[Show abstract][Hide abstract] ABSTRACT: We previously demonstrated the effectiveness of a hot water (HW) treatment (40°C for 7min) to reduce chilling injury (CI) in tomato fruit and described the global transcriptional changes associated with CI tolerance and susceptibility after 2 weeks of cold storage. In this study we describe the early transcriptional responses of HW treated and non-treated tomato fruit after a short-term cold storage (2 and 24h at 5°C). RNA-Seq analysis detected a large number of differentially expressed genes that varied from 575 (control fruit after 2h at 5°C) to 5100 (HW treated fruit after 24h at 5°C). The protective effect of HW treatment against chilling stress was related first with the up-regulation of AP2/EREBP and C2H2-type zinc finger transcription factors, which are known to induce the expression of cold-regulated genes, and second with the up-regulation of chaperonins and peptidyl-prolyl cis-trans isomerases, which prevent the denaturation and aggregation of proteins. Also, some genes related to pathogen resistance (TIR, NBS and LRR families) were up-regulated in HW treated fruit after chilling, suggesting a crosstalk between biotic and abiotic stress responses. Transcriptional changes that were induced in HW treated fruit at early stages of chilling and maintained after long-term cold storage included the up-regulation of genes related to heat stress and the down-regulation of genes related to cell wall degradation.
Full-text · Article · Jun 2015 · Postharvest Biology and Technology
[Show abstract][Hide abstract] ABSTRACT: Tomato fruit are horticultural products of great economic and nutritional value, whose transportation and marketing at low temperature are limited due to their susceptibility to develop chilling injury (CI). Hot water (HW) pre-treatments have been shown to reduce the CI symptoms in tomato fruit, but the molecular mechanisms involved in the acquisition of CI tolerance remain unclear. In the present work, a comparative transcriptomic analysis between HW treated and non-treated fruit before and after cold storage was carried out. RNA-Seq analysis detected a large number of differentially expressed genes that ranged from 2235 (heat shock) to 5433 (cold storage). Three clusters of genes were identified after 2 weeks of cold storage: the chilling-response included the down-regulation of genes involved in photosynthesis, metabolism of cell wall, lipid and ethylene, as well as the up-regulation of genes for trehalose synthesis and transcription factors (DOF and MYB); the chilling-susceptibility was associated with the down-regulation of genes involved in carotenoid biosynthesis, which correlates with the main CI symptom of uneven ripening; meanwhile, the chilling-tolerance was related to the up-regulation of genes for heat stress (heat shock proteins and heat shock transcription factors) and detoxification (glutathione S-transferases). The induced tolerance to CI in tomato fruit seems to be related first with the protection of cell wall and membranes integrity, and second with the restoration of ethylene biosynthesis and signaling.
Full-text · Article · Jan 2015 · Postharvest Biology and Technology
[Show abstract][Hide abstract] ABSTRACT: The variability in grain and starch characteristics and their relationship with the accumulation of starch granule associated proteins were investigated in five maize landraces of Northwest Mexico (Blando de Sonora, Chapalote, Elotero de Sinaloa, Reventador, and Tabloncillo). Significant differences were observed in grain hardness related traits, starch physicochemical properties, and structural properties. Blando de Sonora showed very soft grains, whereas the hardest grains were observed for Chapalote and Reventador. Starch granules isolated from landraces with hard grains contained more amylose and showed polygonal shapes, lower crystallinity and enthalpy of gelatinization, and greater retrogradation and proportion of long amylopectin chains. Proteomic analysis identified the enzymes granule-bound starch synthase I (GBSSI), starch synthase I and IIa, starch branching enzyme IIb, sucrose synthase 1, and pyruvate phosphate dikinase 2 as granule-associated proteins. The abundance of GBSSI correlated significantly with amylose content, consistent with the positive correlation observed between amylose and grain hardness. These results showed that the variability in the characteristics evaluated was mainly related to changes in the proportion of amylose in the starch granules, which were associated with differences in the expression of GBSSI. This information may be useful to define strategies for the exploitation and conservation of the landraces.
