Food Technology
Maryam Khosravani; Seyyed Moein Nazari; Gholamhasan Asadi
Abstract
Introduction In recent years, increasing consumer awareness of the dangers of consuming high-fat products, sensitivity to proper nutritional patterns and the impact of health factors has increased consumer demand for low-fat or free-fat foods. Scientific researchers have provided a great quantity ...
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Introduction In recent years, increasing consumer awareness of the dangers of consuming high-fat products, sensitivity to proper nutritional patterns and the impact of health factors has increased consumer demand for low-fat or free-fat foods. Scientific researchers have provided a great quantity of evidence between the consumption of high-fat products and the development of diseases such as obesity, hardening of the arteries, chronic hypertension, etc. Fat removal is not an easy task because fat, in addition to nutritional aspects, affect rheological and sensory properties such as mouth feel and texture properties of the final product. Using alternative materials that can be completely or partially replaced fat in the formulation of low-fat products by imitating the properties of fat is great important. Unlike fat, which its high consumption causes many problems; fiber can play a vital role in many of the nutritional, functional, and sensory properties of food products, Some types of fiber act as fat substitutes, while producing less energy, provide a large effect of fat function properties. Increasing consumption of easy-cook meat products such as sausages induced replacement the fat content in the formulation of these products, by fat substitutes such as maltodextrin. The aim of this study was to evaluate the chemical and sensory properties of low fat German sausages produced by maltodextrin. Materials and Methods In this study, 0, 6, 12, and 18% of fat was replaced by maltodextrin in the formulation of German sausage. The chemical and sensory properties were then investigated. Chemical properties including moisture, protein, ash, and fat were accomplished according to the ISIRI standard. Evaluation of sensory properties was done by 5-point hedonic method according to Click et al. (2006). Data analysis was performed using SPSS software in a completely randomized design with a 95% confidence level. Results and Discussion The results showed that with increasing the level of maltodextrin, the amount of moisture, ash, and starch of sausage samples increased significantly. As the concentration of maltodextrin increased, the protein content of the samples decreased. The highest protein content observed in the control sample and the sample contained 6% maltodextrin and in contrary, the lowest protein content was in the sample containing 18% maltodextrin and there was no statistically significant difference between the test samples (p>0.05). Changes in maltodextrin concentrations had a significant effect on the fat content of sausage samples so that with increasing the concentration of maltodextrin in the sausage formulation, the fat content of the samples decreased (p≤0.05). Also, with increasing the percentage of maltodextrin replacement in German sausage samples, the cooking yield decreased significantly (p≤0.05). In the evaluation of sensory properties, it was found that the use of maltodextrin reduced the score in all parameters studied so that the lowest score in terms of color, texture, flavor, and total acceptance of sausage samples was related to sample with 18% maltodextrin replacement. Conclusion The vital role of the effect of dietary fiber on improving and managing the health has been proven by researchers for many years. Due to the need to reduce fat in products such as sausages, which considered as a popular meat product and based on the results observed in the present study, it is recommended to use maltodextrin fiber at the level of 6% as a fat substitute in the formulation of German sausages.
Food Biotechnology
Soheyl Reyhani Poul; Sakineh Yeganeh; Zeynab Raftani Amiri
Abstract
Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity ...
