Food Technology
Sima Naji-Tabasi; Elham Mahdian; Akram Arianfar; Sara Naji-Tabasi
Abstract
Introduction: Fats have a special place in human nutrition and their main role is supplying energy for the body. But scientific findings approve an association between high fat intake and an increment risk of some diseases, such as atherosclerosis, heart disease, and …. Demand for low-fat foods ...
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Introduction: Fats have a special place in human nutrition and their main role is supplying energy for the body. But scientific findings approve an association between high fat intake and an increment risk of some diseases, such as atherosclerosis, heart disease, and …. Demand for low-fat foods has increased dramatically as people become more aware of fat consumption side effects. However, due to the multiple role of fats in food products, eliminating or decreasing fat lead to poor quality of products. Therefore, it is necessary to use a combination of fat substitutes to maintain the rheological, texture and sensory properties of the low fat food products. The use of emulsion gel structures are new methods for the production of low-fat product that has been studied in this investigation. The Pickering emulsion was used to produce the emulsion. In this method, instead of using surface-active agents, solid particles are used to stabilize the emulsion. The aim of this study was to prepare Pickering Emulsion from Isolated Soybean protein (ISP) and Basil Seed Gum (ISP-BSG) Complex. Finally, emulsion gel systems were applied as fat substitutes in cream. Materials and Methods: Basil seeds were purchased from Mashhad market. Isolated soy protein was purchased from Shandong Yuxin Bio-Tech Co. (China). Sodium azide was purchased from Applichem Inc. (Dramstadt, Germany). Sodium dodecyl sulphate (SDS) was obtained from Merck, Germany. Pickering (solid particles) of soy protein isolate (SPI) and SPI-basil seed gum (ISP-BSG) complex used as emulsifier for stabilization of cold emulsion. ISP-BSG particles were prepared with different mass ratios of ISP: BSG, 1: 0, 1: 1, 2: 1 and 3: 1 and named 1S: 0B, 1S: 1B, 2S: 1B and 3S: 1B, respectively. These solid particles were used as Pickering for emulsion preparation. Cold Emulsion was prepared by adding calcium chloride. The oil leakage, oil leakage after thermal treatments, microscopic structure, textural properties and viscoelastic properties of emulsion gel were studied. Then, the best structures used as a fat substitute in cream (5, 10 and 15%). Results & Discussion: Investigation of emulsion gel properties showed that coating the surface of emulsion droplets with solid nanoparticles formed a rigid shell that acted as a barrier against the deformation and transfer of materials from the interfacial surface. The use of ISP-BSG nanoparticles as picking particles caused more homogeneity and stiffness in emulsion gel structure. The rate of water loss in reduced fat cream was in the range of 1-2% by using the emulsion-gel system, which indicates the effectiveness of these systems in reducing dehydration in cream. The increasing replacement percentages led to increase water loss (p <0.05). However, emulsion type had no significant effect on water loss content (p> 0.05). According to the results, ISP-BSG nanoparticles impart high potential to stabilize emulsion with small oil droplets. Based on the results of the sensory test, it was found that the characteristics of the cream samples depended more on the replacement rate than the type of system used as an alternative. The presence of a fat replacement system maintained the desired quality in low-fat cream samples. Most of the samples scored higher than 3, which indicate the high acceptance of low-fat samples.
Shakiba Kianiani; Mohammad Javad Varidi; Mehdi Varidi
Abstract
Introduction: Meat and meat products contribute about 20% to human fat consumption. Fat is the main source of energy and the base of fat soluble vitamins. Besides, it improves cooking yield and water holding capacity, conserves taste and flavor of products and affects the emulsion stability, juiciness, ...
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Introduction: Meat and meat products contribute about 20% to human fat consumption. Fat is the main source of energy and the base of fat soluble vitamins. Besides, it improves cooking yield and water holding capacity, conserves taste and flavor of products and affects the emulsion stability, juiciness, costumer acceptability and structural and rheological properties of meat products. But Animal fat contains a relatively high amount of saturated fatty acids and cholesterol, which can increase the risk of cardiovascular disease, diabetes, cancer types and obesity. Thus, the meat industry is interested in merchandising fat-reduced meat products without neglecting the positive effects of fat on flavor and texture.
