RESUMO
Pseudomonas syringae pv. actinidiae is the etiological agent of kiwifruit canker disease, causing severe economic losses in kiwifruit production areas around the world. Rapid diagnosis, understanding of bacterial virulence, and rate of infection in kiwifruit cultivars are important in applying effective measures of disease control. P. syringae pv. actinidiae load in kiwifruit is currently determined by a labor-intense colony counting method with no high-throughput and specific quantification method being validated. In this work, we used three alternative P. syringae pv. actinidiae quantification methods in two infected kiwifruit cultivars: start of growth time, quantitative PCR (qPCR), and droplet digital PCR (ddPCR). Method performance in each case was compared with the colony counting method. Methods were validated using calibration curves obtained with serial dilutions of P. syringae pv. actinidiae biovar 3 (Psa3) inoculum and standard growth curves obtained from kiwifruit samples infected with Psa3 inoculum. All three alternative methods showed high correlation (r > 0.85) with the colony counting method. qPCR and ddPCR were very specific, sensitive (5 × 102 CFU/cm2), highly correlated to each other (r = 0.955), and flexible, allowing for sample storage. The inclusion of a kiwifruit biomass marker increased the methods' accuracy. The qPCR method was efficient and allowed for high-throughput processing, and the ddPCR method showed highly accurate results but was more expensive and time consuming. While not ideal for high-throughput processing, ddPCR was useful in developing accurate standard curves for the qPCR method. The combination of the two methods is high-throughput, specific for Psa3 quantification, and useful for research studies (e.g., disease phenotyping and host-pathogen interactions).
Assuntos
Actinidia , Pseudomonas syringae , Frutas , Doenças das Plantas , Pseudomonas syringae/genética , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Kiwifruit (Actinidia spp.) is a recently domesticated fruit crop with several novel-coloured cultivars being developed. Achieving uniform fruit flesh pigmentation in red genotypes is challenging. To investigate the cause of colour variation between fruits, we focused on a red-fleshed Actinidia chinensis var. chinensis genotype. It was hypothesized that carbohydrate supply could be responsible for this variation. Early in fruit development, we imposed high or low (carbon starvation) carbohydrate supplies treatments; carbohydrate import or redistribution was controlled by applying a girdle at the shoot base. Carbon starvation affected fruit development as well as anthocyanin and carbohydrate metabolite concentrations, including the signalling molecule trehalose 6-phosphate. RNA-Seq analysis showed down-regulation of both gene-encoding enzymes in the anthocyanin and carbohydrate biosynthetic pathways. The catalytic trehalose 6-phosphate synthase gene TPS1.1a was down-regulated, whereas putative regulatory TPS7 and TPS11 were strongly up-regulated. Unexpectedly, under carbon starvation MYB10, the anthocyanin pathway regulatory activator was slightly up-regulated, whereas MYB27 was also up-regulated and acts as a repressor. To link these two metabolic pathways, we propose a model where trehalose 6-phosphate and the active repressor MYB27 are involved in sensing the carbon starvation status. This signals the plant to save resources and reduce the production of anthocyanin in fruits.
