Properties of OSA-esterified insoluble fraction of Persian gum and its application in dairy cream.

BACKGROUND: In the present study, the insoluble fraction of Persian gum (IFPG) was modified with octenyl succinic anhydride (OSA) and its various properties were assessed. In addition, the effect of OSA-IFPG on the rheological and textural properties of dairy cream was investigated. RESULTS: Suitable conditions for achieving a degree of substitution (DS) of 0.023 were found at pH 9, IFPG concentration 4 wt%, OSA concentration 10 wt% and a temperature of 40 °C, within 120 min. The carbonyl group attachment in OSA-IFPG was also confirmed via Fourier transform infrared and H-nuclear magnetic resonance spectroscopy (1 H-NMR). While the X-ray diffraction test indicated no significant changes in the structure of the IFPG after modification with OSA, esterification increased the negative charge density, decreased thermal decomposition temperature and increased the emulsifying capacity to 100%, which was obtained for the first time. The use of OSA-modified IFPG in creams augmented the complex viscosity, loss and storage modulus, while also demonstrating the creation of a pseudo-gel network. The hardness and adhesiveness of the texture increased, which can be explained by the formation of a compact structure and reduced particle size. CONCLUSION: Overall, OSA-IFPG with hydrophilic and hydrophobic sections may function as an emulsifier and be recommended as a safe source of hydrocolloids for emulsion stability. It can also provide a positive physical structure when added to dairy cream, even if the fat concentration is lower than usual. © 2023 Society of Chemical Industry.

Preparation of octenyl succinylated kappa-carrageenan; reaction optimization, characterization, and application in low-fat vegan mayonnaise.

Kappa-carrageenan (KC) esterification reaction with octenyl succinic anhydride was optimized using response surface methodology, leading to the production of a food-based emulsifier. Modified kappa-carrageenan (KC-OSA) with different degrees of substitution (DS) (0.023 and 0.045) was produced, and their functional and structural properties were investigated. The results from FTIR and 1HNMR verified the successful occurrence of modification. The KC-OSA emulsions with both DS values were utterly stable after 30 days of storage, while KC failed to form emulsions. The viscosity, foaming properties, surface net charge, and gel opacity increased after modification and with an increase in its extent, while emulsion particle size and polydispersity index, gel melting temperature, and gel hardness decreased. Afterward, the KC-OSA (DS = 0.023) potential use was investigated as fat and egg yolk substitute in mayonnaise, which resulted in vegan mayonnaise samples with no phase separation after a month of storage at room temperature. Particle size measurements implied that the particle size of the mayonnaise sample was decreased with an increase in KC-OSA concentration. The results from the sensory evaluation showed that KC-OSA could be successfully implemented in low-fat vegan mayonnaise. The results from this study draw a bright horizon for the use of KC-OSA in the food industry.

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.

High-methylated pectin from walnut processing wastes as a potential resource: Ultrasound assisted extraction and physicochemical, structural and functional analysis.

The ultrasound-assisted extraction of pectin from walnut processing waste was optimized by Box-Behnken design. The highest extraction yield (12.78 ± 0.83%) was obtained at ultrasound power of 200 W, sonication time of 10 min, pH of 1.5 and LS ratio of 15 v/w. The resulting pectin in these conditions was rich in galacturonic acid (69.44%) and was high in degree of esterification (59.21%) which was confirmed by NMR and FTIR spectra. In addition, the molecular weight distribution analysis showed that the obtained pectin had a heterogeneous natural with low molecular weight (6.30-158.48 kDa). The XRD spectrum of the walnut pectin showed an amorphous structure with few crystalline portions. Furthermore, walnut green husk pectin had good emulsifying properties, water and oil holding capacities, and radical-scavenging activity. Given that the obtained result, the extraction of pectin from this by-product in addition to being able to reduce environmental problems, it can also provide financial benefits for the walnut production sector.

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.

Pistachio green hull pectin: Optimization of microwave-assisted extraction and evaluation of its physicochemical, structural and functional properties.

The optimal microwave-assisted extraction conditions of pistachio green hull (PGH) pectin (extraction yield of 18.13%) were in microwave power of 700 W, irradiation time of 165 s, and pH of 1.5. The physico-chemical, structural and functional properties of pectin was examined and the results showed that PGH pectin under optimum conditions was low methoxyl (about 12.1%) with molecular weight of 1.659 kg/mol, emulsifying activity of 58.3%, total phenolic content of 18.18 mg GalAE/g pectin and good surface activity (46.23 and 49.75 mN/m at 0.1 and 0.5% w/v). Also, high performance liquid chromatography analysis illustrated that the pectin is including galacturonic acid (66.0%), arabinose (26.2%), galactose (3.7%), rhamnose (2.7%) and xylose (1.0%). In addition, 1H NMR and FTIR spectrums confirmed the presence of pectin in obtained supenatnt. Surface morphology analysis and X-ray diffraction pattern showed that PGH pectin had a rough surface with crystalline structure.

A novel inverse numerical modeling method for the estimation of water and salt mass transfer coefficients during ultrasonic assisted-osmotic dehydration of cucumber cubes.

