Food Chemistry
Negin Jafarian; Afshin Akhondzadeh Basti; Hamideh Emtiazi
Abstract
Background and Objectives Natural preservatives extracted from herbs are important sources for bioactive compounds that can be used in protection of food products. Essential oils are aromatic oily liquids, obtained from plant material like flowers, buds, seeds, leaves, and roots. Unfortunately, ...
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Background and Objectives Natural preservatives extracted from herbs are important sources for bioactive compounds that can be used in protection of food products. Essential oils are aromatic oily liquids, obtained from plant material like flowers, buds, seeds, leaves, and roots. Unfortunately, most natural compounds are biologically instable, poorly soluble in water and they distribute poorly to target sites. Currently, some novel methods have been introduced in order to improve their stability and their bioavailability, among which is the use of liposomal encapsulation. Microencapsulation reduces reactivity with the environment (water, oxygen, light), decreases the evaporation or the transfer rate to the outside environment, promotes handling ability, masks taste and enhances dilution to achieve a uniform distribution in the final product when used in very small amounts. Essential oils, as natural extracted compounds extracted from plants, are unstable compounds with low water solubility and unable to achieve target cells. Essential oils encapsulation by nanoliposomes is a novel method for increasing their biological activity and protecting them from destructive factors. The aim of this study was production and optimization of nanoliposomes containing Z. teniur essential oil and investigating their antibacterial effects against pathogens (Staphylococcus aureus and Escherichia coli). Materials and Methods Lipid film hydration method was used to produce nanoliposomes containing Z. teniur essential oil. Soy phosphatidylcholine and cholesterol were the main wall materials and chloroform was used as the mixing solvent . The particle size of nanoliposomes and their zeta-potential were investigated using laser diffraction method. In order to determine the minimum inhibitory concentration and the minimum bactericidal concentration of Z. teniur essential oil against examined bacteria, serial dilution method was used. Also, antioxidant activity of free and nano-encapsulated essential oil of Z. teniur was determined by DPPH method. Results According to the results, highest encapsulation efficiency achieved by using 80:20 ratio of soy phosphatidylcholine to cholesterol in nanoliposomes’ wall structures. In general, by increasing the ratio of phosphatidylcholine to cholesterol, encapsulation efficiency was improved. Zeta-potential of nanoliposomes was equal to -5.3 mv and mean particle sizes were in the range of 94.7-119.9 nm. Results indicated that essential oil ejection from nanoliposomes has direct relation to the time of storage and after 30 hours, ejection rate will increase considerably. Ejection rate was higher in phosphate buffer pH=7.4 in comparison with phosphate buffer pH=5.4. Minimum inhibitory concentration and minimum bactericidal concentration of free essential oil against Escherichia coli was 100 and 175 (µl/ml) respectively. Although, Minimum inhibitory concentration and minimum bactericidal concentration of nanoliposomes containing Z. teniur essential oil were equal to 75 and 150 (µl/ml) respectively. Also, results shown that , minimum inhibitory concentration and minimum bactericidal concentration of encapsulated Z. teniur essential oil against Staphylococcus aureus were lower in comparison with free form of Z. teniur essential oil. Staphylococcus aureus (as Gram-positive bacteria) was more susceptible than Escherichia coli (as Gram-negative bacteria). Conclusion Encapsulation of Z. teniur essential oil by nanoliposomes led to improve antibacterial effects of essential oil against Staphylococcus aureus and Escherichia coli. Also, investigating of antioxidant activity showed that encapsulated Z. teniur essential oil in nanoliposomes was more effective than free form of Z. teniur essential oil in scavenging of DPPH free radicals. Using nanoliposome encapsulation technology can be an effective way for increasing the efficiency of natural antibacterial compounds and essential oils encapsulated in nanoliposomes are suitable alternatives for synthetic preservatives used in food industry nowadays. The use of liposomes containing Z. teniur essential oil can provide the necessary protection against growth of spoilage and pathogenic microorganisms such as Staphylococcus aureus and Escherichia coli in food products.
