Journal of food science and technology
Year:2019 | Volume:16 | Issue:93 |Papers Count:18

In current study, the effect of differenthydrocolloids as stabilizer (high bloom gelatin (HBG), low bloom gelatin (LBG), cold water fish skin gelatin (FSG), low methoxyl pectin (LMP) and modified tapioca starch (MS)), was investigated on physicochemical and rheological properties of yogurt in four concentrations. The results showed thatin all samples, except pectin, PH decreased over time, but pHreduction in the sample containing modified starch (MS), was significantly higher than other samples. The LMP sample and the HBG sample had the lowest and highest water holding capacity (WHC) with 57 and 78. 6 percent respectively. At low concentrations, the stabilizers produced loose tissue in yogurt, but at high concentrations all types of gelatin improved the uniformity of yogurt tissue. The highest tissue consistency was observed in the HBG sample. Also, viscosity of the samples increased with the addition of stabilizers, and there was a significant relationship between stabilizers concentration and viscosity. All types of gelatindecreasednumberofgrainsbutstarchsignificantlyincreasedgraininessinallconcentrations(p<0. 05). However FSG showed the best effect and decreased graininess.

In this research a validated and effective method for simultaneous analysis of 24 poly aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometric detector was developed in traditional and semi industrial bread samples. Sample preparation was done based on QuEChERS method and developed method was validated and applied for analysis of bread samples. Matrix effect was evaluated by comparing the slopes of solvent-based calibration curve and spiked calibration curve in blank sample. Among the 24 analyzed compounds, 22 (91%) and 2 (8%) compounds presented the ion enhancement and ion suppression respectively. Therefore spiked calibration curve was used for overcoming matrix effect. In the concentration range of 10-500 ng/g, the calibration curves for each analyte was linear with a determination coefficient (R2) of 0. 990 to 0. 999. The limits of detection (LODs) and quantitation (LOQs) for different PAHs were between 0. 14-1. 49 and 0. 46-4. 91 ng/g, respectively. The mean recoveries obtained for three fortification levels (25, 50 and 200 ng/g, three replicates in each day) in three consecutive days were 86-111% (n=27), and also the average of relative standard deviations (RSDs) of PAHs were in the range of 2. 85-11. 57% with a satisfactory precision (RSD<20%). Analysis of bread samples using the validated method showed that Naphthalene was found in 9 traditional Barbary bread samples (45%) in the range of 46. 34± 1. 89 ng/g and any compounds was detected in semi-industrial samples. All of the obtained positive results were higher than the legal permissible limits (1. 0 ng/g) proposed by the European Union for processed cereal-based foods. The final findings showed that direct flame exposure in gas oven during baking of Barbary bread could produce PAH compounds.

Masske is a traditional butter that is derived from yogurt and used in southern Khorasan, Iran. It is a good source of lactic acid bacteria (LAB). The aim of this study was to investigate the antibacterial effect of the LAB isolates against of Staphylococcus aureus and Salmonella enterica. In the first step LAB isolates were identified by PCR method, and then microdilution method was used to evaluate the antimicrobial activity of the isolates. BLASTing of sequences of 16S rDNA gene with sequences in the NCBI database identified the species include Lactobacillus bulgaricus, Enterococcus faecium, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus delbrueckii and Enterococcus hirae. The results of antimicrobial activity evaluation against Staphylococcus aureus and Salmonella enterica showed that all isolates were able to inhibit the growth of these two pathogens, and their inhibitory percent were 55/46 to 84/49 and 55/46 to 56/55, respectively. Also, the results showed that Lactobacillus plantarum B38, Enterococcus hierae B224, Lactobacillus delbrueckii B37 had the highest inhibitory effect against Staphylococcus aureus (P>0. 05). Lactobacillus plantarum B38 had the highest inhibition percentage against Salmonella enterica (P<0. 05). In addition, it was found that the inhibitory effect of all isolates against Staphylococcus aureus was significantly higher than Salmonella enterica (P< 0. 05). Therefore, lactic acid bacteria isolated from the Masske butter may be used to control the food borne pathogens and food spoilage microorganisms.

