Chemical profile and antioxidant potency of Citrus aurantium L. flower extracts with antibacterial effect against foodborne pathogens in rice pudding

Chemical characterization and discovery of novel quality markers in Citrus aurantium L. fruit from traditional cultivation areas in China using GC-MS-based cuticular waxes analysis

Citrus aurantium L. fruit is a commonly used Chinese medicine whose therapeutic effects tends to be affected by growing conditions. In order to gain insights into the effects of growing location on the cuticular wax composition of C. aurantium L. fruit, we analyzed the differences in the wax composition of its fruits collected from different regions. The findings showed that the cuticular waxes in the fruit peels were mainly composed of fatty acids, which differed quantitatively in the chemical profiles of C. aurantium L. samples from different geographical conditions. Particularly, the concentrations of linoleic acid and stearic acid in the total component content of the fruit peel were above 1%, with a greater level in the geo-authentic samples. Thus, GC-MS-based wax analysis was first used for the chemical characterization and quantification of cuticular waxes, which could be considered as a rapid way for evaluating the quality of medicinal fruits.

Evaluation of acute, subacute, and subchronic toxicity of a hepatoprotective herbal formulation

Background

The possible toxicity of natural products must be tested before being used in the market. The present work aimed to evaluate acute, subacute, and subchronic toxicity of an herbal formulation containing Anethum graveolens, Cynara scolymus, Citrus aurantium, Portulaca oleracea, and Silybum marianum.

Material and methods

Acute toxicity (2000 mg/kg, single dose) and sub-acute toxicity (600 and 1200 mg/kg/day, 4 weeks) tests were performed on female and male rats according to OECD 423 and OECD 407 guidelines, respectively. In the subchronic study (12 weeks), the animals were divided into three groups (6 females and 6 males per group): control, low-dose group (food supplemented with 300 mg/kg of the herbal product), and high-dose group (600 mg/kg).

Results

The herbal product at a single dose of 2000 mg/kg did not induce mortality for 14 days. In the sub-acute study, administration of the product for 28 days at 1200 mg/kg/day had no effect on survival, appetite (water and food consumption), body weight, serum biochemical parameters (BUN, creatinine, AST, ALT, ALP, bilirubin, albumin), histology of vital organs (liver, kidney, heart, brain), and hematological markers related to erythrocyte, platelet, and leukocyte. Similarly, in the subchronic study, the product did not induce mortality, change in histology of the vital organs, or alteration in hematological or biochemical parameters (except for an increase in ALP in female rats received 600 mg/kg).

Conclusion

The formulated product shows no signs of toxicity in rats up to 2000 mg/kg, 1200 mg/kg, and 600 mg/kg in acute, subacute, and subchronic phases, respectively. It is suggested to monitor ALP levels in females in case of long-term use of the product.

Assessing Listeria monocytogenes growth kinetics in rice pudding at different storage temperatures

Rice pudding is a popular artisanal dairy dessert highly consumed in the main rice-producing countries, including Egypt. This study aimed to evaluate and model the growth of Listeria monocytogenes in rice pudding dessert stored at different temperatures (4-25 °C) over its shelf-life. Lab-scale rice pudding samples were prepared following a traditional Egyptian recipe and inoculated with a three-strain cocktail of L. monocytogenes (ca. 3 × 102 cfu/g). Inoculated rice pudding samples (pH = 6.67 ± 0.06 and aw = 0.99 ± 0.002) were stored at different isothermal conditions (4, 8, 12, 18, and 25 °C) and microbiologically analysed for up to 30 days for pathogen quantification by plate count methodology. Global regression analysis was used to fit the Baranyi model coupled with the Ratkowsky model to growth data, relating L. monocytogenes concentrations (N, log cfu/g) with storage temperature (°C) and times (d). Model validation was performed using published independent data. L. monocytogenes growth potential increased by increasing storage temperature. The estimated Ratkowsky model parameters were b = 0.0819 ± 0.0017 log cfu/d·°C and Tmin = -3.28 ± 0.20 °C. The indices RMSE = 0.39 and R2adj = 0.97 indicated a good agreement between the experimental data and the model predictions. The estimated maximum growth rate (μmax) values ranged between 0.355 and 5.363 log cfu/d from 4 to 25 °C. The model was successfully validated using published L. monocytogenes Scott A and California strains growth data in rice pudding samples stored at 5, 12 and 22 °C, as evidenced by the assessed statistical indices. The predictive model developed and validated in this study will aid in decision-making regarding the microbiological safety of rice pudding dessert with respect to L. monocytogenes growth, considering a wide range of storage temperatures.

Citrus By-Products as a Valuable Source of Biologically Active Compounds with Promising Pharmaceutical, Biological and Biomedical Potential

Citrus fruits processing results in the generation of huge amounts of citrus by-products, mainly peels, pulp, membranes, and seeds. Although they represent a major concern from both economical and environmental aspects, it is very important to emphasize that these by-products contain a rich source of value-added bioactive compounds with a wide spectrum of applications in the food, cosmetic, and pharmaceutical industries. The primary aim of this review is to highlight the great potential of isolated phytochemicals and extracts of individual citrus by-products with bioactive properties (e.g., antitumor, antimicrobial, antiviral, antidiabetic, antioxidant, and other beneficial activities with health-promoting abilities) and their potential in pharmaceutical, biomedical, and biological applications. This review on citrus by-products contains the following parts: structural and chemical characteristics; the utilization of citrus by-products; bioactivities of the present waxes and carotenoids, essential oils, pectins, and phenolic compounds; and citrus by-product formulations with enhanced biocactivities. A summary of the recent developments in applying citrus by-products for the treatment of different diseases and the protection of human health is also provided, emphasizing innovative methods for bioaccessibility enhancements (e.g., extract/component encapsulation, synthesis of biomass-derived nanoparticles, nanocarriers, or biofilm preparation). Based on the representative phytochemical groups, an evaluation of the recent studies of the past six years (from 2018 to 2023) reporting specific biological and health-promoting activities of citrus-based by-products is also provided. Finally, this review discusses advanced and modern approaches in pharmaceutical/biological formulations and drug delivery (e.g., carbon precursors for the preparation of nanoparticles with promising antimicrobial activity, the production of fluorescent nanoparticles with potential application as antitumor agents, and in cellular imaging). The recent studies implementing nanotechnology in food science and biotechnology could bring about new insights into providing innovative solutions for new pharmaceutical and medical discoveries.

Edible Flowers: Antioxidant Compounds and Their Functional Properties

Edible flowers have been widely consumed for ages until now. The attractive colors and shapes, exotic aroma, and delightful taste make edible flowers very easy to attain. Moreover, they also provide health benefits for consumers due to the unique composition and concentration of antioxidant compounds in the matrices. Knowing the bioactive compounds and their functional properties from edible flowers is necessary to diversify the usage and reach broader consumers. Therefore, this reported review could be useful for functional product development, engaging the discussed edible flowers. We present a comprehensive review of edible flower composition and the functional properties of their antioxidant compounds, mainly phenolics.