Study of the Emulsifying Ability of Olive Oil Endogenous Compounds in Co-surfactant Free Olive Oil w/o Nanoemulsions with Food Grade Non-ionic Surfactants

Process Optimization of Tinospora cordifolia Extract-Loaded Water in Oil Nanoemulsion Developed by Ultrasound-Assisted Homogenization

Nanoemulsions are gaining interest in a variety of products as a means of integrating easily degradable bioactive compounds, preserving them from oxidation, and increasing their bioavailability. However, preparing stable emulsion compositions with the desired characteristics is a difficult task. The aim of this study was to encapsulate the Tinospora cordifolia aqueous extract (TCAE) into a water in oil (W/O) nanoemulsion and identify its critical process and formulation variables, like oil (27-29.4 mL), the surfactant concentration (0.6-3 mL), and sonication amplitude (40% to 100%), using response surface methodology (RSM). The responses of this formulation were studied with an analysis of the particle size (PS), free fatty acids (FFAs), and encapsulation efficiency (EE). In between, we have studied a fishbone diagram that was used to measure risk and preliminary research. The optimized condition for the formation of a stable nanoemulsion using quality by design was surfactant (2.43 mL), oil concentration (27.61 mL), and sonication amplitude (88.6%), providing a PS of 171.62 nm, FFA content of 0.86 meq/kg oil and viscosity of 0.597 Pa.s for the blank sample compared to the enriched TCAE nanoemulsion with a PS of 243.60 nm, FFA content of 0.27 meq/kg oil and viscosity of 0.22 Pa.s. The EE increases with increasing concentrations of TCAE, from 56.88% to 85.45%. The RSM response demonstrated that both composition variables had a considerable impact on the properties of the W/O nanoemulsion. Furthermore, after the storage time, the enriched TCAE nanoemulsion showed better stability over the blank nanoemulsion, specially the FFAs, and the blank increased from 0.142 to 1.22 meq/kg oil, while TCAE showed 0.266 to 0.82 meq/kg.

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.

Novel Processes for the Extraction of Phenolic Compounds from Olive Pomace and Their Protection by Encapsulation

Olive pomace, the solid by-product derived from olive oil production consists of a high concentration of bioactive compounds with antioxidant activity, such as phenolic compounds, and their recovery by applying innovative techniques is a great opportunity and challenge for the olive oil industry. This study aimed to point out a new approach for the integrated valorization of olive pomace by extracting the phenolic compounds and protecting them by encapsulation or incorporation in nanoemulsions. Innovative assisted extraction methods were evaluated such as microwave (MAE), homogenization (HAE), ultrasound (UAE), and high hydrostatic pressure (HHPAE) using various solvent systems including ethanol, methanol, and natural deep eutectic solvents (NADESs). The best extraction efficiency of phenolic compounds was achieved by using NADES as extraction solvent and in particular the mixture choline chloride-caffeic acid (CCA) and choline chloride-lactic acid (CLA); by HAE at 60 °C/12,000 rpm and UAE at 60 °C, the total phenolic content (TPC) of extracts was 34.08 mg gallic acid (GA)/g dw and 20.14 mg GA/g dw for CCA, and by MAE at 60 °C and HHPAE at 600 MPa/10 min, the TPC was 29.57 mg GA/g dw and 25.96 mg GA/g dw for CLA. HAE proved to be the best method for the extraction of phenolic compounds from olive pomace. Microencapsulation and nanoemulsion formulations were also reviewed for the protection of the phenolic compounds extracted from olive pomace. Both encapsulation techniques exhibited satisfactory results in terms of encapsulation stability. Thus, they can be proposed as an excellent technique to incorporate phenolic compounds into food products in order to enhance both their antioxidative stability and nutritional value.

