Estratto di uva syrah (Vitis vinifera L.)

L’estratto di uva syrah è una preparazione ottenuta da bucce, polpa e talvolta vinaccioli della cultivar a bacca nera “syrah/shiraz”, ricca di polifenoli antocianici e tannini. È impiegato come ingrediente aromatizzante e, in determinate frazioni, come fonte di colore naturale, oltre che come estratto funzionale per alimenti, integratori e cosmetici.

Valore calorico (per 100 g di prodotto)
Estratto idroalcolico: circa 50–150 kcal/100 g (dipende da solidi e EtOH residuo).
Estratto glicerico/glicolico: circa 150–300 kcal/100 g.
Estratto secco standardizzato (polvere): circa 250–350 kcal/100 g.
Ai dosaggi d’uso alimentari il contributo energetico è in genere modesto.

Principali sostanze contenute
Polifenoli: antociani (malvidina-3-glucoside e congeneri), proantocianidine/tannini condensati (soprattutto da vinaccioli), flavonoli (quercetina), acidi fenolici (gallico, caffeico).
Acidi organici: tartarico (prevalente) e malico, con effetto su pH e stabilità del colore.
Componenti minori: zuccheri residui (grado °Brix variabile), composti azotati, tracce di volatili; in estratti da bucce possono essere presenti norisoprenoidi e, in tracce, rotundone.
Marcatori analitici: polifenoli totali (TPC, Folin–Ciocalteu, espressi come equivalenti di acido gallico), antociani monomerici profilati con HPLC.

Processo di produzione
Materie prime: selezione di bucce/polpa (talvolta vinaccioli) da uve syrah fresche o da sottoprodotti enologici idonei.
Estrazione: macerazione in acqua/EtOH a pH controllato, oppure in glicerina/glicoli; in alternativa membrane o resine a scambio per arricchire le frazioni coloranti (antociani).
Chiarifica e concentrazione: filtrazione, eventuale pulizia selettiva di impurità, concentrazione a bassa temperatura; standardizzazione del titolo in TPC e/o antociani.
Controlli qualità: profilo HPLC (antociani/marker), parametri chimico-fisici (°Brix, pH), residuo di EtOH (se rilevante), metalli/pesticidi, microbiologia.
Confezionamento: imballi barriera a luce/ossigeno secondo GMP/HACCP con CCP su igiene e tracciabilità.

Proprietà sensoriali e tecnologiche
Aroma/colore: note fruttate scure e vinose; le frazioni antocianiche conferiscono tonalità rosso–porpora. Il colore è dipendente da pH (rossi vivi in ambiente acido; viraggi verso violaceo/blu a pH più elevato).
Funzionalità: attività antioxidant dei polifenoli; possibile contributo astringente/strutturante; capacità di mascherare leggere note ossidative.
Compatibilità: in matrici ricche di proteine possono formarsi complessi polifenolo–proteina con rischio di torbidità/precipitazione.

Impieghi alimentari
Bevande analcoliche/acidulate, sciroppi, confetteria, topping e salse, prodotti da forno e ripieni, cioccolato e dessert. Per applicazioni coloranti si usano frazioni di bucce (antociani, talvolta riconducibili a E163). Dosaggi tipici: 0,05–0,30% in liquidi, o secondo target colore/aroma da definire con prove pilota.

Nutrizione e salute
L’estratto apporta polifenoli con attività antioxidant in vitro; in ambito alimentare non si attribuiscono indicazioni salutistiche senza specifica autorizzazione. La presenza di EtOH residuo (estratti idroalcolici) e di eventuali solfiti va considerata per l’etichettatura.

Qualità e specifiche (temi tipici)
Titolo in TPC (Folin–Ciocalteu) e profilo HPLC degli antociani; colore (assorbanza ~520 nm), °Brix, pH.
Residuo di EtOH ove applicabile; metalli/pesticidi entro limiti; microbiologia conforme.
Assenza di off-flavors e stabilità a luce/ossigeno; tracciabilità completa sotto GMP/HACCP.

