Comprehensive structural and functional characterization of a new protein-polysaccharide conjugate between grass pea protein (Lathyrus sativus) and xanthan gum produced by wet heating.

The purpose of this work was to use a controlled wet-heating process to promote Maillard reaction (MR) between grass pea protein (GPPI) and xanthan gum (XG), and then analyse structural, functional and antioxidant properties of the conjugate (GPPI-XGCs). During heating, the degree of glycation of all conjugated samples was raised (up to 37.43 %) and, after heating for 24 h, the lightness of the samples decreased by 24.75 %. Circular dichroism showed changes in secondary structure with lower content of α-helix and random coil in conjugates. XRD patterns showed that MR destroyed the crystalline structure of the protein. In addition, Lys and Arg content of the produced conjugates decreased by 16.94 % and 6.17 %, respectively. Functional properties including foaming capacity and stability were increased by 45.17 % and 37.17 %, and solubility reached 98.88 %, due to the protein unfolding driven by MR. GPPI-XGCs showed significantly higher antioxidant activities with maximum ABTS-RS value of 49.57 %. This study revealed how MR can improve GPPI's properties, which can aid the food industry in producing a wide range of plant-based foods. Especially, among other characteristics, the foaming properties were significantly improved and the final product can be introduced as a promising foaming agent to be used in food formulation.

Enhancing Rheological and Textural Properties of Gelatin-Based Composite Gels through Incorporation of Sesame Seed Oleosome-Protein Fillers.

In this study, the protein and oleosomes of sesame seeds were extracted individually and used to prepare a gel composed of gelatin, protein, and oleosomes. Mixtures of gelatin and sesame seeds protein were prepared, and oleosomes with different percentages (0, 10, 20 and 30% of their weight) were used. Different amounts of oleosomes in the composite gel samples were examined for their morphological, rheological, and textural properties. The results of the viscoelastic properties of different composite gel samples indicated that a higher percentage of oleosomes would increase the storage modulus (G'), loss modulus (G″), and complex viscosity (η*). The storage modulus of all gel samples was greater than the loss modulus, suggesting a solid behavior. So, in the sample with 30% oleosome, the storage modulus and the loss modulus reached 143,440 Pascals and 44,530 Pascals. The hardness and breaking force in samples containing 30% oleosome reached 1.29 ± 0.02 and 0.17 ± 0.02, respectively. In general, it can be said that composite gels based on gelatin-sesame seed protein modified with oleosome can be used as a part of food components in various dairy products, gelatin desserts, lean meat products and the production of useful products.

Mixed fermentation and electrospray drying for the development of a novel stabilized wheat germ powder containing highly viable probiotic cultures.

Nondairy fermented probiotic powder was developed based on stabilized wheat germ through mixed fermentation (Lactobacillus acidophilus and Lactobacillus plantarum) and electrospraying process. In the first step, the effect of mixed fermentation on lipase and lipoxygenase activity of wheat germ was investigated. The results showed a significant reduction in the activity of both enzymes (82.72% for lipase and 72% for lipoxygenase), therefore, mixed fermentation effectively stabilizes the wheat germ. In the next step, after the preparation of the solutions for drying process and investigating the physical properties (surface tension, electrical conductivity, and viscosity) of the solutions, the electrosprayability of the samples was evaluated at different conditions and revealed that 18 kV applying voltage, 0.3 flow rate, and 12 cm distance between tip to collector was the best for electrospraying the 20% solution of fermented wheat germ with morphologically most semi-uniform particles. Finally, the viability of the probiotics after drying process and during the storage at 25°C was examined. The number of initial cells counted as 14.48 ± 0.2 log cfu/g and the viability studies showed 0.55 log cfu/g decrease in the number of viable bacteria from initial count as a result of the electrospraying process. Furthermore, 7.86 ± 0.03 log cfu/g in freeze-dried and 9.05 ± 0.45 log cfu/g in electrosprayed samples survived after 70 days of storage.

The effect of periodate oxidation of basil seed gum and its addition on protein binding.

