In the Trentino Alto Adige region, grape stalks (GS) residues disposal is one of the main costs for wine cellars. The development of strategies to valorize agricultural waste, within different supply chains, can serve as a viable and more profitable management approach. Specifically, GS are known to contain nutritional and functional compounds like phenols and tannins that can affect rumen microbiota. This study aimed to assess if supplementing cows with GS could highlight any variation in milk and cheese composition. GS of 3 red grape varieties were collected from a local wine cellar: Lagrein, Cabernet Sauvignon and Merlot. GS were stored at -20°C until the start of the experiment, then dried at 45°C, ground and analyzed for their microbial and chemical safety. Total polyphenols and tannins content were also analyzed. The average content of GS total polyphenols was about 15 g/Kg of dry matter (DM). Following the results obtained, 3 Holstein cows, already fed with hay and concentrates, were selected by a local dairy farm, for the test of daily supplementation with GS at 2% DM of the diet. The study consisted of a one-week control period (CTRL), when no GS supplementation was added to the cows' diet, followed by a week of GS supplementation, for a total of 7 weeks of experimental study (4 CTRL and 3 GS diet weeks). Every week, individual milk samples were collected on the first and last day of the week and analysed for microbiological and chemical composition. Additionally, at the end of each week, 3L of individual milk were collected for experimental mini-cheeses production. A total of 42 milk samples were collected and 21 cheeses were produced. Mini-cheese were processed starting by 2.5 L of milk, ripened for 28 days and analyzed for sensory properties. For milk, routine chemical analyses were performed. Milk and cheese samples were also analyzed for microbial counts. For cheese samples, total polyphenol content, water activity and NMR analysis were performed. Preliminary results showed no correlation between milk microbiological count and the diet: mean values of coliforms in milk samples were always in the range 2.3 – 2.4 log UFC/mL and mean values of bacteria total count were always in the range 5.0 – 5.1 log UFC/mL. Total polyphenols mean in cheese samples were always in the range 203 – 211 mg/Kg. Other test and statistical analysis are under progress. This study was carried out within the Interconnected Nord-Est Innovation Ecosystem (iNEST) and received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.5 – D.D. 1058 23/06/2022, ECS00000043). This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them.
Promoting a circular bio-economy: use of wine cellar by-products as feed supplement for dairy cows and evaluation of the chemical and microbiological effects on dairy products
Giulia Dallavalle;
2025
Abstract
In the Trentino Alto Adige region, grape stalks (GS) residues disposal is one of the main costs for wine cellars. The development of strategies to valorize agricultural waste, within different supply chains, can serve as a viable and more profitable management approach. Specifically, GS are known to contain nutritional and functional compounds like phenols and tannins that can affect rumen microbiota. This study aimed to assess if supplementing cows with GS could highlight any variation in milk and cheese composition. GS of 3 red grape varieties were collected from a local wine cellar: Lagrein, Cabernet Sauvignon and Merlot. GS were stored at -20°C until the start of the experiment, then dried at 45°C, ground and analyzed for their microbial and chemical safety. Total polyphenols and tannins content were also analyzed. The average content of GS total polyphenols was about 15 g/Kg of dry matter (DM). Following the results obtained, 3 Holstein cows, already fed with hay and concentrates, were selected by a local dairy farm, for the test of daily supplementation with GS at 2% DM of the diet. The study consisted of a one-week control period (CTRL), when no GS supplementation was added to the cows' diet, followed by a week of GS supplementation, for a total of 7 weeks of experimental study (4 CTRL and 3 GS diet weeks). Every week, individual milk samples were collected on the first and last day of the week and analysed for microbiological and chemical composition. Additionally, at the end of each week, 3L of individual milk were collected for experimental mini-cheeses production. A total of 42 milk samples were collected and 21 cheeses were produced. Mini-cheese were processed starting by 2.5 L of milk, ripened for 28 days and analyzed for sensory properties. For milk, routine chemical analyses were performed. Milk and cheese samples were also analyzed for microbial counts. For cheese samples, total polyphenol content, water activity and NMR analysis were performed. Preliminary results showed no correlation between milk microbiological count and the diet: mean values of coliforms in milk samples were always in the range 2.3 – 2.4 log UFC/mL and mean values of bacteria total count were always in the range 5.0 – 5.1 log UFC/mL. Total polyphenols mean in cheese samples were always in the range 203 – 211 mg/Kg. Other test and statistical analysis are under progress. This study was carried out within the Interconnected Nord-Est Innovation Ecosystem (iNEST) and received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.5 – D.D. 1058 23/06/2022, ECS00000043). This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them.
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