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Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity and color similar to tomato and can probably be effective in preventing spoilage of tomato paste. In addition, astaxanthin has other properties in the field of preventing and controlling diseases and maintaining human health, which justifies its use in food formulations as an enrichment. Since heat, enzyme, acid, etc. treatments are practiced during the production of tomato paste, these factors may change the structure and thus the function of astaxanthin. For this reason, astaxanthin nanoencapsulation is necessary for its use in tomato paste formulation. Materials and Methods In this research, first, astaxanthin was extracted from Haematococcus pluvialis microalgae using the acid-acetone combined method. Then, this pigment was nanoencapsulated using maltodextrin-sodium caseinate coating and the resulting nanocapsules were used together with the pure form of astaxanthin in the formulation of tomato paste. The research treatments were control, tomato pastes containing 3 and 6% astaxanthin (A and B, respectively) and also 3, 6 and 9% nanocapsules carrying the pigment (C, D and E, respectively). These treatments were kept at refrigerator for 28 days and were evaluated (on days 0, 7, 14, 21 and 28) in terms of the total number of fungi, Howard's number (HMC), pH, fungal flora, total bacteria count, amount of lactic acid bacteria and sensory properties. This research was conducted in a completely randomized design. Data were analyzed by One-way Anova and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and Discussion The results showed that the fungi proliferation, total count and lactic acid bacteria were slower than the control during the storage period in the treatments containing astaxanthin and its carrying nanocapsules, and the minimum number of the mentioned microorganisms and Howard's number were related to treatments D and E (p>0.05). Treatments C, B and A were ranked next in this respect (p<0.05). The number of fungi in two treatments D and E from day 0 to 28 varied from 128 to 332 cfu/gr. Also, the Howard number of these treatments was recorded from 18 to 34% in the mentioned time period. However, these two indices in the control ranged from 121 to 792 cfu/gr and 18 to 91%, respectively, during the storage period. The count of total bacteria and the amount of lactic acid bacteria in the control on day 28 were equal to 8.9 cfu/gr and 311 mg/kg, respectively, but these two values were recorded in the E and D treatments on the same day, about 4.8 cfu/gr and 110 mg/kg, respectively. Counting the total number of fungi, bacterias and also Howard's number in control and other treatments showed that the effect of nanocapsules carrying astaxanthin on microbial growth and proliferation is significantly greater than pure astaxanthin (p<0.05). The pH of the treatments varied from 3.9 to 5.8 during the storage period and the most standardized pH (3.9-4.4) was recorded in C, D and E (p>0.05) treatments (p<0.05). The pH of two treatments A and B (p>0.05) was higher than the three mentioned treatments and lower than the control (p<0.05). This finding showed that nanocapsules carrying astaxanthin have a greater effect on controlling the pH of tomato paste than pure astaxanthin during storage at refrigerator (p<0.05). The identification of the fungal flora of the treatments on the 28th day confirmed that two genus of Penicillium and Aspergillus form the main flora of the product. The results of the sensory evaluation of the treatments on day 0 showed that adding astaxanthin and its carrier nanocapsules does not change the color, aroma, taste and texture indicators (subsequently the general acceptance) of tomato paste (p>0.05). On the 28th day, the mentioned sensory indices only in the two treatments D and E were not significantly different from the 0 day, but they changed negatively in the other treatments (p<0.05). Conclusion According to the findings of the present research, astaxanthin extracted from Haematococcus pluvialis microalgae has the ability to inhibit fungal and bacterial spoilage and stabilize the sensory properties of tomato paste stored at refrigerator. This properties were improved by adding nanoencapsulated pigment using maltodextrin-sodium caseinate combined coating. Since there were no significant differences between the two treatments containing 6% and 9% of nanocapsules carrying astaxanthin (D and E) in terms of quality indices and microbial spoilage, therefore, the treatment containing 6% nanocapsules is introduced as the optimal treatment.
Food Technology
Hassan Sabbaghi
Abstract
Introduction: Doughnut is one of the most widely consumed food products in the world due to its suitable organoleptic properties. Today, with the spread of diabetes and lifestyle changes, consumers are paying more attention to the use of sugar-free foods and dietary products. In the bakery products, ...
