Incorporation of Zataria multiflora Boiss essential oil into gum Arabic edible coating to maintain the quality properties of fresh in-hull pistachio (Pistacia vera L.)

Characterizing the antioxidant and antifungal properties of nano-encapsulated pistachio hull extract in fenugreek seed gum to maintain the quality and safety of fresh pistachio

The quality of pistachio, one of the export products of Iran, will be decreased during storage as a result of mold spoilage, toxins production, and oil oxidation. This study aimed to investigate the capability of pistachio hull extract (PHE) loaded in fenugreek seed gum (FSG):whey protein isolate (WPI) nanoemulsion to control oil oxidation, and fungi growth in fresh pistachio nut during storage at 4°C. The total anthocyanin and total phenolic content of the PHE were 125.44 μg/g and 675.18 mg/g, respectively. The DPPH radical scavenging activity of PHE at 100 ppm was higher than that of tert-butylhydroquinon (TBHQ). In comparison with other concentrations, 50 ppm showed the strongest antifungal activity against Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius. All nanoemulsions have a mean size lower than 265 nm. The polydispersity index (PDI) of different nanoemulsions was lower than 0.3, and a negative zeta potential was observed. The encapsulation efficiency was higher than 67.0% and all nanoemulsions had spherical morphology. The pistachio nuts were coated with different coating solutions containing 0 and 100 ppm of PHE and stored at 4°C for 8 weeks. The results showed that the pistachio sample coated with a composite coating of WPI and FSG containing 100 ppm of PHE has a higher moisture content and lower changes in L*, a*, and b* indexes, oil oxidation, fungi development, and total mold and yeast count. This treatment exhibited higher overall acceptance than other samples at the end of storage time. The results of this study suggest the use of biodegradable coatings enriched with natural extracts that have high antioxidant and antifungal activities.

Application of essential oils as slow-release antimicrobial agents in food preservation: Preparation strategies, release mechanisms and application cases

Food spoilage caused by foodborne microorganisms will not only cause significant economic losses, but also the toxins produced by some microorganisms will also pose a serious threat to human health. Essential oil (EOs) has significant antimicrobial activity, but its application in the field of food preservation is limited because of its volatile, insoluble in water and sensitive to light and heat. Therefore, in order to solve these problems effectively, this paper first analyzed the antibacterial effect of EOs as an antimicrobial agent on foodborne bacteria and its mechanism. Then, the application strategies of EOs as a sustained-release antimicrobial agent in food preservation were reviewed. On this basis, the release mechanism and application cases of EOs in different antibacterial composites were analyzed. The purpose of this paper is to provide technical support and solutions for the preparation of new antibacterial packaging materials based on plant active components to ensure food safety and reduce food waste.

Probiotic-loaded seed mucilage-based edible coatings for fresh pistachio fruit preservation: an experimental and modeling study

In this study, Lallemantia royleana mucilage (LRM) based edible coating containing 1.5 × 108 and 3 × 109 CFU/mL Lacticaseibacillus casei XN18 (Lbc1.5 and Lbc3) was designed to improve the quality and shelf-life of fresh pistachio. The fresh pistachios were coated with LRM + Lbc and their physicochemical, microbial, and sensory properties were evaluated after 1-, 5-, 15-, 25-, and 35-day storage at 4 °C. By the end of storage day, in comparison to control, the presence of probiotic isolate in the edible coating (particularly LRM + Lbc3) led to a marked decrease in fungal growth (3.1 vs. 5.8 Log CFU/g), weight loss (6.7 vs. 8.1%), and fat oxidation (0.19 vs. 0.98 meq O2/kg), and preserved total chlorophylls (8.1 vs. 5.85 mg/kg) and phenols (31.5 vs. 20.32 mg GAE/100 g), and antioxidant activity (38.95 vs. 15.18%) of samples during storage period. Furthermore, LRM + Lbc3-coated samples had a probiotic number above the recommended level (6.85-9.29 log CFU/g) throughout storage. The pistachios coated with probiotic-enriched edible coatings were greatly accepted by panelists. In the next section, Gaussian Process Regression (GPR) was used for predicting some parameters including: weight loss, TSS, Fat content, PV, Soluble carbohydrate content, Viability, Total phenolic compounds, Antioxidant activity, Mold and yeast, Total chlorophylls, Total carotenoids, Color, Odor and Overall acceptance. The results indicated that, there is a good agreement between the actual and predicted data by GPR model and it can be used for similar situation to decrease the cost of laboratory tests and increase the respond of analysis.

Effect of Chitosan-24-Epibrassinolide Composite Coating on the Quality Attributes of Late-Harvested Pomegranate Fruit under Simulated Commercial Storage Conditions

