جستجوی مقالات مرتبط با کلیدواژه « essential oils » در نشریات گروه « صنایع غذایی »

Recently, the use of new packaging materials and natural additives for improving the durability and preservation of foods has been increasingly considered. Edible coatings containing plant extracts lead to increase the shelf life of food, do not cause environmental contamination, and do not endanger the health of the consumer. Fish is a food rich in amino acids, vitamins and minerals, and polyunsaturated fatty acids, especially omega-3, which has made it more and more popular in the human diet. However, the presence of a significant amount of polyunsaturated fatty acids as well as easily digestible proteins has turned fish into a highly perishable commodity. Fresh seafood spoils rapidly due to the enzymatic and bacterial activities that occur after death, as well as the spoilage caused by the oxidation of polyunsaturated fatty acids and the high concentration of hematin compounds and metal ions of fish muscle, such as iron, and their pH which is close to neutral. Therefore, the use of natural coatings that can increase the shelf life of food and attract the consumers should be given more attention. Iran is the largest fishery producer in the region, thus, providing new methods to increase the shelf life of these products until the time of consumption can guarantee the safety and be effective in the economic prosperity of this industry. Therefore, the present study was designed to investigate the effect of chitosan coating along with the volatile oil of ginger plant on the shelf life of salmon fillets stored in refrigerator to reduce microbial growth, reduce chemical reactions, and increase the storage life of salmon fillets in refrigerator.

Rainbow trout fish with an approximate weight of 600 grams were purchased from the market. Fish were washed with sterile distilled water, and cut into 60-gram pieces after separating the head and tail and eviscerating. The prepated fish were randomly divided into 4 groups. The control group was without any treatment but the treatment groups were immersed in chitosan containing different concentrations of Ginger essential oils. All the samples were kept in zipped bags at refrigerator (4°C) for 15 days. Microbial tests (Mesophilic, Psychrophilic, Coliform, and Lactic acid bacteria count), chemical tests (pH, TVN, TBARS), and sensory tests (color, smell, taste, texture, and overall acceptance) were performed on days 1, 4, 7, 12 and 15. The data obtained from the microbial and chemical tests were analyzed by one-way analysis of variance and the data obtained from the sensory tests were analyzed by the Kruskal-Wallis test in Sigma Stat 4 statistical software, considering P<0.05.

 The results of bacterial tests showed that chitosan coating with ginger essential oil had a significant effect on reducing the growth of mesophilic, coliform, lactic acid bacteria and psychrophilic bacteria compared to the control and chitosangroups during 15 days of storage in the refrigerator (P<0.05). During the storage period, chitosan-treated groups containing 1.5% and 0.75% of ginger volatile oil had the best microbial quality in terms of mesophilic bacteria, Psychrophilic bacteria, lactic acid- bacteria, and coliforms. Also, in samples immersed in chitosan coating with ginger essential oil, the pH, TVN and TBARS values at the end of the storage period were significantly lower than the control and chitosan group (P<0.05). The results showed that pH, TVN, and TBARS did not exceed the defined standard for fish meat at the end of the storage period in the groups treated with ginger volatile oil. Sensory characteristicsindicated that the groups treated with chitosan coating containing ginger essential oils showed better sensory characteristics in terms of color, taste, smell, texture, and overall acceptance than the control and chitosan groups during the storage period (P<0.05).

Based on the results of the present study using the chitosan coating combined with ginger volatile oils has antimicrobial and antioxidant properties, which can reduce the oxidation of fats and microbial loads, while maintaining the organoleptic quality and increasing the shelf life of fish meat at refrigerator temperature. In comparison between treated groups, the use of chitosan along with 0.75% volatile oil of ginger is recommended, because by using a smaller amount of volatile oil, the microbial, chemical, and organoleptic properties can be kept at the standard level until the 15th day.

Cucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. Therefore, pretreatments are crucial for prolonging its shelf life. Chitosan is a cationic polysaccharide and can interact electrostatically with anionic, partially demethylated pectin. Besides, chitosan has inhibitory effects on fungal rot and prevents weight loss in fruits. Pectin can form excellent films. Because of increasing demand to reduce synthetic chemicals as antimicrobial agents, substances derived from plants, such as essential oils, can play a significant role in the future.  Several essential oils and essential oil components have shown antimicrobial activity against spoilage and pathogenic microorganisms during fruit and vegetable storage. Essential oils of thyme and cinnamon contained phenolic groups have been found to be most consistently effective against microorganisms, however, essential oils are volatile and irritant. Therefore, forming an inclusion complex using b-cyclodextrin can improve solubility, control volatile, and induce off-flavors and unpleasant odor of the essential oils. The objectives of this study were to develop the microencapsulated thymol (thyme) and trans-cinnamaldehyde (cinnamon) essential oils to produce antimicrobial agents and subsequently evaluate the effectiveness of edible coating made of chitosan and pectin containing microencapsulated trans-cinnamaldehyde or thymol essential oils to improve qualitative and quantitative characteristics and shelf life of cucumber.

