Effect of chitosan coating enriched with thyme oil on postharvest quality and shelf life of shiitake mushroom (Lentinus edodes)

The effect of chitosan-oil coating on the postharvest quality and shelf life of shiitake (Lentinus edodes) mushrooms stored at 4 ± 1 °C for 16 days was investigated. Mushroom weight loss, firmness, total phenolics, ascorbic acid, malondialdehyde (MDA), electrolyte leakage rate, and microbial and sensory quality were measured. The results indicate that treatment with chitosan-oil coating maintained tissue firmness, inhibited increase of respiration rate, and reduced microorganism counts, such as yeasts and molds and pseudomonad, compared to control treatment. The efficiency was better than that of thyme oil treatment or chitosan coating. Furthermore, shiitake mushrooms treated with chitosan-oil coating also exhibited significantly higher levels of total phenolics, flavonoids, as well as individual phenolic compounds than control. Sensory evaluation proved the efficacy of chitosan-oil coating by maintaining the overall quality of shiitake mushroom during the storage period. Our study suggests that chitosan-oil coating might be a promising candidate for maintaining shiitake mushroom quality and extending their postharvest life.

Antioxidant activity and protecting health effects of common medicinal plants

Medicinal plants are traditionally used in folk medicine as natural healing remedies with therapeutic effects such as prevention of cardiovascular diseases, inflammation disorders, or reducing the risk of cancer. In addition, pharmacological industry utilizes medicinal plants due to the presence of active chemical substances as agents for drug synthesis. They are valuable also for food and cosmetic industry as additives, due to their preservative effects because of the presence of antioxidants and antimicrobial constituents. To commonly used medicinal plants with antioxidant activity known worldwide belong plants from several families, especially Lamiaceae (rosemary, sage, oregano, marjoram, basil, thyme, mints, balm), Apiaceae (cumin, fennel, caraway), and Zingiberaceae (turmeric, ginger). The antioxidant properties of medicinal plants depend on the plant, its variety, environmental conditions, climatic and seasonal variations, geographical regions of growth, degree of ripeness, growing practices, and many other factors such as postharvest treatment and processing. In addition, composition and concentration of present antioxidants, such as phenolic compounds, are related to antioxidant effect. For appropriate determination of antioxidant capacity, the extraction technique, its conditions, solvent used, and particular assay methodology are important.

Optimization of extraction conditions of total phenolics, antioxidant activities, and anthocyanin of oregano, thyme, terebinth, and pomegranate

The purpose of this study was to evaluate the total phenolic extracts and antioxidant activity and anthocyanins of varieties of the investigated plants. These plants include oregano, thyme, terebinth, and pomegranate. The optimum extraction conditions including temperature and solvent of the extraction process itself were investigated. Total phenolic and anthocyanin extracts were examined according to Folin-Ciocalteu assay and Rabino and Mancinelli method, respectively. The effect of different extracting solvents and temperatures on extracts of phenolic compounds and anthocyanins were studied. Plant samples were evaluated for their antioxidant chemical activity by 2, 2-diphenyl-1-picrylhydrazl assay, to determine their potential as a source of natural antioxidant. Results showed that all tested plants exhibited appreciable amounts of phenolic compounds. The methanolic extract (60 °C) of sour pomegranate peel contained the highest phenolic extract (4952.4 mg/100 g of dry weight). Terebinth green seed had the lowest phenolic extract (599.4 mg/100 g of dry weight). Anthocyanins ranged between 3.5 (terebinth red seed) and 0.2 mg/100 g of dry material (thyme). Significant effect of different extracting solvents and temperatures on total phenolics and anthocyanin extracts were found. The methanol and 60 °C of extraction conditions found to be the best for extracting phenolic compounds. The distilled water and 60 °C extraction conditions found to be the best for extracting anthocyanin.

Bioactivity of antioxidants in extruded products prepared from purple potato and dry pea flours

Measuring antioxidant activity using a biologically relevant assay adds important evidence to aid in understanding the role of phytochemicals based on data from in vivo and chemical assays of extrusion processed purple potato and pea flours. A cellular antioxidant activity assay could provide biologically relevant information on bioactive compounds in raw as well as processed food products. The objective of this study was to investigate the complete phytochemical profiles, antioxidant activity, cellular antioxidant activity, and their contribution to bioactivity in purple potato flour, dry pea flour, raw formulations, and extrusion cooked products prepared with the above ingredients. The free fraction of extracts contributed 68, 64, and 88% to total phenolics, total antioxidant activity (ORAC value), and total flavonoids, respectively, in purple potato flour (PPF). Similarly, extracts in the free fraction contributed 87, 86, and 64% to total phenolics, total antioxidant activity (ORAC value), and total flavonoids, respectively, in dry pea flour (DPF). The amount of total phenolics and total flavonoids in purple potato flour and the antioxidant activity of PPF and DPF were comparable to published data. However, a higher amount in the total flavonoids and lower in the total phenolics of DPF were observed. Caffeic, p-coumaric, and ferulic acids were mostly observed in the bound extracts of raw formulations as in the extrudates, whereas chlorogenic acid was predominant in the free extracts. The extruded products had significantly higher (p < 0.05) content of total phenolics, ORAC antioxidant activity, and flavonoids, compared to the raw formulations. Extrusion processing increased the cellular antioxidant activity of the extrudates prepared from 35:65 and 50:50 PPF/DPF (w/w) of ingredients compared with control raw formulations in a dose-dependent manner. Increase of PPF significantly increased (p < 0.05) the cellular antioxidant activity of 35-50% PPF formulations.

