Valorization of various nut residues grown in Turkiye: Antioxidant, anticholinesterase, antidiabetic, and cytotoxic activities

The utilization of plant-based residues has been extensively employed for the control of diverse illnesses, owing to their safety and minimal adverse effects. In the current study, it was aimed for the characterization of the bioactive, enzyme inhibitory, and cytotoxic activities of fresh pistachio shell skin (FPSS), green walnut husk and walnut membrane (GWH), almond outer shell and inner brown skin (ASIS), as well as peanut husk and inner skin (PHIS) to be used as industrial food processing by-products. The results showed that the samples exhibited different extraction yields, with GWH having the highest percentage at 15.18%, followed by FPSS at 12.81%, ASIS at 10.29%, and PHIS at 7.80%. FPSS had the highest total phenolic content (16.28 mg gallic acid equivalents (GAE)/g) as well as the best antioxidant capabilities for DPPH (8.96 mg Trolox equivalent (TE)/g), FRAP (11.46 mg TE/g), and ABTS (22.38 mg TE/g) assays. FPSS was followed by PHIS, ASIS, and GWH, respectively. Moreover, the extracts exhibited relatively low activity against acetylcholinesterase, α-glucosidase, and α-amylase compared to standard acarbose or galantamine. Furthermore, the extracts may have the potential to induce cytotoxic effects, varying from moderate to mild, on both cancerous (IC50 = 454.55-617.28 μg/mL) and healthy cells (IC50 = 438.60-490.20 μg/mL). The results of this research showed that shell residues of nut hold promise for a variety of industrial applications spanning the food, pharmaceutical, and cosmetic sectors.

GC-MS profiling of Pistachio vera L., and effect of antioxidant and antimicrobial compounds of it's essential oil compared to chemical counterparts

All elements of the pistachio tree are considered raw pistachio by-products. The soft hull makes up the majority of these by-products. It contains proteins, fats, minerals, vitamins, phenolics contents (TPC), and antioxidants. Early smiling pistachios are one of the most important sources of pistachio contamination with aflatoxin in the garden and processing stages. The present study aimed to evaluate pistachio hull essential oil (EO) composition, and antioxidant and antimicrobial properties under in vitro conditions. TPC, antioxidant, and antimicrobial activity were measured using the Folin-Ciocalteu reagent, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method, and serial dilution titration method, respectively. A gas chromatography system with a mass spectrometer (GC-MS) was utilized to determine the chemical components of the EO. The findings revealed that the quantity of TPC and anti-radical activity in IC50 were 245.43 mg gallic acid/mL and 206.32 µL/L, respectively. The free radical absorption activity of DPPH (%) increased with EO content. The inhibitory activity of EO on Staphylococcus aureus and Bacillus subtilis was much lower than that of streptomycin and penicillin. Aspergillus flavus was effectively inhibited by pistachio hull EO, comparable to fluconazole. The results obtained from GC-MS showed that the major compounds in pistachio hull essential oil include α-pinene (47.36%), terpinolene (10.57%), limonene (9.13%), and L-bornyl acetate (8.57%). The findings indicated that pistachio hull EO has potent antibacterial and antioxidant components and can be employed as a natural antimicrobial and antioxidant in food systems.

Evaluation of bioactivities of Pistacia vera L. hull extracts as a potential antimicrobial and antioxidant natural source

Pistacia vera L. hull, a the major byproduct of pistachio processing, is a source of functional compounds with antioxidant and antimicrobial activities. The extraction of these natural compounds from pistachio hulls and their use instead of synthetic chemicals has gained great attention. In this work, the phytochemical contents and antioxidant and antimicrobial activities of pistachio hull ethanolic (PVE) and aqueous (PVD) extracts obtained by microwave-assisted extraction (MAE) were investigated. Gallic acid (1.9 and 1.5 mg g-1 dw), quercetin (0.025 and 0.009 mg g-1 dw), total phenolic (23.3 and 14.7 mg GAE g-1 dw) and flavonoid (5.0 and 2.9 mg QE g-1 dw) contents and antioxidant activities (SC50 0.63 and 0.56 mg mL-1) of PVE and PVD extracts were determined, respectively. The extracts exhibited antimicrobial effects against Enterococcus faecalis, Staphylococcus aureus, Streptococcus uberis, Bacillus cereus, and Bacillus subtilis. Minimal inhibitory concentrations (MICs, 0.8-49.0 and 9.6-82.5 mg mL-1) and the minimal bactericidal concentrations (MBCs, 1.3-99.1 and 15.5-150.0 mg mL-1) of PVE and PVD extracts were determined, respectively. Kill curves revealed that PVE and PVD extracts could inhibit the growth of bacteria. It was shown that PVE and PVD extracts could represent a good economical source of functional and bioactive compounds.