Food Technology
Masoumeh Salamatian; Younes Zahedi; Rezvan Shaddel
Abstract
Introduction
Capparis spinosa is a perennial herb from the Capparidaceae family that is mainly distributed in arid and semi-arid regions. Its fruits are oval shaped, approximately 3 cm long, greenish in color with red pulp. Capparis spinosa extract is a rich source of phenolic compounds. The instability ...
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Introduction
Capparis spinosa is a perennial herb from the Capparidaceae family that is mainly distributed in arid and semi-arid regions. Its fruits are oval shaped, approximately 3 cm long, greenish in color with red pulp. Capparis spinosa extract is a rich source of phenolic compounds. The instability of phenolic compounds in the environmental conditions as well as their bitter or astringent taste has created challenges for the use of these compounds in the food industry. Encapsulation is a method that can positively affect bioaccessibility and bioavailability as it ensures the coating of the active component and its targeted delivery to a specific part of the digestive tract and controlled release. Encapsulation using nanoliposomes seems to be an appropriate technique to overcome these issues. Nanoliposomes are the nanometric version of liposomes. Liposomes are spherical particles composed of lipid molecules (mainly phospholipids) that tend to accumulate in polar solvents such as water in the form of bilayer membranes. Encapsulation with liposomes is an effective way to preserve the intrinsic properties of bioactive compounds during storage and production of foods fortified with them, as well as a physicochemical barrier against prooxidant agents such as free radicals, oxygen and UV.
Materials and Methods
Materials: Capparis spinosa fruits, were collected from subtropical regions of Ilam province (Iran). Folin ciocalteu, gallic acid and tween 80 from Merck (Germany), cholesterol and phosphatidylcholine from Sigma- Aldrich (Germany) were obtained.
Methods: The extract was obtained from capparis spinosa fruit powder using ultrasonic bath (Backer, vCLEAN 1- L6, Iran). The phenolic content was measured by folin ciocalteu method. Nanoliposomes containing capparis spinosa extract were prepared in ratios of 60- 0, 50- 10, 40- 20 and 30- 30 w/w lecithin- cholesterol. Then, particle size, PI and zeta potential were measured by DLS (Horiba, Japan) at 25 oC. After calculating the encapsulation efficiency using its corresponding equation, the investigation of possible reactions between capparis spinosa extract and phospholipids was performed using FTIR at a frequency of 400- 4000 cm-1. In order to observe shape and morphology of nanoliposomes loaded with capparis spinosa extract by field emission scanning electron microscopy (FESEM), a drop of sample was poured on the laboratory slide, dried at ambient temperature and then, the sample was coated with gold layer using an ion sputtering device. The stability of the samples was evaluated by visual observation of phase separation and the release rate of phenolic compounds encapsulated in nanoliposomes at ambient temperature over a period of 60 days.
Results and Discussion
The amount of phenolic extract was 6.328 mg of GAE/g dry sample. The average particle size (Z- Average) was in the range of 95.05 to 164.25 nm. Increasing the cholesterol concentration resulted in enhancement of particle size of nanoliposomes. The particle size distribution was in an acceptable range of 0.3 to 0.5 (PI 0.5). The PI of the cholesterol-free nanoliposomes was maximum and significantly higher than that of the others. Addition of cholesterol increased zeta potential from -60.40 to -68.55. Higher zeta potential values indicate a higher and long term stability of the particles. Also, cholesterol led to an increase of encapsulation efficiency (EE). The stability of phenolic compounds loaded in nanoliposomes was affected by cholesterol during storage time via reducing fluidity and permeability of liposomal membrane. Presence of cholesterol also inhibited the membrane rupture and any changes into it. Results of FTIR showed interactions between wall constituents of nanoliposome and capparis spinosa extract, and confirmed successful loading of the extract within nanoliposomes. Images of FESEM were in agreement with DLS results regarding particle size and particle size distribution.
Conclusion
This study indicate that the nanoliposomes have potential applications in improvement of the shelf life of nutraceuticals, stability of cosmetic materials and drug delivery systems. The phenolic compounds of encapsulated extract showed good stability within two months of storage at room temperature. The results showed that the problem of instability of phenolic compounds, which leads to their limited commercial application, can be solved by encapsulation.
