جستجوی مقالات مرتبط با کلیدواژه "کارایی درون پوشانی" در نشریات گروه "صنایع غذایی"

Garlic extract, due to its high volatility and its effects on organoleptic properties, has limitations for direct use in food products, and therefore it is better to encapsulate it in one of the different methods and then use it in food formulations. In recent years, many methods have been used to encapsulate bioactive compounds in the food industry. Nanocapsulation can highly protect the essential oils against degradation or oxidation and may increase dispersibility in aqueous media, reduce adverse interaction with food components, and it generally do not affect antimicrobial activity of essential oils. Water-in-oil emulsions are used to encapsulate hydrophilic bioactive compounds, and the number of studies conducted on this type of emulsion is less than that of oil-in-water nanoemulsions. In this research, it has been tried to surrounding garlic extract by surfactant and forms a water in oil nanoemulsion and its physicochemical and antimicrobial properties are measured in order to be used in suitable food formulations.

In this study, nanoemulsions containing garlic extract were produced by high energy method (ultrasound bath) and the effect of different percentages of the extract on droplet size, antimicrobial properties, release kinetics, and viscosity were investigated. Encapsulation efficiency was determined by comparing the total area under the peaks of the nanoemulsions and not emulsified mixture headspace in gas chromatography. The release of volatile compounds of garlic oil was recorded during storage time by gas chromatography. Microdilution method was used to determine the minimum inhibitory concentration and the minimum bactericidal concentration. TGA and FT-IR were also used to evaluate the thermal resistance and to study the functional groups and to confirm the presence of the compounds used in the formulation of the prepared nanoemulsions, respectively.

Drop size varied from 62 to 302 nm for nanoemulsions based on volume fraction. Microbial results showed that water-in-oil nanoemulsions in high concentrations of garlic extract had antimicrobial properties and a stronger effect against gram-positive bacteria. In general, in all nano-emulsions, with increasing the volume fraction (percentage of garlic extract) from 5 to 25 %, the viscosity increased from 50 to 150 cp. Examination of viscosity changes at different temperatures showed that the activation energies for samples with different volume fractions (garlic extract) were not significantly different. Also, the release rate of volatiles increases with increasing volume fraction in nanoemulsion formulations and storage temperature.Keywords: Nanoemulsion, Garlic extract, Release kinetics, Encapsulation efficiency, Antimicrobial properties

