جستجوی مقالات مرتبط با کلیدواژه « توت فرنگی » در نشریات گروه « پزشکی »

One of the new techniques in the drying of food is the application of infrared radiation that increases the drying rate, enhanced the final product quality, and decreases the costs of the process.

In this study, drying kinetic modeling of strawberry in an infrared dryer was investigated. The effect of radiation lamp power (150, 250 and 375 W) and distance of the lamp from the sample (5, 7.5 and 10 cm), on drying time, and moisture diffusion coefficients during the drying process of strawberry were evaluated. For measuring the weight of the samples during experimentation without taking them out of the dryer, the tray with samples was suspended on the digital balance. Standard models (Wang and Singh, Henderson and Pabis, Approximation of diffusion, Page, Modified Page –II, Newton, Midilli and Logarithmic) were fitted to experimental data to study the drying kinetics and fitting quality (coefficient of determination and standard error) of them was analyzed.

By increasing infrared lamp power from 150 to 375 W, the drying time of strawberry is reduced by 79.8%. Decreasing the distance of the lamp from a sample from 10 to 5 cm, 40.1 % of drying time is reduced. The effective diffusivity coefficient was increased by increasing heat source power and decreasing distance. Moisture effective diffusivity coefficient of strawberry was between 1.54×10-9 to 13.83×10-9 m2/s.

The effect of radiation lamp power and distance on the drying process of strawberry is significant. Modeling of strawberry drying process showed that all the models led to proper results, but in total, the Page model, compared to other studied models, with the biggest coefficient of determination (R2=0.999) and the smallest error (<0.011), had closer results to the experimental data.

Nowadays, since the pesticide residues in food products can cause adverse effect on the human health, this study was carried out to determine benomyl and diazinon residues in strawberry and also related health risk assessment. In this descriptive study, a total of thirty specimens of greenhouse strawberries were collected from market basket of city of Hamedan. After preparation and processing the samples in the laboratory, benomyl and diazinon residues were determined using spectrophotometer at wavelength 400 nm for benomyl and 245 nm for diazinon in three replications. Also, health risk assessment was computed according to health risk assessment model. The results showed that among the analyzed strawberry samples benomyl was detected in amounts ranging from 0.013 mg/kg to 0.989 mg/kg, and diazinon ranged from 0.01 mg/kg to 1.416 mg/kg. Also, the mean levels of both pesticide residues in strawberry samples were higher than the Maximum Residue Levels (MRL) established by WHO, and also the EU. On the other hand, although the value of the MOET index with 180.51 indicates the cumulative risk of benomyl and diazinon pesticides in strawberries, based on the results of health index, there are no potential health concerns through consuming of strawberry from the study area. Although the results of this study showed that there are no potential health risks for consumers through consuming of strawberry, with increasing use of chemical pesticides for farm and garden products, to achieve food safety, regular monitoring of pesticide residues in foodstuffs is recommended.

Strawberry is a valuable product that has a relatively short storage life. Use of chemical fungicides to extend storage life has been a matter of concern. In recent years, use of edible coatings has been regarded as a safe method in order to replace synthetic coatings. The aim of this study was to increase the storage-life and maintain the quality of strawberry by using edible coatings of whey protein concentrate and Trachyspermum copticum essential oil during a storage time of 10 days at 4 ± 1 ° C and relative humidity of 75 ± 5%. We extracted the essence of the seeds by Clevenger apparatus. Then, the active components of the essence were identified by gas chromatography - mass spectrometry (GC-MS) method. In this study we used edible coating of whey protein concentrate and Trachyspermum copticum essential oil at different concentrations (0.2, 0.4 and 0.6%).Microbial quality )number of molds and yeasts, total microbial count(, physicochemical characteristics (weight loss, acidity, pH, soluble solids, texture firmness, and decay) and organoleptic characteristics were assessed in the experimental group after packing, before storage (at the beginning of storage ) and then 3, 5, 8 and 10 days after storage and compared with those in the control group. This coating significantly delayed the growth of microorganisms. By increasing concentrations of 0.4 and 0.6%, the mold and yeast counts after 10 days of storage reached zero and we found a logarithmical cycle reduction in the microbial load. As well texture firmness, weight loss, and decay percentage significantly decreased in the experimental group compared to those in the control group. On the 10th day, the decay rate was 86% for the control group and 10% for the case group containing 0.6% essential oil. Changes in PH, acidity and soluble solids were not significant. The best organoleptic properties were related to the priming with 0.2% essential oil, which also had a positive effect on the parameters in our study. Strawberry fruit coating with whey protein concentrate and Trachyspermum copticum essential oil can be regarded as a safe and effective way to increase the storage life and quality of strawberry fruit in cold environments

The application of new approaches for packaging valuable fruits such as strawberry has become an attractive research subject. These approaches are used to keep the fruits properties at high quality by increasing storage time.
In this study, two different packing methods (Modified Atmosphere Packaging (MAP) using gas mixture (10% O2, 15% CO2, 75% N2) and Nano Silver Particles were employed. The impact of using these methods on the validity of storage time has been studied. The strawberry packaging using Nano Sliver Particles has been analyzed during 16 days in the poly-ethylene covers with the thickness of 40 microns at the temperature of 50°C. The measures used in the experiments consisted of weigh loss, solid particles in solutions, acidity, pH, fruit tissue hardness, color and the weight percentage of the O2 and CO2 existed in the package.
The results of the two methods on the qualitative properties of strawberry at 5°C and at different time intervals (i.e. 4, 8, 12 and 16 days) indicated that both methods increased the shelf life of the fruit regards to improved sensory characteristics.
The experimental results illustrated that both introduced packaging approaches increased the storage time. The experimental data also indicated that the qualitative characteristics of strawberry, namely fruit color and tissue hardness have increased by using the presented approaches.