No preview · Article · Jan 2015 · Cereal Chemistry
[Show abstract][Hide abstract] ABSTRACT: The Mexican fruit fly, Anastrepha ludens Loew (Diptera: Tephritidae), is one of the most harmful pests of mango causing direct damage by oviposition on the fruit pulp. The mango for exportation is subjected to hydrothermal treatment as quarantine method for the control of this pest, but exposure to heat for long periods of time reduces considerably the quality and shelf-life of the fruit. The aim of this work was to study the morphological changes of third-instar larvae and adults of A. ludens after in vitro exposure at sublethal times. A heating block system was used to expose larvae at 46.1°C for 19.6 and 12.9 min, producing 94.6 and 70% mortality, respectively. Treated larvae were processed for optical microscopy. A fraction of surviving treated larvae was separated into containers on an artificial diet to allow development into adults. The sexual organs were dissected and processed for transmission electron microscopy analysis. Results showed that 94.6% of the treated larva population at 46.1°C for 19.6 min died and none of the surviving larvae eclosed to adults, as they developed as malformed puparia. For the in vitro treatment at 46.1ºC during 12.9 min, 70% of the treated larvae died and only 3.75% reached the adult stage, but ultrastructural damages in the male testes as well as in the female ovaries were observed. Additionally, 11.1% of the adult flies from the in vitro treatment also showed disfigurations in the wings and were incapable of flying. The analysis showed that surviving flies were unable to reproduce.
Full-text · Article · Jan 2015 · Journal of Insect Science
[Show abstract][Hide abstract] ABSTRACT: There is a growing interest for an environment-friendly nixtamalization process. Nixtamalization with calcium salts generates a minimum level of polluting residues. The effect of a nixtamalization process with calcium carbonate (NCC) on the indigestible carbohydrate content and starch digestibility of tortillas was evaluated. Traditional and NCC tortillas showed lower moisture content than commercial tortillas. Similar protein, ash, and carbohydrate content were found for the three tortillas, but NCC tortillas showed the highest lipid content. The NCC tortilla had the highest dietary fiber content, with the highest insoluble dietary fiber level. Fresh and stored (96 h) NCC and traditional tortillas showed similar resistant starch content. Fresh traditional tortilla showed the highest slowly digestible starch (SDS), but upon storage the rapidly digestible starch (RDS) content of NCC tortilla decreased. Fresh traditional and NCC tortillas had lower predicted glycemic index (pGI) than commercial tortillas, and upon storage, the three tortillas presented lower pGI values than their fresh counterparts. Consumption of tortillas produced with the NCC can produce positive effects in the human health.
No preview · Article · Sep 2014 · Journal of Cereal Science
[Show abstract][Hide abstract] ABSTRACT: Genetic analysis using quality protein maize (QPM) recombinant inbred lines derived from K0326Y QPM and W64Ao2 identified three quantitative trait loci (QTL) in bins 1.06, 7.02 and 9.03 associated with opaque2 endosperm modification. We evaluated the effects of these QTLs on protein accumulation and starch physicochemical properties. The QTL in bin 1.06 is close to α-zein genes, and vitreous individuals with this QTL had increased accumulation of 19-kDa α-zein, 27-kDa γ-zein and legumin-1. The QTL in bin 7.02 corresponds to the γ-zein locus, and greater accumulation of this protein was found in vitreous individuals. The QTL in bin 9.03 is close to starch biosynthetic genes; greater accumulation of granule-bound starch synthase and amylose was observed in vitreous kernel samples with this locus and that in bin 1.06, as well as less gelatinization enthalpy and crystallinity. Vitreous kernels contained angular-shaped/compact starch granules and more short-intermediate length chains of amylopectin. These results support that endosperm modification in QPM is associated with increased accumulation of γ-zein and other storage proteins, but also show that synthesis of less crystalline starch with more amorphous regions at the periphery of granules, which favor their packing and association with endosperm proteins, may also be an important factor.
