Effect of growing substrate composition and storage temperature on quality parameters of a red mini plum tomato (Solanum lycopersicum L. ‘Solarino’)

Fertilizers from agri-food waste such as biochar (BC) and wood distillate (WD) are considered an innovative solution in agriculture, to improve fruit quality and promote the circular economy. However, the effect of these products on post-harvest parameters of tomato fruits needs to be better investigated. Due to its short shelf-life and susceptibility to mechanical damage, huge post-harvest losses are witnessed in several tomato varieties. This study aimed to evaluate, in a soilless system, the influence of substrate composition on the shelf life of a tomato red mini plum variety (cv. Solarino). Specifically, BC and WD (3ml/l) were added to a coconut fiber substrate, alone or in combination (2¼, 5¼, 2¼+WD, 5¼+WD), and harvested fruits were stored at room temperature (RT) and at 4°C. Fruit quality parameters were monitored once a week for two weeks. As expected, fruits stored at 4°C evidenced a decay slower than those at RT, and they seemed to suffer less the effect of the substrate composition, as observed, for weight. Interesting results were observed within fruits stored at RT, Total Soluble Solid content showed, in control samples, after one week of storage, an increase of 13%, and then, in the second week, a decrease of 15%. On the other hand, in fruits from treated plants, increment and reduction percentages were markedly lower (on average +6.9% and -3.4%). In addition, growing substrate composition influenced the antioxidant activity, during the fruit storage, with a more marked increase registered for fruits from 2% biochar enriched substrate. Preliminary results reported in this study set the base for further investigation into how adding agri-food-derived fertilizers in the growing substrate could influence post-harvest quality characteristics of tomato fruits and consequently, improve their shelf-life.