**5. Conclusions**

The addition of grape peels increased the amounts of nutrients in wheat pasta, especially fibers, resistant starch and polyphenols, which are compounds with many health benefits. The optimal quantity of grape peels that can be added to wheat flour was found to be 4.62%. Dough cohesiveness, dry pasta fracturability and cooked pasta chewiness were enhanced compared to the control, while the cooking losses were within acceptable limits (<12%). Starch digestibility of pasta was positively influenced by grape peels, higher resistant starch, slowly digestible starch and lower rapid digestible starch being obtained. Interactions between wheat flour and grape peels were shown trough FT-IR analysis, significant changes of protein structures being observed. A compact microstructure of pasta was noticed at 4.62% addition of small particle sizes (<180 µm). Thus, this study can be helpful for both processors and consumers, underlying the opportunity to enhance the nutritional value of wheat pasta by incorporating grape peels, with benefits for human health and environmental waste management. This research was performed on a laboratory scale, and thus more investigations at the industrial level are needed.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/10 .3390/plants10050926/s1, Figure S1: Effect of GP level on peak viscosity (ηmax); Figure S2: Effect of GP level on dough: a. complex modulus (G\*), b. cohesiveness (Co); Figure S3: Effect of GP level on dry pasta: a. chroma (C\*), b. fracturability (F); Figure S4: Effect of GP level on pasta: a. cooking loss (CL), b. chewiness (Ch); Figure S5: Effect of GP level on pasta: a. resistant starch content (RS), b. total polyphenols content (TPC), c. total dietary fiber (TDF).

**Author Contributions:** The authors contributed equally to this research. All of the authors examined and approved the contents of the article. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded by Stefan cel Mare University of Suceava, Romania.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


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