Extraction of phenolic compounds from walnut green husk (Juglans regia L.) by Salting-Out extraction method.

Some factors in the salting-out extraction (SOE) method play a major role. The aim of this study was to investigate the interaction effects of the phase forming components and consequently select the best conditions to achieve a highly efficient recovery of phenolic compounds from walnut green husks (Juglans regia L.) using mixtures of ethanol and aqueous ammonium sulfate solutions. According to the results that were analyzed by response surface methodology, the optimal extraction conditions were obtained at ethanol: salt: water ratio of 34.8: 15.1: 54.4 (w/w) at a pH of 6-6.5 and 25 °C. At the optimal conditions, the overall phenolic and flavonoid content, and antioxidant activity were significantly higher than obtained by the conventional method. In addition, at a higher scale (i.e., 5 kg), similar results were obtained. Thus, it can be concluded that SOE has the potential to be scaled up for the simultaneous separation and purification of compounds from plant biomass. This paper is addressing extraction techniques, measurement, and characterization of new natural phenolic compounds from an agricultural by-product and valorization of waste.

Valorization of walnut green husk (Juglans regia L.) through sequential electrohydrodynamic extraction of pectin and phenolics: Process optimization and multidimensional analysis.

This study aimed to optimize the extraction of pectin and phenolics from walnut green husk using the electrohydrodynamic method (EHD) and assess its impact on the chemical structure and properties of pectin. A comparative analysis was conducted with acidified water as the conventional extraction method. The results revealed significant improvements under the optimal EHD conditions (36.8 min, 17.5 kV, 90 °C), leading to a remarkable increase of over 64 % in pectin yield and >20 % in total phenolic content in half the extraction time. Chemical analysis showed that pectin samples contain 1.4-1.7 % ash, 3.6-4.6 % protein, over 90 % carbohydrates, and a galacturonic acid content ranging from 67.7 to 68.2 g/g. Both extraction methods yielded pectin with a high methoxyl degree, comparable thermal stability, and amorphous structure. EHD treatment resulted in reduced molecular weight, degree of esterification, water-holding capacity, and emulsion stability of pectin while enhancing its solubility and emulsion capacity. In summary, EHD treatment significantly improved extraction yield and changed the functionality of pectin, particularly in terms of emulsion activity. This alteration should be considered when utilizing pectin for specific applications.

Influence of fatty acid-esterified waxy maize starch type and concentration on stability and properties of oil-in-water emulsions.

In the current study, native and different fatty acid-esterified waxy maize starches (octanoate, myristoate, and stearoate), followed by an OSA-potato starch (as an industrial emulsifier) were used to prepare sunflower oil-in-water (O/W) emulsion. The effect of emulsifier type and concentration were evaluated on properties of emulsions in terms of mean droplet size, droplet size distribution, and creaming index. To prepare the emulsion, the emulsifier to oil ratios of 1.25 and 0.5 for octanoate and industrial emulsifier (control) were considered as the selected formulations based on the lowest creaming index (2.63 and 0 %, respectively). The influence of various pHs and ionic strengths on droplet size, span and zeta potential value was similar for both produced emulsions. Therefore, the fatty acid-esterified starch could be suggested as a promising environmentally friendly alternative to industrial emulsifiers for fabrication of emulsions with similar stability.

Effect of sugar beet fiber and different hydrocolloids on rheological properties and quality of gluten-free muffins.

BACKGROUND: Extraction of pectin from sugar beet pulp is a side production line to recover value-added by-products in a sugar refining company. We aimed to evaluate the influence of depectinized and non-treated fiber on the quality of food. Pectin was removed from sugar beet pulp, and sugar beet fiber with and without pectin extraction (F and FP respectively) were replaced with rice flour in gluten-free muffins. To achieve a consistent texture, different hydrocolloids (carrageenan, xanthan gum, guar gum, locust bean gum (LBG), and tara gum) were added to the batter formula. RESULTS: The maximum batter viscosity was observed for the xanthan-containing formulation, followed by guar, tara, LBG, and carrageenan formulations. The highest hardness was recorded for baked muffins formulated with guar, followed by xanthan, carrageenan, tara, and LBG formula. Moisture retention was considerably increased in the presence of FP and LBG compared with muffins prepared by F and/or other hydrocolloids. However, muffins containing F showed the least hardness and highest cohesiveness, gumminess, springiness, and chewiness. The samples containing F represented lighter color, lower energy, and less porous in appearance compared with the FP formula. From a sensorial aspect, there was no significant difference between the F and FP formulas, but the control and sample with higher fiber content were not acceptable. CONCLUSION: This study showed that depectinized sugar beet fiber a by-product of sugar factories, has the possible use in formulation of gluten-free muffins with no adverse effects on its quality. © 2022 Society of Chemical Industry.

