Assessment of polyphenolic profile and antibacterial activity of pomegranate peel (Punica granatum) flour obtained from co-product of juice extraction

Antilisterial activity of cinnamon essential oil, pomegranate extract, or strawberry tree extract against Listeria monocytogenes in slices of dry-cured ham and pork loin

Owing to concerns about the antimicrobial resistance of agents that can prevent the growth of Listeria monocytogenes in meat, researchers have investigated natural preservatives with antilisterial effects. However, in vivo application of essential oils and plant extracts usually results in reduced antimicrobial activity in meat products when compared to in vitro studies. This study aimed to evaluate the in vivo antimicrobial activity of cinnamon essential oil, pomegranate, and strawberry tree extracts in slices of dry-cured ham and pork loin against L. monocytogenes. Fragments of sterile dry-cured ham were inoculated with 100 μL cinnamon oil 0.5%, pomegranate, or strawberry crude extract. After 10 min, 100 μL of L. monocytogenes serotype 4b (104 colony-forming unit [CFU]/mL) was inoculated, and samples were incubated at 7 °C for 7 d to simulate the processing and storage temperature conditions of dry-cured meat products. L. monocytogenes was detected and quantified. Only strawberry extract presented significant differences (P < 0.05) from the control; thus, it was selected for the assay with 2% and 4% salt-treated pork loin. The strawberry tree extract significantly (P < 0.05) reduced the growth of L. monocytogenes in dry-cured ham. However, it could not reduce L. monocytogenes growth in pork loin, regardless of the salt concentration. This is the first report on the antimicrobial effect of strawberry tree leaf extract against L. monocytogenes in dry-cured ham.

Antilisterial activity of tannin rich preparations isolated from raspberry (Rubus Idaeus L.) and strawberry (Fragaria X Ananassa Duch.) fruit

The tannin rich preparations isolated from red raspberry (Rubus idaeus L.) and strawberry (Fragaria x ananassa Duch.) fruits were evaluated for their polyphenol composition and antimicrobial activity against six strains of Listeria monocytogenes, sourced from the ATCC collection. The preparations were obtained using solvent extraction with a water-acetone solution, followed by purification using Amberlite XAD 1600 resin. The resulting products, RTRP (raspberry tannin rich preparation) and STRP (strawberry tannin rich preparation), were characterized by their content of ellagitannins, proanthocyanidins, and anthocyanins. Polyphenol content was determined using HPLC-FD and UHPLC-DAD-MS with QExactive mass spectrometer. The antagonistic activity of the preparations against Listeria spp. strains was assessed using the disk diffusion method, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined by dilution techniques. The RTRP and STRP exhibited tannin contents of 74 g/100 g and 47 g/100 g, respectively. In the raspberry preparation, ellagitannins were dominant, while in the strawberry preparation, ellagitannins and proanthocyanidins were present at similar levels. In the general antagonism test at a concentration of 60 mg/mL, inhibition zones for L. monocytogenes ranged from 10.0 to 24.5 mm. The MIC values for the preparations ranged from 1.563 to 25 mg/mL, varying depending on the tested strains. Based on MIC and MBC, L. monocytogenes ATCC 19,111 was the most sensitive to the preparations, whereas ATCC 15,313 exhibited the greatest resistance. Despite their different tannin profiles, the preparations generally did not show statistically significant differences in their antilisterial activity. The results indicate that the tannin rich preparations from red raspberry and strawberry fruits exhibit moderate antilisterial activity, dependent on the sensitivity of the specific L. monocytogenes strain tested.

Phenolic Components and Biological Activity of Pomegranate

Pomegranate (Punica granatum L.) have been subject of extensive studies for its abundance of phytochemicals and numerous biological and medicinal properties. It is a fruit-bearing tree, which is widely consumed as a nutraceutical source as well as functional food for putative health benefits. The phenolic components are the characteristic bioactive constitutes of pomegranate, including hydrolysable tannins, flavonoids, and phenolic acids. The whole plant of this tree has many medicinal folkloric uses and good therapeutic effect, such as anticancer, antioxidant, antibacterial, antiviral, hypoglycemic, lipid-lowering, cardioprotection and digestive system protection. Through comprehensive search of available literature, this narrative review can provide an up-to-date overview of the current knowledge of characteristic bioactive constituents's structure and potential health benefits of Pomegranate, which can be used as reference for the future clinical and basic research, and also helpful for the development of pomegranate into functional food and nutraceuticals.

Diet Supplementation with Pomegranate Fruit Alters Distal Gut Microbiota of Healthy Female College Students

Pomegranate is a fruit that grows abundantly in the Middle East and Africa. It is rich in polyphenols, sugars, fiber, and vitamins, and has long been associated in traditional and alternative medicine with numerous health benefits, including the treatment of diarrhea and gut inflammation. We assessed how regular daily intake of fresh pomegranate can affect the distal gut microbiota of young healthy female students in Egypt, a region with abundant pomegranate production and frequent occurrence of gut dysbiosis. Interrogation of microbiota structure based on the sequencing of the 16S ribosomal RNA gene amplicons indicated that subject-to-subject variability was the main driver of microbiota community differences. Nevertheless, pomegranate consumption led to changes in the abundances of several genera including increased levels of Saccharofermentans, Enterococcus, and Prevotella. The relative counts of Dysosmobacter, Coprococcus, and Collinsella decreased after pomegranate intake. The magnitude of community structure shift after diet intervention correlated with the increase in the total polyphenol concentration measured in subjects' urine. The overall ratio of presumed beneficial-to-detrimental microbes was also improved with pomegranate addition to the diet, supporting the advantageous effects of pomegranate eating.

Carboxymethyl cellulose/shellac composite loaded with pomegranate extract and jojoba oil as anti-mycotic and anti-mycotoxigenic food packaging materials

Food commodities, including mycotoxins naturally produced from toxigenic fungi (pre- or post-harvest), are particularly vulnerable to contamination. The study intended to use unique bioactive composites loaded with antimicrobial constituents for food packaging. Three composite types are based on carboxymethyl cellulose/shellac (CMC/SH) and loaded with pomegranate extract (POE) with or without jojoba oil (JOE) at various concentrations. An enhancement was recorded for tensile strength and elongation at break and burst properties of the composites, where the results point out the amelioration of flexibility and elasticity with E9 (0.3/3 mg/mL of POE/JO). Moreover, E10 (0.3/1 of POE/JOE) content had higher phenolic and flavonoids, with significant antioxidants and the best antimicrobial and anti-mycotoxigenic activity. Six higher antimicrobial composites were chosen for corn seed coating applications in a simulated experiment of toxigenic fungal contamination, where the results recommend E10 as the best formula for packaging application. The E10 was characterized for emulsion stability, particle size, zeta potential, pH, PDI, and acidity that were recorded at 88.16 ± 2.87%, 54.81 nm, 38.74 mV, 6.34 ± 0.54, 31.12 ± 1.02, and 6.02 ± 0.34 mg/L, respectively. The in-silico study revealed that ellagic acid and hesperidin in POE extract, erucic and oleic acids in JOE, and shellac had the highest binding free energies against the vital enzymes involved in bactericidal/bacteriostatic effects and the aflatoxin bio synthetic mechanism.