This study evaluated the efficacy of chitosan (CH) functionalized with 24-epibrassinolide (EBR) coating in terms of preserving the postharvest quality of late-harvested pomegranate (cv. Wonderful) fruit. Late-harvested pomegranate fruit were immersed for 3 min in different surface treatment solutions—CH 1.5% (w/v), CH + 2 µM EBR, CH + 5 µM EBR, CH + 10 µM EBR and CH + 15 µM EBR—and distilled water was used as a control treatment. The fruit were air-dried and subjected to long storage duration at 5 °C with 85 ± 5 RH for 12 weeks. At 4-week sampling intervals, a batch of fruits was placed at 21 ± 2 °C and 65–70% RH for a further 3 d period to simulate retail conditions before measurements were taken. Fruit physiological responses, physico-chemical properties, phytochemical contents, antioxidant capacity and physiological disorders were monitored during storage. The results showed that the CH-EBR composite edible coatings significantly (p < 0.05) delayed degradative processes due to senescence. The CH-EBR treatments delayed colour, texture and total soluble solids (TSS) degradation and reduced weight loss, respiration, electrolyte leakage and spoilage compared to the control and CH treatment. The treatment effect was more noticeable on fruit treated with CH + 10 µM EBR, which exhibited lower weight loss (18.19%), respiration rate (7.72 mL CO₂ kg⁻¹ h⁻¹), electrolyte leakage (27.54%) and decay (12.5%), and maintained higher texture (10.8 N) and TSS (17.67 °Brix) compared to the untreated fruit with respective values of 24.32%, 18.06 mL CO₂ kg⁻¹ h⁻¹, 43.15%, 37.5%, 8.32 N and 17.03 °Brix. This was largely attributed to the significantly higher antioxidant content, including the ascorbic acid content, total phenol content, total anthocyanin content and DPPH (radical scavenging activity), of the coated fruit compared to the control fruit. Therefore, CH + 10 µM EBR treatment is recommended as a postharvest management strategy to improve the quality preservation of late-harvested pomegranate fruit during storage.

Polysaccharide-Based Active Coatings Incorporated with Bioactive Compounds for Reducing Postharvest Losses of Fresh Fruits

This review reports recently published research related to the application of polysaccharide-based biodegradable and edible coatings (BECs) fortified with bioactive compounds obtained from plant essential oils (EOs) and phenolic compounds of plant extracts. Combinations of polysaccharides such as starches, pectin, alginate, cellulose derivatives, and chitosan with active compounds obtained from clove, lemon, cinnamon, lavender, oregano, and peppermint have been documented as potential candidates for biologically active coating materials for retardation of quality changes in fresh fruits. Additionally, polysaccharide-based active coatings supplemented with plant extracts such as cashew leaves, pomegranate peel, red roselle, apple fiber, and green tea extracts rich in phenolic compounds and their derivatives have been reported to be excellent substituents to replace chemically formulated wax coatings. Moreover, EOs and plant polyphenolics including alcohols, aldehydes, ketones phenols, organic acids, terpenes, and esters contain hydroxyl functional groups that contribute bioactivity to BECs against oxidation and reduction of microbial load in fresh fruits. Therefore, BECs enriched with active compounds from EOs and plant extracts minimize physiological and microbial deterioration by reducing moisture loss, softening of flesh, ripening, and decay caused by pathogenic bacterial strains, mold, or yeast rots, respectively. As a result, shelf life of fresh fruits can be extended by employing active polysaccharide coatings supplemented with EOs and plant extracts prior to postharvest storage.

Gum Arabic Nanoparticles as Green Corrosion Inhibitor for Reinforced Concrete Exposed to Carbon Dioxide Environment

The inhibiting effect of Gum Arabic-nanoparticles (GA-NPs) to control the corrosion of reinforced concrete that exposed to carbon dioxide environment for 180 days has been investigated. The steel reinforcement of concrete in presence and absence of GA-NPs were examined using various standard techniques. The physical/surface changes of steel reinforcement was screened using weight loss measurement, electrochemical impedance spectroscopy (EIS), atomic force microscopy and scanning electron microscopy (SEM). In addition, the carbonation resistance of concrete as well screened using visual inspection (carbonation depth), concrete alkalinity (pH), thermogravimetric analysis (TGA), SEM, energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The GA-NPs inhibitor size was also confirmed by transmission electron microscopy (TEM). The results obtained revealed that incorporation of 3% GA-NPs inhibitor into concrete inhibited the corrosion process via adsorption of inhibitor molecules over the steel reinforcement surface resulting of a protective layer formation. Thus, the inhibition efficiency was found to increase up-to 94.5% with decreasing corrosion rate up-to 0.57 × 10⁻³ mm/year. Besides, the results also make evident the presence of GA-NPs inhibitor, ascribed to the consumption of calcium hydroxide, and reduced the Ca/Si to 3.72% and 0.69% respectively. Hence, C-S-H gel was developed and pH was increased by 9.27% and 12.5, respectively. It can be concluded that green GA-NPs have significant corrosion inhibition potential and improve the carbonation resistance of the concrete matrix to acquire durable reinforced concrete structures.

Effect of Sodium Alginate in Combination with Zataria multiflora Boiss. on Phenolic Compounds, Antioxidant Activity, and Browning Enzymes of Fresh In-Hull Pistachio (Pistacia vera L.)

The color of fresh pistachio is used as a postharvest quality indicator. The present study was performed to investigate the chemical properties of fresh pistachios coated with different sodium alginate concentrations (1 and 1.5%), various amounts of Shirazi thyme essential oil (0.3 and 0.5%), and their combination during storage (2 ± 1°C and 85 ± 5% RH). Over the storage duration, chemical parameters were measured on days 13, 26, and 39. The results showed that although the application of sodium alginate in combination with thyme essential oil decreased polyphenol oxidase activity in comparison with other treatments, the highest total phenolics and phenylalanine ammonia lyase activity were found in pistachios coated with alginate (1%) + thyme essential oil (0.3% and 0.5%). In general, it was proven that treatments containing 1% alginate + 0.3% essential oil had the ability to maintain the quality of fresh pistachio fruit approximately over 39 days of storage.