EFFECT OF HARVESTING SEASON AND POSTHARVEST TREATMENTS ON STORAGE LIFE OF MEXICAN LIMES (Citrus aurantifolia Swingle)

Changes in susceptibility to chilling of citrus fruits vary with the low temperature applied, storage period, growing area, season, time of harvest and postharvest treatments. The objective of this study was to determine the effect of low temperatures on the quality of Mexican limes coated with wax applied through spraying or dipping, and treated with thiabendazole (TBZ) at 500 ppm and gibberellic acid (GA3) at 250 ppm. Weight loss, % of juice, degrees Brix, titratable acidity, color development and severity of chilling injury were examined weekly during storage. The results, obtained from fruit collected in two harvest periods, demonstrated that limes during the maximum production period of harvest in July, in contrast to those harvested in September, retained 90.6% of their fruit marketability. The conditions under which the best quality was obtained were the following: waxing by dipping + TBZ at 500 ppm + GA₃ at 250 ppm and 10C storage temperature with RH at 85–90%.     

FUZZY REASONING IN A MULTIAGENT SYSTEM OF SURVEILLANCE SENSORS TO MANAGE COOPERATIVELY THE SENSOR-TO-TASK ASSIGNMENT PROBLEM

In this work, a surveillance network composed of a set of sensors and a fusion center is designed as a multiagent system. Negotiation among sensors (agents) is proposed to solve the task-to-sensor assignment problem (the allocation of tasks to sensors), addressing several aspects. First, the fusion center determines the tasks (system tasks) to be performed by the network at each management cycle. To do that, a fuzzy reasoning system determines the priorities of these system tasks by means of a symbolic inference process using the fused data received from all sensors. In addition, a fuzzy reasoning process, similar to that performed in the fusion center, is proposed to evaluate the priority of local tasks (sensor tasks) now executed by each sensor. The network coordination procedure will be based on the system-task priorities, computed in the fusion center, and on the local priorities evaluated in each sensor. Priority values for system and sensor tasks will be the basis to guide a negotiation process among sensors in the multiagent system. The validity of the fuzzy reasoning approach is supported by the fact that it has been able to manage environmental situations in a similar way as experienced human operators do. Included results illustrate how the negotiation scheme, based on task priority and measured through their time-variant priority, allows the adaption of sensor operation to changing situations.     

Brief note: Differences in intracellular localization of corn stunt spiroplasmas in magnesium treated maize.

Maize plants infected with Spiroplasma kunkelii show symptoms similar to that of plants in a magnesium-deficient soil, and it has been shown that the spiroplasma alters the plants’ magnesium absorption. In the current study we compared changes associated to either spiroplasma infection, two soil magnesium levels and their combinations. Plant symptoms were recorded and correlated with transmission electron microscopy observations. Plants grown on a high magnesium treatment showed no macroscopical alterations nor organelle ultrastructural alterations, while plants on a low magnesium treatment showed macroscopical vein yellowing and, ultrastructurally, they had most chloroplasts and mitochondrial membranes altered. Infected plants on a low magnesium treatment had an ageing aspect, ultrastructurally showed chloroplasts and mitochondrial alterations similar to those non-infected and grown on a low magnesium treatment, and spiroplasma cells were found in phloem cells, but outside their cytoplasm. Infected plants on a high magnesium treatment showed similar symptoms and ultrastructural alterations as either non-infected plants on the low magnesium treatment or in infected plants on the low magnesium treatment, but differ from them in that the spiroplasma cells were located inside the cytoplasm. Results suggest that magnesium is involved in the plant-pathogen interaction.     

