Giovanna Giovinazzo

Osteoporosis is an age-related metabolic bone disorder characterized by an imbalance between bone resorption and formation. Natural polyphenols have gained attention as potential complementary strategies for its prevention. In this study, we investigated the effects of a sustainable, polyphenol-rich extract from red grape pomace (GPE) on human mesenchymal stem cell (MSC) fate and its underlying mechanisms of action. We found that GPE significantly promoted osteogenic differentiation while suppressing adipogenic differentiation in canonical bone marrow-derived MSCs (BMSCs). This biological effect was preserved in adipose tissue-derived MSCs (AdMSCs) obtained from elderly patients (>65 years) at high cardiovascular risk. Mechanistically, GPE downregulated adipogenic markers (PPARγ, CD36 and FABP4) and enhanced osteogenic markers (RUNX2, ALP, OSX, BMP-2, OPN, COL1A1 and OCN). Moreover, GPE activated NRF2-dependent redox signaling, as evidenced by increased NRF2 nuclear translocation and transcriptional activity. Accordingly, GPE treatment significantly upregulated, or consistently increased, the expression of multiple NRF2 target genes, including HO-1, GPX, CAT, GCLC, and NQO1. Importantly, pharmacological inhibition of NRF2 attenuated GPE-induced ALP activity, confirming NRF2 as a key mediator of its osteogenic effects. Overall, grape pomace-derived polyphenols act as upstream modulators of redox-sensitive and osteogenic transcription factors, rebalancing MSC differentiation toward osteogenesis and mitigating age-related bone fragility.

In this study, grape pomace is used as an ingredient to fortify pasta. The grape pomace phenolic component is highly accessible and available for metabolization in the human gut. Hence, grape pomace can be exploited as a source of polyphenols and fiber for sustainable and dietary beneficial food production. Analyses of soluble and bound phenols and volatile compounds in raw and cooked pasta were performed. In the uncooked pasta fortified with pomace, the content of soluble and bound phenolic molecules increased significantly. During the cooking process, the bound phenols were lost, while the soluble phenols doubled. The whole grape pomace flour as a pasta ingredient increased the fiber component by at least double, increased the soluble polyphenol component by at least 10 times, and doubled the isoprenoids (toco-chromanols and carotenoids) while maintaining the unaltered fatty acid content after cooking. In accordance with the polyphenol content, antioxidant activity resulted higher than that of the control pasta. Analysis of volatile compounds in fortified pasta, both uncooked and cooked, indicated an improvement in aromatic profile when compared to the control pasta. Our results show that durum wheat pasta fortified with whole pomace flour has bioactive potential for the reuse of food industry byproducts.

In this work, novel bio-based hydrogel beads were fabricated by using soybean extract as raw waste material loaded with Lambrusco extract, an Italian grape cultivar. The phenolic profile and the total amount of anthocyanins from the Lambrusco extract were evaluated before encapsulating it in soybean extract-based hydrogels produced through an ionotropic gelation technique. The physical properties of the produced hydrogel beads were then studied in terms of their morphological and spectroscopic properties. Swelling degree was evaluated in media with different pH levels. The release kinetics of Lambrusco extract were then studied over time as a function of pH of the release medium, corroborating that the acidity/basicity could affect the release rate of encapsulated molecules, as well as their counter-diffusion. The pH-sensitive properties of wine extract were studied through UV-Vis spectroscopy while the colorimetric responses of loaded hydrogel beads were investigated in acidic and basic solutions. Finally, in the framework of circular economy and sustainability, the obtained data open routes to the design and fabrication of active materials as pH-indicator devices from food industry by-products.