The objective of this paper was to study the moisture and salt diffusivity during ultrasonic assisted-osmotic dehydration of cucumbers. Experimental measurements of moisture and salt concentration versus time were carried out and an inverse numerical method was performed by coupling a CFD package (OpenFOAM) with a parameter estimation software (DAKOTA) to determine mass transfer coefficients. A good agreement between experimental and numerical results was observed. Mass transfer coefficients were from 3.5 × 10-9 to 7 × 10-9 m/s for water and from 4.8 × 10-9 m/s to 7.4 × 10-9 m/s for salt at different conditions (diffusion coefficients of around 3.5 × 10-12-11.5 × 10-12 m2/s for water and 5 × 10-12 m/s-12 × 10-12 m2/s for salt). Ultrasound irradiation could increase the mass transfer coefficient. The values obtained by this method were closer to the actual data. The inverse simulation method can be an accurate technique to study the mass transfer phenomena during food processing.

Effect of processing on aggregation mechanism of egg white proteins.

Egg white proteins (EWPs) are important components of many food products. To obtain optimal functionality, EWP aggregation needs to be controlled. Different treatments can lead to the formation of aggregates in diverse ways, depending on the parameters of the treatments. Recent articles on the effects of processing (heat treatment, alkali treatment, pulsed electric field, high pressure, ultraviolet irradiation, and high intensity ultrasound) on the aggregation of EWPs are reviewed. The relationships between the processing parameters and the aggregation mechanisms are discussed. The information may be helpful in controlling the aggregation mechanisms during the processing.

Effect of salts and nonionic surfactants on thermal characteristics of egg white proteins.

Effect of salts (Sodium chloride (NaCl), Sodium sulfate (Na2SO4), Ammonium sulfate ((NH4)2SO4), and nonionic surfactants (glycerol, tween20, tween80) on thermal properties of egg white proteins as a whole were investigated. Egg white solutions with additive (0, 0.5 and 1%) were collected after 0, 1 and 2min heat treatment. Physico-chemical properties of egg white proteins were evaluated by measuring heat coagulation time, solubility and turbidity of solution. Adding glycerol caused the most significant decrease in turbidity and increase in heat coagulation time and solubility of egg white, although Sodium Chloride had the least positive impact on physico-chemical properties of egg white under heat treatment. The Fourier transform infrared (FT-IR) spectroscopy analysis of heat treated egg white proteins as a whole with additives demonstrated changes in secondary protein structure, which are presented regarding the shape, intensity and position of FT-IR band. Meanwhile, it showed a good correlation with the physico-chemical properties consequences. Generally, the effect of nonionic surfactants were more noticeable than that of salts in preventing of egg white proteins aggregation under heat treatment. By improving thermal stability of egg white proteins, its usage in thermal processing industry can be evolved.

Effect of Lactobacillus casei- casei and Lactobacillus reuteri on acrylamide formation in flat bread and Bread roll.

The aim of this study was the evaluation of fermentation by lactic acid bacteria (LAB) contains lactobacillus (L.) casei- casei and L. reuteri on acrylamide formation and physicochemical properties of the Iranian flat bread named, Sangak, and Bread roll. Sangak and Bread roll were made with whole and white wheat flour, respectively. Whole-wheat flour had upper content of protein, sugar, ash, fiber, damaged starch and the activity of amylase than the white wheat flour. After 24 h of fermentation, the pH values of the sourdoughs made from whole-wheat flour (3.00, 2.90) were lower, in compared to sourdoughs prepared from white wheat flour (3.60, 3.58). In addition, in Sangak bread, glucose, and fructose were completely utilized after fermentation, but in bread roll, the reduced sugar levels increased after fermentation and baking that represent microorganisms cannot be activated and utilized sugars. Acrylamide formation was impacted by pH of sourdough and total reducing sugar (r = 0.915, r = 0.885 respectively). Bread roll and Sangak bread were fermented by L. casei- casei contained lowest acrylamide content, in two bread types (219.1, 104.3 µg/kg respectively). As an important result, the acrylamide content of Sangak bread in all cases was lower than in the Bread roll.

Modulating the textural characteristics of whey protein nanofibril gels with different concentrations of calcium chloride.

Protein nanofibrils with 10-20 nm diameters were formed by heating whey protein solution at pH 2.0. Nanofibrils solution was deacidified slowly through dialysis followed by adding different amounts of CaCl2 (0-80 mM) into the dialysis water resulting in formation of a soft viscoelastic gel over time. The gel fabricated from the nanofibrils solution dialyzed against distilled water with 0 mM CaCl2 had zero ash content. Fourier transform infra-red spectroscopy revealed a change in the pattern of hydrogen bond formation in gel network by calcium chloride. The higher the ash content of gels, the lower was the storage modulus and fracture stress of samples. Gels with higher ash contents had a more porous microstructure which was attributed to the diminished hydrophobic interactions and hydrogen bonding among nanofibrils by the action of chloride. Higher ash contents also led to higher water holding capacity of gels which was attributed to the influence of the strongly hydrated calcium ions that interacted with the non-charged regions of proteins via site-specific interactions.