Time-dependent effects of pomegranate juice and pomegranate polyphenols on foodborne viral reduction

Pomegranate juice (PJ) and pomegranate polyphenolic extracts (PP) have antiviral effects against HIV-1, influenza, herpes, and poxviruses, and we recently demonstrated their effect against human noroviral surrogates. In the present study, the time-dependent effects of two commercial brands of PJ and PP at two concentrations (2 and 4 mg/mL) on the infectivity of foodborne viral surrogates (feline calicivirus FCV-F9, murine norovirus MNV-1, and MS2 bacteriophage) at room temperature for up to 1 h were evaluated. Each virus at ∼5 log(10) plaque-forming units (PFU)/mL was mixed with equal volumes of PJ, or PP at 4 or 8 mg/mL, and incubated for 0, 10, 20, 30, 45, and 60 min at room temperature. Viral titers after each treatment were determined by standardized plaque assays and compared with untreated controls. Virus titer reduction by PJ and PP was found to be a rather rapid process, with ≥50% of titer reduction occurring within the first 20 min of treatment for all three tested viruses. Within the first 20 min, titer reductions of 3.12, 0.79, and 0.23 log(10) PFU/mL for FCV-F9, MNV-1, and MS2, respectively, were obtained using PJ. FCV-F9, MNV-1, and MS2 titers were reduced by 4.02, 0.68, and 0.18 log(10) PFU/mL with 2 mg/mL PP and 5.09, 1.14, and 0.19 log(10) PFU/mL with 4 mg/mL PP, respectively, after 20 min. The mechanism of viral reduction by PJ and PP needs to be elucidated and clinical trials should be undertaken before recommending for therapeutic or preventive purposes.

Antioxidant acitivity of low molecular weight hyaluronic acid

Two polysaccharides, low molecular weight hyaluronic acid-1 (LMWHA-1) and LMWHA-2, with their molecular weight of 1.45×10(5) and 4.52×10(4)Da, respectively, were prepared from high molecular weight hyaluronic acid (HA,1.05×10(6)Da). LMWHA-1, LMWHA-2 and HA were studied for their antioxidant activities. In vitro antioxidant assay, LMWHA showed strong inhibition of lipid peroxidation and scavenging activities of hydroxyl radical, moderate 1,1-diphenyl-2-picryldydrazyl radical and superoxide anion scavenging activity. In addition, the LMWHA-1 exhibited much stronger antioxidant activity than LMWHA-2 and HA. For antioxidant testing in vivo, LMWHA-1, LMWHA-2 and HA were orally administrated over a period of 7days in a cyclophosphamide(CY) induced immunosuppressed mice model. As results, administration of LMWHA was able to overcome CY-induced immunosuppression and significantly raised the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (TAOC) in immunosuppressed mice. The results showed that the LMWHA, possessing pronounced free radical scavenging and antioxidant activities.

Changes in some physicochemical properties and fatty acid composition of irradiated meatballs during storage

Meatball samples were irradiated using a (60)Co irradiation source (with the dose of 1, 3, 5 and 7 kGy) and stored (1, 2 and 3 weeks at 4°C) to appraise some physicochemical properties and the fatty acid composition. The physicochemical results showed no significant differences in moisture, protein, fat and ash content of meatballs because of irradiation. However, total acidity, peroxide and thiobarbituric acid (TBA) values increased significantly as a result of irradiation doses and storage period. The fatty acid profile in meatball samples changed with irradiation. While saturated fatty acids (C16:0, C17:0, C18:0, and C20:0) increased with irradiation, monounsaturated (C14:1, C15:1, C18:1, and C20:1) and polyunsaturated (C18:2, C18:3, and C22:2) fatty acids decreased with irradiation. Trans fatty acids (C16:1trans, C18:1trans, C18:2trans, C18:3trans) increased with increasing irradiation doses. Meatball samples irradiated at 7 kGy had the highest total trans fatty acid content. This research shows that some physicochemical properties and fatty acid composition of meatballs can be changed by gamma irradiation.

Spices as functional foods

Spices and aromatic herbs have been used since antiquity as preservatives, colorants, and flavor enhancers. Spices, which have long been the basis of traditional medicine in many countries, have also been the subject of study, particularly by the chemical, pharmaceutical, and food industries, because of their potential use for improving health. Both in vitro and in vivo studies have demonstrated how these substances act as antioxidants, digestive stimulants, and hypolipidemics and show antibacterial, anti-inflammatory, antiviral, and anticancerigenic activities. These beneficial physiological effects may also have possible preventative applications in a variety of pathologies. The aim of this review is to present an overview of the potential of spices and aromatic herbs as functional foods.

