Masoud Najaf Najafi; Haminreza Shateri; Morteza Kashaninejad
Abstract
Introduction: It can be seen that in most studies published on low fat yogurt, the effects of fat substitutes or process changes, including the homogenization process, have been considered separately. However, process changes, especially changes in homogenization pressure, in addition to the effect on ...
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Introduction: It can be seen that in most studies published on low fat yogurt, the effects of fat substitutes or process changes, including the homogenization process, have been considered separately. However, process changes, especially changes in homogenization pressure, in addition to the effect on yogurt, has also an effective role on fat substitutes such as hydrocolloids and can affect their functional characteristics. Therefore, in order to understand the proper conditions of industrial production, it is necessary to study these changes simultaneously. Due to the importance of low fat yogurt production, the effect of konjac gum, sage seed gum, homogenization rate and fat content on pH, texture, and color of low-fat yogurt was investigated using mixture-process variable experiments and modeling the properties obtained from this experimental method. Materials and methods: To prepare low-fat yogurt, firstly, the cream of 40% fat was added to the milk with 0.05% fat, sage seed gum, and konjac gum were added according to the design treatments and calculated by Pearson square method. The preparation was then heated to 90 °C and cooled down to 45 °C. The starter was then added and incubated in oven until reaching pH = 4.6. The yogurt was cooled down and dispersed in a 100 g cups of polyethylene. Texture analyzer was used for combination of back extrusion and texture profile analysis (TPA) test. The evaluated parameters were: hardness (N), cohesiveness, springiness, gumminess (N), chewiness (N), adhesiveness and adhesiveness force. pH was measured according to AOAC official method NO. 981.12. Results and discussions: The results showed that only the effect of fat content on the 99% level was significant on the pH of the samples, while konjac, sage seed gum, and homogenization rate had no significant effect. By increasing the fat content, the pH of the samples also significantly increased. It is likely that the increase in fat content will reduce the metabolic activity of the starter bacteria and thus increase the pH of the samples. Also, when the fat content of the samples was kept constant (1.75%), increasing the konjac gum and reducing the sage seed gum when the homogeneity of the samples was between 0 and 1200 rpm, the hardness of the samples initially increased and then decreased. When both gums were added at the same level, the hardness decreased indicating the high synergistic effect of these gums at low homogeneity rates. The results of this study showed that only linear effect of fat in 99% level on the adhesiveness force of samples was significant so that by increasing the fat content, the adhesiveness force of the samples increased. Also, the results showed that with increasing the konjac gum and reducing the sage seed gum, the gumminess of the samples first increased and then decreased. The most gumminess sample was in the conditions that both gums were used at the same level, indicating the high synergistic effect of these gums on the gumminess of the samples. The results of color measurement showed that only the linear effect of sage seed gum and the interaction effects of konjac gum-sage seed gum, konjac-gum on homogenization rates of L* samples were significant, and with increasing the level of konjac gum and reducing sage seed gum, L* samples decreased, but with increasing homogenization rates, L* samples increased. In this research, minimization of the fat content and adhesiveness force and maximization of the hardness and cohesiveness was considered as optimization aims. The optimum point calculated as 0.146% konjac gum, 0.053% sage seed gum, 2.42% fat content and 12300 rpm homogenization rate. In this conditio, the responses were: pH=4.5, hardness=3.25 N, adhesiveness force=0.815 N, cohesiveness 0.258 mm and L* 85/18. As a conclusion of this investigation, it could be said that these types of models could be utilized in industries to optimizing the formulation of such product, reducing the cost and increasing the acceptance.
Zohreh Bor bor moradi; Leila Nateghi; Orang Eivaz zadeh
Abstract
Introduction: Flour products are one of the most widely used food products in all over the world. Various types of pastry products derived from wheat flour are including the varieties of soup, plumura, and cane produced by traditional and semi-industrial methods. They are categorized in the bread and ...
