جستجوی مقالات مرتبط با کلیدواژه « sodium alginate » در نشریات گروه « صنایع غذایی »

Chocolate is made of cocoa mass and sugar suspended in a cocoa butter matrix (Konar et al., 2016). One of the most important ingredients in chocolate manufacture is cocoa powder, which is a complex blend of proteins, polysaccharides, and lipids (Orkaz et al., 2020)In recent years, the global market of functional foods, especially supplements with probiotics, is expanding rapidly. Probiotics are the live microorganisms that, when administered in adequate amounts, provide health benefits to consumers (Tsuda et al., 2010). The health benefits of probiotics include preventing infectious diarrhea, decreasing cholesterol levels in the blood, reducing symptoms of lactose intolerance, increasing immunity to specific diseases, and acting as an antitumor/anticancer agent. Probiotic efficacy can be enhanced when these microorganisms are integrated into the diet, as interactions with food components can protect microbial cells as they pass through the gastrointestinal tract (Vindeola et al., 2011), influenced by the growing demand for functional chocolates that may help customers improve their health (Orkaz et al., 2020). milk chocolate, in particular, is known to be a source of a variety of physiologically active compounds with significant antioxidant activity, such as flavonoids and polyphenols (Todorovic et al., 2015).

Probiotic strains B. bifidum were obtained from the Persian Type Culture Collection (PTCC), Tehran, Iran. Bifidobacterium bifidum was grown in 18 mL MRS broth, supplemented with 0.05% L-cysteine hydrochloride (Sigma, Sydney, Australia) MMRS (Modified MRS) to provide an anaerobic environment, at 37 °C for 48 h under anaerobic conditions using the Gas Pak system (Anaerocult A, Darmstadt, Merck, Germany). The cultures were transferred into 180 mL MMRS for B. bifidum and incubated under the same conditions. The cultures were then reactivated by transferring 3–4 times in MRS broth and the cells were harvested by centrifuging at 1500 g for 15 min at 25_C (Eppendorf Centrifuge, 5810R, Hamburg, Germany) and washed twice with sterile 0.1% peptone solution. The final cell concentration was adjusted to 1.0 * 109 Cfu ⁄mL (Zomorodi et al., 2010). Preparation of the microencapsulated solution: The whey protein isolated micro-coating solution was prepared according to Tellioghlu harsa & cabuk (2015) method with some modifications. Thus, first a solution of 8% whey protein isolate was prepared and for protein denaturation, it was heated at 80 ° C for 30 minutes and then cooled to ambient temperature. To prepare the alginate coating solution, first a 2% alginate solution was prepared in sterile distilled water and after sterilization (at 121 ° C for 15 minutes) it was cooled. Microencapsulation of microorganisms: The extrusion technique was used to microencapsulate bacteria. After washing, the cultures were suspended in 5 mL of sterile 0.1% peptone solution and mixed with 20 mL of 2% (w⁄ v) sodium alginate solution and 20 mL of 8 % (w⁄ v) whey protein concentrate solution sterilized at 121_C for 15 min. The cell suspension was injected through a 0.11-mm needle into sterile 0.05 M CaCl2 (Merck, Germany). The beads were allowed to stand for 30 min for jellification, and then rinsed with, and subsequently kept in, sterile 0.1% peptone solution at 4_C. After filtering from sterile filter paper, the seeds were transferred to sterile plates and placed in the freeze dryer for 2 days at -130 ° C for drying, and after drying under sterile conditions, they were powdered.

Evaluation of survival of Bifidobacterium bifidum: Bacterial count results for probiotic chocolate increased from 7.33 Cfu/gr on the first day to 6.15 Cfu/gr on the 30th day and to 4.69 Cfu/gr on the 60th day, indicating that the probiotic chocolate retained its probiotic properties until the 30th day(P<0.05). Bacterial count results for microencapsulated probiotic chocolate increased from 6.48logcfu/gr to 6.33logcfu/gr on the 15th day and to 3.5 Cfu/gr on the 60th day, indicating that the microencapsulated probiotic chocolate retained its probiotic properties until the 15th day. Chocolate is one of the products that with increasing of water activity, the amount of damage to the product and the spoilage of the product is accelerated, and therefore it is necessary to pay much attention to the amount of aw. The results showed that probiotic chocolate has a higher water activity than plain chocolate, but not enough to cause probiotic bacteria activity in it (P<0.05). Investigation of acidity changes: The results indicate that the acidity changes for the control sample after 60 days of storage are 1.14 (in terms of oleic acid percentage). This value starts from 0.89 on the first day for microencapsulated probiotic chocolate and reaches 0.95 (in terms of oleic acid percentage) after 60 days of storage, which is not similar to the acidity changes for the unencapsulated sample, which means the trend of acidity changes is not too different for each of the samples. Probiotics remain in the incubator phase in the chocolate-based environment, so no activity occurs that produces lactic acid products that affect acidity. Investigation of pH changes: It is important to study the pH changes of chocolate samples because pH changes are one of the factors affecting product quality, spoilage and its shelf life. The pH values during the storage period for the probiotic chocolate samples show an almost constant trend. Investigation of moisture changes: The results showed that the moisture content of the control sample is higher than probiotic chocolate and microencapsulated probiotic chocolate, which is due to the smaller particle size in the control sample and thus the ability to absorb high moisture. The high moisture content of microencapsulated chocolate compared to the unencapsulated type is probably due to the presence of hygroscopic substances such as whey protein in the bacterial coatings, which have a high ability to absorb moisture and increase the amount of moisture. Investigation of texture hardness changes: Based on the results of texture hardness measurements, the highest hardness was observed in microencapsulated probiotic chocolate (after 60 days) and the lowest hardness was observed in plain chocolate (after 1 day), which could be due to the effects of the materials used to microencapsulation. Investigation of viscosity and yield value changes of chocolate: In this study the results of viscosity measurements show that due to the smaller size in the control sample and thus its ability to absorb high moisture, the viscosity and yield value of the control sample is higher than probiotic chocolate. In addition, microencapsulated probiotic chocolate has a high moisture absorption capacity compared to the unencapsulated type due to the presence of hygroscopic substances such as whey protein in the coating, resulting in higher viscosity and yield value. Sensory evaluation: results show that the probiotic chocolate containing Bifidobacterium bifidum is not significantly different from the microencapsulated type, by the method of sodium alginate - whey protein gel formation, and also the control sample which indicates that the addition of probiotics to chocolate or microencapsulation of probiotic bacteria did not have a significant effect on the desirability and organoleptic properties of chocolate.