[Show abstract][Hide abstract] ABSTRACT: Modeling thermal death kinetics and heat transfer can allow the prediction of temperature-time combinations for a thermal process, which will facilitate successful development of thermal treatments for pest control. The objectives of this study were: 1) to predict the number of surviving third-instar Anastrepha ludens after heating in a block system using a thermal death kinetic model, 2) to validate predictions of surviving larvae, determining survival of malformed puparia and, 3) to assess heat resistance by gender of eclosed adults. Exposure times for 44, 46, and 48 °C were calculated for 30, 50, 70, 90, and 99 % mortality. Predictions of surviving larvae were successfully validated; for all temperature-time combinations the difference was lower than one larva. Larvae that survived heat treatment and pupariated were scored as surviving larvae. Nevertheless, not all puparia eclosed to adults; some developed as malformed puparia. Adults from treated puparia that did not show malformations emerged at least 24 h later than adults from control puparia. Heat treatment also induced larviform, bottlenose and incompletely-eclosed puparia, but none of them eclosed as adult flies. From treated normal puparia, male larvae were more tolerant to heat in two of the eight temperature-time combinations where there was fly production. The thermal death kinetic model satisfactorily predicted the number of surviving third-instar A. ludens after heating in a block system at the studied sublethal temperature-time combinations.
[Show abstract][Hide abstract] ABSTRACT: In the state of Sinaloa México, traditional farmers still cultivate maize accessions with a wide diversity of morphological characteristics, but the gene reservoir maintained in these populations has been poorly studied and it is being lost due to changes in land use and the adoption of hybrid commercial varieties. The aim of this study was to evaluate the genetic diversity of some of these maize populations to contribute to their preservation. Twenty eight accessions were used for the analysis. DNA was extracted from 396 individuals and probed with 20 microsatellites distributed across the maize genome. A total of 121 alleles were obtained (average of 6.1 alleles per locus) and a total genetic diversity of 0.72. The UPGMA-cluster analysis, model-based population structure and principal component analysis revealed three major groups, one formed mainly by accessions of races typical of the Northwestern lowlands (Chapalote, Dulcillo del Noroeste, Tabloncillo Perla, Blando de Sonora and Elotero de Sinaloa) and the other two with accessions mainly from Tabloncillo and Tuxpeño. The high number of alleles per locus and total genetic diversity found in this study demonstrate a broad genetic basis of the accessions of maize landraces from Sinaloa, representing a gene reservoir useful in breeding programs.
[Show abstract][Hide abstract] ABSTRACT: The potential use of quality protein transgenic maize (genetically modified maize with the cDNA of amarantin) for preparation of flour and tortillas through an extrusion lime cooking process was investigated. Tortillas from extruded transgenic maize flour had similar physicochemical and sensory properties than those from the commercial brand MASECA™; however, the former had the highest (P < 0.05) protein content (12.91 vs 8.93%, db), essential amino acids content, calculated protein efficiency ratio (C-PER; 2.27 vs 0.90) and protein digestibility corrected amino acid score (PDCAAS; 55.54 vs 30.18%) and therefore they were nutritionally better. The use of transgenic maize for flour and tortilla preparation through an extrusion lime cooking process may have a positive impact on the nutritional status of people from countries where maize is the basic staple food. It also represents an alternative process to nixtamalization that requires little energy and water, it does not generate wastewater, and all components of the maize kernel are retained.