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Introduction: Flour products are one of the most widely used food products in all over the world. Various types of pastry products derived from wheat flour are including the varieties of soup, plumura, and cane produced by traditional and semi-industrial methods. They are categorized in the bread and cereal group. The place of wheat- flour dough products, including Ashi noodle in the food basket of Iranian households, is gradually being consolidated. This product is a mixture of wheat flour, water and salt after the treatment process by the machine before being dried. The high consumption of salt in the Ashi noodle leads to the development and progression of hypertension in addition to increasing the risk of cardiovascular disease and, on the other hand, reducing salt leads to problems such as loosening and loss of Ashi noodle drying, as well as the degradation of the strand when boiling. Hydrocolloids or gums are compounds creating consistency and texture and increasing stability, acting as emulsifiers, forming gels, and improving oral sensation. Materials and methods: The general objective of this study was to investigate the effects of adding Farsi gum extract at concentrations of 0.2, 0.4, 0.6, 0.8, 1 and 1.2% based on the weight of flour instead of the salt used in the control group of the Ashi noodle (4.5%) on the rheological properties of Ashi noodle, as well as the evaluating physicochemical, texture, colorimetric, qualitative and sensory properties of low salt Ashi noodle one day after production. Zedo gum is a clear gum leaked from mountain almond trees. Zedo gum is found in white, light yellow, yellow vegetable, orange yellow, red and brown, in various sizes and forms. This gum is also composed of Arabinose and Galactose units. It is also known as Shirazi gum. Therefore, seven treatment groups and a control group were designed according to a completely randomized design. In order to analyze the data, Duncan’s method was used at 95% significance level in mini-fever software. Results and discussion: The results of rheological tests of dough with aloe vera revealed that salt reduction and increased gum significantly (p≤0.05). Those rheological properties of the aqueous pulp which were influenced were including mean curve height, mean curve length, inflation index, and mean surface under the curve, configuration test, and elasticity. The physicochemical results showed that by adding gum and reducing salt content. The amount of moisture was increased and the amount of ash and salt decreased significantly. The results of texture test were determined by texture analysis analyzer. By reducing salt, increasing the concentration of gum, and the hardness of the treatments, the decreasing trend and adhesion rate increased, with the highest adhesion ratio for gum samples 1 and 2. There was no statistically significant difference in the level of adhesion, elasticity and gumminess. The results of colorimetric tests with Hunter lab showed that there was no statistically significant difference in the color components a*, b⃰ and L* between all treatments with the control sample. In evaluating the qualitative characteristics of Ashi noodle, it was shown that by reducing the amount of salt to 3.90% and adding gum to the concentration of 0.6% of the weight of the heterogeneous strands, the weight of the broken and degraded strands showed a decreasing trend compared to the control; and in the concentrations higher than 0.6% gum, these incremental changes showed a statistically significant difference between the samples with 1.2% gum and the other treatments. Moreover, the results of sensory evaluation indicated that there was no significant difference compared to the control sample by reducing the amount of salt to 3.90% and adding 0.6% gum to smell, color, texture and overall acceptance of treatments. The taste score of all treatments did not differ significantly from the control sample. The results of this study showed that the amount of Ashi noodle salinity could be reduced to 0.6%, and instead, gum can be added to it with no effect on the qualitative, textural and sensory properties of the Ashi noodle compared to the control sample.
Hassan Sabbaghi; Aman Mohammad Ziaiifar; Mahdi Kashani-Nejad
Abstract
Introduction: Fruits and their products in the dried form are good sources of vitamins, energy and minerals. However, during the process of drying or dehydration there are changes in quality parameters in dried products. Texture is one of the most important quality attributes of fruits during drying, ...