Effects of storage and processing on the residual distribution and behavior of five preservatives and their metabolites in pomegranate

Pomegranate are often treated with preservatives during storage. This study investigated the effects of storage and food processing on the residual behavior of the five commonly used preservatives (prochloraz, thiophanate-methyl, pyrimethanil, imazalil, and difenoconazole) and their metabolites in pomegranate and its products. The LOQs for all target compounds were 0.001 mg kg-1. The residue levels of five preservatives in the calyx was highest, followed by the peel, stalk, septum, umbilicus, and seed. For the migration ability, the five preservatives from pomegranate peel to seed was negatively correlated with their octanol/water partition coefficients. The processing factors of each procedures of juice, wine, vinegar, and pectin processing were <1. Nevertheless, the PF values in drying peel during the overall process ranged from 1.26 to 4.09. Hence, it is worth noting that consumption of pomegranate essential oil and drying peel may pose a potential risk to the health of consumers.

Hepatoprotective Effect of Ethanolic Pomegranate Peel Extract Against Levofloxacin via Suppression of Oxidative Stress, Proinflammation, and Apoptosis in Male Rats

One of the fluoroquinolone antibiotics, levofloxacin (LEV), is used to treat a variety of illnesses leading to oxidative stress and cellular damage. Peel from Punica granatum is a waste product abundant in phytochemicals with various biological activities. This study aimed to evaluate P. granatum peel extract's (PGPE) potential to mitigate oxidative stress, inflammation, apoptosis, and liver damage caused by LEV. There were four groups of rats: control, PGPE, LEV, and PGPE + LEV, respectively, and they were orally administered their daily treatments for 2 weeks. Results revealed that PGPE has a large number of phytochemical components with high antioxidant activity. PGPE intake alone enhanced the antioxidant status and decreased oxidative stress. On the other hand, pretreatment of the LEV group with PGPE restored oxidative stress, antioxidant enzymes, glutathione content, liver function biomarkers, and hematological parameters. Also, normalization of gene expressions (cyclooxygenase-2, transforming growth factor-beta1, caspase-3, heme oxygenase-1, B cell lymphoma-2, interleukin [IL]-10, and IL-1) and improvement in liver architecture, and immunohistochemical alpha-smooth muscle actin, were seen in comparison to the LEV group. Conclusively, PGPE exhibits strong anti-inflammatory, antiapoptotic, and antioxidant properties that shield rat liver from the damaging effects of LEV and offer a fresh viewpoint on the application of fruit waste products.

Comparative Study of Callistemon citrinus (Bottlebrush) and Punica granatum (Pomegranate) Extracts for Sustainable Synthesis of Silver Nanoparticles and Their Oral Antimicrobial Efficacy

A comparative study was applied to investigate the potential of Callistemon citrinus (bottlebrush) flower extract (BBE) and Punica granatum (pomegranate) peel extracts (PPE) for the sustainable synthesis of the silver nanoparticles, Ag-BBE and Ag-PPE, respectively. The synthesis process of Ag NPs using the selected extracts was applied under optimized conditions. Hence, the effect of the selected plant's type on the different characteristics of the synthesized green Ag NPs was investigated. The UV-Vis spectroscopy revealed the presence of the characteristic silver peaks at 419 and 433 nm of the Ag-BBE and Ag-PPE, respectively. The XRD spectra reported the fcc phase formation of Ag NPs. The TEM results highlighted the morphological features of the synthesized Ag NPs. with a size range of 20-70 nm, and with 10-30 nm for Ag-BBE and Ag-PPE, correspondingly. The Raman spectra revealed characteristic silver bands in the Ag-PPE and reflected some bands related to the natural extract in the Ag-BBE sample. The antimicrobial activity and statistical analysis investigation were conducted against four selected oral pathogens (Staphylococcus aureus (SA), Candida albicans (CA), Staphylococcus epidermidis (S. epi), and Enterococcus faecalis (EF)). Both tested extracts, BBE, and PPE, revealed potential effectivity as reducing and capping agents for Ag NP green synthesis. However, the synthesized NPs demonstrated different features, depending on the used extract, reflecting the influence of the plant's biomolecules on the nanoparticles' properties.

Recovery of Ellagic Acid from Pomegranate Peels with the Aid of Ultrasound-Assisted Alkaline Hydrolysis

The pomegranate processing industry generates worldwide enormous amounts of by-products, such as pomegranate peels (PPs), which constitute a rich source of phenolic compounds. In this view, PPs could be exploited as a sustainable source of ellagic acid, which is a compound that possesses various biological actions. The present study aimed at the liberation of ellagic acid from its bound forms via ultrasound-assisted alkaline hydrolysis, which was optimized using response surface methodology. The effects of duration of sonication, solvent:solid ratio, and NaOH concentration on total phenol content (TPC), antioxidant activity, and punicalagin and ellagic acid content were investigated. Using the optimum hydrolysis conditions (i.e., 32 min, 1:48 v/w, 1.5 mol/L NaOH), the experimental responses were found to be TCP: 4230 ± 190 mg GAE/100 g dry PPs; AABTS: 32,398 ± 1817 µmol Trolox/100 g dry PPs; ACUPRAC: 29,816 ± 1955 µmol Trolox/100 g dry PPs; 59 ± 3 mg punicalagin/100 g dry PPs; and 1457 ± 71 mg ellagic acid/100 g dry PPs. LC-QTOF-MS and GC-MS analysis of the obtained PP extract revealed the presence of various phenolic compounds (e.g., ellagic acid), organic acids (e.g., citric acid), sugars (e.g., fructose) and amino acids (e.g., glycine). The proposed methodology could be of use for food, pharmaceutical, and cosmetics applications, thus reinforcing local economies.

Cistus incanus: a natural source of antimicrobial metabolites

The discovery of natural molecules with antimicrobial properties has become an urgent need for the global treatment of bacterium and virus infections. Cistus incanus, a Mediterranean shrub species, represents a valuable source of phytochemicals with an interesting wide-spectrum antimicrobial potential. In this study, we analysed the spectrum of molecules composing a commercial hydroalcoholic extract of C. incanus finding ellagitannins as the most abundant. The effect of the extract and its main constituents (gallic acid, ellagic acid and punicalin) was assessed as co-treatment during viral (HSV-1, HCoV-229E, SARS-CoV-2) and bacterial infection (Staphylococcus aureus and Escherichia coli) of cells and as pre-treatment before virus infections. The results indicated a remarkable antiviral activity of punicalin against SARS-CoV-2 by pre-treating both the viral and the host cells, and a major sensitivity of S. aureus to the C. incanus extract compared to E. coli. The present study highlights broad antimicrobial potential of C. incanus extract.

Punicalagin, a pomegranate polyphenol sensitizes the activity of antibiotics against three MDR pathogens of the Enterobacteriaceae

BACKGROUND

Multidrug resistance (MDR) in the family Enterobacteriaceae is a perniciously increasing threat to global health security. The discovery of new antimicrobials having the reversing drug resistance potential may contribute to augment and revive the antibiotic arsenal in hand. This study aimed to explore the anti-Enterobacteriaceae capability of bioactive polyphenols from Punica granatum (P. granatum) and their co-action with antibiotics against clinical isolates of Enterobacteriaceae predominantly prevalent in South Asian countries.

METHODS

The Kandhari P. granatum (Pakistani origin) extracts were tested for anti-Enterobacteriaceae activity by agar well diffusion assay against MDR Salmonella enterica serovar Typhi, serovar Typhimurium and Escherichia coli. Predominant compounds of active extract were determined by mass spectrometry and screened for bioactivity by agar well diffusion and minimum inhibitory concentration (MIC) assay. The active punicalagin was further evaluated at sub-inhibitory concentrations (SICs) for coactivity with nine conventional antimicrobials using a disc diffusion assay followed by time-kill experiments that proceeded with SICs of punicalagin and antimicrobials.