Conservazione e shelf-life
Conservare al fresco e al buio in contenitori ben chiusi a bassa permeabilità; minimizzare DO nelle soluzioni e l’ossigeno nello spazio di testa.
Controllare RH e aw per le polveri; evitare cicli termici che accelerano lo sbiadimento del colore.
Applicare rotazione FIFO.

Allergeni e sicurezza
L’uva non è tra gli allergeni maggiori; estratti da filiere enologiche possono contenere solfiti. È necessario verificare i requisiti locali di etichettatura e limitare EtOH per categorie sensibili.

Funzioni INCI in cosmesi
Voci tipiche: Vitis Vinifera (Grape) Fruit Extract, Vitis Vinifera (Grape) Skin Extract. Ruoli: antioxidant, skin conditioning, blando astringente, mascherante. Gli estratti glicerici apportano anche lieve umettanza.

Troubleshooting
Perdita di colore: pH elevato, luce o ossigeno → acidificare entro i limiti di prodotto, proteggere da luce/DO, usare antiossidanti idonei.
Torbidità/precipitato: complessi polifenolo–proteina o metalli → chiarifica, chelanti blandi, filtrazione fine.
Astringenza eccessiva: dose alta o frazione ricca in tannini → ridurre dose o scegliere estratti più “soft”.
Variabilità lotto-lotto: materia prima/estrazione → standardizzare su TPC/antociani con specifiche strette.

Sostenibilità e filiera
Upcycling di bucce/vinaccioli, recupero energetico e gestione degli effluenti rispetto a target BOD/COD riducono l’impronta. Imballaggi riciclabili e logistica a temperatura controllata migliorano stabilità e impatto ambientale.

Conclusione
L’estratto di uva syrah combina colore, note fruttate scure e funzionalità polifenolica. La resa applicativa dipende da qualità della materia prima, profilo di pH, protezione da luce/ossigeno e corretta standardizzazione; con questi presidi si ottengono prodotti stabili e ripetibili.

Mini-glossario
EtOH — etanolo: co-solvente idroalcolico; rilevante anche per l’etichettatura quando residuo.
°Brix — percentuale in massa di solidi solubili (zuccheri) in soluzione.
pH — misura di acidità/alcalinità; governa tonalità e stabilità degli antociani.
TPC — total phenolic content: contenuto fenolico totale (Folin–Ciocalteu).
HPLC — high-performance liquid chromatography: titolazione/identificazione di antociani e altri marcatori.
E163 — antociani: classe di coloranti alimentari di origine vegetale (UE).
SO₂/solfiti — anidride solforosa/solfiti: antiossidanti/conservanti; da dichiarare quando presenti.
DO — dissolved oxygen: ossigeno disciolto; ridurlo limita ossidazioni e sbiadimenti.
RH — umidità relativa: valori alti favoriscono caking e degrado delle polveri.
aw — attività dell’acqua: quota di acqua “libera”, utile a prevedere stabilità e microbiologia.
GMP — good manufacturing practice: buone pratiche di produzione per igiene e coerenza.
HACCP — hazard analysis and critical control points: sistema preventivo con CCP definiti.
CCP — critical control point: fase in cui un controllo previene/elimina/riduce un pericolo.
FIFO — first in, first out: rotazione scorte che privilegia l’uso dei lotti più vecchi.

Bibliografia__________________________________________________________________________

Kang W, Bindon KA, Wang X, Muhlack RA, Smith PA, Niimi J, Bastian SEP. Chemical and Sensory Impacts of Accentuated Cut Edges (ACE) Grape Must Polyphenol Extraction Technique on Shiraz Wines. Foods. 2020 Jul 31;9(8):1027. doi: 10.3390/foods9081027.

