Preparation and characterization of water-in-oil emulsions loaded with high concentration of l-ascorbic acid

Rheology and Extrusion Printing of κ-Carrageenan/Olive Oil Emulsion Gel Tablets with Varying Surface Area to Volume Ratios for Release of Vitamin C and Curcumin

In this work, κ-carrageenan and olive oil at different oil to κ-carrageenan ratios (OCR) are homogenized to create emulsion gels. Interestingly, confocal imaging shows that the oil droplets are stabilized in the κ-carrageenan-structured gel matrix without using any surfactants. Rheological studies show that the oil droplets enhanced the oscillatory yield stress and the maximum printable height of the emulsion gels. The creation of the emulsion gels with an OCR of 1:9-3:7 led to an improvement in the structural integrity of extrusion printed structures. The emulsion gel with an OCR of 3:7 efficiently encapsulates vitamin C in the aqueous phase and curcumin in the hydrophobic oil phase, enabling the extrusion 3D printing of tablets with varying surface area to volume (SA/V) ratios. The release of vitamin C and curcumin is influenced by the preparation method of printing versus casting and the SA/V ratio of the tablets. The hollow cylinder with the highest SA/V ratio was observed to have the highest vitamin C release, whereas for curcumin, the printed tablets had a higher release compared to the cast tablet. Additionally, through rheo-dissolution experiments, we observe a lower modulus and higher vitamin C release from the 3D-printed disc versus the higher modulus and lower vitamin C release from the cast disc tablet.

Formulation of Chicken Nuggets Supplemented with Mutton and Fish Livers: Insights from Antioxidant and Textural Studies

The use of byproducts from the food industry and the investigation of substitute sources are becoming progressively significant in fulfilling the consumer demand for animal-based protein. This study aimed to investigate the nutritional value of mutton and fish livers and their future application as a source of high-added-value proteins for supplement formulation. We performed compositional analysis (moisture, ash, crude protein, crude fat), free fatty acid (FFA) analysis, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the color, peroxide value (POV), and total phenolic composition (TPC) were assessed to evaluate the nutritional value and shelf stability of mutton and fish livers. The optimized proximate and kinetics were later used to develop chicken nuggets with different percentages of mutton and fish liver added. The formulation was tested for the textural and organoleptic properties of value-added chicken nuggets that predict consumer acceptability. Comparative analysis of the variance between mutton and fish liver showed a highly significant (P<0.01) decrease in moisture, ash, protein, fat, DPPH, and TPC at different days and hours. The mutton liver had relatively high antioxidant potential (25.9% DPPH and 154-mg GAE/100 g TPC) compared with the fish liver. However, the fish liver's FFA and POV (2.4% for both) were higher than those of the mutton liver. The results showed that, after formulation, an increase in the amount of liver led to a highly significant (P<0.01) rise in the nutritional value of the nuggets, including a 1.5%∼2.0% increase in protein content. This research indicates that valuing mutton and fish liver as a protein replacer in processed foods can be useful in developing healthy food products.

Development of Emulsions Containing L-Ascorbic Acid and α-Tocopherol Based on the Polysaccharide FucoPol: Stability Evaluation and Rheological and Texture Assessment

The main function of vitamin C, as an antioxidant, is to combat free radicals and prevent premature aging, smoothing wrinkles and expression lines. In addition, it acts directly on depigmentation and prevention of blemishes on the skin. In this study, natural oils (30 wt.%) and α-tocopherol (2.5 wt.%) containing oil-in-water (O/W) emulsions stabilized with the bacterial fucose-rich polysaccharide FucoPol were formulated, adding L-ascorbic acid as an antioxidant. The optimized formulations were obtained with 8.0 wt.% L-ascorbic acid for the Olea europaea oil formulation (C1) with a ƞ value of 2.71 Pa.s (measured at shear rate of 2.3 s−1) and E24 = 96% and with 15 wt.% L-ascorbic acid for the Prunus amygdalus dulcis formulation (C2) with a ƞ value of 5.15 Pa.s (at a shear rate of 2.3 s−1) and E24 = 99%. The stability of the FucoPol-based formulations was investigated over 45 days at 4 °C, 20 °C, and 30 °C. The results showed that all formulations maintained the organoleptic characteristics, with pH variations (5.7–6.8 for C1, and 5.5–6.03 for C2) within the regulations for cosmetic products (4 ≤ pH ≤ 7). The accelerated stability tests proved the formulations’ stability at 4 °C with EI = 95% for C1 and EI = 100% for C2. The rheological assessment demonstrated that the formulation presents a shear-thinning and liquid-like behavior. Regarding textural parameters, formulations C1 and C2 displayed an increase in firmness and consistency with similar spreadability during the shelf life. These findings further demonstrate FucoPol’s functional properties, acting as an emulsifier and stabilizer polysaccharide in cosmetic formulations containing L-ascorbic acid.