Physicochemical and sensory properties of malt beverage containing sugar beet saponins.

Aqueous two-phase system (ATPS) composed of polyethylene glycol (PEG) and K2HPO4 solutions was used to extract saponin from sugar beet root. Extraction yield, purity and foam capacity of saponin were optimized according to response surface methodology (RSM). Analysis of liquid chromatography-mass spectrometry (LC-MS) showed that purified saponins were composed of hederagenin, akebonoic acid and oleanolic acid. Addition of 0.02 g sugar beet root saponin to one liter of malt beverage caused a considerable increase in foam volume and stability compared to malt beverage samples containing 0.1 g/L propylene glycol alginate (PGA). Malt beverages containing saponin showed higher turbidity, bitterness and overall sensory acceptance. Moreover, no significant changes in malt drink pH and °Brix were observed due to saponin addition. Adding lemon flavor caused a decrease in foam stability and sensory acceptance of malt beverage containing saponin compared to PGA containing ones. Less saponin content is suggested for flavored malt drinks. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05517-x.

Chemical modification of waxy maize starch by esterification with saturated fatty acid chlorides: Synthesis, physicochemical and emulsifying properties.

In the current study, the physicochemical and emulsifying properties of modified waxy maize starch obtained through a new environmentally friendly method of esterification were evaluated. The starch modification was carried out in NaOH solution with different levels of octanoyl, myristoyl, and stearoyl chlorides. Increasing the fatty acid chlorides concentration led to the degree of substitution increment, while reaction efficiency and yield decreased. Based on fourier transform infrared spectroscopy results, the presence of two new bands of carbonyl (1740-1750 cm-1) and carboxyl (1570 cm-1) groups in the ester bond confirmed the successful starch esterification process. The level of 0.1 mL fatty acid chlorides/g of starch demonstrated the highest emulsifying properties. Upon esterification, the crystalline structure of amylopectin was destroyed, indicating no gelatinization features. Therefore, using the fatty acid chlorides in an alkaline condition could be suggested as a feasible way to modify waxy maize starch toward hydrophobicity increment with desirable properties.

Effect of combination of ultrasonic treatment and anti-solvent methods as a high-efficiency method of nanoparticle production on the tragacanth gum properties.

Gum tragacanth nanoparticles were prepared using a combination of intense ultrasound energy and anti-solvent precipitation methods in this research. Results showed that smaller particles were produced by increasing sonication time. As well, increasing the sonication power led to smaller particles, however, increased aggregation. Accordingly, tragacanth solutions with 0.5 and 1% (w/v) concentrations were prepared and mixed with ethanol (ratio 1:10 v/v) after ultrasound treatment with two different drop-wise and direct methods to investigate the effect of anti-solvent addition method on the precipitation of tragacanth particles. The nanoparticle images showed that the concentration of the 0.5% tragacanth solution and the direct mixing method was suitable for particle production with desirable size (72 ± 10 nm) and uniformity. FTIR, XRD, and STA studies showed that the tragacanth chemical composition did not change, and only its particle size decreased. Investigation of wettability showed a contact angle of 88.9 ± 1.7 degrees for nanoparticles providing partial wetting of the particles at the interface. Investigation of the solution viscosities of 0.5% tragacanth gum and tragacanth nanoparticles showed that the viscosity of the nanoparticles solution was significantly lower than that of the tragacanth (p < 0.05) indicating the intense effect of ultrasonication on this property. It can be concluded that the high viscosity of tragacanth gum is not due to its chemical composition but is due to its complex structure.

Stabilization of Pickering emulsion using tragacanth nanoparticles produced by a combination of ultrasonic and anti-solvent methods.

