Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Films made from a mixture of Chayotextle starch-Gelatin (SG) were prepared in concentrations of SG13, SG22 and SG31 respectively. Two controls were considered; gelatin (G) and starch films (S). Glycerol was added as a plasticizer to all treatments at 2%. G treatment presented higher elasticity, permeability and solubility in comparison to those treatments using starch. FT-IR showed that both ingredients gelatin and starch respected their molecular spaces. However, their contribution was relevant for the formation of the matrix of films. The lowest percentage of crystallinity appeared in S films with 30.8%. This value increased up to 48.5 % in the G treatment. The variation of ratios in the mixture gelatin-starch resulted in different degrees of structural composition and these changes could be configured, adapted and applied to the requirements of the food engineering, pharmaceutical, and biomedical industry.

Nopal (Opuntia gosseliniana) is considered a food product of interest due to its functional properties, including its antioxidant activity. The objective of this work was to evaluate the physical-chemical properties (color, pH and total soluble solids), antioxidant activity (DPPH, ABTS and FRAP), content of total phenols and flavonoids and betalain content of ethanolic extracts of nopal in two stages of coloration: green and purple. The highest values for total phenols and flavonoids were found in the purple samples, with values of 2.31 mg EAG/gps and 3.06 mg EQ/gps, respectively. Similarly, in the antioxidant activity (in the three techniques used) and betalain content, higher values were obtained in the purple color stage. Therefore, this species of cacti could be a potential source of antioxidants and pigments of agroindustrial interest.

The effect of seasonality on the microbiological and physicochemical quality of goat milk produced at the center of the Veracruz state, Mexico, was evaluated. Milk from different goat production units (Coatepec, Perote and Tatatila) during the rainy, dry and windy seasons were evaluated. The contents of aerobic mesophiles, total coliform Eschericha coli, Staphylococcus aureus, Salmonella ssp. and Brucella sp. as well as protein, fat, lactose, non-fat solids, density and acidity. The microbiological results determined the absence of Eschericha coli, Staphylococcus aureus, Salmonella spp. and Brucella sp. in the analyzed milks. The effect of the interaction season of the year per production unit per type of milk showed that 50 % of the milk (raw and pasteurized) produced in the windy and rainy seasons presented the highest contents of aerobic mesophiles and total coliforms. The effect of the interaction unit of production by type of milk showed the highest content of non-fat solids, proteins, lactose and density due to the use of different forages such as mulberry, orange peel, Taiwan grass, alfalfa and corn stover. The highest fat contents were found in the production units of Coatepec and Tatatila.

The overuse of pesticides, landscape fragmentation and poor environmental management practices have contributed to the drastic decline of Neotropical unique biodiversity. Parasitoid wasps are widely used as biological control agents, however little is known about the effects of land use and degradation on parasitoid species richness and abundance. This work explores how parasitoid species richness is affected by agroecosystems in which plant diversity is limited (crops; crops adjacent to secondary vegetation). It was found that there is no direct effect of plant diversity in the group of parasitoids studied; however, the number of specialist species (koinobionts) was high, which indicates that diversified  agroecosystems probably function as remnants of natural habitat. Future research could help further understand the extent to which landscape fragmentation and plant diversity may alter host-plants interactions and parasitism strategies.

The sweet potato (Ipomoea batatas L.) is a species of economic importance, because it contributes to the food security of millions of people. However, in Colombia, this specie is underutilized, being cultivated in an artisanal way in the Caribbean region. The objective of this study was to evaluate the agronomic characteristics of sweet potato germplasm, under the agro-environmental conditions of the department of Valle del Cauca, Colombia. Twentynine genotypes were sown using a randomized complete block design and 27 genotypes, for use as parents in a single plot and evaluate the production of sexual seed for genetic recombination processes. A differential response was found between the evaluated genotypes, the genotype 1115-200_BOL exhibited the highest total and first category tuberous roots yield, 64.9 t ha-1 and 52.7 t ha-1, respectively: showing high percentage of first category tuberous roots (81 %). Genotypes 0615-070_COR, 1215-227_BOL and the Agrosavia Aurora variety showed abundant production of reproductive structures. In general, all these traits suggested that it is possible to establish sweet potato breeding processes as well as it insertion as alternative crop, under the agri-environmental conditions of the Valle del Cauca. In addition, the 1115-200_BOL and 1215-232_SUC genotypes were identified as possible commercial cultivars for this region of Colombia.

