Blackberries are fruits of great commercial value, but at the same time highly fragile and with reduced shelf-life. Their extreme fragility and susceptibility to mechanical deterioration justifies the need to deepen into technological alternatives that allow prolonging their useful life. The use of edible coatings emerges as a promising alternative to preserve the postharvest quality of blackberries. Natural additives such as antimicrobials, antioxidants, firmness agents or bioactive ingredients can be added into them in order to increase safety and maintain the sensory, nutritional and functional characteristics of minimally processed fruits. The objective of this work was to evaluate the quality of blackberries (Rubus fructicosus var Ouchita) from the first harvest (December) and their behavior during the postharvest, after applying chitosan, alginate and alginate coatings with the addition of vanillin, as an alternative to maintain the quality of the fruits. The first stage of the work was carried out analyzing the fruits at the time of harvest and during 14 days of refrigerated storage without the application of coatings, in order to determine their useful life. In addition, physicochemical and nutritional quality parameters (firmness, soluble solids, titratable acidity, ascorbic acid retention, total polyphenols and antioxidant capacity) were evaluated at 0, 4, 7, 11 and 14 days of storage. Microbiological quality, sensory acceptability and fungal deterioration were also evaluated. In a second stage of the experimental design, the blackberries were treated with different edible coatings and stored under refrigeration (5ºC) to determine their useful life, performing the previously detailed determinations. The results obtained indicated that active edible coatings could be considered as a potential alternative for postharvest preservation that allows maintaining the quality attributes of blackberries and prolonging their marketing period; however, even more research is required to be able to be transferred to fruit and vegetable producers.

Spinach is characterized by having a high water content and different vitamins and minerals. However, this vegetable could have high oxalate and nitrate concentrations and can affect human health if consumed.The aim of this study was to evaluate the nitrogen fertilization effect on the yield, nitrate and oxalic acid content of spinach produced in an autumn-winter cycle under different growing systems. Spinach was grown in soil in a greenhouse and in an open field at the experimental field of the Faculty of Agronomy of the University of Buenos Aires. Soil treatments were 0.50 and 100 kg N.ha-1. Another culture was in substrate (perlite) where nitrogen supply restriction was applied 15 days before harvest. Color, leaf area, harvest index, yield, nitrate and oxalic acid levels were determined for each crop at harvest. Leaves were selected and 60 g were packaged in 31 micron polyolefin bags. Bags were stored in a refrigerated chamber at 5 ºC for 9 days. The nitrate and oxalic acid content of spinachwas also determined at the end of the storage period. Yield and leaf area were higher with 100 kg N.ha-1 without differences between greenhouse and open field. Oxalate content was higher in spinach from the open field, showing the highest value in the case of 100 kg N added, without changes at the end of postharvest period. The maximum nitrate content was 2.7 in greenhouse with 100 kg N.ha-1. The nitrogen restriction reduced the commercial yield, oxalic acid and nitrate content at harvest in perlite. The difference was maintained postharvest, except for the nitrate content.

Internal commercialization and exportation of yerba mate represent an important economic incentive for yerba producers in the Itapúa department, in Paraguay. Favorable conditions for fungal development during the processing and storage of yerba mate can alter the bromatological and commercial quality of the product, with the consequent production of mycotoxins that are harmful to human health. The objectives were to determine the incidence of the genus Aspergillus and the frequency of species belonging to the Nigri and Flavi sections, with potential mycotoxigenic capacity, in Paraguayan yerba mate. Eleven commercial samples obtained from store shelves from Itapúa´s department were processed. The fungal content was quantified in Fungi and Yeast culture media with chloramphenicol, incubated 7 days at 25 ± 2 ° C. The isolates were identified at section and species level by their morphological phenotypic characteristics in three culture media at three different temperatures. The fungal strains of the Aspergillus genus were detected, obtaining 43 isolates, of which 95% belong to the Nigri section and 2.7% to the Flavi section. All the analyzed samples showed contamination by the Aspergillus genera, with 100% incidence of species from the Nigri section and 36% from other sections. A predominance of biseriate subspecies (66%) A. niger var awamori, A. niger var niger, A. fetidus, over uniseriate (34%) A. japonicus var. japonicus and A. japonicus var aculeatus was observed. These results highlight the importance of conducting independent studies on local products, given that each geographic region has its own mycological profile.

Consumption of leafy vegetables is beneficial, however, the ingestion of contaminated food may cause diseases. The objective of this study was to obtain data on microbiological quality of leafy vegetables produced in the Fronteira Oeste region of Rio Grande do Sul. Samples of lettuce, cabbage leaf, arugula and a mixture of parsley and chive were collected, with quantification of total and thermotolerant coliforms by most probable number method and detection of Salmonella sp. using Petrifilm™ Salmonella Express System. A questionnaire was applied to understand the cultivation system of leafy vegetables used in the region: local, type of fertilizer, water source and surroundings.  Results showed high counts of coliforms ranging from 2.21 to 3.38 MNP/g for total coliforms and from 0.60 to 3.38 log MPN/g for thermotolerant coliforms, and 47% (n=16) of prevalence for Salmonella sp. In addition, 100% (n=8) of arugula, 85.7% (n=6) of parsley and chive, 75% (n=6) of cabbage leaf, and 60% (n=6) of lettuce samples were classified as improper for consumption, mainly in the municipalities of São Borja and Alegrete. The use of fertilizer considered organic and untreated water for irrigation and the presence of animals close to the production could be some of the factors involved in this type of contamination. Microbial contamination indicated unsatisfactory hygienic-sanitary quality, which emphasizes the need of good agricultural practices and good handling practices for leafy vegetables in order to reduce health risks to consumers.