BACKGROUND: Because of the high surface/volume ratio in nanometric size particles, they exhibit novel functional properties in many industries, such as emulsion stabilization. Tragacanth nanoparticles (TNPs) were prepared in this research, applying intense ultrasound energy followed by anti-solvent precipitation in ethanol. RESULTS: Investigation of wettability showed a contact angle of 88.9 ± 1.7° for TNPs, providing partial wetting of the nanoparticles at the oil-water interface. Pickering emulsions were prepared using TNPs at different oil contents. Also, emulsions containing tragacanth gum solution were prepared as control emulsions. Results showed that the viscosity of the emulsions prepared by the TNPs was significantly lower than those of the control emulsions. Microscopic images showed that the size of the emulsion droplets decreased by increasing the nanoparticle concentrations. Evaluation of the stability of the emulsions showed that changes in the average diameter of the emulsion droplets stabilized by nanoparticles were not significant after 1 month of storage at room temperature. In contrast, the size of the droplet of control emulsions increased over the 30 days of storage. Thermal and mechanical stresses confirmed the effect of the concentration of TNPs and the oil ratio on the stability of the emulsions. CONCLUSION: The use of TNPs as a natural biopolymer is a promising approach in emulsion systems to prevent coalescence and increase the stability of the Pickering emulsions. © 2021 Society of Chemical Industry.

Phytochemical Composition, Antimicrobial, Anticancer Properties, and Antioxidant Potential of Green Husk from Several Walnut Varieties (Juglans regia L.).

Husk powder was prepared from seven varieties of walnut fruit and their hulling rate, chemical compounds, and total phenolic contents were evaluated. The apolar and polar extracts were prepared, respectively, from hexane and a hydroethanolic solvent, while qualitative and semi-quantitative analyses were performed by GC/MS and UHPLC-PDA-HRMS/MS. The antioxidant, antimicrobial, and antitumor properties of green walnut husk were also evaluated. The total content of phenolic compounds varied between the varieties, ranging from 35.2 ± 0.9 to 58.0 ± 0.0 mg/g gallic acid equivalent of dry husk weight (dw). The apolar extract was found to contain alkanes, tocopherols, sterols, and fatty acids, including oleic, linoleic, and linolenic, while the polar extract showed the presence of phenolics including salicylate glucuronide, taxifolin, catechin, and quercetin isomers. The antioxidant power obtained by the PAOT (total antioxidant power) method for the husk powders ranged from 256.5 ± 5.9 to 746.8 ± 6.9 score/g dw, and seemed consistent with the total phenolic content and the results obtained by the classic antioxidant test with DPPH. The walnut husk also showed an antibacterial effect against Gram-negative and Gram-positive bacteria and cytotoxic potential against HepG2. Among the selected varieties, the green Saman had the highest antioxidant properties, while the Saman with a brown color had the lowest.

Efficiency of calcined Aluminum-Magnesium layered double hydroxide for adsorption of aflatoxin M1 from solution and matrix of milk.

Detoxification of aflatoxin M1 from solution and milk using layered double hydroxides was investigated. The Aluminum-Magnesium layered double hydroxide (Al-Mg LDH) and Iron-Magnesium layered double hydroxide (Fe-Mg LDH) were selected in their calcined and non-calcined forms to evaluate the effect of the calcination on detoxification. These materials were produced using the co-precipitation method. Preliminary adsorption tests confirmed use of Al-Mg LDH as the selected adsorbent. Characteristics of the adopted adsorbent were studied and confirmed by XRD, FTIR, SEM, and BET methods. Effects of the initial content of aflatoxin, amount of the adsorbents and detoxification time were investigated. Influence of the adsorbents on the nutritional aspects of milk were also studied. The study showed that while the non-calcined forms of LDH were not able to adsorb aflatoxin M1 more than 23%, the calcined form of Al-Mg LDH exhibited 100% adsorption in the solutions and about 70-100% in the contaminated milk samples. The reason is pointed to the fact that calcination of Al-Mg LDH considerably increased the surface area, the total pore volume, and the pore size of the material. Multivariate regression analysis and calculation of the Pearson correlation factor showed that the remained aflatoxin at each time was more strongly correlated with the initial amount of aflatoxin and the elapsed time and less strongly with the amount of the adsorbent. It was found that the adsorption isotherms fitted to the Freundlich equation with a high adsorption capacity of 555.5 mg g-1. PRACTICAL APPLICATION: This study is focused on examining ability of layered double hydroxides (LDH) for adsorbing AFM1 . LDHs are promising layered materials due to some of their interesting characteristics, such as ease of synthesis and uniqueness of structure. In practice, results of this study can be used for detoxification of aflatoxin, especially in milk, at high efficiency in shorter time durations.

