Nowadays, the environmental footprint of a process has become an important aspect to be considered in each human activity from industrial production to logistics. Despite this increased awareness, environmental friendliness is a quite new aspect in the IT sector and even less considered in the field of recommendation systems. Bundle recommendation aims to generate bundles of associated products that users tend to consume as a whole under certain circumstances, and poses additional challenges in terms of environmental friendliness. Nevertheless, current bundle recommendation systems fail to consider the environmental impact of the product bundle when generating recommendations.

We introduce a new preference-based approach for bundle recommendation exploiting the Choquet integral. This allows us to formalize preferences for coalitions of environmental-related attributes, thus recommending product bundles accounting for synergies among product attributes. An experimental evaluation on a dataset of local food products in Northern Italy shows how the Choquet integral allows to naturally formalize a sensible notion of environmental friendliness, and that standard approaches based on weighted sums of attributes end up recommending bundles with lower environmental friendliness even if weights are explicitly learned to maximize it.