RESULTS

Among all P. granatum crude extracts, pomegranate peel methanol extract showed the largest inhibition zones of 25, 22 and 19 mm, and the MICs as 3.9, 7.8 and 7.8 mg/mL for S. typhi, S. typhimurium and E. coli, respectively. Punicalagin and ellagic acid were determined as predominant compounds by mass spectrometry. In plate assay, punicalagin (10 mg/mL) was active with hazy inhibition zones of 17, 14, and 13 mm against S. typhi, S. typhimurium and E. coli, respectively. However, in broth dilution assay punicalagin showed no MIC up to 10 mg/mL. The SICs 30 μg, 100 μg, and 500 μg of punicalagin combined with antimicrobials i.e., aminoglycoside, β-lactam, and fluoroquinolone act in synergy against MDR strains with % increase in inhibition zone values varying from 3.4 ± 2.7% to 73.8 ± 8.4%. In time-kill curves, a significant decrease in cell density was observed with the SICs of antimicrobials/punicalagin (0.03-60 μg/mL/30, 100, 500 μg/mL of punicalagin) combinations.

CONCLUSIONS

The P. granatum peel methanol extract exhibited antimicrobial activity against MDR Enterobacteriaceae pathogens. Punicalagin, the bacteriostatic flavonoid act as a concentration-dependent sensitizing agent for antimicrobials against Enterobacteriaceae. Our findings for the therapeutic punicalagin-antimicrobial combination prompt further evaluation of punicalagin as a potent activator for drugs, which otherwise remain less or inactive against MDR strains.

Phytochemical profile, nutritional composition of pomegranate peel and peel extract as a potential source of nutraceutical: A comprehensive review

The current study focuses on Punica granatum L. (pomegranate) peel and peel extract and their use as functional foods, food additives, or physiologically active constituents in nutraceutical formulations. The pomegranate peel extract is a good source of bioactive substances needed for the biological activity of the fruit, including phenolic acids, minerals, flavonoids (anthocyanins), and hydrolyzable tannins (gallic acid). The macromolecules found in pomegranate peel and peel extract have been recommended as substitutes for synthetic nutraceuticals, food additives, and chemo-preventive agents because of their well-known ethno-medical significance and chemical properties. Moreover, considering the promises for both their health-promoting activities and chemical properties, the dietary and nutraceutical significance of pomegranate peel and pomegranate peel extract appears to be underestimated. The present review article details their nutritional composition, phytochemical profile, food applications, nutraceutical action, and health benefits.

Biosynthesis and characterization of silver nanoparticles from Punica granatum (pomegranate) peel waste and its application to inhibit foodborne pathogens

Polyphenolics have been predicted to effectively develop antimicrobial agents for the food industry as food additives and promote human health. This study aims to synthesize pomegranate peel extract (PPE) with silver nanoparticles (AgNPs) against eight foodborne pathogens. Multispectroscopic analysis of UV-vis spectroscopy, Zeta potential, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis were used to characterize the interaction between PPE and AgNPs. Eight foodborne pathogenic strains (six bacterial and two fungal strains) Bacillus subtilis ATCC 6633, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 8379, Klebsiella pneumoniae ATCC 00607, Salmonella typhi DSM 17058, Shigella sonnei DSM 5570, Aspergillus flavus ATCC 9643, and Rhizopus oryzae ATCC 96382 were used to test the inhibitory potential of PPW-AgNPs. The reaction colour of PPE-AgNPs from yellow to brown indicated that the nanoparticles were successfully formed. The UV absorption of PPE-AgNPs was detected at 440 nm of 0.9 SPR. SEM image of PPE-AgNPs exhibited spherical shapes with a zeta potential of - 20.1 mV. PPE-AgNPs showed high antimicrobial activity against all tested strains. The highest inhibition activity of PPE-AgNPs was recorded for the B. subtilis strain followed by K. pneumonia, while the highest resistance was noticed for R. oryzae. The components of pomegranate peel were analyzed using gas chromatography-mass spectrometry (GC-MS). The major constituents of pomegranate peel is phenol (51.1%), followed by Isocitronellol (19.41%) and 1-Propanol, 2-(2-hydroxypropyl)- (16.05%). PPE is key in the simple, eco-friendly green synthesis of extracellular stable AgNPs as an alternative source for harmful chemical disinfectants.

Comparative Study of Cytotoxicity and Antioxidant, Anti-Aging and Antibacterial Properties of Unfermented and Fermented Extract of Cornus mas L

Due to the high demand for products that can help treat various skin conditions, the interest in plant extracts, which are a valuable source of phytochemicals, is constantly growing. In this work, the properties of extracts and ferments from Cornus mas L. and their potential use in cosmetic products were compared. For this purpose, their composition, antioxidant properties and cytotoxicity against skin cells, keratinocytes and fibroblasts were assessed in vitro. In addition, the ability to inhibit the activity of collagenase and elastase was compared, which enabled the assessment of their potential to inhibit skin aging. Microbiological analyses carried out on different bacterial strains were made in order to compare their antibacterial properties. The conducted analyses showed that both dogwood extract and ferment have antioxidant and anti-aging properties. In addition, they can have a positive effect on the viability of keratinocytes and fibroblasts and inhibit the proliferation of various pathogenic bacteria, which indicates their great potential as ingredients in skin care preparations. The stronger activity of the ferment compared to the extract indicates the legitimacy of carrying out the fermentation process of plant raw materials using kombucha in order to obtain valuable products for the cosmetics industry.

Alginate Nanoencapsulated Synbiotic Composite of Pomegranate Peel Phytogenics and Multi-Probiotic Species as a Potential Feed Additive: Physicochemical, Antioxidant, and Antimicrobial Activities

A synbiotic composed of alginate nanoencapsulated prebiotic (pomegranate peel phytogenics) and multi-species probiotics (Lactococcus lactis, Lactobacillus plantarum, Lactobacillus paracasei, and Saccharomyces cerevisiae) has been developed as a potential eco-friendly alternative to antibiotics. The physicochemical properties of the encapsulated synbiotic were evaluated, and its gastric and storage tolerance, as well as its antioxidant and antimicrobial activity, were tested and compared to that of the non-encapsulated synbiotic (free synbiotic). The results showed that the prebiotic pomegranate peel ethanolic extract contained seven phenolic compounds, with cinnamic being the most abundant (13.26 µL/mL). Sodium alginate-CaCl2 nanocapsules were effective in encapsulating 84.06 ± 1.5% of the prebiotic's phenolic compounds and 98.85 ± 0.57% of the probiotics. The particle size of the alginate-CaCl2 nanoencapsulated synbiotic was 544.5 nm, and the polydispersity index and zeta potential values were 0.593 and -12.3 mV, respectively. Thermogravimetric analysis showed that the alginate-CaCl2 nanoencapsulated synbiotic had high thermal stability at high temperatures, with only 2.31% of its weight being lost within the temperature range of 70-100 °C. The count of viable probiotics in the nanoencapsulated synbiotic was significantly higher than that in the free synbiotic after exposure to gastric acidity and storage for six months at room temperature. The percent inhibition values of the nanoencapsulated synbiotic and ascorbic acid (as a standard antioxidant) were comparable and significantly greater than those of the free synbiotic. The half-maximal inhibitory concentrations (IC50) of the nanoencapsulated synbiotic and ascorbic acid were significantly lower than those of the free synbiotic (3.96 ± 0.42 µg/mL and 4.08 ± 0.79 µg/mL for nanoencapsulated synbiotic and ascorbic acid, respectively, vs. 65.75 ± 2.14 µg/mL for free synbiotic). The nanoencapsulated synbiotic showed the highest significant antimicrobial activity against Escherichia coli (ATCC 8739). Both the nanoencapsulated and free synbiotics showed antimicrobial activity against Staphylococcus aureus (ATCC 6538), similar to that of gentamicin, although the nanoencapsulated synbiotic showed significantly higher inhibition activity compared to the free synbiotic. The nanoencapsulated synbiotic showed antimicrobial activity comparable to gentamicin against Pseudomonas aeruginosa (ATCC 90274), whereas the free synbiotic showed the least antimicrobial activity (p < 0.05). Both synbiotics showed significantly higher antimicrobial activity against Salmonella typhi (ATCC 6539) than gentamicin. Both synbiotics showed antifungal activity against Aspergillus niger and Aspergillus flavus, with a stronger effect observed for the nanoencapsulated synbiotic. However, the activity of both synbiotics was significantly lower than that of fluconazole (an antifungal drug).

