Food Chemistry
Masoumeh Heydari Gharehcheshmeh; Akram Arianfar; Elham Mahdian; Sara Naji-Tabasi
Abstract
[1]Introduction: Sesame oil and sweet almond oil are rich in unsaturated fatty acids and antioxidant components, providing nutritional and functional properties including improvement of the gastrointestinal system, decrease in blood cholesterol level, eventually leading to a decrease in the risk of cardiovascular ...
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[1]Introduction: Sesame oil and sweet almond oil are rich in unsaturated fatty acids and antioxidant components, providing nutritional and functional properties including improvement of the gastrointestinal system, decrease in blood cholesterol level, eventually leading to a decrease in the risk of cardiovascular disease. The present study examined the possibility of the production of emulsion based on sesame and sweet almond oils and the effect of preparation on its stability. Material and methods: Sesame oil and sweet almond oil with tween 80 and span 80 as emulsifiers were used in emulsion production. In order to prepare the nanoemulsions, the water and oil phases were prepared separately by the ultrasonic homogenizer. Ultrasonic waves were applied for homogenization and the effect of Ultrasonic time (5, and 10 min), oil content (2, and 4%), and emulsifier concentration (0.25, 0.5%) on particle size, particle distribution index (PDI), turbidity loss rate, emulsion stability and zeta potential of nanoemulsions were studied. Results and discussion: Ultrasonic time had a reverse effect on particle size, particle distribution index (PDI) and turbidity loss rate and a direct effect on emulsion stability. The particle size and turbidity loss rate of prepared emulsions had a direct relation with oil concentration and a negative effect on emulsion stability. Emulsifier concentration had a positive effect on emulsion stability, a negative effect on emulsion stability, and had no significant effect on turbidity loss rate. According to the results of the effect of type and concentration of oil on particle size distribution, turbidity reduction rate and stability of nanoemulsions in all cases, samples containing sesame oil with a concentration of 2% compared to sweet almond oil, had better results, the presence of this oil led to the formation of nanoemulsions with smaller particles and greater stability. The produced nanoemulsions had a particle size between 200-320 nm, a stability of 91-98/7% and a turbidity reduction rate of 0.0010-0.0027. Also, the highest stability and zeta potential were reported 98.7 % and -33mV respectively, which belonged to sample k4. Therefore, this sample was selected as the optimal sample.The results showed that the particle size, mean particle diameter, particle dispersion and turbidity reduction rate showed a significant difference between the samples, so that the lowest and highest were related to K4 sample (2% sesame oil, homogenization time 10 minutes and Emulsifier concentration ratio 0.5%) and sample B5 (almond oil 4%, homogenization time 5 minutes and emulsifier concentration ratio 0.5%) (p <0.05). The results also showed that the highest level of stability and zeta potential was related to K4 sample. Thus, the best nanoemulsion, K4 sample was introduced
Food Chemistry
Roxana Alizadeh Firozeh; Mahta Mirzaei; Vajiheh Fadaei Noghani
Abstract
Introduction: Bioactive peptides are protein fragments with 2 to 20 amino acids that have different biological properties depending on the type of amino acids and peptide sequences, including antioxidant, antihypertensive, and antidiabetic. These peptides are inactive in their parent protein sequences ...
