Food Technology
Shokohfeh Taziki; Seyed Mohammad Ali Razavi
Abstract
Introduction Wheat starch granules are composed of amylose and amylopectin, which are responsible for the functions of starch such as swelling, gelatinization, pasting, gel formation, and retrogradation. The retrogradation changes the functional properties, it is an undesirable phenomenon in some ...
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Introduction Wheat starch granules are composed of amylose and amylopectin, which are responsible for the functions of starch such as swelling, gelatinization, pasting, gel formation, and retrogradation. The retrogradation changes the functional properties, it is an undesirable phenomenon in some starch-based foods which reduces the acceptability of food, and shortens the shelf life. Delaying or preventing of starch retrogradation is a major challenge in the food industry. Various ingredients such as carbohydrates imply an important role in improving the functional properties, decreasing amylose leaching and retarding the retrogradation of starch gels. Cress seed gum (CSG), as an emerging galactomannan, has shown the ability to improve the textural and rheological features of food systems based on its unique properties. Addition of CSG to the composite wheat-rice bread increased dough stability and improved the staleness of bread compared to guar gum. Also, the addition of CSG and xanthan gum to gluten-free bread stabilized the texture of bread during storage. Sucrose (SUC) is a common additive in food formulations which is useful as a sweetening agent and textural modification. Sugars have been able to reduce amylose leaching and accelerate or delay starch gel formation. They also delay retrogradation of starch gels during storage. Therefore, the objectives of this study were to determine the impact of different substitution levels of CSG (0, 5, 10 and 15%), SUC (0, 5 and 10%), and their blend on the functional properties (swelling strength and solubility), microstructure features, retrogradation kinetics and synthesis of native wheat starch (NWS) gel (4% w/w).Materials and Methods Cress seeds were purchased from a local medicinal market. NWS and SUC were supplied from Sigma Aldrich (Spain) and Merck (Germany) respectively. Starch suspensions (0.6 gr powder/20 ml water) substituted with CSG (0, 5, 10, and 15% w/w) and SUC (0, 5, and 10% w/w) were prepared to estimate the swelling power and solubility index. To produce starch gel, the 4% w/w suspensions of NWS-CSG-SUC were prepared by dissolving the appropriate amount of CSG powder and SUC in deionized water. Then, each suspension was poured into a stainless-steel cylindrical container and was heated to 95 oC and held at 95 oC for 3 min and then cooled to 50 oC while stirring continuously at 160 rpm with a mechanical mixer. Finally, the pastes were kept at ambient temperature (25 oC) for 1 h. To assess gel structure, imaging of the gels was performed by scanning electron microscopy (SEM). The retrogradation kinetics and syneresis of gel samples were determined after storage at 4 oC for 0, 1, 7 and 14 days.Results and Discussions The swelling power and solubility index of NWS increased with increasing the replacement level of CSG. CSG promotes adhesive interactions among the gelatinized granules. This can enhance the forces applied to them, facilitating water entering (increasing swelling), amylose solubilization and its exudation. In contrast, SUC compete with starch molecules for water in the system and thus preventing gelatinization and mobility of starch molecules reduced the swelling power. The starch-gum-sugar mixtures had a higher swelling power compared to the starch and starch-sugar samples. The mixed samples had higher solubility values than each of them individually. SEM images showed that the pore size of starch gel decreased and increased from 33.01 to 29.44 µm and to 45.37 µm with increasing the substitution levels of CSG and SUC, respectively. NWS-15% CSG-5% SUC gel had 31.34 µm pore size. After storage for 14 days at 4 oC, the CSG substitution with NWS reduced the rate of retrogradation and syneresis from 0.101 to 0.52 (s-1) and from 50% to 23%, respectively. It could be related to creating a film around the granules by the leaked amylose and the CSG in the continuous phase, so inhibiting further swelling and polymers leaking out and related to high water holding capacity of CSG. The addition of SUC reduced the rate of the process to 0.096 (s-1) but because of its low water holding capacity, the value of syneresis enhanced to 57%. In the mixed gels, more reduction of the retrogradation rate and syneresis was observed which was clearly at high CSG replacement. The retrogradation rate of the NWS-15%CSG-5%SUC was 0.057 (s-1) and its syneresis was 45%. According to the results, it can be concluded that 15% CSG and 5% SUC replacement levels can effectively improve the functional properties and reduce the rate of retrogradation and syneresis of NWS during storage.
Food Technology
Fariba Hadidi; Ali Ganjloo; Mohammad Hadi Fakoor
Abstract
Introduction The demand for non-dairy and reduced-calorie products has increased substantially for several reasons. Almond (Prunus dulcis) milk is highly appreciated by lactose-intolerant, hypertensive people and celiac patients whom are not able to consume animal's milk. Thus, the development of ...
