Journal of Food Technology and Nutrition
Year:2019 | Volume:16 | Issue:3 (63) |Papers Count:11

Introduction: Patulin is commonly produced in apples in unsuitable postharvest or storage conditions and has pasteurization temperature resistance. Some probiotic strains are capable of binding with patulin and remove it from apple juice. The aim of this study is to investigate the effect of adding Lactobacillus acidophilus PTCC1643 and Lactobacillus plantarum PTCC1058 on reduction of patulin content in apple juice. Materials and Methods: Seven variables (probiotic strain, inoculum size, fructooligosaccharide content, inulin concentration, patulin content, ascorbic acid and citric acid concentration) were defined in two levels and Plackett-Burman design was used to evaluate the impact of variables on efficiency of patulin removal. Apple juice samples were pasteurized and were then inoculated and kept in the refrigerator for 42 days. The pH value, titratable acidity, reducing sugars, patulin content and viability of probiotics were analyzed on the first day (week 0) and every week during refrigerated storage. Results: Fructooligosaccharide content and ascorbic acid concentration were determined as more effective variables on patulin removal from apple juice. Inserting 108 and 1010 cfu/ml Lactobacillus plantarum to apple juice can reduce 85. 23% and 91. 23% of initial patulin content, respectively. Conclusion: Both Lactobacillus acidophilus PTCC1643 and Lactobacillus plantarum PTCC1058 have the capacity of PAT removal from apple juice, but percent of removal depends on environment conditions. The highest percent of patulin removal caused during one day after inoculation of probiotic strains.

Introduction: Due to low energy efficiency and prolonged drying time of agricultural products by conventional methods, application of the new techniques such as infrared radiation, has been investigated. Materials and Methods: In this study, in order to dry and increase the shelf life of peach, infrared radiation (IR) method has been employed. The effect of infrared lamp power at three levels 150, 250 and 375 watts, the distance of the samples from the lamp at three levels 5, 7. 5 and 10 cm and at 1 minute intervals for up to 120 minutes on drying of peach were examined. Modeling of process was carried out with genetic algorithm– artificial neural network (GA-ANN) method with 3 inputs (lamp power, distance and time) and1output (weight loss). Results: The results of infrared drying of peach showed that by increasing the lamp power and decreasing the sample distance from the heat source, the drying rate is increased. By increasing the infrared lamp power from 150 to 375 watt, the weight loss is increased from 39. 4 to 87. 50 % and with increase in 250 watt lamp distance from 5 to 10 cm, the weight loss is decreased from 87. 6 to 73. 5 % for the sample. The GA-ANN modeling results showed that a network with 13 neurons in 1 hidden layer with using hyperbolic tangent activation function can predict the weight loss in peach drying using infrared method (R=0. 9991). Conclusion: Sensitivity analysis results by optimum ANN showed that drying time is the most sensitive factor to control the weight loss of peach slides.

Introduction In this study the best method of extracting lycopene from tomato skin, waste and the effect of pectinase enzyme pre-treatment at 2, 4, 6, 8, and 10 ml/Kg concentrations and 30, 60, 90 minutes of effective times for tomato waste and also washing with 94% ethanol at 60 ° C for 5 seconds were studied in order to determine the best method of increasing lycopene purity in oleoresin. Materials and Methods Lycopene extraction was performed at 30 ° C for 16 hours with hexane: ethanol: acetone (1: 1: 2) at ratios of 1: 10 to dried samples with gentle stirring. In order to prevent the lycopene oxidation 0. 05 percent w/w of BHT was used. The effect of oleoresin saponification to increase the purity of lycopene in oleoresin was also studied by propylene glycol and potassium hydroxide 45% (w/w) and deionized water at the concentration of 30%, 10% and 10% oleoresin by weight, respectively. Results The effect of enzyme pretreatment and ethanol and also oleoresin saponification had a significant effect on oleoresin and lycopene extraction and extraction efficiency from tomato waste (P<0. 01). Ethanol treatment significantly increased lycopene purity in oleoresin (P<0. 01). In waste samples treating with 10 ml/kg enzyme concentration at 90 minutes of effective time resulted in highest extraction of lycopene (279. 5 mg/100g oleoresin). Conclusion It has been shown that if saponification is not employed in lycopene extraction from tomato waste the ethanol washing pre-treatments should not be applied.

