Active antifungal packaging is a technological solution for reducing the postharvest losses of fruits and vegetables associated with phytopathogens. Anthracnose (Colletotrichum gloeosporioides) is the principal fungus that causes post-harvest avocado fruit decay. In this study, antifungal sachets filled with oregano oil-starch capsules were prepared, and their active effects were demonstrated on Hass avocado fruits. Oregano oil (31 % of carvacrol) was encapsulated with corn starch by spray drying. Tyvek sachets (4 × 4 cm) filled with 80 (T1) and 160 mg (T2) of oregano oil-starch capsules (99.35 ± 1.86 mg g − 1) were fabricated. The antifungal effects of the sachets were tested in vitro and in vivo using a humidity chamber (90–95 % relative humidity (RH)) on fruits inoculated with anthracnose. The results showed that T1 and T2 inhibited 75.21 ± 2.81 and 100 % in vitro growth of anthracnose at 25 °C for 12 days. Furthermore, Hass avocado fruits stored in a humidity chamber at 25 °C for 6 days showed that only T2 significantly (p < 0.05) reduced the area of lesion produced by artificial inoculation of Hass avocado fruits with anthracnose. On average, the lesion area in the Hass avocado fruits treated with T2 was 13.94 % smaller than that in the control fruit.
MULTIFILE
Semi-closed greenhouses have been developed in which window ventilation is minimized due to active cooling, enabling enhanced CO2 concentrations at high irradiance. Cooled and dehumidified air is blown into the greenhouse from below or above the canopy. Cooling below the canopy may induce vertical temperature gradients along the length of the plants. Our first aim was to analyze the effect of the positioning of the inlet of cooled and dehumidified air on the magnitudes of vertical temperature and VPD gradients in the semi-closed greenhouses. The second aim was to investigate the effects of vertical temperature gradients on assimilate production, partitioning, and fruit growth. Tomato crops were grown year-round in four semiclosed greenhouses with cooled and dehumidified air blown into the greenhouses from below or above the crop. Cooling below the canopy induced vertical temperature and VPD gradients. The temperature at the top of the canopy was over 5°C higher than at the bottom, when outside solar radiation was high (solar radiation >250 J cm-2 h-1). Total dry matter production was not affected by the location of the cooling (4.64 and 4.80 kg m-2 with cooling from above and from below, respectively). Percentage dry matter partitioning to the fruits was 74% in both treatments. Average over the whole growing season the fresh fruit weight of the harvested fruits was not affected by the location of cooling (118 vs 112 g fruit-1). However, during summer period the average fresh fruit weight of the harvested fruits in the greenhouse with cooling from below was higher than in the greenhouse with cooling from above (124 vs 115 g fruit-1).
Prevention of non-communicable diseases through, among other factors, increasing vegetables and fruit (V&F) intake is a cost-effective strategy for risk reduction but requires behavioral change. Such changes in adolescents benefit from their active involvement. The Food Boost Challenge (FBC) was developed using a participatory action research approach to enhance healthy eating behaviors, namely V&F products among adolescents. The FBC is an innovation process, involving adolescents, (peer) researchers, and food system partners, like non-governmental and commercial organizations. In 2021–2022, 34 partners provided both cash and in-kind contributions to join the FBC community. Phase 1 involved 200 students identifying barriers and drivers for consumption of F&V products among 1000 pre-vocational adolescents, aged 12–20 years. In phase 2, student teams submitted innovative ideas, resulting in 25 concepts fitting into ≥1 of 4 routes: (I) innovative technology for a healthy diet, (II) new food products/concepts for adolescents, (III) hotspots improving the F&V product experience, and (IV) new routes to market. In phase 3, consortia of adolescents, students, and partners were formed to develop 10 selected concepts into prototypes, and phase 4 offered teams a national platform. Results show that the FBC resonates with all stakeholders, generating valuable insights to increase F&V intake. Prototypes in all four routes have been developed. Additionally, other regions in the Netherlands have adopted the FBC approach. Overall, the FBC is an approach that transforms ideas into actionable measures and shows potential to be adapted to promote various healthy eating behaviors among school students.
Chemical preservation is an important process that prevents foods, personal care products, woods and household products, such as paints and coatings, from undesirable change or decomposition by microbial growth. To date, many different chemical preservatives are commercially available, but they are also associated with health threats and severe negative environmental impact. The demand for novel, safe, and green chemical preservatives is growing, and this process is further accelerated by the European Green Deal. It is expected that by the year of 2050 (or even as soon as 2035), all preservatives that do not meet the ‘safe-by-design’ and ‘biodegradability’ criteria are banned from production and use. To meet these European goals, there is a large need for the development of green, circular, and bio-degradable antimicrobial compounds that can serve as alternatives for the currently available biocidals/ preservatives. Anthocyanins, derived from fruits and flowers, meet these sustainability goals. Furthermore, preliminary research at the Hanze University of Applied Science has confirmed the antimicrobial efficacy of rose and tulip anthocyanin extracts against an array of microbial species. Therefore, these molecules have the potential to serve as novel, sustainable chemical preservatives. In the current project we develop a strategy consisting of fractionation and state-of-the-art characterization methods of individual anthocyanins and subsequent in vitro screening to identify anthocyanin-molecules with potent antimicrobial efficacy for application in paints, coatings and other products. To our knowledge this is the first attempt that combines in-depth chemical characterization of individual anthocyanins in relation to their antimicrobial efficacy. Once developed, this strategy will allow us to single out anthocyanin molecules with antimicrobial properties and give us insight in structure-activity relations of individual anthocyanins. Our approach is the first step towards the development of anthocyanin molecules as novel, circular and biodegradable non-toxic plant-based preservatives.
Horticulture crops and plants use only a limited part of the solar spectrum for their growth, the photosynthetically active radiation (PAR); even within PAR, different spectral regions have different functionality for plant growth, and so different light spectra are used to influence different properties of the plant, such as leaves, fruiting, longer stems and other plant properties. Artificial lighting, typically with LEDs, has been used to provide these specified spectra per plant, defined by their light recipe. This light is called steering light. While the natural sunlight provides a much more sustainable and abundant form of energy, however, the solar spectrum is not tuned towards specific plant needs. In this project, we capitalize on recent breakthroughs in nanoscience to optimally shape the solar spectrum, and produce a spectrally selective steering light, i.e. convert the energy of the entire solar spectrum into a spectrum most useful for agriculture and plant growth to utilize the sustainable solar energy to its fullest, and save on artificial lighting and electricity. We will take advantage of the developed light recipes and create a sustainable alternative to LED steering light, using nanomaterials to optimally shape the natural sunlight spectrum, while maintaining the increased yields. As a proof of concept, we are targeting the compactness of ornamental plants and seek to steer the plants’ growth to reduce leaf extension and thus be more valuable. To realize this project the Peter Schall group at the UvA leads this effort together with the university spinout, SolarFoil, whose expertise lies in the development of spectral conversion layers for horticulture. Renolit - a plastic manufacturer and Chemtrix, expert in flow synthesis, provide expertise and technical support to scale the foil, while Ludvig-Svensson, a pioneer in greenhouse climate screens, provides the desired light specifications and tests the foil in a controlled setting.