Pomegranate: A Source of Multifunctional Bioactive Compounds Potentially Beneficial in Alzheimer's Disease

Pomegranate fruit (PF) is a fruit rich in nutraceuticals. Nonedible parts of the fruit, especially peels, contain high amounts of bioactive components that have been largely used in traditional medicine, such as the Chinese, Unani, and Ayurvedic ones, for treating several diseases. Polyphenols such as anthocyanins, tannins, flavonoids, phenolic acids, and lignans are the major bioactive molecules present in PF. Therefore, PF is considered a source of natural multifunctional agents that exert simultaneously antioxidant, anti-inflammatory, antitumor, antidiabetic, cardiovascular, and neuroprotective activities. Recently, several studies have reported that the nutraceuticals contained in PF (seed, peel, and juice) have a potential beneficial role in Alzheimer's disease (AD). Research suggests that the neuroprotective effect of PF is mostly due to its potent antioxidant and anti-inflammatory activities which contribute to attenuate the neuroinflammation associated with AD. Despite the numerous works conducted on PF, to date the mechanism by which PF acts in combatting AD is not completely known. Here, we summarize all the recent findings (in vitro and in vivo studies) related to the positive effects that PF and its bioactive components can have in the neurodegeneration processes occurring during AD. Moreover, considering the high biotransformation characteristics of the nutraceuticals present in PF, we propose to consider the chemical structure of its active metabolites as a source of inspiration to design new molecules with the same beneficial effects but less prone to be affected by the metabolic degradation process.

Evaluation of Effects of Spray Drying Conditions on Physicochemical Properties of Pomegranate Juice Powder Enriched with Pomegranate Peel Phenolic Compounds: Modeling and Optimization by RSM

In this study, the effects of pomegranate peel extract concentration (2.5-10%), drying temperature (160-190 °C), and feed flow rate (0.6-1 mL/s) on the properties of pomegranate juice powder enriched with pomegranate peel phenolic compounds and produced by spray drying were investigated. The moisture content, water activity (a_w), solubility, water absorption capacity (WAC), hygroscopicity, dissolution time, total phenolic content (TPC), Carr index (CI), Hausner ratio (HR), and brightness (L*) of the samples were evaluated, and the optimal powder production conditions were obtained using response surface methodology (RSM). The results showed that the optimal conditions were found to be the phenolic extract concentration of 10%, the drying temperature of 189.9 °C, and the feed flow rate of 0.63 mL/s, considering the minimization of the moisture content, a_w, hygroscopicity, dissolution time, CI, HR, and L*, as well as the maximization of solubility, WAC, and TPC. The effect of the phenolic extract concentration was very significant (p < 0.01) on the WAC, hygroscopicity, dissolution time, TPC, CI, HR, and L* of the powder. Moreover, the effect of the drying temperature was very significant (p < 0.01) on the a_w, hygroscopicity, dissolution time, CI, and HR of the powder and significant (p < 0.05) on its moisture content. The effect of the feed flow rate was very significant (p < 0.01) on the solubility, hygroscopicity, and dissolution time of the powder and significant (p < 0.05) on its moisture content. Therefore, we found that the spray drying conditions, such as high temperature, did not negatively affect the content of phenolic compounds in pomegranate powder, and the physical properties of the resulting powder were acceptable. Thus, pomegranate powder enriched with phenolic compounds can be used as a food additive or as a dietary supplement for medicinal use.

Enhanced Chromium (VI) Adsorption onto Waste Pomegranate-Peel-Derived Biochar for Wastewater Treatment: Performance and Mechanism

Surface chemical modification allows for the rational construction of biochar with desirable structures and functionalities for environment purification. Fruit-peel-derived adsorbing material has been well studied in the adsorption of heavy-metal removal due to its abundance and non-toxicity, but its precise mechanism in removing chromium-containing pollutants remains unclear. Herein, we explored the potential application of engineered biochar prepared from fruit waste via chemical modification to remove chromium (Cr) from an aqueous solution. By synthesizing two types of agricultural residue-derived adsorbents, including pomegranate peel adsorbent (PG) and its modified product, pomegranate-peel-derived biochar (PG-B), via chemical and thermal decomposition methods, we elucidated the adsorption property of Cr(VI) on the studied materials and identified the cation retention mechanism of the adsorption process. Batch experiments and varied characterizations demonstrated that superior activity was exhibited in PG-B, which can contribute to the porous surfaces caused by pyrolysis and effective active sites resulting from alkalization. The highest Cr(VI) adsorption capacity is obtained at pH 4, a dosage of 6.25 g L^-1, and a contact time of 30 min. The maximum adsorption efficiency of 90.50% in a short period (30 min) was obtained on PG-B, while PG reached a removal performance of 78.01% at 60 min. The results from kinetic and isotherm models suggested that monolayer chemisorption dominated the adsorption process. The Langmuir maximum adsorption capacity is 16.23 mg g^-1. This study shortened the adsorption equilibrium time of pomegranate-based biosorbents and presents positive significance in designing and optimizing waste fruit-peel-derived adsorption materials for water purification.

Physicochemical and thermal characterization, and evaluation of a bacterial cellulose/Barhang gum-based dressing for wound healing

The gram-negative bacterium of Gluconacetobacter xylinum is widely used to produce high-quality cellulose in the form of complex strips in microfiber bundles on a commercial scale. In this study, the film-forming potential of bacterial cellulose in combination with polyvinyl alcohol (PVA, 5 % w/v) and Barhang seed gum (BSG, 0.5 % w/v) loaded with summer savory (Satureja hortensis L.) essential oil (SSEO) to prepare a new wound dressing was investigated. The X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), field emission-scanning electron microscopy (FE-SEM), and thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) surface area, in-vitro antibacterial, and in-vivo wound healing activities were performed to assess the structure, morphology, stability, and bioactivity of biocomposite films. Results showed that the SSEO incorporation into the polymeric matrix yielded smooth and transparent composite film with excellent thermal resistance. A significantly robust antibacterial activity against gram-negative bacteria by the bio-film was found. The healing process on mice models revealed that the SSEO-loaded composite film had a promising potential for wound healing associated with improved collagen deposition and reduced inflammatory response.