Development of a novel yoghurt based on date liquid sugar: physicochemical and sensory characterization.

The addition effect of date liquid sugar (DLS, 1-9 % v/v) to yoghurt milk on the physical (colour, firmness and syneresis), chemical (pH, total titratable acidity (TTA), total phenolic content (TPC) and antioxidant activity), rheological (viscosity and flow behaviour), and sensory attributes was scrutinized. Results showed that the pH value decreased by increasing DLS concentration from 1 to 6 %, while the TTA decreased with an increase in DLS from 6 to 9 % (p < 0.05). The whey syneresis, firmness and viscosity values were considerably influenced by the DLS content and acidity of the yoghurts (p < 0.05). A noticeable increase in antioxidant activity and TPC was found by the increasing DLS content (p < 0.05). Yoghurts containing 6 % v/v DLS also had the lowest syneresis and the highest firmness among the different samples. Moreover, a pseudoplastic rheological behaviour was detected for all the produced yoghurts. An increase in DLS concentration of manufactured yoghurts led to an increase in a, b and total colour difference (TCD) values and a decrease in L value (p < 0.05). The sensory evaluation revealed that there was no significant different in the colour scores. However, the used panelists determined the yoghurt supplemented with 6 % DLS had the highest scores for other investigated attributes.

All-cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application.

All-cellulose nanocomposite (ACNC) film was produced from sugarcane bagasse nanofibers using N,N-dimethylacetamide/lithium chloride solvent. The average diameter of bagasse fibers (14 µm) was downsized to 39 nm after disk grinding process. X-ray diffraction showed that apparent crystallinity and crystallite size decreased relatively to an increased duration of dissolution time. Thermogravimetric analysis confirmed that thermal stability of the ACNC was slightly less than that of the pure cellulose nanofiber sheet. Tensile strength of the fiber sheet, nanofiber sheet and ACNC prepared with 10 min dissolution time were 8, 101 and 140 MPa, respectively. Water vapor permeability (WVP) of the ACNC film increased relatively to an increased duration of dissolution time. ACNC can be considered as a multi-performance material with potential for application in cellulose-based food packaging owing to its promising properties (tough, bio-based, biodegradable and acceptable levels of WVP).

Effect of refrigerated storage on the probiotic survival and sensory properties of milk/carrot juice mix drink

Background: There is a genuine interest in the development of probiotic milk and juice based beverages because they are a good-vehicle to deliver probiotic microorganisms to consumers. For this purpose, the viability and metabolism of four probiotic strains (Lactobacillus acidophilus LA5, Bifidobacterium lactis BB12, L. rhamnosus and L. plantarum) were studied in non-fermented milk and carrot juice mix drink. The drinks were evaluated in 5 days interval for viable cell count, pH, acidity, sedimentation and sensory quality during refrigerated storage at 4 ± 2ºC for up to 20 days. Results: The results showed that all strains had good viability in milk/carrot juice drink (88-98%), but L. acidophilus LA5 seemed more stable than three other strains. The levels of pH and acidity were ranged 5.33-6.6 and 0.13-0.31%, respectively. The drinks inoculated with L. rhamnosus and control (non-probiotic) showed more variation in pH and acidity. The most sedimentation was detected in drinks inoculated with L. rhamnosus, reaching 3.73 mL/10 mL sample. Sensory assessment indicated lowest acceptability in control and milk/carrot juice drink inoculated with L. rhamnosus, respectively. Conclusion: This study indicated that some probiotic bacteria can be applied by food producers to produce functional drinks with an increased shelf-life.

On the formulation design and rheological evaluations of pectin-based functional gels.

In the current study, formulation design and development of a novel pectin-based functional gel were investigated. Amidated low methoxyl pectin (ALMP), high methoxyl pectin (HMP), sorbitol, inulin, rebaudioside-A, gardenia, phloridzin, quercetin, apple flavor, and calcium chloride (as its dihydrated salt) were selected as general ingredients. Response surface methodology was applied to design different formulations and to investigate on their experimental responses. The oscillatory tests were carried out in 2 stages with ALMP, HMP, sorbitol, and inulin as the variables of the 1st stage and ALMP and calcium chloride as the variables of the 2nd stage. Results of the 1st stage indicated relatively similar behaviors throughout the frequency range applied for all of the samples studied (true gels). However, magnitudes of the 5 rheological parameters of this study (storage modulus, loss modulus, loss tangent, complex modulus, and complex viscosity) were affected by different variables (ALMP, HMP, inulin, and sorbitol concentrations). Experimental results confirmed that sorbitol could be omitted from the formula while inulin and HMP could be used at their highest levels studied. At the 2nd stage, only 2 formulas indicated a strong gel behavior and other formulas showed typical behaviors of weaker gels or those of the concentrated solutions. At the conclusion of this study, a finished gelled product formula was suggested with the application of the best levels of the ingredients. The resultant gel was found to be set rapidly with no syneresis and showed a potential to be considered as a functional gelled dessert.