In the present study, the fish protein isolate (FPI) of wastes of Siberian sturgeon (Acipenser baerii) has been substituted with fish minced (10, 20, 30, and 40%) in preparing fish nuggets. After preparing fish nuggets (88% Silver carp fillet) and initial cooking, the parameters such as approximate analysis, product yield, weight loss, pick-up, microbial growth, and sensory evaluation were investigated. The results showed that the lowest amount of moisture is related to the IP40 Group and no significant difference exists between other treatments. In comparison, the amount of protein in the control sample was the highest (18.00 ± 0.04) and it was decreased with the increase of FPI substitution (P<0.05). The highest amount of weight loss during final cooking was related to the control and IP10 treatments, and the highest product yield was associated with IP20, IP30, and IP40 treatments (P<0.05). The microbial growth results did not show any significant difference among the treatments (P>0.05). Moreover, the sensory evaluation showed the control group, which was only with fish minced, had better taste, smell, texture, etc. than the treatments containing isolated protein. The results of this research showed that the minced fish of silver carp and the FPI by-product can be used to produce fish nuggets, and although in some physical properties, the nuggets containing higher amounts of isolated protein have shown better results, according to the amount of protein and sensory evaluation, the control and the sample containing %10 FPI had better results.

Background and objectives: Tragacanth gum (GT) is one of the natural secreted hydrocolloids which has many applications in food and pharmaceutical industries. Unfortunately, there is limited scientific information about the electrostatic interactions of tragacanth gum with proteins, especially the proteins unfolded by physical approaches. In this regard, the main objective of this study was to investigate the effect of thermal processing on the whey protein isolate (WPI) properties and its complexation with tragacanth gum. Materials and methods: The influence of heating time (0, 5, 10, 15, 20, 25, 30 and 35 min at 80 C) on the turbidity of WPI, alone and mixed with GT (r = 0. 1, pH 4. 0 and Cp 0. 1 w/w) was surveyed. Then, the flow behaviour and viscosity of GT-WPI mixture at a shear rate of 0-100 S-1 (pH 4. 0) was compared with the individual solutions of gum and protein. Since the maximum turbidity was observed in the range of 15-35° C, the impact of heating time at three levels (15, 25 and 35 min) and biopolymer mixing ratio at six levels (2: 1, 1: 1, 1: 2, 1: 5, 1: 10 and 1: 20) on the protein and carbohydrate compositions of precipitate and supernatant was investigated by Lowry and phenol-sulphuric acid methods, respectively. Results: Turbidity of protein solutions significantly changed with rising the heating time such that the maximum turbidity achieved after 25 min thermal processing. While these solutions were unstable due to protein-protein interaction and formation of protein aggregates, GT addition led to significant changes in the stability of protein solutions as a result of protein-polysaccharide interactions. Similar to protein solutions, the maximum turbidity of the complexes was achieved after 25min thermal processing. The rheological measurements showed that the mixture solution had pseudoplastic behavior with a large hysteresis loop as well as the higher viscosity rather than the blank solutions, indicating the formation of electrostatic interactions between protein and polysaccharide. By determining protein and polysaccharide content in the supernatant and precipitate phases, the least ratio of Pr: PS was observed for the 25-min heated WPI. Furthermore, the ratio of Pr: PS in the precipitate was increased significantly as Pr: PSratio was increased in the mixture. Conclusion: Addition of tragacanth gum to the whey protein isolate led to a significant stability in the solution. Due to unfolding of WPI, using thermal processing on the whey protein isloate solution resulted in a meaningful increase in the turbidity of protein solution and the efficiency of GT-WPI complex formation.