Soheyl Reyhani Poul; Sakineh Yeganeh; Reza Safari
Abstract
[1]Introduction: Nisin is one of the antimicrobial substances that is used today as a preservative in various foodstuffs. It is a bacteriocin comprised of 34 amino acids and a molecular weight of 3.5 Da. With all the benefits of nisin, there are barriers to its use in dairy and protein rich products. ...
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[1]Introduction: Nisin is one of the antimicrobial substances that is used today as a preservative in various foodstuffs. It is a bacteriocin comprised of 34 amino acids and a molecular weight of 3.5 Da. With all the benefits of nisin, there are barriers to its use in dairy and protein rich products. One of these barriers is the combination of nisin with fats, proteins and sugars and the consequent reduction of its antibacterial activity. In the food science and industry, the use of the technique of encapsulation and production of liposome is the best possible solution in such cases. Also, by adding an antimicrobial agent such as chitosan to the coating of nanoliposomes, the antibacterial activity of the product may be increased. The aim of the present research was to produce nanoliposomes carrying nisin with (and without) chitosan coating and to evaluate the physical and antibacterial properties against two gram-positive bacteria, Bacillus cereus and Staphylococcus aureus. Materials and Methods: In this study, four treatments of nanoliposomes carrying nisin (NN), nanoliposomes carrying nisin coated with chitosan 0.05% ((NN-CH (0.05)), nanoliposomes carrying nisin coated with chitosan 0.1% (NN-CH (0.1)) and nanoliposomes carrying nisin coated with chitosan 0.5% (NN-CH (0.5)) were prepared and examined in terms of physical properties (average particle size, particle dispersity index, zeta potential and encapsulation efficiency) and antibacterial activity (against two gram-positive bacteria, Bacillus cereus and Staphylococcus aureus with two diffusion methods in agar medium and microdilution test). This research was conducted in a completely randomized design and SPSS and EXCEL softwares were used for statistical analysis and drawing of diagram, respectively. Data were analyzed by one-way analysis of variance and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and Discussion: The results showed that the average particle sizein different treatments with each other are significantly different (P<0.05) and vary from about 110 to 327nm; Also as the amount of chitosan in the coating increased, the particle size increased (P<0.05). This indicates the successful binding of chitosan to the surface of the nanoliposome, which results in the formation of a layer around the nanoliposome and an increase in particle size. Particle dispersity index was recorded less than 0.3 in all treatments and was not related to the amount of chitosan in the coating. With increasing the amount of chitosan in the coating of nanoliposomes, zeta potential increased significantly (P<0.05). This index changed from -55.34 in NN treatment to 53.14 mV in NN-CH (0.5) treatment. In fact, chitosan as a cationic polysaccharide changes the potential to positive values. As the amount of chitosan in coating of nanoliposomes increased, the encapsulation efficiency increased significantly in the treatments (P<0.05); this index increased from 32.19% in NN treatment to 75.14% in NN-CH (0.5) treatment. The results of the antibacterial activity of nisin in two methods of diffusion in agar medium and microdilution test showed that its antibacterial activity increased with nanoencapsulation of nisin with (and without) chitosan coating (p<0.05). Also, with the increase in chitosan concentration, the antibacterial activity of carrier nanoliposomes increased and the highest antibacterial activity was recorded in NN-CH (0.5) treatment (p<0.05). The diameter of the non-growth halo of Bacillus cereus against the research treatments (with five concentrations of 2.5 to 25 μg/ml) varied from about 4.5 to 17.5 mm. This amount for Staphylococcus aureus was recorded from 2.1 to 26.5 mm. By increasing the concentration of nisin and carrier nanoliposomes, the diameter of the halo of non-growth of both bacteria increased significantly (p<0.05). But an exception was recorded in this case; The diameter of the non-growth halo for Staphylococcus aureus in two concentrations of 2.5 and 5 μg/ml of treatments was the same and had no significant difference (p>0.05). The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the examined treatments for Bacillus cereus were in the range of 100 to 400 and 200 to 500 μg/ml, respectively. These two concentrations for Staphylococcus aureus were recorded as 50 to 200 and 100 to 400 μg/ml respectively. Based on the values of diameter of non-growth halo, MIC and MBC it can be claimed that Bacillus cereus is more resistant to the examined treatments than Staphylococcus aureus.Nanoencapsulation of nisin in the form of carrier nanoliposomes with chitosan coating is a suitable solution to improve its physical and antibacterial properties. In such a way that by increasing the concentration of chitosan in the coating, both of the aforementioned properties improved significantly. Nanoliposomes carrying nisin with (and without) chitosan coating have the ability to inhibit the growth and killing Bacillus cereus and Staphylococcus aureus bacteria. The antibacterial activity increases with the increase in nisin and carrier nanoliposomes concentrations. The value of non-growth halo, minimum inhibitory concentration and minimum bactericidal concentration confirm that Bacillus cereus is more resistant to nisin and its carrier nanoliposomes than Staphylococcus aureus.
