Showing 18 results for Preservation
Volume 4, Issue 3 (9-2018)
Abstract
Aims: Transportation of clinical samples and long-term recoverability of fungal strains are critical to epidemiological studies. In addition, the study of fungi often requires the use of living pure cultures. The aim of this study was to evaluate the methods used to preserve culture collections of dermatophytes, consisted of storage in sterile distilled water, cryopreservation with glycerol, preserving in tryptic soy broth (TSB), and freezing mycobiotic agar.
Materials and Methods: in this experimental study, ninety-two dermatophyte isolates belonged to 10 species were tested. The freezing protocol was done in 4 forms of sterile distilled water, cryopreservation with glycerol, freezing mycobiotic agar, and preserving in TSB. The viability of the dermatophytes species was assessed after 3 years at morphological (macro and microscopic features), physiological (Using Dermatophyte Test Medium; DTM, urease test media, and the hair perforation test), and genetic levels by restriction fragment length polymorphism (RFLP).
Findings: The survival rate was 84 out of 92 water stored fungal strains (91.3%) and 81 out of 92 mycobiotic agar stored strains (88.0%) and 75 out of 92 glycerol 40% stored strains (81.5%) and 43 out of 92 TSB stored fungal strains (46.7%). Overall, more than 88% of the strains survived in the distilled water storage and freezing mycobiotic agar, methods, while storage in TSB had the least success in the maintenance of dermatophytes.
Conclusion: The procedure to preserve cultures in sterile distilled water is reliable, simple, and inexpensive.
Volume 5, Issue 18 (10-2008)
Abstract
The aim of this study was to demonstrate the inhibitory capacity of two strains of gram positive bacilli, isolated from intestinal content of Persian sturgeon, against Listeria monocytogenes growth. Two strains Lactobacillus casei AP 8 and Lactobacillus plantarum A P 12 , were screened for their antilisterial activity against. L. monocytogenes, using a disk diffusion agar test. However, L. casei AP 8 always had the highest inhibitory effect. The spoiling potential and antilisterial capacity of bacterial strains was tested in sterile cold smoked roach (CSR) blocks inoculated with 104 CFU g− 1 of lactic bacteria and 102 CFU g-1 of Listeria monocytogenes and then stored for 10 days at 4 °C followed by 30 days at 20 °C. L. casei AP8 grew a little faster L. plantarum A P 12 and none of them showed any adverse effect on quality of the product ( i.e. no total volatile basic nitrogen (TVBN) production and no acidification. Lactobacillus casei AP8 was the most efficient strain, maintaining the level of L. monocytogenes at <50 CFU/ g during 40 dayss of storage at 4 and 20°C. In conclusion, biopreservation of cold smoked roach using bacterial cultures such as L. casei AP8 is a promising way to inhibit the growth of pathogenic bacteria such as L. monocytogenes with low effect on the product quality.
Volume 8, Issue 34 (12-2011)
Abstract
The aim of this study was to develop a biopreservation strategy for cold-smoked Caspian roach by the use of Lactobacillus casei previously selected for their capability to inhibit the growth of Listeria monocytogenes in this product. An application on commercial smoked Caspian roach was tested by spraying L. casei (104 CFU g-1) on slices smoked Caspian roach. Microbial and chemical characteristics were each ten days compared to a control during forty days of storage. No significant differences were showed in microbiological and chemical characteristics of inoculated slices with L. casei. The strain L. casei inoculated in SCR in a biopreservation goal exhibits some interesting properties: it is able to grow at high level without giving major quality changes in the product. In conclusion, biopreservation of SCR using lactic acid bacteria such as L. casei is a promising way to inhibit the growth of pathogenic bacteria such as L. monocytogenes with low effect on the quality of the product.