Assuntos
Actinidia/metabolismo , Antocianinas/metabolismo , Metabolismo dos Carboidratos , Frutas/metabolismo , Proteínas de Plantas/metabolismo , Fosfatos Açúcares/metabolismo , Fatores de Transcrição/metabolismo , Trealose/análogos & derivados , Actinidia/genética , Carbono/deficiência , Perfilação da Expressão Gênica , Genes de Plantas/genética , Filogenia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase em Tempo Real , Nicotiana/metabolismo , Fatores de Transcrição/genética , Trealose/metabolismoRESUMO
Plants alter their development in response to changes in their environment. This responsiveness has proven to be a successful evolutionary trait. Here, we tested the hypothesis that two key environmental factors, light and nutrition, are integrated within the axillary bud to promote or suppress the growth of the bud into a branch. Using petunia (Petunia hybrida) as a model for vegetative branching, we manipulated both light quality (as crowding and the red-to-far-red light ratio) and phosphate availability, such that the axillary bud at node 7 varied from deeply dormant to rapidly growing. In conjunction with the phenotypic characterization, we also monitored the state of the strigolactone (SL) pathway by quantifying SL-related gene transcripts. Mutants in the SL pathway inhibit but do not abolish the branching response to these environmental signals, and neither signal is dominant over the other, suggesting that the regulation of branching in response to the environment is complex. We have isolated three new putatively SL-related TCP (for Teosinte branched1, Cycloidia, and Proliferating cell factor) genes from petunia, and have identified that these TCP-type transcription factors may have roles in the SL signaling pathway both before and after the reception of the SL signal at the bud. We show that the abundance of the receptor transcript is regulated by light quality, such that axillary buds growing in added far-red light have greatly increased receptor transcript abundance. This suggests a mechanism whereby the impact of any SL signal reaching an axillary bud is modulated by the responsiveness of these cells to the signal.
Assuntos
Meio Ambiente , Morfogênese , Petunia/crescimento & desenvolvimento , Vias Biossintéticas/efeitos dos fármacos , Vias Biossintéticas/genética , Vias Biossintéticas/efeitos da radiação , DNA Complementar/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Genes de Plantas , Luz , Dados de Sequência Molecular , Morfogênese/efeitos dos fármacos , Morfogênese/efeitos da radiação , Petunia/efeitos dos fármacos , Petunia/genética , Petunia/efeitos da radiação , Fósforo/farmacologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/efeitos da radiação , Caules de Planta/efeitos dos fármacos , Caules de Planta/genética , Caules de Planta/efeitos da radiação , Análise de Componente Principal , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/efeitos da radiação , Fatores de Transcrição/metabolismoRESUMO
The origins of crop diseases are linked to domestication of plants. Most crops were domesticated centuries--even millennia--ago, thus limiting opportunity to understand the concomitant emergence of disease. Kiwifruit (Actinidia spp.) is an exception: domestication began in the 1930s with outbreaks of canker disease caused by P. syringae pv. actinidiae (Psa) first recorded in the 1980s. Based on SNP analyses of two circularized and 34 draft genomes, we show that Psa is comprised of distinct clades exhibiting negligible within-clade diversity, consistent with disease arising by independent samplings from a source population. Three clades correspond to their geographical source of isolation; a fourth, encompassing the Psa-V lineage responsible for the 2008 outbreak, is now globally distributed. Psa has an overall clonal population structure, however, genomes carry a marked signature of within-pathovar recombination. SNP analysis of Psa-V reveals hundreds of polymorphisms; however, most reside within PPHGI-1-like conjugative elements whose evolution is unlinked to the core genome. Removal of SNPs due to recombination yields an uninformative (star-like) phylogeny consistent with diversification of Psa-V from a single clone within the last ten years. Growth assays provide evidence of cultivar specificity, with rapid systemic movement of Psa-V in Actinidia chinensis. Genomic comparisons show a dynamic genome with evidence of positive selection on type III effectors and other candidate virulence genes. Each clade has highly varied complements of accessory genes encoding effectors and toxins with evidence of gain and loss via multiple genetic routes. Genes with orthologs in vascular pathogens were found exclusively within Psa-V. Our analyses capture a pathogen in the early stages of emergence from a predicted source population associated with wild Actinidia species. In addition to candidate genes as targets for resistance breeding programs, our findings highlight the importance of the source population as a reservoir of new disease.
