Optimization of Ziziphora clinopodioides L. essential oil nanoencapsulation in chitosan nanocomplex by response surface methodology.

Nano-encapsulation of essential oils, a specific area of interest, can help overcome challenges associated with their commercial use. This study aimed to evaluate the effect of different concentrations of chitosan, Ziziphora clinopodioides L. essential oil (ZcEO), and Sodium-Tri Polyphosphate (TPP), both individually and in interaction, on several properties of EO-loaded chitosan nanoparticles. These properties include particle size (PS), zeta potential (ZP), and encapsulation efficiency (EE) using a two-stage emulsion-ionic gelation approach. The optimization of the parameters was done by response surface methodology using Box-Behnken design. The chemical composition of ZcEO was analyzed as well. The primary compounds in ZcEO were found to be pulegone (29.24 %), 1,3-dimethyl-2-(2-methylpropylidene) imidazolidine (9.05 %), piperitenone (6.65 %), thymol (5.38 %), and carvacrol (5.27 %). The PS ranged from 117.33 to 4934.1 nm, the ZP varied from -1.1 to -30.83 mV, and the EE spanned from 31.74 to 87.04 %. The results showed that an increase in the initial EO content led to a decrease in PS and ZP, but an increase in EE. Moreover, increasing the TPP concentration resulted in an enhancement in PS, ZP, and EE, whereas increasing the Chs concentration led to a slight increase in PS, ZP, and EE. Furthermore, the results of this study proved the interaction effect of different parameters on the responses investigated. Under optimized conditions, the optimal concentrations of chitosan, ZcEO and TPP were attained at 6.768, 6.078, and 7.595 mg/mL respectively. This resulted in a PS of 117.331 nm, a ZP of -20.949 mV, and an EE of 75.385 %. In conclusion, the results suggest that adjusting the concentrations of Chs, EO, and TPP is an effective approach to controlling the properties of NPs and optimizing their performance.

Development of Antibacterial Biocomposites Based on Poly(lactic acid) with Spice Essential Oil (Pimpinella anisum) for Food Applications.

Among the main biodegradable food packaging materials, poly-lactic acid (PLA) is a commercially successful polymer used notably in the food packaging industry. In this study, active PLA films containing different percentage of anise essential oil (AE) (0, 0.5, 1 and 1.5% v/v) were developed, and characterized by physical, mechanical and antibacterial analysis. Based on physical examinations, thermal stability of PLA/AE films was greater than the neat PLA film, and the minimum water vapor permeability (WVP) was recorded for PLA/0.5AE film (1.29 × 10 11 g/m s), while maximum WVP was observed for PLA/1.5AE (2.09 × 1011 g/m s). Moreover, the lightness and yellowness of the composites were decreased by the addition of AE. For the PLA composites with 1.5% AE, the tensile strength decreased by 35% and the elongation break increased by 28.09%, comparing to the pure PLA. According to the antibacterial analysis, the minimum inhibitory concentrations of PLA/AE film were 5 to 100 mg/mL and the active composite could create visible inhibition zones of 14.2 to 19.2 mm. Furthermore, the films containing AE inhibited L. monocytogenes and V. parahaemolyticus in a concentration-dependent manner. The confirmation of the success of the incorporation of EOs into the PLA films was further evaluated using principal component analysis, where positive results were obtained. In this context, our findings suggest the significant potency of AE to be used as an antibacterial agent in active food packaging.

Aflatoxin M1 in raw, pasteurized and UHT milk marketed in Iran.

Aflatoxin M1 (AFM1) is a 2B Group human carcinogens agent and introduces into the human diet by milk consumption. In the present study 257 raw, 143 pasteurized and 61 UHT milk samples were collected from markets in 117 cities throughout Iran, during winter 2017 and AFM1 contents were determined using a HPLC-FLD method after immunoaffinity clean-up. Mean recovery rates and relative standard deviations of the method were 90.6 ± 5.7%. AFM1 was detected in 252 of 461 (54.7%) samples (mean 31.3 ± 8.8 ng/L), ranging from <10 to 150 ng/L. Three samples (0.6%) exceeded the Iranian maximum limit of 100 ng/L. The mean AFM1 content was significantly higher in raw milk samples obtained from humid climate areas. The extrapolated concentration of AFB1 in dairy cattle feed based on the AFM1 value of milk was 1.96 µg/kg. The AFM1 contamination of milk seems not to be a serious public health concern in Iran.

Exposure to Aflatoxin M1 through Milk Consumption in Tehran Population, Iran.

Milk would be contaminated with Aflatoxin M1 (AFM1), if it was obtained from lactating animal which fed with feedstuffs containing Aflatoxin B1 (AFB1). AFM1 is classified as group 2B, possibly carcinogenic to humans and its exposure to AFM1 through milk consumption is a public concern. The purpose of this study was to determine the AFM1 exposure through liquid milk consumption for adult consumers in Tehran. Forty-five samples including raw, pasteurized, and UHT milk samples were collected from markets in different cities of Tehran province in January and February 2017. The AFM1 was determined by HPLC method after immunoaffinity column clean up. Also, the milk intake was calculated using household budget survey. Finally, the daily intake of AFM1 through milk consumption was estimated using a deterministic approach. From total 45 samples, AFM1 was detected in 36 (80%) samples, although none of the analyzed samples were exceeded Iran legal limit of 0.1 µg/kg. On the basis of the average milk intake, the mean daily exposure to AFM1 was estimated between 0.03 ng/ Kg BW per day (lower bound estimate) and 0.06 ng/ Kg BW per day (upper bound estimate) and the 95th percentile daily exposure was calculated at 0.14 ng/ Kg BW per day. According to these values, it should be expected that the adults of Tehran population are not exposed to a significant risk of Hepatocarcinoma associated with AFM1 intake through milk consumption.

Effect of Zataria multiflora Boiss. essential oil, nisin, and their combination on the production of enterotoxin C and alpha-hemolysin by Staphylococcus aureus.

The effect of different concentrations of Zataria multiflora Boiss. essential oil (EO; 0%, 0.005%, and 0.015%), nisin (0, 0.125, and 0.25 microL/mL), and their combinations on the production of staphylococcal enterotoxin C (SEC) and alpha-hemolysin (alpha-toxin) by Staphylococcus aureus at different inoculation levels (10(3), 10(4), and 10(5) cfu/mL) in brain heart infusion broth during storage at 35 degrees C for up to 43 days was evaluated. The SEC production was significantly (p < 0.05) inhibited and the hemolysis due to alpha-toxin was significantly (p < 0.05) reduced by EO concentration at levels 0.015% and 0.005%, respectively. Significant (p < 0.05) inhibitory effect of EO on SEC production at level 0.005% was observed when it was used in combination with nisin = 0.125 microL/mL. The significant (p < 0.05) synergistic effect of EO = 0.005% and nisin = 0.125 microL/mL was also observed as more reduction of hemolysis due to alpha-toxin than EO = 0.005% alone. Further, EO significantly (p < 0.05) prevented SEC production by S. aureus during the manufacturing process of a traditional Iranian white brined cheese (as a food model) even at its lowest concentration (5 microL/100 mL), in this study.