Grape pomace, as by-product of wine making, is a source of polyphenols, fibers, fatty acids, metals, and organic acids, which could be used as raw component for the production of sustainable materials. Novel biodegradable films based on pomaces, from Negroamaro (red) and Fiano (white), Italian grape cultivars, were fabricated. Physical, chemical and antioxidant properties of material produced were characterized. In particular, migration tests of phenols from pomace films to aqueous food simulant medium were investigated. Data obtained allowed to evaluate the antioxidant activity in terms of total phenol assay and Trolox Equivalent Antioxidant Capacity assay and phenols profile. The characterization of phenolic composition confirmed the peculiarity of some compounds such as anthocyanins (191.17 ± 10.3 μg/g film) in red skin pomace film (NPF) and a great amount of flavanols (76.36 ± 1.72 μg/g film) in white skin pomace film (FPF). Antioxidant activity of polyphenols resulted in active films and was confirmed in migration test with aqueous food simulants. Physical properties of produced films were then studied in terms of morphological, thermal, mechanical and barrier properties. Finally, in the framework of sustainability and circular economy, the presented data paves the way to the design and production of active materials for packaging application starting from a widely available by-product derived from wine-making chain.

Research on flavonoids from plant sources is showing growing evidence of the versatile health benefits of flavonoids through in vitro and in vivo studies

Background: Grape pomace is highly attractive for the food industry as it contains numerous bioactive molecules relevant for human health. However, in order to exploit pomace flour as a functional food ingredient for food industry, it is important understand how long-term storage affects the stability of both bioactive molecules and volatile compounds, in addition to color. To this end, we analyzed whole pomace flour from red grape during a six-month storage period in the dark, either at 4 °C or 25 °C. Methods: The specific parameters monitored of grape pomace flour included: antioxidant activity (TEAC assay), total phenol content (Folin-Ciocalteu assay), phenol composition (high performance liquid chromatography), fatty acid composition (gas chromatography-mass spectrometry), volatile compound profiles (headspace-solid phase micro-extraction) and color. Results: Prolonged storage did not significantly affect total phenol content, antioxidant activity and characterized bioactive molecules (polyphenols, fatty acids). The only detected effect of storage was a slight whitening of the pomace flour and a small increase of volatile long chain esters and ketons after 6 months at 25 °C. Conclusions: The activity of several health-relevant bioactive compounds remained stable following storage of pomace flour for 6 months at 4 °C, supporting its possible use as a functional food ingredient.

Inflammatory bowel disease (IBD) implies the chronic inflammation of the gastrointestinal tract, combined with systemic vascular manifestations. In IBD, the incidence of cardiovascular disease appears to be related to an increase of oxidative stress and endothelial dysfunction. Grape pomace contains high levels of anti-oxidant polyphenols that are able to counteract chronic inflammatory symptoms. The aim of this study was to determine whether grape pomace polyphenolic extract (GPE) was able to mitigate the overwhelming inflammatory response in enterocyte-like cells and to improve vascular function. Intestinal epithelial Caco-2 cells, grown in monolayers or in co-culture with endothelial cells (Caco-2/HMEC-1), were treated with different concentrations of GPE (1, 5, 10 µg/mL gallic acid equivalents) for 2 h and then stimulated with lipopolysaccharide (LPS) and tumor necrosis factor (TNF)-α for 16 h. Through multiple assays, the expression of intestinal and endothelial inflammatory mediators, intracellular reactive oxygen species (ROS) levels and NF-κB activation, as well as endothelial-leukocyte adhesion, were evaluated. The results showed that GPE supplementation prevented, in a concentration-dependent manner, the intestinal expression and release of interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, and matrix metalloproteinases (MMP)-9 and MMP-2. In Caco-2 cells, GPE also suppressed the gene expression of several pro-inflammatory markers, such as IL-1β, TNF-α, macrophage colony-stimulating factor (M-CSF), C-X-C motif ligand (CXCL)-10, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, and cyclooxygenase (COX)-2. The GPE anti-inflammatory effect was mediated by the inhibition of NF-κB activity and reduced intracellular ROS levels. Furthermore, transepithelial GPE suppressed the endothelial expression of IL-6, MCP-1, VCAM-1, and ICAM-1 and the subsequent adhesion of leukocytes to the endothelial cells under pro-inflammatory conditions. In conclusion, our findings suggest grape pomace as a natural source of polyphenols with multiple health-promoting properties that could contribute to the mitigation of gut chronic inflammatory diseases and improve vascular endothelial function.