The inclusion complexes of trans-cinnamaldehyde and thymol in beta-cyclodextrin (CD) were prepared separately by freeze-drying. Each essential oil was dispersed in 1000 ml of beta-cyclodextrin aqueous solution (16 mmol/L, 18.15 g) in molecular ratio 1:1 (2.4 gr thymol, 2.11 gr trans-cinnamaldehyde) and mixed in a laboratory stirrer for 24 hour at room temperature , then frozen (-70 ºc) and freeze-dried (<20Pa, 48 h). Lyophilized samples were stored inside a freezer (-20 ºc) until further use. Cucumbers cv. Nagene with uniform size, appearance, ripeness and without mechanical damage or fungal contamination were selected. Then They were then sanitized by immersion in chlorine solution (150 mg/kg) for 1 min and air dried. Edible coatings were prepared as three immersion solutions of chitosan, pectin, and calcium chloride (CaCl2). The fruits were coated with pectin (1%) and chitosan (0-0.5%-1%) containing beta-cyclodextrin microencapsulated trans-Cinnamaldehyde or thymol each (0-0.25%-0.5%). After coating by chitosan, the fruits were immersed in 1% Calcium chloride solution to induce crosslinking reaction. After dipping step, fruits dried for 8 minutes at room temperature to remove the excess solution attached to the surface .Uncoated fruits served as control. Then fruits were preserved in cold storage (temperature: 10ºc; relative humidity: 90-95%) for 15 days. chemical (total soluble solids, titratable acidity) and physical (total color difference, Hardness, and weight loss) Characterization of fruits were measured immediately after harvest and after 5, 10 and15 days. Microbial tests (total count, mold, and yeast) were done at the end of preservation time. Analytical data were subjected to analysis of variance and factorial adopted completely randomized design and a Duncan comparison test was used. 

The results showed that weight loss, total soluble solids, and the total color difference increased and hardness and titratable acidity decreased gradually in all samples during cold storage (<0.05). Chitosan and essential oils slowed down this rising or decreasing trends. Interactive effects of chitosan, essential oil type, essential oil concentration, and storage time had positive effects on these quality attributes. The fruits coated with the highest concentration of chitosan (1%) and thymol (0.5%) essential oils showed the least weight loss, loss of hardness, and color change throughout 15 days of storage. Besides thymol in comparison with trans-Cinnamaldehyde was more efficient to prevent yeasts and molds on the surface of cucumber. By increasing chitosan and essential oil amounts, the ability of inhibiting microbial growth by coating is enhanced. 

The results of chemical, physical and microbial tests, showed that multi-layer coating solution containing chitosan 1% with thymol 0.5% was effective in extending the shelf life of cucumber. The combined usage of microencapsulated thymol essential oil and chitosan-based coating on cucumber could be considered a healthy and effective treatment that reduces microbial spoilage and preserves quality and color characteristics in cucumber and represents an innovative method for commercial application. Therefore, this coating can be used as an alternative to chemical fungicides to prevent fungal rot of cucumber and other fruits, however, it is suggested that more studies should be done in this field.

In the first step of this study, Anethum graveolens and Nasturtium officinale essential oils prepared with Clevenger apparatus and then, essential oils ingredients evaluated by GC-Mass. Minimum Inhibitory (MIC) and Minimum Bactericidal Concentration (MBC) and antioxidant activity of essential oils were evaluated at concentrations of 350, 400, 500, 600 and 650 mg/L during 60 days. Then, encapsulated essential oils of A. graveolens and N. officinale in the mentioned concentrations by maltodextrin and coacervation methods to evaluate morphology and particle size distribution. Finally, to achieve the optimal concentration of essential oils in order to further preserve the probiotic population of Bifidobacterium lactis, the viability of this bacterium in doogh was evaluated for 21 days. In the second step of the study, the effect of adding essential oils on optimal concentration to the product investigated according to dry matter content, pH, acidity, serum separation rate, rheology and sensory evaluation. The results showed the essential oils have high terpene and phenolic content, which caused proper antioxidant and antimicrobial activity. The viscosity, consistency and acidity of the final product increased on the other hand, pH and serum separation rate decreased significantly. Considering the results of sensory evaluation and lack of any negative effects at optilam concentrations of 400 mg/L and 500 mg/L for A. graveolens and N. officinale essential oils, respectively, the possibility of its industrial application can be examined.