Introduction The continuous need of human society to extract vegetable oils has led to many studies on the introduction of a more efficient and economical extraction process. The purpose of this study is to determine the effect of ultrasonic and microwave applications as new methods for extracting oil and also studying the physicochemical properties of the extracted oil using two ultrasonic and microwave pre-treatments. Materials and Methods In this study, soybean oil was extracted by ultrasound at three different time intervals of 30, 60 and 90 minutes, and two different temperatures of 25 and 50 ° C in the presence and absence of solvent. Microwave was also applied as heat pre-treatment at three different time intervals of 1, 3 and 5 minutes, and 180 watts in the presence and absence of solvent. Soxhlet method was applied as a mean to extract the oil. The physicochemical properties of the extracted oils were studied. Results In the present study, the ultrasound treated samples had the highest effect on oil extraction efficiency at 50 ° C for 90 minutes by solvent-treated seeds, and this effect was significant (p <0. 05). Ultrasound pretreatment increased oil pigments extraction in comparison with other methods and had less effect on acidity and peroxide values than microwave pretreatment. Conclusion Microwave preheating and ultrasound were superior to Soxhlet's method alone in the extraction efficiency of soybean oil, and ultrasound pre-treatment showed the best results. Additionally, the microwave and ultrasound extraction methods did not have adverse effects on physicochemical characteristics of soybean oil.

Introduction: Nowadays with regard to the harmful effects of synthetic preservatives on consumers' health, the use of natural antimicrobial compounds such as herbal extracts in food preservation is considerably increasing. Doogh or drinking yogurt is a kind of dairy drink made of yoghurt and water which is highly favored in Iran. Staphylococcus aureus is a bacterium causing toxicity in dairy products. The purpose of this study is to investigate the effect of hop and hyssop ethanolic extracts on the prevention of Staphylococcus aureus growth in doogh. Materials and Methods: Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of hop and hyssop ethanolic extracts were calculated. Moreover, the antibacterial activity of those extracts was examined using diffusion disk method, and chemical and sensory properties of doogh were also tested on the 1st, 7th, and 14th days. Results: MIC of hop and hyssop extracts were respectively 12. 5 mg/mL and 6. 25 mg/mL, whereas MBC of those extracts were respectively 25 mg/mL and 12. 5 mg/mL. By adding herbal extracts, acidity of the samples decreased and pH increased (p<0. 05). Moreover, by adding herbal extracts, the scores of sensory properties of the samples decreased (p<0. 05). Among the samples containing herbal extracts, sample containing 12. 5 mg/mL hyssop extract had the best sensory quality. Conclusion: Hop and hyssop extracts had antimicrobial activity against Staphylococcus aureus and they can be used as natural preservatives in doogh. Among doogh samples, sample containing 12. 5 mg/mL hyssop extract can be selected as the best sample regarding its suitable antimicrobial activity and sensory quality.

Introduction: the health benefits of omega-3 fatty acids, as well as the high sensitivity of unsaturated fatty acids to oxidation of fish oil, caused the use of encapsulation of fish oil for enriching food products and drugs. Materials and Methods: this study aims to evaluate the physicochemical properties of nano-encapsulated fish oil, and their oxidative stability during storage at 0 and 24% relative humidity conditions. Emulsion was prepared after sonication with wall materials of maltodextrin (M), modified starch (Hi-cap) and whey protein concentrate (WPC) at the ratio of 1: 4 (oil: wall). Emulsion and nano-encapsulated powder properties including emulsion stability, apparent viscosity, powder moisture, encapsulated coefficient, particle size and morphology of nano-capsules were determined. Results: The lowest amounts of creaming and viscosity were observed in M+Hi-cap+WPC and M, respectively. Moisture content in M+Hi-cap showed the highest value. The lowest and highest particle sizes were measured in M+Hi-cap+WPC and M, respectively. Also, the best encapsulation efficiency was obtained for M+Hi-cap+WPC. SEM photographs showed glass-like sheets of encapsulated materials with the freeze-dryer. During 21 days storage at 0 and 24% relative humidity, the results showed an increase in peroxide and anisidine values. The values were higher at 24% than the 0% humidity, and the best results of oxidative stability were observed in M+Hi-cap+WPC treatment. Conclusion: Based on the findings, relative humidity is an effective factor in the oxidation of fish oil nano-capsules. The use of nano-encapsulation is a practical and effective method for increasing the stability of fish oil for enriching the food and promoting human health.

