Beyond Beer: Hop Shoot Production and Nutritional Composition under Mediterranean Climatic Conditions

Abstract

For hop growers, surplus shoots are generally a useless by-product of cultivation. Conversely, they may represent a valuable resource due to rising interest towards healthy and traditional foods. A field trial was carried out in Central Italy to characterize shoot production (number of emerged shoots, shoot fresh weight, marketable shoot yield, and shoot diameter) of three commercial hop cultivars (Cascade, Challenger, and Hallertauer Magnum) and to survey shoot proximate composition (ash, ether extract, crude protein, and crude fiber). Green shoots were harvested when they were from 20 to 40 cm in length. The results from two years showed that there was significant difference among the varieties and between growing seasons, both for yield traits and for nutritional composition. H. Magnum showed the highest marketable shoot yield (152 g per plant, two-year mean), while Cascade had the best proximate composition. The number of emerged shoots per plant varied from 62.5 of Cascade to 84.3 of H. Magnum over a two-year average. Marketable shoot yield showed a positive relationship with number of shoots and average shoot fresh weight, while no significant correlation was found with shoot diameter. Hop shoots proved to be a low-fat food (ether extract from 2 to 6% dry matter (DM)) with high protein (from 22 to 30% DM) and fiber content (from 10 to 16% DM).

Keywords

• hop
• <i>Humulus lupulus</i> L.
• shoot yield
• proximate composition
• Cascade
• Challenger