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Introduction: Fruits and their products in the dried form are good sources of vitamins, energy and minerals. However, during the process of drying or dehydration there are changes in quality parameters in dried products. Texture is one of the most important quality attributes of fruits during drying, reflecting their mechanical and microstructural properties. Apple is perishable fruit. Drying of apple is very important because of High losses are experienced during the seasonal glut. A novel process in food industry is the simultaneous infrared dry blanching and dehydration operation (SIRDBD) with intermittent heating method (radiation at constant temperature) exerted on fruits and vegetables that is known to enhance the quality of the final product. In the food industry, end-products must achieve a compromise between several properties, including sensory, sanitary and technological properties. Prediction of changes in texture during drying could be helpful in a better process control and improvement in overall acceptability of a dried snack food. The change of the elastic or viscoelastic texture of the fresh apples to rigid, fragile and brittle in the apple chips were evaluated by instrumental and sensory methods. Many attempts have been made to describe the viscoelastic behavior of dehydrated fruits and vegetables. Maxwell’s or compression models are limited to homogeneous, isotropic materials. In contrast, texture profile analysis (TPA) is more suitable for heterogeneous biological materials and shows a good correlation with organoleptic evaluation. Typical TPA parameters are including hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness and resilience. In this research, for the first time, textural analysis of dried apple slices by infrared heating at different temperatures and different moisture levels was performed. Finally, the optimum texture and overall acceptance of the product are described according to the instrumental analysis. Materials and methods: Apples (Golden Delicious variety) were purchased from a local market and kept in 0°C±1°C and relative humidity ranging from 90% to 95%. Before every thermal processing, the apple specimens were picked up from the cold storage and then they were put into use after reaching the ambient temperature. The samples were skinned manually and then cut into slices with different thicknesses of 5mm, 9mm and 13mm, all 20mm in diameter. The sliced apples were immediately subjected to simultaneous blanching and infrared drying. The texture of dehydrated apple slices using infrared radiation at three surface temperatures of 70, 75 and 80 °C were studied. The product in three thicknesses was dried to achieve a moisture level of 15, 20 and 25% wet weight basis. Then, texture profile analysis (TPA) was carried out to 50% compression strain using texture analyzer. The sensory evaluation of dried slices was also considered for desire texture (Good mouth feels texture, lack of hard tissue, no shrinkage) and overall acceptance (The final acceptability of the product in terms of total sensory properties including color, texture, flavor and aroma) by 10 professional panelists. For statistical analysis, a completely randomized design (CRD) was used in a factorial form (33) and Duncan test with 95% confidence level. Result & Discussion: The results showed that drying to studied moisture levels reduced the hardness and adhesiveness and increased springiness, cohesiveness, gumminess, chewiness and resilience in comparison with raw apple tissue. Hardness of samples dried at higher temperature was higher due to rapid removal of moisture which might have caused collapse of capillary voids inside the product. Due to shrinkage samples became denser and thus a larger fracture force was to be expected. As water content increases (i.e., higher RH) water plasticizes the cell walls and the material and product becomes softer and more pliable, thus hardness decreases. The increase of hardness could be because the rapid mass transfer that damaged the membrane and cell structure of the fruits during drying. Another important factor responsible for the increase of hardness of finish-dried samples is the low final moisture content when compared with other samples. High temperature drying method enables samples to reach low moisture content at relatively short duration and therefore the product with harder texture was obtained. The maximum value of adhesiveness was observed for fresh apples, which could be attributed to the high moisture and sugar content. Adhesiveness decreased with moisture loss, indicating the availability of free water on the sample surface. A significant decrease in springiness following high-temperature drying could be attributed to the glass transition phenomenon and changes from elastic to plastic behavior. In the period of softening, cohesiveness increased with moisture loss. Hardening caused a decrease in cohesiveness depending on the drying temperature. Gumminess is the energy required to disintegrate a semisolid food to a state of readiness for swallowing. High values of gumminess revealed “firm” and “crisp” with a cell rupture mode of tissue failure and lowest values of gumminess could be classified as “soft”. At the end of drying and with apple hardening, chewiness increased to values equal or above initial chewiness, indicating that a larger amount of energy is needed to masticate dried apples. Resilience had increasing with moisture loss. By increasing the thickness of the slices, the cohesiveness and springiness decreased and hence chewiness significantly decreased. The overall acceptance and desire texture in dried samples was observed at lower water evaporation rate conditions (lower temperatures, lower thickness and higher moisture content). In these conditions, the hardness of apple slices tissue was equal to 695.177 ± 7.685 grams. During drying of the apple, textural behavior was varied from the viscoelastic (higher initial hardness, with cohesiveness, springiness and lower resilience) to elastic and then to plastic or glassy.
