Black bean (Phaseolus vulgaris L. cv. "Tolosa") polyphenolic composition through cooking and in vitro digestion.

In this study, five different black bean (Phaseolus vulgaris L. cv. Tolosa) populations cultivated in different geographical areas including Oiartzun, Andoain, Azkoitia, San Esteban and Amasa Villabona, were studied and their polyphenolic content was determined. Two food products were prepared from the five different bean populations, cooked "Tolosa" beans and a hummus made with "Tolosa" cooked beans. Moreover, the variations of total polyphenol content (TPC), total anthocyanin content (TAC) and free radical scavenging activity by the 1,1-diphenyl-1-picrylhydrazyl (DPPH) method were analyzed for raw beans, cooked beans, and "Tolosa" beans hummus. Polyphenolic detailed composition was determined by means of HPLC-MS-QTOF analysis. The "Tolosa" bean population richest in polyphenols was selected in order to study the effect of in vitro digestion on the polyphenolic content and antioxidant effect and the degradation of the main anthocyanins was followed during the in vitro digestion. Finally, the effect of the different phases of digestion on the cytotoxicity in Caco-2 cells was determined. The results suggest that cooking "Tolosa" black beans results in an increase in the bioaccessibility of polyphenols and their antioxidant activity, which, additionally has a positive effect on Caco-2 intestinal cell viability.

Study on the phenolic composition and antioxidant properties of white-, yellow-, and black-corn (Zea mays L.) foodstuffs.

BACKGROUND: Black corn possesses potent antioxidants, but these are mostly lost during processing. In this study we evaluated the antioxidant content of two different black ('Millo Corvo') corn-based products (i.e. tortillas and cookies) subject to moderate processing. A parallel study on white and yellow corns was carried out for comparison. RESULTS: Raw 'Millo Corvo' flour exhibited higher contents of phenolic acids, flavonoids, and particularly anthocyanins than white and yellow flours did. Phenolic acids decreased in cookies but did not in tortillas; flavonoids did not exhibit a clear tendency, and anthocyanins were always preserved. Antioxidant activity (AA) obtained for 'Millo Corvo' samples was twice as high as the value measured in white and yellow corns in terms of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. The difference in AA was even more remarkable in terms of photochemiluminiscence antiradical activity. The conditions used during the cookie-making process enabled the natural antioxidant characteristics of 'Millo Corvo' to be preserved. However, the conditions applied to prepare tortillas resulted in major losses. CONCLUSIONS: The initial phenolics, in particular anthocyanins, and AA of 'Millo Corvo' flour can be maintained during processing as long as the conditions applied are 183 °C for 20 min in the absence of a high water content. Millo corvo products possess improved antioxidant characteristics compared with those from white and yellow corns. Millo corvo is a promising black corn type to prepare health-promoting corn-based foodstuffs. © 2023 Society of Chemical Industry.

Varietal Effect on Composition and Digestibility of Seedless Table Grapes (Vitis vinifera L.) under In Vitro Conditions.

Grapes are one of the richest sources of polyphenols in the Mediterranean diet and, therefore, a very good source of antioxidants in the human diet. For practical reasons, in recent years the market for seedless grape varieties has grown exponentially. These varieties are not well characterized yet, and therefore it is necessary to study the changes in composition that these new varieties bring in. Likewise, the effect of digestion on the bioavailability of polyphenols in foods of plant origin is well known, which, consequently, will also affect antioxidant activity and, in general, bioactivity. In this work, we studied the effect of the grape variety on the initial grape composition and on the absorbable fraction, as it would reach the intestine after in vitro digestion. Our results showed that black and red varieties have great potential for increasing the antioxidant content of the diet. Additionally, we have concluded that all polyphenols, with the exception of flavanols, see their bioavailable fraction diminished under in vitro conditions.

Enrichment of Olive Fruits in Antioxidant Content by Pre-Harvest Salicylic Acid Treatment.