This study attempted to determine the best point of basil seed oxidation by applying response surface methodology (RSM) with 3 factors of temperature (35-45 °C), pH (3-7) as well as time (3-7 h), at 3 levels. The produced dialdehyde basil seed gum (DBSG) was collected and its physicochemical properties were determined. Fitting of quadratic, linear polynomial equations was subsequently done by considering the insignificant lack of fit, as well as highly considerable R2, in order to probe the probable relationship existing between these considered variables as well as the obtained responses. So the considered optimal related test conditions, which included pH = 3, T = 45 °C as well as Time = 3 h, were specified to produce the highest percentage of aldehyde (DBSG32), optimal (DBSG34) and the (DBSG74) samples with the highest viscosity. The results obtained by FTIR and aldehyde content determination provided the indication that dialdehyde groups were formed in a way that was in equilibrium with the considered the hemiacetal form which was dominant. Furthermore, AFM investigation related to the considered DBSG34 sample displayed over-oxidation as well as depolymerization; this might be due to the enhanced hydrophobic qualities, as well as the decreased viscosity. While the DBSG34 sample had the most dialdehyde factor group with a particular tendency for the combination having the proteins' amino group, DBSG32 and DBSG74 samples could be desirable for industrial uses owing to no overoxidation.

Nitrogen and phosphate removal from dairy processing side-streams by monocultures or consortium of microalgae.

Acid-casein production generates waste streams that are rich in nitrogen (in the form of protein and nitrate) and phosphate. This makes this type of waste very difficult to treat using conventional techniques resulting in a high amount of operating cost and costly investment. In this research, the application of single culture or consortium of microalgae for uptake of nitrogen and phosphate in the wastewater of an acid-casein factory was investigated. The waste was a 1:1 mixture of nanofiltered whey permeate and dairy processing wastewater. Monocultures of Chlorella vulgaris, Tetradesmus obloquus, Nonnochlropsis ocenica and a consortium of the three microalgae were analyzed. The results showed that the consortium exhibited more efficient nitrogen and phosphate removal compared to the individual species. The consortium was able to rapidly hydrolyse exogenous protein present in the waste medium, removing 88% of protein and breaking down complex protein molecules into simpler compounds (such as nitrate) for assimilation into the biomass. In the first fourteen days of cultivation, the rate of nitrate assimilation by the consortium biomass was lower than that of nitrate formation from protein degradation, leading to a net increase in nitrate concentration in the medium. As protein source was depleted and biomass concentration increased, however, the rate of nitrate assimilation began to exceed that of nitrate formation allowing for net removal of nitrate. The microalgae consortium was shown to successfully bioremediate all nitrates by day 21. It was indicated that Chlorella and Nannochloropsis species were responsible for nitrogen removal in monocultures. Phosphate, on the other hand, was efficiently removed by Tetradesmus. The results indicated that a consortium cultivation of three species of microalgae led to effective elimination of both nitrogen and phosphate. Combined flow-cytometry and microscopy analyses revealed that Chlorella overtook Tetradesmus and Nannochloropsis to emerge as the dominant population in the consortium by the end of the cultivation cycle. It can be concluded that the application of microalgae consortium for simultaneous recovery of nitrogen and phosphate is a promising approach for treating acid-casein wastewater.

Production and Optimization of Conjugated Linoleic and Eicosapentaenoic Acids by Bifidobacterium lactis in Cold-Pressed Soybean Cake.