Esmail Khazaei; Fakhri Shahidi; Seyed Ali Mortazavi; Mohebbat Mohebbi
Abstract
Introduction: Kiwifruit (Actinidia sp.) has many appealing properties for consumers such as flavor, color, and nutritional content, especially vitamin C. Kiwi seems to be used as one of the major ingredients within the formulation of this category of foods.Microalgae are nutritional and innovative natural ...
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Introduction: Kiwifruit (Actinidia sp.) has many appealing properties for consumers such as flavor, color, and nutritional content, especially vitamin C. Kiwi seems to be used as one of the major ingredients within the formulation of this category of foods.Microalgae are nutritional and innovative natural sources that can be used in the development of novel foods. Among the known species of algae, Chlorella vulgaris and Spirulinaplatensis are common edible microalgae that have no side effects on health of human. The amino acid, carbohydrate, and fatty acid profiles of these microalgae are very similar to those of other food materials. Spirulina is a multicellular filamentous blue-green microalga, which was introduced as generally recognized as safe (GRAS) after being approved by food and drug administration (FDA). Spirulina can also be incorporated into common food preparations such as pastas, biscuit, bread, snack,pastille, candy, yoghurt, soft drink, causing health-promotion that are associated with microalgae biomass.The aim of this study was to investigate the possibility of producing new product based on kiwifruit and its enrichment with Spirulinaplatensis microalgae so that this product could replace common snacks, especially the pastilles containing synthetic colors and flavors, which have increasingly been used day by day despite having a low nutritional value and causing a variety of side effects. The role of pHysicochemical and sensory properties is very important in producing new products which can help producers design the products suitably. Therefore, some of the pHysicochemical properties of the kiwi base pastille were examined in this study, as well as the formulation and enrichment of it with Spirulinaplatensis. Material and methods: The ingredients of the formulations consist of 65% w/w kiwifruit puree, 30% w/w sweeteners (sugar, powdered glucose, invert syrup and sorbitol), 0.25% w/w high methoxyl pectin, 0.5% Agar, 0.5% Guar and Spirulinaplatensis(0, 0.25, 0.5, 1 and 2% w/w) as well.In order to produce fruit pastille based on kiwifruit puree, the kiwifruits were fist washed up, peeled and cut into pieces. Then the pieces were grinded. The prepared puree was mixed with Spirulinaplatensis, hydrocolloids and sweeteners at 70°C with specific ratios. Agar was dissolved in distilled water at 90°C and added to the concerned mixture. Finally, after moderating pH to 3.4 by adding 40 M citric acid and controlling the Brix degree in constant Brix of 45, the mixture was prepared. The mixture was then poured into stainless steel mesh molds with cavity dimensions of 1.2 cm × 2 cm × 2 cm and the molds were kept at 4°C for 2 hours to form the gel. Then the obtained gel was taken out of the mold cavities and the samples were dried at 70°Cfor 6 hours in a hot air drier with 1.5 m/s airflow rate. Then the regarded tests were performed on the dehydrated samples. To measure pH, pH meter (Hana, Portugal) was used. The measurement of mixture Brix was performed by an optical refract meter (Carlze, Germany). The drying process of the samples was conducted in a hot air drier (Soroush Medicine Co. Iran).Moisture, protein, fiber, lipid, ash, vitamin C, calcium and iron elements were measured according to the Iran national standard.Texture profile analyzer (QTS25 CNS Farnell England) equipped with a software was used to determine the textural properties of the samples. Samples were compressed and decompressed in two reciprocating cycles by a round plate cylindrical probe with 3.5 cm diameter, 1 mm/s probe speed and 5 g force to 30% initial height.Histological properties obtained from force-deformation curve are as follows: Hardness, Cohesiveness, Elasticity, Adhesiveness and Chewiness.Sensory test was performed with the judgment of 10 trained panelists. In order to evaluate the samples. A 9-point Hedonic method (1: very undesirable - 9: very desirable) was