Rouhollah Ahangar, , , , ,
Volume 9, Issue 4 (11-2020)
Abstract
The aim of this study was to investigate the effect of chitosan as a natural preservative. Farmed fish were washed and filleted. In this study, 3 types of chitosan were investigated: acid-soluble chitosan, water-soluble chitosan and oligosaccharide chitosan. The fillets were immersed in the above solutions for 30 seconds, and then removed, and after 2 minutes, the immersion was repeated. Control samples were uncovered. The fillets were then placed at room temperature (20 °C) for 2 hours to form a coating on the fillets. 192 pieces of 100 g fish fillets were divided into 4 treatments and each treatment was divided into 4 times: treatment one as a control (without preservative), the second treatment containing 1% acid-soluble chitosan, the third treatment containing 1% water-soluble chitosan and the fourth treatment containing 1% Chitosan oligosaccharides. All samples were stored in refrigerator at 4±1 °C and their chemical parameters (Peroxide, pH, Thiobarbituric acid, Total Volatile Nitrogen) were measured on (0, 4, 8 and 12) days. All the indices of treatments had increasing trend over time. Only in the pH index of 1% acid-soluble chitosan had an irregular trend. 1% acid-soluble chitosan had the most positive effect in all treatments. Due to increase in chemical indices in all treatments, the addition different of chitosans to fish fillets could prevent or reduce them.
Volume 10, Issue 38 (1-2013)
Abstract
Active packaging is one of the innovative food packaging concepts which has been introduced to market as a reply to continuous changes in consumers demands. Active packaging modifies the packaging atmosphere condition in such a desirable way that results in shelf-life increase. In contrast to the traditional concept that packaging should preserve the quality of the product with minimal product/packaging interaction, new developments achieved in the last decades considers the benefits of interactions between package and product. Active modified packaging has been used for food preservation over the last twenty five years specially in Japan and USA. The application of different kinds of this package is developing continuously. Active packaging includes additives that can maintain the freshness of the product and have different potentialities .Active agents are in contact with food stuffs directly or indirectly and can be in the forms of oxygen and carbon dioxide scavengers, moisture and ethylene removers or emit ethanol and flavors. Those with the ability to change physical properties like self-heating or cooling are also considered an active package. Active packages have been used for a variety of food stuffs such as cakes, pizzas, fresh dough, cheese, meats and its products, fruits, breads etc.
Volume 12, Issue 2 (4-2010)
Abstract
Iran is one of the main date (Phoenix dactylifera) producing countries in the world. however, little information is available on the pollen viability and favorable storage conditions of Iranian male date cultivars. This study was conducted to estimate the best in vitro pollen germination of three male date palm cultivars, `Ghanami’, `Samsmavi’ and `Gheibani’ using various doses of boric acid (0, 50, 100 and 200 mg L-1), calcium nitrate (0, 200 and 300 mg L-1) and sucrose (15% and 25% (w/v)) in a Modified Brebaker and Kwack (MBK) medium. The results showed that the best germination was achieved with 50 mg L-1 boric acid, 200 mg L-1 calcium nitrate and 15% (w/v) sucrose. Once the optimal in vitro germination medium had been established, pollen viability (% germination) of these three cultivars stored for up to 200 days at room temperature (dark and light), in a refrigerator (4˚C), freezer (-20˚C) and in liquid nitrogen (-196˚C) was compared. For all the tested cultivars, germination declined as storage temperature increased and, by 200 days, the highest survival rate was obtained with cryostored pollen. Long-term storage of date pollen using an ultra-low temperature (-196˚C) can be used without any deteriorating effect on pollen viability, while room temperature storage significantly reduced pollen germination.
Volume 13, Issue 1 (4-2013)
Abstract
Healthcare providers may need to publish their operational data for consultation as well as to allow more researches. Consequently, a lot of personal specific data with high level of details are publicly available. This data may contain time series, such as ECG. De-identification of time series is not enough to provide the requirement of privacy preservation. It is because, if a few numbers of time series are published, then appearing specific anomalies in them may reveal the sensitive information of an individual. The problem of privacy preserved time series publication is somewhat studied, but the issues of publishing the Ngrams of the time series, especially that of extracted from a small set of time series, are not considered well before. In this paper, we address this problem and define the k-anonymity principle for the Ngram. The proposed schema aims to provide the k-anonymization by repeating the rare n-grams to hide them in the crowd of frequent n-grams. We evaluate our method by using two datasets. Results of experiments show that our method can provide the requested anonymity level with low probability and entropy information loss.