Chitosan-based Schiff base-metal (Fe, Cu, and Zn) complexes mitigate the negative consequences of drought stress on pomegranate fruits

Drought is one of the major environmental stresses that impairs fruit productivity and quality. The proper management of minerals can, however, assist plant to maintain their growth even under drought incidents, and is considered one of the encouraging approaches to refine the drought tolerance of plants. The beneficial effects of chitosan (CH)-based Schiff base-metal complexes (e.g., CH-Fe, CH-Cu and CH-Zn) in reducing the harmful impacts of different levels of drought stress on the growth and productivity of 'Malase Saveh' pomegranate cultivar were examined. All CH-metal complexes displayed favorable effects on the yield- and growth-related attributes of pomegranate trees cultivated under well-watered and different drought situations, with the best effects were observed with CH-Fe application. Specifically, leaves of CH-Fe-treated pomegranate plants showed higher concentrations of photosynthetic pigments [chlorophyll a (Chl a), Chl b, Chl a+b, and carotenoids by 28.0, 29.5, 28.6 and 85.7%, respectively] and microelements (Fe by 27.3%), along with increased levels of superoxide dismutase (by 35.3%) and ascorbate peroxidase (by 56.0%) enzymatic activities relative to those of CH-Fe-non-treated pomegranate plants under intense drought stress. CH-Fe-treated drought-stressed pomegranate leaves showed high increment of abscisic acid (by 25.1%) and indole-3-acetic acid (by 40.5%) relative to CH-Fe-non-treated pomegranates. The increased contents of total phenolics, ascorbic acid, total anthocyanins, and titratable acidity (by 24.3, 25.8, 9.3 and 30.9%, respectively) in the fruits of CH-Fe-treated drought-stressed pomegranates indicated the advantageousness of CH-Fe on the enhancement of fruit nutritional qualities. Collectively, our results prove the explicit functions of these complexes, particularly CH-Fe, in the control of drought-induced negative effects on pomegranate trees grown in semi-arid and dry areas.

Potential of phenolic compounds from pomegranate (Punica granatum L.) by-product with significant antioxidant and therapeutic effects: A narrative review

The wealth of epidemiological evidence in the scientific world underscores the possibility that a plant-based diet can reduce the prevalence of common diseases such as diabetes, cardiovascular disease, cancer, and stroke. The therapeutic effects of plant sources are partly explained by phenolic secondary metabolites or polyphenolic compounds. Therefore, polyphenolic compounds, which are widely distributed in plants, are of great interest for the development of effective specific drugs with antioxidant and anti-inflammatory effects. Moreover, polyphenol compounds have no harmful effects due to their natural biocompatibility and safety. Numerous studies have highlighted the potential of some industrial food wastes from plant material processing, including apple peels and mashed potatoes, grape skins, tomato and carrot peels, pomegranate peels and seeds, and many others. These byproducts are considered low-cost sources of natural biological compounds, including antioxidants, which have beneficial effects on human health. The polyphenol complex of pomegranate peel (Punica granatum L.), which makes up half of the pomegranate fruit, has more pronounced antioxidant and anti-inflammatory properties than other parts. And the most important active components of pomegranate peel, which are found only in this plant, are punicalagin, followed by ellagic acid and gallic acid. It is known that these polyphenolic compounds of pomegranate peel have the most pronounced therapeutic effect. Several studies have shown the protective effect of ellagic acid, punicalagin, against oxidative stress damage caused by free radicals. The potential of pomegranate peel as an antioxidant and therapeutic component in various biological systems is high, according to scientific sources. However, despite extensive research in recent years, a review of sources has shown that there is insufficient evidence to support the therapeutic effects of polyphenolic compounds from pomegranate peels. The role of pomegranate peel polyphenolic compounds, including flavonoids, as antioxidants in various biological systems also requires further research. Of particular importance are the mechanisms by which antioxidants influence the cellular response against oxidative stress. The purpose of this review was to report our current knowledge of plant polyphenolic compounds and their classification, and to evaluate the potential of phenolic compounds from pomegranate peels with significant antioxidant and therapeutic effects.

The Therapeutic Alliance between Pomegranate and Health Emphasizing on Anticancer Properties

Pomegranate is a fruit bearing-plant that is well known for its medicinal properties. Pomegranate is a good source of phenolic acids, tannins, and flavonoids. Pomegranate juice and by-products have attracted the scientific interest due to their potential health benefits. Currently, the medical community has showed great interest in exploiting pomegranate potential as a protective agent against several human diseases including cancer. This is demonstrated by the fact that there are more than 800 reports in the literature reporting pomegranate's anticancer properties. This review is an update on the research outcomes of pomegranate's potential against different types of human diseases, emphasizing on cancer. In addition, perspectives of potential applications of pomegranate, as a natural additive aiming to improve the quality of animal products, are discussed.

Effect of Gastrointestinal Digestion on the Bioaccessibility of Phenolic Compounds and Antioxidant Activity of Fermented Aloe vera Juices

Plant-based beverages are enriched by the fermentation process. However, their biocompounds are transformed during gastrointestinal digestion, improving their bioaccessibility, which is of primary importance when considering the associated health benefits. This study aimed to evaluate the effect of in vitro gastrointestinal digestion on phenolic compound bioaccessibility and antioxidant activity of novel Aloe vera juices fermented by probiotic Enterococcus faecium and Lactococcus lactis. Aloe vera juices were digested using the standardized static INFOGEST protocol. During digestion, phenolic compounds and antioxidant activity (DPPH, ABTS, and FRAP) were accessed. The digestion process was seen to significantly increase the total phenolic content of the fermented Aloe vera juices. The fermentation of Aloe vera increased the bioaccessibility of juice biocompounds, particularly for kaempferol, ellagic acid, resveratrol, hesperidin, ferulic acid, and aloin. The phenolics released during digestion were able to reduce the oxidative radicals assessed by ABTS and FRAP tests, increasing the antioxidant action in the intestine, where they are absorbed. The fermentation of Aloe vera by probiotics is an excellent process to increase the bioavailability of beverages, resulting in natural added-value functional products.

Potential of nanochitosan coating combined with walnut green husk to improve the preservation of rainbow trout (Oncorhynchus mykiss) during refrigerated storage

The present study evaluated the potential of nanochitosan coating enriched with ethanol-water extract of the walnut green husk (WGHE) on spoilage and rancidity of rainbow trout (Oncorhynchus mykiss) during six-day refrigerated storage. Hence, we have considered fresh trout fillets without any treatment as control (C), immersed in 2% solution of chitosan nanoparticles (CN), combination with 1.5% and 3% WGHE with nanochitosan coating (CN + WGHE 1.5 and CN + WGHE3), for physicochemical, microbial and sensorial assays. The highest levels and total volatile nitrogen were observed after day 6 in C, while the lowest was found in CN + WGHE3 groups. Thiobarbituric acid reactive substance (TBARS) and peroxide value of untreated fillets on day 6 of the study were significantly higher than NC + WGHE3 with 0.08 mg/g and 3.27 mEq/kg, respectively. The total microbial population was: C ˃ CN ˃ CN + WGHE 1.5 > CN + WGHE3, which expresses the effect of the extract on the total microbial population. Overall, the combination of WGHE with CN increased the extract's efficiency in reducing peroxide value, TBARS, and total volatile nitrogen and delayed the pH increase, improving the overall acceptability of rainbow trout fillets stored in refrigerated conditions.

Extraction of Polyphenols and Valorization of Fibers from Istrian-Grown Pomegranate (Punica granatum L.)

