Bioactive compound composition of pomegranate fruits removed during thinning

Thinning consists of reducing fruit load at immature stage and thus allowing remaining fruits to develop to their maximum size and quality. The waste material produced during this farming practice was characterised in 9 pomegranate cultivars, by evaluating: weight, size, maturity index, pH, organic acids and sugars profiles, contents of minerals, punicalagin, and ellagic acid, total polyphenols and antioxidant activity. Citric and quinic were the main organic acids. Potassium was the predominant mineral, reaching up to 11 g kg⁻¹ dry weight (dw). Total polyphenol content ranged from 777 to 1660 g GAE kg⁻¹ dw, α-punicalagin from 101 to 195 and β-punicalagin from 80.1 to 111 g kg⁻¹ dw. The antioxidant activity was assessed by three methods and its values varied from 2923 to 4486 for ABTS, from 3153 to 4685 for FRAP, and from 2075 to 2934 mmol Trolox kg⁻¹ dw for DPPH. Pomegranate thinning fruits, especially sour-sweet cultivars, are rich in bioactive compounds, with a potential use in the food, chemical and pharmaceutical industries.