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Copyright of Ciencia Ergo Sum is the property of Universidad Autonoma del Estado de Mexico and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This research explores how random events influence the respiration rate in Hass avocado beyond deterministic models in order to develop better strategies for extending its shelf life. Understanding these factors can enhance the accuracy of postharvest management strategies. The Autoregressive Integrated Moving Average (ARIMA) model with exogenous variables (ARIMAX) is an alternative stochastic probability model which is capable of modeling complex, externally influenced phenomena such as respiration. This study aimed to elucidate the effect of three exogenous variables, namely temperature, relative humidity, and ambient illumination, on the respiration rate of Hass avocado fruits. Data on the respiration rate and exogenous variables were obtained using sensors coupled to a data acquisition system in a prototype of continuous airflow. The Box–Jenkins methodology was employed to construct the ARIMA models. The temperature, relative humidity, ambient illumination, and respiration rate variables were adjusted to the ARIMA models (3,1,2), ARIMA (1,1,2), ARIMA (1,1,2), and ARIMA (1,1,3), respectively. The ARIMAX (1,1,3) models were obtained from the pre-whitened respiration rate series. The impact detected in the transfer functions indicates increases in the respiration rate of 0.34%, 1.52%, and 0.99% for each unit increase in the temperature, relative humidity, and ambient illumination variables, respectively. In this regard, ARIMAX modeling is reliable for explaining the physiological response of Hass avocado fruits due to external factors. In future research, it is intended to extrapolate this stochastic modeling procedure to measure the effect of dynamic loads on the respiratory metabolism of fruits during transportation, where there is a considerable loss in the quality of fresh products. [ABSTRACT FROM AUTHOR]

Copyright of Ensayos - Revista de Economía is the property of Ensayos Revista de Economia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In agronomic design of experiments, researchers frequently assume linear associations between explanatory and response variables, also they assume a gaussian distribution or transform it. Inherent variability of the experiment units is not considered. Besides, it is frequent to analyze the time as a factor of a factorial design when repeated measures are taken through time, missing the opportunity to analyze the plant growth. New statistical models present the opportunity to analyze the raw data without transforming, they also can consider the variability of the experiment units as random components and they can identify the relationship between explanatory and response variables as linear or nonlinear. In cut roses production, one of the main quality factors is stem length, but is not clear how temperature, relative humidity and light affect it. The aim of this research was to analyze new statistical models to better understanding the impact of environmental variables on stem length of two rose cultivars (Samurai and Blush) during two peak production periods. The models used were: generalized linear models (GLM), generalized linear mixed models (GLMM), generalized additive models (GAM), generalized additive mixed models (GAMM), vector generalized lineal models (VGLM) and repeated measures model. The results showed that GAM model with a gamma distribution and identity link function was the best model with minimum BIC value and minimum error variance. It identified a nonlinear effect of relative humidity and linear effects of heat and light. The best conditions to produce plants between 50 and 70 cm, were 650 to 830 heat units and 82.5 to 85% of relative humidity. GAMM identified the period of April to May with cultivar Blush as the best conditions to produced roses. Repeated measures analysis confirmed that plants initiated high (low), remained so through time. [ABSTRACT FROM AUTHOR]

Soursop (Annona muricata L.) is a commercially important tropical fruit, whether fresh or processed as a pasteurized or frozen pulp used to prepare juice, drinks, nectar, ice cream, popsicles, and desserts. Besides preserving quality, another preoccupation in the processing of fruit pulps is product safety. Several studies show the association between pulp processing and the development of various microorganisms; however, few have focused on the association between L. monocytogenes and the pulp of sour fruits. The objective was to evaluate the effect of moderate thermal treatments on the inactivation of L. monocytogenes and the physicochemical properties in soursop pulp in order to determine the best processing conditions that will allow to maintain quality as well as to achieve an adequate level of safety. Thermal inactivation kinetics were obtained for L. monocytogenes inoculated in soursop pulp at five levels of temperature (50, 52.5, 55, 57.5, and 60 ℃) and different exposure times (0–60 min). The survival curves did not suggest a log-linear relationship, and were, consequently, fitted to the modified Gompertz equation. The results indicated that the modified Gompertz equation provided an acceptable goodness of fit. Five-log10 cycles reductions of L. monocytogenes were achieved at 50 ℃/60 min, 52.5 ℃/16 min, 55 ℃/10 min, 57.5 ℃/5 min, and 60 ℃/1.25 min. These 5-log10 treatments applied to the soursop pulp indicated that the soursop pulp showed changes in the color parameters and a decrease in the content of total sugars, reducing sugars, ascorbic acid, total phenols, and pH. [ABSTRACT FROM AUTHOR]

The respiratory metabolism of fruits is affected by multiple internal (product) and external (environmental) factors that often interact with each other. Among the external factors that have the greatest influence on respiration are temperature, air composition, moisture content, and illumination. This paper aims to elucidate the influence of environmental factors on the respiration rate of peach fruits based on transfer models obtained by dynamic regression modelling (ARIMAX). The fitted ARIMA models met the criteria of parsimony and white noise in residuals. The estimated coefficients of each model were statistically significant under the Durbin-Watson (DW), Akaike (AIC) and Schwarz (SBC) criteria. Transfer functions revealed 0.15% and 1.9% increase, and 0.001% decrease in the respiration rate of the peach fruit for each unit of change in temperature, relative humidity, and the illumination of the storage environment, respectively. The respiration rate response took place 1-8 minutes after the change in environmental variables had occurred. It was concluded that the dynamic regression modelling is reliable for predicting the physiological response of fruits the effect of external factors imposed continuously during postharvest handling. [ABSTRACT FROM AUTHOR]

The squash nigrum spinosum is one of the main genotypes that are commercialized in Mexico, the United States of America and Canada, with the Latin and Asian communities being the main consumers. Generally, the works reported in this species are focused on the genus virens levis, but there is very little information on the post-harvest behavior of genotype n. spinosum under refrigerated storage. For this, fruits were harvested in horticultural maturity and stored at room temperature (20 ±2 °C) and at low temperature (10 ±1 °C, 85% RH) for three periods of time (3, 6 and 9 weeks) with and without the application of 1-methylcyclopropene (0, 500 and 1 000 nL L-1) to reduce viviparism. The variables evaluated were humidity percentage, titratable acidity, SST (°Brix), chlorophyll a and b content and total, content of total sugars (sucrose, fructose and glucose), weight loss and percentage of viviparism. The results showed an average moisture content of 94%, with low SST content (4.5-5.2%) that remains unchanged during storage, a fructose and glucose content of 1.07% and 0.89% respectively, without the presence of sucrose. The fruits maintained their appearance characteristics with refrigerated storage for 3 weeks, but at 6 and 9 weeks, the dehydration of thorns was evident, although both doses of 1-MCP (500 and 1000 nL L-1) significantly reduced the viviparism, increased the susceptibility to the incidence of fungi mainly Fusarium sp. [ABSTRACT FROM AUTHOR]