There were not seen significant negative effects on physicochemical, rheological and sensory properties of probiotic chocolate, probiotic chocolate and microencapsulated probiotic during the storage time and therefore there is no need to change the technological and device conditions and also purchase additional equipment for probiotic chocolate production.

The musk willow essential oil is volatile and encapsulation can protect them from environmental factors such as, light, oxygen and temperature. In the present research, preparation of sodium alginate-whey protein microcapsule containing essential oil of musk willow was carried out by internal gelation-emulsification method with encapsulation efficiency of 87.31%. The obtained microcapsules were characterized by particle size analyzer, zeta potential analyzer and scanning electron microscope. Encapsulation efficiency, swelling ratio and in vitro release of the essential oil was also investigated in fatty and acidic food simulation conditions. At acidic and fatty food simulation conditions, the complex presented negatively charged, with potential zeta values being 42.25 and 38.11 mV, respectively. The greatest electrostatic interaction occurred near pH 3.0 where the charge approached neutrality, which represents a balance between the biopolymer charges. Microcapsules shrinking in the acidic food simulation (pH=3.0) and expanding in the fatty food simulation (pH=7.0). The release results indicated that the release of musk willow essential oil from the microcapsule in both conditions occurred with a controlled manner and exhibited a slow rate. The essential oil release was found to be best fitted by Hixson–Crowell model (R2=0.993 for the acidic food simulation condition and R2=0.995 for fatty food simulation condition) which implies that a change in diameter of the microcapsule as a function of time. Mathematical modeling of release kinetics shows that musk willow essential oil loaded microsphere release follows by classical Fickian diffusion and erosion/degradation mechanisms.

In recent years, the demand for fried products with lower oil content has increased. Therefore, in this study, the effect of different hydrocolloid coatings including sodium alginate (0.50 and 1.00%), calcium alginate (0.50 and 1.00%), and soy protein isolate (4.00 and 5.00%) on oil absorption and quality properties of eggplant slices during different frying times [0, 90, 180, 270, and 360 seconds] were evaluated. The results showed that the samples pretreated with hydrocolloids had lower moisture loss and oil absorption than that of the control sample. In this regard, among the treatments, calcium alginate (1.00%, with a moisture content of 16.66% based on dry weight and the oil absorption of 0.11 g/g food) and soy protein isolate (5.00%, with the moisture content of 33.66% based on dry weight and the of oil absorption of 0.26 g/g food) had the highest and lowest function, respectively. The moisture content of the fried samples decreased with the frying time increase from 90 to 270 s. Meanwhile, the frying efficiency of calcium alginate coated samples, in all four examined times, was higher than the other treatments, which showed the highest value in 90 s (93.12%). The lowest efficiency was observed in the control sample at 360 s (49.51%). The L* values in the samples coated with soy protein isolate were lower than those of the other samples, which could be due to the increase in Millard reaction. Coating the eggplant samples with calcium and sodium alginate resulted in good sensory parameters for 90 s. Overall, the results of this study showed that the use of calcium alginate coating (1%) can lead to the production of low-fat fried eggplant without adversely affecting the sensory and qualitative properties of the product.

Food additives such as enzymes and hydrocolloids are widely used to improve bakery products. By setting a goal to increase crop volume and increase flour strength, in this study, along with a control sample, Sodium alginate and alpha-amylase enzyme during 8 samples (in different amounts, respectively, alpha-amylase and sodium alginate 75-0, 150-0, 0-150, 0-300, 75-150, 75-300, 150 150, 300-150 mg) were added to the bread dough and then rheological properties were investigated by farinograph and extensograph devices. The results showed that among all treatments, treatment 5 (containing 300 mg of sodium alginate) was the best treatment in the studied factors such as development time, consistency, water absorption, stability, degree of softening, farinograph quality number and tensile strength. Therefore, it is recommended to use 300 mg of sodium alginate hydrocolloid to increase the volume and strength of the flour

Raisin is one of the most nutritious dried fruits and rich in various vitamins, minerals, fiber and antioxidant compounds (Mehraban et al. 2015). Iran is one of the major producers and exporters of raisin in the world. During storage period, raisin turns hard and sticky due to exudates syrup and moisture loss. It has been shown that application of edible coating could be useful to overcome this problem and extend shelf life of this product (Ghasemzadeh et al. 2008). Waxes and vegetable oils have been used to coat raisin (Debiofort et al. 1998) Ayoubi et al (2015) coated raisin with carnuba wax and glycerol monostearate. Also, Ghasemzadeh et al (2008) used edible coating based on starch and pectin to coat raisin. Sodium alginate is a water-soluble linear polysaccharide derived from alginic acid and has been considered as an edible coating due to its low cost, non-toxicity and biodegradability (Danapal and Associates 2012). In the present study, the effect of edible coating based on sodium alginate to maintain the keeping quality of raisins during storage at 25 °C for 6 months has been investigated.