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Introduction: Doughnut is one of the most widely consumed food products in the world due to its suitable organoleptic properties. Today, with the spread of diabetes and lifestyle changes, consumers are paying more attention to the use of sugar-free foods and dietary products. In the bakery products, sweeteners play an important role in providing moisture, sweetening, texture formation and increasing the shelf life of the final product. Sweeteners intended to replace sucrose should be water-soluble, with enough flavor, and cost-effective. Also, these compounds must also comply with national and international law. Stevia, which is composed of steviol and glycosides, is resistant to heat and pH and is not fermentable. Therefore, its amount should be chosen in such a way that it has no effect on cooking. In contrast, sweeteners containing dextrose and maltodextrin are also heat-resistant and can affect cooking and maintain the quality properties of fermentation. In order to use stevia in products as a substitute for sugar to maintain the formulation ratios, the fillers including low-calorie sweeteners such as erythritol and maltodextrin should be used. Therefore, in this study, the feasibility of producing sugar-free doughnuts as a dietary product was studied using stevia, erythritol and maltodextrin as sugar substitutes. Materials and Methods: The low calorie sweetener blend (stevia, erythritol and maltodextrin) was designed in the first step. It was found that if 46.175 g of stevia and 1997.82 g of erythritol were mixed and homogenized, a mixture would be obtained with sweetness four times higher than sucrose. So, the "sweetener blend" was used for one-fourth of the sugar removal mass and the rest was compensated with filler as maltodextrin. Instead of sugar, this mixture was added with zero ratio (control), 50 (low sugar) and 100% (no sugar) in the formulation of doughnuts and icing. Evaluation of qualitative characteristic including moisture content, oil absorption, density, color and porosity ratio and sensory analysis for doughnuts were performedThe properties of shelf life, including soft tissue assessment, non-absorption of icing and non-growth of mold were also investigated within 14 days. Statistical analysis was performed in a completely randomized design (p < 0.05). Results & discussion: The results showed that replacing 100% sugar in doughnuts was successful in terms of maintaining quality characteristics. The quality properties of doughnuts with 50% replacement (low sugar product) were not desirable. Sugar-free doughnuts had good quality properties (density, porosity, color and shell-life) compared to the control. Replacing the type of sweetener from sucrose to alcohol sugar can increase the moisture level of the product. As the amount of erythritol increased (no sugar sample), the texture became more moist and soft. The oil uptake of sugar-free doughnut did not show significant difference from the control sample and its sensory evaluation was so favorable. Maltodextrin could act as a bulking agent, stabilizer, and thickener agent in a sugar free formulation. Sugar free doughnuts had more brightness (L*) and less redness (a*), and its yellowness (b*) did not show significant difference with the control sample. It can be said that because more air has penetrated in sugar free doughnut the brightness parameter (L*) increased. The use of polyols (erythritol) results in a brighter color in the product, which is due to the lack of participation of polyols in the Millard reaction because they lack a reactive aldehyde group. The early development of the Millard reaction led to changes in hardness. Therefore, replacing reducing sugars with non-reducing compounds such as alcohol sugars in the formulation decreased tissue changes in the direction of hardening. Because of Millard reaction will reduce the sugars available as a plasticizer in the formulation. Sugar free doughnut showed suitable soft tissue during 14 days and indicated that sweetener has an effect on texture because it controls hydration and tends to disperse starch and protein molecules, thus preventing the formation of a continuous mass. No sugar doughnuts showed suitable sensory evaluation about color, taste, smell, texture, and overall acceptance.Therefore, a mixture of no-calorie and low-calorie sweeteners in this study can be used in the preparation of dietary doughnuts.
Messiah Sarfarazi; Mohebbat Mohebbi; Mahdi Saadatmand-Tarzjan; Ali Mirshahi
Abstract
Introduction: Chocolate is a suspension of solid particles, including sugar, cocoa solids and milk powder (depending on the chocolate type) in a continuous fat phase, namely cocoa butter or its substitutes. The solid particles account for approximately 70% of chocolate with the fat constituting about ...
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Introduction: Chocolate is a suspension of solid particles, including sugar, cocoa solids and milk powder (depending on the chocolate type) in a continuous fat phase, namely cocoa butter or its substitutes. The solid particles account for approximately 70% of chocolate with the fat constituting about 30%. Sugar takes up nearly 40–50% of the total solid particles of chocolate, thus influencing its sweetness, particle size distribution, rheological and sensory properties. It is also considered to be a bulking agent and a source of energy which produces 394 kcal/100 g of refined sugar. Therefore, consumers are increasingly becoming concerned with chocolate sugar and calorie content nowadays. This issue can be resolved by replacing sugar with bulk (nutritive) sweeteners and/or dietary fibers. Bubbles are