Mediterranean Institute for Agriculture, Environment and Development

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1-Methylcyclopropene and lemongrass essential oil nanocoatings effect on the preservation of cold stored ‘Rocha’ pear

Publication . Gago, Custódia; Guerreiro, Adriana; Cruz, Sandra; Martins, Nuno; Cabrita, Maria João; Miguel, Maria; Faleiro, Maria Leonor; Antunes, Maria Dulce

The effects of coating 'Rocha' pear with alginate-based nanoemulsions enriched with lemongrass essential oil (LG) was evaluated and compared to the usual 1-MCP treatment. Fruit were treated with 1-MCP (312 nL L-1) or coated with nanoemulsions: sodium alginate 2 % (w/w) + lemongrass essential oil 1.25 % (w/w) (LG 1.25 %) or lemongrass essential oil 2.5 % (w/w) (LG 2.5 %). Then, fruit were stored at 0 degrees C and 90-95 % relative humidity (RH), for eight months. Fruit samples were collected at harvest and after two, four, six and eight months of cold storage, and then transferred to shelf-life at 22 degrees C. Upon removal and after 7 d shelf-life, fruit symptoms of superficial scald and internal browning, ethylene production, color CIE (L*, hue), firmness, soluble solids content (SSC), titratable acidity (TA), weight loss, electrolytic leakage (EL), antioxidant activity and fatty acids of pear peel, microbial growth and sensory analyses were evaluated. Coatings and 1-MCP reduced fruit color evolution and preserved better firmness than control. Coatings and 1-MCP did not affect SSC and TA. Treatments did not influence the sensory quality. Microbial growth was within the safety limits in all treatments. Treatments with 1-MCP and LG-nanoemulsions were similarly efficient to reduce superficial scald, nevertheless the LG-nanoemulsions showed higher internal disorders after 8 months of storage and LG 2.5 % had higher decay at the same period, similar to control. 1-MCP treated fruit had the lowest softening rate after shelf-life up to 4 months and LG 2.5 % showed higher weight loss. Also, ethylene production was higher in control and LG 1.25 % up to 6 months plus shelf-life, while after 8 months there was no difference among treatments. This study suggests that 1-MCP is the most efficient for preserving quality of 'Rocha' pear for 8 months, while up to 6 months the best effect is obtained with LG 1.25 % nanocoatings.

2022Journal article

Open Access

Carob: A mediterranean resource for the future

Publication . Martins-Loução, Maria Amélia; Correia, Pedro José; Romano, Anabela

For centuries, the carob tree (Ceratonia siliqua L.) has contributed to the economy of the Mediterranean basin, mainly as food for livestock. Nowadays, the value of the carob tree extends far beyond its traditional uses, encompassing a wide range of industries and applications that take advantage of its unique properties and nutritional benefits. Despite its high industrial demand and European indications, there has been a 65% reduction in the area cultivated throughout the Mediterranean area in the 21st century. Given the threats posed by climate change, including reduced water availability and nutrient-depleted soils, there is a growing need to focus on this crop, which is well placed to cope with unpredictable weather. In this review, we use a bibliographic search approach to emphasise the prioritisation of research needs for effective carob tree exploitation. We found enormous gaps in the scientific knowledge of this under-utilised crop species with fruit pulp and seeds of high industrial value. Insufficient understanding of the biology of the species, as well as inadequate agronomic practices, compromise the quantity and the quality of fruits available to the industry. In addition to industrial applications, carob can also be used in reforestation or restoration programmes, providing a valuable crop while promoting biodiversity conservation and soil restoration. The carbon sequestration potential of the trees should be taken into account as a promising alternative in fighting climate change. This bibliographic search has highlighted clusters with different knowledge gaps that require further research and investment. The carob tree has untapped potential for innovation, economic development, and environmental sustainability.

2024-04-25Journal article

Open Access

Comparing the response of Citrus ×limon and Citrus ×sinensis to Trioza erytreae infestation using a proteomic approach

Publication . Magalhães, Tomás; Dandlen, Susana; L, Anjos; Power, Deborah; Pereira, José Alberto; Duarte, Amilcar; Marques, Natália

