Combining Blue Light and Yellow Curcumin to Obtain a “Green” Tool for Berry Preservation against Bacterial Contamination: A Preliminary Investigation

Abstract

Background: According to recent studies, tens of millions of tons of fruit are wasted each year in Europe in primary production and home/service consumption. Among fruits, berries are most critical because they have a shorter shelf life and a softer, more delicate, and often edible skin. Curcumin is a natural polyphenolic compound extracted from the spice turmeric (Curcuma longa L.) which exhibits antioxidant, photophysical, and antimicrobial properties that can be further enhanced by photodynamic inactivation of pathogens when irradiated with blue or ultraviolet light. Materials and methods: Multiple experiments were performed in which berry samples were sprayed with a complex of β-cyclodextrin containing 0.5 or 1 mg/mL of curcumin. Photodynamic inactivation was induced by irradiation with blue LED light. Antimicrobial effectiveness was assessed with microbiological assays. The expected effects of oxidation, curcumin solution deterioration, and alteration of the volatile compounds were investigated as well. Results: The treatment with photoactivated curcumin solutions reduced the bacterial load (3.1 vs. 2.5 colony forming units/mL (UFC/ml) in the control and treated groups; p-value = 0.01), without altering the fruit organoleptic and antioxidant properties. Conclusions: The explored method is a promising approach to extend berries’ shelf life in an easy and green way. However, further investigations of the preservation and general properties of treated berries are still needed.

Encapsulation in Oxygen-Loaded Nanobubbles Enhances the Antimicrobial Effectiveness of Photoactivated Curcumin

“…These results further confirm the antibacterial effectiveness of the photoactivated curcumin-loaded NBs which were already proposed for food preservation [6,7], in particular for berries. In this contest, the affordable cost of the materials and the fact that most of the supermarket refrigerated benches are equipped with white light LED, which could, at least partially, elicit photodynamic curcumin activation, makes this approach readily applicable to the market.…”

“…Food contamination has already been the subject of promising microbial photodynamic inactivation (PDI) applications [5]. Our research team has also studied the use of photoactivated curcumin to prevent bacterial fruit contamination [6,7]. This strategy is also promising for reducing the risk of infections during wound healing and with bedsores [8][9][10][11].…”

Curcumin Electrochemistry—Antioxidant Activity Assessment, Voltammetric Behavior and Quantitative Determination, Applications as Electrode Modifier

“…Photoactivated CU encapsulated in β-CD was used for the antibacterial treatment of berries, increasing their shelf life without changing their organoleptic properties [26], while recent studies emphasized that CU-NPs, even at low concentrations, improved soybean growth and could be employed as fertilizer [27]. CU loaded into a zein/shellac-based composite food packaging film conferred antioxidant properties, inhibited E. coli, and the color change with pH variation enabled the monitoring of the food freshness [28].…”