Evolution of volatile profile and aroma potential of 'Gold Finger' table grapes during berry ripening.

BACKGROUND: 'Gold Finger' is a grape cultivar with a finger-like shape and a milk flavor. The process by which its aroma profile evolves during ripening is unclear. Thus, changes in the free and bound volatile compounds present in 'Gold Finger' grapes during ripening were investigated using headspace sampling-solid-phase microextraction-gas chromatography-mass spectroscopy (HS-SPME-GC-MS). RESULTS: A total of 83 volatile aroma components were identified in the grapes, with aldehydes, esters, acids, and alcohols being the main components. The total aroma compound content exhibited significant differences between the bound and free forms. The total content of bound volatile compounds did not change significantly during fruit development, although the free aroma compound content was significantly higher than the bound content. The total content of free aldehydes, free alcohols, bound norisoprenoids, and ketones gradually increased for up to 70 days after flowering (DAF), while the total free ester, terpene, and acid content decreased. The characteristic aroma compounds of 'Gold Finger' grapes were identified as hexanal, (E)-2-hexenal, and ethyl hexanoate. CONCLUSIONS: These results give a foundation for the further development of 'Gold Finger' grapes and provide a theoretical basis for the selection and breeding of novel aromatic grape varieties. © 2021 Society of Chemical Industry.

Differential effects of phenolic extracts from red-fleshed apple peels and flesh induced G1 cell cycle arrest and apoptosis in human breast cancer MDA-MB-231 cells.

Red-fleshedapples are preferredbecause of their high content of phenolics and antioxidants in peel and pulp. Herein, we evaluated the mechanisms of apple peel polyphenolic extracts (APP) and apple flesh polyphenolic extracts (AFP) from the new red-fleshed apple in inhibiting cell proliferation and inducing apoptosis on human breast cancer MDA-MB-231 cells. The antiproliferative activities were determined by the CCK8 assay. The expression of proteins was determined using Western blot. We found that the content of polyphenols and flavonoids in APP was significantly higher than that in AFP, and 14 main phenolic compounds in APP and AFP were quantified using UPLC-MS/MS techniques. Besides, the significant inhibition effects of APP and AFP were achieved through Akt pathway by inducing apoptosis (significantly upregulating reactive oxygen species [ROS] levels, and downregulating expression of pAkt, pBad, Bcl-2, promoting Cytochrome c release, activating Cle-Caspase 9, and inducing expressions of Cle-Caspase 3 and Cle-PARP), and inducing G0/G1 cell cycle arrest (increased expressions of p-p53 and p21 and decreased expressions of PCNA and Cyclin D1). And the inhibition effect of APP was stronger than that of AFP. These results suggest that AFP and APP may be excellent sources of natural chemicals for treating triple-negative breast cancer MDA-MB-231 cells. PRACTICAL APPLICATION: The effects of antiproliferation of phenolic extracts from red-fleshed apple peels and flesh on human breast cancer MDA-MB-231 cells were evaluated. The data may clarify the functional parts of red-fleshed apple and provide some basis for scientific researchers and consumers to recognize and exploit red-fleshed apple.

Phytochemical profiles, antioxidant, and antiproliferative activities of red-fleshed apple as affected by in vitro digestion.

The aim of this study was to characterize the phenolic profiles in the extracts and digesta (after in vitro digestion) of different red-fleshed apple fruit parts and to assess the effects of digestion on the in vitro antioxidant capacity and antiproliferative activity. The main polyphenols were identified by UPLC-MS/MS and HPLC. Our results indicate that the digesta had less total phenolics, flavonoids, and anthocyanins, but more free phenolic acids, than the extracts. An analysis of the in vitro antioxidant capacity (including ABTS radical scavenging activity, DPPH radical-scavenging capacity, ferric reducing antioxidant power [FRAP], and cellular antioxidant activity [CAA]) revealed that the digestion decreased the ABTS, DPPH, and FRAP values, but increased the CAA values, relative to the corresponding values for extracts. These results suggest that the digestion improved the effectiveness of the phenolic substances. Moreover, our findings imply that the digestion promoted the antiproliferative activity of red-fleshed apple peels and flesh relative to the extracts. Future in vivo investigations are warranted based on the results of the current study. PRACTICAL APPLICATION: The effects of an in vitro digestion on the phenolic compounds as well as the antioxidative and antiproliferative activities of red-fleshed apple were evaluated. The resulting data may clarify the bioavailability of the polyphenols in red-fleshed apple and enable scientists and consumers to exploit natural polyphenols.

Phytochemical profiles, antioxidant, and antiproliferative activities of four red-fleshed apple varieties in China.

Red-fleshed apples are preferred because of their high content of phenolics and antioxidants. In this study, the phenolic characteristics, antioxidant properties, and antihuman cancer cell properties of the four hybrids of Malus sieversii f. niedzwetzkyana (Ledeb.) M. Roem were analyzed. In addition, the antioxidant and anti-proliferation properties of these apples were measured. Compared to "Fuji" apples, the red-fleshed apples were rich in phenolic and flavonoid chemicals, ranging from 1.5- to 2.6-fold and 1.4- to 2.4-fold, respectively. In all antioxidant methods (DPPH radical-scavenging capacity, ABTS radical scavenging activity, ferric reducing antioxidant power, and cell antioxidant capacity), "A38" obtained the highest antioxidant value, whereas "Fuji" got the lowest antioxidant value. The IC50 values ranged from 33.44 ("A38") to 73.36 mg/mL ("Fuji") for MCF-7 and 20.94 ("A38") to 39.39 mg/mL ("Fuji") for MAD-MB-231. The red-fleshed "A38" and "Meihong" exhibited higher antioxidant and antiproliferative activities in vitro because of the higher levels of phenolics, and the higher potential for development and utilization value. PRACTICAL APPLICATION: The phenolic compounds, antioxidant activity, and antiproliferative activity in vitro of four red-fleshed apple cultivars and one white-fleshed apple cultivar were compared in this study. This information should assist to give a reasonable evaluation for scientists to breed new cultivars with high phenolics and to exploit the natural polyphenol.

Cluster bagging promotes melatonin biosynthesis in the berry skins of Vitis vinifera cv. Cabernet Sauvignon and Carignan during development and ripening.

Melatonin, a tryptophan derivative, is an important functional component in grape berries. We investigated the effect of cluster bagging on melatonin biosynthesis in the berries of two wine grape cultivars, Cabernet Sauvignon and Carignan, during fruit development and ripening. Cluster bagging delayed fruit coloring and ripening, and bag-treated berries of both grape cultivars synthesized more melatonin and most of the precursor compounds including L-tryptophan, N-acetylserotonin, tryptamine, and serotonin compared to those exposed to light (control) conditions. Interestingly, 5-methoxytryptamine was only detected in the berries of Carignan and not of Cabernet Sauvignon, both in the cluster bagging and control groups. In addition, melatonin and most of its precursors, decreased after veraison. VvSNAT1 and VvT5H expression levels were positively correlated with melatonin content. Our findings suggested that melatonin synthesis pathways differ among grape cultivars, and that VvSNAT1 and VvT5H may show key regulatory roles in the melatonin synthesis of grape berries.