Advances in the Role and Mechanisms of Essential Oils and Plant Extracts as Natural Preservatives to Extend the Postharvest Shelf Life of Edible Mushrooms

China has a large variety of edible mushrooms and ranks first in the world in terms of production and variety. Nevertheless, due to their high moisture content and rapid respiration rate, they experience constant quality deterioration, browning of color, loss of moisture, changes in texture, increases in microbial populations, and loss of nutrition and flavor during postharvest storage. Therefore, this paper reviews the effects of essential oils and plant extracts on the preservation of edible mushrooms and summarizes their mechanisms of action to better understand their effects during the storage of mushrooms. The quality degradation process of edible mushrooms is complex and influenced by internal and external factors. Essential oils and plant extracts are considered environmentally friendly preservation methods for better postharvest quality. This review aims to provide a reference for the development of new green and safe preservation and provides research directions for the postharvest processing and product development of edible mushrooms.

Evaluation of Phenolic Profile and Antioxidant Activity of Eleven Pistachio Cultivars (Pistacia vera L.) Cultivated in Andalusia

Pistachio (Pistacia vera L.) is a nut with a good adaptability to the Mediterranean conditions of cultivation, specifically in the Andalusian region, becoming an emerging crop. Moreover, it has been getting attention in the past years for the great content of bioactive compounds such as polyphenols. Although some studies have reported the polyphenolic profile of pistachios, most of them have analyzed the hull part, considered as a residue, and not the kernel which is the edible part. Therefore, characterization of eleven varieties of pistachios kernels cultivated in Andalusia and harvested in 2019 and 2020 was carried out by UHPLC-MS (ultra-high-performance liquid chromatography high-resolution mass spectrometry). The identification and quantification of 56 polyphenolic compounds was performed, being the hydroxybenzoic acids group the most abundant with a 71−86% of the total amount followed by flavan-3-ols group that accounted for 8−24%. Moreover, 3,4-dihydroxybenzoic acid was the main compound in most of the varieties, followed by vanillic acid hexoside. Larnaka, Avdat, Aegina, and Mateur presented the highest amount of total polyphenols, while Kalehghouchi, Joley, Lost Hills, Kerman, and Golden Hills were the varieties with the lowest content. Regarding the harvest season, no significant differences (p < 0.01) were found in the total amount of polyphenols between 2019 and 2020. In addition, the antioxidant activity was measured by DPPH (1,1-diphenyl-2-picryl-hydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), and ORAC (oxygen radical absorbance capacity) assays, showing a similar trend as that of the polyphenols.

Pistachio Hull Extract as a Practical Strategy to Extend the Shelf Life of Raw Minced Beef: Chemometrics in Quality Evaluation

The agricultural processing industry produces a notable quantity of by-products rich in bioactive compounds, which can be exploited for agri-food applications. From pistachio industrial processing, pistachio's hull is one of the major by-products. This work aimed to evaluate the potential of pistachio hull, as a potential source of natural antioxidant, to preserve the meat quality. Here, we investigated the impact of aqueous pistachio hull extract (PHE) at 0.156% (PHE1), 0.312% (PHE2), and 0.625% (PHE3) on the quality of raw minced beef meat stored for 14 days at 4°C. At the end of storage, mesophilic total viable plate, psychotropic and Enterobacteriaceae counts, showed significantly lower (P < 0.05) microbial count in PHE samples. PHE3 revealed a powerful inhibitory effect on lipid/protein oxidation, and sensory characteristics were positively (P < 0.05) affected. Principal component analysis and heat map indicated complex and close synchronized relations among lipid/protein oxidation processes, microbial loads, and sensory attributes. Obtained results using univariate and multivariate statistical analysis underlined the importance of using different mathematical approaches, which are complementary to each other and could provide considerable information about the minced beef meat treated by PHE. Therefore, compared to synthetic antioxidants, PHE could be a clean-label alternative that can protect and enhance the quality of meat products.