Various researches have shown that the substitution of fat on a polysaccharides base such as fibers, starch, gums, and gels have improved and modified the texture, residual moisture and freeze stability, and decreased the price of the products.
Aloe vera leaf gel contains about 99 – 99.5 % water and 1 - 0.5 % of the total solid content. On dry matter basis aloe vera gel consists of 55% polysaccharides, 17 % sugar, 16 % mineral, 7% protein, 4% lipids and 1% phenolic compounds (Lawless et al., 2014). The most important carbohydrates of aloe vera gel are the long chain polysaccharides, comprising glucose and mannose, known as the glucomannans [β (1, 4) – linked acetylated mannan]. All the solid content of aloe vera gel are surrounded by polysaccharide mucilage layer.
Literature review pointed out there have been little investigations into the functionality of aloe vera gel in the emulsion meat products. According to the importance of producing low - fat meat products from one hand as well as the nutritional values and health characteristics of aloe vera gel on the other hand, this study was designed to replace the fat with aloe vera gel in the production of low - fat German sausage.
Material and Methods: Sausage samples containing 40% of red meat (German sausage) were produced based on the conventional plants formula. animal fat and vegetable oil replaced by 0, 50 and 100% aloe vera gel in the German sausage formulation. All samples were cooked at 90°C temperature to achieve the core temperature of 70° C, followed by cooling, they were kept in the refrigerator (4°C) until the subsequent experiments. The AOAC (2000) methods were used for measuring the moisture content, the amount of fat, ash and protein. The amount of carbohydrate was calculated based on the calculation of the total weight difference from the sum of ash, protein, fat and moisture (according to the method FAO / WHO). The amount of energy was computed based on the total amount of energy from fats, proteins and carbohydrates. To measure the pH of samples by pH meter, method of choe et al (2013) was followed. The color analysis was done on the surface of sausage cuts by chromometer. The parameters of color include L* (lightness), a* (redness) and b* (yellowness) were measured. Texture parameters include hardness(N), cohesiveness, springiness (cm), gumminess (N), chewiness (N.cm), adhesiveness were determined by texture analyzer as described by Bourne (1978). The sensory attributes were evaluated by 10 trained panelists. A five-point hedonic scale rating (1= very bad, 2=bad, 3= neither bad nor good, 4= good, 5= very good) was carried out.
Results and Discussion: Physicochemical properties analysis indicated significant differences among meat products (p ≤.0.01). The addition of aloe vera gel resulted a decrease in fat percentage and amount of energy, an increase in moisture and carbohydrate, but the amount of pH, protein and ash content did not change. This study showed that reducing the fat content and replacing by aloe vera gel caused a significant difference in the amount of energy (p≤.0.01).With respect to the significant contribution of fat in the production of energy, the amount of energy was reduced as expected by reducing the fat of the formulation. The results indicated that the value of L * showed the negative and positive trends with animal fat and vegetable oil changes, respectively (p≤.0.01). b* decreased by reducing the amount of fat and oil (p≤0.01), but the value of a* always remained constant (p˃0.05). The presence of aloe vera gel in sausage caused a reduction in hardness, adhesiveness and gumminess (p<0.05), while it did not affect the amount of adhesiveness and cohesiveness of samples (p˃0.05).
The substitution of fat with aloe vera gel had a significant effect on the sensory characteristics of German sausage (p≤.0.01). By reducing fat and oil and adding aloe gel to the German sausage formulation, color acceptance score was decreased. In terms of panelists, the blank sample had the best color and the fifth sample color had the lowest score. Juiciness of the samples was increased by increasing the amount of gel. The results also showed that the fifth sample received the maximum score of juiciness. Sausages smell acceptance negatively changed by reducing the fat content and adding aloe vera gel. Third and fourth treatments got the highest texture score. Also, the third sample had the highest scores for taste and general acceptance. Chewiness analyzing showed that by increasing the amount of fat replacement the rate of this factor decreased. as well as the maximum rate of chewiness was related to the blank sample.