raisin was produced from Seedless Asgari grape variety with the soda oil method. It was coated with sodium alginate at levels of 1 and 2%. After coating, samples were packaged in Zip-kip polyethylene bags and stored at 25 °C for 180 days. Physicochemical (weight loss, brix, pH, total phenol, color and hardness), microbial (total count) and sensory (color, texture, taste and overall acceptability) properties were determined during storage in the first day and 45, 90, 135 and 180 days after starting the storage. The weight loss was calculated from the difference between raisin weight in 45, 90, 135 and 180 days with the initial weight. Brix was measured by a refractometer (Protable VBR model, Switzerland). The pH value was measured by a digital pH meter (3020, Jenway, UK). In order to determine the total phenolic contents, the Folin–Ciocalteu method (Taga et al. 1984) was employed and measurements were done at 765 nm with a spectrophotometer (UNICO 2802, China). The color measurement was done using a colorimeter (TES-135A, Taiwan). Hardness of raisins was determined in a puncture test using a QTS texture analyzer (CNS Farnelll, Essex, UK) equipped with a needle probe (stainless steel cylinder of 2 mm in diameter with a conical needle bit) and a test speed of 60 mm/ min during the test. Hardness was defined as the maximum force to puncture raisin from the top to a 2mm depth (Rolle et al. 2011). To determine the total count, pour-plating method was used in PCA medium and incubation was performed at 37 °C. The sensory evaluation was performed by 5-point hedonic scale (1 most disliked, 5 most liked) by 10 trained panelists. The sensory evaluation of all treatments was carried out during storage time (in the first day and 45, 90, 135 and 180 days after storing). A factorial test in completely randomized design with 3 replications was utilized in this study. Analysis of variance (ANOVA) was performed by using MSTAT-C software. Duncan's multiple range test was used to compare the means at the 5% significance level and the graphs were plotted by Microsoft Excel software.

The results of analysis of variance showed edible coating significantly affected the weight loss. Sodium alginate coating reduced the raisin weight loss. In addition, storage had significant effect on weight loss. The weight loss was gradually increased during the storage period. The results of analysis of variance indicated significant effect of edible coating and storage time on raisin brix. During the storage time, brix increased, while the rate of this increasing in samples coated with sodium alginate was less than the control. The results also showed the effect of edible coating and storage time on the pH of raisins was not significant. During storage, the total phenolic content of raisins was gradually reduced. The edible coating reduced the intensity of this reduction. At the end of the storage period, the most total phenol content was observed in 2% sodium alginate treatment. The results of the color parameters evaluation showed that during the storage time lightness of raisin decreased. In addition, the effect of edible coating on this color parameter was significant (p<0.01). L of 1% sodium alginate treatment was significantly more than the control at 180 days after storing and this significant difference observed in 2% sodium alginate treatment at 45, 90 and180 days after storing. The effect of edible coating was not significant on redness but this color property significantly increased during storage period. It seems that browning reactions caused this color change. Also evaluation of yellowness results indicated sodium alginate coating had not significant effect on this color parameter. Storage caused significant changes in raisin yellowness (p<0.01). During storage time initially b value increased and then decreased. The most lightness and the lowest value of redness to yellowness ratio represent the best color of raisin. Analysis of variance show redness to yellowness ratio of raisin significantly increased during storage time (p<0.01). The edible coating was significantly effective in reducing rate of this change. After 180 days storage, the highest and lowest a/b value were related to the control (1.07) and 2% sodium alginate treatment (0.69), respectively. Observations showed raisin texture gradually hardened during the storage period (p<0.01). According to the results of study, the edible coating has not significant effect on raisin hardness. The data showed edible coating had no significant effect on total count, but microbial growth significantly decreased during storage (p<0.01). Acidity, water activity, inhibitor compounds such as phenolic compounds and some products of non-enzymatic browning reaction of Millard are some factors that inhibit microbial growth in raisins during storage (Zhao and Hall 2008; Bower et al. 2003). Based on the sensory evaluation results, storage darkened raisin color and reduced the color score. Edible coating was effective in preserving the color so that at the end of storage time the color score of coated samples was significantly more than the control. During storage time taste and texture scores significantly decreased. Although the edible coating had not significant effect on these sensory properties. Storing significantly reduced the overall acceptance score of raisin. At the end of the storage period, the overall acceptance score of coated samples were more than the control; However, according to the results of Duncan's multiple range tests only the difference between the overall acceptance score of the control and 2% sodium alginate treatment was significant at 135 days of storage.

Meat and meat products are susceptible to microbial and chemical contamination, and microbial growth and oxidation of fats are major causes of spoilage. The use of films and food coatings, mainly due to their ability to create a combination with the properties of preventing moisture evaporation, oxygen penetration, preserving the taste, smell and color of food, increases their quality and shelf life. Medicinal plants are valuable natural resources that are considered by developed countries today. One of the most important and valuable medicinal plants is lemongrass, which has strong antioxidant and antimicrobial potential due to its phenolic compounds and sulfur-containing substances. In this study, beef minced meat was coated with oral sodium alginate coating containing lemongrass extract (0, 0.5, 1 and 1.5%) and in a 14-day period, the total count of mesophilic and cold bacteria as well as PV, TBA , PH and sensory properties of ground beef were evaluated. In data analysis, the results showed that pH, PV, TBA increased significantly during maintenance (p <0.05). However, oral coating containing 1.5% of lemon extract showed the greatest effect against controlling the increase of pH, PV, TBA and counting of mesophilic bacteria and cold-blooded bacteria during storage. Coverage with different ratios in sensory evaluation affected all sensory properties of the samples. So that the highest general acceptance score was related to the coating with 1.5% of lemon extract. As a result, alginate coating containing lemongrass extract can delay microbial spoilage and oxidation in minced beef and improve the sensory properties of minced meat during refrigerated storage.