Assuntos
Actinidia/microbiologia , Proteínas de Bactérias/genética , Genoma Bacteriano , Doenças das Plantas/microbiologia , Pseudomonas syringae/genética , Actinidia/crescimento & desenvolvimento , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Frutas/crescimento & desenvolvimento , Frutas/microbiologia , Ilhas Genômicas , Itália , Japão , Nova Zelândia , Filogenia , Doenças das Plantas/etiologia , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/microbiologia , Polimorfismo de Nucleotídeo Único , Pseudomonas syringae/crescimento & desenvolvimento , Pseudomonas syringae/isolamento & purificação , Pseudomonas syringae/patogenicidade , Recombinação Genética , República da Coreia , Especificidade da Espécie , VirulênciaRESUMO
Tomato, melon, grape, peach, and strawberry primarily accumulate soluble sugars during fruit development. In contrast, kiwifruit (Actinidia Lindl. spp.) and banana store a large amount of starch that is released as soluble sugars only after the fruit has reached maturity. By integrating metabolites measured by gas chromatography-mass spectrometry, enzyme activities measured by a robot-based platform, and transcript data sets during fruit development of Actinidia deliciosa genotypes contrasting in starch concentration and size, this study identified the metabolic changes occurring during kiwifruit development, including the metabolic hallmarks of starch accumulation and turnover. At cell division, a rise in glucose (Glc) concentration was associated with neutral invertase (NI) activity, and the decline of both Glc and NI activity defined the transition to the cell expansion and starch accumulation phase. The high transcript levels of ß-amylase 9 (BAM9) during cell division, prior to net starch accumulation, and the correlation between sucrose phosphate synthase (SPS) activity and sucrose suggest the occurrence of sucrose cycling and starch turnover. ADP-Glc pyrophosphorylase (AGPase) is identified as a key enzyme for starch accumulation in kiwifruit berries, as high-starch genotypes had 2- to 5-fold higher AGPase activity, which was maintained over a longer period of time and was also associated with enhanced and extended transcription of the AGPase large subunit 4 (APL4). The data also revealed that SPS and galactinol might affect kiwifruit starch accumulation, and suggest that phloem unloading into kiwifruit is symplastic. These results are relevant to the genetic improvement of quality traits such as sweetness and sugar/acid balance in a range of fruit species.
Assuntos
Actinidia/metabolismo , Frutas/crescimento & desenvolvimento , Amido/metabolismo , Actinidia/enzimologia , Actinidia/genética , Actinidia/crescimento & desenvolvimento , Frutas/enzimologia , Frutas/genética , Frutas/metabolismo , Genótipo , Glucose/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , beta-Frutofuranosidase/genética , beta-Frutofuranosidase/metabolismoRESUMO
In the elderly, immunosenescence and malnourishment can contribute to increased risk and severity of upper respiratory tract infections (URTI). Gold kiwifruit (Actinidia chinensis 'Hort16A') contains nutrients important for immune function and mitigation of symptoms of infection, including vitamins C and E, folate, polyphenols and carotenoids. The objective of the present study was to evaluate whether regular consumption of gold kiwifruit reduces symptoms of URTI in older people, and determine the effect it has on plasma antioxidants, and markers of oxidative stress, inflammation and immune function. A total of thirty-two community-dwelling people (≥65 years) participated in a randomised crossover study, consuming the equivalent of four kiwifruit or two bananas daily for 4 weeks, with treatments separated by a 4-week washout period. Participants completed the Wisconsin Upper Respiratory Symptom Survey-21 daily, and blood samples were collected at baseline and at the end of each treatment and washout period. Gold kiwifruit did not significantly reduce the overall incidence of URTI compared with banana, but significantly reduced the severity and duration of head congestion, and the duration of sore throat. Gold kiwifruit significantly increased plasma vitamin C, α-tocopherol and lutein/zeaxanthin concentrations, and erythrocyte folate concentrations, and significantly reduced plasma lipid peroxidation. No changes to innate immune function (natural killer cell activity, phagocytosis) or inflammation markers (high-sensitivity C-reactive protein, homocysteine) were detected. Consumption of gold kiwifruit enhanced the concentrations of several dietary plasma analytes, which may contribute to reduced duration and severity of selected URTI symptoms, offering a novel tool for reducing the burden of URTI in older individuals.