Introduction: The aim of this study is to investigate the type and amount of phenolic compounds in orange peel essential oil as a source of natural antioxidant and its effect on the oxidative stability of soybean oil. Materials and Methods: The compounds in orange peel essential oil were determined using GC / MS. The antioxidant activity was evaluated by the method of iron regeneration test and DPPH and then the essential oil in four different concentrations (2%, 5%, 10% and 20%) and the synthetic antioxidant TBHQ in the permissible range (0. 01%) were added to soybean oil. Finally, the peroxide and thiobarbituric acid and conjugate diene values were determined. Results: D-Limonene was the predominant compound in orange peel essential oil. One gram of essential oil of orange peel contains 0. 16 mg phenolic compounds based on dry galic acid. According to DPPH and regenerative power, orange peel essential oil showed antioxidant activity, although it was less active than TBHQ. Based on the oven test results as the concentration of essential oil is increased, higher antioxidant activity was observed. There was no significant difference between 5% and 10% concentrations based on the statistical tests, but with an increase in concentration up to 20%, the essential oil was acting as prooxidant (P <0. 05). The result indicated that essential oil had the highest antioxidant activity at 5% concentration. Conclusion: The result indicated that the essential oil of orange peel had stabilising effect on soybean oil during thermal conditions as compared to control sample (P <0. 05). Therefore, it might be employed as a natural antioxidant in foods, particularly those containing edible oils.

Introduction: New packaging has been used as scaffolding to load antimicrobial preservatives in the food industry. In this aspect, the present study is designed and developed to use nanofibers derived from corn protein, which was electronically loaded with antimicrobial combination of essential oil of Zataria multiflora, in order to increase the shelf life of emergency ration food called PM1. Materials and Methods: In this study, zein nanofibers containing Zataria multiflora essential oil, were produced by electrospinning method and its physical and chemical properties were studied. Also antibacterial and antifungal activities of zein nanofibers were investigated. Results: A morphological study of nanofibres containing 3 concentrations of 0, 1 and 3% (w/v) showed that with the addition of essential oil of thyme to the polymeric zein solution a smaller diameter fiber was produced (P <0. 05). FTIR results did not show new bond between the zein and essential oil of the plumeria matrix. In the study of hydrophobicity, the addition of essential oils caused an increase in water absorption and also in the tensile analysis of the samples, the ratio of stress to strain increased with the addition of essential oils (P <0. 05). Conclusion: Nanofibres produced for use as functional food package in food rations have anti-bacterial properties and can prolong the shelf life of these rations.

Introduction: Fresh foods that have been subjected to least processing conditions have become quite popular. The application of edible films and biodegradable materials is a new method to maintain some food products. Materials and Methods: In this study the impact of different concentrations of essential oil of cinnamon and cloves (0, 0. 2, 0. 3 and 0. 4 %) is employed on the film of carboxy methyl cellulose. The tests were concerned with coated meat on 0, 3rd, 6th, 9th and twelfth days. Results: The samples coated with different films during this study were compared to the control. The coated samples showed lower pH, total volatile nitrogen, peroxide value, reactive thiobarbituric acid and total microbial count (p<0. 05). Conclusion: The results indicated that the packed meat with carboxy methyl cellulose and different concentrations of cinnamon and cloves essential oils had effective results concerned with chemical spoilage of the product. The application of 0. 3% of essential oil might be regarded as an optimum concentration for the essential oil.

Introduction: Staphylococcal enterotoxins are members of a family of more than 20 different staphylococcal and streptococcal exotoxins that are functionally related and share corresponding gene sequence homology. These bacterial proteins are known to be mitogen and are responsible for significant human diseases including food poisoning. The aim of this study was to detect the enterotoxin A producing Staphylococcus aureus in profiteroles. Materials and Methods: Sampling was carried out from 50 confectionaries in Karaj from mid-August 2016 to February 2017. Serial dilutions from each sample were prepared and cultured on Baird parker agar. After 48 hours incubation at 37º C, black colonies were selected. Following transfer to blood agar, susceptibility of isolates to oxacillin was determined using disc diffusion method and presence of nuc, mecA and sea genes was checked using PCR. Results: In total, based on culture results 8 out of 50 samples (16%) had Staphylococcus aureus contamination. PCR method results showed the presence of nuc gene in 14 (28%) of the samples, mecA gene and sea gene in 5 (10%), 3 (6%) of the samples respectively. Conclusion: Remarkable frequency of enterotoxin A producing MRSA isolates in different foods and specially profiteroles as an enrichment medium for growth and toxin production of bacteria, is a warning for public health.