Tunisian Pistachio Hull Extracts: Phytochemical Content, Antioxidant Activity, and Foodborne Pathogen Inhibition

The present study aimed to discriminate pistachio (Pistacia vera L.) hulls belonging to three different Tunisian geographical origins and extracted separately by hexane, acetone, acetonitrile, and water in terms of phytochemicals and antioxidant and antibacterial activities using multivariate analysis. Significant differences ( $P<0.05$ ) in the phytochemical content, antioxidant, and antifoodborne bacterial activities were detected among the pistachio hulls populations. Pearson correlation, principal component analysis (PCA), hierarchical cluster analysis (HCA), and heat map were used to distinguish the relationship between the different regions on the basis of the biological activities. It was found that the twelve (4 extracts × 3 geographical sources) pistachio hulls extracts could be classified geographically into four distinct groups. To explore the mode of action of the aqueous pistachio hull extract against L. monocytogenes and S. enterica, polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol (PALCAM) and xylose lysine deoxycholate (XLD) broth media were artificially contaminated at 104 CFU/mL. Using linear and general linear models, aqueous pistachio hull extract was demonstrated to control the two dominant food-borne pathogens by suppressing the bacterial growth.

Antioxidant Molecules from Plant Waste: Extraction Techniques and Biological Properties

The fruit, vegetable, legume, and cereal industries generate many wastes, representing an environmental pollution problem. However, these wastes are a rich source of antioxidant molecules such as terpenes, phenolic compounds, phytosterols, and bioactive peptides with potential applications mainly in the food and pharmaceutical industries, and they exhibit multiple biological properties including antidiabetic, anti-obesity, antihypertensive, anticancer, and antibacterial properties. The aforementioned has increased studies on the recovery of antioxidant compounds using green technologies to value plant waste, since they represent more efficient and sustainable processes. In this review, the main antioxidant molecules from plants are briefly described and the advantages and disadvantages of the use of conventional and green extraction technologies used for the recovery and optimization of the yield of antioxidant naturals are detailed; finally, recent studies on biological properties of antioxidant molecules extracted from plant waste are presented here.

Gallic Acid an Agricultural Byproduct Modulates the Biofilm Matrix Exopolysaccharides of the Phytopathogen Ralstonia solanacearum

Ralstonia solanacearum is a soil-borne plant pathogen which causes wilt disease in economically important crops of the Solanaceae family in tropical and temperate regions. As biofilm formation is the major virulence factor in R. solanacearum, research inputs are necessary to identify natural biofilm inhibitors to mitigate virulence of this bacterium. Hence in the present work, the anti-biofilm potential of phytochemical compound gallic acid (GA) isolated from an agricultural byproduct (cashewnut shell) was investigated. Initially the Minimum inhibitory concentration (MIC) of crude extracts of cashewnut shell and coconut shell against R. solanacearum were investigated. The MIC of both the extracts were 400 µg/ml and their sub-MIC (200 µg/ml) inhibited biofilms in the range of 62-70% and 49-57%, respectively. As the cashewnut shell extract have higher biofilm inhibitory effect compared to coconut shell extract, we proceeded our further study by isolating the major compound GA from cashewnut shell by acid hydrolysate method. The sub-MIC of crude cashewnut shell extract inhibited 85% of young biofilms. The MIC of GA were observed at 3 mg/ml and sub-MIC (1.5 mg/ml) was found to eradicate 85% of mature biofilms which was confirmed by standard crystal violet assay and the biofilm reduction was further visualized under light microscopy and scanning electron microscopic images. Toxicity of GA was evaluated against R. solanacearum through XTT cell viability assay and found no antibacterial effect at sub-MIC. Additionally, it is confirmed with growth curve and time kill assays. Swimming and twitching motility were considered as an important virulence factors to invade plants and to block the xylem vessels. Therefore, sub-MIC of GA was found to inhibit both swimming and twitching motility of about 93% and 63% respectively. Anti-biofilm efficacy of GA was also worked well with tomato plant model where remarkable biofilm inhibition was found on treatment with GA before and after 24 h of infection with R. solanacearum. Hence GA will be an alternative, cheap source which is eco-friendly as well as novel source for the treatment of R. solanacearum biofilms and to prevent wilt disease in important crops.

