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Roots encounter cinnamic acid and its hydroxylated derivatives that are commonly found in soils. However, root systems consist of different root types with different morphological and physiological characteristics. Very little is known about the responses and adaptation mechanisms of the root types to cinnamic acid and its hydroxylated derivatives. In this study, the morphological and physiological responses of different maize root types exposed to different concentrations of t-cinnamic, ferulic, caffeic or p-coumaric acids were investigated. The results showed that the effects of allelochemicals were dependent on concentration, chemical structure, root type and process considered. In particular, t-cinnamic acid was characterized by higher allelopathic activity when compared with its derivatives, where a hydroxyl or methyl groups were present in aromatic ring. Among root types it was possible to delineate the following tolerance hierarchy: primary [ seminal [ nodal [ lateral of the primary = lateral of the seminal roots. Moreover, primary and seminal roots showed a different strategy to cope the chemical stress by either increasing or decreasing specific root length. Finally, an electrophysiological approach identified an involvement of proton pump activity and consequently a decrease in nitrate uptake.

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The whiteness of shredded carrots is generally caused by enzymatic reactions after removal of natural protection during the minimal processing. Moreover, the use of chlorinated solution in sanitizing step of processing, promotes the formation of halogenated by-products, with correlated environmental and health risks in processing areas. This study investigated the effect of different acidic solutions on the quality of shredded carrots during the storage at two refrigerated temperatures (4°C and 7°C), as alternative agents to chlorine in food industry. Carrots dipped in 1.5% citric acid solution did not present colour variation at both storage temperatures. Moreover they showed the lowest microbial charge after processing and during storage at 4°C. Carrots dipped in 0.5% citric acid ? 0.05% ascorbic acid ? 0.05% calcium chloride evidenced lower PAL and POD activities during the storage respect to the other tested samples. Therefore, the dipping of shredded carrots in acidic solutions, as alternative sanitizers to chlorine, contributed to preserve their quality, also controlling the whiteness index of carrots' surface. In particular, the dipping in 1.5% citric acid extended the shelf life of shredded carrots up to 14 days of storage at 4°C.