The purpose of this study was to investigate the functional properties and production of functional yoghurt using collagen from skin of Sangar. So the collagen was prepared by acid and enzymatic methods and then active microcapsules containing collagen were prepared. Yogurt samples were prepared containing 0% collagen, 1% collagen, 1. 5% hydrolyzed collagen, 50% collagen + 50% encapsulated collagen and containing encapsulated collagen. To compare the mean of data, Duncan's multiple range test was used at α = 5% probability level. The results of collagen samples showed that the lowest reduceing power was observed in normal collagen samples (0. 2%) and the highest in hydrolyzed collagen (5%) (P<0. 05). The least antioxidant activity belonged to normal collagen (0. 2%) and normal collagen (1%). The highest antioxidant activity was observed in hydrolyzed collagen (5%) (P<0. 05). The highest solubility belonged to the hydrolyzed collagen sample (pH=4) and the lowest solubility belonged to the hydrolyzed collagen (pH =10) (P <0. 05). The results of tests of yoghurt samples showed that the pH of sample code 5 was significantly higher on day 1 and pH of treatments of code 2 (containing 1% of normal collagen) and 3 (containing 1 % hydrolyzed collagen) There was a significant lower level of other treatments (P<0. 05). Antioxidant activity of code 4 (containing 50% collagen + 50% capsule) was highest. . On the 14th day, the highest synersis belonged to the control (no collagen) and the least amount belonged to the code 4 (containing 0. 5% collagen + 0. 5% capsule) (P<0. 05). In both days, a significant difference was not found in the color score the taste; odour of the samples was not observed. (P>0. 05) and treatment of code 4 (containing 0. 5% collagen + 0. 5% capsule) was introduced as a superior treatment.

People’ s attitude towards dietary food and nutrition, avoiding the process of gaining weight and emphasizing healthy life on one hand, and the high rate of calorie-generation in fat on the other hand, has persuaded the researchers and producers to decrease the amount of fat in the formulation of the products. Therefore, in this research the possibility of producing low-fat cake is evaluated through considering the elimination of 50% fat, applying tahini meal in three levels of 0%, 10%, and 20%, and replacing consuming water in cake paste with Kombucha drink in three levels of 0%, 50%, and 100%, and thus, observing the features of paste and final product in form of a completely random plan with factorial format (P≤ 0. 05). The results demonstrate that the increasing amount of tahini meal will increase and decrease the viscosity and specific weight of paste respectively; and also increasing the amount of tahini meal increases the amount of specific volume and porosity; and the sample including 20% tahini meal, with replacing 100 Kombucha drinks has the least texture rigidity among others during 1 and 15 days period of time after baking. On the other hand, with increasing tahini meal and Kombucha the amount of L* component of crust decreased and the amount of a* component of the crust in produced samples increased. Eventually, considering the results of the evaluation and experiments on physicochemical and sensory features of the product, observers confirmed the sample with 20% tahini meal with replacing 100 Kombucha drinks as the best sample product. Accordingly, when the characteristics of the best sample were compared with the testifier sample (without additives and oil replacement), the increase of protein, decrease of fat level and peroxide were concluded. Considering the positive results of this project, the low-fat cake enriched with tahini meal and the functional Kombucha drink having qualitative and quantitative nutritional value, can be produced in order to reduce the health dangers of using shortenings.

In this study, the effect of incorporating chia seed roasted flour(MSF) (0-7. 5 %) on moisture content, fat content, total fiber content, antioxidant activity, total phenol content, color, texture and organoleptic characteristics of functional Barbari bread was evaluated. The results showed addition of MSF increased the moisture content, oil and total fiber content, total phenol content and antioxidant activity (17. 9± 0. 9 % to 66. 2 ± 0. 2%) in the samples. While increasing the amount of MSF, the L* value and hardness of the samples was decreased. The organoleptic characteristics of bread containing 2. 5% MSF had no significant different (P<0. 05) with the control. Increasing the replacement of wheat flour with MSF (2. 5 to 7. 5%) reduced the acceptability of organoleptic characteristics of bread. Based on the results of the simultaneous thermal analysis (STA), the enthalpy for control was 4119. 94 (J/g) and for the bread containing 5% MSF was about 4369. 1 (J/g). SEM results showed that the incorporation of MSF created a more uniform structure with smaller cavities in the bread.

Emulsified films based on carboxymethyl cellulose containing macro (ME) and nanoemulsion (NE) of cinnamon essential oil at different concentration were prepared. The dynamic light scattering (DLS) results showed intensified in input energies toemulsion solution led to reducing droplet size (Dz) and heterogeneity (PdI). The microstructure of films were analyzed by scanning electron microscopy (SEM), images showed more different structure due to different stabilization behavior of ME and NE in film forming solutions during drying. Increasing in porosity ofmacroemulsion films and tortuous pathway ofnanoemulsion films, caused to water vapor permeability (WVP) of control filmsfrom 2. 59× 10-9g / m s Pa increased to 4. 43× 10-9g / m s Pa and decreased to 1. 80× 10-9 g / m s Pa in the macro and nanoemulsion films respectively. Plasticizing nature of cinnamon essential oil also higher surface to volume ratio and more interruption interaction between biopolymer chains produced more flexible emulsified films with enhancing in strain at break (SAB) from 53. 56% in control film to 80% and 94. 77% in ME and NE films respectively.