Background and Purpose: In regard to the biosynthesis of conjugated linoleic acid (CLA) and eicosapentaenoic acid (EPA) by some bacteria, the objective of this study was to evaluate the efficiency of solid-state fermentation based on soybean pressed cake (SPC) to produce CLA and EPA by Bifidobacterium lactis. The objective of this study was to evaluate the efficiency of solid-state fermentation based on SPC to produce CLA and EPA by B. lactis. Methods: Process conditions including humidity, inoculation level, and temperature parameters were optimized by adopting the response surface methodology (RSM) method (response surface method) and the design expert software. Accordingly, a homogeneous SPC paste substrate at 60, 70, and 80% humidity was prepared with different inoculation levels at 30, 37, and 44°C to assess the strain behavior. The introduced SPC consisted of 60% humidity, 2% inoculation level at 37°C, and 60% humidity, and 4% inoculation level at 30 and 44°C; it also included 6% inoculation level at 37°C, 70% humidity at 2% inoculation level, at 30 and 44°C, and 4% inoculation level at 37°C. Also, SPC with 80% humidity at 2% and 4% inoculation levels, and at 30 and 44°C was obtained. To confirm the accuracy of the conditions, an experiment was conducted according to the defined requirements. Results: The results were compared with the predicted data, which showed a significant difference. Under optimized conditions, with an inoculation level of 4% on the SPC medium with 70% humidity and at 37°C, B. lactis strains could yield 9cis-, 11 trans-linoleic and eicosapentaenoic at 0.18 and 0.39% of the total fatty acids. Conclusion: So, the potential benefits of using SPC as an inexpensive substrate for the commercial production of CLA and EPA should be noted.

Modifying the Stability and Surface Characteristic of Anthocyanin Compounds Incorporated in the Nanoliposome by Chitosan Biopolymer.

In this study, a novel approach was investigated to improve the stability of anthocyanin compounds (AC) by encapsulating them in nanoliposomes resulting from rapeseed lecithin alongside chitosan coating. The results indicate that the particle size, electrophoretic mobility, encapsulation efficiency, and membrane fluidity of nanoliposomes containing anthocyanin compounds were 132.41 nm, -3.26 µm·cm/V·S, 42.57%, and 3.41, respectively, which changed into 188.95 nm, +4.80 µm·cm/V·S, 61.15%, and 2.39 after coating with chitosan, respectively. The results also suggest improved physical and chemical stability of nanoliposomes after coating with chitosan. TEM images demonstrate the produced particles were spherical and had a nanoscale, where the existence of a chitosan layer around the nanoparticles was visible. Shear rheological tests illustrate that the flow behavior of nanoliposomes was altered from Newtonian to shear thinning following chitosan incorporation. Further, chitosan diminished the surface area of the hysteresis loop (thixotropic behavior). The oscillatory rheological tests also show the presence of chitosan led to the improved mechanical stability of nanoliposomes. The results of the present study demonstrate that chitosan coating remarkably improved encapsulation efficiency, as well as the physical and mechanical stability of nanoliposomes. Thus, coating AC-nanoliposomes with chitosan is a promising approach for effective loading of AC and enhancing their stability to apply in the pharmaceutic and food industries.

Stabilization activity of a new protein-carbohydrate complex in sesame paste: rheology, microstructure, and particle size analysis.

BACKGROUND: Sesame protein concentrate is a by-product of sesame processing with great nutritional and functional value. In the present study, sesame protein concentrate and a conjugated form of the protein with maltodextrin were applied to improve stability and texture of sesame paste. The rheological properties of samples were studied using dynamic measurement, controlled rate and controlled stress rheological analysis, and creep analysis to investigate the sesame paste structure and to illustrate the mechanism of their stability against oil separation. RESULTS: Samples containing the conjugate showed good stability, low average droplet size and uniform microstructure. Creep analyses showed as the conjugate was added to sesame paste, µ0 and µ1 values (corresponding dashpot viscosities) were higher than that of G0 and G1 (shear moduli of Maxwell and Kelvin-Voigt springs). Dynamic shear test exhibited increased storage modulus (G') and loss modulus (G″) by the increase in frequency and elastic structure of sesame paste converted to viscose behavior with the contribution of conjugate. CONCLUSION: Particle interaction in sesame protein concentrate (SPC)-maltodextrin conjugate (SMC), may be overcome by steric repulsion force. Furthermore, impression of a weak network structure can be observed. These phenomenon could resolve the phase separation problem of traditional sesame paste. © 2022 Society of Chemical Industry.

Monitoring of Aflatoxin M1 in milk using a novel electrochemicalaptasensorbased on reduced graphene oxide and gold nanoparticles.