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Introduction: Bioactive peptides are protein fragments with 2 to 20 amino acids that have different biological properties depending on the type of amino acids and peptide sequences, including antioxidant, antihypertensive, and antidiabetic. These peptides are inactive in their parent protein sequences but are released during fermentation, enzymatic hydrolysis, or food processing, and exhibit a positive effect on body function and health being. Lentil protein hydrolysate containing antioxidant peptides can be considered as an ingredient of functional foods. One major challenge in using protein hydrolysate in the formulation of functional foods is their stability against the various processes applied to food such as heat and pH treatments. Materials and Methods: In this study, Lentil protein (Lens esculinaris) was hydrolyzed by Alcalase enzyme under controlled conditions (enzyme/substrate ratio of 90 Anson unit (AU)/ kg protein, 55°C, one hour). The intensity of enzymatic hydrolysis was monitored by the OPA method and antioxidant activity was evaluated based on DPPH and ABTS radical scavenging activity. The heat stability of lentil protein hydrolysate was evaluated by heating samples at 37, 50, 75 (for 15 -60 min), and 90°C (for 5 minutes). The pH stability was investigated by exposing the sample at a pH of 2, 5, 7, 9, And 11 for 1 hr and then adjusting on 7. OPA method was also used to evaluate the possible effect of pH and heat treatments on the content of free amino groups. Results and Discussion: The results showed that hydrolysis of Lentil protein by Alcalase under controlled conditions produced antioxidant peptides. Heating at 37, 50, and 75°C for 15 minutes reduced the DPPH radical scavenging activity by 1.25, 4.9, and 10.17% and ABTS radical scavenging activity by 3.8, 6.8, and 9%, respectively. The results of the OPA assay also showed a significant (P<0.05) decrease in the number of free amino groups in protein hydrolysate exposed to heat treatment. With increasing the time of treatment up to 60 minutes, the antioxidant activity decreased more significantly (P<0.05), simultaneously with a decrease in the content of free amino acid groups in the protein hydrolysate sample. So that, after heat treatment at 37, 50, and 75 ° C for 60 minutes, the free amino acid groups reached from 33/66 μM leucin /mg protein to 29.51, 27.59, and 25.68 μM leucin /mg protein and the most decrease in antioxidant activity was measured for samples exposed to 75°C for 60 minutes. It caused a 27.2%, and 29.2% reduction in DPPH and ABTS radical scavenging activity, respectively. Also, exposure to heat treatment at 90°C for 5 minutes caused a 15% and 13% decrease in DPPH and ABTS radical scavenging activity. The results obtained from consideration the antioxidant activity of samples exposed to pH treatment (2, 5, 7, 9, and 11 for 1 hour) showed the highest antioxidant activity of peptides at neutral pH and confirmed that acidic and alkaline conditions caused a significant decrease in antioxidant activity (P<0.05). As exposure to pHs 2 and 11 for one hour led to respectively 16.3 and a 29.2% decrease in DPPH radical scavenging activity and 16 and 18.2% decrease in ABTS radical scavenging activity. The results of the OPA assay also confirmed the role of acidic and basic pH on less exposure of free amino acid groups in protein structure.The results showed the potential of using Alcalase enzyme to hydrolyze Lentil protein and produce antioxidant peptides and the Lentil protein hydrolysate with antioxidant activity exhibited relative stability toward different heat and pH treatments. It was concluded that peptides retained 88% and 76% of antioxidant activity at maximum heat (90 ° C for 5 minutes) and pH treatment ( pH=11, for 1 hour). According to the results of the OPA assay, the observed decrease in antioxidant activity may be due to the changes that happen in protein and peptide structure when are exposed to heat and pH treatments. Altogether, our results showed that Lentil protein hydrolysate can be considered as a potential food ingredient with stable antioxidant activity.
Fatemeh Saadat; Seyed Hadi Razavi; Houshang Alizadeh
Abstract
Introduction: Oil plants store energy in the form of neutral lipids in the organelles called oil bodies. These organelles save triacylglycerol until seed germination. In recent years, the oil bodies have been considered as an oil/water emulsion in the pharmaceutical, food, and cosmetic industries. These ...
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Introduction: Oil plants store energy in the form of neutral lipids in the organelles called oil bodies. These organelles save triacylglycerol until seed germination. In recent years, the oil bodies have been considered as an oil/water emulsion in the pharmaceutical, food, and cosmetic industries. These organelles are also effective tool for purifying, stabilizing and delivery of biotechnology products. Aqueous extraction processing (AEP) is the most common method for oil body extraction. Despite all advantages compared to organic solvent extraction, the yield of AEP still needs to be optimized. Therefore, this study surveys the efficacy of two solvents, phosphate buffer and distilled water in the oil bodies' extraction from rapeseed. Materials and methods: Brassica napus L. seeds were obtained from seed and plant improvement institute, Iran. To compare the efficacy of solvents, 0.1 M phosphate buffer (pH 7.5) and distilled water were used for extraction. The ground rapeseed was suspended in the buffers in a ratio of 1:10 (w/v) and stirred for 12 hours at room temperature. This step was repeated three times. Then, the extract was centrifuged at 10,000 g for 15 minutes at 4 ° C. The floating layer was carefully removed and dissolved again in the initial solvent and the pH was adjusted to 8.5 to precipitate the deflated proteins. Finally, the cream layer was retrieved using centrifuges and one-tenth of the initial buffer volume was applied to the 9 M urea buffer (pH 7.5) for 10 minutes to separate non-specific proteins from oil bodies. The purified oil-bodies were monitored under light microscopy. Results and discussion: According to the microscopic and macroscopic results, the stability of oil particles and efficiency of extraction would be higher by phosphate buffer due to maintaining a constant alkaline pH during the extraction. Moreover, the presence of different salts in the phosphate buffer increases the purification yield up to twice times as a result of providing osmotic pressure and increasing solubility of membrane proteins. These results emphasize the importance of membrane proteins on the formation and stabilization of oil bodies.