Increasing public awareness of the effects of abusing high-fat products has prompted food producers to look for appropriate solutions to overcome this challenge. In this study, low-fat butter was prepared using gelatin and sodium alginate (0, 1, and 2%) and monoglyceride (0, 0.5, and 1%) using response surface statistical method and central composite design. Based on test results of texture, melting point, sensory and color evaluation, the optimal amount of fat substitutes was determined. The results showed that with a 50% reduction in butterfat in the presence of gelatin and sodium alginate, the melting point of low-fat butter samples increased from 20 to 30 ° C. Moreover, the moisture content of the samples decreased compared to the control sample. According to the results, monoglyceride had the greatest effect on the apparent brightness component of butter samples. Still, the addition of sodium alginate and gelatin reduced the brightness (L*) and increased redness (a*). Sensory evaluation of the samples also showed a high score of sensory properties of low-fat butter such as texture softness, spreadability, and product consistency compared to the control sample. The optimization results showed that using 1.58% gelatin, 1.86% sodium alginate, and 0.65% monoglyceride, it is possible to produce low-fat butter with a melting point and acceptable tissue properties along with desirable sensory properties.

In order to investigate the effect of savory extract levels and polysaccharide-based active bio-composite coatings on the shelf life of broiler fillets, 2 separate experiments each with 6 treatments and 3 replications, were designed in a completely randomized design and performed simultaneously. Treatments in experiment 1 included fillet with coating 0 (control), 0.75% or 1.5% of savory extract alone or in combination with 3% sodium alginate coating and in experiment 2, included uncoated fillets (control), containing 1.5% of savory extract, guar coating 0.5% - extract, carboxy methylcellulose coating 1% - extract, guar coating – carboxy methylcellulose and guar coating – carboxy methylcellulose - savory extract. Chemical and bacterial spoilage indices including PV, TBARS and TVB_N were evaluated every 3 days during a 12-day period of keeping the fillets at 4±1oC. The results of experiment 1 showed that in parallel with the increasing the concentration of savory extract to 1.5%, the sodium alginate-extract composite coating reduced the PV, TBARS and TVB_N of fillets (P <0.05). Minimum amount of PV (5.40 ± 0.30 meq/kg), TBARS (1.22 ± 0.00 mg MDA/kg) and TVB_N (26.50 ± 1.35 mg/100g) were seen in fillets containing alginate - 1.5% savory extract composite coating (P <0.05). Also, in experiment 2, the fillets containing guar gum – carboxy methylcellulose - savory extract bio-composite coating have the lowest ​​of PV (5.10 ± 0.33 meg/kg), TBARS (1.10 ± 0.05 mg MDA/kg) and TVB_N (25.30 ± 1.90 mg/100g) at the end of the storage period (P <0.05). Therefore, guar gum – carboxy methylcellulose - 1.5% savory extract bio-composite coating as a new packaging can be used to increasing the shelf life of broiler fillets during refrigerator storage (4±1oC).

The most important way to keep shrimp is freezing. But this technique may change the quality of the product at the end of the period, depending on the method of freezing, temperature fluctuations, freezing rate. On the other hand, some consumers tend to consume non-frozen shrimp (refrigerator temperature). Also the use of chemical preservatives raises concerns for consumers because they are harmful. Therefore, it is necessary to study about the use of preservatives that are both natural and able to maintain shrimp quality in a short period of time under non-freezing conditions. The present study was carried out to evaluate and compare the performance of three coating of soduim caseinate- thyme, soduim alginate- thyme and gelatine- thyme in preserving the chemical and microbial properties of Litopenaeus vanamei fillets at refrigerated temperatures (4±1ºC).

Fresh shrimp fillets from Gomishan (Golestan province) was transferred to the laboratory after 3 hours in ice containers and stored under appropriate conditions after being cut, peeled and washed. After preparation of the films, shrimp fillets were coated with Immersion method and were stored at refrigerator temperature in the form of four treatments of 1 (fillet, control), 2 (fillet + sodium alginate 4% - thyme 1.5%), 3 (fillet + sodium caseinate 4% - thyme 1.5%) and 4 (Fillet + gelatin 4% -thyme 1.5%). In order to study the quality properties of shrimp fillets and to compare the antioxidant and antibacterial power of films, PV, TVN-B, FFA, pH, aerobic mesophilic and psychrophilic bacteria were measured for treatment at 0, 3, 6 and 9 days.

The use of these three types of coatings was able to preserve the quality of fillets until the end of the period in refrigeration temperature. But in general and especially in the final days, the fillet coated with sodium alginate-thyme showed significantly lower values in all of chemical and microbial indices than two more covers (p<0.05). In addition, the results indicated that the antioxidant and antibacterial power of sodium caseinate- thyme coating was significantly higher than gelatin- thyme coating, especially in the final days (p<0.05). It should be noted that although the control sample was at standard level in term of qualitive indexes in days 0 and 3, but the most of chemical and microbial indices of this treatment exceeded the allowed limit in the end of maintenance days.

According to the results, all three types of coatings used in the study were able to maintain the chemical and microbial properties of the fillets at the standard level until the end of the storage period. However, the combination of sodium alginate and thyme was more potent and efficient in maintaining shrimp fillets quality than caseinate-thyme and gelatin-thyme coatings (in less than 10 days at refrigerated temperature).