The state of Zacatecas ranks first in the production of rainfed beans in Mexico. Due to the economic and food security repercussions, it is important to predict yields, production and harvested area, as well as to know the climatological variables that have the greatest effect on bean cultivation. The objectives of the present work were 1) to develop ANN models for the prediction of the harvested area, yields and production of rainfed beans in the state of Zacatecas, using data on maximum and minimum air temperature, precipitation and evaporation during the period 1988-2019. 2) to determine the input variables that have the greatest influence on bean production and yield through sensitivity analysis. Due to the limited availability of climatic data, the Climatol library of the R statistical package was used to fill in missing data. The results show that the RNA models capture the influence of climate on bean production, with an overall efficiency of 0.89 for Rto and 0.86 for SC. The production was estimated using the outputs, Rto and SC, from RNA models and an R2 =0.80 was obtained. According to the sensitivity analysis, Evaporation of the cycle is the most important variable in predicting yield, while precipitation in August (Pp_Ago) and minimum temperature (Tmin) had a greater influence on production.  

The use of edible films is a technology to extend the shelf life of food. The addition of silver nanoparticles (AgNPs) could improve the performance of edible films and avoid the growth of microorganisms that could affect food. The objective was to elaborate and characterize AgNPs by green synthesis and to evaluate the effect of their addition on the mechanical and barrier properties of films formed from Cajanus cajan protein and Tamarindus indica seed gum. An aqueous extract of Annona muricata leaves was used for green synthesis. Three films were developed containing AgNPs, aqueous extract of Annona muricata leaves and water (control). Films were evaluated by their water vapour permeability (WVP), color, opacity and mechanical properties. The AgNPs increased twice the Young's module (0.0675 MPa) and the tensile strength (2.84 MPa) in relation to control film. Moreover, the AgNPs influenced also the color and opacity of the films. However, no differences were observed in the WVP. The addition of AgNPs to films, could be an option to increase the shelf life of foods.

Selenium (Se) is considered a beneficial element for plants; however, high concentrations can cause physiological and morphological disorders. The objective of the study was to identify the concentration and application method of Se that allow obtaining quality seedlings in pepper cultivation, therefore, two experiments were established under greenhouse conditions cultivated in nutrient solution. In experiment 1, for root application, seedlings were grown in a nutrient solution enriched with Se in the form of Na3SeO4 at concentrations of: 0.0, 1.0, 2.5, 5.0 and 10.0 μM. In experiment 2, for foliar application, the seedlings were sprayed with Se in the form of Na3SeO4 at concentrations of 0, 5, 10, 25 and 50 μM. In each experiment, a completely randomized experimental design with five replications per treatment was used. The supply of 1 and 5 μM of Se through root and foliar application, respectively, stimulated the growth of pepper seedlings, similarly, the presence of Se in both application methods increased the concentration of photosynthetic pigments in leaves. Se improved seedling quality by inducing favorable responses in growth and concentration of photosynthetic pigments.

Tagetes is a group of plants commonly known as cempasúchil or “flower of the dead”, which are mainly recognized for their use in the food industry, ornamental horticulture, therapeutic herbalism and culture. Tagetes coronopifolia and terniflora are two species plants of this genus, which are used in crop rotation to control phytopathogenic nematodes. In the curent work, 581 strains were isolated from samples of rhizosphere soil, soil attached to the root and the interior of the root at 30, 60, 90 and 120 days of growth, in greenhouse cultures. From the total isolated rhizobacteria strains, 22 presented antagonistic activity to Fusarium sp. and 53 to Stenocarpella maydis, both. pathogenic fungi in corn, while 37 strains showed antagonism to the pathogenic bacteria Clavibacter michiganensis subsp michiganensis. According to the percentage of inhibition of the phytopathogens, 10 rhizobacteria were selected for molecular identification using a fragment of approximately 1484 bp of the 16SrDNA gene. The similarity analysis using the NCBI BLAST tool, showed that the rhizobacteria belong to the genera Bacillus and Pseudomonas, which are used as biocontrol agents.

Papaya is a climacteric fruit that has a short shelf life. An alternative to extend the shelf life of this fruit is the use of coatings. Therefore, the objective of this study was to evaluate the effect of the coating based on alginate extracted from Sargassum fluitans added with silver nanoparticles on the shelf life of papaya (Carica papaya L. var. Maradol). Silver nanoparticles (NpAg) were obtained by green synthesis. Papaya fruits, in degree of maturity 3, were coated with three solutions: solution A (2.49 % alginate), solution B (2.49 % alginate and 1.1 mg NpAg/mL) and group control (water). The fruits coated and stored for 15 days at 25 °C and 75 % of relative humidity. The fruits coated with solution 1 and 2 maintained optimal values of firmness (6.9 and 6.6 MPa), total soluble solids (11.1 and 11.06 °Brix) and ascorbic acid content (22.31 and 23.02 mg AA/g pulp) during 6 days more than control. The coating of sodium alginate extracted from S. fluitans added or not with NpAg retarded the maturation of the papaya. This technology allowed to prolong the shelf life of papaya at 25 °C without refrigeration.