Pomegranate fruit is an ancient fruit that is used not only because of its deep-red color and tasty arils but also due to the health benefits of its extracts. Pomegranate is a valuable source of bioactive compounds, including colorful anthocyanins and other polyphenols. The main objective of the present study was to gain comprehensive knowledge of the phenolic composition and antioxidative activity of a new pomegranate cultivar, grown in Northwest Istria, a part of the North Adriatic coastal area. Various parts of the pomegranate fruit parts were extracted in 70% ethanol or water. Total phenolic content and antioxidative capacity were respectively determined with Folin–Ciocalteu reagent and ABTS radical. Phenolics were examined and analyzed with TLC, LC-MS, and HPLC. Pomegranate juice was prepared from red arils and after thermal treatment, the stability of anthocyanins was monitored for several months to understand the effect of storage. The highest total phenolics were determined in ethanol pomegranate peel extracts (30.5 ± 0.6 mg GAE/g DM), and water peel extracts exhibited the highest antioxidative activity (128 ± 2 µg TE/g DM). After five months of storage of thermally treated pomegranate juice, 50–60 percentage points increase in anthocyanin degradation was observed. Pomegranate peel was further tested as a sustainable inedible food source for papermaking. Due to the low content of cellulose and the high percentage of extractives, as well as a distinguished texture and appearance, the paper made from pomegranate peel is best suited for the production of specialty papers, making it particularly interesting for bioactives recovery, followed by material restructuring.

Effect of Antimicrobial and Antioxidant Rich Pomegranate Peel Based Edible Coatings on Quality and Functional Properties of Chicken Nuggets

The current study evaluated the effect of pomegranate peel-based edible coating on chicken nuggets in order to develop a functional and safe product, high in nutritional value. For this purpose, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and total phenolic content (TPC) assays were performed to check the potential antioxidant activity of chicken nuggets; microbial control, including total aerobic count and coliforms population, was performed for quality and safety purposes; and thiobarbituric acid reactive substances (TBARS) and peroxide value (POV) were performed to determine the oxidative stability of chicken nuggets. Different treatments were applied at different storage periods (0th, 7th, 14th and 21st day). The higher value of total aerobic count (5.09 ± 0.05 log CFU/g) and coliforms (3.91 ± 0.06 log CFU/g) were obtained for the uncoated samples, while the lower population was enumerated in the combination of sodium alginate (SA) and pomegranate peel powder (PPP). However, DPPH (64.65 ± 2.15%) and TPC (135.66 ± 3.07 GAE/100 g) values were higher in the coated chicken nuggets (SA (1.5%) and PPP (1.5%)) and lowest in the control samples. The higher value of TBARS (1.62 ± 0.03 MDA/kg) and POV (0.92 ± 0.03 meq peroxide/kg) were observed in the uncoated chicken nuggets. In the Hunter color system, L*, a*, and b* peak values were determined in the coated chicken nuggets with SA (1.5%) + PPP (1.5%) at the 21st day of storage. The uncoated chicken nuggets had different sensory characteristics (appearance, color, taste, texture, and overall acceptability) compared to the coated samples. Conclusively, coating based on the combination of SA (1.5%) and PPP (1.5%) increased the quality, safety, and nutritional properties of chicken nuggets.

Antimicrobial Properties of Chilean Native Plants: Future Aspects in Their Application in the Food Industry

Food contamination with microorganisms is responsible for food spoilage, deterioration and change of organoleptic properties of foods. Besides, the growth of pathogenic microorganisms can provoke serious health problems if food is consumed. Innovative packaging, such as active packaging, is increasing rapidly in the food industry, especially in applying antimicrobials into delivery systems, such as sachets. Chile is a relevant hotspot for biodiversity conservation and a source of unique bio-resources with antimicrobial potential. In this review, fifteen native plants with antimicrobial properties are described. Their antimicrobial effects include an effect against human pathogens. Considering the emergence of antimicrobial resistance, searching for new antimicrobials to design new strategies for food pathogen control is necessary. Chilean flora is a promising source of antimicrobials to be used in active packaging. However, further studies are required to advance from laboratory tests of their antimicrobial effects to their possible effects and uses in active films.

Pomegranate (Punica granatum L.) Peel Flour as Functional Ingredient for Chorizo: Effect Physicochemical and Sensory Characteristics of Functional Meat Products

Functional meat products are necessary to improve the health of consumers without detrimental effects on high biological value protein consumption. The incorporation of natural antioxidants and dietary fibre from agro-industrial coproducts is a good alternative to improve the nutritional characteristics of meat products. Pomegranate peel flour was employed as a functional ingredient to replace part of the fat, in a raw meat product like chorizo, determining changes in instrumental colour and texture, sensory acceptation, and neophobia. Pomegranate peel flour presented high content of polyphenols with considerable antioxidant activity, and high content of dietary fibre as well. Fibre retained moisture, decreasing water activity of the chorizos, decreasing pH during storage. Pomegranate peel flour increased the colour tone of the chorizos and decreased colour intensity, with a tough but easy to crumble texture. Sensory acceptation of chorizos with pomegranate peel flour was higher than control, although taste and texture were scored lower than the control sample. Results show that incorporation of pomegranate peel flour decreased Aw and pH, besides increased the samples luminosity and tone. Chorizo with pomegranate peel flour were harder than control. Nonetheless, as a functional ingredient improved health benefits with a positive consumers’ acceptance, non-neophobic, particularly in older consumers (40-50 years old). Pomegranate peel flour is a viable ingredient in the formulation of functional meat products.

Phenolic Compounds and Bioactivities from Pomegranate (Punica granatum L.) Peels

Pomegranate peels, which are normally processed as the main byproduct of pomegranate juice production, are worthy of being researched and utilized for the aim of economic and environmental benefits. In a phytochemical investigation of the peels of Punica granatum L., 10 phenolic compounds containing a common hexahydroxy diphenol moiety were isolated. Three of them were identified for the first time and named as pomegranatins A-C, and from the other seven known ones, two of them were obtained from pomegranate peels for the first time. Their structures were determined via extensive spectroscopic analysis. Besides, for the sake of preliminarily comprehending their biological activities, in vitro antimicrobial, antioxidant, as well as antitumor assays were detected. In the DPPH antioxidant assay, six compounds presented significant free radical scavenging ability. Two compounds exhibited moderate antimicrobial activities against Candida albicans; one compound could inhibit the proliferation of both C. albicans and Escherichia coli within limits. Four compounds possessed weak antitumor activity toward the Hela cell line without taking into account the bioavailability of ellagitannins. Overall, these results provided further information on the structural diversity of bioactive compounds present in pomegranate peels, as well as on their biological activities.