By definition, value-added products are a set of products that are prepared from raw food using various kinds of human or mechanical processing, which are different from their raw food in terms of shape, texture, taste, and smell. The battered and breaded products are among the value-added products, which constitute a wide part of the market for ready-to-eat foods. As indicated by the volumes of international trade in these products, the taste and convenience of preparing these products are favored by most consumers (Venugopal 2006). Breaded shrimp is a product that is first fried in oil after coating (predusting, battering and coating with breadcrumbs), and then it is packaged and stored after freezing. Thus, the consumer only accomplishes the final cooking step, which includes frying in the oil. The poor adsorption of the coating at the food surface leads to a sharp drop in the quality of the product. So, the predusting step is performed to prevent this problem. Predusting involves the use of a soft and dry substance that is applied to the wet surface of the food before further coating, and it reduces the gaps between the coating and the food surface and it can be used as a good flavor carrier by adding spices to it (Albert et al., 2009). The battered and breaded products absorb oil equal to 15-30 percent of their own weight during the initial frying process. Consequently, it has caused the consumers to be concerned about their health, obesity and cardiovascular condition due to the high amount of oil in these products. These concerns can negatively affect the battered and breaded products’ marketing (Venugopal 2006). The ability to form hydrocolloid gels, along with their natural hydrophilic properties, enables them to prevent the absorption of oil into battered and breaded products (Fiszman and Salvador 2003; Sanz et al., 2004; Akdeniz et al., 2006; Chen et al., 2008). For example, Pawar et al. (2014) evaluated effects of hydrocolloids including HPMC, carboxymethyl celluloses and xanthan on the oil uptake of kachori in deep frying. Due to the importance of reducing oil absorption and maintaining the quality of breaded products in public health, this study has examined the effect of sodium alginate, carrageenan and hydroxypropyl methylcellulose hydrocolloids in the composition of predust of breaded shrimp on chemical compounds and sensory characteristics.

To prepare the breaded shrimp, the frozen shrimps were taken out of the freezer, two hours before being used and defrosting was performed in the air. Wheat flour was used in the initial predusting phase. The batter was prepared according to the formula of Fiszman and Salvador (2003), which contains 75% wheat flour, 24.5% corn flour, and 0.5% salt. The dry ingredients and water were mixed in a ratio of 1 to 1.4 for 3 min by using a blender and the breadcrumbs were used for making them breading. To prepare the breaded shrimp, the samples were first predusted and then battered in each treatment, and after dripping the extra batter for 30 seconds, they were ultimately coated with breadcrumbs. Once the coating was accomplished, the samples were fried in sunflower oil in a fryer at 190 ºC for 30 seconds by using a deep frying method so as to keep the product in shape. Then, in order to remove the extra oil, the samples were suspended for 2 minutes, and after cooling the samples to the ambient temperature, the replicates of each separate treatment were packed in zip lock packages and stored in a freezer at -20 ºC until the experiments were performed. After frying of each treatment, the oil was changed and the inner frying pan was washed and completely dried to fry the next repetition. All experiments were performed in 3 repetitions. 10 different treatments, including replacement of 0.5, 1, and 1.5% of hydrocolloids with the initial amount of wheat flour in the batter formulation were prepared. AOAC (2000) method was used to measure the moisture and ash. The amount of protein and fat was also calculated by using Parvaneh method (1377).  The sensory assessment, including color, odor, taste, texture, appearance, and overall acceptance, were applied by 10 trained examiners (students of the food industry within the age range of 20-23). For sensory evaluation, a five-point hydraulic system (5: very good, 4: good, 3: medium, 2: bad, 1: very bad) was used. The examiners were asked to rinse their mouths with water after eating each sample. Means were compared with an analysis of variance (ANOVA) followed by Duncan test to determine among means at p < /em>≤ 0.05 level.

The findings indicated a significant difference between the treatments (p < /em><0.05). By evaluating the findings related to the results of chemical compounds (moisture, ash, fat and protein), the treatments associated with various levels of sodium alginate can be considered as treatments that have the best performance in maintaining moisture and reducing fat. Protein in the samples containing carrageenan had the highest value and the control had the lowest value. Also, the highest and lowest ash levels were belonged to different levels of sodium alginate and carrageenan, respectively. Evaluation of sensory indices (odor, taste, shape, texture, color, and overall acceptance) indicated that there was no significant difference between treatments (p < /em><0.05).

In general, according to the results of chemical compounds and sensory evaluation of the treatment, 0.5% sodium alginate is presented as the most suitable treatment for adding to the predust of breaded shrimp. In the end, after sodium alginate treatments, the results of 1.5% carrageenan and 0.5% hydroxypropyl methylcellulose had proper and not very good and significant performance, respectively.

Formation of nanocomposites in biopolymer coats can provide a new opportunity not only to improve the properties but also to reduce the price of these products. Also, nanocomposites, increase the efficiency of natural antibacterial materials. In order to investigate the antioxidant and antimicrobial effects of lemon grass extract and the amount of nanoclay on the efficacy of alginate-nanoclay composite coating of chicken fillet refrigerated storage, an experiment was performed in a completely randomized design with 6 treatments including alginate (2%) – nanoclay (1.5 and 3%) nanocomposite coating, without and with levels of 1.5 and 3% alcoholic extract of lemon grass and 3 replicates each treatment during 9 days. Results showed that contribution of nanoclay in the structure of nanocomposite coating was affected on its performance. Enrichment of alginate-nanoclay nanocomposite coating with lemon grass extract, added to its efficiency. Applying 3% of lemon grass extract in nanocomposite coatings, especially when using 3% nanoclay, significantly (p<0.05) reduced the number of psychrophilic bacteria, tiobarbitoric acid index, free fatty acids and total volatile nitrogen compounds and increased chicken fillets water holding capacity during refrigerated storage. The contribution of nanoclay in without extract nanocomposite coating, did not significantly affect the number of psychrophilic bacteria at the end of the storage period. In general, the efficacy of alginate-nanoclay nanocomposite coating in increasing the shelf life of chicken fillets in refrigerated conditions depends on the appropriate contribution of nanoclay and enrichment with the appropriate concentration of lemon grass extract.