Rheological and functional properties of asafoetida gum.

The asafoetida gum was extracted and purified from oleo-gum-resin of Ferula assa foetida root and characterized by high pressure anions exchange chromatography after acidic hydrolysis. It was composed of Gal:Ara:Rha:GlcA with the ratio 11.5:5.0:2.1:1.0. This monosaccharide composition was found similar to that of a commercial Arabic gum which exhibited a Gal:Ara:Rha:GlcA ratio of 11.7:5.4:3.2:1.0. As the Arabic gum is currently used for its emulsifying properties, the two gums were evaluated for their functional and rheological behaviors. Surface and interfacial tensions values were lower for asafoetida gum compared to Arabic gum. Critical micelle concentration was achieved at concentrations of 0.5% w/w and 1% w/w for asafoetida and Arabic gums, respectively. Values of emulsion capacity, emulsion stability and foaming properties were considerably higher for asafoetida gum in contrast to emulsion activity index that was lower than that of Arabic gum. As those of Arabic gum, solutions of asafoetida gum (2-30% w/w) exhibited Newtonian flow behavior at shear rates between 1 and 500 s-1. Apparent viscosities of Arabic and asafoetida gums were close and logically decreased by increasing temperature (10-80 °C). Higher viscosities were achieved at higher pH and CaCl2 concentrations.

Effect of electrohydrodynamic technique as a complementary process for cellulose extraction from bagasse: Crystalline to amorphous transition.

Electrohydrodynamic technique (EHD) has lately received considerable attention as an important non-thermal method used for food processing. In this work the effect of EHD on physicochemical properties of cellulose extracted from bagasse was investigated. A three-step process was chosen to extract cellulose fibers, which was performed under a high voltage electric field at the beginning of each step. The cellulose fibers were then characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Thermogravimetric Analysis (TGA). The morphological evaluation revealed that the cellulose fibers have smaller diameter and larger length compared to the microcrystalline cellulose. Moreover, according to the XRD patterns and FTIR spectrum, EHD-treated fibers mainly showed an amorphous structure, and contained a low crystalline fraction. The amorphous structure of cellulose fibers was confirmed by TGA analysis which revealed the presence of higher proportion of amorphous cellulose fraction causes early onset of thermal decomposition.

Fabrication of whey proteins aggregates by controlled heat treatment and pH: Factors affecting aggregate size.

Protein aggregates can be formed by heating globular proteins above the thermal denaturation of the proteins. These aggregates can be used as delivery systems or to modulate the physicochemical and sensory properties of food products. In this study, the effects of heat treatment (15 min at 80 °C), pH adjustment (between 4 and 9), aging at different temperatures (between 10 and 60 °C) and the rate of acidification (pH decreased from 6.25 to 4 at 5 different rates) on whey proteins aggregates were studied. The results indicated that these treatments led to creation of aggregates with different sizes (0.72-5.1 µm). Heat treatment and reducing the pH down to nearly 4 led to an increase in the size of aggregates. At pH < 7, by increasing the aging temperature, the size of aggregates increased (without heat treatment). In the heat treated samples with pH < 9, increasing the aging temperature led to an increase in the size of aggregates. Also larger aggregates were formed by increasing acidification rate. The amount of insoluble whey proteins aggregates increased as a result of applying heat treatment, decreasing pH and increasing aging temperature. The results of this study can be used for fabrication of whey proteins aggregates with specific size and functionality.

Structural characterization and thermal behavior of a gum extracted from Ferula assa foetida L.