Effect of Extraction Method on the Bioactive Composition, Antimicrobial Activity and Phytotoxicity of Pomegranate By-Products

Pomegranate by-products can be an asset to the food industry due to the richness in bioactive and antimicrobial compounds. This work studied the influence of conventional solvent and sonication-assisted extraction methods on the bioactive profile, antimicrobial properties, and phytotoxicity effect of the peels and seeds extracts from Acco, Big Full, and Wonderful pomegranate cultivars. The bioactive composition of the extracts was evaluated for the content of total phenolics, total flavonoids, and antioxidant activity (expressed as the half-maximal inhibitory concentration—IC₅₀) by spectrophotometric methods, while the tannins were determined by titration and the anthocyanins were estimated by the pH-differential method. For the evaluation of the antimicrobial activity, the disk diffusion method of Kirby-Bauer was adapted through inhibition halos against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, and Yarrowia lipolytica. The extracts’ phytotoxicity was evaluated in vitro on garden-cress seeds. Extracts from conventional extraction were richer in total phenolics, expressed as gallic acid equivalents (0.16–0.73 mg GAE/mg extract), while those from sonication-assisted extraction had higher contents of total flavonoids, expressed as catechin equivalents (0.019–0.068 mg CATE/mg extract); anthocyanins, expressed as cyanidin-3-glucoside (0.06–0.60 µg C3G/mg, dry basis); and antioxidant activity (IC₅₀, 0.01–0.20 mg/mL). All extracts were more effective against Gram-positive bacteria and yeasts than Gram-negative bacteria. In general, the sonication-assisted extracts led to higher inhibition halos (8.7 to 11.4 mm). All extracts presented phytotoxicity against garden-cress seeds in the tested concentrations. Only the lowest concentration (0.003 mg/mL) enabled the germination of seeds and root growth, and the sonication-assisted extracts showed the highest Munoo-Liisa vitality index (51.3%). Overall, sonication-assisted extraction obtained extracts with greater bioactive and antimicrobial potential and less phytotoxicity.

Antimicrobial activity of essential oils and natural plant extracts against Listeria monocytogenes in a dry-cured ham-based model

BACKGROUND

Listeria monocytogenes is a widespread common contaminant in food production facilities during preparation, storage, and distribution, and minimally processed ready-to-eat products are considered at high risk of contamination by this bacterium. Increased antibiotic resistance has led researchers to search for plant-based natural alternatives to control pathogenic microorganisms. Among these products, essential oils and plant extracts have previously shown antimicrobial activity and are possible alternatives to manage food pathogens. In this study, commercial essential oils (cinnamon, clove, oregano, ginger, and thyme) and plant extracts (pomegranate, acorn, olive, strawberry tree, and dog rose) were tested against L. monocytogenes in a dry-cured ham-based model.

RESULTS

Essential oils and plant extracts were screened by agar diffusion and minimum inhibitory concentration for anti-L. monocytogenes activity. Cinnamon, pomegranate, and strawberry trees returned the strongest results and were therefore evaluated in a dry-cured ham-based medium assay with water activity of 0.93 or 0.95. The 10% essential oil of cinnamon was capable of completely inhibiting bacterial growth, while strawberry tree and pomegranate extract also showed antilisterial activity (P > 0.05). Water activity influenced the bacterial count of L. monocytogenes in a dry-cured ham-based medium.

CONCLUSIONS

There was a reduction in L. monocytogenes with the application of cinnamon essential oil but, because of the negative sensory impact of this particular compound in meat products, we suggest the use of pomegranate or strawberry tree for the biocontrol of Listeria in ready-to-eat products. © 2021 Society of Chemical Industry.

Comparative Assessment of the Antibacterial Efficacies and Mechanisms of Different Tea Extracts

Tea is a popular beverage known for its unique taste and vast health benefits. The main components in tea change greatly during different processing methods, which makes teas capable of having different biological activities. We compared the antibacterial activity of four varieties of tea, including green, oolong, black, and Fuzhuan tea. All tea extracts showed antibacterial activity and Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) were more susceptible to tea extracts than Gram-negative bacteria (Escherichia coli and Salmonella typhimurium). Green tea extracts inhibited bacterial pathogens much more effectively in all four varieties of tea with the minimum inhibitory concentration (MIC) values at 20 mg/mL, 10 mg/mL, 35 mg/mL, and 16 mg/mL for E. faecalis, S. aureus, E. coli, and S. typhimurium, respectively. Catechins should be considered as the main antibiotic components of the four tea extracts. Total catechins were extracted from green tea and evaluated their antibacterial activity. Additional studies showed that the catechins damaged the cell membrane and increased cell membrane permeability, leading to changes in the relative electrical conductivity and the release of certain components into the cytoplasm. Tea extracts, especially green tea extracts, should be considered as safe antibacterial food additives.

Phenolic-rich extracts from acerola, cashew apple and mango by-products cause diverse inhibitory effects and cell damages on enterotoxigenic Escherichia coli

This study aimed to evaluate the inhibitory effects of phenolic-rich extracts from acerola (Malpighia emarginata D.C., PEA), cashew apple (Anacardium occidentale L., PEC) and mango (Mangifera indica L., PEM) by-products on distinct enterotoxigenic Escherichia coli (ETEC) strains. The capability of PEA and PEC of impairing various physiological functions of ETEC strains was investigated with multiparametric flow cytometry. Procyanidin B₂ , myricetin and p-coumaric acid were the major phenolic compounds in PEA, PEC and PEM, respectively. PEA and PEC had lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) (MIC: 31·25 mg ml^-1 ; MBC: 62·5 mg ml^-1 ) on ETEC strains than PEM (MIC and MIC: >1000 mg ml^-1 ). PEA and PEC (15·6, 31·2, 62·5 mg ml^-1 ) caused viable count reductions (P < 0·05) on ETEC strains after 24 h of exposure, notably the ≥3 log reductions caused by 62·5 mg ml^-1 . The 24 h exposure of ETEC strains to PEA and PEC (31·2, 62·5 mg ml^-1 ) led to high sizes of cell subpopulations with concomitant impairments in cell membrane polarization and permeability, as well as in enzymatic, respiratory and efflux activities. PEA and PEC are effective in inhibiting ETEC through a multi-target action mode with disturbance in different physiological functions.

Insight in the Recent Application of Polyphenols From Biomass

Biomass polyphenols are bio-active macromolecules with distinct chemical structures in a variety of biomass. In recent years, the study of biomass polyphenols and their application in food and medicine fields has become a research hotspot, which predominantly focuses on the preparation, purification, structural identifications, and measurements of biological activities. Many studies describe methodologies for extraction and application of polyphenols, but comprehensive work to review its physiological activities like drugs and health products are lacking. This paper comprehensively unlocks the bioactivities of antioxidant, antibacterial, antitumor, anticancer, neuroprotection, control of blood sugar, regulation of blood fat, and promotion of gastrointestinal health functions of polyphenols from different biomass sources. This review will serve as an illuminating resource for the global scientific community, especially for those who are actively working to promote the advances of the polyphenols research field.

Extraction, isolation, characterization and antimicrobial activities of non-extractable polyphenols from pomegranate peel

Non-extractable polyphenols (NEPPs) in pomegranate peel were released by acid hydrolysis followed by extraction using ethyl acetate (EtOAc). Ten NEPPs were identified in the hydrolysate using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Six compounds were then isolated from the EtOAc extracts whose structures were identified as β-sitosterol-3-O-glycoside (1), β-sitosterol (2), ursolic acid (3), corosolic acid (4), asiatic acid (5) and arjunolic acid (6) using a wide range of spectroscopic analyses. Compounds 4-6 were isolated for the first time from pomegranate peel. Antimicrobial experiments revealed that compound 3 and 5 showed significant antimicrobial activity against a range of pathogens, particularly compound 5 which exhibited selective inhibitive activity towards Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 16 μg/ml. The present study has provided new insights into the composition of bound chemicals in pomegranate peel and laid a foundation for improving its further processing and utilization.