Effect of distillation waste water and plant hormones on spearmint growth and composition

BACKGROUND

Distillation waste water (DWW) is a by-product from steam distillation of essential-oil crops; and currently, it is discharged into streams and rivers. The effects of DWW from 13 essential-oil crops, extracts from two alkaloid-containing species, and three plant hormones (methyl jasmonate, MJ; gibberellic acid, GA3; and salicylic acid, SA) were evaluated on productivity, essential-oil content and composition of spearmint (Mentha spicata L.) cv. 'Native'.

RESULTS

Spearmint plant height was increased by the application of GA3 and Melissa officinalis DWW but suppressed by the application of Rosmarinus officinalis and Tagetes lucida DWW. Generally, MJ, GA3 and M. officinalis and Mentha arvensis DWW increased dry yields. The concentration of L-carvone in the oil ranged from 550 g kg(-1) (with Monarda citriodora DWW) to 670 g kg(-1) (with T. lucida DWW). M. citriodora DWW reduced the concentration of L-carvone in the oil by 23% relative to the control.

CONCLUSION

Results suggest that DWW from essential-oil crops may affect monoterpene synthesis in M. spicata and, hence, may have a direct effect on the essential oil composition. DWW from essential-oil crops may be used as a growth promoter and modifier of the essential oil composition of spearmint.

Microwave-assisted extraction of phenolic antioxidants from potato peels

A response surface method was used to optimize the microwave-assisted extraction parameters such as extraction time (t) (min), solvent (methanol) concentration (S) (v/v) and microwave power level (MP) for extraction of antioxidants from potato peels. Max. total phenolics content of 3.94 mg g⁻¹ dry weight (dw) was obtained at S of 67.33%, t of 15 min and a MP of 14.67%. For ascorbic acid (1.44 mg g⁻¹ dw), caffeic acid (1.33 mg g⁻¹ dw), ferulic acid (0.50 mg g⁻¹ dw) max contents were obtained at S of 100%, t of 15 min, and MP of 10%, while the max chlorogenic acid content (1.35 mg g⁻¹ dw) was obtained at S of 100%, t of 5 min, and MP of 10%. The radical scavenging activity of the extract was evaluated by using the DPPH assay and optimum antioxidant activity was obtained at S of 100%, t of 5 min, and MP of 10%.

Survival of human norovirus surrogates in milk, orange, and pomegranate juice, and juice blends at refrigeration (4 °C)

Fresh fruits, juices, and beverages have been implicated in human noroviral and hepatitis A virus outbreaks. The purpose of this study was to determine the survival of human norovirus surrogates (murine norovirus, MNV-1; feline calicivirus, FCV-F9; and bacteriophage MS2) in juices (orange and pomegranate juices), juice blends (pomegranate and orange juice) and milk over 0, 1, 2, 7, 14, and 21 days at refrigeration (4 °C). Juices, juice blends, and milk were inoculated with each virus over 21 days, serially diluted in cell culture media, and plaque assayed. MNV-1 showed no reduction in titer after 21 days in orange juice and milk, but moderate reduction (1.4 log) in pomegranate juice from a titer of 5 log(10) PFU/ml. However, MNV-1 was completely reduced after 7 days in the orange and pomegranate juice blend. FCV-F9 from a titer of 6 log(10) PFU/ml was completely reduced after 14 days in orange as well as pomegranate juice and by ∼ 3 logs after 21 days in milk at 4 °C. Interestingly, FCV-F9 was completely reduced after 1 day in the orange and pomegranate juice blend at 4 °C. MS2 was reduced by ∼ 1.28 log after 21 days in orange juice from a titer of 6 log(10) PFU/ml, and <1 log after 21 days in milk or pomegranate juice, with juice blends showing minimal reduction (<1 log) after 21 days at 4 °C. These results show the survival pattern of noroviruses that aid in the transmission of foodborne viral outbreaks. The data obtained can be used in quantitative viral risk assessment studies and to develop improved measures to prevent virus survival towards controlling outbreaks.

Evaluation of two natural extracts (Rosmarinus officinalis L. and Melissa officinalis L.) as antioxidants in cooked pork patties packed in MAP

Two natural extracts, from rosemary (Rosmarinus officinalis L.; Nutrox) and lemon balm (Melissa officinalis L.; Meliox) showing a potential antioxidant activity, have been evaluated and compared with a synthetic antioxidant (Butylated hydroxytoluene; BHT) and a control batch. Pork meat patties were made by addition of the mentioned compounds, cooked and packed in modified atmosphere and stored under illumination for 6 days. A descriptive sensory analysis was also conducted. The patties with natural extracts showed higher a*-values (P<0.001) than control and BHT samples. Cooked pork hardness was the lowest for Meliox batch after 0 and 3 days of storage in comparison with the rest of the batches. Nutrox batch showed the lowest TBARS values and hexanal content (P<0.05) throughout the storage period. The batches with natural antioxidants produced the highest concentrations of free thiol groups after 0 and 3 days. Differences in sensory attributes among batches were not detected by the judge panel.