DSpace Angular :: Browsing by Author "Contreras, Carolina"

Browsing by Author "Contreras, Carolina"

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Cerros isla en las ciudades de Chile: oportunidades para una planificación ecológica
(Universidad de Chile. Instituto de la Vivienda, 2023) Picon Meleda, María Catalina; Contreras, Carolina; Berrizbeitia, Anita; Barrera, Francisco de la; Reyes-Paecke, Sonia; CEDEUS (Chile); Pontificia Universidad Católica de Chile. Escuela de Arquitectura
Island hills (IHs) represent elements of important natural and cultural heritage value. However, despite their notable presence in Latin American cities, there is little documented knowledge that may facilitate their recognition and incorporation into urban planning. The objective of this work is to identify, classify, and characterize the mostly non-urbanized IHs located within the urban area of the 16 regional capital cities of Chile. The 75 IHs identified were classified into three typologies and characterized according to their land coverage, buildings, and associated regulations. In the 16 cities, there are 32 urban island hills, 24 urban hills on the urban edge, and 19 hills that are part of mountain ridges on the urban edge, concentrated in Santiago, Concepción and Copiapó. These covers consisting of by native forest, shrublands, and forestry plantations in the southern part of the country, and soils with scarce vegetation in the northern area, reflecting the geographic diversity as well as the pressures and uses that exist in the territory. Thus, Concepción’s IHs have 30% or more of their surface covered by forestry plantations; and of the total, 83% of the IHs have built elements and 36% have heritage elements. In terms of urban regulations, there is no typical zoning for hills, and diverse uses coexist.
Identification, characterization, and expression of lipoxygenase genes in sweet cherry (Prunus avium L.) cv. Regina and their relationship with the development of an herbaceous off-flavor during fruit ripening
(2024) Villavicencio, Juan David; Tobar, Jose; Zoffoli, Juan Pablo; O'Brien, Jose Antonio; Contreras, Carolina
Flavor is an essential characteristic of fruit quality and is significant for consumers. Off-flavors have been reported in several fruits, including sweet cherry. This fruit has been reported to show an herbaceous/grassy-like flavor. The herbaceous off-flavor in sweet cherries detected in cultivar Regina has been related to the differential development of aroma compounds such as short-chain aldehydes and esters. One of the main biosynthesis pathways for these compounds is the fatty acid oxidation mediated by lipoxygenases (LOX). In order to have a better understanding of the biological basis of the differences in the volatile profile, the LOX gene expression profile was characterized during fruit development with and without herbaceous off-flavor. A genome-wide analysis of LOX in sweet cherry was carried out and compared to other species such as Arabidopsis, tomato, apple, prunus and strawberry. The structural features of 9-LOX and 13-LOX genes, encoded protein domains and their synteny were examined. Moreover, we analyzed the LOX expression at four developmental stages along ripening by RT-qPCR. Thirteen LOX gene candidates (six 9-LOX and seven 13-LOX) were identified. The 13-LOXs, PaLOX10, PaLOX11, and PaLOX12 were differentially expressed in herbaceous sweet cherries. Furthermore, their expression profile positively correlated with key volatile compounds linked to the herbaceous off-flavor. Overall, this study involves the genome-wide characterization of the LOX family in Prunus avium cv. Regina and provides information that can aid in studying LOX-related fruit deterioration in sweet cherries and associated species.
Influence of preharvest environmental conditions and postharvest relative humidity on the appearance of orange peel disorder in sweet cherry during fruit development and storage
(2024) Coye, Francisca; Calderon-Orellana, Arturo; Zoffoli, Juan P.; Contreras, Carolina
Orange peel, a physiological disorder, has been reported in Chilean sweet cherries ( Prunus avium (L.) L.) after 35-45 d under modified atmosphere packaging (MAP). The ontogeny of the disorder is unknown, and preharvest factors have not been thoroughly investigated. This study involved two experiments to elucidate the association between environmental factors and the incidence of the orange peel disorder. In the first experiment, plant water potential, fruit position on the tree, relative humidity (RH), and radiation of sweet cherry trees were studied in 'Regina', 'Kordia', and 'Lapins'. The second experiment focused on the interaction effect of heat during fruit development and the RH during storage in 'Lapins'. The first experiment showed no clear response of orange peel incidence to natural variations in air temperature, vapor pressure deficit, and transmitted solar radiation (PPFD) within trees. However, significant differences in the incidence, severity, and timing of the disorder detection were observed among cultivars. In 'Lapins', orange peel disorder began before harvest in the green stage, 33.7 %, while 'Regina' and 'Kordia' showed negligible incidences of 1.25% and 0%, respectively. At postharvest, no differences were found among tree sections, either in incidence or severity of the disorder. For the second experiment, no differences in incidence were found in heated fruit during preharvest or postharvest RH treatments. However, it was observed that the higher the RH (100%), the lower the severity index (3.6) was for the orange peel disorder. The high incidence of the disorder during postharvest under natural or induced environmental conditions in the three cultivars evaluated demonstrates that RH mainly affects the orange peel disorder.