Citrus production is on high alert because of the devastating disease Huanglongbing (HLB), caused by the bacteria Candidatus Liberibacter spp.. With no viable treatment, current management practices rely on the control of its vectors, such as the African citrus psyllid,Trioza erytreae (Del Guercio 1918), which is already in the Mediterranean region (Portugal and north of Spain). This vector develops better in some citrus hosts, with Citrus ×limon described as the preferred host. To better understand the molecular response of citrus hosts to the psyllid, the phloem proteome of lemon (Citrus ×limon) and orange (Citrus ×sinensis) plants infested with T. erytreae was compared with equivalent non infested plants. Infestation was established with isolated plants by exposing them to 10 T. erytreae adults. Nymphs of T. erytreae at the 4-5th instar stage were removed from plants and infested leaf phloem was extracted. In control plants phloem was extracted from leaves of a similar size and developmental stage. The experiment was done under controlled conditions of temperature, light and humidity. Phloem was analyzed by nanoLC-MS/MS. A total of 48 and 1265 differentially abundant proteins (DAP) were identified in lemon and orange plants, respectively, with 18 proteins common to both species. The topmost enriched GO terms retrieved for upregulated proteins in lemon plants were assigned to organic acid and cellular amino acid metabolic processes. The topmost enriched GO terms in orange plants included organonitrogen compound metabolic process, cellular component assembly, establishment of protein localization, while downregulated terms were associated with carbohydrate metabolic process. This study revealed that T. erytreae infestation promoted distinct modifications in the phloem proteome of lemon and orange plants. This work is part of a group of studies that focus on this insect-plant interaction that aims for more informed and improved T. erytreae control.

2022-11-08Conference object

Restricted

Sensory evaluation and spectra evolution of two kiwifruit cultivars during cold storage

Publication . Afonso, Andreia M.; Guerra, Rui; Cruz, Sandra; Antunes, Maria D.

Kiwifruit consumption has increased due to its rich nutritional properties. Although ‘Hayward’ continues to be the main cultivar, others, such as yellow fleshed ‘Jintao’, are of increasing interest. The objective of this research was to evaluate the acceptability and storage performance of these two cultivars. Sensory evaluation of green ‘Hayward’ and yellow ‘Jintao’ kiwifruit were performed along cold storage for three seasons/years to follow the organoleptic characteristics through ripening, as well as the acquisition of their spectra by Vis-NIR. For ‘Jintao’ were performed two sensory evaluations per year at 2.5- and 4.5-months’ storage and for ‘Hayward’ at 2.5-, 4.5- and 5.5-months’ storage. The nonparametric Mann–Whitney test and Kruskal–Wallis ANOVA were performed to test the significant differences between the mean ranks among the storage time. A non-metric multidimensional scaling plot method using the ALSCAL algorithm in a seven-point Likert scale was applied to determine the relationships in the data, and a new approach using the receiver operating characteristic (ROC) analysis was tested. The last revealed that, for both cultivars, sweetness, acidity and texture were the variables with better scores for General flavor. Aroma was also important on ‘Jintao’. A strong correlation between soluble solids content (SSC) and reflectance was found for both cultivars, with the 635–780 nm range being the most important. Regarding firmness, a good correlation with reflectance spectra was observed, particularly in ‘Hayward’ kiwifruit. Based on these results, Vis-NIR can be an objective alternative to explore for determination of the optimum eating-ripe stage.

2023-07-06Journal article

Open Access

Valorization of cork stoppers, coffee-grounds and walnut shells in the development and characterization of Pectin-Based composite films: Physical, barrier, antioxidant, genotoxic, and biodegradation properties

Publication . Cruz, Rui; Rainer, Bernhard; Wagner, Isabella; Krauter, Victoria; Janalíková, Magda; Vicente, António A.; Vieira, Jorge M.

The development of sustainable materials from the valorization of waste is a good alternative to reducing the negative environmental impact of plastic packaging. The objectives of this study were to develop and characterize pectin-based composite films incorporated with cork or cork with either coffee grounds or walnut shells, as well as to test the films’ genotoxicity, antioxidant properties, and biodegradation capacity in soil and seawater. The addition of cork, coffee grounds, or walnut shells modified the films’ characteristics. The results showed that those films were thicker (0.487 ± 0.014 mm to 0.572 ± 0.014 mm), more opaque (around 100%), darker (L* = 25.30 ± 0.78 to 33.93 ± 0.84), and had a higher total phenolic content (3.17 ± 0.01 mg GA/g to 4.24 ± 0.02 mg GA/g). On the other hand, the films incorporated only with cork showed higher values of elongation at break (32.24 ± 1.88% to 36.30 ± 3.25%) but lower tensile strength (0.91 ± 0.19 MPa to 1.09 ± 0.08 MPa). All the films presented more heterogeneous and rougher microstructures than the pectin film. This study also revealed that the developed films do not contain DNA-reactive substances and that they are biodegradable in soil and seawater. These positive properties could subsequently make the developed films an interesting eco-friendly food packaging solution that contributes to the valorization of organic waste and by-products, thus promoting the circular economy and reducing the environmental impact of plastic materials.

2024-04-11Journal article

Open Access