Assuntos
Actinidia , Envelhecimento/imunologia , Ácido Ascórbico/sangue , Frutas , Imunidade Inata , Infecções Respiratórias/sangue , Infecções Respiratórias/prevenção & controle , Idoso , Antioxidantes/análise , Biomarcadores/sangue , Estudos Cross-Over , Eritrócitos/metabolismo , Feminino , Ácido Fólico/sangue , Humanos , Incidência , Peroxidação de Lipídeos , Masculino , Nova Zelândia/epidemiologia , Estresse Oxidativo , Pigmentação , Projetos Piloto , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/fisiopatologia , Índice de Gravidade de DoençaRESUMO
BACKGROUND: Gastrointestinal enteroendocrine cells express chemosensory bitter taste receptors that may play an important role in regulating energy intake (EI) and gut function. OBJECTIVES: To determine the effect of a bitter hop extract (Humulus lupulus L.) on acute EI, appetite, and hormonal responses. METHODS: Nineteen healthy-weight men completed a randomized 3-treatment, double-blind, crossover study with a 1-wk washout between treatments. Treatments comprised either placebo or 500 mg of hop extract administered in delayed-release capsules (duodenal) at 11:00 h or quick-release capsules (gastric) at 11:30 h. Ad libitum EI was recorded at the lunch (12:00 h) and afternoon snack (14:00 h), with blood samples taken and subjective ratings of appetite, gastrointestinal (GI) discomfort, vitality, meal palatability, and mood assessed throughout the day. RESULTS: Total ad libitum EI was reduced following both the gastric (4473 kJ; 95% CI: 3811, 5134; P = 0.006) and duodenal (4439 kJ; 95% CI: 3777, 5102; P = 0.004) hop treatments compared with the placebo (5383 kJ; 95% CI: 4722, 6045). Gastric and duodenal treatments stimulated prelunch ghrelin secretion and postprandial cholecystokinin, glucagon-like peptide 1, and peptide YY responses compared with placebo. In contrast, postprandial insulin, glucose-dependent insulinotropic peptide, and pancreatic polypeptide responses were reduced in gastric and duodenal treatments without affecting glycemia. In addition, gastric and duodenal treatments produced small but significant increases in subjective measures of GI discomfort (e.g., nausea, bloating, abdominal discomfort) with mild to severe adverse GI symptoms reported in the gastric treatment only. However, no significant treatment effects were observed for any subjective measures of appetite or meal palatability. CONCLUSIONS: Both gastric and duodenal delivery of a hop extract modulates the release of hormones involved in appetite and glycemic regulation, providing a potential "bitter brake" on EI in healthy-weight men.
Assuntos
Humulus , Glicemia , Cápsulas/farmacologia , Estudos Cross-Over , Ingestão de Energia/fisiologia , Fármacos Gastrointestinais/farmacologia , Humanos , Insulina , Masculino , Peptídeo YY , Extratos Vegetais/farmacologiaRESUMO
BACKGROUND: Previous studies with commercial kiwifruit cultivars have demonstrated that the taste of fruit with higher dry matter content (DM) is more liked by consumers. A unique replicated trial of kiwifruit genotypes (10 high/low DM × small/large-fruited genotypes) has provided an opportunity to consider how the genetic propensity for a kiwifruit to accumulate DM affects fruit flavour and texture. In the present study, eating-ripe fruit from each of the genotypes were assessed using a trained sensory panel and the relationships between these sensory attributes and fresh weight, DM, flesh firmness and soluble solids content (SSC) were explored. RESULTS: The genotypes provided a diversity of flavour and texture attributes, each of which varied in perceived intensity of the sensory experience. High-DM genotypes had higher SSC and were perceived as sweeter than low-DM genotypes. Sweet taste was closely associated with the perception of the tropical flavour and high-DM genotypes were found to have more tropical notes. Fruit size was associated with fruit texture, and small fruit were characterised by a firmer and more fibrous core. Large high-DM fruit were perceived as juicier than those of all other genotypes. CONCLUSIONS: Genotypes were perceived differently from one another, and differences in fruit size and DM content were reflected in fruit sensorial properties. This study is unique in demonstrating interactions between fruit size, DM and sensory properties. These findings could be relevant not only to kiwifruit but to fruiting crop breeders in general, because of the demonstrated potential for effects of fruit size and DM content on sweetness, flavour and fruit texture.