By definition, value-added products are a set of products that are prepared from raw food using various kinds of human or mechanical processing, which are different from their raw food in terms of shape, texture, taste, and smell. The battered and breaded products are among the value-added products, which constitute a wide part of the market for ready-to-eat foods. As indicated by the volumes of international trade in these products, the taste and convenience of preparing these products are favored by most consumers (Venugopal 2006). Breaded shrimp is a product that is first fried in oil after coating (predusting, battering and coating with breadcrumbs), and then it is packaged and stored after freezing. Thus, the consumer only accomplishes the final cooking step, which includes frying in the oil. The poor adsorption of the coating at the food surface leads to a sharp drop in the quality of the product. So, the predusting step is performed to prevent this problem. Predusting involves the use of a soft and dry substance that is applied to the wet surface of the food before further coating, and it reduces the gaps between the coating and the food surface and it can be used as a good flavor carrier by adding spices to it (Albert et al., 2009). The battered and breaded products absorb oil equal to 15-30 percent of their own weight during the initial frying process. Consequently, it has caused the consumers to be concerned about their health, obesity and cardiovascular condition due to the high amount of oil in these products. These concerns can negatively affect the battered and breaded products’ marketing (Venugopal 2006). The ability to form hydrocolloid gels, along with their natural hydrophilic properties, enables them to prevent the absorption of oil into battered and breaded products (Fiszman and Salvador 2003; Sanz et al., 2004; Akdeniz et al., 2006; Chen et al., 2008). For example, Pawar et al. (2014) evaluated effects of hydrocolloids including HPMC, carboxymethyl celluloses and xanthan on the oil uptake of kachori in deep frying. Due to the importance of reducing oil absorption and maintaining the quality of breaded products in public health, this study has examined the effect of sodium alginate, carrageenan and hydroxypropyl methylcellulose hydrocolloids in the composition of predust of breaded shrimp on chemical compounds and sensory characteristics.

To prepare the breaded shrimp, the frozen shrimps were taken out of the freezer, two hours before being used and defrosting was performed in the air. Wheat flour was used in the initial predusting phase. The batter was prepared according to the formula of Fiszman and Salvador (2003), which contains 75% wheat flour, 24.5% corn flour, and 0.5% salt. The dry ingredients and water were mixed in a ratio of 1 to 1.4 for 3 min by using a blender and the breadcrumbs were used for making them breading. To prepare the breaded shrimp, the samples were first predusted and then battered in each treatment, and after dripping the extra batter for 30 seconds, they were ultimately coated with breadcrumbs. Once the coating was accomplished, the samples were fried in sunflower oil in a fryer at 190 ºC for 30 seconds by using a deep frying method so as to keep the product in shape. Then, in order to remove the extra oil, the samples were suspended for 2 minutes, and after cooling the samples to the ambient temperature, the replicates of each separate treatment were packed in zip lock packages and stored in a freezer at -20 ºC until the experiments were performed. After frying of each treatment, the oil was changed and the inner frying pan was washed and completely dried to fry the next repetition. All experiments were performed in 3 repetitions. 10 different treatments, including replacement of 0.5, 1, and 1.5% of hydrocolloids with the initial amount of wheat flour in the batter formulation were prepared. AOAC (2000) method was used to measure the moisture and ash. The amount of protein and fat was also calculated by using Parvaneh method (1377).  The sensory assessment, including color, odor, taste, texture, appearance, and overall acceptance, were applied by 10 trained examiners (students of the food industry within the age range of 20-23). For sensory evaluation, a five-point hydraulic system (5: very good, 4: good, 3: medium, 2: bad, 1: very bad) was used. The examiners were asked to rinse their mouths with water after eating each sample. Means were compared with an analysis of variance (ANOVA) followed by Duncan test to determine among means at p≤ 0.05 level.

The findings indicated a significant difference between the treatments (P<0.05). By evaluating the findings related to the results of chemical compounds (moisture, ash, fat and protein), the treatments associated with various levels of sodium alginate can be considered as treatments that have the best performance in maintaining moisture and reducing fat. Protein in the samples containing carrageenan had the highest value and the control had the lowest value. Also, the highest and lowest ash levels were belonged to different levels of sodium alginate and carrageenan, respectively. Evaluation of sensory indices (odor, taste, shape, texture, color, and overall acceptance) indicated that there was no significant difference between treatments (P<0.05).

In general, according to the results of chemical compounds and sensory evaluation of the treatment, 0.5% sodium alginate is presented as the most suitable treatment for adding to the predust of breaded shrimp. In the end, after sodium alginate treatments, the results of 1.5% carrageenan and 0.5% hydroxypropyl methylcellulose had proper and not very good and significant performance, respectively.

