Multi-layer encapsulation of pumpkin (Cucurbita maxima L.) seed protein hydrolysate and investigating its release and antioxidant activity in simulated gastrointestinal digestion.

Because of their high protein content, easy access and low cost, pumpkin seeds are a valuable raw material for the preparation of antioxidant protein hydrolysates. Micro-coating is an effective method to protect bioactive compounds against destruction. In order to strengthen the alginate hydrogel network loaded with pumpkin seed protein hydrolysate (PSPH), CMC was added as part of its formulation in the first step, and chitosan coating was used in the second step. Then, swelling amount, release in the simulated gastrointestinal environment (SGI), antioxidant activity after SGI, Fourier transform infrared spectroscopy (FTIR), zeta potential, dynamic light scattering (DLS), polydispersity index (PDI) and scanning electron microscopy (SEM) of the samples were evaluated. The results showed that, the swelling amount of the chitosan-alginate hydrogel was lower than the chitosan-alginate-CMC sample, and with the increase in chitosan concentration, the swelling amount decreased. The release amount in the chitosan-alginate sample was higher than that in the chitosan-alginate-CMC sample, and with the increase in chitosan concentration, the release rate decreased. Also, the amount of release increased with the passage of time. The highest antioxidant activity belonged to the chitosan-alginate sample in SGI, and it increased with increasing the chitosan concentration. All findings demonstrated that the use of multi-component hybrid systems is a useful method for the protection of bioactive compounds against destruction, their antioxidant activities and their release behavior.

Increasing Antioxidant Activity in Food Waste Extracts by ß-Glucosidase.

Research background: Food by-products such as onion peels and olive leaves are rich in bioactive compounds applicable as natural and low-cost sources of antioxidants. Still, these compounds mainly exist in glycosylated form. Often, hydrolysis of glycoside compounds increases their antioxidant activity and health benefits. However, not many studies have been done concerning the ß-glucosidase effect, specifically from Aspergillus niger, on glycosylated compounds within these by-products. Also, changes in the antioxidant activity of the mentioned by-products under the effect of ß-glucosidase have not been reported yet. Therefore, this study considers the effect of A. niger ß-glucosidase on glucoside compounds and the antioxidant activity of onion peel and olive leaf extracts. Experimental approach: The antioxidant activity of the extracts was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Also, glucose, total phenolic and flavonoid contents were measured. Moreover, TLC and HPLC analyses were performed before and after the enzymatic hydrolysis. Results and conclusions: The obtained results showed an increase in the extract antioxidant activity after treatment. Also, ß-glucosidase increased the glucose content of the extracts. The thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) results showed the ß-glucosidase efficacy to hydrolyze quercetin glucosides in onion peel extract, and the quercetin concentration increased from (0.48±0.04) mg/mL in the untreated extract to (1.26±0.03) mg/mL in the treated extract (0.5% m/V) after 3 h of enzymatic hydrolysis at 45 °C. Also, the content of quercetin-3-O-glucoside increased considerably from (1.8±0.1) to (54±9) µg/mL following the enzyme treatment. Moreover, oleuropein in olive leaf extract (1% m/V) was hydrolyzed completely from (0.382±0.016) to 0 mg/mL by ß-glucosidase for 24 h at 50 °C. Novelty and scientific contribution: This study showed that A. niger ß-glucosidase, as a stable enzyme, hydrolyzed quercetin and oleuropein glycosides in onion peel and olive leaf extracts. Thus, A. niger ß-glucosidase is a good candidate for processing the food waste and extracting valuable bioactive compounds. Also, the treated extracts with higher antioxidant and biological activity, and without bitter taste can be applicable as potent, natural and cost-effective antioxidants in the food industry.

Estimation of oxidative indices in the raw and roasted hazelnuts by accelerated shelf-life testing.