Leptin levels, seasonality and thermal acclimation in the Microbiotherid marsupial Dromiciops gliroides: Does photoperiod play a role?
(2017) Franco, Marcela; Contreras, Carolina; Place, Ned J.; Bozinovic Kuscevic, Francisco; Nespolo Rossi, Roberto
NIR spectral models for early detection of bitter pit in asymptomatic 'Fuji' apples
(2021) Rene Mogollon, Miguel; Contreras, Carolina; de Freitas, Sergio Tonetto; Zoffoli, Juan Pablo
Bitter pit (BP) is a physiological disorder that develops in apples, mainly during storage. This study sought to develop NIR spectral models for prediction of future BP incidence and severity in 'Fuji' apples using spectral data collected at harvest and during storage. Partial Least Square classification models obtained from spectra reflectance between 950 and 1200 nm were compared, starting at harvest, at 10 days postharvest and every 20 days thereafter over 110 days at 0 degrees C in relation to BP severity (number of pits per fruit) after 150 days at 0 degrees C. The models used data from a total of 3000 fruit, collected over two seasons (2018 and 2019) from two orchards. All models were evaluated for Accuracy, Sensitivity, Specificity, Positive Predicted Value (PPV) and Negative Predicted Value (NPV). In the validation dataset, Accuracy, Specificity and NPV values varied between 60 and 80 % and were independent of the time of evaluation during storage. Sensitivity and PPV values did not exceed 60 % in the same dataset. Here, BP incidences in fruit with severities of <8 pits per fruit, achieved accuracies and NPVs between 60 and 70 % in the calibration and validation datasets using spectral data collected at harvest. For comparison, the detection of high BP severities (8-9 pits per fruit), these same metrics achieved between 80 and 90 % using spectral data collected during the first 10 days of storage.
Oxidative status and metabolic profile in a long-lived bird preparing for extreme endurance migration
(2019) Gutierrez, Jorge S.; Sabat, Pablo; Castaneda, Luis E.; Contreras, Carolina; Navarrete, Lucas; Pena-Villalobos, Isaac; Navedo, Juan G.
The high metabolic activity associated with endurance flights and intense fuelling of migrant birds may produce large quantities of reactive oxygen species, which cause oxidative damage.Yet it remains unknown how long-lived birds prepare for oxidative challenges prior to extreme flights. We combined blood measurements of oxidative status and enzyme and fat metabolism in Hudsonian godwits (Limosa haemastica, a long-lived shorebird) before they embarked on non-stop flights longer than 10,000 km during their northbound migrations. We found that godwits increased total antioxidant capacity (TAC) and reduced oxidative damage (TBARS) as the pre-migratory season progressed, despite higher basal metabolic rates before departure. Elevations in plasma beta-hydroxybutyrate and uric acid suggest that lipid and protein breakdown supports energetic requirements prior to migration. Significant associations between blood mitochondrial cytochrome-c oxidase and plasma TAC (negative) and TBARS (positive) during winter indicate that greater enzyme activity can result in greater oxidative damage and antioxidant responses. However enzyme activity remained unchanged between winter and premigratory stages, so birds may be unable to adjust metabolic enzyme activity in anticipation of future demands. These results indicate that godwits enhance their oxidative status during migratory preparation, which might represent an adaptation to diminish the physiological costs of long-distance migration.
Países Bajos, territorio reversible
(2009) Contreras, Carolina
The Low Countries' experience with control of land and water is extensive. Its inhabitants possess comprehensive knowledge of its characteristics, dynamically interacting with their habitat. However, environmental and economic needs have required the review and even the reversal of this complex hydraulic system.