Accurate and rapid detection of Aflatoxins as one of the most hazardous compounds in foodstuffs is very important. In this study, a label-free electrochemical aptasensor was developed to identify aflatoxin M1 using a reduced graphene oxide (rGO) and gold nanoparticles (AuNPs)-based pencil graphite electrode (PGE). The morphological characteristics of the electrode surface were investigated using SEM and rGO functional groups were confirmed by FTIR. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were used to characterize various stages of electrode modification. In order to optimize the impedimetric response of the aptasensor, aptamer immobilization time, aptamer concentration, and binding aflatoxin M1 with aptamer time were optimized. Under optimal conditions, the linear concentration range of 0.5-800 ng/L and limit of detection (LOD) of 0.3 ng/L were obtained for aflatoxin M1 by measuring the resistance charge transfer data. Finally, the fabricated aptasensor was successfully used to measure AFM1 compared to HPLC method.

The chemical composition and heavy metal content of sesame oil produced by different methods: A risk assessment study.

The oil was extracted from sesame seed with two extraction methods. Traditional (Ardeh oil) and industrial method (cold pressing method: virgin and refined sesame oil) oil extraction was studied to compare the quality and heavy metal content of extracted oils. The chemical properties (fatty acid composition, peroxide, anisidine, acid values, and TOTOX) and heavy metal contents were investigated. The Hazard Quotient (HQ) and Hazard Index (HI) of heavy metal intakes were calculated. The results demonstrated that the predominant fatty acid in oil samples was oleic, linoleic, palmitic, and stearic acids. It was indicated the peroxide, anisidine, acid values, and TOTOX of oil samples were as the order of Ardeh oil > virgin sesame oil > refined sesame oil. The reduction pattern of Pb > Zn >Cu > Cd >As was reported in sesame seed. Although the oil refining had been greatly reduced the Pb of oil sample, but it had yet been much higher than the permissible levels set by Codex Alimentarius. The HQ and HI of all heavy metals were less than one, but they were higher in Ardeh oil compared to others. It is necessary to monitor the presence of heavy metal contaminants and the quality of imported sesame seeds prior to oil preparation.

Utilization of chickpea protein isolate and Persian gum for microencapsulation of licorice root extract towards its incorporation into functional foods.

This study aimed at the fabrication of licorice extract (LE)-loaded microparticles by complex coacervation, using chickpea protein isolate (CPI) and soluble fraction of Persian gum (SFPG). The LE-loaded microparticles with the highest encapsulation efficiency (97.87%) and loading capacity (11.35%) were obtained at pH 3 and CPI: SFPG ratio, core: coating ratio, and polymer concentration of 2, 1.5, and 2, respectively. The LE-loaded microparticles (2-15 µm) possessed heterogeneous microstructure, and the Fourier-transform infrared spectroscopy data confirmed the pronounced effect of electrostatic interactions and hydrogen bonding. The thermostability, amorphous structure, and color of the LE-loaded microparticles were significantly enhanced, compared to free LE. The sensory evaluation of the model beverages containing LE-loaded microparticles revealed that the microencapsulation was able to mask the bitter aftertaste and color of the extract. Thus, the results of this research confirm the potential of CPI-SFPG complex coacervates for the efficient delivery of glycyrrhizin via incorporation into functional food products.

Encapsulation of Berberis vulgaris Anthocyanins into Nanoliposome Composed of Rapeseed Lecithin: A Comprehensive Study on Physicochemical Characteristics and Biocompatibility.

In the present study, nanoliposomes composed of rapeseed lecithin were used for the encapsulation of anthocyanin compounds (AC). The nanoliposomes were prepared using hydration and ultrasound combined method, and the effect of AC concentration (4.5, 6.75, 9% w/w) on the characteristics of nanoliposomes including particle size, polydispersity index (PDI), zeta potential, and the encapsulation efficiency (EE) of nanoliposomes with and without AC were studied. The results suggested the fabricated nanoliposomes had a size range of 141-196 nm, negative zeta potential and narrow particle size distribution. Further, the samples containing 9% extract had the maximum EE (43%). The results showed elevation of AC concentration resulted in increased particle size, PDI, EE, and surface charge of nanoparticles. The presence of AC extract led to diminished membrane fluidity through the hydrophobic interactions with the hydrocarbon chain of fatty acids. TEM images suggested that the nanoliposomes were nearly spherical and the AC caused their improved sphericity. Further, in vitro biocompatibility tests for human mesenchymal (MSC) and fibroblast (FBL) cells indicated nanoparticles were not toxic. Specifically, the best formulations with the maximum compatibility and bioavailability for MSC and FBL cells were AC-loaded nanoliposomes with concentrations of 0.5 mL/mg and 10.3 mL/µg and, respectively.