To estimate the oxidative stability of the raw and roasted hazelnuts, accelerated shelf-life testing (ASLT) was used at elevated temperatures (55, 65 and 75 °C) at water activity (aw) of 0.43. Chemical parameters, including peroxide value (PV), para-anisidine value, and total oxidation value were measured to estimate the oxidative stability of the samples using Arrhenius model. In addition, the samples were maintained for 8 months in a real condition at 20-30 °C (long-term shelf-life testing) for validating the results obtained from short-term ASLT. The maximum activation energy (Ea, 78.76 kJ/mol °K) and Q10 (1.871) was obtained for PV in raw hazelnuts, while the minimum Ea (53.36 kJ/mol °K) and Q10 (1.552) were recorded for PV in roasted hazelnuts, indicating the negative effect of roasting process on the oxidative stability of the samples. In order to validate the estimations, the values predicted by short-term ASLT for each oxidation index were plotted versus their corresponding values in actual storage. The results showed good correlation coefficients (R2 = 0.91-0.98), confirming the fitness of the Arrhenius model to predict the oxidative indices of the samples during normal storage.

Stability and structural properties of bee pollen protein hydrolysate microencapsulated using maltodextrin and whey protein concentrate.

In this research, the bee pollen protein hydrolysate was microencapsulated by spray drying using maltodextrin (MD), whey protein concentrate (WPC) and a mixture of both compounds. For this purpose, the bee pollen was hydrolysed by alcalase (enzyme concentration of 1.5%) at 50 °C and pH 8 during 3.95 h, and then freeze-dried. The hydrolysed protein and wall materials were used in ratio of 1:10 (w/w). The wall materials included maltodextrin 2%, WPC 2%, as well as maltodextrin and WPC mixtures with 3:1 ratio. The resulting capsules were exposed to UV radiation for 48 h to accelerate the oxidation. The results showed that the capsule prepared using maltodextrin and WPC mixture showed the highest DPPH radical scavenging during exposure to UV radiation. Based on the FTIR spectroscopy results, the wall containing maltodextrin and WPC mixture showed the best performance in maintaining the chemical structure of hydrolysed protein. The SEM results indicated that the microcapsules prepared with WPC and maltodextrin mixture as wall material showed uniform and smoother wall than those prepared with maltodextrin alone. Finally, it was found that the maltodextrin and WPC mixture was the best wall with an appropriate protective capability for the microencapsulation of hydrolysed proteins and their protection against UV radiation.

The formulation optimization and properties of novel oleuropein-loaded nanocarriers.

The present study sought to encapsulate oleuropein as a nutraceutical compound in order to investigate its physical properties and stability. We extracted the phenolic compounds of virgin olive leaf by ethanol-water and acetone-water solvents. The purity of this extract was confirmed by analytical high-performance liquid chromatography using oleuropein standard. Oleuropein was encapsulated with different components (lecithin, linoleic acid, glycerol monostearate, soybean oil, and Tween 80), and the effect of their contents on oleuropein-nanostructured lipid carrier (NLC) characteristics was checked by dynamic light scattering test. Moreover, several features of the optimal nanocarrier, including zeta potential, structural, morphology, stability, as well as thermal behavior were studied. The results of optimal NLC exhibited a high zeta potential as well as supreme stability versus aggregation. Thermal study indicated that oleuropein was well embedded into NLCs. The scanning electron microscope images showed that NLC samples had many spherical particles in the form of chain structure. The stable nanocarriers did not exhibit any oleuropein leakage following their analyses for 90 days at - 18, 6, and 25 °C in aqueous suspension.

Investigation effects of extracted compounds from shell and cluster of pistachio nut on the inactivation of free radicals.

Essential oils (EOs) are known for uses in various fields such as perfume, cosmetic, pharmaceutical and food industries. Agricultural wastes are among the resources of EOs that produced and disposed of in large quantities annually. Hence, in this study, for the first time, EOs available from pistachio fruit [fruit pistachio shells (FPS) and fruit pistachio cluster (FPC)] were used to the extraction of EOs. The Clevenger device and distilled water were used to extract EOs. The amount of total phenolic compounds (TPC) by Folin-ciocalteu reagent and the radical scavenging ability (RSA%) of FPS and FPC extracted by the soaking method were also measured. The RSA% of EOs and extracts in the presence of DPPH free radicals was evaluated by the IC50 index. Chemical composition of EOs detected by mass spectrometric gas chromatography. Notwithstanding amounts of extraction efficiency by water in the soaking method from FPS and FPC was 4.6% and 3.2% respectively, EOs extraction efficiency from FPC and FPS was 2.10% and 0.13% respectively. TPC in FPS and FPC was 958.38 and 796.25 mgGA/100g dry material respectively. The amount of IC50 of FPS was 3760.69 ppm and near to RSA% of BHT (2354.36 ppm). Statistical difference was observed between the RSA of EOs and positive control antioxidant (P < 0.05). The RSA of antioxidant extracts and TPC showed positively correlated. The major compounds identified in FPS were the D-limonene, α-thujene and terpinolene, abundance respectively, and the major components of FPC were α-thujene and α-pinene, abundance respectively.

