Encapsulation of grape seed oil in oil-in-water emulsion using multilayer technology: Investigation of physical stability, physicochemical and oxidative properties of emulsions under the influence of the number of layers.

Many studies have shown that grape seed oil (GSO) is one of the vegetable fats that are plentiful in essential fatty acids and can be used as a fat substitute or to modify fat in food products to reduce saturated fatty acids. However, due to its low solubility and high sensitivity to oxidation, it is necessary to develop delivery systems that can distribute GSO in food more effectively. Recently, the preparation of emulsions using the layer-by-layer (LBL) method has many advantages in delivering lipid-soluble functional compounds. This research was used to check the formation of GSO oil-loaded primary, secondary and tertiary multilayer emulsions stabilized by mixture of anionic gelatin, cationic chitosan, and anionic basil seed gum (BSG) as the aqueous phase at pH 5, prepared using a layer-by-layer electrostatic deposition technique. Multilayer emulsions prepared by GSO and a mixture of gelatin, chitosan, and BSG as the aqueous phase at pH 5. Finally, the effect of the number of layers on the physicochemical properties (particle size, viscosity, turbidity, refractive index, and physical stability) and oxidative stability (peroxide value, thiobarbituric acid value, and fatty acid profile) during the storage time (30 days) at two temperatures 25 °C & 4 °C was investigated. Also, the zeta potential and Fourier transform infrared spectroscopy (FTIR) of mono-layer and multi-layer emulsions were investigated. The results revealed that by increasing the number of layers of multi-layer emulsion of GSO, the stability has improved. Thus, the tertiary emulsion has been more effective than the other two emulsions in maintaining the physicochemical characteristics and stability over time (P < 0.001). Morphological characterization and FTIR spectroscopy results confirmed that gelatin, chitosan, and BSG were successfully loaded into the LBL emulsions. This study can improve the original percept of multilayer emulsions and promulgate their potential applications for the entire encapsulation of essential fatty acids to enrich and prevent peroxide attack.

High biofilm-forming Pseudomonas strains isolated from poultry slaughterhouse surfaces: Their importance in the persistence of Salmonella enteritidis in slaughterhouses.

The surfaces of poultry slaughterhouse equipment are significant sources of contamination with Pseudomonas strains, which leads to spoilage of poultry meat during subsequent refrigerated storage. In this study, Pseudomonas strains with high biofilm-forming ability were isolated from different surfaces of the poultry slaughterhouse equipment, identified based on molecular data, and characterized their biofilm-forming ability. After 24 h of incubation at 25 °C, 54 out of 58 Pseudomonas strains produced biofilm in vitro on polystyrene microplates. Seven isolates with high-ability to produce biofilm were identified as P. fragi (three strains), P. fluorescens (two strains), P. lundensis and P. cedrina. Despite their differences, these strains produced high amounts of biofilm in pure- and dual-species cultures with S. enteritidis on stainless steel surfaces. However, their ability to produce dual-species biofilms with S. enteritidis depends on whether S. enteritidis form the biofilm simultaneously with the Pseudomonas strains or whether Pseudomonas strains have already formed a biofilm. In concurrent inoculation, S. enteritidis participated in biofilm formation with all seven Pseudomonas strains with varying percent contributions. However, in delayed inoculation, S. enteritidis did not contribute in the biofilm formed by P. lundensis R26, P. fragi R39, and P. fluorescens R47. In addition to highlighting the complexity of bacterial interactions associated with Pseudomonas strains, these results showed that Pseudomonas strains can be implicated in Salmonella persistence in poultry slaughterhouses.

Electrospun chia seed mucilage/PVA encapsulated with green cardamonmum essential oils: Antioxidant and antibacterial property.

In this work, the potential of chia seed mucilage (CSM) as a new source of carbohydrate for encapsulation of green cardamonmum Essential oils (GCEOs) was evaluated. 1H NMR spectrum, FTIR spectrum and, SEM image has confirmed the existence of the GCEOs in the nanofibers. The nanofibers of CSM and polyvinyl alcohol have not antibacterial property, while nanofibers containing GCEOs show antibacterial activity against E. coli and S. aureus. Incorporating GCEOs in CSM nanofibers improved the antioxidant of the generated nanofibers. The amount of radical scavenging for the nanofibers containing 16 (mg/ml) of GCEOs was 18% and increasing the GCEOs concentration up to 64 (mg/ml) leads to grow the activity up to 41%. Thus, our studies indicate that nanofiber can be used as a novel antioxidant and antibacterial agent in the food and pharmaceutical industry.

Biological reduction of aflatoxin B1 in yogurt by probiotic strains of Lactobacillus acidophilus and Lactobacillus rhamnosus.