Impact of bambara groundnut protein isolate (BGPI) on autolysis and gel properties of surimi from lizard fish was investigated. As the levels of BGPI increased (0-3%), breaking force, deformation and retention/ stability of myosin heavy chain (MHC) of modori gel markedly increased (P<0.05). Nevertheless, only 0.25% BGPI increased above parameters in kamaboko gel. A decreasing trend in whiteness and expressible moisture content of kamaboko gel was observed when the BGPI levels increased. Because of suitability of 0.25% BGPI in kamaboko gel, this level was selected for determination of microstructure and sensory analysis. Microstructure of kamaboko gel added with 0.25 %BGPI had a more compact structure than that without BGPI addition. Regarding sensorial properties, elasticity, texture and general acceptance of kamaboko gel added with 0.25% BGPI was significantly higher than control (P<0.05). Therefore, BGPI at an appropriate level could be a protease inhibitor to improve gel properties of kamaboko.

Functional properties of total protein isolate (TPI) were investigated. The moisture content and ash content of the TPI was found to be 9.16% and 3.92% respectively. The nitrogen solubility of the protein isolate was found to be maximum at pH 7. The foaming capacity, emulsifying activity and emulsifying stability were greatly affected by pH levels.Viscosity of the TPI solution also changes with pH and increases increase in concentration.Gelation properties of the protein isolate solution were investigated and the lowest gelation concentration was found to be 10%. Water holding capacity of the protein isolate was 3.60 g water/g protein and the oil holding capacity was 2.02 g oil/g protein.

Persian gum is an anionic polysaccharide, exudes from mountain almond tree. Unfortunately, there is no information about its interaction with unfolded proteins. The objectives of the current study are investigation of heating time on the properties of WPI and the complexes thereof. In this regard, first the effect of thermal processing (at 80°C, for 0-35 min) on the turbidity of whey protein isolate was surveyed at pH 4.0. The electrostatic interaction between treated WPI and Persian gum was also surveyed as a function of heating time and mixing ratios (2: 1, 1: 1, 1: 2, 1: 5, 1: 10 and 1: 20). Results indicated the significant increasing in the turbidity of treated WPI solutions (mainly after 25 min) with a high inconsistency leading to the precipitation due to the protein-protein interactions at low pH and formation of large aggregates. Addition of Persian gum (PG) caused the formation of WPI-PG complexes and meaningful increasing in the stability of the mixture solutions. Furthermore, the rheological measurements (0-100 S-1) showed that the mixture solution has pseudo plastic behavior with a large hysteresis loop and higher viscosity rather than the blank solutions, indicating the formation of protein polysaccharide complexes. By calculation of protein and polysaccharide in the supernatant and precipitation phases, the most biopolymer concentration in the precipitation phase was demonstrated for the 35-min-treated WPI. On the other hand, the amount of polysaccharide was increased in the precipitation as WPI: PG mixing ratio decreased.

This study investigated the composition and functional properties of isolated fish protein from Lanternfish (Benthosema pterotum). The proteins were isolated by using pH shift method. Basic pHs (10 and 12) were used to produce fish protein isolate. Fat contents of samples revealed that alkaline had a significant effect on reduction of fat in fish protein isolate. The lipid content decreased significantly by increasing the pH. Furthermore, the results showed that the functional properties including water holding capacity, oil holding capacity, emulsifying capacity, foaming and solubility were improved with increasing the pH and the fish protein produced at pH 12 had higher functional properties than the protein isolated at pH 10. Investigation and comparison of the color characteristics (L, a and b) attributed to the samples demonstrated that fish protein isolated at pH 12 was lighter (higher L) than that isolated at pH 10. In addition, redness (a) and yellowness (b) of protein isolates declined with increasing the pH. As a result, fish protein isolate from Lantrnfish produced using alkaline pH showed appropriate functional properties and alkaline led to improvement of the functionality and color characteristics of the protein isolate.