Fatemeh Pourhaji; Farideh Tabatabaei Yazdi; Seyed Ali Mortazavi; Mohebbat Mohebbi; Mostafa Mazaheri Tehrani
Abstract
Introduction: Banana is one of the most consumed fruit in the world and is cultivated almost in all tropical countries. This fruit has a high nutritional value and is a suitable source of energy due to the presence of high amount of starch, sugar, vitamin A and C, potassium, sodium, and magnesium. Banana ...
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Introduction: Banana is one of the most consumed fruit in the world and is cultivated almost in all tropical countries. This fruit has a high nutritional value and is a suitable source of energy due to the presence of high amount of starch, sugar, vitamin A and C, potassium, sodium, and magnesium. Banana is highly vulnerable after harvesting and is subject to the microbial spoilage due to the high moisture content which makes difficult its sales and exports. Therefore, several methods have been used to overcome these problems. Drying and dehydration are methods to extend the shelf life of banana which usually carries out by hot air. This method can prevent some degree of microbial spoilage, but it has some disadvantages such as changing color, taste, flavor and reducing the nutritional value.
Foam-mat drying as a substitute for hot air drying introduces some advantages such as using the microwave energy. In this method, food products are whipped to form stable form and then dehydrated by thermal means. Due to the larger surface area and accelerated moisture transfer from foam, food products can be dried at lower temperature and time by this method of drying. Moreover, the porous structure of dried foam results in a faster rehydration and solubility of dried food samples. Additionally, microwave-assisted drying results in a product with better quality because of faster rate and saving energy.
Materials and methods: The fresh banana was cut into small pieces with a diameter of 1.0 mm after peeling. To prevent the enzymatic browning of samples, blanching was carried out by boiling water (100 °C) for 3 min. After that, the banana cuts were placed in a container containing 10°C water in order to cool. To produce pulps, the homemade Bosch mixer (model w600, CNSM, 30EW, Slovenia) at a speed of 1500 rpm and 1.0 min was used. Then, the pulps were mixed with skim milk at different concentrations (3-6 % w/w) and homogenized by ultra-turrax (IKA® Labortechnik) at 10000 rpm for 5.0 min. Moreover; the prepared xanthan gum was added to the mixture at concentrations of 0.15 and 0.25%. Xanthan gum was prepared by adding 1.0 g gum into 100 mL water and mixing by magnet stirrer. Afterwards, the gum solution was kept overnight at 4 °C for complete hydration. Finally, the sample transferred into the foam-maker device which was connected to a nitrogen gas tank with different flow rate (0.2-2 L min-1). The speed and time were adjusted to 16000 rpm and 5.0 min, respectively. After the producing of banana milk foam and selecting optimum sample based on the lowest density and the highest stability, the drying kinetic of this sample was studied. Then the banana milk foam was dried using microwave (360, 660 and 900 V) in a glass plate with diameter of 3.0 and 5.0 mm. Foam density and stability were determined by the methods of Xian-Zheetal (2010), Stauffer (1999) and Bag et al. (2010). The color of samples was studied by hunterlab. Moisture content also was measured based on the AACC standard method (AACC, 2000). Glass transition temperature also was determined by differential scanning calorimetry (DSC, model OIT-500 Sanaf Electronics Co, Iran).
