The Application of Ultrasound and Enzymes Could Be Promising Tools for Recovering Polyphenols during the Aging on Lees Process in Red Winemaking

The final concentration of phenolic compounds in wines is usually lower than what might be expected, given their concentration in grapes. This is in part due to the interactions between cell walls from grapes and yeast with phenolics during red winemaking. Most of these aggregates are insoluble and end up precipitating, forming part of the lees. The objective of this study is to determine the capacity of ultrasounds and/or enzymes treatments (β-glucanase and a pectolytic enzyme) to release the anthocyanins and tannins adsorbed in the lees. The ultrasound (US) applied for 120 min slightly favored the extraction of anthocyanins and doubled tannin extraction. Shorter sonication times did not show any positive effect. The combination of β-glucanase and pectolytic enzyme was always more effective in the liberation of anthocyanins (both no-acylated and acylated anthocyanins) and tannins than the enzymes acting separately. The combination of US (120 min), β-glucanase and pectolytic enzyme showed an additive effect, increasing the extraction of phenolic compounds with respect to the individual treatments and also releasing a large quantity of low molecular weight polysaccharides, compounds of enological importance. These results of this study could be of enological interest, facilitating and accelerating the aging on lees process, through the liberation of polysaccharides and the recovery of the phenolic compounds lost during vinification.

The Genetic Basis of Anthocyanin Acylation in North American Grapes (Vitis spp.)

Hydroxycinnamylated anthocyanins (or simply ‘acylated anthocyanins’) increase color stability in grape products, such as wine. Several genes that are relevant for anthocyanin acylation in grapes have been previously described; however, control of the degree of acylation in grapes is complicated by the lack of genetic markers quantitatively associated with this trait. To characterize the genetic basis of anthocyanin acylation in grapevine, we analyzed the acylation ratio in two closely related biparental families, Vitis rupestris B38 × ‘Horizon’ and ‘Horizon’ × Illinois 547-1, for 2 and 3 years, respectively. The acylation ratio followed a bimodal and skewed distribution in both families, with repeatability estimates larger than 0.84. Quantitative trait locus (QTL) mapping with amplicon-based markers (rhAmpSeq) identified a strong QTL from ‘Horizon’ on chromosome 3, near 15.85 Mb in both families and across years, explaining up to 85.2% of the phenotypic variance. Multiple candidate genes were identified in the 14.85–17.95 Mb interval, in particular, three copies of a gene encoding an acetyl-CoA-benzylalcohol acetyltransferase-like protein within the two most strongly associated markers. Additional population-specific QTLs were found in chromosomes 9, 10, 15, and 16; however, no candidate genes were described. The rhAmpSeq markers reported here, which were previously shown to be highly transferable among the Vitis genus, could be immediately implemented in current grapevine breeding efforts to control the degree of anthocyanin acylation and improve the quality of grapes and their products.

Identification of Five Acylated Anthocyanins and Determination of Antioxidant Contents of Total Extracts of a Purple-Fleshed Ipomoea batatas L. Variety Grown in Burkina Faso

Anthocyanins are bioactive compounds, which thanks to their anti-free radical properties, can protect the human body against oxidative stress. The latter can cause many diseases, such as cancer, aging. The extract of the green cap purple variety of the sweet potato (Ipomoea batatas L.) is active against the radical ABTS. Its antioxidant content is estimated at 0.183 mg E TEAC/ g fresh material. The characterization of anthocyanins was performed by high performance liquid chromatography-mass spectrometry-UV (HPLC-MS-UV) and high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) analyses. These analyses allowed the identification of five anthocyanic compounds. These are: cyanidin 3-(6''-caffeoyl- 6'''-p-hydroxybenzoyl sophoroside) -5-glucoside; cyanidin 3-(6''-feruloyl 6'''-caffeoyl sophoroside) -5-glucoside; peonidin 3-(6'''-caffeoyl sophoroside)-5-glucoside; peonidin 3-(6''-caffeoyl-6'''-p-hydroxybenzoyl sophoroside) -5-glucoside; and peonidin 3-(6''-feruloyl -6'''-caffeoyl sophoroside)-5-glucoside.