The present study was conducted to investigate the ability of two probiotic strains, L. acidophilus PTCC 1643 and L. rhamnosus PTCC 1637, to bind aflatoxin B1 (AFB1, 20 ng/ml) in comparison with yogurt starter cultures, at equal bacterial count (~ 109 LogCFU/ml) during a 21-day storage period at 4 °C. All assessed treatments exhibited high percentages of AFB1-binding, ranged from 64.56 to 96.58%. However, the ability of probiotic bacteria was statistically higher than yogurt starter cultures. Aflatoxin binding ability of the selected lactic acid bacteria was dependent on both time and bacteria species. The highest and the lowest percentages of AFB1-removal was observed at 11th day of cold storage by L. rhamnosus (96.58 ± 3.97%) and at the first day of storage for yogurt starter cultures (64.56 ± 5.32%), respectively. The stability of bacterial cells-AFB1 complex was remarkable, since only 0.84-26.75% of bounded AFB1 was released from bacterial cells after 3 times washing during the storage period.

Effect of thermal treatment on physicochemical and antioxidant properties of honey.

Industrial treatments of commercial honeys during extraction and storage affect the quality of honey. One of the most common treatments in the honey industry is thermal treatment which could make some changes in the physicochemical and antioxidant properties of honey. This study was conducted to determine the effect of thermal treatment at 63 °C for 10, 20 and 30 min on physicochemical and antioxidant properties of lotus, thyme, and multifloral honeys. Samples were analyzed for pH, free acidity, moisture, hydroxymethylfurfural (HMF), color, total phenolic content, DPPH° radical-scavenging activity and ferric reducing antioxidant power (FRAP). Changes were more or less observed in all the physicochemical characteristics of honeys during the thermal treatment. However, among the physicochemical characteristics, increase in HMF content and decrease in total phenolic contents were more evident. Considering the antioxidant capacity of honeys, decreases in DPPH° radical scavenging activity of thyme honeys and FRAP values of thyme and lotus honeys during the thermal treatment were observed. Changes made in physicochemical characteristics of honeys during the thermal treatment are merely important from the standpoint of compliance with national and international legal limits. However, from the nutritional point of view, decrease in the antioxidant capacity of honeys is of particular importance and may affect the nutritional and health benefits of honey.

Effect of the bacterial growth phase and coculture conditions on the interaction of Acanthamoeba castellanii with Shigella dysenteriae, Shigella flexneri, and Shigella sonnei.

Shigella species and Acanthamoeba castellanii share the same ecological niches, and their interaction has been addressed in a limited number of research. However, there are still uncertain aspects and discrepant findings of this interaction. In the present study, the effects of the bacterial growth phase, cocultivation temperature and the type of culture media on the interaction of A. castellanii with Shigella dysenteriae, Shigella sonnei and Shigella flexneri were evaluated. In nutrient-poor page's amoeba saline (PAS) medium, the number of recovered bacteria and the uptake rates were significantly higher in stationary phase cells than logarithmic phase cells. However, no significant differences were observed in the number of recovered bacteria and the uptake rates between logarithmic and stationary phase cells in nutrient-rich peptone-yeast extract-glucose (PYG) medium. While the number of recovered bacteria was significantly higher in nutrient-rich than nutrient-poor media, in all the three Shigella species, the bacterial uptake rates were significantly higher in nutrient-poor than nutrient-rich media at both cocultivation temperatures. In both nutrient-poor and nutrient-rich media and at both cocultivation temperatures, the number of viable Shigella species after 24 h incubation were not influenced by the presence of A. castellanii. Although Shigella species did not proliferate in A. castellanii trophozoites, a considerable number of bacteria were survived in the trophozoites up to 15 days. From the public health perspective, the results of this study are important for further understanding of the nature of the interaction of these organisms and to deal with Shigella species in the environment.

Effects of Echinacea purpurea on Hepatic and Renal Toxicity Induced by Diethylnitrosamine in Rats.

BACKGROUND: Nitrites are mainly used in food preservation. These materials could change to nitrosamine due to the effect of heat and gastric acid. Nitrosamine is absorbed in intestine and enters the liver and hepatocytes by portal venous system, and hampers the detoxification system of liver by interfering in cytochrome P450 enzymes, so, the liver gently proceeds to cirrhosis and cancer. OBJECTIVES: The current study aimed to investigate the hepatic and renal protective effects of aerial parts of Echinacea purpurea extract (EPE) on injury induced by diethylnitrosamine (DEN). MATERIALS AND METHODS: Twenty Wistar rats were divided into 4 groups. Groups were as follow: Control group (normal saline), DEN (200 mg/kg, IP, a single dose), EPE (100 mg/kg, orally, daily) and DEN + EPE which received as group DEN and EPE. After 30 days, Blood samples, and liver and kidney tissues were taken for further examination. Aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), BUN, Creatinine and total and direct bilirubin were estimated in serum. RESULTS: DEN induced hepatotoxicity and nephrotoxicity in all the treated animals by elevated serum ALT, AST, ALP and BUN, creatinin and total and direct bilirubin levels. AST, BUN and total and direct bilirubin significantly decreased in DEN + EPE compared to DEN group. After 30 days of DEN administration, histopathological investigation revealed proliferation of hepatic stellate cells and early fibrosis which were partly improved by EPE administration. CONCLUSIONS: The current study findings indicated that Echinacea purpurea extract played an important role in the protection against DEN toxicity in rats.