Because of the sensitivity of probiotic bacteria to storage conditions as well as to the specific digestive system, protection of the bacteria against these conditions seems necessary. The aim of this study was to investigate the effect of encapsulation by soy protein isolate, whey protein isolate and inulin on the viability of Lactobacillus reuteri in gastrointestinal condition and during storage. As can be seen from the results, the soy protein isolate-coated samples had higher moisture content than the whey protein-coated samples, and the addition of inulin reduced the moisture content of the samples. The results of water activity were also similar with the results of moisture content. The microscopic structure results show that the samples containing whey protein are more uniform. Survival results in the simulated gastric system indicate that the number of bacteria in the simulated gastric system decreases over time and the largest decrease occurred in the control sample. Between the microencapsulated samples, whey proteinencapsulated had the highest viability (86. 3 %). Also, survival results in the simulated intestinal system show that the number of bacteria in the simulated intestinal system decreases during storage and the largest decrease occurred in the control sample, (un-coated sample). Among the encapsulated samples, the sample containing whey protein and inulin had the highest viability (88. 75 %). As can be seen from the viability of the probiotic bacteria during the shelf life, the bacterial count decreased over time and the highest decrease occurred in the soybean protein isolate sample. Among the samples, the whey protein-coated sample with inulin had the highest viability.

In this research, nanoparticles of milk protein isolate (MPI) were produced by electrospraying method. In order to optimize the electrospraying conditions of MPI nanoparticles, the concentration of MPI solution (%wt.), the process voltage (kV), the moving distance of the particles between the tip of the needle and the collector (cm) and the pump flow rate (mL/h) in the form of a composite plot central (CCD) were investigated and modeled and analyzed by the response surface method (RSM). The results showed that the concentration of MPI solution had the greatest effect and the distance between the tip of the needle and the accumulator had the least effect on the diameter of nanoparticles. According to the results, by optimizing the concentration of MPI solution (2.5%wt.), pump flow rate (0.2 mL/h), the distance between the tip of the needle and the collector (15 cm) and voltage (17.5 kV), uniform MPI nanoparticles can be obtained. The images from the scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed the success of the electrospray method in producing spherical nanoparticles with an average diameter of 329.3 nm and maximum uniformity in particle size distribution. Also, Fourier transform infrared spectroscopic (FTIR) analysis revealed the chemical structure of nanoparticles.

Macaroni and pasta products are one of the favorite dishes in the world. In Iran, it improves its position in family food programs. In recent years, using additives and different components to improve quality and nutritional properties of this product have been used.Soy protein isolate (SPI) added to semolina to improve quality and quantity of protein and amino acid profile of final product such as macaroni. The aim of this study was the effects of adding different level of SPI (1, 2, 4 and 6% on semolina basis) on the properties of macaroni have been investigatedResult showed that by increasing the amount of SPI, water absorption of dough was decreased. Also by increasing the amount of SPI, the value of protein and ash contents were increased. Although the amount of soluble solid, cooking quality index, moisture content and pH value had fluctuation.Sensory evaluation of products in terms of color, taste, chew ability and stickiness were determined by 5 trained panelists. These two samples and control sample were evaluated by 30 untrained panelists with using preference test. The result showed that the sample contained 2% SPI was recognized the best regarding chemical, rhological and cooking quality index. In order to determine amino acid profile, the sample containing 2% SPI and the control sample were analyzed by HPLC. The result indicated that the amounts of amino acids were increased but methionine did not. Lysin and Hysidin showed maximum and minimum increase respectively 32.1% and 2.2%.

The purpose of this study was to produce the low fat yogurt using soy protein isolate. The soy protein isolate in concentrations of 0.5, 1.0 and 1.5 was used in low-fat yogurt formulation and the physicochemical properties (pH, acidity, non fat dry matter, syneresis, viscosity) and microbial (growth of mold and yeast) and sensory properties (color, firmness, taste, sourness, spiciness, oldness and moldy and overall appearance) were evaluated on 1, 7, 14 and 21 days of storage. The results showed that with increase in soy protein isolate concentration, acidity, non fat dry matter and viscosity were significantly increased and the yogurt syneresis was significantly decreased, while it had no significant effect on pH (p > 0.05). The most desirable sensory properties were observed in the first days in the control and samples containing 0.5 and 1.0% soy protein isolate (p < 0.05). The results showed that the use of soy protein isolate due to its nutritious compounds can be considered as an offer in the industrial production of functional low fat yogurt.