Characterization of Anthocyanins From Intraspecific Crosses of Monastrell With Other Premium Varieties

One way in which the wine sector is reacting to the challenge of climate change is to develop plant material that is adapted to the new conditions. Such a strategy will allow the continuation of quality viticulture in traditional winemaking areas that will otherwise be abandoned. The objective of this study was to characterize the anthocyanin composition and content of selected intraspecific hybrids of Monastrell with two other varieties (Syrah and Cabernet Sauvignon). The experiment was carried out over three successive seasons, and the polyphenolic quality of the grapes and wines was assessed along with the adaptation of the hybrids to the high temperatures which will inevitably affect our area (south-eastern Spain). The results showed that, compared with grapes of the Monastrell variety and the wines made from them, most of the hybrids (MS10, MS34, and MC111) had a higher total anthocyanin concentration and overall content of acylated anthocyanins, depending on the year studied.

Polyacylated Anthocyanins in Bluish-Purple Petals of Chinese Bellflower, Platycodon grandiflorum

The bluish-purple petals of Chinese bellflower, Platycodon grandiflorum (kikyo in Japanese), contain platyconin (1) as the major anthocyanin. Platyconin (1) is a polyacylated anthocyanin with two caffeoyl residues at the 7-position, and its color is stable in a diluted, weakly acidic aqueous solutions. HPLC analysis of the fresh petal extract showed the presence of several minor pigments. Photo-diode array detection of minor pigments suggested that some of these were polyacylated anthocyanins. To establish the relationship between structure and stability of the acylated anthocyanins and to obtain information on their biosynthetic pathways, minor pigments were isolated from the petals, and their structures were determined by MS and NMR analyses. Four known (2–5) and three new anthocyanins (6–8) were identified, which contained a delphinidin chromophore, and four of these (5–8) were diacylated anthocyanins, in which the acyl-glucosyl-acyl-glucosyl chain was attached at the 7-O-position of the delphinidin chromophore. These diacylated anthocyanins exhibited a bluish-purple color at pH 6, which was stable for more than a week.

Functional Characterization of an Anthocyanin Dimalonyltransferase in Maize

Anthocyanins are pigments with appealing hues that are currently being used as sources of natural colorants. The interaction of acylation on the stability of anthocyanin molecules has long been known. Maize is an abundant source of malonylglucoside and dimalonylglucoside anthocyanins. The enzyme Aat1 is an anthocyanin acyltransferase known to synthesize the majority of acylated anthocyanins in maize. In this paper, we characterize the substrate specificity and reaction kinetics of Aat1. It was found that Aat1 has anthocyanin 3-O-glucoside dimalonyltransferase activity and is only the second enzyme of this type characterized to this date. Our results indicate that Aat1 can utilize malonyl-CoA; succinyl-CoA and every anthocyanin 3-O-glucoside tested. Results of this study provide insight into the structure–function relations of dimalonyltransferases and give a unique insight into the activity of monocot anthocyanin acyltransferases.

Bioactive Compounds and Antioxidant Capacity in Anthocyanin-Rich Carrots: A Comparison between the Black Carrot and the Apulian Landrace “Polignano” Carrot

The carrot is one of the most cultivated vegetables in the world. Black or purple carrots contain acylated anthocyanins which are of special interest to the food industry for their stability and nutraceutical characteristics. Anthocyanin-rich fruits and vegetables have gained popularity in the last ten years, due to the health benefits they provide. In this paper, the characterizations of the bioactive compounds and antioxidant capacities of different anthocyanin-containing carrots (a black carrot—BC, and a local purple carrot, the “Polignano” carrot—PC), compared to the commercial orange carrot (OC) (lacking of anthocyanins), are reported. The anthocyanin profiles of the polyphenolic extracts of BC and PC were similar, but differences were observed at quantitative levels. The total anthocyanin content in BC was more than twice that in PC (13.84 ± 0.61 vs. 5.64 ± 0.48 mg K Eq. g−1 DW). Phenolic acids (mostly chlorogenic acid) were also present at high level in anthocyanin-rich carrots compared to OC. High polyphenol content accounted also for a high reducing capacity (evaluated by Folin–Ciocalteu reagent, FCR), and antioxidant capacity (evaluated by TEAC and ORAC assays) which were the highest for BC (FCR value: 16.6 ± 1.1 mg GAE. g−1 DW; TEAC: 76.6 ± 10.6 µmol TE. g−1 DW; ORAC: 159.9 ± 3.3 µmol TE. g−1 DW). All carrot genotypes (mostly OC) were rich in carotenoids (BC 0.14 ± 0.024; PC 0.33 ± 0.038; OC 1.29 ± 0.09 mg. g−1 DW), with predominance of α and β-carotene, in OC, and lutein in BC. PC showed the highest malic acid and sugar (glucose plus fructose) content. In conclusion, while BC is remarkable for nutraceutical features, the local genotype (“Polignano” carrot) is worth considering in genetic biodiversity conservation programme.