Abstract. Accentuated Cut Edges (ACE) is a recently developed grape must extraction technique, which mechanically breaks grape skins into small fragments but maintains seed integrity. This study was the first to elucidate the effect of ACE on Shiraz wine's basic chemical composition, colour, phenolic compounds, polysaccharides and sensory profiles. A further aim was to investigate any potential influence provided by ACE on the pre-fermentation water addition to must. ACE did not visually affect Shiraz wine colour, but significantly enhanced the concentration of tannin and total phenolics. Wine polysaccharide concentration was mainly increased in response to the maceration time rather than the ACE technique. ACE appeared to increase the earthy/dusty flavour, possibly due to the different precursors released by the greater skin breakage. The pre-fermentation addition of the water diluted the wine aromas, flavours and astringency profiles. However, combining the ACE technique with water addition enhanced the wine textural quality by increasing the intensities of the crucial astringent wine quality sub-qualities, adhesive and graininess. Furthermore, insights into the chemical factors influencing the astringency sensations were provided in this study. This research indicates that wine producers may use ACE with pre-fermentation water dilution to reduce the wine alcohol level but maintain important textural components.

Antalick G, Šuklje K, Blackman JW, Meeks C, Deloire A, Schmidtke LM. Influence of Grape Composition on Red Wine Ester Profile: Comparison between Cabernet Sauvignon and Shiraz Cultivars from Australian Warm Climate. J Agric Food Chem. 2015 May 13;63(18):4664-72. doi: 10.1021/acs.jafc.5b00966. 

Abstract. The relationship between grape composition and subsequent red wine ester profile was examined. Cabernet Sauvignon and Shiraz, from the same Australian very warm climate vineyard, were harvested at two different stages of maturity and triplicate wines were vinified. Grape analyses focused on nitrogen and lipid composition by measuring 18 amino acids by HPLC-FLD, 3 polyunsaturated fatty acids, and 6 C6-compounds derived from lipid degradation by GC-MS. Twenty esters and four higher alcohols were analyzed in wines by HS-SPME-GC-MS. Concentrations of the ethyl esters of branched acids were significantly affected by grape maturity, but the variations were inconsistent between cultivars. Small relative variations were observed between wines for ethyl esters of fatty acids, whereas higher alcohol acetates displayed the most obvious differences with concentrations ranging from 1.5- to 26-fold higher in Shiraz than in Cabernet Sauvignon wines regardless of the grape maturity. Grape analyses revealed the variations of wine ester composition might be related to specific grape juice nitrogen composition and lipid metabolism. To the authors' knowledge the present study is the first to investigate varietal differences in the ester profiles of Shiraz and Cabernet Sauvignon wines made with grapes harvested at different maturity stages.

Davies C, Nicholson EL, Böttcher C, Burbidge CA, Bastian SE, Harvey KE, Huang AC, Taylor DK, Boss PK. Shiraz wines made from grape berries (Vitis vinifera) delayed in ripening by plant growth regulator treatment have elevated rotundone concentrations and "pepper" flavor and aroma. J Agric Food Chem. 2015 Mar 4;63(8):2137-44. doi: 10.1021/jf505491d.

Abstract. Preveraison treatment of Shiraz berries with either 1-naphthaleneacetic acid (NAA) or Ethrel delayed the onset of ripening and harvest. NAA was more effective than Ethrel, delaying harvest by 23 days, compared to 6 days for Ethrel. Sensory analysis of wines from NAA-treated fruit showed significant differences in 10 attributes, including higher "pepper" flavor and aroma compared to those of the control wines. A nontargeted analysis of headspace volatiles revealed modest differences between wines made from control and NAA- or Ethrel-treated berries. However, the concentration of rotundone, the metabolite responsible for the pepper character, was below the level of detection by solid phase microextraction-gas chromatography-mass spectrometry in control wines, low in Ethrel wines (2 ng/L), and much higher in NAA wines (29 ng/L). Thus, NAA, and to a lesser extent Ethrel, treatment of grapes during the preveraison period can delay ripening and enhance rotundone concentrations in Shiraz fruit, thereby enhancing wine "peppery" attributes.

Fang Y, Kravchuk O, Taylor DK. Chemical Changes in Grape Stem and Their Relationship to Stem Color throughout Berry Ripening in Vitis vinifera L. cv Shiraz. J Agric Food Chem. 2015 Feb 4;63(4):1242-1250. doi: 10.1021/jf504215e. 