Volume 14, Issue 4 (7-2012)
Abstract
Chrysanthemum (Dendranthema grandiflorum (Ramat.) Kitamura cv. Pattriot) is one of the most important and marketable cut flowers in the world. However, a relatively limited vase life reduces its marketability. The aim of this study was to evaluate the efficacy of salicylic acid (SA) and citric acid (CA) in extending the vase life of chrysanthemum flowers. Therefore, a factorial experiment based on completely randomized design with SA at (0, 100, 200, 300 ppm) and CA at (0, 100, 200 ppm) with 3 replicates and 3 samples (individual flowers) for each replicate, was conducted. Applying SA and CA increased vase life, petal water content (%), initial fresh weight (%) and marketability, significantly. SA treatments increased leaf relative water content (RWC), petal water content (%) and initial fresh weight (%) by 49, 73 and 23 %, compared to the controls, respectively. The highest vase life (21.77 days) was observed for the treatments of SA (300 ppm). The significant increase (300%) in vase life is considered to be due to plant regulating and anti-stress properties of SA and CA. According to the results of this experiment, SA and CA as natural, cheap, safe and biodegradable compounds are suitable alternatives for conventional chemical treatments in order to prolong vase life of cut flowers of chrysanthemum. Commercialization of these compounds for optimum formulations needs further experiments.
Volume 16, Issue 3 (12-2013)
Abstract
More than the half of cancer patients undergo cancer treatments of chemotherapy and/or radiotherapy. Unfortunately treatment with invasive methods occasionally lead to severe side effects. Patients who undergo chemotherapy can be affected by premature ovarian failure, an important cause of infertility. Ovarian tissue cryopreservation is suggested as the only way for preservation of sex cells and fertility preservation in cases of prepubertal girls and women with sterility attributed to chemotherapy, radiotherapy, genetic disorders or specific diseases.
Volume 19, Issue 3 (11-2016)
Abstract
Spermatogonial stem cells are foundation of the male reproductive system. These cells are the only conduit capable of transferring genetic traits from one generation to the next. Isolation and long-term preservation of spermatogonial stem cells for use in inducing spermatogenesis is one technique to preserve fertility in male patients who need chemotherapy. In vitro spermatogenesis is an alternative to achieve this goal. The use of an optimal model of human spermatogenesis is a major step in understanding the physiology and genetic pathways in the male reproductive system. In vitro spermatogenesis is crucial to reducing a complex process into smaller parts for experimentation, manipulation, and deriving cellular and molecular level knowledge. Is it possible to manipulate the paracrine environment and separately evaluate the effects of growth factors. Different in vitro culture systems are used to explore alternatives to spermatogenesis and obtain mature, functional spermatozoa for ultimate use in infertility treatment. In order to present a useful and practical method, this study provides an overview of different methods for the long-term preservation of spermatogonial stem cells and in vitro culture systems used in spermatogenesis.
Volume 20, Issue 142 (10-2023)
Abstract
Considering the high perishability, quality reduction, and nutritional value of the fish during the storage period, the aim study is to investigate the edible coating based on chicken feet gelatin/green walnut skin extract to preserve the physical characteristics, color, and texture properties of Oncorhynchus mykiss fillet during storage in the refrigerator. After extracting gelatin and green walnut skin extract, the coating solution were prepared. The fillets were coated by immersion method. Physical characteristics (moisture), color indices (L*, a*, and b*) as well as textural properties (hardness, springiness, and Cohesiveness) of the fillets were evaluated during 12 days of storage (on days 0, 4, 8, and 12). Variance analysis was performed by Minitab software (version 18). The mean data comparison by Tukey's test is at a 95% confidence level. The results showed significant moisture retention of coated fillets (p<0.05). The L* and a* index of fillets decreased during 12 days of storage. While, the b* index was increased in all samples (p<0.05). The evaluation of the texture of the fillets showed a decrease in hardness and Cohesiveness, but springiness was increased (p<0.05). The coat had significantly higher hardness, Cohesiveness, and lower springiness than the control sample (p<0.05). Increasing the concentration of green walnut skin extract from 500 to 1000 ppm increased the quality of fillets (p<0.05). In general, It can be concluded that edible coating based on chicken leg gelatin/green walnut skin extract effective to increase shelf- life aquaculture industry.
