**4. Conclusions**

*Innovation in the Food Sector Through the Valorization of Food and Agro-Food By-Products*

**\*\*\***

**10**

**Wine lees**

> **Sousão**

Z0.422 ± 0.001a

0.503 ± 0.003b

0.750 ± 0.002d

0.641 ± 0.002c

nd

nd

Y**\*\*\***

1. Gallic acid 2. Isorhammetin-3-

3. Caftaric acid 4. Protocatechuic acid

5. *p*-coumaric acid

6. Delphinidin-3-

7. Catechin 8. Epicatechin 9. Petunidin-3-

10. Malvidin-3-

11. Quercetin-3-

12. Quercetin-3-

13. Kaempferol-3-

14. Kaempferol-3-

15. ԑ-viniferin *YLevel of significance: N.s.: not significant ( > 0.05);*

∗*significant at < 0.05;*

∗∗*significant at < 0.01;*

∗∗∗*significant at < 0.001. nd: not detected.*

**Table 2.**

*range test (Tukey's test) with a significance of p < 0.05.*

*Content of individual phenolics (mg g−1 dw) of WBPs from Sousão and Tinta Barroca varieties. Statistical treatment notes: Data were subjected to analysis of variance (ANOVA) and multiple* 

*O*-glucoside

*O*-rutinoside

*O*-glucoside

*O*-rutinoside

*O*-glucoside

*O*-glucoside

*O*-glucoside

*O*-(6-

*O*-feruloyl)-glucoside

nd nd 0.216 ± 0.001a

nd 0.123 ± 0.002a 0.559 ± 0.010a 0.498 ± 0.001b 0.215 ± 0.005a 0.875 ± 0.023a

nd nd nd nd nd

nd *ZData presented as Mean (n = 3) ± SD values in the same row followed by different superscript lowercase letters are significantly different at p < 0.001, according to Tukey's test.*

nd

nd

0.087 ± 0.002c

0.109 ± 0.004d

**\*\***

nd

0.305 ± 0.003c

nd

nd

0.458 ± 0,011c 0.207 ± 0.001d

0.110 ± 0.001c 0.401 ± 0.001d

0.211 ± 0.001a

0.286 ± 0.006b

**\*\*\***

0.071 ± 0,001a

0.102 ± 0.003b

**\*\***

0.385 ± 0.062a

0.374 ± 0,013a

0.423 ± 0.019b

**\*\***

nd

0,450 ± 0,002c

0.214 ± 0.012a

0.369 ± 0,003b

0.605 ± 0.010d

**\*\***

0.968 ± 0.012c

0.321 ± 0.007b

nd 1.002 ± 0.024d

0.934 ± 0.017b

nd

nd

**\*\*\***

nd

nd

nd

**\*\***

0.660 ± 0.005d

0.601 ± 0.007c

0.412 ± 0.003a

nd

nd

0.798 ± 0.018b

1.501 ± 0.025d

0.993 ± 0.031c

nd

nd

**\*\*\***

nd 0.258 ± 0.001b

nd

nd

nd

nd

**\*\***

nd 0.458 ± 0.001b

nd 0.434 ± 0.005b

0.125 ± 0.002a

nd

nd

**\*\*\***

nd

nd

nd

**\*\***

nd

nd

0.171 ± 0.003a

0.225 ± 0.008b

**\*\*\***

nd

nd

nd

0.203 ± 0.001a

0.338 ± 0.001b

**\*\*\***

**Tinta Barroca**

**Sousão**

**Tinta Barroca**

**Sousão**

**Tinta Barroca**

**Grape pomace**

**Grape stems**

*P***-value**

Nowadays, it is well established in the scientific community that wine has an important role in the prevention of some cardiovascular diseases, resulting from their content in bioactive phytochemicals with antioxidant capacity. Many of these compounds are derived from the solid parts of the grape cluster (stem, pomace, trimmed vine shoots, and wine lees). However, during the winemaking process, a complete extraction of these compounds to the juice/wine does not occur, and they may remain at high concentrations in certain wastes, such as in the stems. Indeed, the wine industry involves the production of large quantities of by-products, characterized by a valuable composition in phytochemicals with putative health-promoting qualities. Additionally, in light of the biological properties revealed recently, the search for natural bioactive compounds has paid attention on these materials as promising alternatives.

In this work, it was possible to observe the high content of phenolic compounds and the high antioxidant capacities demonstrated by several winery by-products, namely wine lees, grape pomace, and grape stems which were subjected to an ultrasound assisted extraction, obtaining higher values than those obtained by conventional extraction methods employed by the research group.

In this sense, the phenolics present in winery by-products may have an addedvalue to be used as an alternative to synthetic substances employed in distinct industries, giving rise to sustainable agro-industrial activities.

### **Acknowledgements**

This work is supported by National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020 (CITAB). We also acknowledge Eng. Manuel Henrique from ROZÉS who kindly provided the samples.