The aim of this study was to analyze the impact of different doses of compost obtained from fats waste of dairy industry mixed with a commercial peat-based substrate (CS) in the development of pepper seedlings. The effect of these mixtures on germination was also determined. Fat compost (FC) was obtained by the aerobic composting of sewage mixed with industry prunings (wood chips and grass). In order to check the maturity of compost, and thus, that it can be applied as a substrate, an aqueous extract thereof was prepared and phytotoxicity in seed germination and root development was analyzed. The result indicated 99.7% relative seed germination and 74.10% of germination rate. Different culture media were prepared by mixing 0, 10, 20 and 40% of FC with CS. The results showed that the application of FC on CS respectively produced increased dry matter (DM) of plants. Seedlings germinated and developed in FC 40 reached 250 mg plant-1 DM. The application of FC at germination and seedling growth showed a marked improvement in terms of development in general, DM plant, height / diameter stem, leaf area and the concentration of total chlorophylls.

The postharvest disinfection by applying sanitizers by nebulization could be a promising technology to extend the storage period of fresh strawberries (Fragaria x ananassa Duch.) The objective of this work was to model and optimize the operation of disinfection of fresh strawberries by nebulization with an ecological commercial disinfectant based on peracetic acid (PAA), aiming to reach microbiological reductions and not to alter the general quality, the content of bioactive compounds and the antioxidant capacity of the fruit. The disinfection of fruits of the ‘Camarosa’ variety was studied in a specially designed chamber, varying the concentration (3.4, 20.0, 60.0, 100.0 and 116.6 μL APA 5% per liter of air) and treatment time (5.7, 15.0, 37.5, 60 and 69.3 min). The count reduction of total mesophilic aerobic microorganisms and yeast and molds of nebulized strawberries was greater as PAA concentration and treatment time increased. However, PAA oxidizing properties negatively impacted on anthocyanins and total phenols, vitamin C, antioxidant capacity and color of the fruits, to varying degrees, depending on the spraying conditions. The optimization of fogging operation based on a microbiological reduction target of 2.0 log cycles, maximum retention of bioactive compounds and antioxidant capacity and no change in color, allowed to determine conditions of optimal treatment: 10.1 uL PAA / L air and 29.6 min. Additional experiments at these conditions validated the methodology. This postharvest disinfection treatment would allow obtaining strawberries with microbiological quality up to 7 days at 2ºC without affecting their sensory quality and bioactive properties.

The cultivation of edible and medicinal mushrooms generates large volumes of substrate degraded by fungi (SDF). Mushroom cultivation implies a solid-state fermentation (SSF) with production of fungal metabolites and the consequent biodegradation of lignocellulosic materials. SSF accelerates organic matter mineralization; therefore, at the end of the cultivation cycle, SDH has greater stability than the original substrate. SDF properties depend largely on whether prior to inoculation of the mushroom species, the starting substrate is composted or just decontaminated. In the first case, the cultivated mushroom species are more substrate-sensitive. In the latter, the mushroom species used are more substrate-adaptable, and are the most widely adopted by small and medium-sized producers as well. After mushroom cultivation, SDF is removed from the production site. Henceforth, depending on its further use, certain storage conditions should be observed, and physical and/or chemical conditioning is usually needed. In horticulture, particle size reduction and dilution of excess salts, by mixing with other materials or leaching, are especially required. The aim of this review is to highlight SDF’s potential as a valuable resource. Particularly, the physical and chemical properties of SDF reported in the literature are summarized, and its different uses evaluated in horticultural systems are described. Among these are: substrate for seedlings, soil amendment and biofertilizer.

Vegetables inoculation with Azospirillum sp. enhances seedling growth and crop productivity. In lettuce (Lactuca sativa L.), inoculation with Az39, Pl64 and Pl3 strains of A. brasilense improved seedlings growth. The aim of this work is to evaluate morphological modifications of seedlings when these strains are combined in a formulation. Three trials were carried out using butterhead lettuce cv. Lores (Vilmorin®), performing the inoculation at sowing with a formulation which consisted of 1 x 107 UFC.ml-1 of a mixture of the strains Az39, Pl64 y Pl3 of A. brasilense, using not inoculated plants as control. It was dispensed 1ml of product per cell (1 x 107 UFC per seed). A completely randomized design with 20 replications was used. When plants showed 4 leaves, it was registered shoots, roots and plant fresh and dry weight, root absorption area and lineal length of root, submitting data to analysis of variance. Inoculated plants performed different depending on crop season. Root absorption area increased significantly in one of the three trials, exceeding the control by 27 %. Leaf, root and plant fresh weight were significantly higher in two trials, reaching values 11 %, 20 % and 12 % higher than control plants, respectively. No significant differences were observed on root length or dry weight.

Celery is appreciated for its nutritional value. “Commercial maturity” is established by the size of the plant; however, the antioxidant content has an effect on the nutritional quality and should be considered when defining the time of harvest. The objective was to characterize the antioxidant compounds present in celery stalks in three zones (outer, middle and inner) at different stages of development, to recommend the harvest-time that maximizes nutritional quality. Ascorbic acid (AA) and total phenolic compounds, such as browning potential (PP) and quinones (QT) were meassured. The AA and PP decreased with ripening, following a linear trend in all three areas. The AA and PP were higher in the inner zone, while higher QT was observed in the inner and outer zones, remaining constant with ripening. From a nutritional standpoint, the inner zone is rich in antioxidants, but more prone to damage by changes in color. Zonification could affect the taste, astringency and hardness of each zone, considering the elaboration of minimally processed stalks. Celery plants should be harvested before week 3 (94 days post-transplant) to maintain the nutritional value but considering the potential increase in browning.