Postharvest physiology and storage potential of new Chilean raspberry cultivars
(2021) Contreras, Carolina; Hermosilla, Adolfo; Naranjo, Paulina; Pablo Zoffoli, Juan; Gambardella, Marina
Raspberries (Rubus ideaus L.) are highly perishable and susceptible to rot during storage. An exploratory study of postharvest physiology associated with maturity was carried out for three new Chilean raspberry cultivars: Santa Catalina, Santa Clara and Santa Teresa. Fruit of these cultivars were harvested at three maturity stages based on color: pink (C3), bright red (commercial maturity) (C4) and dark red (C5). Two experiments were carried out to: i) determine postharvest quality and physiological parameters associated with maturity stages in comparison to those fruits of the main cv. Heritage, and ii) evaluate storage potential at 0 and 4 degrees C of 'Santa Catalina'. In the first study, fruit quality parameters (such as weight, firmness, color, among others) of all the 'Santa' cultivars were assessed immediately after harvest, and the ethylene production and respiration rates (CO2) were recorded for 4 d at 20 degrees C. In the second experiment, 'Santa Catalina' was stored at 0 and 4 degrees C. According to the results of the first experiment, 'Santa Teresa' presented the largest fruit (7.9 g), followed by 'Santa Clara' (5.3 g), 'Santa Catalina' (4.9 g) and 'Heritage' (3.3 g). 'Santa Clara' (similar to 6 ng kg(-1) s(-1)) fruits had the highest levels of ethylene production, followed by 'Santa Catalina', and 'Santa Teresa' with the lowest production. Regardless the cultivar, the fruit at the C5 stage always showed the highest ethylene production. Overall, compared with 'Heritage', these three new cultivars presented better fruit quality at harvest. The 0 degrees C was an adequate storage temperature for 'Santa Catalina' reaching storage potential of 20 d without soft fruits; therefore, it is recommended for fresh markets.
Prestorage Temperature and Ultra-low Oxygen Treatments Affect Incidence of Physiological Disorders in Organic 'Granny Smith' Apples
(2018) Zoffoli, Juan Pablo; Sanguedolce, Valentina; Naranjo Gatica, María Paulina; Contreras, Carolina
Study of physiological and quality parameters during development and ripening of pepino (Solanum muricatum Aiton) fruit
(2019) Contreras, Carolina; Schwab, Wilfried; Mayershofer, Mechthild; Morales, Ignacio; Gonzalez-Agueero, Mauricio; Defilippi, Bruno G.
Pepino (Solanum muricatum Aiton) fruit served as an important crop in Pre-Columbian Andean cultures. Despite the fact that pepino has been known for centuries, information about maturity indices and physiological quality parameters of its fruit is scarce. The objective was to increase our knowledge of pepino fruit physiology and maturity to improve fruit handling and storage. Pepin fruit were studied during 2015 and 2016 seasons. During 2015, developmental and maturity studies were carried out, whereas in 2016 the developmental study was repeated. Twenty-five fruit were analyzed during six developmental stages ranging from immature (stage 1) to senescent fruit (stage 6). Fruit were analyzed for soluble solid content (SSC), titratable acidity (TA), color, respiration and ethylene production, soluble sugars, organic acids, and aroma. For the maturity assay, nonsignificant differences were found between green background color (M1) and white background color (M2) in the different quality parameters, with the exception of firmness. Pepin is a non-climacteric fruit with a low ethylene production rate. Unlike foreign cultivars, Chilean pepinos have low amounts of citric acid, being the predominant acids: malic and quinic. Out of 22 volatile compounds identified in this study, the predominant aroma volatiles are 3-methyl-3-butenyl acetate and 3-methyl-2-butenyl acetate from the terpenoid pathway, and trans-2-hexenal from the lipoxygenase pathway. The quality parameters changing in a ripening-dependent manner were firmness, SSC, aroma and color. Other parameters such as TA and organic acids stayed constant throughout development. In addition to color and SSC, this study also suggests aroma as a harvest index.
Ultra-Low Oxygen and Preconditioning Storage Regulate Ethylene Synthesis to Prevent Corky Disorders in 'Fuji' Apple
(2022) Riano, Camila; Ribba, Tomas; Marchant, Juan I.; O'Brien, Jose A.; Contreras, Carolina; Zoffoli, Juan P.
Corky disorders in apples represent a significant problem for long-term storage where controlled atmosphere (CA) is mainly used. Ultra-low oxygen (ULO) is an alternative to CA, which consists of low partial pressure of O-2 to maintain a low metabolism in the apple fruit, achieving an effective decrease in the ethylene production and physiological disorders. The aim of this research was to study the effectiveness of a short hypoxia period on the development of cork physiological disorders during the storage of apple. 'Fuji' apples were prestored under ULO (0.5 kPa O-2) for two periods of time (15 and 30 days) and at two temperatures (0 or 5 degrees C). Corky physiological disorders increased at 5 degrees C prestorage temperature; however, ULO treatments for 15 or 30 days at 0 or 5 degrees C achieved a significant reduction in corky disorders near to 1%, compared with control treatments. In addition, a considerable reduction in ethylene production for up to 30 days was observed in ULO-treated fruit at 0 and 5 degrees C. ULO for 30 days at 0 and 5 degrees C increased the internal production of ethanol and acetaldehyde, causing a lower sensory quality due to the presence of fermentative flavors in fruit stored at 5 degrees C. ULO of 15 days of conditioning decreased the relative expression of ethylene biosynthesis genes MdACS1 and MdACO1, resulting in lower ethylene production.

Browsing by Author "Contreras, Carolina"

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