Macroalgae are source of many polysaccharides. Based on their pigments content they are divided into brown, green and red algae having specific polysaccharide contents. Among them, brown algae (Phaeophyceae) are source of alginates and/or fucans or fucoidans (Percival and McDowell 1990, Torres et al., 2007). Alginates are anionic polysaccharide that existences in mixer of salt forms (Na+, Mg2+ and Ca2+) in cell walls of brown algae makes the tissues flexible and strong. They consist of (1,4) linked β-d-mannuronic acid (M) with 4C1 ring conformation and a-l-guluronic acid (G) with 1C4 ring conformation, the two uronic acids being in pyranosic conformation(Pawar and Edgar 2012, De Sousa et al., 2007). They offer three varying sequences identified as the blocks MG consisting of nearly equal proportion of both monomers with a high number of MG (or GM) dimmers, the blocks GG and the blocks MM (Haug and Larsen 1962). M/G ratio, length and distribution of sequences depend on the algae species but also on their growth conditions and geographic origins. It also determines the chemical and physical properties of alginates (Karaki et al., 2013). Indeed, their gelling properties are dependent on guluronic acid content and explained by the structural features of GG blocks where selective alkaline earth metal multivalent cations and notably Ca2+ take place by chelation. This phenomenon is known and explained as the “egg-box” model. The formed gel is not soluble in water. However, sodium alginate is a water-soluble polymer having generally pseudo plastic properties in solution (Draget and Taylor 2011). Polysaccharides have wide range of pharmacological activities and some of them are considered as antitumor, antihypertensive, immunomodulator as well as antioxidant agents. Their radical scavenger’s role can be used to inhibit oxidative damage in foods and improve their nutritional quality (Venugopal 2011, Yang et al., 2011).

Twenty-five gram of dried algae (Nizamuddinia zanardinii) was soaked under steering at room temperature for 24 h in 800 mL of 2% (v/v) formaldehyde to remove phenolic compounds and pigments. After that, the insoluble fraction was washed 3 times with MilliQ water and supplemented by 800 mL of 0.2 M HCL before to be incubated at different levels(25-60°C) for different extraction time periods(0.5-3 h) under stirring (250 rpm).After optimizing of acidic step, the suspension was then centrifuged (10000 g for 20 min at 20°C) and pellets with alginic acid were washed 3 times with MilliQ water before to be socked in a range from (2-4 % (w/v)) Na2CO3 solution for different levels (2-4 h) at different extraction time periods (60-90 °C). The mixture was centrifuged (10000 g for 30 min at 20°C) and the supernatant was precipitated with 3 volumes of ethanol 96 % (v/v). Pellets containing sodium alginate were dissolved in MilliQ water and precipitated with ethanol as described above. This step was repeated two times before to collect and freeze dried the sodium alginate. Response surface methodology (RSM) was used to study the effect of extraction temperature; X1 extraction time; X2 for acidic step and concentration; X1 , extraction time; X2,; extraction temperature X3 for alkaline step. A D-optimal design was employed for designing experimental data using Design-Expert 10.0.3 trial software (Stat-Ease Inc., Minneapolis, MN, USA).

Both temperature and time factors have a significant effect on the extraction efficiency and the effect of temperature on extraction efficiency is higher than the effect of time in acidic step. There is also a significant interaction between the two variables of temperature and time. The extraction temperature had an increasing effect on alginate extraction efficiency. Chloridric acid disrupts the cell wall and releases alginate and also converts alginate salts in the cell wall into arginic acid. Increasing temperature causes further cellular breakdown and alginate extraction efficiency increases. With increasing time, the extraction efficiency increased. This increase can be due to the fact that the acid needs time to penetrate the cell wall, and as the time increases, the permeability increases, resulting in the extraction efficiency, so that the permeability is complete and the highest efficiency is obtained and After that, the extraction efficiency remains constant and even due to the long-lasting effect of acid, it causes de-polymerization and decreases the extraction efficiency. Increasing temperature increased the effect of time factor, meaning that the interaction of temperature and time had a significant effect on extraction efficiency. At low temperatures, the effect of time on the extraction efficiency is low because of the breakdown of the cell wall, but at higher temperatures, which contribute to the thermal breakdown of the cell wall, the effect of time variation is more evident. In alkaline step the effect of concentration on extraction efficiency was considered as a quadratic equation and as interaction with extraction time. By increasing the concentration of sodium carbonate, the extraction efficiency increases with an ascending slope. In other words, the amount of efficiency increases with an increase in direct concentration. Sodium carbonate causes the sodium substitution in carboxylic acid arginine groups and sodium alginate salts are obtained. Therefore, increasing concentration results in more calcium ion replacement and alginate extraction efficiency increases. This increase in extraction efficiency is increased to the extent that all carboxylic groups are replaced by sodium ion, and after that the extraction efficiency remains constant, and even due to the high concentration and de-polymerization of the alginate, it reduces the extraction efficiency. With increasing time of extraction with sodium carbonate, the extraction efficiency decreases with a second order gradient. Sodium ion has been completely replaced in argonic acid groups during the initial extraction hours, and if the extraction time is increased due to the prolonged contact, sodium alginate is obtained with an excess of sodium carbonate which has an alkaline pH and because of the adverse effect of this pH Extraction efficiency is reduced. The effect of temperature on extraction efficiency was considered as a first-order equation and as interaction with extraction time. As the temperature rises due to breaking of the bonds that may lead to the separation of sodium ions and also cause de-polymerization of the alginate, the extraction efficiency decreases.

Chloridric acid disrupts the cell wall and releases alginate and also converts alginate salts in the cell wall into alginic acid. the acid needs time to penetrate the cell wall. The results showed that in acidic step temperature and time are two major effective factors on yield and quality of extracted alginate. Sodium carbonate causes the sodium substitution in carboxylic acid arginine groups and sodium alginate salts are obtained. Sodium ion has been completely replaced in argonic acid groups during the initial extraction hours, in high temperature may lead to the separation of sodium ions and also cause de-polymerization of the alginate so in alkaline step, all factors have effect on yield, polyphenol and apparent viscosity of extracted polymer. The optimized conditions of extraction of sodium alginate from brown algae (Nizimuddinia zanardini)were as follows: temperature: 60 oC, time: 3 h (acidic step) and temperature: 60 oC, time: 3 h and concentration 3 % w/v (alkaline step).

