formed microparticles were characterised, and their storage stability was evaluated over 90 days. The microparticles exhibited colour variation and size increase over time. SDC particles exhibited the highest encapsulation efficiency (95.2-100.8%) and retention of carotenoids in the storage period (60.8-89.7%). Considering the carotenoid content and its stability, the optimal formulation for each process was selected for further analysis. All of the processes and formulations produced spherical particles that were heterogeneous in size. SDC particles exhibited the highest oxidative stability index and the highest carotenoid release in the intestinal phase (32.6%). The use of combined microencapsulation technologies should be considered promising to protect carotenoid compounds.

Influence of Type and Concentration of Biopolymer on β-Carotene Encapsulation Efficiency in Nanoemulsions Based on Linseed Oil

Many lipophilic active substances, such as β-carotene, are sensitive to chemical oxidation. A strategy to protect these ingredients is encapsulation using nanoemulsions. This work analyzes the relationship between the physical stability and encapsulation efficiency of nanoemulsions based on linseed oil. The role of two different polysaccharides, Advanced Performance xanthan gum (APXG) or guar gum (GG) as stabilizers at different concentrations were studied to reach the required physical stability of these systems. This was investigated by means of droplet size distributions, steady-state flow curves, small amplitude oscillatory shear tests, multiple light scattering, and electronic microscopy. The overall results obtained reveal a depletion flocculation mechanism in all the APXG nanoemulsions, regardless of the concentration, and above 0.3 wt.% for GG nanoemulsions. Moreover, it has been demonstrated that enhanced physical stability is directly related to higher values of encapsulation efficiency. Thus, the nanoemulsion formulated with 0.2 wt.% GG, which presented the lowest creaming degree conditioned by depletion flocculation, showed a relative β-carotene concentration even above 80% at 21 days of aging time. In conclusion, the adequate selection of polysaccharide type and its concentration is a key point for the application of stable nanoemulsions as vehicles for active ingredients.

Production of a rich-carotenoid colorant from pumpkin peels using oil-in-water emulsion followed by spray drying

Peels and seeds are byproducts generated during the processing of fruits and vegetables that have been cut off or rejected in the food industry. Pumpkin peels are an example of products that provide valuable nutritional aspects but that have low commercial value. This work aimed at recovering carotenoids from pumpkin peels to produce valuable powders. The pumpkin peel flour was obtained from convective drying and milling processes. Liquid-solid extraction produced the ethanol raw extract with a high carotenoid content. Carotenoid extract and Arabic gum suspensions were mixed in proportions of 1:2, 1:3, or 1:4 w/w. Emulsions produced via Ultra-Turrax (UT) and Ultra-Turrax plus high pressure (UTHP) were evaluated and spray dried. The particles carotenoid concentrations varied from 159.1 to 304.6 µg/g and from 104.3 to 346.2 µg/g for samples primarily produced via UT and UTHP, respectively. UTHP 1:3 particles showed the lowest degradation of carotenoids during 90 days of storage, with a retention index of 79%. The homogenization and spray drying techniques were proven to be suitable steps to preserve the carotenoids recovered from the byproduct studied. Microparticles can be used as a natural dye with potential use in food, pharmaceuticals, and cosmetics.

Physicochemical Properties and Chemical Stability of β-Carotene Bilayer Emulsion Coated with Bovine Serum Albumin and Arabic Gum Compared to Monolayer Emulsions

β-carotene is a lipophilic micronutrient that is considered beneficial to human health. However, there are some limitations in utilizing β-carotene in functional foods or dietary supplements currently because of its poor water dispersibility and chemical stability. A new type of β-carotene bilayer emulsion delivery system was prepared by a layer-by-layer electrostatic deposition technique, for which were chosen bovine serum albumin (BSA) as the inner emulsifier and Arabic gum (GA) as the outer emulsifier. The physicochemical properties of bilayer emulsions were mainly characterized by droplet size distribution, zeta potential, rheological behavior, Creaming Index (CI), and encapsulation ratio of β-carotene. Besides this, the effects of processing conditions (pH, thermal treatment, UV radiation, strong oxidant) and storage time on the chemical stability of bilayer emulsions were also evaluated. The bilayer emulsion had a small droplet size (221.27 ± 5.17 nm) and distribution (PDI = 0.23 ± 0.02), strong zeta potential (-30.37 ± 0.71 mV), good rheological behavior (with the highest viscosity that could reduce the possibility of flocculation) and physical stability (CI = 0), high β-carotene encapsulation ratio (94.35 ± 0.71%), and low interfacial tension (40.81 ± 0.86 mN/m). It also obtained better chemical stability under different environmental stresses when compared with monolayer emulsions studied, because it had a dense and thick bilayer structure.

Emulsion design for the delivery of β-carotene in complex food systems

β-Carotene has been widely investigated both in the industry and academia, due to its unique bioactive attributes as an antioxidant and pro-vitamin A. Many attempts were made to design delivery systems for β-carotene to improve its dispersant state and chemical stability, and finally to enhance the functionality. Different types of oil-in-water emulsions were proved to be effective delivery systems for lipophilic bioactive ingredients, and intensive studies were performed on β-carotene emulsions in the last decade. Emulsions are thermodynamically unstable, and emulsions with intact structures are preferable in delivering β-carotene during processing and storage. β-Carotene in emulsions with smaller particle size has poor stability, and protein-type emulsifiers and additional antioxidants are effective in protecting β-carotene from degradation. Recent development in the design of protein-polyphenol conjugates has provided a novel approach to improve the stability of β-carotene emulsions. When β-carotene is consumed, its bioaccessibility is highly influenced by the digestion of lipids, and β-carotene in smaller oil droplets containing long-chain fatty acids has a higher bioaccessibility. In order to better deliver β-carotene in complex food products, some novel emulsions with tailor-made structures have been developed, e.g., multilayer emulsions, solid lipid particles, Pickering emulsions. This review summarizes the updated understanding of emulsion-based delivery systems for β-carotene, and how emulsions can be better designed to fulfill the benefits of β-carotene in functional foods.

Designing food delivery systems: challenges related to the in vitro methods employed to determine the fate of bioactives in the gut

This review discussesin vitroavailable approaches to study delivery and uptake of bioactive compounds and the associated challenges.

Effects of antioxidants on the stability of β-Carotene in O/W emulsions stabilized by Gum Arabic

The potential of oil-in-water emulsions as a β-carotene delivery system was examined in this study. Oil-in-water (O/W) emulsions containing β-carotene were formed by gum arabic with α-tocopherol, tertiary butyl hydroquinone (TBHQ) and ascorbyl palmitate, respectively. The influence of antioxidants on the chemical degradation of β-carotene in gum arabic stabilized emulsions was investigated at 4, 25, 45 and 65 °C in the dark, respectively. An accelerated photo-oxidation test was carried out at 45 °C (450 W/m(2)). Moreover, β-carotene degradation rate constants (k 1-value), activation energy (E a ) and decimal reduction time (D-value) were estimated to interpret the degradation kinetics. The impact of antioxidants on the thermal stability of β-carotene in diluted emulsions was generally in the following order: α-tocopherol > TBHQ > ascorbyl palmitate. α-Tocopherol was found to be the most effective to the antioxidation of β-carotene at the concentration of 0.10 wt% under light exposure. It was concluded that the stability of β-carotene in oil-in-water emulsions could be improved by the presence of different antioxidants.