Full-text · Article · Nov 2013 · Journal of Cereal Science
[Show abstract][Hide abstract] ABSTRACT: Tomato apex necrosis virus (ToANV) is a new virus that causes important damage in tomato crops from the Culiacan Valley, Sinaloa, Mexico. To understand the relationship between ToANV and its vector Bermisia tabaci (Hemiptera: Aleyrodidae) (Gennadius) biotype B, laboratory and greenhouse trials were completed to: 1) determine the acquisition and inoculation access periods of ToANV by B. tabaci from tomato to tomato, 2) understand the transmission efficiency at different B. tabaci population densities, 3) estimate the time from inoculation of the virus at different B. tabaci densities to manifestation of symptoms in the plants, and 4) determine the retention time of the virus by the insect vector. The presence of the virus in plants was determined by reverse transcription-polymerase chain reaction amplification ofa 795-bp fragment (GenBank JN704068), which is phylogenetically related to ToANV (GenBank EF063242). The results showed that B. tabaci is an effective vector for ToANV with relatively long acquisition (12 h) and inoculation (9 h) access periods; a single adult is capable of transmitting and retaining the virus for up to 7d, suggesting a persistent mode of transmission. These results will help in the development of management strategies for controlling the vector and the disease.
No preview · Article · Aug 2013 · Journal of Economic Entomology
[Show abstract][Hide abstract] ABSTRACT: Mexico has the greatest diversity of Agave species in the world and considering their uses in traditional medicine, these plants could be a rich source of bioactive compounds. In this research, we studied five wild Agave species from Sinaloa, México (A. rzedowskiana, A. impressa, A. ornithobroma, A. schidigera and A. angustifolia) and one cultivated (A. tequilana). They were evaluated for antioxidant- and antibacterial activities and chemical composition. Statistical analysis consisted of a completely randomized design with one factor analysis of variance and the means were contrasted by the Tukey test (p ≤ 0.05). Agave tequilana showed the highest antibacterial activity with a Minimal Inhibitory Concentration (MIC) of 5 mg/mL, while A. rzedowskiana showed the highest antioxidant capacity by the DPPH method; both activities were higher than those reported for other Agave species. Agave ornithobroma had a higher content of the evaluated phytochemicals, mainly triterpenes and steroids. An activity based separation was carried out with the hexane extract of A. rzedowskiana; chromatographic separation and analysis by gas chromatography–mass spectrometry (GC–MS) showed 2-(3,4-dimethoxyphenil)-N-methylethanolamine, 9-octadecenoic acid and α-tocopherol (vitamin E) as the most abundant compounds. α-Tocopherol was clearly associated with the hexane extract antioxidant activity. This research showed a variety of phytochemicals in the studied Agave species and some of these species showed the highest antibacterial and antioxidant activities published up to date for this genus.
No preview · Article · Aug 2013 · Industrial Crops and Products
[Show abstract][Hide abstract] ABSTRACT: Introduction. Tomato fruit is susceptible to develop chilling injury (CI), a physiological disorder caused by low, non-freezing temperatures that impair its postharvest quality. Hot water (HW) treatments in tomato fruits have shown to induce CI tolerance , although the molecular mechanisms involved in that process remain unclear. The aim of the present work was to evaluate the effects of HW and cold storage over transcriptional changes in tomato fruits. Methods. Tomato (cv. Micro-Tom) fruits were harvested at mature green stage and immersed for 7 min in water at 40 °C (HW) or at 20 °C (C), followed by storage at 5 °C for 14 d to induce chilling stress, and then at 20 °C for 14 d to allow ripening and symptoms development . Total RNA was isolated from pericarp tissue using Trizol, and purified using RNeasy MinElute Cleanup Kit. Sequencing was performed on 5500 SOLiD System with the Exact Call Chemistry module. SOLiD raw reads were analyzed with the software CLC Genomic Workbench Version 5.5. Trimmed reads (quality >20, length >25 bp) were mapped in color-space against the tomato "ITAG2.3_cdna" reference using default parameters. Unique gene reads were normalized by the quantile method, and then were statistically analyzed (Kal's test) for differential expression. Genes with FDR <0.01, and fold change ±2 were considered as differentially expressed (DE). Results. A total of 23,375,457 reads (75 bp) were obtained from the six samples sequenced. After trimming by quality and length, 15,507,024 reads (66.3%) were retained. Of the trimmed sequences, 10,297,848 reads (66.4%) were uniquely mapped to the reference. Unique gene reads were subjected to quantile normalization to remove the bias of sequencing depth across all samples. Hierarchical clustering (Fig.1) showed that the expression profiles of tomato fruits are more affected by the storage time than by the treatment (C or HW). Interestingly, expression profiles at time zero (0h) are similar to those at ripening (14+14d), while the samples of chilling response (14d) are in a more distant group. Pair-wise comparisons against C-0h (Table 1) showed 1,753 DE genes immediately after heat shock (HW-0h), 3,245 and 3,312 DE genes were detected in the chilling response group (C-14d and HW-14d), meanwhile 2,099 and 1,985 DE genes were observed in the ripening group (C-14+14d and HW-14+14d). Conclusions. The transcriptional changes described here will be very useful in the identification of key genes associated with CI tolerance and susceptibility in tomato fruit.