Babak Ghanbarzadeh; Akram Pezeshki; Hamed Hamishekar; Mohammad Moghaddam
Abstract
Introduction: The encapsulation of hydrophobic nutraceutical compounds such as fat soluble vitamins in nanoliposomes is a potentially effective way to protect them from from light, oxygen and chemical degradation during the maintenance. One of the potential benefits of liposomal structures is encapsulation ...
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Introduction: The encapsulation of hydrophobic nutraceutical compounds such as fat soluble vitamins in nanoliposomes is a potentially effective way to protect them from from light, oxygen and chemical degradation during the maintenance. One of the potential benefits of liposomal structures is encapsulation of three water-soluble, fat-soluble and amphiphilic compounds and use of natural food ingredients such as lecithin with beneficial effects, in their production. In this study, the effect of lecithin-cholesterol concentrations on particle size, particle size distribution, encapsulation efficiency (EE) and physical stability of vitamin A palmitate loaded nanoliposome during the storage time were explored to get the optimized formulationMaterials and method:Materials: Phospholipid (L-α-granular Lecithin) with purity of 99% was obtained from Across (USA). Cholesterol with 95% purity was supplied by Merck (Germany). Other chemicals were analytical grade and procured from Sigma (Merck Chemical Co. Darmstadt, Germany).Methods:Nanoliposomes were prepared from different concentrations of lecithin–cholesterol (60:0, 50:10, 40:20 and 30:30 mg) by thin-film hydration–sonication method. Lecithin and cholesterol were dissolved in absolute ethanol and then dried with vacuum evaporator. Prepared dried lipid film hydrated by aqueous phase. The resultant suspension was mixed for some time (Hydration-dehydration). Due to existence of water inside the lipid film, osmotic pressure runs the water into bilayer membrane and causes separation of lipid film and then liposomes were produced. In this method, mixture of Multilamellar Vesicles (MLVs) and Small Unilamellar Vesicles (SUVs) liposomes were produced. Reduction in particle sizes of prepared liposomes was done by ultra sound probe sonicator. The average diameter and span value of the particles were determined using particle size analyzer (Wing SALD 2101, Shimadzo, Japan), at 25°C and was calculated according to the DeBroukere mean in the Equation (1):The span value is an index helpful to evaluate the particle size distribution and calculated applying the following Equation: Morphology of the nano-carriers was observed using trans- mission electron microscopy (Zeiss-Leo 906 TEM (Germany). To determine the zeta potential of nano liposomes loaded vitamin A, Zeta siyzer device (Nano-ZS -Malvern England) was used at 25◦C temperature. Estimation of encapsulated vitamin in nanoliposomes (%EE) was carried out using HPLC (Knauer,Germany) equipped with a UV detector, C-18(10 mm 25mm_4.6 mm) column and acetonitrile– methanol (70:30%,v/v) as mobile phase and was calculated using the below equation%EE= (Encapsulated Vitamin A)/(Total Vitamin A) ×100The stability of vitaminA loaded-nanoliposomes was assessed by determining the average particle size at 4 °C over storage time and studying the leak out of the vitamin from the nanoliposomes after one month(1,7, 15and 30days)of storage at 4 °C by the below equation%Stability = (Remained Vitamin A)/(Initial encapsulated Vitamin A) ×100Results and Discussion: Results showed use of sonication in completion thin-film hydration method, induced production of monomodular nanoliposomes with uniform distribution The particle size was in the range of 76-115nm and particle size distribution was monomodular (span= 0.6- 0.88). In agreement with particle size results, TEM image showed that the vesicles are in the form of small unilamellar vesicles by bilayer nature. In all