Plant foods are rich in phenolic compounds (PCs) that display multifaceted bioactions in health promotion and disease prevention. To exert their bioactivity, they must be delivered to and absorbed in the gastrointestinal (GI) tract, transported in circulation, and reach the target tissues. During the journey from ingestion to target tissues and final excretion, PCs are subjected to modifications by many factors during their absorption, deposition, metabolism and excretion (ADME) and consequently their bioefficacy may be modified. Consistent with all nutrients in foods, PCs must first be released from the food matrix through mechanical, chemical, and enzymatic forces to facilitate absorption along the GI tract, particularly in the upper small intestine section. Further, glycosylation of PCs directs the route of their absorption with glycones being transported through active transportation and aglycones through passive diffusion. After enteral absorption, the majority of PCs are extensively transformed by the detoxification system in enterocytes and liver for excretion in bile, feces, and urine. The journey of PCs from consumption to excretion appears to be comparable to many synthetic medications, but with some dissimilarities in their fate and bioactivity after phase I and II metabolism. The overall bioavailability of PCs is determined mainly by chemical characteristics, bioaccessibility, and ADME. In this review, factors accounting for variation in PCs bioavailability are discussed because this information is crucial for validation of the health benefits of PCs and their mechanism of action.

In this research, total phenols, flavonoids, capsaicinoids, ascorbic acid, and antioxidant activity (ORAC, hydroxyl radical, DPPH, and TEAC assays) of fresh and processed (pickled and chipotle canned) Jalapeño and Serrano peppers were determined. All fresh and processed peppers contained capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, even though the latter could be quantified only in fresh peppers. Processed peppers contained lower amounts of phytochemicals and had lower antioxidant activity, compared to fresh peppers. Good correlations between total phenols and ascorbic acid with antioxidant activity were observed. Elimination of chlorophylls by silicic acid chromatography reduced the DPPH scavenging activity of the extracts, compared to crude extracts, confirming the antioxidant activity of chlorophylls present in Jalapeño and Serrano peppers.

The phenolic composition and antioxidant activity of pecan kernels and shells cultivated in three regions of the state of Chihuahua, Mexico, were analyzed. High concentrations of total extractable phenolics, flavonoids, and proanthocyanidins were found in kernels, and 5-20-fold higher concentrations were found in shells. Their concentrations were significantly affected by the growing region. Antioxidant activity was evaluated by ORAC, DPPH•, HO•, and ABTS•-- scavenging (TAC) methods. Antioxidant activity was strongly correlated with the concentrations of phenolic compounds. A strong correlation existed among the results obtained using these four methods. Five individual phenolic compounds were positively identified and quantified in kernels: ellagic, gallic, protocatechuic, and p-hydroxybenzoic acids and catechin. Only ellagic and gallic acids could be identified in shells. Seven phenolic compounds were tentatively identified in kernels by means of MS and UV spectral comparison, namely, protocatechuic aldehyde, (epi)gallocatechin, one gallic acid-glucose conjugate, three ellagic acid derivatives, and valoneic acid dilactone.

Anthocyanins (ACNs) are plant secondary metabolites from the flavonoid family. Red to blue fruits are major dietary sources of ACNs (up to 1 g/100 g FW), being cyanidin-3-O-glucoside (Cy3G) one of the most widely distributed. Cy3G confers a red hue to fruits, but its content in raspberries and strawberries is low. It has a good radical scavenging capacity (RSC) against superoxide but not hydroxyl radicals, and its oxidative potential is pH-dependent (58 mV/pH unit). After intake, Cy3G can be metabolized (phases I, II) by oral epithelial cells, absorbed by the gastric epithelium (1%-10%) and it is gut-transformed (phase II & microbial metabolism), reaching the bloodstream (<1%) and urine (about 0.02%) in low amounts. In humans and Caco-2 cells, Cy3G's major metabolites are protocatechuic acid and phloroglucinaldehyde which are also subjected to entero-hepatic recycling, although caffeic acid and peonidin-3-glucoside seem to be strictly produced in the large bowel and renal tissues. Solid evidence supports Cy3G's bioactivity as DNA-RSC, gastro protective, anti-inflammatory, anti-thrombotic chemo-preventive and as an epigenetic factor, exerting protection against Helicobacter pylori infection, age-related diseases, type 2 diabetes, cardiovascular disease, metabolic syndrome and oral cancer. Most relevant mechanisms include RSC, epigenetic action, competitive protein-binding and enzyme inhibition. These and other novel aspects on Cy3G's physical-chemistry, foodomics, and health effects are discussed.

The digestive enzymes–polyphenolic compounds (PCs) interactions behind the inhibition of these enzymes have not been completely studied. The existing studies have mainly analyzed polyphenolic extracts and reported inhibition percentages of catalytic activities determined by UV-Vis spectroscopy techniques. Recently, pure PCs and new methods such as isothermal titration calorimetry and circular dichroism have been applied to describe these interactions. The present review focuses on PCs structural characteristics behind the inhibition of digestive enzymes, and progress of the used methods. Some characteristics such as molecular weight, number and position of substitution, and glycosylation of flavonoids seem to be related to the inhibitory effect of PCs; also, this effect seems to be different for carbohydrate-hydrolyzing enzymes and proteases. The digestive enzyme–PCs molecular interactions have shown that non-covalent binding, mostly by van der Waals forces, hydrogen binding, hydrophobic binding, and other electrostatic forces regulate them. These interactions were mainly associated to non-competitive type inhibitions of the enzymatic activities. The present review emphasizes on the digestive enzymes such as α-glycosidase (AG), α-amylase (PA), lipase (PL), pepsin (PE), trypsin (TP), and chymotrypsin (CT). Existing studies conducted in vitro allow one to elucidate the characteristics of the structure–function relationships, where differences between the structures of PCs might be the reason for different in vivo effects.

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Dietary fiber and phenolic compounds are two recognized dietary factors responsible for potential effects on human health; therefore, they have been widely used to increase functionality of some foods. This paper focuses on showing the use of both substances as functional ingredients for enriching foods, and at the same time, describes the use of a single material that combines the properties of the two types of substances. The last part of the work describes some facts related to the interaction between dietary fiber and phenolic compounds, which could affect the bioaccessibility and absorption of phenolics in the gut. In this sense, the purpose of the present review is to compile and analyze evidence relating to the use of dietary fiber and phenolic compounds to enhance technological and nutritional properties of foods and hypothesize some of the possible effects in the gut after their ingestion.

Treatments to inhibit browning, decay and to extend shelf life of 'Keitt', 'Kent' and 'Ataulfo' mango cultivars as a fresh-cut produce were investigated. Combinations of calcium chloride (CaCl 2 ), antioxidants [ascorbic acid (AA), citric acid (CA)] and two commercial film coatings resulted in a reduction of browning and deterioration of fresh-cut mangoes stored at 5°C, especially for the Ataulfo cultivar. The use of CaCl 2 + AA + CA significantly reduced colour deterioration, loss of firmness and did not affect sensory characteristics of fresh-cut mango, with a larger effect in the Ataulfo cultivar. In general, these treatments prevented loss of sugar and vitamin C of cubes during storage at 5°C. Shelf life of this cultivar was 21 days, while that of Keitt and Kent was only 9 and 12 days, respectively. There is a correlation between carotene and vitamin C content of Ataulfo mango and its longer shelf life compared with the other cultivars.