The application of carriers is a proper means of improving the transfer and increasing the bioavailability of bioactive compounds. α-lactalbumin is the second major component of whey protein nutritionally consisted of Trp, Lys and Cys residues which can be employed as nutraceutical carriers. Oleuropein is a bioactive compound with pharmaceutical and antioxidant properties which is found abundantly in olive leaves and at lower levels in olive oil. The current study was undertaken to explore the interaction of α-lactalbumin-oleuropein complex at 25, 50 and 72 ˚ C at pH 7 by using fluorescent, UV and circular dichroism spectroscopy techniques together with molecular docking. The results from UV and fluorescent studies demonstrate that site and binding constant are increased as the temperature increased due to the change in conformation and rearrangement of protein structure. Moreover, circular dichroism results depicted that α-helix and β-sheet structures are decreased and increased respectively as a result of temperature increase up to 72 ˚ C. Ultimately, the molecular docking findings revealed that the best binding energy for complex formation was about-6. 3 kCal/mol and the best binding site was between the α-helix and β-sheet cleft. The findings give us useful information regarding the interaction of oleuropein and α-lactalbumin which can be further used to produce functional foods.

Fruits and vegetables by products enrich from functional components such as dietary fiber and protein. This study aimed to increase the nutritional value of biscuit using grape processing by product as a rich source of raw fiber and sprouted soybean flour as a rich source of vitamin and protein was performed. For this purpose, grape pomace and sprouted soy flour in tree levels (2, 4 and 6%) were replaced individually or composite for wheat flour in biscuit formulation. After cooking and cooling the biscuit, its nutritional characteristics, texture hardness and sensory properties were analyzed. The results showed that the sample containing 6% sprouted soy flour had the highest amount of fat and the sample containing 6% grape pomace had the highest amount of ash. The highest fiber content was in the composite sample containing 3% sprouted soy flour and 3% grape pomace flour. Addition of 6% sprouted soy flour to biscuit increased its protein content but addition of grape flour did not show significant difference in protein content of the product (p <0. 05). In terms of hardness, the sample content containing 6% germinated soy flour and grape pomace had the least firmness and control had the highest firmness (p <0. 05). Evaluation of sensory characteristics showed that the highest score in a sample containing 4% sprouted soybean flour and grape. Overall, the combined samples containing 2% sprouted soy flour and 2% grape pomace had the highest nutritional content and sensory properties. The results showed that the use of grape pomace as a source of dietary fiber and vitamin and sprouted soybean flour as a source of protein and lipid, without an adverse effect on the sensory properties of biscuits to increase the nutritional value of this product.

Pineapple due to nutrients is a desirable option to improve the nutritional value of supplemented products. In this study, due to the increasing importance of production and use of enriched baking products. The effect of size of parts (0. 5, 1 and 1. 5 cm cubic meters) and the percentage of fruits (10, 12. 5 and 15 percent) on the quality of muffin properties were investigated. For this purpose, a completely randomized design was used and the mean of Duncan test was used at 5% level. Increasing the size of parts and percentage of fruit in muffin formulation resulted in decreased specific volume, water activity, pH and fiber and moisture content in the samples compared to the control sample. There was no significant difference between the values of skin color components with control. According to the results of this study, the treatment containing 15% of pineapple fruits with 0. 5 cm cubic meters was introduced as the best treatment and had the highest overall acceptance level for consumers. According to the results, the use of pineapple fruit has been effective in improving the physico-chemical and sensory properties of the muffin samples. Sensory evaluation also showed that adding different amounts of pineapple fruit to muffin formulations significantly reduced the texture index, flavor, color and overall acceptance by increasing the replacement percentage of the produced product compared to the control sample.

In order to increase the per capita consumption of shrimp in Tehran and its proper placement in the household food basket, it is necessary to study the factors affecting the attitude of citizens towards shrimp consumption as well as the factors affecting on decision to purchase. The purpose of this applied-research study also is to investigate and evaluate these factors. For this purpose, by studying internal and external sources, a number of factors affecting consumers' attitudes and their decision to purchase were identified and then tested in the form of assumptions in the target population. The statistical population of the study is the whole city of Tehran which randomly were selected 12 municipal districts for field study with sample size of 500 people. To collect data, a questionnaire was designed according to the assumptions and completed by the consumption society. In order to test the assumptions and investigate the severity and direction of the relationship between their items, a conceptual model was designed and evaluated by structural equation modeling (Lisrel software). In testing hypothetical factors affecting citizens' attitudes were found quality, type of supply and processing, packaging and different beliefs have positive and significant effects on people's attitudes toward shrimp buying and consumption. But the convenience of cooking of shrimp as well as the time and place of consumption had no significant effect on the attitude of citizens. In the following, the results showed that experimental records of consumption, income and price of shrimp are effective on the intention to purchase but the access factor does not have a significant effect on the intention to buy shrimp. Values of effect coefficients showed that among the effective factors on attitude of citizens and the decision to buy, quality and experimental records of consumption are the most effective factors, respectively.