[Show abstract][Hide abstract] ABSTRACT: El fruto de tomate es susceptible de desarrollar daño por frío (DF), un desorden fisiológico causado por temperaturas bajas que deterioran su calidad postcosecha. El objetivo del presente trabajo fue evaluar el efecto de un tratamiento hidrotérmico (THT) en la reducción del desarrollo de DF. Frutos de tomate fueron sumergidos durante 7 minutos en agua a 20 °C (control) o 40 °C (THT), antes de ser almacenados a 5 °C por 14 d, seguido de 20 ºC por 14 d. Durante el almacenamiento en frío, el THT redujo en 32% la fuga de electrolitos en pericarpio, indicando una mayor integridad de la membrana celular. Una vez retirados del frío y almacenados a 20 °C, los frutos con THT mostraron una menor (48%) velocidad de respiración respecto al control, lo que sugiere una menor demanda de energía metabólica para reparar el daño celular. Los principales síntomas visuales de DF fueron maduración irregular y marchitez, y la aplicación del THT logró una reducción del 40% en el Índice de DF respecto al control. Los frutos con THT alcanzaron un estado de madurez más avanzado, como se evidencia por los parámetros de color (mayor a* y ΔE, menor °Hue) y una menor firmeza del pericarpio. Por otra parte, los frutos con THT presentaron un menor % de pérdida de peso, lo cual fue reflejado en una menor marchitez. Estos resultados muestran que el THT logró reducir el desarrollo de DF, el cual pudo ser monitoreado mediante los parámetros físicos y fisiológicos antes mencionados.
[Show abstract][Hide abstract] ABSTRACT: Apple is the most popular template fruit consumed all over the world. However, the susceptibility of apples and their products to enzymatic browning and fruit softening during processing operations and storage reduces the overall quality and limits its shelf life and marketability. Actually, numerous research efforts pursue the development of new ways of preventing browning in fresh-cut fruits. In this sense, the combination of hot water treatment with dipping additives could be an effective alternative with great potential to be used commercially. Therefore, the aim of this study was to evaluate the effect of hot water treatment, N-acetylcysteine and calcium chloride dips on quality retention and enzymatic activity of fresh-cut Red Delicious apple. Whole fruits were dipped in water at ambient temperature (25°C, 10 min) (AWD) or subjected to hot water dipping treatment (HWD) at 45ºC for 10 min. After immersions, fruits were minimally processed and dipped for 3 min in N-acetylcysteine (NAC), calcium chloride (CaCl2) or their combination and stored at 4°C for 25 days. External colour changes, firmness, polyphenol oxidase (PPO) and peroxidase (POD) activities and sensory analysis were evaluated. The results obtained showed that HWD+NAC-CaCl2 treatment retained firmness, delayed colour changes and browning of fresh-cut apple during 25 days of storage compared with the other treatments. In addition, this combination effectively inhibited PPO and POD activities in the apple slices. Sensory results indicated that HWD+NAC-CaCl2 treatment did not adversely affect the attributes of fresh-cut apple, therefore can be considered a good alternative to improve the quality of fresh-cut Red Delicious apples.