Comparative measurement of collagen bundle orientation by Fourier analysis and semiquantitative evaluation: reliability and agreement in Masson's trichrome,Picrosirius red and confocal microscopy techniques

Measurement of collagen bundle orientation in histopathological samples is a widely used and useful technique in many research and clinical scenarios. Fourier analysis is the preferred method for performing this measurement, but the most appropriate staining and microscopy technique remains unclear. Some authors advocate the use of Haematoxylin‐Eosin (H&E) and confocal microscopy, but there are no studies comparing this technique with other classical collagen stainings. In our study, 46 human skin samples were collected, processed for histological analysis and stained with Masson's trichrome, Picrosirius red and H&E. Five microphotographs of the reticular dermis were taken with a 200× magnification with light microscopy, polarized microscopy and confocal microscopy, respectively. Two independent observers measured collagen bundle orientation with semiautomated Fourier analysis with the Image‐Pro Plus 7.0 software and three independent observers performed a semiquantitative evaluation of the same parameter. The average orientation for each case was calculated with the values of the five pictures. We analyzed the interrater reliability, the consistency between Fourier analysis and average semiquantitative evaluation and the consistency between measurements in Masson's trichrome, Picrosirius red and H&E‐confocal. Statistical analysis for reliability and agreement was performed with the SPSS 22.0 software and consisted of intraclass correlation coefficient (ICC), Bland‐Altman plots and limits of agreement and coefficient of variation. Interrater reliability was almost perfect (ICC > 0.8) with all three histological and microscopy techniques and always superior in Fourier analysis than in average semiquantitative evaluation. Measurements were consistent between Fourier analysis by one observer and average semiquantitative evaluation by three observers, with an almost perfect agreement with Masson's trichrome and Picrosirius red techniques (ICC > 0.8) and a strong agreement with H&E‐confocal (0.7 < ICC < 0.8). Comparison of measurements between the three techniques for the same observer showed an almost perfect agreement (ICC > 0.8), better with Fourier analysis than with semiquantitative evaluation (single and average). These results in nonpathological skin samples were also confirmed in a preliminary analysis in eight scleroderma skin samples. Our results show that Masson's trichrome and Picrosirius red are consistent with H&E‐confocal for measuring collagen bundle orientation in histological samples and could thus be used indistinctly for this purpose. Fourier analysis is superior to average semiquantitative evaluation and should keep being used as the preferred method.     

Maribo cheese manufactured with concentrated milk: characteristics, maturation and yield

Research was carried out to study the feasibility of making maribo cheese using milk fortified by the addition of skim milk powder. A control (T-C) with 82 g l^-1 solids-non-fat (SNF) and 32 g l^-1 milk fat was included, along with three treatments with 11.7 (T-1), 14.6 (T-2) and 16.6 g l^-1 SNF (T-3) and standardization of the milk fat. Some chemical characteristics of the cheese milks and of the endproducts were studied and, in addition, cheese yield and the progress of maturation were monitored. It was observed that, as maturation proceeded in all treatments, there was a steady increase in the ripening index (soluble nitrogen/total nitrogen %), which indicates a progressive advance of proteolysis. Nevertheless, there were significant differences (p <.05) between the ripening indices of the control and the rest of the treatments. Furthermore, as the extent of maturation increased, α_sl-casein was degraded more than β-casein. The yield of cheese increased proportionally as the concentration of non-fat-solids in the milk increased.     

STUDIES ON THE UTILIZATION OF COCONUT MEAL A New Enzymic-Chemical Method for Fiber Free Protein Extraction of Defatted Coconut Flour

A simple enzymic-chemical protein extraction process was developed. Proteases rather than carbohydrases were more efficient for the enzymatic treatment. Dilute NaOH was more effective than dilute HCl for the complementary chemical treatment. The combined treatments were more efficient than each of the two separately. The method devised was equally effective when applied to live coconut meals obtained through different oil extraction techniques. The partial hydrolysis of the protein during the proteolytic enzyme treatment appears to enhance the protein extractability by the complementary chemical treatment. Further, the resultant product is free of fiber     

NUTRITIVE VALUE OF A FIBER-FREE COCONUT PROTEIN EXTRACT OBTAINED BY AN ENZYMIC-CHEMICAL METHOD

The fiber-free coconut extract obtained by an enzymic-chemical method (J. Food Sci. 38: 607) proved to have a higher protein nutritive value than that of the original coconut meal. The improvement is attributable in part to the fact that the fiber of unmodified coconut meal has an unfavorable effect on the nutritive value of coconut protein. Amino acid analysis revealed that the extracted protein had a higher total essential amino acid content including a higher lysine content and a higher lysineto-arginine ratio than the original coconut meal.