Kefir is a common drink in the Central Asian region and it has beneficial effects in improving the health of consumers. The aim of this study was to investigate the effect of adding different ewe's cheese whey to kefir drink on the survival rate of microorganisms of kefir including Lactobacilli, Lactococci and yeast. After the preparation of kefir drink, the ratio of 0, 5, 7. 5 and 10% ewe's cheese whey was added to kefir drink. The samples were stored in the refrigerator and acidity, pH, number of Lactobacilli, Lactococci, and yeast were determined at 1, 7, 14, 21, and 28 days. The results of the study showed that the highest number of Lactobacilli on 14th and 21th days was 9. 32 ± 30. 0 and 9. 23 ± 0. 30 log cfu/ml, respectively. The highest number of Lactococci in the control and kefir samples contained 7. 5% whey on 21th day was 10. 42 ± 0. 17 log cfu/ml. The highest number of yeast in samples have 0, 5 and 7. 5% whey in the 21th day was 7. 37 ± 0. 17, 7. 87 ± 0. 17, and 7. 48 ± 0. 17 log cfu/ml, respectively. The results of sensory evaluation showed that in the samples of kefir drinks containing 5 and 7. 5% whey produced the highest score in overall utility. According to the results, it seems that kefir dough containing 7. 5% whey can be used to produce kefir drink.

The consumption of extruded snacks has been increased among children. However due to their high content of fat and low nutritional value extruded snacks are contributing to a range of diet related health problems. Therefor they had an appropriate potential for production of functional foods. The objective of the research was to substitute fat used in the production of snacks coating partially by different levels of fat replacer containing native inulin (0-20%) and resistant starch (0-20%) in order to supply low fat flavoring of snacks. Based on mixture design the effect of fat replacers on rheological properties, color and emulsion stability of final products were investigated. Results showed that, addition of resistant starch increased emulsion stability of coating (1. 42). The flow behavior index of samples were investigated by Power-law and Bingham model. Power-law was successfully fitted to the description of flow behavior of coating. Meanwhile, based on rheological properties, all of the samples showed shear thinning behavior and the samples containing higher amount of inulin(20%) and lower amount of fat (80%) had the highest consistency coefficient (2. 219 Pa. Sn) and the lowest and flow behavior index (0. 868). The lightness of product was decreased by increasing fat replacers levels. The lowest amount of lightness belonged to sample containing inulin-resistant starch in 10-10% levels.

The use of synthetic antioxidants has reduced due to its harmful effects on consumer health. The present study was conducted to evaluate the antioxidant properties of Mentha pulegium as a source of natural antioxidants. In order to prepare extracts of Mentha pulegium from a methanol solution, a ratio of 5: 1 was used. The levels of tocopherol and phenolic compounds of the extracts were measured by spectrophotometric methods. Finally, methanolic extract of Mentha pulegium at concentrations of 400 ppm and 800 ppm was added to canola oil, and after heating for 24 hours at 180° C, color index, conjugated dienes value, acid value and peroxide value were evaluated to comparison with the sample containing TBHQ. The results showed that extract at concentration of 800ppm has thermal stabilization efficiency comparable to TBHQ. Therefore, Mentha extracts can be recommended as a potent source of natural antioxidants for the stabilization of canola oil or other unsaturated vegetable oils.

In this study, the complex coacervation of plantago major seed mucilage (PSM) and chitosan (CHI), two oppositely charged polysaccharides, was studied as a function of pH (8. 0-2. 0). Biopolymers concentration 1% and PSM: CHI ratio (10: 90 to 90: 10), according to electrical conductivity (EC) and turbidity analyses. The solution containing 1% biopolymers with PSM: CHI ratio of 85: 15 resulted in maximum complex coacervation at the pHopt 3. 7. The EC of biopolymers solutions increased by decreasing pH. The aforementioned optimum condition resulted coacervates with maximum particles size (7 μ m) and minimum ζ-potential (+5. 5 mV), which were observed as densely agglomerated macro-complexes with highest coacervation yield (87%). These hydrogels be useful for encapsulation and delivery of drugs and (bio-) active compounds.