Full-text · Article · Apr 2013 · Journal of Food Agriculture and Environment
[Show abstract][Hide abstract] ABSTRACT: Salmonellosis is an important zoonotic disease but little is known about the role that free-living animals play as carriers of this pathogen. Moreover, the primary route of infection in the wild needs to be elucidated. The aim of this study was to determine the source and the route of transmission of Salmonella enterica serovar Albany (S. Albany) infection in captive zoo wild animals in the Culiacán Zoo. A total of 267 samples were analyzed including 220 fecal samples from zoo animals, 15 fecal samples from rodents, 5 pooled samples each of two insects (Musca domestica and Periplaneta americana), and 22 samples of animal feed. We detected S. Albany in 28 (10.5%) of the samples analyzed, including in samples from raw chicken meat. Characterization of isolates was performed by serotyping and pulsed-field gel electrophoresis. All isolates shared a single pulsed-field gel electrophoresis profile, indicating a possible common origin. These data suggest that the infected meat consumed by the wild felines was the primary source of infection in this zoo. It is likely that the pathogen was shed in the feces and disseminated by insects and rats to other locations in the zoo.
Full-text · Article · Mar 2013 · Journal of Zoo and Wildlife Medicine
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to determine the best combination of extrusion process variables for the production of whole quality protein maize (EQPMF) and common bean (ECBF) flours to prepare a high antioxidant activity mixture (EQPMF + ECBF) suitable to produce a nutraceutical beverage with high acceptability elaborated with a traditional Mexican formulation. Processing conditions were obtained from a factorial combination of barrel temperature (BT = 120–170 °C) and screw speed (SS = 120–200 rpm). Response surface methodology was applied to obtain maximum values for antioxidant activity (A
A) of the flour mixture (EQPMF + ECBF) and acceptability (A) of the nutraceutical beverage. The best combinations of extrusion process variables for EQPMF and ECBF to prepare an optimized mixture (60%EQPMF + 40%ECBF) were BT = 98 °C/SS = 218 rpm and BT = 105 °C/SS = 83 rpm, respectively. The optimized mixture had A
A = 14,320 μmol Trolox equivalent (TE)/100 g sample dry weight (dw) and a calculated protein efficiency ratio (C-PER) of 2.17. A 200 ml portion of a beverage prepared with 25 g of the optimized flour mixture had A
A = 3,222 μmol TE, and A = 89 (level of satisfaction “I like it extremely”). This nutraceutical beverage could be used as an alternative to beverages with low nutritional/nutraceutical value, such as those prepared with water, simple sugars, artificial flavoring and colorants, which are widely offered in the market.
Full-text · Article · Nov 2012 · Plant Foods for Human Nutrition
[Show abstract][Hide abstract] ABSTRACT: Chickpeas are rich sources of highly nutritious protein and dietary fibre; the health benefits of consuming legumes such as antioxidant activity (AoxA) could be effective for the expansion of their food uses. The technological properties and antioxidant potential of five pigmented chickpea cultivars were evaluated. Protein content of the grains varied from 24.9 to 27.4 g/100 g sample (dw). The cooking time (CT) of the whole grains ranged from 90.5 to 218.5 min; the lowest CT corresponded to Black ICC3761 cultivar. The total phenolic content (TPC) and AoxA [oxygen radical absorbance capacity (ORAC) value] varied from 1.23 to 1.51 mg GAE/g sample (dw) and from 5011 to 5756 μmol TE/100 g sample (dw), respectively; Red ICC13124 showed the highest ORAC value. The differences in technological properties and AoxA among cultivars could be used in chickpea breeding programmes. Chickpea cultivars could contribute significantly to the management and/or prevention of degenerative diseases associated with free radical damage.
Full-text · Article · Jun 2012 · International Journal of Food Sciences and Nutrition