concentrations of lecithin-cholesterol, obtained EE was low and by increasing the lecithin concentration, loading capacity of nano liposomes increased. By increasing the lecithin concentration, more vesicles are produced which causes increase in internal volume of liposomes and bio actives concentrate, consequently loading capacity of nano liposomes increased. By tightening of the membrane by cholesterol, entrapment efficiency of hydrophobic active compounds such as vitamin A palmitate reduces. Also probably existence of cholesterol in liposome membrane inhibits of rupture and changes in liposome membrane. Overall, increasing the ratio of cholesterol /lecithin had no significant effect on particle size but decreased encapsulation efficiency of vitamin A palmitate to 10.23%. Addition of cholesterol effected on stability of the particle size of nanoliposomes and also led to reduction encapsulation efficiency of vitamin A palmitate. Incorporation of cholesterol and vitamin A palmitate into the liposome structure was increased the zeta potential from -29 to -58 mv and improved electrostatic stability. 50-10 mg ratio of lecithin-cholesterol concentration was used for preparation of optimum formulation of nanoliposome by monomodular and small size distribution (76 nm, span=0.74) and encapsulation efficiency (15.8%). Stability of vitamin A in nano liposome with 50-10 mg lecithin-cholesterol, was almost low (32% reduction during storage time), may be due to increasing fluidity of membrane. Permeability of vitamin A into phospholipid chains causes reorientation of acyl chains which leads to fluidity of membrane and exit active compound from nano carrier and more its hydrolytic degradation and oxidation. While the use of thin film hydration method using ultrasonic waves, is successful way in producing nanoscale particles of vitamin A palmitate nanoliposomes that are stable and decrease over time, but due to low efficiency and low sustainability of encapsulation, use of other nanocarriers for encapsulating of vitamin A palmitate is recommended
Zahra Mohammad Hassani; Babak Ghanbarzadeh; Hamed Hamishekar; Reza Rezaeemokaram
Abstract
Utilization of non-food-grade organic solvents and high shear forces in conventional liposome formation techniques has limited their applications as carriers of nutrecuticals in food industry. The objective of this research is the production of gamma-oryzanol bearing nanoliposome by using modified thermal ...
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Utilization of non-food-grade organic solvents and high shear forces in conventional liposome formation techniques has limited their applications as carriers of nutrecuticals in food industry. The objective of this research is the production of gamma-oryzanol bearing nanoliposome by using modified thermal method. Nanoliposomes were produced by a suitable concentration of lecithin and gamma-oryzanol solution. Size and zetapotential of nanoliposomes was determined using laser light scattering method and Infrared spectroscopy (FTIR) was employed for detection of interaction type between the nanoliposome and gamma-oryzanol. Then, the prepared samples were tested in terms of turbidity, stability, and rheological properties. The FTIR results demonstrate that interactions between lecithin and gama-oryzanol are weak physical type. The results of particle size showed that size distribution (span) were in the range of 90-110 nm and 0.69- 0.90, respectively. The negative zeta potential and loading capacity were reported 20.4 mV and 15.7% (±0.07), respectively. The results indicated that the prepared samples were stable in the 4 ˚C temperature. Increase of lecithin concentration increased turbidity. It was observed that the viscosity not changed by increasing the shear rate (Newtonian behavior), suggesting a nonflocculated system with very small particle size pointing toward the stability of the system.