Results and Discussion: In the present study, foam-mat method and microwave drying were used to reduce the drying damages. Nitrogen gas and xanthan gum also were used respectively to control foam generation and improve the stability of foams. Optimization of the banana milk production was carried out using response surface methodology based on three variables including the rate of nitrogen gas (0.2-2 L min-1), concentration of xanthan gum (0.15-0.25 %) and milk to banana ratio (1:6 and 1:3). Optimization was done based on the highest stability and lowest foam density. The optimum condition was proposed as the nitrogen gas rate of 0.2 L min-1, xanthan gum of 0.22 % and 3% banana which showed the density of 0.39 and the highest stability (0 mL after 1.0 h). After that, the optimum sample was dried by microwave. The effects of three levels of microwave voltage (360, 660 and 900 V) and two diameters (3 and 5 mm) were evaluated for drying of optimum sample. The results showed that the sample dried with diameter of 3 mm and voltage of 900 V had the highest L*, highest glass transition temperature and the lowest moisture content.
Hassan Mirhojati; Parvin Sharayei; Reihaneh Ahmadzadeh Ghavidel
Abstract
The acidified ethanol extracts of dried barberry which have a relatively high anthocyanin content (376.28± 1.45 mg c3g/Kg dmp) were freeze dried using maltodextrin (MDX), polyvinyl-pyrrolidone (PVP) and mixture of MDX and calcium alginate (MDX-CaAlg) as a carrier and coating agents. The qualitative ...
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The acidified ethanol extracts of dried barberry which have a relatively high anthocyanin content (376.28± 1.45 mg c3g/Kg dmp) were freeze dried using maltodextrin (MDX), polyvinyl-pyrrolidone (PVP) and mixture of MDX and calcium alginate (MDX-CaAlg) as a carrier and coating agents. The qualitative attributes of the powders were characterized by their productively encapsulation efficiency, moisture content, bulk density, colour values (L*, a*, b*, C and H° ), particle size, total phenolic compounds (TPC), free radical scavenging activity of DPPH (RSA), ferric reducing-antioxidant power (FRAP) and minimized 50% of radical- scavenging activity (IC50). Scanning electron microscope was used for monitoring the structures of the powders. To determine the stability and half- life period of microencapsulated pigments, samples were stored under different storage temperatures (4◦C and 25◦C) at relative humidity 75%. Results showed that the encapsulated powder containing PVP 8% as wall material represented the best powder quality (p
Afsaneh Sadeghi; Ahmad Ghazanfari; Hassan Hashemipoor Rafsenjani; Hamidreza Akhavan
Abstract
Introduction: Moringa is a tree that grows in hot and humid regions and produces oil seeds that contain about 33% edible oil. The tree is native to the south-west regions of Asia and it is cultivated in Hormozgan and in Sistan and Bluchestan provinces of Iran. The oil extracted from these seeds is edible ...
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Introduction: Moringa is a tree that grows in hot and humid regions and produces oil seeds that contain about 33% edible oil. The tree is native to the south-west regions of Asia and it is cultivated in Hormozgan and in Sistan and Bluchestan provinces of Iran. The oil extracted from these seeds is edible and has some various industrial applications. The extracted oil usually contains considerable amount of dissolved impurities which must be removed prior to industrial usages. Major part of impurities is removed by settling or filtering process. The fine impurities are removed through a degumming process using water, acids or enzymes. The degumming process affects the physco-chemical characteristics of the oil. In this research, various physco-chemical and heating properties of Moringa oil was measured and the stability of the oil under elevated temperatures were investigated
Material and methods: The Moringa seeds were collected from the wild trees that grow in Hormazgan province. The seeds were manually cleaned and ground to mean diameter of less than 1 mm and then were placed in an oven at 65°C for 24 h to reduce their moisture. Samples of 50 g ground seeds were placed insoxhelt and n-hexane was used as the solvent. The oil extraction experiments were conducted at 60°C for 7 h retention time. The raw obtained oil was divided into two parts and one part was degummed. The degumming of the oil was performed by adding distilled water to it and raising the temperature to 80°C. Then, phosphoric acid was added to the mixture and stirred for 20 min at the same temperature and the mixture was centrifuged and the oil was separated from water and wax. Some characteristics of the raw and the degummed oils including: fatty acids, ion value, peroxide value, chemical, color, saponification value, ignition and clouding points, density and viscosity were measured and compared. The stabilities of the viscosity of the two oils were investigated under different temperatures ranging from 3 to 120°C. The oxidative stability of oils was determined against temperature, light and air exposure. In these experiments temperature ranged from 20 to 120°C, light and air exposure time were 10 days, each. High temperature stability of the oils was also verified using a Rancimat instrument.