As the demands for functional foods are on the rise, manufacturers have been seeking methods to use compound ingredients that make health promotion feasible. Nanoscience and nanotechnology have gained popularity in the 21st century. Scientists believe that nanotechnology can be used to handle matter at nano-dimensions. Nano powders, having a wide range of applications, were developed following the introduction of nanotechnology (Ananthu & Renjanadevi, 2016). It is believed that one the ways to save bioactive food ingredients from environmental damage and disguise their displeasure attributes is through encapsulation. Solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC) are the novel types of nanostructures; researchers argue that they are the novel colloidal sensitive carriers that can be used for scientific and industrial applications (Pardeike, Hommoss, & Muller, 2009). Traditionally, the Mediterranean diet has been consisted of olive tree (Olea europaea) products that led to decreased risk of chronic diseases such as cardiovascular diseases and several cancers. Phenolic acids, phenolic alcohols, flavonoids, and secoiridoids are the usual phenolic compounds found in olives. Olives are rich in oleuropein, demethyloleuropein, and ligstroside (Yoon, 2018). Several pharmacological features have been reported in oleuropein such as antioxidant (Visioli, Poli, & Galli, 2002), anti-inflammatory (Visioli, Bellosta, & Galli, 1998), anti-atherogenic (Carluccio et al., 2003), anti-cancer (Owen et al., 2000), antimicrobial (Tripoli et al., 2005), and antiviral ones (Fredrickson & Group, 2000); hence, it has been used commercially as food supplement in Mediterranean countries. Besides, research shows that oleuropein exerts cardio-protective effect against acute adriamycin cardiotoxicity (Andreadou et al., 2007); it was also reported that they are involved in anti-ischemic and hypolipidemic activities (Andreadou et al., 2006). Oleuropin is the most abundant type of phenolic compounds in olive leaf and its therapeutic effects are well known as a potent antioxidant. Extraction of oleuropein from olive leaves as a rich source of this compound is very valuable. On the other hand, the encapsulation efficiency of this compound is an effective way to maintain its characteristics during storage. The present research tried to investigate the synthesis method, characterization, and physical stability of nanostructured lipid carrier containing of olive leave extract. Various methods including high mechanical shear, high-pressure melt-homogenization method can be applied to synthesize the novel nanoencapsulation system (NLC). Since data on the effects of formulation compound on physicochemical properties of oleuropein-loaded NLC is scarce, the present research attempted to study the effect of concentrations of solid and liquid lipid, surfactant and olive leaf extract powder on physical and chemical characteristics of oleuropein-NLC by the application of one-at-time method. Initial component concentrations were chosen by the Design Expert Software (version 7.0.0) and one-factor-at-a-time method/one-variable-at-a-time method at various levels. In a study an extract containing oleuropein, was extracted from olive leaves, was prepared in the form of lipid nanocarriers. Extraction was performed by combining solvents ethanol: water (70:30) in a warm bath (40 °C for 30 minutes) using an HPLC apparatus. By designing 15 formulas for the nano-structured lipid carrier, the particle size and encapsulation efficiency were determined by a zeta sizer and HPLC, respectively. After determining the optimal formulation, zeta potential was also evaluated using a zeta sizer. The results showed that the extraction method of oleuropein from olive leaf with ethanol and water (70:30) contained 221.37 mg/g of oleuropein with a purity of oleuropein 137.22. The large amount of olive leaf extract in extraction with ethanol could be due to the better solubility of the active compounds (polyphenols) in organic solvents, such as ethanol. Result is showed the average particle size for all freshly produced oleuropein-loaded NLC formulations with diameters of ~0.10±0.00 and 5767± 640.15 nm. Also, the results of the dynamic light scattering test showed that the optimal formulation had a mean particle size of 12.19 nm, a scattering index of 0.153, a zeta potential of -43.3-millivolt. The negative loads on the surface of nano-carriers were probably due to the presence of lipophilic surfactants with negative load (lecithin) and free fatty acids (linoleic acid and linolenic acid, oleic acid, and free fatty acids in soybean oil). Probably the hydroxyl group in the encapsulant (oleuropein) has a hydrogen bond with a choline group in the polar head of the phosphatidylcholine and the choline group with the positive load is pulled inside and the phosphatidyl group with negative load is driven to the membrane surface. Therefore, the negative load of the nano-carriers is increased, which leads to electrostatic disposal of particles and, finally, stability of these particles. Microencapsulation values of nano-carriers varied from 1.27 ± 0.10 to 82 ± 0.41 and the formula with code 12 had the highest efficiency of microencapsulation. Adding liquid lipid to the lipid mixture and increasing the liquid part to solid part ratio resulted in the formation of a more amorphous state and less crystalline state of the nano-carriers and, finally, led to the defective and increased encapsulation material in nano-carriers (increased efficiency of microencapsulation). This could be probably due to more solubility of the encapsulation material in the liquid part of the lipid. Finally, the results of the encapsulation efficiency showed that the nano-carrier had 82% of the overlapping oleuropein. One of the aims of the application of nanocarriers in the food industry is to improve bioavailability, cover the undesirable odor, flavor, color, and improve solubility of some materials. Results of this work depicted that adding nanocarriers containing olive leaf extract powder as the source rich of oleuropein to the food, such as sauce, could improve the undesirable appearance, color, odor and flavor of the extract powder (polyphenols such as oleuropein) and also enjoy high durability of antioxidant properties of the polyphenols existing in the nanocarrier. A practical opinion/idea is that encapsulation of olive leaf extract powder as nutraceutical component can be applied to nutritive and pharmaceutical industries as well as production high quality products with whiteness, uniformity/homogeneity, appropriate flowability and flavor properties. Finally, the nano carrier with the lowest olive leaf extract powder, had the highest encapsulation efficiency, the lowest dispersity index and particle size.

In this research, in order to cover the smell of garlic, various formulations of garlic essential oil nanoemulsions were prepared by high energy method (water bath type ultrasound) and the effects of garlic essential oil percent and oil type on droplet size, encapsulation efficiency, anti-oxidative capacity and turbidity of nanoemulsions were studied. The droplet size of dispersed phase ranged from 80 to 100 nm based on dispersed phase ratio. The obtained results from gas chromatography showed that the prepared nanoemulsions have covered the volatile components of garlic essential oil but encapsulation efficiency was decreased from 92 to 77% by increasing dispersed phase (essential oil of garlic) from 5 to 25%. Also, the effect of garlic essential oil percent was significant on droplet size, encapsulation efficiency, anti-oxidative capacity and turbidity of nanoemulsions. Droplet size, anti-oxidative capacity and turbidity were increased while encapsulation efficiency was decreased by increasing essential oil percent.