Volume 21, Issue 150 (6-2024)
Abstract
One of the most popular foods consumed worldwide is meat. According to its high protein and moisture content, it is highly susceptible to spoiling itself. Preservatives are therefore necessary to maintain its quality and lengthen its shelf life. The objective of this assessment is to draw attention to a certain technique for extending the shelf life of meat products. This study examined the shelf-life of secondary collagen-containing raw materials treated with varied concentrations of DMSO in terms of pH degree and total ion concentration (TIC). For this purpose, six meat samples were treated with different concentrated DMSO solutions under room temperature and aerobic conditions for 7 days. The outcomes of the experiment proved that meat treated with DMSO had a lower pH, C degrees, and a longer shelf life when compared to the control.
Volume 25, Issue 1 (1-2023)
Abstract
This work aimed to study the antibacterial activity of various Essential Oils (EOs) against food borne pathogens as well as the effect of their incorporation at different concentrations on vacuum-packed ground ovine meat, experimentally inoculated with Listeria monocytogenes, during 12 days of storage at 4°C. In summary, pathogenic bacteria, particularly L. monocytogenes, Salmonella enteritidis and Escherichia coli, showed high sensitivity towards citrus, rosemary, thyme, cinnamon and oregano EOs due to their richness in bioactive compounds. The Minimum Inhibitory Concentrations (MICs) of various EOs against L. monocytogenes and E. coli were about 0.5% for oregano and thymus EOs and 0.7% for cinnamon EO. Besides, addition of EOs at different concentrations resulted in the improvement of biochemical and microbiological qualities of ground vacuum packed sheep meat, during refrigerated storage. High concentrations of oregano (1%) and cinnamon (1.4%) EOs had the most efficient antilisterial activities compared to the control and other meat samples. The treatment of ovine meat with oregano or cinnamon EOs preserved a better content of proteins, a high ratio of PUFAs and a favorable balance between w-6 and w-3 PUFA, resulting in the production of healthier meat.
Volume 25, Issue 2 (2-2023)
Abstract
Temperature treatment during the processing of meatballs is intended to prevent contamination. However, the heat treatment more frequently harms the food structure and loses major nutrients of meatballs. The Arrhenius model has been used to observe the heat-treatment effect on the degradation of food quality. The meatballs samples with edible coating were observed under dynamic temperature storage. The purpose of this study was to use the Arrhenius model to evaluate the heat-treatment relationship on the pH change during dynamic storage conditions: uncontrolled ranging 24 to 31°C, while the studied temperature treatment was ranging between 50 to 90°C for 15 minutes. The results showed an obvious relationship between the heat-treatment aspects for preventing bacteria growth during storage. The evaluation of the Arrhenius model result indicates peak nutrition loss phase transition was found in the temperature treatment range of 83 to 90°C, and the optimum heat-treatment level at 78°C or 148.15 kJ mol-1 for developing packaging or preservation methods.
Volume 25, Issue 2 (2-2023)
Abstract
Nanochitosan composite film containing Nisin (NCH-N) was synthesized by solution cast method. Chitosan nanoparticles were prepared from shrimp shell.Characterizations of the prepared chitosan-nanoparticles were performed using Dynamic Light Scattering (DLS) and Fourier Transform Infrared Spectroscopy (FTIR) technique. The DLS analysis showed that the average size of chitosan- nanoparticles was 84.8 nm. Antimicrobial properties of edible (NCH-N) solution were also tested against pathogenic bacteria such as E. coli, P. aeruginosa, S. aureus, B. cereus, L. monocytogenes, E. faecalis, and eight clinical multidrug resistances K. pneumonia and E. coli. Addition of nisin to film significantly enhances the antimicrobial activity of the film against these tested pathogenic bacteria. This solution was also used as an antimicrobial coating on peaches. Based on the results, the peach coated with the film-forming NCH-N solutions presented a significantly lower amount of microorganisms growth than the uncoated peach, and significantly increased the shelf life of peaches. The color of the peach was not influenced by the films. The similarity of peaks in the spectrum of FTIR films confirms the absence of relevant interaction between the nisin and the polymer. The films were also analyzed by Scanning Electron Microscopy (SEM) to investigate the surface topography. Nanohitosan films were smooth and homogeneous. With the addition of nisin to nanochitosan films, the film became more uniform and homogeneous. The incorporation of nisin into edible nanochitosan films or coatings may be an attractive and convenient method for biopreservation of food.