Results and discussion: The results of fatty acids analysis indicated that the Moringa oil is generally unsaturated oil containing a total of 76% pulmonic and oleic acids. The major saturated oil content of Moringa oil was plasmatic acids which accounted for 14.3% of the total fatty acids. High amount of unsaturated acids indicates that this oil is good for cooking purposes. The degumming process caused a significant decrease in peroxide value, saponification number and total fatty acids but the viscosity and the pH of the oil increased which all indicates that the degummed oil should be more stable than the raw oil. All heating properties of the degummed oil such as melting, combustion, pour, and cloudy points of the degummed oil increased which indicates that the degummed oil is more suitable for heating foods. In investigating the stability of the oil, the viscosity of the Moringa oil was decreased as the temperature of the oil was increased however, the viscosity increased with the holding time. The increase of the viscosity was more significant at higher temperatures due to the oxidation and degradation of the oil. Generally, increase in the viscosity of the degummed oil occurred at with lower rates. The peroxide value of the raw and the degummed oil was increased as the temperature of them was increased. The increase had higher rates when temperature of the oil exceeded 60C. The peroxide value was also increased with the holding time. The change was not significant for the first four days but it rapidly increased after that. The peroxide value of the oil that kept away from the sunlight remained unchanged for the 10 days test period. The value of peroxide was also affected by aerating the oil. Degradation was initiated immediately as aeration was started but a steep increase was noticed after the second day. The highest peak was reached on the sixth days and after that the oil was completely degraded. A Racncimat test on the raw and degummed oil indicated that with increase in the oil temperature the stability of the oil decreased and when temperature was at 110°C the stability of the raw and the degummed oils were 19 and 31 hours. In general, all the tests indicted that the degummed Moringa oil had higher stability than the raw oil.
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
Samira Tizchang; Mahood Sowti Khiabani; Reza Rezaeemokaram
Abstract
Nisin has numerous applications as a natural preservative in foods, including dairy product, canned food, processed cheese and milk. Several studies demonstrated that proteolytic degradation and the interaction of nisin with food components might result in decreased its antimicrobial activity. Encapsulation ...
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Nisin has numerous applications as a natural preservative in foods, including dairy product, canned food, processed cheese and milk. Several studies demonstrated that proteolytic degradation and the interaction of nisin with food components might result in decreased its antimicrobial activity. Encapsulation of antimicrobial peptides into nanoliposomes may offer a potential alternative to protect antimicrobials, enhancing their efficacy and stability for food applications. In first stage of this research, Response Surface methodology was used for optimization of nanoliposomes produced by heating method. A central composite design (CCD) consisting of 18 experimental run with three independent variables: phospholipid concentration (2-30 mM), stirring speed (500-1360 rpm) and processing time (30-90 min) were used and their effects on size of nanliposome were evaluated.In the next stages, stability of nanoliposomes was investigated during 2 month. The optimum operating conditions obtained from the quadratic form of RSM model for particle size were phospholipids 30 (mM), stirring speed 930 (rpm) and process time 90 (min). The results of stability indicated that samples in the range of 400 to 500 nm were stable up to 2 month (P > 0/05) but samples larger than 500 nm were unstable during 2 month but stable up to 1 month(P> 0/05).
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.
Mohsen Esmaiili; Ali Hassanzadeh
Abstract
The sorption isotherm and state diagram of sundried, golden and sultana raisins were constructed for investigation and comparison of the product stability. The isotherms were measured at 15, 25 and 35 °C using an isopiestic method and the data were modeled with GAB model. Glass transition temperatures ...
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The sorption isotherm and state diagram of sundried, golden and sultana raisins were constructed for investigation and comparison of the product stability. The isotherms were measured at 15, 25 and 35 °C using an isopiestic method and the data were modeled with GAB model. Glass transition temperatures of the products were measured by differential scanning calorimetery (DSC) and fitted to Gordon Taylor model. Moisture sorption results indicated that the amount of moisture adsorption and the GAB monolayer moisture contents were the highest in sultana and the lowest in sundried raisins, at all of investigated temperature levels. Critical water activity (CWA) and critical water content (CWC) were estimated from the state diagram and the relationship between water activity, the glass transition and the equilibrium moisture content. According to the state diagram specification, CWC (dry basis) and CWA of raisins were estimated lower than 0.03 and 0.05, respectively.
