New portable optical sensors for the assessment of winegrape phenolic maturity based on berry fluorescence

Grape phenolic maturity is usually assessed by destructive wet chemistry in the laboratory. Yet, for precision agriculture or continuous monitoring of maturation, more rapid and non-destructive methods are needed. Therefore, in addition to measurements of fruit colour, a new optical method was recently proposed. It is based on the screening of fruit chlorophyll fluorescence that allows both flavonol and anthocyanin contents of intact berry skin to be measured. Here, we present the first results obtained with two commercial devices, Dualex FLAV™ and Dualex ANTH™, and a prototype, Multiplex, all based on this new method. We found that the non-contact optical sensor Multiplex has strong potential for an application in the vineyard for precision viticulture or for crop evaluation at the weighbridge.