The gum asafoetida, an oleo-gum-resin from root of Ferula assa foetida, was extracted through alcoholic procedure followed by water extraction and then biochemically characterized using colorimetric assays, Fourier infrared spectroscopy, gas chromatography coupled to mass spectrometry, and 1D and 2D nuclear magnetic resonance. The gum was mainly composed of carbohydrates (67.39% w/w) with a monosaccharide distribution of 11.5: 5.9: 2.3: 1 between Gal, Ara, Rha and GlcA (molar ratio) and proteins (arabinogalactan protein). The polysaccharide consisted of a (1→3)-ß-d-galactan backbone ramified predominantly from O-6 but also from O-4 and O-4,6. Side chains included terminal-α-l-Araf, terminal-α-l-Rhap, (1→3)-α-l-Araf, (1→5)-α-l-Araf, terminal-ß-d-Galp, ß-d-GlcA and traces of (1→4)-ß-d-GlcA. X-ray diffraction pattern showed a semi crystalline microstructure. Thermal behavior of the gum was evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed temperatures below and upper 200°C as dominant regions of weight loss.

Stability of astaxanthin-loaded nanostructured lipid carriers in beverage systems.

BACKGROUND: Nanostructured lipid carriers (NLCs) offer many potential benefits for incorporating lipophilic molecules into clear to opaque food systems. This study examined the stability of astaxanthin-loaded NLCs (Ax-NLCs) in model (solutions with 0 or 12% sucrose; pH 3, 7), semi-actual (whey) and actual (non-alcoholic beer) beverages during 30-60 days storage at 6 or 20 °C. RESULTS: Ax-NLCs (Z-average size: 94 nm), containing α-tocopherol and EDTA as antioxidants, were stabilised with Tween 80 and lecithin, and mixed with the aforementioned beverages at the volume ratio of 3:97. The presence of sucrose, improved the physical stability of Ax-NLCs in acidic model beverage. No astaxanthin loss and particle size growth were observed for Ax-NLCs-added whey. Carbonation and/or thermal pasteurisation of NLCs-added beer led to a major increase in its particles size and astaxanthin loss. Stability of Ax-NLCs in non-pasteurised CO2 -free beer improved at low storage temperature. The organoleptic quality of NLCs-added beers was still acceptable. CONCLUSION: These results indicate that NLCs containing hydrophobic nutraceuticals have potential to be used for functional beverages/foods development. © 2017 Society of Chemical Industry.

Stability of astaxanthin-loaded nanostructured lipid carriers as affected by pH, ionic strength, heat treatment, simulated gastric juice and freeze-thawing.

Nanostructured lipid carriers (NLCs) offer many potential benefits for incorporating lipophilic molecules into clear/opaque food systems. In this study, the influence of pH, ionic strength, thermal treatment, simulated gastric juice (SGJ), and freeze-thawing on the stability of astaxanthin-loaded NLCs (Ax-NLCs) was examined. Ax-NLCs (containing α-tocopherol and ethylenediaminetetraacetic acid as antioxidants) were stabilized with Tween 80 and lecithin (Z-average size: 94 nm), and studied for the above mentioned purpose. The size of Ax-NLCs increased at low pH values (≤5), high NaCl concentrations (≥50 mM), and slightly at SGJ, mainly because of decreasing the ζ-potential. Moreover, thermal treatment at 80/90 °C led to an increase in Ax-NLCs size. Glycerol was found as an appropriate cryoprotectant for preventing aggregation of Ax-NLCs during freeze-thawing. pH, ionic strength, heat and SGJ had no drastic effects on the chemical stability of astaxanthin in NLCs. These results have valuable implications for the utilization of food-grade NLCs.

Improving the emulsifying properties of ß-lactoglobulin-wild almond gum (Amygdalus scoparia Spach) exudate complexes by heat.