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Introduction The demand for non-dairy and reduced-calorie products has increased substantially for several reasons. Almond (Prunus dulcis) milk is highly appreciated by lactose-intolerant, hypertensive people and celiac patients whom are not able to consume animal's milk. Thus, the development of various non-dairy products is essential. Desserts are the most common and popular product containing high amount of fat and sucrose. The consumption of sucrose is restricted for diabetic people due to its high glycemic index. Stevia as a low-calorie sweetener is one of the sucrose substitutes in food products. Sucrose substitutes must mimic the techno-functional properties of sucrose. Generally, commercially available sucrose substitutes do not possess all of the required characteristics. Therefore, using them in blend form with sucrose is suggested. Moreover, sucrose replacement especially in desserts generates a negative effect due to low firmness or higher syneresis. In this regard, hydrocolloids can be used to overcome those drawbacks. Therefore, the current study was carried out to investigate and optimize the non-dairy dessert formulation based on almond milk containing Tragacanth gum and stevia. For this purpose, the effect of Tragacanth gum and stevia as a sucrose replacer on the physicochemical properties such as hardness, viscosity, color coordinates including lightness, redness-greenness (a*), yellowness-blueness (b*), total soluble solids and syneresis was evaluated and optimized using Response Surface Methodology (RSM).Materials and Methods All of the materials used for the manufacturing of non-dairy dessert including raw almond, stevia and Tragacanth gum were purchased from a local market of Zanjan, Iran. For the production of non-dairy dessert, the almond milk warmed up to 40 ºC and then stevia as a sucrose substitutes and tragacanth gum powder as a stabilizer were added in the ranges of 25-75% and 0.4-1% w/w, respectively. Later, the temperature of the mixture increased to 72 ºC and kept for 10 min and then, the temperature decreased to 42 ºC to inoculate the starter culture (a mixture of Streptococcus thermophilus and Lactobacillus bulgaricus, 2% w/w). The fermentation process was completed at 37 °C for 24 h. Finally, the temperature of non-dairy dessert based on almond milk was decreased to 4ºC and kept at the same temperature until further analysis. The pH of the desserts was measured using a pH meter model AZ 86502 (AZ, Taiwan). Total soluble of the desserts was determined using a refractometer (ATAGO, Japan). Firmness was determined using a STM-5 texture analyzer (SANTAM Co., Iran) equipped with a 20 Kg load cell and 10 mm probe. Viscosity was measured using a programmable Viscometer (R/S-CPS+, Brookfield, USA) equipped with a cone-plate geometry at shear rate of 100 s−1. Instrumental color measurement was carried out by a handheld colorimeter (TES135-A, Taiwan) considering L*, a* and b* as color coordinates. Syneresis was measured by a centrifugation test. Fifteen semi-trained panelists (7 male and 8 female) were selected to evaluate sensory properties of the control (only contains sucrose) and optimized formulation samples for texture, color, appearance, taste, flavor, total acceptance using a 5-point Hedonic scale (1= dislike extremely and 5=like extremely). The RSM-central composite design was used to build up the experimental design and identify the conditions that yield highest firmness, viscosity, L*, and total soluble solids as well as lowest a*, b* and syneresis.Results and Discussion The results obtained revealed that the hardness, viscosity, a* and total soluble solids increased significantly (p<0.05) while the lightness, b* and syneresis decreased significantly (p<0.05) with increasing the Tragacanth gum in the formulation of non-dairy dessert based on almond milk. In addition, increasing the replacement of sucrose with stevia significantly (p<0.05) reduced the hardness, viscosity, total soluble solids, and increasing lightness and syneresis. However, increasing the percentage of sucrose replacement with stevia had no significant effect (p>0.05) on the changes of a* and b*. Optimization of non-dairy dessert formulation based on almond milk was carried out using numerical technique. The optimal formula was 1% Tragacanth gum and 45% replacement of sucrose with stevia. Under these conditions, hardness 0.08 N, viscosity 1.20 Pa.s, lightness 82.77, redness-greenness 0.95, yellowness-blueness 5.60, total soluble solids 8.29 ºBrix and syneresis 11.88% were obtained. The results of sensory evaluation showed that addition of Tragacanth gum and replacing stevia at the optimal levels improved the total acceptance score compared to the control sample.It can be concluded that in addition to the reliability of the RSM to select the optimal formulation conditions, Tragacanth gum and stevia can be used to produce a new, reduced-calorie and customer-friendly non-dairy dessert based on almond milk.