Abstract. Little attention has been paid to the color change or chemical compositional changes that occur in grape stems and how this correlates with the berry ripening process. Recently we have found that the change in grape peduncle color of Shiraz (Vitis vinifera) from green at veraison to predominantly brown at harvest occurs in parallel with berry ripening and as such may represent a new way of assisting in the prediction of grape maturity and harvest date. We have now investigated further the link between certain key chemical compositional changes that occur in the grape stem (peduncle and rachis) from veraison to harvest and how these attributes correlate with the observed color change in the vineyard. We report that peduncle moisture content has an excellent linear correlation with the color hue value and is negatively correlated in a strong fashion with the chlorophyll and carotenoid pigment ratio (Ca+b/Cx+c) within the peduncles. Significant differences in the moisture content, total chlorophylls (including chlorophyll a and b levels), total carotenoids, total phenolics, and the antioxidant capacity (DPPH) levels between the peduncles and rachises were found as they evolve from veraison to harvest. Finally, we have demonstrated for the first time that peduncle moisture content codevelops with the prototypical berry ripeness parameters (oBrix, pH, TA), which provides for the development of a new approach for viticulturists and winemakers to evaluate grape ripeness through peduncle moisture levels and therefore assist in harvest decision making.

Boss PK, Davies C, Robinson SP. Analysis of the Expression of Anthocyanin Pathway Genes in Developing Vitis vinifera L. cv Shiraz Grape Berries and the Implications for Pathway Regulation. Plant Physiol. 1996 Aug;111(4):1059-1066. doi: 10.1104/pp.111.4.1059. 

Abstract. Anthocyanin synthesis in Vitis vinifera L. cv Shiraz grape berries began 10 weeks postflowering and continued throughout berry ripening. Expression of seven genes of the anthocyanin biosynthetic pathway (phenylalanine ammonia lyase [PAL], chalcone synthase [CHS], chalcone isomerase [CHI], flavanone-3-hydroxylase [F3H], dihydroflavonol 4-reductase [DFR], leucoanthocyanidin dioxygen-ase [LDOX], and UDP glucose-flavonoid 3-o-glucosyl transferase [UFGT]) was determined. In flowers and grape berry skins, expression of all of the genes, except UFGT, was detected up to 4 weeks postflowering, followed by a reduction in this expression 6 to 8 weeks postflowering. Expression of CHS, CHI, F3H, DFR, LDOX, and UFGT then increased 10 weeks postflowering, coinciding with the onset of anthocyanin synthesis. In grape berry flesh, no PAL or UFGT expression was detected at any stage of development, but CHS, CHI, F3H, DFR, and LDOX were expressed up to 4 weeks postflowering. These results indicate that the onset of anthocyanin synthesis in ripening grape berry skins coincides with a coordinated increase in expression of a number of genes in the anthocyanin biosynthetic pathway, suggesting the involvement of regulatory genes. UFGT is regulated independently of the other genes, suggesting that in grapes the major control point in this pathway is later than that observed in maize, petunia, and snapdragon.

Garrido-Bañuelos G, Buica A, Schückel J, Zietsman AJJ, Willats WGT, Moore JP, Du Toit WJ. Investigating the relationship between grape cell wall polysaccharide composition and the extractability of phenolic compounds into Shiraz wines. Part I: Vintage and ripeness effects. Food Chem. 2019 Apr 25;278:36-46. doi: 10.1016/j.foodchem.2018.10.134. Epub 2018 Oct 30. PMID: 30583384.

Garrido-Bañuelos G, Buica A, Schückel J, Zietsman AJJ, Willats WGT, Moore JP, Du Toit WJ. Investigating the relationship between cell wall polysaccharide composition and the extractability of grape phenolic compounds into Shiraz wines. Part II: Extractability during fermentation into wines made from grapes of different ripeness levels. Food Chem. 2019 Apr 25;278:26-35. doi: 10.1016/j.foodchem.2018.10.136. Epub 2018 Oct 30. PMID: 30583371.

Souza EL, Nascimento TS, Magalhães CM, Barreto GA, Leal IL, Dos Anjos JP, Machado BAS. Development and Characterization of Powdered Antioxidant Compounds Made from Shiraz (Vitis vinifera L.) Grape Peels and Arrowroot (Maranta arundinacea L.). ScientificWorldJournal. 2022 Apr 26;2022:7664321. doi: 10.1155/2022/7664321.