found in many food products, including cakes, chocolates and beverages. Although they do not increase the food nutritional value, they change its textural properties and mouthfeel. Bubbles are normally visible to the naked eye and their mean diameter ranges from 0.05 to 3 mm. X-ray computed tomography is a 3D imaging technique which captures the images of a sample cross-sections. It is used for the non-destructive visualization and characterization of food microstructure. In this method, a series of radiographs of a sample are captured from different angles to be utilized for the 3D reconstruction of the material microstructure. Materials and methods: sugar was replaced with inulin: maltodextrin mixture at ratios of 25:75 (CH2), 50:50 (CH3) and 75:25 (CH4). Carbon dioxide was injected into the samples at 6 bar to produce aerated chocolate. Using X-ray computed tomography, the images of the samples were captured and after processing, the obtained images were segmented using the Chan-Vese method. The properties of bubbles included total volume, diameter and surface to volume ratio. The crystallinity of the samples was determined through X-ray diffraction. The hardness of the chocolate bars was measured using the puncture test. The density of the aerated chocolates was also compared with that of the nonaerated ones. Introduction: Chocolate is a suspension of solid particles, including sugar, cocoa solids and milk powder (depending on the chocolate type) in a continuous fat phase, namely cocoa butter or its substitutes. The solid particles account for approximately 70% of chocolate with the fat constituting about 30%. Sugar takes up nearly 40–50% of the total solid particles of chocolate, thus influencing its sweetness, particle size distribution, rheological and sensory properties. It is also considered to be a bulking agent and a source of energy which produces 394 kcal/100 g of refined sugar. Therefore, consumers are increasingly becoming concerned with chocolate sugar and calorie content nowadays. This issue can be resolved by replacing sugar with bulk (nutritive) sweeteners and/or dietary fibers. Bubbles are found in many food products, including cakes, chocolates and beverages. Although they do not increase the food nutritional value, they change its textural properties and mouthfeel. Bubbles are normally visible to the naked eye and their mean diameter ranges from 0.05 to 3 mm. X-ray computed tomography is a 3D imaging technique which captures the images of a sample cross-sections. It is used for the non-destructive visualization and characterization of food microstructure. In this method, a series of radiographs of a sample are captured from different angles to be utilized for the 3D reconstruction of the material microstructure. Materials and methods: sugar was replaced with inulin: maltodextrin mixture at ratios of 25:75 (CH2), 50:50 (CH3) and 75:25 (CH4). Carbon dioxide was injected into the samples at 6 bar to produce aerated chocolate. Using X-ray computed tomography, the images of the samples were captured and after processing, the obtained images were segmented using the Chan-Vese method. The properties of bubbles included total volume, diameter and surface to volume ratio. The crystallinity of the samples was determined through X-ray diffraction. The hardness of the chocolate bars was measured using the puncture test. The density of the aerated chocolates was also compared with that of the nonaerated ones. Results and discussion: X-ray diffraction revealed that there were many strong peaks in the diffractogram of CH1, which can be ascribed to the high degree of sugar crystallinity in addition to the impurities present in the commercial sugar utilized in this study. In the case of the sugar-free samples, namely CH2, CH3 and CH4, two distinct peaks could be seen at 2θ of about 21° and 23.5°, both of which were much stronger and more defined in the scattering pattern of CH3, demonstrating the more crystalline structure of this sample. It seems that inulin and maltodextrin have physically interacted with each other or with the other ingredients of the chocolate, in particular CBS, which has been more pronounced at the ratio of 50:50. The results of image segmentation showed that the Chan-Vese method, compared with the adaptive thresholding one, was more able to segment the images, because this method does not depend on the image gradient and is especially suitable for the objects with vague edges. The mean bubble diameter of CH1 was bigger than that of the other samples, which could be due to its higher degree of crystallinity, because the crystalline structure of CH1 prevented the gas from being lost leading to the coalescence of smaller bubbles and the formation of bigger ones. In addition, it was observed that the density of the aerated chocolate was higher than that of the unaerated one in all the formulas as a portion of solid particles and fat was replaced with the gas. The results also demonstrated that the sugar-free aerated samples were softer than the corresponding nonaerated ones. However, it was reversed in the case of CH1 which could be ascribed to the presence of sugar in this sample, because in aerated products, solid particles, particularly sugar, form a continuous skeleton and play the same role as fat does in nonaerated products.
Mahsa Faridnia; Ali Mohamadi Sani; Masoud Najaf Najafi
Abstract
Introduction: Natural substances with plant sources are rich in bioactive and useful compounds that promote health and improve the physicochemical properties of food products. Compounds such as antioxidants, polyphenols, pigments, flavors and etc. are among the most important bioactive plant-based compounds. ...