Kurdistan is an important province in the production of strawberries in the country. In traditional cultivation due to hand contact and animal fertilizers, soil contamination with pathogenic bacteria such as Staphylococcus aureus and Escherichia coli and other coliforms which can be easily transferred into fruits and vegetables. The aim of this study was to evaluate the contamination rate of Staphylococcus aureus, Escherichia coli and other coliforms in strawberries in Kurdistan.
In a cross-sectional study, 150 samples of strawberries including 90 field crops (Traditional), 30 greenhouses and 30 from ready-made packaging supplied in shops in Sanandaj city were investigated. All the samples were tested according to Iranian standard instruction (No. 1194) for the presence of Staphylococcus aureus, (No. 5272) total count, (No.9236) coliform counting , and (No.2946) for E.coli counting.
In this study sixteen samples (10.66 %) were contaminated with coagulase-positive Staphylococcus aureus, 30 (20%) with Coliforms, and 21(14%) with E.coli respectively. The ready-made packaging samples were more contaminated with Staphylococcus aureus, while farm samples with E.coli.
The results showed that due to use of animal and human fertilizers along with surface water for irrigation the strawberries would be contaminated regardless of type of cultivation. Therefore, proper washing and use of disinfection before consumption are strongly recommended.

Strawberry is a perishable fruit, vulnerable to mechanical damage, microbial spoilage and physiological disorders. Temperature of field and heat of respiration are two important factors affecting the postharvest quality of many fruits. The fruits must be cooled after the harvest in order to improve the quality and shelf-life of the product. The purpose of this experiment is to evaluate the effects of precooling on the microbial and physicochemical properties of two strawberry cultivars during storage.
Immediately after harvesting and packaging of strawberries “Queen Elisa and Kurdistan”, half of the packed was put in the field and the other half was subjected to the precooler. Finaly all of them, were transferred to the cold storage (1 oC, 90% RH). Microbial stability, physiochemical characteristics (weight loss, ascorbic acid, anthocyanin, total phenol contents, antioxidant capacity, titratable acidity, total soluble solids and pH) of precooled and non-precooled strawberries were evaluated every 4 days after harvesting up to 20 days of storage. This experiment was performed in a completely randomized design.
Precooled strawberries significantly showed lower microbial load, weight loss and destruction of ascorbic acid than that of non-precooled fruits up to 20 days of storage (p Application of precooling technique in Queen Elisa strawberry cultivar as compared to Kurdistan strawberry cultivar was significantly more effective in reducing the microbial load, weight loss and loss of biochemical characteristics.

Background and Pesticides are used to control pests in agricultural crops. According to the integrity and permeability status of surface skin of strawberry، pesticides can penetrate and precipitate in the fruit. Thus، the study was performed to assess the level of Organophosphorus pesticide residues together in strawberry produced in Mazandaran province. In this study، 211 strawberry samples were collected in the different cities of Mazandaran province during spring 2012، and the residual levels of malation، diazinon، dursban and etion were analyzed using QUECHERS and GC-MS. The data were analyzed by One-way ANOVA statistical analysis. P< 0. 05 was comprehended as significant. The results showed that the mean residual contents of malation، diazinon، dursban and etion were 4. 58±2. 8 ppb، 37. 2±6. 8 ppb، 6. 07±1. 78 ppb and 2. 67±1. 74 ppb، respectively. Despite the malation and etion، the mean concentrations of diazinon and dursban in strawberry samples were lower than that of Iran standard level. As a result، regarding to the use of large amount of unaccepted pesticides، permanent control of pesticide residues in agricultural products such as strawberry، seems to be necessary.

Strawberries are highly sensitive to fungal agents and، as a result، have a short shelf life. Using chemical fungicides to extend shelf life is a great health concern. Therefore، developing safe methods to control perish ability and maintain quality of strawberries during storage is crucial. Considering the successful application of chitosan in edible coating formulae and its proven antifungal properties due to its nano-particles prompted us to initiate this study aiming at assessing the efficiency of an edible coating based on chitosan nano-emulsion in delaying perish ability، maintaining quality and increasing the shelf life of strawberries. After picking، strawberries were coated with nano-emulsion with particle sizes of 50-100±10 nanometers and containing 0. 5% chitosan as an antimicrobial substance and stored، along with control samples، at a temperature of 4±1℃ and a relative humidity of 70%. At 4-day intervals qualitative indicators، including acidity، soluble solids، texture firmness، weight loss، respiration rate، antioxidant activity، anthocyanin concentration، ascorbic acid and percentage of damage، were determined in three replicates (confidence interval = 95%). Coating strawberries with a nano-emulsion containing 0. 5% chitosan had، in addition to delaying the fruit damage، positive effects on their quality parameters. As compared to uncoated samples، the treated samples were firmner and their weight loss، respiration rate and percent damage were lower. Also،anthocyaninsvandvascorbic acid were better preserved in the coated strawberries than in the control cuncoated sample. Changes in acidity and soluble solids were not considerable. Coating strawberries with a nano-emulsion containing chitosan can be introduced as a safe and effective method to increase their shelf life from 8 days to 20 days (2. 5 times as long) and better preserve their quality.