In recent years, the use of natural antimicrobial compounds in food has attracted the attention of consumers and researchers, the two main reasons for this is the excessive and incorrect use of antibiotics due to the selective pressure it exerts on microorganisms It creates resistance to antibiotics, thus increasing a group of microorganisms, including pathogens in food, which are not only resistant to antibiotics but also resistant to food processing and storage methods. Increasing public awareness of the potential negative effects of artificial preservatives on human health versus natural additives has led many researchers to focus more on the use of natural preservatives in food. Many compounds obtained from natural sources have antimicrobial properties and can be used to maintain food safety. Today, the use of food preservatives has become a necessity that plays an important role in the storage and transportation of food. The goals of adding preservatives to foods are to preserve the appearance of the food, to help preserve the organoleptic properties, and to increase the shelf life of the food. In this review article, we will examine the antimicrobial activity of some natural compounds obtained from different sources and their mechanism of action.

The drying process plays an important role in the treatment of medicinal plants, in order to maintain the quantity and quality of the essential oil extracted from the plant. Because Medicinal herbs containing essential oils If they are not dried immediately or their essence is not extracted, they will lose their active ingredients and volatile compounds.The aim of this study is design a hybrid dryer to drying medicinal plants and comparison their results with traditional drying methods (sun and shade).The effects of different drying methods (hybrid dryer, oven and shade drying) on the essential oil content and chemical composition of thyme were studied. The essential oils from each organ type were extracted by hydrodistillation and the chemical components were analyzed by GC/MS systems. Mathematical modeling results showed that the Midilli model can fit the drying curves with high accuracy. The highest essential oils yield of 2.4 % (v/w) was obtained by a hybrid dryer. Results indicated that hybrid dryer could keep the 24 Kinds of volatile compounds of Thymus while these values were 10 and 6 for oven and shadow methods, respectively. The main components of the essential oils in different drying methods were including alpha and beta pinene, caryophyllene, caryophyllene oxide, carotol, thymol, thymol methyl ether, terpinene-4-ol, gama-terpinene, p-cymene.In general, hybrid drying method is recommended as the best method for post-harvest thyme processing.

The encapsulation of essential oils in nanoliposomes is an effective method for protecting them from light, oxygen and chemical degradation. In this study, nanoliposomes containing kakuti essential oil were prepared from different concentrations of lecithin-cholesterol (60:0, 50:10, 40:20 and 30:30 mg) by thin-layer hydration-sonication method. The GC-Mass spectroscopy method was used to study essential oil composition and the results showed that Pulegone (49.05%) was the main component of essential oil. Particle size, poly dispersity index (PdI), zeta potential, and the encapsulation efficiency were evaluated to determine the physical properties. Antibacterial activity of nanoliposomes against E. coli O157H:7 were investigated using a disk diffusion agar method, the minimum inhibitory concentration (MIC) and minimum bactricidal concentration (MBC). The size of particles and PdI were in the range of 88.60-121.97 nm and 0.114-0.169, respectively. The results showed that using the highest concentration of cholesterol for preparing of nanoliposomes containing essential oil increased the size and PdI, but reduced the encapsulation efficiency. Cholesterol concentration did not have a significant effect on zeta potential, and only the sample containing 30 mg of cholesterol had a higher zeta potential. MIC and MBC of cholesterol-free nanoliposomes containing essential oils were 14 and 14 μg/ml and for the control sample (free essential oil) were 15 and 30 μg/ml, respectively. The antimicrobial activity of nanoliposomes decreased with increasing cholesterol levels in the samples. The results of this study showed that nanoliposomes could be a suitable carrier for kakuti essential oil to control the growth of E. coli.

The complex composition of the essential oils and the variety of chemical structures of their constituents are responsible of a wide range of biological activities many of which are of increasing interest in the field of foodstuff preservation (Romanazzi et al. 2012). Regarding that higher amount of EOs are required for food preservation, their application can negatively influence taste or odor. To avoid this unwanted side effect, several EOs can be combined. On the other hand the synergistic possible effect produced by the combination of plant essential oils was referred as an efficient strategy to combat microbial development(Wagner. 2011). The main purpose of this study was to evaluate the antifugal synergistic effect of combination of some essential oils including thyme, cinnamon, rosemary and marjoram aginst apple rot fungi during posthrvest storage. In this experiment, chemical composition of the essential oils was analyzed by gas chromatography. For evaluation of antifungal activity based on MIC, against Alternaria alternanta, Penicillium expansum and Botrytis cinerea, an agar dilution method was used. EOs interactions were assessed using a checkerboard microdilution method. The evaluated concentrations were in the range of 5 dilutions below the MIC to twice the MIC. For the double combinations, a two-dimensional checkerboard with twofold dilutions of each EOs was used (six double combinations). The maximum antifungal activity was demonstrated by thyme oil which showed MIC values 1250 μg/mL for A. alternanta and P.expansum and 625 μg/mL for B. cinerea .Cinnamon oil with MIC values1250 μg/mL against A. alternanta and B. cinerea and 2500 μg/mL against P.expansum displayed more inhibitory effects than rosemary and marjoram essential oils. In antifungal synergy testing, some double combinations (thyme/rosemary, thyme/cinnamon and cinnamon/marjoram) were found to be synergistic (FICi≤0. 5). The in vivo assay also demonstrated considerable inhibitory effects of EO combination treatments. Results from artificial wounding of trated apple indicated that double combination of thyme/cinnamon (156, 312 μg/mL) has more inhibitory effect than single EO treatments. Although the major components of thyme and cinnamon (especially thymol, carvacrol and cinnamaldehyde) are very important for their antifungal activity, other less-active compounds in rosemary and marjoram (such as α–Pinene, 1.8-cineole, Terpinene-4-ol and γ-Terpinene) play a significant role, as they can strengthen the effects of major components, though synergistic effects have also been observed