used. 5 sensory attributes (color, texture, flavor, odor and overall acceptance) were evaluated.SPSS software was used for the statistical analysis of the parameters. Mean of the replicates were compared via the multi-range Duncan`s test at 95% confidence level.In order to pHotograpHy with Scanning electron microscope, initial preparation should perform on all of samples.The obtained sampleswas removed from the templates and were sectioned on a scale of 2×1×1mm. samples were dehydrated in ethanol solution and then dried in a critical point. Then samples with 30 nm of gold/palladium coated and were tested using SEM (model LEQ1450VP) in the maximum voltage of 15 kv. At least four images with magnification of 500, 1000, 2000 and 5000 were prepared in several different areas of the samples.Results and discussion: The obtained results indicated that the effect of Spirulinawas significant on the moisture content and increasing Spirulinaconcentration led to increased moisture content of the product.The results of texture profile analysis indicated that the hardness and chewness was increased, but the cohesivness of samples was decreased when the amount of Spirulina is increased. The amount of protein, vitamin C, total ash, iron and calcium was increased by increasing the amount of Spirulina. SEM microscopic results showed that adding up Spirulina is led to the reduction of the uniformity of sample’s structure and then the gel matrix will be created with a larger pore. Results of sensory analysis indicate that samples containing 0.25% Spirulina have sensory characteristics (color, aroma, flavor and overall acceptability) than other samples.
Behnam Fiyuzi; Mostafa Mazaheri Tehrani; Esmail Khazaei
Abstract
Introduction: Due to the lack of proper harvest, packaging, transport and storage, about 30% of country dates production cannot be directly absorbed into the consumer market and must be exchanged to valuable products in transformation industries.Hydrocolloids are used in fruit snack formulations to create ...
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Introduction: Due to the lack of proper harvest, packaging, transport and storage, about 30% of country dates production cannot be directly absorbed into the consumer market and must be exchanged to valuable products in transformation industries.Hydrocolloids are used in fruit snack formulations to create novel texture, increase stability due to their water-holding capacity, improve texture and have an impact on flavor release and other structural and sensory properties in the respective products. Gelatin is a gel forming hydrocolloid. Xanthangum is a kind of long-chained polysaccharide with high molecular weight. LikeXanthan and guar gums can also interact with some polysaccharides such as gelatin, agar and carrageenan synergistically leading to increased viscosity or gel forming power. This type of synergistic behavior among polysaccharides is commercially valuable, because it creates a novel texture and a more desirable structure.This study on viscosity and textural changes caused by using a mixture of gums in food formulations is important and will affect the cost of various stages of the process.Material and methods: The initial materials containing date(Shahani variety), condensed whey(brix=35) were provided from Asali Mod compony, Xanthan gum from Sigma company. powdered glucose and date were bought from Mashhad bazar.In order to produce gel based on date puree, the date were fist washed up, peeled and cut into pieces. Then the pieces were grinded. The prepared puree was mixed with hydrocolloids and sweeteners at 70°C with specific ratios. The mixture was then poured into stainless steel mesh molds with cavity dimensions of 1.2 cm × 2 cm × 2 cm and the molds were kept at 4°C for 2 hours to form the gel. Then the obtained gel was taken out of the mold cavities and the samples were dried at Environmental drier with 1.5 m/s airflow rate. In this research, the produce of jelly viable products based on date puree by the different rates of gelatin hydrocolloids in two levels (6 and 8%) and Xanthan in two levels (0.25 and 0.75%) and condensed whey in three levels (5, 10 and 20%) was studied. Dependent variables were consisting of moisture content, water activity, PH, Brix, protein, ash, texture assessment and color