Controlled enzymatic hydrolysis of pollen protein as promising tool for production of potential bioactive peptides.

In the present study, response surface method was used to optimize hydrolysis condition to generate potential bioactive peptides from pollen protein using pepsin (pepsin hydrolysated pollen-PHP) and trypsin (trypsin hydrolysated pollen-THP). Then PHP and THP prepared under optimized conditions were analyzed by size-exclusion chromatography. The fractions possessing the maximum ACE-inhibitory, DPPH radical scavenging, and ferric-reducing power were further purified by RP-HPLC. A heterogeneous composition of hydrophobic and hydrophilic peptides in both fractions was obtained. Finally, peptide sequences in active fractions of PHP and THP were identified by mass spectrometry in tandem. All the identified peptides had herbal protein origins. These were 6-21 amino acids in length, and Glycine and Alanine were two main hydrophobic amino acids present in their sequences. The results proved that using controlled enzymatic hydrolysis of pollen protein is possible to generate bioactive peptides with high ACE-inhibitory and antioxidant activity in final product. PRACTICAL APPLICATIONS: Pollen is well-known as an interesting protein source. Compared to other types of hydrolysis, enzymatic hydrolysis of vegetable proteins has few or no undesirable side reactions or products. In this study, controlled enzymatic hydrolysis of pollen protein was applied as a suitable method to produce bioactive peptide. The results proved that using controlled enzymatic hydrolysis of pollen protein is possible to generate bioactive peptides with high ACE-inhibitory and antioxidant activity in final product. This product can be used as functional and health promoting ingredient in different food formulations.

Fabrication of ß-carotene loaded glucuronoxylan-based nanostructures through electrohydrodynamic processing.

Various concentrations of ß-carotene (2.5-20% w/w dry mucilage weight) were loaded within Cydonia oblonga mucilage (COM) which further processed through electrohydrodynamic processing (EHP) to attain BC-Loaded nanostructures of high thermochemical stability. The BC loaded COM systems were characterized in terms of droplet size, rheological properties, surface tension, and electrical conductivity and their subsequent impacts on the morphology and physicochemical attributes of the produced nanostructures were studied. Increasing the ß-carotene content, increased the viscosity and droplet size of colloidal systems but diminished their conductivity and surface tension. A transition from monomodal to bimodal size distribution was also observed at higher levels of ß-carotene incorporation. In the case of EHP-produced nanostructures, scanning electron microscopy observations revealed a transition from nanoparticle to nanofiber by increasing the BC content from 2.5 to 20%. At lower concentrations of BC (2.5 and 5%) electrospraying was the dominant phenomenon that resulted in producing homogenous nanoparticles while the beaded fibers and nanofiber structures were obtained at 10 and 20% concentrations of BC, respectively. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and encapsulation efficiency of the produced nanostructures revealed successful encapsulation of BC into the COM polymer structure through EHP. The results of these assessments showed that the nano-particles comprising BC had more homogenous structure and higher encapsulated BC compared to the BC-loaded nano-fibers. The results of X-ray diffraction (XRD) and differential scanning calorimetry (DSC) measurements revealed amorphous structure of the produced nanostructures. Thermogravimetric assessments corroborated the higher thermal stability of BC loaded nanostructures compared with the free BC. These results provided novel information on the ability of COM in encapsulating bioactive agents through electrohydrodynamic processing.

Encapsulation of EPA and DHA concentrate from Kilka fish oil by milk proteins and evaluation of its oxidative stability.