Due to the side effects of chemical preservatives and the increasing consumer's demand for herbal and natural compounds, the use of essential oils as a food preservative have been widely studied. The aim of the present study was to investigate the chemical compound of Ziziphora cliniopodiodes and Thymus daenensis essential oils and their antibacterial properties against some food borne pathogenic bacteria. The eessential oils were analysed by gas chromatography/mass spectrometry (GC/MS) .A microdilution method in 96-well plate was used to evaluate the minimum inhibitory concentration (MIC) of essential oils. According to the results of MIC, the evaluation of minimum bactericidal concentration (MBC) of essential oils were determined. All experiments were done triplicate and average of data were determines as results of MBC and MIC. Statistical analysis conducted by SPSS software edition 22. Among the detected compounds, Ziziphora clinipodiodes essential oils by gas chromatography coupled with mass spectrometry (GC/MS), Thymole (34.25percent) Pulegoneand (14.41percent), Carvacrol (10.91percent) and in Thymus daenesis, Carvacrol (37.20percent) and octadecenuec acid methyl ester (21.67percent) were dedicated the highest values. The results of this research revealed that minimum inhibitory concentratin of ziziphora clinipodiodes essential oils and Thymus daenesis were 0.61-1.25 and 0.31-1.25 mg/ml, respectively. Generally, antibacterial effect of ziziphora clinipodiodes were greater than Thymus daenesis. In addition, sensitivity of gram positive bacteria in both essential oils were evaluated higher than gram negative bacteria.

Recently by no incident there is a great concern in people to consume herbal antibiotics rather than using chemical ones due to bacterial resistances witnessed in chemical treatments. In this research the antibacterial activity of aqueous and ethanol extracts of black zira cell suspension culture in comparison with seed extracts and essential oils were investigated against Staphylococus aurous, Escherichia coli and Bacillus subtilis using disk diffusion and digging hole methods. The bacterial concentration was at 106 and 107 CFU/mL. Positive and negative controls were antibiotics (Gentamicin [10 μg/disk], Tetracycline [30 μg/disk]) and solvents (5% DMSO and 80% Ethanol) respectively. Inhibitory effects were studied by measuring the growth inhibiting circle diameter. The Results showed that the range of Minimum Inhibitory Concentration (MIC) were 3.12-6.25, 12.5-50 and 25-50 mg/ml, for the essential oil, the cell extract and the seed extract respectively. According to the results a promising antibacterial activities were revealed from all black zira samples against tested bacteria with the maximum activity to the S. aurous. In contrast to E. coli, the effect of extracts on S. aurous and B. subtilis was dependent to the bacteria concentration. Overall antibacterial effects of cell extracts against tested bacteria were lesser than essential oils (100%) and higher than seed extracts and different dilution of essential oils, therefore it seems cell suspension culture of black zira is a suitable method to produce antibacterial compounds.

In this study the antimicrobial effects of essential oils from dill and coriander seeds onstaphylococcus aureus, Escherichia coli O157:H7 and salmonella typhimuruim were investigated and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each essential oil were determinate. For this purpose 5 concentration of each essential oils (125, 250, 500, 1000, 2000 and 4000 ppm) were chosen. For microbial count, Broth Dilution Test with Mueller Hinton Agar and Broth were used. Results showed that Staphylococcus aureus had more susceptibility and Salmonella typhimuruim was the resistant one. Our results also showed that essential oil from coriander seed had more antimicrobial effect on the gram-negative bacteria. The essential oil from coriander seed had MIC and MBC equal to 1000ppm and the essential oil from dill seed had MIC equal to 500ppm and MBC equal to 1000 ppm against Staphylococcus aureus.