Antidiabetic and Anticholinesterase Properties of Extracts and Pure Metabolites of Fruit Stems of Pistachio (Pistacia vera L.)

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Five metabolites were isolated by chromatographic methods from the fruit stems of P. vera and their chemical structures were characterized as masticadienonic acid (1), tirucallol (2), masticadienolic acid (3), pistachionic acid (4) and inulobiose (5) via FT-IR, 1H-NMR, 13C-NMR, 1D-NMR and 2D-NMR. Pistachionic acid (4), a new shikimic acid derivative, was isolated from the ethanol extract for the first time. The hexane, chloroform, ethanol extracts and pure metabolites exhibited antidiabetic properties by inhibiting α- glycosidase and α-amylase enzymes at different rates. Their inhibitory effects against the α- glycosidase enzyme were also higher than that of the acarbose (IC50=10.30 mg/mL). Masticadienolic acid (3) (IC50=0.03 mg/mL), masticadienonic acid (1) (IC50=0.13 mg/mL) and hexane extract (IC50=0.09 mg/mL) with the lowest IC50 values were found to be most active substances. Nevertheless, the inhibitory effect of acarbose against the α-amylase enzyme was determined to be higher than the inhibition effects of the extracts and pure metabolites. According to the IC50 values, the best inhibitors against the α-amylase were ethanol extract (IC50=5.17 mg/mL), pistachionic acid (4) (IC50=7.35 mg/mL), tirucallol (2) (IC50=7.58 mg/mL) and masticadienolic acid (3) (IC50=8.22 mg/mL), respectively among the applications. In addition, anticholinesterase properties of the extracts and pure metabolites were investigated by testing the inhibitory properties against acetylcholine esterase (AChE) and butrylcholine esterase (BChE) enzymes activities. The results showed that the anticholinesterase properties of all extracts and pure metabolites were weaker than those of the commercial cholinesterase inhibitors, neostigmine and galantamine, and all applications reduced the activity of these enzymes at very high concentrations.

Subcritical water extraction of phenolic and antioxidant constituents from pistachio (Pistacia vera L.) hulls

Pistachio hulls, important by-products of pistachio processing, were extracted using an environmentally friendly process with subcritical water (SCW) at a pressure of 6.9 MPa in the range of 110 and 190 °C, and a flow rate of 4 ml/min. Detailed HPLC-DAD-ESI/MSⁿ analyses allowed the identification of 49 phenolic compounds in the SCW extracts. Total gallotannin yields up to 33 g/kg were reached at 150-170 °C, where gallic acid (22.2 g/kg) and penta-O-galloyl-β-d-glucose (9.77 g/kg) levels were 13.2- and 10.6-fold higher than those in the aqueous methanol extracts. Flavonols were also effectively extracted at 110-150 °C (4.37-5.65 g/kg), while anacardic acid recovery was poor (1.13-2.77 g/kg). Accordingly, high amounts of anacardic acids (up to 50.7 g/kg) were retained in the extraction residue, revealing that SCW extraction allowed selective extraction of gallotannins and flavonols. Antioxidant capacities ranged from 0.68 to 1.20 mmol Trolox equivalents (TE)/g for SCW extracts increasing with temperature up 190 °C.

Greenly synthesized graphene with l-glutathione-modified electrode and its application towards determination of rutin

A simple, environmentally friendly and cost-effective approach for preparation of water-soluble functional graphene was proposed for constructing a voltammetric sensor platform.