We here study the effect of the pre-harvest application of salicylic acid at two different concentrations on the olive phenolic composition. Influence of the cultivar and harvesting day were considered. As a result, the total phenol content increased significantly, particularly when using 200 mg mL-1 of salicylic acid. However, the free radical scavenging activity was cultivar dependent. For instance, when the olives were harvested on day 3 and treated with 200 mg mL-1 of salicylic acid, the antioxidant activity decreased from 161 to 278 µg mL-1 for Arbequina, whereas it increased from 397 to 258 µg mL-1 for Picual. Generally speaking, oleuropein and hydroxytyrosol contents enhanced with the application of 200 mg mL-1 of salicylic acid. The results found suggest that exogenous salicylic acid is an interesting agronomic practice to enrich olive fruits in antioxidants.

Exogenous Salicylic Acid Improves Phenolic Content and Antioxidant Activity in Table Grapes.

Grapes contain high contents of phenolics, which are known to possess health promoting properties. Exogenous application of phytoregulators, mainly methyl jasmonate and abscisic acid, to grapevines to enhance phenolic content has been reported (Portu et al. Sci Hortic 240: 378-386, 2018; Ranjbaran et al. J Faculty Agric Kyushu Univ 56: 263-267, 2011). However, these phytohormones possess some drawbacks that can be overcome by using other phytoregulators as an alternative. In this work the effect of an additional phytohormone, salicylic acid, to grapevines on the phenolics and antioxidant activity of grapes was investigated. To our knowledge, salicylic acid has been earlier applied to grapevines to affect grape ripening and quality (Lóay. Egyptian J Basic Applied Sci 4: 227-230, 2017). However, this is the first time it is applied to increase the total phenolic content. As a result of our study, total phenol content and the free radical scavenging activity increased with 100 mg l-1 of salicylic acid. In particular, the total phenol content increased from 768.3 to 1843.5 mg 100 g-1 and the IC50 values decreased from 45.2 to 13.2 mg ml-1. Also the contents of individual phenolics mostly increased significantly with 100 mg l-1 of salicylic acid, except anthocyanins. Higher concentrations of salicylic acid (ie, 500 mg l-1vs 100 mg l-1) did not result in higher contents of phenolics. Therefore, 100 mg l-1 was selected as the best salicylic acid concentration to be used in the treatment. The application of exogenous salicylic acid to grapevines is an interesting agronomic practice to obtain table grapes with improved health-promoting properties.

Supercritical fluid extraction of grape seeds: extract chemical composition, antioxidant activity and inhibition of nitrite production in LPS-stimulated Raw 264.7 cells.

Grape by-products are a rich source of bioactive compounds having broad medicinal properties, but are usually wasted from juice/wine processing industries. The present study investigates the use of supercritical fluid extraction (SFE) for obtaining an extract rich in bioactive compounds. First, some variables involved in the extraction were applied. SFE conditions were selected based on the oil mass yield, fatty acid profile and total phenolic composition. As a result, 40 °C and 300 bar were selected as operational conditions. The phenolic composition of the grape seed oil was determined using LC-DAD. The antioxidant activity was determined by ABTS and DPPH assays. For the anti-inflammatory activity the inhibition of nitrite production was assessed. The grape seed oil extracted was rich in phenolic compounds and fatty acids with significant antioxidant and anti-inflammatory activities. From these results, added economic value to this agroindustrial residue is proposed using environmentally friendly techniques.

A new approach based on off-line coupling of high-performance liquid chromatography with gas chromatography-mass spectrometry to determine acrylamide in coffee brew.

A new method based on off-line coupling of LC with GC in replacement of conventional sample preparation techniques is proposed to analyze acrylamide in coffee brews. The method involves the preseparation of the sample by LC, the collection of the selected fraction, its concentration under nitrogen, and subsequent analysis by GC coupled with MS. The composition of the LC mobile phase and the flow rate were studied to select those conditions that allowed separation of acrylamide without coeluting compounds. Under the conditions selected recoveries close to 100% were achieved while LODs and LOQs equal to 5 and 10 µg/L for acrylamide in brewed coffee were obtained. The method developed enabled the reliable detection of acrylamide in spiked coffee beverage samples without further clean-up steps or sample manipulation.