Glyceride product from lipase-catalyzed hydrolysis of fish oil (large-scale) is a rich source of n-3 PUFA (49.62%); but it is prone to oxidation. Our aim was to encapsulate this product by a mixture of whey powder and sodium caseinate (4:1) as a new wall material. The emulsification was done using ultrasonication in different powers (180-380 W) and times (1-3 min) and, then, the emulsions were freeze-dried to obtain the powders. Based on encapsulation efficiency, sonication (88-94%) could inhibit the presence of oil at the surface of powder particles in comparison with the samples prepared without sonication (control, 68%). The highest oxidation rate and the lowest L-value were found for the unencapsulated glyceride product stored in air atmosphere followed by the control powder, the powders from sonication treatment and the unencapsulated glyceride product under N2, respectively. In the case of oxidative stability of the samples, the sonication time was more significant than sonication power. According to our results, a sonication treatment of 380 W for 3 min was recommended to prepare parent emulsions during fish oil encapsulation.

Production of antioxidant peptides through hydrolysis of medicinal pumpkin seed protein using pepsin enzyme and the evaluation of their functional and nutritional properties.

BACKGROUND: A hydrolyzed protein composition is a mixture of peptide and amino acids that have been achieved through hydrolysis by the enzyme from different sources, acid or caustic soda. These peptides show important health improving properties including anti-oxidation, antimicrobial, anti-cancer, anti-diabetic, anti-hypertensive activity. METHODS: The aim of the present study was to hydrolyze the protein extracted from medicinal pumpkin seed (Cucurbita Pepo Con. Pepo Var Styriaca) seed meal by pepsin enzyme to obtain bioactive peptides with the highest antioxidant capacity. For this, response surface method (RSM) and central composite design were used at different enzyme concentrations (1%-2%), hydrolysis times (2-5 hours), and temperatures (30-40 °C) as independent variables. Then, the functional properties (emulsifying capacity, foaming capacity, water absorption capacity, and oil absorption capacity), heat and pH stability, and amino acid analysis were measured for the optimum treatment. RESULTS: 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging capacity of peptides achieved in optimum conditions (82.07%) was highly similar to the results predicted by the software (80.31%) and their functional properties were significantly different from the initial protein (P > 0.050). Amino acid profile showed that the antioxidant capacity of the hydrolysates could be due to the total hydrophobic amino acid content that accounts for 39.85% of total amino acids in pumpkin seed meal. CONCLUSION: According to the results, pumpkin seed meal hydrolysates, with outstanding functional properties, can be used in different food formulation to improve their physical and chemical properties and extend their shelf life, and as antihypertensive and antioxidant agents in the prevention of cardiovascular disease.

Production of antioxidant peptide fractions from a by-product of tomato processing: mass spectrometry identification of peptides and stability to gastrointestinal digestion.

In this study, proteins were extracted from tomato seeds, the main by-product of tomato processing. The incubation for 138.62 min coupled with 3% alcalase was observed to be optimum to produce a tomato seed protein hydrolysate (TSPH) with the highest antioxidant properties. Under these conditions, predicted TSPH activities were 62.99% scavenging of DPPH radicals and 54.81% reduction of phosphomolybdate. Separation of TSPH by ultrafiltration provided three fractions (UF1-UF3) of which, UF3 (< 3 kDa) showed the strongest activity (73.15% DPPH scavenging and 60.1% phosphomolybdate reduction). UF3 was further separated by RP-HPLC into sub-fractions F1-F6. Biological testing found that F2 and F4 were the most active in scavenging DPPH radicals (60.36 and 21.23%) and reducing phosphomolybdate (57.3 and 48.0%). LC-ESI-MS/MS analysis showed that the higher activity of F2 might be explained by the presence of more peptides that contained tyrosine and histidine, known to enhance antioxidant activity through hydrogen or electron transfer. In the simulated gastrointestinal digestion test, peptides in F2 were more resistant compared to those in F4. These findings indicate that peptide fraction F2 might be more useful in the formulation of functional foods because of its greater antioxidant activity and resistance to digestion.