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Introduction: Natural substances with plant sources are rich in bioactive and useful compounds that promote health and improve the physicochemical properties of food products. Compounds such as antioxidants, polyphenols, pigments, flavors and etc. are among the most important bioactive plant-based compounds. Red beetroot is one of the unique plants that are rich in antioxidants, anthocyanins, and red pigmentation. The red pigment of the red beetroot is known as betacyanin, and betanin is the major betacyanin compound in red beetroot. Therefore, due to the red beetroot rich in natural pigments, especially betalains, this plant product has a high potential for use as a natural colorant in food, pharmaceutical, and cosmetic products. However, the restrictions on the use of natural and edible pigments are unstable during processing and preservation. The encapsulation process is one of the effective strategies in the food industry to resolve this problem and to protect bioactive compounds during production and storage. Different methods have been used for encapsulation of bioactive compounds, among which the most prominent ones are freeze-drying, emulsion, spray drying, liposomal, niosome, coacervation, and so on. Freeze drying and spray drying are two of the most widely used and industrial methods for the encapsulation of bioactive compounds, pigments, extracts, pharmaceuticals, and microorganisms. So, the aim of this study was to produce red beetroot pulp powder as a source of bioactive and colorant compounds using spray and freeze-drying processes. Materials and methods: Whey protein isolate (WPI) and maltodextrin with a DE 18-20 in different ratios (100: 0, 75:25, 50:50, 25:70 and 0: 100) as wall materials were used to the beetroot extract encapsulation. The spray drying process of the extracts was carried out at an inlet air temperature of 140 °C and outlet air temperature of 65-70 °C with a pump power of 75%, a compressed air flow of 3.5 m3/h, and a feed flow rate of 5 mL/min. To dry the freeze-dried extracts, each sample was first kept at a temperature of -18°C for 3 h, and then the drying operation was performed in a freeze dryer for 24 h. In all treatments, the Brix feed solution was kept constant at 10%. The produced powders were evaluated in terms of encapsulation efficiency, moisture content, water solubility, and total phenol content. Results & discussion: The results showed that by increasing the amount of WPI to 50% (50:50 ratio), encapsulation efficiency significantly increased (p<0.05). In the spray and freeze-dried samples, the lowest moisture content was observed in the sample treated with 100% maltodextrin. Increasing the maltodextrin ratio significantly (p<0.05) increased the solubility of the powders in water. The evaluation of total phenol content showed that the red beetroot extract powders prepared with freeze dryer had the total phenol content. Also, the powder samples obtained from the ratio of 50:50 maltodextrin to WPI had the highest total phenolic content. Based on the results obtained in this study, it was found that the use of the 50:50 ratio for maltodextrin and WPI resulted in desirable physicochemical properties in the powders obtained by both drying methods. Therefore, due to the high costs of freeze-drying and the results of the present study, it can be concluded that the spray drying method with the conditions applied during this study can be used as an effective and promising method for the production of natural pigments based on red beetroot extract for use in food, pharmaceutical, and cosmetic industries. Hence, using a 50:50 ratio for maltodextrin and WPI as wall materials and drying aid is recommended for the production of red beetroot pulp powder.
Nasrin Malekizadeh; Seyed Hadi Peighambardoust; Aref Oladghaffari; Khashayar Sarabandi
Abstract
Introduction: Sumac is the common name of the Rhus genus, which contains over 250 individual species in the Anacardiaceae family. It is grown in temperate and tropical regions worldwide.Sumac is one of the most common spices used by people of the Mediterranean and Middle East regions. The sumac berries ...
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Introduction: Sumac is the common name of the Rhus genus, which contains over 250 individual species in the Anacardiaceae family. It is grown in temperate and tropical regions worldwide.Sumac is one of the most common spices used by people of the Mediterranean and Middle East regions. The sumac berries contain flavones, tannins, anthocyanins, and organic acids which provide antioxidant, antimicrobial and hypoglycemic activities. Due to spices maintenance problems caused by growth of microorganisms, flavor and color compounds losses, using spices extracts have recently been replaced. Although spices extract is sensitive to light, heat and oxygen and have a lower shelf life in poor storage conditions. Therefore, spices extract microencapsulation has been suggested by researchers. Spray drying is the most common and economical methods of microencapsulation. The aim of this study was to investigate the influence of different concentrations of maltodextrin and inlet air temperature on some properties of encapsulated sumac extract.
Materials and Methods: In the present study, the effects of three different inlet air temperatures (140, 160 and 180°C) and three different maltodextrin (DE=20-18) concentrations (10, 20 and 30%) on production efficiency, moisture content, water activity, solubility, hygroscopicity, wettability and color parameters of sumac extract spray dried powder were investigated. In all experiments, outlet air temperatures, atomizer rotational speed, feed flow rate and atomizer air pressure were kept constant at 80°C, 18000 rpm, 20 ml/min and 4±0.1 bar, respectively.