Esmail Khazaei; Mikhalil Piruzifard; Fariba Zeynali; Mohammad Alizadeh khaled abad
Abstract
Introduction: Meat and meat products are important sources of protein, fat, essential amino acids, minerals and vitamins, and other nutrients. Bologna sausage, a cooked meat product, is one of the most accepted processed meat products and is consumed and enjoyed worldwide. Among the meat products, sausage ...
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Introduction: Meat and meat products are important sources of protein, fat, essential amino acids, minerals and vitamins, and other nutrients. Bologna sausage, a cooked meat product, is one of the most accepted processed meat products and is consumed and enjoyed worldwide. Among the meat products, sausage and bologna in vacuum packages due to their variety, easy to use applications and being economical, have become commonplace. The most important problem with the production, storage, and sale of this kind of meat products is their syneresis in the vacuum packages. In addition to an unpleasant appearance, syneresis leads to accelerating microbial growth and undesirable changes in the flavor and odor of the product.The addition of functional ingredients helps to modify the overall technological and sensorial characteristics of a meat system such as water holding capacity (WHC), fat holding capacity, and texture properties and decrease the syneresis. Syneresis and purge are seen as a result of retrogradation of starch and this is very common in sliced and vacuum-packed meat products. Storage of meat products containing high-amylose starches, at low temperatures from around –1 °C to 0 °C for a prolonged time also favors retrogradation. The level of retrogradation depends on the type of starch and wheat starch demonstrating the greatest tendency towards retrogradation. Chitosan is a natural cationic polysaccharide antibacterial activity and antioxidant properties in muscle foods during storage. The aim of this study was Investigation the addition of functional ingredients such as chitosan and potato modified starch in the formulation on the amount of syneresis, pH, total microbial count and sensory evaluation in two type of products including beef ham and chicken ham were examined during storage. Then, the effect of vacuum packaging type and the amount of vacuum created in the package on the amount of syneresis were investigated. Material and methods: In this study, first various factors such as three levels of chitosan (0, 0.3 and 0.6%) and replace the wheat starch with three levels of potato modified (0, 5 and 10%) in the formulation on the amount of syneresis, pH, total microbial count and sensory evaluation in two type of products including beef ham and chicken ham were examined during storage time (1, 15 and 30 days). In this part of the study, samples with the least syneresis were selected. After that various factors of packaging such as two types of vacuum packaging(simple vacuum pack and skin pack) and the amount of vacuum(5 and 30 millibars) created in the package on the amount of syneresis were examined during storage(1, 15 and 30 days). Wheat starch, potato starch, and chitosan were purchased, respectively, from Faradane Company, KMC Company, and Sinaseven Company. The chicken meat was purchased from Fileh Amol Company. The beef was purchased from the Minerva Company of Brazil. All steps of samples’ preparation were performed in the Kalleh Amol Meat company. The chicken ham samples in this study consisted of 90% of the chicken meat and beef ham samples consisted of 90% of beef. Vacuum packaging was done using the machines which were manufactured by the German company Multivac. Syneresis was measured using the method suggested by Cesare et al. (e 2013). The initial weight of the ham slices before vacuum-packed was measured (P1); on the day of the analysis, the packaging was opened and the slices were dried with a disposable absorbent towel, then the dried ham slices were weighed again (P2). Syneresis was expressed as Syneresis= (P1- P2) ×100/P1. This study was conducted in a completely randomized design and Duncan multi-ranged test was used to determine differences between samples at 95% confidence level. Results and discussion: According to the results of analysis of variance, there was no significant difference between the syneresis of beef and chicken ham. The effect of storage time was significant on the syneresis and the syneresis rate increased with increasing storage time. Also, the results showed that adding chitosan and potato modified starch significantly (p<0.05) reduced the product's syneresis during storage. Potato starch has more water storage capacity and more amylopectin than wheat starch. For this reason, potato starch has a weaker retrogradation and less syneresis. Chitosan is a cationic polysaccharide with water-absorbing polar groups. Chitosan also was prevented from decreasing the product’s pH during storage time, that this result showed the antimicrobial effect of chitosan on acid lactic bacteria, especially in 15 and 30 days of storage. For that reason, chitosan prevents product’s pH to reach to its isoelectric pH. According to the sensory evaluation results, during the maintenance period, the sensory quality decreased significantly while chitosan had a significant positive effect on sensory parameters during storage time (P<0.05). The type of vacuum packaging and the amount of vacuum created in the package showed a significant effect on the amount of samples’ syneresis. Skin packaging showed less syneresis rates than simple vacuum packages. This result can be due to two reasons: one is the shrinkage of the product in the package, and the other is the amount of the film packing tangency on the surface of the products. So that by increasing the amount of vacuum, syneresis value increased significantly. Increasing the negative pressure inside the package caused increase the mechanical pressure by the packaging film on the product. In total, it can be concluded that with the addition of modified potato starch and chitosan to the formulation, as well as the use of lower-vacuum Skin packaging, the amount of syneresis of meat products can be significantly reduced.