Fermented rapeseed meal is effective in controlling Salmonella enterica serovar Typhimurium infection and improving growth performance in broiler chicks.

The aim of present experiment was to assess the effects of fermented rapeseed meal (FRSM) on Salmonella enterica serovar Typhimurium (S. Typhimurium) colonization and growth performance in broiler chicks. Two hundred forty day-old male Cobb 500 broiler chicks were divided into six experimental treatments with four replicates and 10 birds per each. The treatments were including two positive and negative controls which birds received a basal corn-soybean diet as well as four others which birds received the diets that rapeseed meal (RSM) or FRSM was replaced with soybean meal at 50 and 100% levels. All chicks except the negative control birds were challenged orally with 105 CFU of S. Typhimurium at 3days of age. Results showed that birds were fed FRSM had significantly greater lactic acid bacteria populations and lesser S. Typhimurium colonization in ileal and cecal sections compared to others (P<0.05). The less percentage of liver and bursa of fabricius was belonged to negative control group. At 10day, feeding chicks with diet containing FRSM, but not RSM, significantly decreased the organ invasion by S. Typhimurium (P<0.05). Heterophil to lymphocyte ratio was significantly lesser in chicks were fed FRSM compared to those fed RSM or positive control (P<0.05). Birds were fed FRSM had significantly higher weight gain and better feed conversion ratio compared to those birds were fed RSM (P<0.05). The findings of present experiment concerning positive effects of feeding FRSM on reducing S. Typhimurium and improving growth performance show that this processed protein source can be considered as a nutritional effective strategy to control Salmonella contamination in broiler chicks.

Evaluation of antioxidant interactions in combined extracts of green tea (Camellia sinensis), rosemary (Rosmarinus officinalis) and oak fruit (Quercus branti).

Green tea (Camellia sinensis), rosemary (Rosmarinus officinalis) and oak fruit (Quercus branti) are of known medicinal plants used in traditional medicine. They provide substantial antioxidant activities but the possible antioxidant interaction between them has not been studied. In the present study first the bioactive compounds from these three plants were first extracted and thereafter assayed for total phenols, 2, 2-diphenyl-1- picrylhydrazyl (DPPH) radical scavenging activity, total antioxidant capacity (TAOC) and reducing power. In addition, the antioxidant properties of the extracts individually and in combinations were evaluated in soy bean oil as food system. There was a direct relation between total phenolics and antioxidant activities of extracts. Green tea and oak fruit extracts had the highest and least activity, respectively. All three kinds of interactions (synergistic, antagonistic and additive) were observed. In soy bean oil, the only effect was antagonism but even with this effect, combined extract was significantly (P < 0.05) better than butylated hydroxytoluene (BHT) and control sample. Results showed that these three natural extracts and their combination can be effectively used as a substituent of synthetic antioxidant BHT.

Study of antioxidant activity of sheep visceral protein hydrolysate: Optimization using response surface methodology.

BACKGROUND: The main objective of this experiment was optimal use of none edible protein source to increase nutritional value of production with high biological function, including antioxidant activity. METHODS: Sheep visceral (stomach and intestine) was used as substrate. Response surface methodology (RSM) was used to optimize hydrolysis conditions for preparing protein hydrolysate from the sheep visceral, using alcalase 2.4 l enzyme. The investigated factors were temperature (43-52 °C), time (90-180 min), and enzyme/substrate ratio [60-90 Anson-unit (AU)/kg protein] to achieve maximum antioxidant activity. Experiments were designed according to the central composite design. RESULTS: Each of the studied variables had a significant effect on responses (P < 0.05). Optimal conditions to achieve antioxidant activity were, temperature (48.27 °C), time (158.78), min and enzyme/substrate ratio (83.35) Anson-unit/kg protein. Under these conditions, antioxidant activity was 68.21%, R2 for model was 0.983. The values indicated the high accuracy of the model to predict the reaction conditions considering different variables. The chemical analysis of protein hydrolysate showed high protein content (83.78%) and low fat content (0.34%). CONCLUSION: Our results showed that protein hydrolysate of sheep visceral, can be used as a natural antioxidant with high nutritional value.