Assuntos
Actinidia/genética , Análise de Alimentos , Frutas , Genótipo , Paladar , Actinidia/anatomia & histologia , Actinidia/química , Tecnologia de Alimentos , Frutas/anatomia & histologia , Frutas/química , Humanos , Percepção GustatóriaRESUMO
The ability to quantify the colour of fruit is extremely important for a number of applied fields including plant breeding, postharvest assessment, and consumer quality assessment. Fruit and other plant organs display highly complex colour patterning. This complexity makes it challenging to compare and contrast colours in an accurate and time efficient manner. Multiple methodologies exist that attempt to digitally quantify colour in complex images but these either require a priori knowledge to assign colours to a particular bin, or fit the colours present within segment of the colour space into a single colour value using a thresholding approach. A major drawback of these methodologies is that, through the process of averaging, they tend to synthetically generate values that may not exist within the context of the original image. As such, to date there are no published methodologies that assess colour patterning using a data driven approach. In this study we present a methodology to acquire and process digital images of biological samples that contain complex colour gradients. The CIE (Commission Internationale de l'Eclairage/International Commission on Illumination) ΔE2000 formula was used to determine the perceptually unique colours (PUC) within images of fruit containing complex colour gradients. This process, on average, resulted in a 98% reduction in colour values from the number of unique colours (UC) in the original image. This data driven procedure summarised the colour data values while maintaining a linear relationship with the normalised colour complexity contained in the total image. A weighted ΔE2000 distance metric was used to generate a distance matrix and facilitated clustering of summarised colour data. Clustering showed that our data driven methodology has the ability to group these complex images into their respective binomial families while maintaining the ability to detect subtle colour differences. This methodology was also able to differentiate closely related images. We provide a high quality set of complex biological images that span the visual spectrum that can be used in future colorimetric research to benchmark colourimetric method development.
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Consumer acceptance of fruit is determined by size, flavour and ripeness. In this study we investigated how altering the carbohydrate supply to Actinidia chinensis var. chinensis 'Zesy002' kiwifruit altered the balance between growth and accumulation of metabolites. Canes were phloem girdled and fruit thinned to a leaf-to-fruit ratio (L:F) of either 2 (Low carbohydrate) or 6 (High carbohydrate) at either 38 (Early) or 86 (Late) days after anthesis (DAA) and compared with ungirdled control canes with a L:F of 3. Fruit growth, metabolite accumulation, cytokinin concentrations and maturation were monitored and the sensory attributes of ripe fruit were assessed. The final weight of Early-High and Late-High carbohydrate fruit was 38% and 16% greater compared with control fruit. High carbohydrate fruit had increased starch, soluble sugar and cytokinin concentrations and fruit began to mature earlier and those with a Low carbohydrate had decreased concentrations and matured later compared with control fruit. Control fruit were described by consumers as more acidic and under-ripe compared with those from Early-High carbohydrate canes, but as sweeter than those from Low carbohydrate canes. This study showed that carbohydrate supply can have a major impact on the growth, sugar accumulation and maturity of 'Zesy002' fruit sinks.
