Proceeding of Veterinary and Animal Science Days 2017, 6th- 8th June, Milan, Italy 
 

HAF © 2013 

Vol. IV, No. 1s   ISSN: 2283-3927 

   

 

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Keywords 

Agrifood wastes, Antioxidant 

capacity, Phenolic compounds, 

Functional feed 

 

CORRESPONDING AUTHOR 

Marta Castrica 

marta.castrica@unimi.it 

 

JOURNAL HOME PAGE 

riviste.unimi.it/index.php/haf 

Abstract 

Agri-food wastes (AFW) and by-products can have the potential to be reprocessed as animal feed 

ingredients (Bampidis, et al., 2006). The aim of this study was to determine the in vitro digestibility 

(IVD), the total phenolic content and the antioxidant capacity of 12 samples of AFW and by-products. 

The IVD was assessed in all samples considered with the method developed by Regmi et al. (2009). 

Moreover, the total phenolic content and the antioxidant capacity were tested using two different 

extraction methods: chemical extraction and in vitro physiological extraction, simulating monogastric 

digestion. Further, the polyphenolic content was assessed by Folin–Ciocalteu assay (Attard, 2013) 

while antioxidant capacity was determined by 2, 2-Azino-bis-3 ethylbenzothiazoline-6-sulfonic Acid 

(ABTS) assay. Soy and wheat samples were included as controls in all the experiments performed. 

The results showed that the IVD values ranged from 80 to 90% DM for AFW and from 66 to 98% DM 

for the by-products. Among AFW and by-products considered, the grape marc exhibited the highest 

polyphenolic content with a value of 4.5% w/w, followed by Camilina sativa cake (1.3%w/w), olive 

pomace (0.7% w/w), AFW (1.3% w/w), orange (1.6% w/w) and strawberry dried (1.3% w/w). The grape 

marc showed a significantly (P<0.05) higher ABTS value (573.6 μmol Trolox equivalent/g) compared 

to the other studied samples. The in vitro physiological extraction yielded high polyphenolic content 

and antioxidant capacity, suggesting that during the digestion the bioaccessibility of phenolic and 

antioxidant compounds was improved. The results obtained in this study indicate that AFW and by-

products are relatively high digestible and they may represent a source of antioxidants and phenolic 

compounds when used as feed. 
 

Acknowledgments: This research was supported by Fondazione Banco Popolare di Lodi. 
 

References 

Attard, E, 2013. A rapid microtitre plate Folin- Ciocalteu method for the assessment of polyphenols. Cent. Eur. J. Biol. 8(1), 48-53. 

Bampidis, V., A., Robinson, P., H, 2006. Citrus by-products as ruminant feeds: A review. Animal Feed Science and Technology. 128, 175-217. 

Regmi, P. R., Ferguson, N. S., Zijlstra R. T, 2009. In vitro digestibility techniques to predict apparent total tract energy digestibility of wheat 

in grower pigs. Journal of Animal Science. 87, 3620–3629 

Valorisation of agri-food wastes and 

 by-products as animal feed:  

digestibility, polyphenolic content and 

antioxidant capacity 

Marta Castrica1*, Carlotta Giromini1, Raffaella Rebucci1,  

Davide Gottardo1, Valentino Bontempo1, Antonella Baldi1 

 

 

 

1 University of Milan, Department of Health, Animal Science and Food Safety, Italy 

 

 

http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en