Results and Discussion: Production yield of the sumac powders varied from 44 to 57%. The addition of maltodextrin increased the product yield by preventing adhesion of the sumac extract on the dryer walls and also increasing the inlet air temperature caused an increase in product yield (P
Elnaz Ghaem far; Seyed Mahmoud Reza Hojjati
Abstract
Introduction: Adding color to Foods can make them more appealing to consumers, to allow consumers to identify what taste to expect from a product, and to protect sensitive flavors from light. Color has always played a vital role in food selection and acceptance, and colorants are added to foods to alleviate ...
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Introduction: Adding color to Foods can make them more appealing to consumers, to allow consumers to identify what taste to expect from a product, and to protect sensitive flavors from light. Color has always played a vital role in food selection and acceptance, and colorants are added to foods to alleviate color lost during processing. Caramel color, from the palest yellow to the deepest brown, accounts for more than 80% (by weight) of all colorants added to the foods we eat and drink (Sengar, et al., 2014).Because of sensitivity of liquid colors to oxidation, light and heat and difficulties in their handling and incorporating, dried pigments have been developed. Microencapsulation is a technique to package materials in the form of micro- and nano-particles. There are different methods for encapsulation in the food industry. Freeze drying which has a long dehydration period, has been used as a simple technique in encapsulating water-soluble essential oils and natural aromas or drugs (Khazaei, et al., 2014). In this work, in addition to liquid caramel color production, encapsulation of liquid color with freeze drying technique through wall materials of maltodextrin and Arabic gum were carried out. The stability of microencapsulated color was then evaluated.
Materials and Methods: Rish baba grape and Kabkab date syrup were obtained from local market. Ammonium chloride, citric acid, sodium hydroxide, tween 80, Arabic gum were purchased from Merck (Germany). Glycine and maltodextrin were obtained from Sigma-Aldrich (USA) and Dextrose Company (Iran), respectively. In this study, the effect of factors such as type of catalyst (ammonium chloride-glycine), concentration of catalyst (0.5-2 molar), the pH of reaction (4-5), reaction time (60-120 minutes) on liquid color intensity of caramel produced from two natural sources of date and grape were investigated based on fractional factorial experimental design. For production of liquid caramel color, grape/date syrup was heated while being stirred to 65ᵒ C. Catalysts were then added to syrup and heated to 110ᵒC. water was added to reaction product and centrifuged. The solvent was removed by rotary evaporator (IKA HB 10, Germany).The resulting caramel color was stored under refrigeration at 4ᵒ C. In order to produce powder of caramel color, wall materials including Arabic gum and maltodextrin were dissolved in distilled water at ambient temperature to obtain 20% total solids concentration and stirred for 30 minutes at 60ᵒC. The mixture of liquid caramel color, tween80, and wall material solution was mixed in a ratio (w/w) of 1:4 (liquid caramel color: wall material) and stirred for 15 minutes. The mixture was then dried in a freeze dryer (ALPHA 1-2 LD PLUS, Germany) for 24 hours. The blank sample was prepared without wall materials and freeze-dried in similar conditions with other samples in 24 hours. Dried materials were collected and stored in brown glass bottles with screwed caps at 4⁰C until analysis. The powders were characterized using TGA/DSC thermogravimetric analysis (METTLER TOLEDO, USA), scanning electron microscopy (SEM) (TESCAN vegar, Czech Republic) and X-ray diffraction (XRD) (Billerica, MA, USA) to confirm the structural and morphological aspects of powders.
Results & Discussion: The results showed that the type of catalyst had no effect on the intensity of the colors and maximum color intensity (0.174 for color produced from grape and 0.15 for color produced from date) was obtained under these conditions: 120 minutes for reaction time, pH value = 4 and catalyst concentration of 2 molar. Results of thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) indicated the increase of thermal resistance by microencapsulation process so that initial decomposition temperature for liquid form, without wall material, with Arabic gum and with maltodextrin for grape source were 114,138,162,185°C respectively and for date source were 113,131, 143, 180°C respectively. Results of Scanning electron microscope demonstrated that size of the powders were 11-55 μm. In conclusion, microencapsulation by freeze drying could be recommended as a suitable method for stabilizing caramel color.