Samira Shakiba; Morteza Khomeiri; Zeid Ahmadi; Soheil Amiri
Abstract
Introduction: Ispharzeh is a plant from genus Plantago whose seeds are used commercially for the production of mucilage. The plant is mainly cultivated in Iran and Middle East. Psyllium is mainly used as a dietary fiber to relieve symptoms of both constipation and mild diarrhea and occasionally as a ...
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Introduction: Ispharzeh is a plant from genus Plantago whose seeds are used commercially for the production of mucilage. The plant is mainly cultivated in Iran and Middle East. Psyllium is mainly used as a dietary fiber to relieve symptoms of both constipation and mild diarrhea and occasionally as a food thickener. Research has also shown benefits in reducing cholesterol levels. Basil seed gum is a novel hydrocolloid extracted from Ocimum basilicum L. seeds. It has shown promising stabilizing and emulsifying properties, which makes it a potential functional ingredient for the food industry. Previous works pointed out that these gums can be used successfully for food industry. However, a detailed study on Ispharzeh hydrocolloids seeds and basil gum has not yet been done. Therefore, the objective of this study was to evaluate the ability of using Ispharzeh hydrocolloids seed and basil gum as replacing with imported gums as well as to evaluate physicochemical, and sensory properties of ketchup sauce contain these gum were evaluated.
Materials and methods: Mixture design was employed to investigate the variation of ketchup properties with respect to operating parameters including xanthan, Ispharzeh seeds and basil gum in the range of 0 to 0.1 % using design expert software. Experiments were randomized in order to minimize the effects of unexplained variability in the observed responses due to extraneous factors. The treatments were selected regarding combination of xanthan, Ispharzeh seeds and basil gum in the range of 0 to 0.1 % using Design expert software. After extraction of gums, ketchup formulation was prepared with the treatments contain Ispharzeh hydrocolloids seeds and basil gum. Control sample contained ketchup formulation without gums. pH, apparent viscosity, syneresis, color and sensory properties of produced ketchup were evaluated.
Results and discussion: The impact of Ispharzeh seeds and basil gum addition on the pH of ketchup showed that all the treatments were in the standard pH range (3.67-3.74) according to the Iran national standard of ketchup. In addition, the results showed that addition of these gum were not significantly effect on pH. The regression coefficients were calculated according to the multiple regression coefficients and a polynomial regression model equation was fitted as quadratic equation. Regarding syneresis, all the treatments were stable with no syneresis except K2 (1% Ispharzeh) and K4 (1% basil gum). Addition of Ispharzeh and basil alone, were not significantly effect on synersis but when they used in combination and with xanthan, prevent syneresis significantly. The highest and the lowest viscosity were related to K4 (1% basil gum) and K10 (0.5 % xanthan+ 0.5% Ispharzeh), respectively. The regression coefficients were calculated according to the multiple regression coefficients and a polynomial regression model equation was fitted as quadratic equation. Hunter Lab colorimeter analyzing L*, a* and b* showed that K2 and K5 (1% xanthan) had the lowest and highest L* index. Variance analysis showed that quadratic model was fitted for L* value and coefficient correlation (0.9943) was satisfactory. In addition of effects of single gums, interaction of gums also had significant effect on lightness of ketchup. According to the results obtained from the sensory analysis, overall acceptability of K4 (1% basil gum) gained the highest scores. K2 (1% Ispharzeh) had the highest firmness so, led to unpleasant mouth feel in panelists. In addition, the presence of impurities in Ispharzeh seeds which not removed in centrifuge may darkening the produced ketchup hence got lower scores by panelists. Optimization evaluation by RSM evaluated the effects and interactions of the Ispharzeh hydrocolloids seeds and basil gum concentration to optimize ketchup properties. Optimized treatments were 0.42% Ispharzeh hydrocolloids seeds gum and 0.58% basil gum. Therefore, the values for stability tests are very close to the experimental values demonstrating that the model are applicable, which showed determination coefficient (R2) of 0.99. The formulation optimization showed that combination of 0.58% Ispharzeh and 0.42% basil gum as stabilizing agents in ketchup sauce, was a suitable replacer for imported commercial gums. Future studies on the Ispharzeh seeds and basil gum in other foods as well as the stabilization of these systems during the digestion process may help to understand the mechanism behind the functionality of these gums in food products.
