Cristina Patanè

Use in Vivo of Natural Anti-browning Agents Against Polyphenol Oxidase Activity in Minimally Processed Eggplant

Plant polyhenol oxidase (PPO, EC 1.14.18.1) is responsible along with other oxidases for the enzymatic browning reaction occurring during handling, storage and processing of vegetables. This work aimed at assessing the efficacy in vivo of some natural anti-browning agents in minimally processed eggplants. They were collected, washed, diced, submitted to dipping with inhibitors (L-ascorbic, benzoic, citric, ferulic and L-glutamic acid) at three concentrations (0.2, 0.5 and 1 %) and packed in ordinary atmosphere bags (PET), covered by a double barrier film and refrigerated for 7 days (4.0 ± 0.5 °C, 95 % RH). The enzymatic activity was inhibited by addition of all anti-browning agents tested. At t=7 the greatest reduction in PPO activity was observed at the highest concentrations (0.5 and 1 %) of the inhibitors in the following order: ferulic acid (-43 %), L-glutamic acid (-32 %), citric acid (-27 %), L-ascorbic acid (-21 %) and benzoic acid (-15 %). These positive effects were also translated in terms of browning index, demonstrating the efficacy of the anti-browning treatments studied to extend the shelf-life of minimally processed eggplants.

Effects of calcium carbonate application on physiology, yield and quality of field-grown tomatoes in a semi-arid Mediterranean climate

Abstract. Foliar and fruit application of mineral particle films is considered to reduce damage from heat and water stress significantly in many horticultural crops. Sprays with new formulations consisting of suspensions of calcium carbonate can have beneficial effects on vegetable crops, including tomato. We assessed the effects of a calcium carbonate suspension on physiology, yield and some quality aspects of a tomato crop under three levels of deficit irrigation (I50, moderate; I25, moderate–severe; I0, severe) in the semi-arid climate of eastern Sicily. Leaf transpiration was significantly reduced by 47% (late June) and 58% (early July) in plants treated with the suspension. Late in the growing season, sprayed leaves were ∼1°C cooler than unsprayed (control) leaves. Spray treatment resulted in a higher marketable yield (+12%) than the control under I50, and fruit quality was significantly improved under I0. Treated tomatoes exhibited better firmness (+24%), higher contents of vitamin C (+15%) and total phenols (+12%), and higher antioxidant activity (5–7%) than untreated tomatoes. Application of calcium carbonate minimised fruit losses under I50 while ensuring great water saving and improving the nutraceutical properties of fruits. These aspects make the technology an environmentally friendly tool to improve crop sustainability and nutritional quality in tomato.