Volume 25, Issue 2 (2-2023)
Abstract
The present study was conducted to dry apples in a Temperature-Controlled Microwave (TCM) drier under optimum conditions. Drying durations, drying curves, color changes and drying models were analyzed. Within the scope of this study, TCM drying, oven drying, shade and sun-drying methods were experimented. Apples were sliced into four and eight pieces and dried at 50, 60 and 70°C drying temperatures in three replicates. The shortest drying time (30 minutes) was achieved in temperature-controlled microwave drying and the longest drying time (287 hours) was observed in shade-drying method. TCM drying best preserved the color parameters. Lightness and redness values were best preserved with TCM drying at 70°C in four slices and yellowness value was best preserved with again TCM drying at 50 and 60°C temperatures in four slices. Chroma values were best preserved with temperature-controlled microwave drying at 50°C in eight slices. Considering the drying durations and color parameters, TCM drying was identified as the best method for drying apple.
Volume 26, Issue 3 (5-2024)
Abstract
The use of essential oils and new drug delivery systems have been considered two approaches for controlling plant pathogenic fungi. This study aimed to synthesize, characterize, and evaluate the antifungal activity of Solid Lipid Nanoparticles (SLNs) incorporating Mentha×Piperita L. Essential oil (MPE) compared to the free MPE. In the present study, the formulations of SLNs incorporating MPE (MPE-SLNs) were synthesized by high-shear homogenization and ultrasound method, and they were assessed by Z-average diameter, particle size distribution, Zeta potential, leakage stability during 6 months of storage, encapsulation efficacy, and morphological properties of the SLN formulations. The results indicated that the particle size of MPE-SLN formulations was 155.5±4.7 nm with a PDI of 0.156±0.012, a Zeta potential of -15.93±0.87 mV, and encapsulation efficacy of about 88±0.88%. They were physically stable for 6 months of storage. The results also showed that the in vitro minimum inhibition concentration for MPE on the fungal microorganisms, Rhizoctonia solani and Rhizopus stolonifer, were 2,000 and 1,000 ppm, respectively, and for MPE-SLNs it was 1,000 and 750 ppm, respectively. Therefore, the antifungal activity of MPE-SLNs was more significant than MPE, and none of the fungi were susceptible to essential oil-free SLNs. Based on the results, MPE-SLNs can be used for the safe preservation of a wide array of foods and agricultural products.
Volume 27, Issue 2 (2-2025)
Abstract
The primary objective of this research was to reveal the effect of cryotreatment on pollen reproductive ability in vivo by monitoring pollen tube growth in sweet cherry (Prunus avium L.) pistils. The influence of cryotreatment was considered from the context of its interaction with pollinizer genotype, and the possibility for usage of in vivo parameters for assessment of pollen fertility. Pistils of sweet cherry cultivar ‘Regina’ were pollinated with both cryotreated and fresh pollen of ‘Kordia’ and ‘Summit’. Quantitative parameters of pollen tube growth in vivo (pollen tube number in certain pistil parts, pollen tube dynamics, and fertilization percentage) were determined using the fluorescence microscopy method, and the obtained data were analyzed together with those obtained for in vitro pollen performance and fruit set. The research indicated that: (i) Reproductive ability of cryotreated sweet cherry pollen can be estimated by analyzing parameters of its performance in vivo, which should be combined with in vitro test; (ii) Semi- or fully-compatible female recipients, whose sporophytes are supportive for male gametophytes should be used for the assessment; and (iii) The key parameters for in vivo testing are pollen tube number in the upper part of the style and in the ovary, as well as fertilization percentage, i.e. the percentage of pistils with penetration of the longest pollen tube in the nucellus of the ovary on the 10th day after pollination. Therefore, in vivo testing of the pollen reproductive ability after cryotreatment can give answers about pollen quality with valuable credibility, in a maximum of two weeks after thawing and rehydration.