Evaluation of pesticide residue contents in fruit juice by solid-phase microextraction and multidimensional gas chromatography coupled with mass spectrometry.

A new method based on the use of SPME followed by the MDGC-MS analysis was developed to determine pesticides in fruit juice. Different pesticide mixture standards (i.e. Mix 101, 13 and 164) were initially analyzed to optimize the separation conditions. To evaluate the advantages of the two-dimensional system over monodimensional GC, a comparative study on relative standard deviations, detection limits and correlation coefficients was carried out. As a result, selective transfers of some pesticides from the first to the second dimension were at times essential to avoid overlapping. The selected separation conditions from the study with standards were applied to fruit juices spiked with some pesticide standards. The results found in this work prove that the employment of a multidimensional analysis technique permits to avoid false positives obtained frequently on monodimensional techniques as a consequence of interferences of the analytes with matrix components.

Development of a method based on on-line reversed phase liquid chromatography and gas chromatography coupled by means of an adsorption-desorption interface for the analysis of selected chiral volatile compounds in methyl jasmonate treated strawberries.

A method based on the use of the through oven transfer adsorption-desorption (TOTAD) interface in on-line coupling between reversed phase liquid chromatography and gas chromatography (RPLC-GC) for the determination of chiral volatile compounds was developed. In particular, the method was applied to the study of the influence of methyl jasmonate (MJ) treatment on the production and enantiomeric composition of selected aroma compounds in strawberry. The compounds studied were ethyl 2-methylbutanoate, linalool and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (i.e. furaneol), which were examined on days 3, 6 and 9 after treatment. The method developed resulted in relative standard deviations (RSDs) of 21.6%, 8.1% and 9.8% and limits of detection (LD) of 0.04, 0.07 and 0.02mg/l for ethyl 2-methylbutanoate, linalool and furaneol, respectively. The application of the RPLC-TOTAD-GC method allowed higher levels of ethyl 2-methylbutanoate, linalool and furaneol to be detected, particularly after 9 days of treatment. Besides, MJ demonstrated to affect the enantiomeric distribution of ethyl 2-methylbutanoate. On the contrary, the enantiomeric composition of linalool and furaneol kept constant in both control and MJ-treated strawberries throughout the study. These results are discussed.

Polydimethylsiloxane as a packing material in a programmed temperature vaporizer to introduce large-volume samples in capillary gas chromatography.

The viability of using polydimethylsiloxane (PDMS) as a retaining material inside a programmed temperature vaporizer injector for the introduction of large-volume samples in gas chromatography is assessed. To that end, materials made up of Volaspher A-2 and coated with different percentages of PDMS (5%, 15%, and 50%) are considered. In addition, adsorbent (Tenax TA) and absorbent (PDMS) materials are comparatively studied in terms of their retention capacity. A relative standard deviation lower than 5.0% is obtained from the injection of PDMS, whereas values up to 49% are provided by Tenax TA. Significantly higher amounts of different volatile compounds are retained by PDMS in comparison with Tenax TA. In conclusion, the use of PDMS as a packing material seems to be viable for large-volume sampling and particularly recommendable for minor compounds occurring in complex matrices.

Semipreparative-scale gas-chromatographic separation of filbertone enantiomers.

The enantioselectivity of heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl-beta-CD) toward racemic filbertone (E-5-methyl-hep-2-en-4-one) was studied by performing the chiral separation on a capillary column, a thick-film wide-bore column and a semipreparative column. The semipreparative enantioseparation of filbertone was achieved at 80 degrees C by using a packed column providing (R)- and (S)-enantiomers of filbertone with ee 90 and 96%, respectively. The isolated enantiomers (approximately 250 microg each, ee = 90-96%) may be used for studies on the relationship of chirality and biological activity by olfactory screening and toxicological studies.