Efficiency of fluorescence in situ hybridization (FISH) method for the rapid detection of Salmonella in minced lamb meat: Method analysis and optimization.

Salmonella contamination has been always regarded as one of the main issues in different food products especially fresh meat, while its detection time is normally beyond the shelf life of fresh products. In this paper, a 16S RNA based FISH method was developed for the detection of Salmonella in minced lamb meat. The parameters affecting the method including temperature, probe, salt and formamide concentrations, were optimized for FISH efficiency. Then the method was used to detect Salmonella in culture media and in minced lamb samples at the presence or absence of other pathogenic bacteria. The optimized condition included the probe concentration of 50 micromolar, salt concentration of 0.464 M, formamide concentration of 35%, and temperature of 60 °C. The optimized method could successfully reveal the presence of Salmonella in samples with a complex environment. The study showed that FISH could be a reliable method for the rapid and accurate detection of Salmonella in minced lamb, provided that the method parameters are at their optimal values. This method can be suggested as a convenient, rapid, and reliable method for safety assurance of fresh meat.

Characterization and identification of sediment forming agents in barberry juice.

Cloud and sediment formation is a major problem in juices and drinks. Barberry juice, as a functional and healthy product, is faced with the sedimentation problem, as an emerging issue. The present study was carried out to identify the sediment forming agents in barberry juice concentrate. The sediment was characterized by a range of different analytical techniques including FTIR, UV spectrophotometry, HPLC and LC-MS analysis. The findings of this research revealed that sugar derived organic acids, which were present in high amounts in barberry juice, were mainly responsible for sedimentation of barberry juice concentrate during cold storage. It was reported that such sugar derived acids with active carboxylic groups could cause instability in products rich in these compounds. The isolated sediment could re-crystalize at different juice concentrations with different shapes and sizes as affected by nucleation and crystal growth rates.

A new functional protein­polysaccharide conjugate based on protein concentrate from sesame processing by-products: Functional and physico-chemical properties.

Ardeh or Tahin residue, a by-product from oil extraction and processing of dehulled, roasted and milled sesame, contains a high amount of proteins. In this research, the protein was extracted as sesame protein concentrate (SPC) and its physicochemical and functional properties were investigated. In order to improve the functional properties of sesame protein concentrate, SPC-maltodextrin conjugates (SMC) were prepared. The conjugated substance was analyzed by means of different instrumental techniques. The covalent attachment of maltodextrin to SPC was confirmed by Fourier transform-infrared analysis and SDS gel electrophoresis. The protein exhibited a poor solubility that was affected by pH, while conjugation significantly enhanced the solubility providing a soluble substance in a wide range of pH. The emulsifying capability of SMC was higher than that of SPC and emulsions with smaller droplet sizes were obtained. Circular dichroism spectroscopy showed that the secondary structures were changed significantly by conjugation. Structural flexibility of the molecules was increased, improving the functional characteristics of the protein. The results showed that Ardeh residue could be a potential alternative renewable plant protein source to be used as a food ingredient for the enhancement of food nutritional value and quality especially after conjugation with maltodextrin.

Study on physico-mechanical and gamma-ray shielding characteristics of new ternary nanocomposites.