BACKGROUND: The present study aims to investigate the advantageous effects of wet heating, BLG (ß-lactoglobulin)/Ang (Angum gum) ratio, and pH (normal pH of mixed BLG and Ang solutions, pHc > pH > pHΦ1 ) on the emulsifying properties of wet-heated ß-lactoglobulin-wild almond gum exudate (Amygdalus scoparia Spach) mixture over those of electrostatic counterparts. RESULTS: Covalent linkage of BLG-Ang conjugates was confirmed by SDS-PAGE and FTIR analysis. Emulsion activity (EA), emulsion stability (ES), and droplet size characteristics of emulsions were significantly (P < 0.05 and P < 0.01) affected by electrostatic/wet-heating, biopolymer ratio, pH, and their interactions. The electrostatic complexes with pHc > pH > pHΦ1 exhibited higher EA and ES values for all the biopolymer ratios investigated than their electrostatic counterparts with pH after mixing. However, these values for the wet-heated samples at pH after mixing were found to be higher than those of the samples subjected to heat treatment at pHc > pH > pHΦ1 . Based on the results obtained, it was concluded that E/1:2/3.80 and W/1:2/6.69 were the two complexes with finer droplet size distributions after preparation (26.72 ± 3.71 and 15.27 ± 1.01 µm, respectively) and after one week of storage at 4 °C (30.71 ± 1.57 and 28.79 ± 0.56 µm, respectively) than others. Apparent viscosities of electrostatic and wet-heated complexes and emulsions made with the complexes were measured. CONCLUSION: Protein-polysaccharide interactions can be used as an efficient way for producing novel emulsifiers/stabilisers after heat treatment. © 2016 Society of Chemical Industry.

Effect of glycosylation with gum Arabic by Maillard reaction in a liquid system on the emulsifying properties of canola protein isolate.

In this research, the improvement of emulsifying properties of chemically modified canola protein isolate (CPI) with gum Arabic (GA) through Maillard reaction under natural pH at 90°C was investigated. The stability, rheology and morphology of oil-in-water emulsions stabilized by conjugate of two biopolymers were evaluated by determination of droplet size, emulsifying activity (EAI), emulsifying stability (ESI) and creaming indices. The conjugate-stabilized emulsion showed smaller mean droplet size and lower creaming index values which were more effective to stabilize the emulsion compared to CPI and mixture of two biopolymers especially if pH was near the isoelectric point of CPI or when emulsions heated from 30 to 90°C. Moreover, our results demonstrated that EAI, ESI and viscosity of emulsion for CPI-GA conjugate were significantly more than those of CPI-GA mixture and CPI. These results suggested that Maillard reaction could be one of the most promising approaches to improve emulsifying properties of CPI for food applications.

Preparation of chemically modified canola protein isolate with gum Arabic by means of Maillard reaction under wet-heating conditions.

The aim of this study was to produce covalently attached conjugate between canola protein isolate (CPI) and gum Arabic (GA) in aqueous solutions via the Maillard reaction at 90°C in a model system consisting of 2% CPI and 1, 2 or 4% GA. Upon decreasing of free amino group content in the glycosylated CPI to 72%, a new band near the loading end of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a shift of CPI peak in high performance size exclusion chromatography confirmed that the covalent attachment of CPI to GA was successful. The results of secondary structure analysis suggested that grafted CPI had decreased α-helix and ß-sheet levels and increased random coils level. The solubility of CPI at isoelectric point was improved remarkably after grafting with GA. The optimal conjugation conditions chosen from the further experiments were 1% of GA, 90°C and reaction time 15min.

Fabrication of electrospun almond gum/PVA nanofibers as a thermostable delivery system for vanillin.

In this study, the fabrication of vanillin incorporated almond gum/polyvinyl alcohol (PVA) nanofibers through electrospinning has been investigated. Electrospinning of only almond gum was proved impossible. It was found that the aqueous solution of almond gum/PVA (80:20, concentration=7% (w/w)) containing 3% (w/w) vanillin could have successfully electrospun to uniform nanofibers with diameters as low as 77nm. According to the thermal analysis, incorporated vanillin in almond gum/PVA nanofibers showed higher thermal stability than free vanillin, making this composite especially suitable for high temperature applications. XRD and FTIR analyses proved the presence of vanillin in the almond gum/PVA nanofibers. It was also found that vanillin was dispersed as big crystallites in the matrix of almond gum/PVA nanofibers. FTIR analysis showed almond gum and PVA had chemical cross-linking by etheric bonds between COH groups of almond gum and OH groups of PVA. Also, in the nanofibers, there were no major interaction between vanillin and either almond gum or PVA.