Food-Grade Nanoemulsions for the Effective Delivery of β-Carotene

Utilization of β-carotene in functional food products is limited due to chemical instability, lower water-solubility, and higher melting point. The present research was designed to formulate a nanoemulsion system for the effective delivery of β-carotene. β-Carotene was successfully incorporated into nanoemulsions using the ultrasonication method. During 60 days of storage, the droplet size of β-carotene-containing nanoemulsions varied from 112.36 to 133.9 nm at 4 °C and from 112.36 to 147.1 nm at 25 °C. The oxidation stability of olive oil was remarkably increased when incorporated into nanoemulsions. β-Carotene nanoemulsions remained stable under varying ionic strengths (50-400 mM), pH values (2-8), and freeze-thaw cycles (four). The values of turbidity and total color difference increased over time and at a higher temperature. Degradation of β-carotene was substantially slower in nanoemulsions, and the addition of antioxidants significantly increased the retention of β-carotene in nanoemulsions. These findings suggest that the ultrasonic homogenization method has potential for the preparation of β-carotene nanoemulsions with desirable properties. These nanoemulsions can be effectively used for the incorporation of β-carotene in the food and beverage industry.

Tween 80 and Soya-Lecithin-Based Food-Grade Nanoemulsions for the Effective Delivery of Vitamin D

Fortification of food and beverages with vitamin D is demanding due to its poor water solubility and oxidation, due to exposure to light and high temperature. The purpose of this research work was to formulate an effective food-grade delivery system for the incorporation of vitamin D into food products and beverages. Food-grade vitamin D nanoemulsions were successfully prepared using mixed surfactant (Tween 80 and soya lecithin) and ultrasonic homogenization techniques. Significant effects (p < 0.05) of temperatures (4 and 25 °C) and storage intervals (1 month) were observed on the turbidity and vitamin D retention. At the end of a 2 month storage, the droplet sizes of the nanoemulsion were 140.15 nm at 4 °C and 155.5 nm at 25 °C. p-Anisidine value of canola oil significantly reduced (p < 0.05) after its incorporation into nanoemulsions. The turbidity values of nanoemulsions increased with the increase in storage duration and temperature. These nanoemulsions remain stable against a wide range of temperatures (30-90 °C), pH values (2-8), ionic strengths (50-400 mM), and freeze-thaw cycles (4 cycles). At the end of 30 days of storage, vitamin D retentions were 74.4 ± 1.2 and 55.3 ± 2.1% in nanoemulsions stored at 4 and 25 °C, respectively. These results suggest that mixed-surfactant-based nanoemulsions are an effective delivery system for the incorporation of vitamin D into food and beverages to overcome the worldwide deficiency of vitamin D.

Cow milk enriched with nanoencapsulated phenolic extract of jaboticaba (Plinia peruviana)

This study evaluated the total phenolic content (TPC) and the antioxidant activity (AA) of cow's milk enriched with phenolic compounds extracted from jaboticaba peel, either by adding jaboticaba crude extract or a jaboticaba-loaded nanoemulsion. Three nanoemulsions with 5, 10 and 15% of jaboticaba extract were prepared. Average particle diameter (166.7-181.7 nm), polydispersity index (0.138-0.156) and zeta potential (ranging from - 35.30 to - 38.60 mV) were measured for the three different colloidal systems. The nanoemulsion with 15% of jaboticaba extract (J15-NE) was chosen for milk enrichment. J15-NE showed an encapsulation efficiency of 85.6% and remained stable for 60 days at 8 °C. Transmission electron microscopy of J15-NE displayed nanoparticles with a well-defined spherical shape. Reference milk, milk enriched with jaboticaba extract and milk enriched with J15-NE were characterised by a TPC of 93, 171 and 161 µg/ml GAE (gallic acid equivalent), respectively, and an AA of 0.04, 0.17 and 0.14 µg/ml TEAC (trolox equivalent antioxidant capacity), respectively. Thus, this study showed that nanoemulsion with jaboticaba peel extract could be exploited as an ingredient to enrich the properties of milk.