parameters. In final has done the sensory evaluation.To measure pH, pH meter (Hana, Portugal) was used. The measurement of mixture Brix was performed by an optical refract meter (Carlze, Germany).Moisture, protein and ash were measured according to the Iran national standard.In order to determine the water activity of the samples, equal weights of the samples were grinded and the water activity was measured by a aw meter (Testo model 200, England) at 20°C. Texture profile analyzer (QTS25 CNS Farnell England) equipped with a software was used to determine the textural properties of the samples. Samples were compressed and decompressed in two reciprocating cycles by a round plate cylindrical probe with 3.5 cm diameter, 1 mm/s probe speed and 5 g force to 30% initial height. Histological properties obtained from force-deformation curve are as follows: Hardness, Cohesiveness, Elasticity, Adhesiveness and Chewiness.In order to measure color parameters of samples, three samples were choose randomized from each formulation, and pictures were taken with 90 angle and pictures were saved with IPG format. The other stages of picture processing were done by ImageJ 1.40g software.Sensory test was performed with the judgment of 10 trained panelists. In order to evaluate the samples. A 9-point Hedonic method (1: very undesirable - 9: very desirable) was used. 5 sensory attributes (color, texture, flavor, odor and overall acceptance) were evaluated.This study was triplicated through a completely randomized design. Gelatin hydrocolloids in two levels (6 and 8%) and Xanthan in two levels (0.25 and 0.75%) and condensed whey in three levels (5, 10 and 20%)were considered as the independent variables and a design composed of 12 formulations was created. SPSS software was used for the statistical analysis of the parameters. Mean of the replicates were compared via the multi-range Duncan`s test at 95% confidence level.Results and discussion: The obtained results showed that with increasing of condensed whey decrease the PH formulation but ash, moisture, water activity and the rate of protein in samples significantly have increased. Also effect of Xanthan and gelatin had an increase trend in water activity of samples. Also with increasing every three variables in formulation, brix had an increase trend. According to results with increasing hardness gelatin has increased the chewing and continuity feature of texture but adhesion had a decreasing trend. The increasing of Xanthan formulation led to increase of elasticity, context chewing of gum and decreasing of samples. Colorimetric results in method of Image processing were not significant on none of colorimetric variables. But in generally with increasing hydrocolloids in formulation had decreasing the light intensity and L*had a decreasing process. Sensory evaluate shows samples containing of 20% whey have less general acceptance. Also the samples containing of highest percentage of hydrocolloids allocated to themselves the less of rating flavors and aromas.
Esmail Khazaei; Fakhri Shahidi; Seyed Ali Mortazavi; Mohebbat Mohebbi
Abstract
In this research, the production of a new kiwi- based product by applying kiwi puree, agar (0.25, 0.5 and 1%), guar (0.25, 0.5 and 1%) and other formulation ingredients (kiwi puree, sweeteners and pH modulators) has been investigated. Dependent variables include moisture content measurement, instrumental ...
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In this research, the production of a new kiwi- based product by applying kiwi puree, agar (0.25, 0.5 and 1%), guar (0.25, 0.5 and 1%) and other formulation ingredients (kiwi puree, sweeteners and pH modulators) has been investigated. Dependent variables include moisture content measurement, instrumental texture analysis and sensory evaluations were carried out in a factorial design and the means were compared at significance level of 5 % by Duncan test. The results indicated that guar had a significant effect on the moisture content of final product. Textural properties of the kiwi pastille were influenced by the type and amount of hydrocolloids. Synergistic effects of agar and guar on the textural properties were also observed. While all products were acceptable regarding sensory properties, the samples prepared with 1% agar and 1% guar obtained the highest score.