Physicochemical Characteristics of Mixed Surfactant-Stabilized l-Ascorbic Acid Nanoemulsions during Storage

The incorporation of l-ascorbic acid into food products is challenging for food industries due to its chemical instability. This study was conducted to develop a nanoemulsion-based effective colloidal system for the incorporation of l-ascorbic acid (LAA) in functional food products. l-ascorbic acid was encapsulated in nanoemulsions prepared through high-pressure homogenization. The physicochemical characteristics of mixed-surfactant-based LAA nanoemulsions were investigated during storage at different temperatures. The droplet size of LAA nanoemulsions after one month of storage varied in the range of 121.36-150.15 and 121.36-138.25 nm at 25 and 4 °C, respectively. These nanoemulsions remained stable against processing conditions such as heat treatments (10-70 °C), different salt concentrations (40-320 mM), change in pH (3-9), and four freeze-thaw cycles. The temperature and storage intervals have a significant (p < 0.05) effect on the retention of LAA in nanoemulsion-based delivery systems. The findings of this research work have important implications in the designing and preparation of an effective encapsulation system for the inclusion of l-ascorbic acid into functional food products.

Chemical Stability of Ascorbic Acid Integrated into Commercial Products: A Review on Bioactivity and Delivery Technology

The L-enantiomer of ascorbic acid is commonly known as vitamin C. It is an indispensable nutrient and plays a key role in retaining the physiological process of humans and animals. L-gulonolactone oxidase, the key enzyme for the de novo synthesis of ascorbic acid, is lacking in some mammals including humans. The functionality of ascorbic acid has prompted the development of foods fortified with this vitamin. As a natural antioxidant, it is expected to protect the sensory and nutritional characteristics of the food. It is thus important to know the degradation of ascorbic acid in the food matrix and its interaction with coexisting components. The biggest challenge in the utilization of ascorbic acid is maintaining its stability and improving its delivery to the active site. The review also includes the current strategies for stabilizing ascorbic acid and the commercial applications of ascorbic acid.

Optimisation of food grade mixed surfactant-based l-ascorbic acid nanoemulsions using response surface methodology

Co‐surfactant free l‐ascorbic acid (LAA) nanoemulsions were prepared using mixed surfactants (Soya lecithin and Tween 80). Response surface methodology (RSM) was used to optimise the emulsifying conditions for LAA nanoemulsions. The effects of water proportion (6%–14% w/w), homogenisation pressure (80–160 MPa), surfactant concentrations (4%–12% w/w) and laa concentration (0.5–1.3 w/w) on responses (size of droplets and nanoemulsion stability) were investigated. RSM results showed that the values of responses can be successfully predicted through second‐order polynomial model. The coefficients of determinations for droplet size and nanoemulsion stability were 0.9375 and 0.9027, respectively. The optimum preparation conditions for l‐LAA nanoemulsion were 9.04% water proportion, 114.48 MPa homogenisation pressure, 7.36% surfactant concentration and 1.09% LAA concentration. At the end of one month storage study, the retention of LAA in optimised nanoemulsions stored at 4°C and 25°C were 74.4% and 66.7%, respectively. These results may provide valuable contributions for food and pharmaceutical industry to develop delivery system for food additives and nutraceutical components.

