The hard-shelled seed industry plays an important role in the global agricultural economy. As a result of nut industrialization, considerable amounts of by-products and residues are produced year by year, burnt as fuel or discarded as non-valued waste, by-passing a potential source of valuable compounds or features. Over the last decade nutshells have received great interest due to their lignin concentration and their antioxidant, physical and mechanical features. It was found that these properties vary among cultivars, latitude and localities of plantation. On the other hand, there is inconsistences regarding to mechanical and some biochemical properties of both nutshells, which aimed to explore the status of potential hazelnut and walnut shells appli-cations into sustainable circular bio-economy chains. Hence, this review deals with the recent scientific literature on their chemical composition as well as their functional applications as an approach to sustain the utilization of the main by-product derived from the nut-industry.

Chestnut is an interesting productive alternative for farmers in Southern Chile. However, cli-matic variability with the occurrence of late spring and early summer frost have cause damages on young trees. Glycine‒betaine (GB) spraying on shoots of sensitive chestnut induce an increase in tolerance during subsequent chilling stress. Experiment was performed on three years-old trees (cultivar Cittá di Castello) conducted in a leader training system and sprayed with com-mercial GB (120 g hL‒1). In summer trees treated with GB showed a better recovery after the frost (‒2.34°C) occurrence for 3.5 h compared to the control. Whereas trees obtained a 28% greater growth of central axis than untreated control (January). The trunk diameter measured in January showed the highest value under GB (27.2mm) compared with the control (25.7 mm). The GB ap-plication increased by 50 and 47% highest fresh and dry weight respectively in leaves. Under GB trees reached a 28% higher net photosynthesis (AN) compared to the AN in control (11.93 µmol CO2 m‒2 s‒1). Moreover, achieved higher stomatal conductance and transpiration rate was 44 and 31% with GB compared to control trees respectively. Antioxidant performance was differentially affected by GB activating non-enzymatic mechanisms and caused a reduced lipid peroxidation. Glycine‒Betaine has become as an interesting agronomic tool that aimed to increase tolerance to environmental stresses such as low temperatures that cause damage to herbaceous shoots and leaves in young chestnut trees.