Fabrication and characterization of novel antibacterial chitosan/dialdehyde guar gum hydrogels containing pomegranate peel extract for active food packaging application

This study aimed to investigate synthesis and structural characteristics of the chitosan (CS) - modified dialdehyde guar gum (DAGG) hydrogel through the Schiff base reaction. The highest swelling capacity was achieved as about 12,000% of dry weight of the freeze-dried powder at CS: DAGG hydrogel with the mixing ratio of 30:70. The swelling ratio was not affected by changes in pH, which could be considered as an important property in the control of moisture in absorbent pad. The FTIR results indicated that the new amide groups have been formed at 1680 cm^-1, which can be attributed to the covalent bond between the amide groups of CS and the aldehyde groups of GG. Based on a SEM image, the prepared hydrogel showed the porous structure so it verified the crosslinking formation between the two polymers. Rheological analyses confirmed that formation compact and porous structure led to some noteworthy improvements in the strength of hydrogel prepared with a high ratio of DAGG. The hydrogel loaded with 5% pomegranate peel extract (PPE) showed both good antioxidant (81.13%) and antimicrobial activities. The hydrogel was observed to have a good potential to be used as an antibacterial pad.

Pomegranate Peel Powder as a Food Preservative in Fruit Salad: A Sustainable Approach

This study aimed to assess the potential of pomegranate peel powder as a natural preservative. Its effects were tested on fruit salad quality decay during refrigerated storage. Nectarine and pineapple, equally portioned in polypropylene containers and covered with fructose syrup, were closed using a screw cap in air, with and without the addition of a by-product peel powder. Specifically, amounts of 2.5% and 5% (w/v) of pomegranate peel powder were put into each container. Both the microbiological and sensory qualities of the fruit salad were monitored during storage at 5 °C for 28 days. The results demonstrated that the fruit salad with the by-products showed lower counts of total mesophilic bacteria, total psychrotrophic microorganisms, yeasts, and lactic acid bacteria compared to the control, thus confirming the recognized antimicrobial properties of pomegranate peel. The other interesting finding of this study is that the addition of the investigated by-product in fruit salad did not worsen the main sensory attributes of fresh-cut fruit. Therefore, these preliminary results suggest that pomegranate peel powder has potential applications as a natural preservative in the fresh-cut food sector.

Antiviral Effects of Pomegranate Peel Extracts on Human Norovirus in Food Models and Simulated Gastrointestinal Fluids

Human noroviruses (HuNoV) are the dominant cause of viral gastroenteritis in all age groups worldwide. In this study, we investigated the effects of pomegranate peel extract (PPE) on the reduction of HuNoV in different food models, on surfaces of fresh produce (green onion and cherry tomato), in low-fat milk, and simulated gastrointestinal fluids. The antiviral efficacy of PPE against HuNoV was evaluated by quantifying the number of residual virus genomes using a quantitative reverse transcription PCR (qRT-PCR) assay. Pomegranate peel, considered as a waste product of industrial processing, is known for beneficial health effects and broad antimicrobial activity due to the high content of phenolic compounds and tannins. PPE showed significant antiviral properties against HuNoV both in phosphate-buffered saline (PBS) and simulated gastric fluid. The reduction of HuNoV by pomegranate juice was lower than with PPE, which could be attributed to the lower content of antimicrobial compounds. A pretreatment of cherry tomato and green onion surfaces with PPE significantly reduced the amount of HuNoV particles that adhered to those surfaces during subsequent virus suspension treatment. A detrimental effect of PPE on HuNoV structure was confirmed by transmission electron microscopy. Our results indicate that PPE is a natural antiviral agent effective against food-borne noroviruses.

Chitosan Nanoparticles as a Promising Nanomaterial for Encapsulation of Pomegranate (Punica granatum L.) Peel Extract as a Natural Source of Antioxidants

The encapsulation of pomegranate peel extract (PPE) in chitosan nanoparticles (CSNPs) is an advantageous strategy to protect sensitive constituents of the extract. This study was aimed to develop PPE-loaded CSNPs and characterize their physical, structural morphology, antioxidant and antimicrobial properties. Spherical NPs were successfully synthesized with a mean diameter of 174–898 nm, a zeta potential (ZP) of +3 – +36 mV, an encapsulation efficiency (EE) of 26–70%, and a loading capacity (LC) of 14–21% depending on their loaded extract concentrations. Based on these results, CSNPs with chitosan:PPE ratio of 1:0.50 (w/w) exhibited good physical stability (ZP = 27 mV), the highest loading (LC = 20%) and desirable encapsulation efficiency (EE = 51%), and thus, selected as optimally loaded NPs. The FTIR analysis of PPE-CSNPs demonstrated no spectral changes indicating no possible chemical interaction between the PPE and CSNPs, which confirms that the PPE was physically entrapped within NPs. Moreover, FTIR spectra of pure PPE showed specific absorption bands (at 3293–3450 cm⁻¹) attributed to the incidence of phenolic compounds, such as tannic acid, ellagic acid and gallic acid. Total phenolic content (TPC) and antioxidant analysis of selected CSNPs revealed that the encapsulated NPs had significantly lower TPC and antioxidant activity than those of pure PPE, indicating that CSNPs successfully preserved PPE from rapid release during the measurements. Antibacterial tests indicated that pure PPE and PPE-loaded CSNPs effectively retarded the growth of Gram-positive S. aureus with a minimum inhibitory concentration (MIC) of 0.27 and 1.1 mg/mL, respectively. Whereas Gram-negative E. coli, due to its protective cell membrane, was not retarded by pure PPE and PPE-CSNPs at the MIC values tested in this study. Gas chromatography-mass spectroscopy analysis confirmed the incidence of various phytochemicals, including phenolic compounds, fatty acids, and furfurals, with possible antioxidant or antimicrobial properties. Overall, CSNPs can be regarded as suitable nanomaterials for the protection and controlled delivery of natural antioxidants/antimicrobials, such as PPE in food packaging applications.

A unique understanding of traditional medicine of pomegranate, Punica granatum L. and its current research status

ETHNOPHARMACOLOGICAL RELEVANCE

Pomegranate, Punica granatum L., has been used in traditional medicine in China and several regions of the world including Ayurveda, Islamic, and Persian for the treatment of atherosclerosis, diabetes, hypertension, hyperlipidemia, and several types of cancer, as well as for peptic ulcer and oral diseases for hundreds of years. Presently, pomegranate is treated as both a "medicine food homology" herbal medicine and a healthy food supplemental product.

AIM OF THE STUDY

The aim of this work is to develop an overview of pomegranate in the context of the status of its traditional medicine theories, the spread along the Silk Road, ethnopharmacological uses, chemical compositions, pharmacological activities, toxicology, and the involved pathways.

MATERIALS AND METHODS

Information on P. granatum L. was acquired from published materials, including monographs on medicinal plants, ancient and modern recorded classical texts; and pharmacopoeias and electronic databases (PubMed, Science Direct, Web of Science, Google Scholar, CNKI, and Wanfang Data).

RESULTS

Pomegranate has been used in many traditional medical systems throughout history. It is widely cultivated in Central Asia and spread throughout China along the Silk Road. Many phytochemicals, such as tannins, organic acids, flavonoids, alkaloids, and volatile oils have been identified from different parts of pomegranate, these compounds have a wide range of activities, including antioxidant, antimicrobial, and anti-oncogenic properties, as well as conferring resistance to cerebrovascular disease. Furthermore, A summary of the four promising pharmacological pathways is provided.

CONCLUSIONS

The traditional uses, chemical compositions, pharmacological activities, and signaling pathways of pomegranate are summarized comprehensively in the review. It can be treated as a guidance for the future clinical and basic research. The information provided in this review will be very useful for further studies to develop novel therapeutic directions for application of pomegranate.