Ultrasonic assisted water-in-oil emulsions encapsulating macro-molecular polysaccharide chitosan: Influence of molecular properties, emulsion viscosity and their stability

An ultrasonic technique was applied to formulation of two-phase water-in-paraffin oil emulsions loading a high-molecular polysaccharide chitosan (CS) and stabilized by an oil-soluble surfactant (Span80) at different operational conditions. The influence of chitosan molecular properties, phase volume ratio (φ_w), Span80 volume fraction (φ_s) and ultrasonic processing parameters were systemically investigated on the basis of mean droplet diameter (MDD) and polydispersity index (PDI) of emulsions. It was observed that the molecular weight (M_w) of CS was an important influential factor to MDD due to the non-Newtonian properties of CS solution varying with M_w. The minimum MDD of 198.5 nm with PDI of 0.326 was obtained with ultrasonic amplitude of 32% for 15 min at an optimum φ_w of 35%, φ_s of 8%, probe position of 2.2 cm to the top of emulsion, while CS with M_w of 400 kDa and deacetylation degree of 84.6% was used. The rise of emulsion viscosity and the reduction of negative zeta potential at φ_w increasing from 5% to 35% were beneficial to obtain finer droplets and more uniform distribution of emulsions, and emulsion viscosity could be represented as a monotonically-decreasing power function of MDD at the same φ_w. FTIR analysis indicated that the molecular structure of paraffin oil was unaffected during ultrasonication. Moreover, the emulsions exhibited a good stability at 4 °C with a slight phase separation at 25 °C after 24 h of storage. By analyzing the evolution of MDD, PDI and sedimentation index (SI) with time, coalescence model showed better fitting results as comparison to Ostwald ripening model, which demonstrated that the coalescence or flocculation was the dominant destabilizing mechanism for such W/O emulsions encapsulating CS. This study may provide a valuable contribution for the application of a non-Newtonian macromolecule solution as dispersed phase to generate nano-size W/O emulsions via ultrasound, and widen knowledge and interest of such emulsions in the functional biomaterial field.

Nano- and micro-particles for delivery of catechins: Physical and biological performance

Catechins, present in many fruits and vegetables, have many health benefits, but they are prone to degradation. Nano- and micro-particle systems have been used to stabilise catechins when exposed to adverse environments and to improve their bioavailability after ingestion. This review discusses the inherent properties of various catechins, the design of delivery formulations and the properties of catechin-loaded nano- and micro-particles. The protection afforded to catechins during exposure to harsh environmental conditions and gastrointestinal tract transit is reviewed. The bioavailability and efficacy of encapsulated catechins, as assessed by various in vitro and in vivo conditions, are discussed. Bioavailability based on uptake in the upper gut alone underestimates the bioavailability as polyphenols. The caveats with interpretation of bioavailability based on various tests are discussed, when taking into consideration the pathways of catechin metabolism including the role of the gut microflora. However, taken together, the weight of the evidence suggests that there are potentially improved health benefits with the use of appropriately designed nano- and micro-particles for delivery of catechins. Further systematic studies on the metabolism and physiological effects of encapsulated catechins in vivo and clinical trials are needed to validate the bioefficacy of the encapsulated catechins.

Monodisperse aqueous microspheres encapsulating high concentration of l-ascorbic acid: insights of preparation and stability evaluation from straight-through microchannel emulsification

Stabilization of l-ascorbic acid (l-AA) is a challenging task for food and pharmaceutical industries. The study was conducted to prepare monodisperse aqueous microspheres containing enhanced concentrations of l-AA by using microchannel emulsification (MCE). The asymmetric straight-through microchannel (MC) array used here constitutes 11 × 104 μm microslots connected to a 10 μm circular microholes. 5–30% (w/w) l-AA was added to a Milli-Q water solution containing 2% (w/w) sodium alginate and 1% (w/w) magnesium sulfate, while the continuous phase constitutes 5% (w/w) tetraglycerol condensed ricinoleate in water-saturated decane. Monodisperse aqueous microspheres with average diameters (dav) of 18.7–20.7 μm and coefficients of variation (CVs) below 6% were successfully prepared via MCE regardless of the l-AA concentrations applied. The collected microspheres were physically stable in terms of their dav and CV for &gt;10 days of storage at 40°C. The aqueous microspheres exhibited l-AA encapsulation efficiency exceeding 70% during the storage.