In this study, a series of "Epoxy-Clay-PbO" nanocomposites under the name of ECPNCs were prepared by the molding method, and their physico-mechanical properties were investigated by different techniques. Focus of the work, was on the shielding ability of the ECPNCs for the gamma rays, emitted from Ir-192, Cs-137 and Co-60 with a wide range of energy. Scanning electron microscopy, and X-ray diffractometry demonstrated that clay platelets were fully exfoliated, and the PbO particles were homogenously distributed in the polymeric matrix. Thermo-gravimetric analysis and standard tensile tests revealed that PbO content has an "increasing/decreasing" effect on "thermal stability/mechanical strength" of the nanocomposites. Gamma shielding experiments showed that efficacy of ECPNCs containing 30 wt% PbO was 47% better than that of concrete. Experimental attenuation data were confirmed by theoretical calculations, so that the maximum difference between them was 14.1%. Furthermore, a correlation was developed between PbO content of the ECPNCs and their mass attenuation coefficient for all gamma sources.

Thermodynamic and physiochemical insights into chickpea protein-Persian gum interactions and environmental effects.

In the present work, the interactions between chickpea protein isolate (10 g·L-1) and soluble fraction of Persian gum with various concentrations (from 0 to 14 g·L-1) at different pH (3, 5, and 7) was characterized using turbidity, zeta-potential, differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and isothermal titration calorimetry (ITC). The turbidity was significantly measured bigger at pH 3 than others followed by pH 7 and the minimum value of turbidity was obtained for pH 5. Regardless of the pH, the maximum turbidity was measured at the SFPG/CPI ratio 1. Zeta-potential results showed a good perspective about making coacervates at pH 3 and soluble complexes at pH 7 and even pH 5. DSC results depicted that denaturation temperature of CPI was bigger with the presence of SFPG than CPI alone. Evaluation of the shifting and changing the intensity of peaks obtained by FTIR proved making the interactions between functional groups of biopolymers. The ITC results showed the electrostatic and hydrophobic interactions were responsible for making complexes and coacervates at pH 3 in the event that the hydrophobic interactions caused to binding the biopolymers together.

Change in the color of heat-treated, vacuum-packed broccoli stems and florets during storage: effects of process conditions and modeling by an artificial neural network.

BACKGROUND: Vacuum-packed broccoli stems and florets were subjected to heat treatment (60-99 °C) for various time intervals. The activity of peroxidase was measured after processing. Thermally processed samples were then stored at 4 °C for 35 days, and the color of the samples was measured every 7 days. Effects of parameters (heating temperature and duration, storage time) on the color of broccoli were modeled and simulated by an artificial neural network (ANN). RESULTS: Simulations confirmed that stems were predicted to be more prone to changes than florets. More color loss was observed with longer processing or storage combinations. The simulations also confirmed that higher temperatures during heat processing could retard color changes during storage. For stems treated at 80 °C for short durations, color loss was more predominant than both 65 and 99 °C, probably due to the incomplete inactivation of enzymes besides more tissue damage, with increased enzyme access to the substrate. CONCLUSION: The greenness of both stems and florets during storage can be better preserved at higher temperatures (99 °C) and short times. The simulation results revealed that the ANN method could be used as an effective tool for predicting and analyzing the color values of heat-treated broccoli. © 2018 Society of Chemical Industry.

Development of chitosan based extended-release antioxidant films by control of fabrication variables.

In this study, mechanical, optical and permeability to water vapor of chitosan containing α-tocopherol film as the function of preparation conditions including concentration of emulsifier and speed of homogenization have investigated. In addition, the effect of above mentioned variables and presence of ethanol as co-surfactant on the release rate of α-tocopherol from chitosan film to fatty food simulant (ethanol 95%) were investigated. Fourier transform infrared spectroscopy and differential scanning calorimetry were employed to analyze the structural and thermal properties of the films. Results showed that the incorporation of α-tocopherol and preparation conditions affected the physical and mechanical properties of the chitosan films. Obtained results indicated that increasing the concentration of Tween 80 increased the release rate of α-tocopherol in the most studied films. Increasing the stirring speed of homogenization and the presence of ethanol considerably decreased the release rate of α-tocopherol at the most film samples. The lowest amount of released antioxidant was 8.6-10% of total incorporated α-tocopherol at the first stages and is obtained when ethanol used during preparation of film forming solution. Our results indicated that the release rate of α-tocopherol could be controlled by changing the stirring speed of homogenization and especially ethanol presence, considerably.