Total Polyphenol Content in Food Samples and Nutraceuticals: Antioxidant Indices versus High Performance Liquid Chromatography

Recent advances in the analytical methods for quantitative determination of antioxidants in food matrices

Antioxidants are crucial in reducing oxidative stress and enhancing health, necessitating precise quantification in food matrices. Advanced techniques such as biosensors and nanosensors offer high sensitivity and specificity, enabling real-time monitoring and accurate antioxidant quantification in complex food systems. These technologies herald a new era in food analysis, improving food quality and safety through sophisticated detection methods. Their application facilitates comprehensive antioxidant profiling, driving innovation in food technology to meet the rising demand for nutritional optimization and food integrity. These are complemented by electrochemical techniques, spectroscopy, and chromatography. Electrochemical methods provide rapid response times, spectroscopy offers versatile chemical composition analysis, and chromatography excels in precise separation and quantification. Collectively, these methodologies establish a comprehensive framework for food analysis, essential for improving food quality, safety, and nutritional value. Future research should aim to refine these analytical methods, promising significant advancements in food and nutritional science.

In Vitro Biological Activities of Paederia grandidieri Leaf Extracts

In many developing countries, human health problems are solved using local plants. Knowledge of their chemical composition and biological activities can contribute to the creation of natural-based products usefully employed in human health. In this work, we analysed Paederia grandidieri leaves extracted with diverse eco-compatible procedures and subjected to chemical, microbiological, and cellular compatibility assays. Fresh leaves of P. grandidieri were harvested in southern Madagascar, where most of the population relies on P. grandidieri for daily dental care. Leaves were dried and powdered. Distilled water and ethanol at 25 °C and 60 °C from 6 to 24 h were used for extraction. Polyphenol composition, antioxidant activity, and antibacterial, prebiotic, and cytotoxic properties of the extracts were analysed. The aqueous extracts contained higher levels of flavan-3-ols and flavanones, while the hydro-alcoholic extracts were richer in flavonols and flavones. The aqueous extracts showed the highest total phenolic and total flavonoid contents, and antioxidant activity. The hydro-alcoholic extracts showed antibacterial effects against Listeria monocytogenes and Pseudomonas aeruginosa, two key foodborne and environmental pathogens, while the aqueous extracts showed prebiotic effects against Streptococcus salivarius. The cytotoxic effects of P. grandidieri leaf extracts were evaluated using the MTT assay on mouse fibroblasts (L929 cell line). The most cytotoxic extract was the aqueous extract at 25 °C. Given that P. grandidieri is routinely employed by the southern Madagascar population with healthy and strong teeth with fewer cases of tooth decay with respect to other regions, and in light of the significant chemical and microbiological properties, we maintain that P. grandidieri can be a suitable candidate for the production of pro-health products for the oral cavity. More in-depth studies will ensure a broader picture of the impact of extracts, especially for possible oral use.

Characterization of dark chocolates based on polyphenolic profiles and antioxidant activity

Dark chocolates were characterized according to geographical origin, cocoa variety, and cocoa content using the methylxanthine and polyphenolic composition and antioxidant activity as the data. The main study objective was to uncover sample patterns and identify possible markers of quality, variety, or origin to deal with authentication or fraud detection issues. In the study, a set of 26 dark chocolates from different varieties (e.g., Criollo, Forastero, and Trinitario) harvested in Africa, America, and Asia was analyzed. The optimized sample treatment consisted of defatting the chocolate (1 g of sample with 5 mL of cyclohexane for 15 min, three times) and then extracting the analytes by sonication with methanol/water 60:40 (v:v) for 15 min. The filtered extracts were analyzed by reversed-phase high-performance liquid chromatography with UV and spectrophotometric methods (Folin-Ciocalteu, ferric reducing antioxidant power, and aluminum methods) to determine individual phenolics and overall indexes of antioxidant and flavonoid content. Results from this chocolate set indicated that American samples are richer than African counterparts in alkaloids and phenolics (e.g., 1.7 vs. 1.1 mg g-1 caffeine and 14.5 vs. 12.5 mg g-1 total flavanols, respectively). Regarding cocoa varieties, Criollo cocoa was richer in bioactive compounds and antioxidant capacity (e.g., 16, 15, and 12 mg g-1 total flavanols for Criollo, Forastero, and Trinitario, respectively). These results indicate that the analytes resulted in potential descriptors of varietal or geographical attributes.

Dietary intake of polyphenols in adults and older adults residing in Chile: A population-based study

BACKGROUND: Polyphenols are a group of compounds distributed in foods of plant origin and have been considered as effective protective agents against chronic diseases. To date, there are limited data on polyphenol intakes worldwide. OBJECTIVE: The aim of the present study was to describe the intake of polyphenols and their subclasses in Chile based on data extracted from the National Food Consumption Survey 2010 –2012 (ENCA). METHODS: A total of 3658 participants were selected from whom information on food consumption frequency, anthropometric, clinical, socioeconomic and lifestyle variables were available. RESULTS: The mean intake value of total polyphenols was 979.5 + 695.5 mg/day. A higher intake was observed in men than in women. In addition, among adults, there is a higher consumption in the South macrozone. An increase in the intake of total polyphenols was evidenced when the population belonged to the high socioeconomic stratum, and the most consumed types were flavonoids and phenolic acids. CONCLUSION: Due to the growing evidence that shows a protective effect of polyphenol consumption, it is necessary to carry out more research related to the consumption of these compounds, promoting the consumption of foods that provide them and thus contributing to improve the current epidemiological.

Stability and Antioxidant Activity of Hydro-Glyceric Extracts Obtained from Different Grape Seed Varieties Incorporated in Cosmetic Creams

Grape seeds are agro-industrial by-products, which if improperly managed, may be responsible for socioeconomic and environmental problems. Nevertheless, it is possible to effectively valorize them by means of extraction of the bioactive compounds, especially the antioxidant phenolic molecules, using a safe, green, and environmentally-friendly extractive medium (i.e., hydro-glyceric solution). In the present study, the extraction was performed using seeds from two Lebanese varieties, Obeidi and Asswad Karech, and three international varieties, Marselan, Syrah, and Cabernet Franc. The type and amount of phenolic compounds were identified by High-Performance Liquid Chromatography (HPLC). Marselan was the extract richer in catechins (132.99 ± 9.81 μg/g of dried matter), and it also contained a higher amount of phenolic compounds (49.08 ± 0.03 mg of gallic acid equivalent/g of dry matter and 10.02 ± 0.24 mg of proanthocyanidin content/g of dry matter). The antioxidant capacity of the extracts was assessed using three different colorimetric assays including 2,2-DiPhenyl-1-PicrylHydrazyl (DPPH), CUPRIC ion Reducing Antioxidant Capacity (CUPRAC), and Ferric Reducing Antioxidant Power (FRAP). As expected, Marselan exhibited the highest antioxidant activity; as well, the total phenolic and proanthocyanidin content were the highest. The stability of the Marselan extract incorporated into a commercial cream, was performed at three different temperatures (4, 25, and 50 °C), and four different concentrations (5, 4, 3, 2%), over a period of 4 months, using different methods such as centrifugation, Heat-Shock Cycles, pH, and viscosity. All Marselan hydro-glyceric extract formulations were proven to be stable over the entire 4 months, where the highest stability was achieved at 4 °C and the least at 50 °C. This study supports the suitability of the incorporation of phenolic extracts into commercial creams to enrich the cosmetic industry with effective, natural, and safe skincare products.