Most of the food packaging materials are produced from nondegradable polymers which has become a serious environmental problem. Natural ingredients based on polysaccharides, offer an alternative for synthetic packagings that minimize the environmental pollution with a relatively low cost. The aim of this study was to evaluate the effect of solid lipid nanoparticles (SLN) on morphology, mechanical and barrier properties of sodium alginate film. For this purpose, the nanoparticles were added at concentrations of 0.025%, 0.5% and 0.1% into the alginate films and optical properties, tensile strength, elongation at break (%), Young’s modulus, water vapor permeability (WVP) and the nano-structured of films were evaluated. As SLN concentration increased,  elongation at break and WVP increased significantly (p<0.05), while no significant differences were found in the tensile strength and Young’s modulus (p>0.05). Films containing a high concentration of SLN (0.1%), were slightly yellowish in color and their opacity value increased significantly (p<0.05). The scaning electron micrographs showed that addition of SLN resulted in a hole-like structure in the film texture, which increased with nano-particles, concentration. Results obtained in the present work exhibited that the incorporation of SLN in alginate film was suitable for increasing the film flexibility but it had no positive effect on the film barrier properties.

Introduction. Apricot is a soft fruit that normally does not have any resistance to transportation and storage conditions. In addition, apricots are climacteric fruits, produces high levels of ethylene during ripening process and have a high respiration rate. For this reason, they are very susceptible to physiological and microbial spoilage and have a very short shelf life. Thus, it is difficult to export this product with good quality and low waste or it is very limited. Application of edible coatings could increase the storability of apricots and delay their spoilage. Edible coatings cover the surface of the fruit and function as a barrier against water vapor, respiration gasses, and microorganisms. The effect of different natural polymers as edible coatings on the quality and shelf life of different fruits has been investigated by many researchers. Chitosan has been used in the formulation of edible coatings to extend the shelf life of citrus, papaya, strawberries and grapes (Arnon et al. 2014; Ali et al. 2011; mehrzad et al. 2011; Mostofi et al. 2011). Apples coated with whey protein concentrate showed more lightness compared with non-coated ones (Perez-Gago et al. 2006). In most studies, the effects of single edible coatings on the quality of fruits have been studied. In this research the quantitative and qualitative changes during ripening and cold storage of apricots coated with different formulations of whey protein concentrate, sodium alginate and chitosan were studied.
Materials and methods "Rajabali" variety apricots were picked up at optimum maturity and damaged ones were separated. Edible coating solutions were prepared by dissolving different amounts of whey protein concentrate, sodium alginate and chitosan in to distilled water. Glycerol was used as plasticizer. The apricots were dipped in the prepared solutions with different concentrations for at least five minutes. Then they were stored for 35 days at 2°C. Some quantitative and qualitative characteristics of coated apricots, such as weight loss, acidity, color, texture, shrinkage, browning reactions, vitamin C, and microbial load were determined after 0 and 35 days of storage. The results were analyzed by response surface methodology based on central composite design with five replications at the central point.
Results & discussion. The statistical analysis of the results by central composite design (CCD) indicated that the different concentrations of whey protein did not have any significant effect on weight loss during storage. The weight loss decreased as the concentration of sodium alginate and chitosan increased. Chitosan and sodium alginate had an important role in maintaining firmness. The firmness of apricots were highest at the upper limit of sodium alginate (1%) and chitosan concentrations (2%). The b* (yellowness) and L* (lightness) values of the apricots were increased as the concentration of chitosan was increased and the concentration of sodium alginate decreased. No significant difference was observed between the a* values (redness) of apricots treated with different coatings. In addition, the acidity of the apricots was increased by increasing the concentration of chitosan and decreased by increasing the concentration of sodium alginate. Browning of the coated fruits was also increased as the concentration of chitosan was increased to 1%. Increasing the concentration of sodium alginate increased the shrinkage of the apricots at low concentrations of whey protein concentrate and decreased it at high concentrations of whey protein concentrate. It was also shown that increasing concentrations of chitosan would reduce microbial load. The optimization of the formulations with Design Expert software showed that the best formulation of edible coating for preserving apricots was 1.45% of chitosan, 1.25% of alginate, and 0 percent for Whey protein concentrate.

To investigate the effect of edible coatings in retarding of bagutte bread staling, three types of coating formulations containing Sodium alginate, carboxymethyl cellulose and xanthan as hydrocolloids and sunflower oil, glycerol, water, starch and potassium sorbate were used for coating of baguette bread and The effect of these coatings on retarding of staling after 1,2 and 3 days of storage was investigated. The obtained results revealed that after 1 day of storage the mentioned coatings presented bread with similar freshness to that of control [ fresh sample]. After 2 days of storage, sodium alginate and xanthan coated samples acted similar in retarding of staling and after 3 days of storage, all the coatings did not have any significant difference with each other and also with control sample from staling point of view.

The effects of sodium alginate coating with added thyme oil on quality of rainbow trout fillet (oncorhynchus mykiss) during chilled storage (4±10 C) were examined over a period of 20 days. A solution of sodium alginate (3%) and sodium alginate with thyme oil (sodium alginate 3% + 0.5, 1 & 1.5% thyme oil) was used for coating. The control and the coated fish fillet samples were analysed periodically (every 5 days by 20 days) for chemical (PV, TBA, FFA, TVB-N & pH) and sensory characteristics. Statistical analyses showed that pH, texture and overall acceptability in coated samples were significantly better than the uncoated samples as there was no significant difference between all coated samples. Fillets with sodium alginate enriched with 1% and 1.5% thyme essential oil had least amount of PV, FFA, TVB-N, colour and odour. The fillets with sodium alginate enriched with 1.5% thyme essential oil had least amount of TBA. The results showed that the effect of the sodium alginate coating enriched with thyme oil on the fish fillet samples was to enable the good quality characteristics to be retained for longer period of time and to extend the shelf life during the chilled storage.