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Intermittent fasting improves metabolic and cardiac health. However, increased hunger towards the end of the fasting period may affect compliance and limit its application. Our aim was to determine the effect of anorexigenic agent co-therapy on subjective ratings of appetite during the 16-24 h period of a day-long water-only intermittent fast. Thirty adult men were recruited and required to fast for 24 h from 18:00 h to 18:00 h on the same day of the week for three subsequent weeks. Treatments of either a placebo or one of two doses (high dose; HD: 250 mg or low dose; LD: 100 mg) of a bitter hops-based appetite suppressant (Amarasate®) were given twice per day at 16 and 20 h into the fast. From 18-24 h of the 24 h fast, both the HD and LD treatment groups exhibited a statistically significant (p < 0.05) > 10% reduction in hunger. Additionally, the expected lunchtime increase in hunger that was present in the placebo group (12:00 h) was absent in both the HD and LD groups. These data suggest that appetite suppressant co-therapy may be useful in reducing hunger during intermittent fasting, and show that bitter compounds may regulate appetite independently of meal timing.
Assuntos
Jejum , Humulus/química , Fome/efeitos dos fármacos , Extratos Vegetais/farmacologia , Água , Adulto , Estudos Cross-Over , Relação Dose-Resposta a Droga , Método Duplo-Cego , Humanos , Masculino , Pessoa de Meia-Idade , Nova Zelândia , Extratos Vegetais/química , Adulto JovemRESUMO
Pseudomonas syringae pv. actinidiae (Psa) and Pseudomonas syringae pv. actinidifoliorum (Pfm) are closely related pathovars infecting kiwifruit, but Psa is considered one of the most important global pathogens, whereas Pfm is not. In this study of Actinidia deliciosa 'Hayward' responses to the two pathovars, the objective was to test whether differences in plant defense responses mounted against the two pathovars correlated with the contrasting severity of the symptoms caused by them. Results showed that Psa infections were always more severe than Pfm infections, and were associated with highly localized, differential expression of phytohormones and putative defense gene transcripts in stem tissue closest to the inoculation site. Phytohormone concentrations of jasmonic acid (JA), jasmonate isoleucine (JA-Ile), salicylic acid (SA) and abscisic acid were always greater in stem tissue than in leaves, and leaf phytohormones were not affected by pathogen inoculation. Pfm inoculation induced a threefold increase in SA in stems relative to Psa inoculation, and a smaller 1.6-fold induction of JA. Transcript expression showed no effect of inoculation in leaves, but Pfm inoculation resulted in the greatest elevation of the SA marker genes, PR1 and glucan endo-1,3-beta-glucosidase (ß-1,3-glucosidase) (32- and 25-fold increases, respectively) in stem tissue surrounding the inoculation site. Pfm inoculation also produced a stronger response than Psa inoculation in localized stem tissue for the SA marker gene PR6, jasmonoyl-isoleucine-12-hydrolase (JIH1), which acts as a negative marker of the JA pathway, and APETALA2/Ethylene response factor 2 transcription factor (AP2 ERF2), which is involved in JA/SA crosstalk. WRKY40 transcription factor (a SA marker) was induced equally in stems by wounding (mock inoculation) and pathovar inoculation. Taken together, these results suggest that the host appears to mount a stronger, localized, SA-based defense response to Pfm than Psa.
RESUMO
Exogenous application of a cytokinin-like compound forchlorfenuron (CPPU) can promote fruit growth, although often at the expense of dry matter (DM), an important indicator of fruit quality. Actinidia chinensis var. deliciosa 'Hayward' fruit are very responsive to CPPU treatments, but the mechanism underlying the significant fruit weight increase and associated decrease in DM is unclear. In this study, we hypothesised that CPPU-enhanced growth increases fruit carbohydrate demand, but limited carbohydrate supply resulted in decreased fruit DM. During fruit development, CPPU effects on physical parameters, metabolites, osmotic pressure and transcriptional changes were assessed under conditions of both standard and a high carbohydrate supply. We showed that CPPU increased fruit fresh weight but the dramatic DM decrease was not carbohydrate limited. Enhanced glucose and fructose concentrations contributed to an increase in soluble carbohydrate osmotic pressure, which was correlated with increased water accumulation in CPPU-treated fruit and up-regulation of water channel aquaporin gene PIP2.4 at 49 days after anthesis. Transcipt analysis suggested that the molecular mechanism contributing to increased glucose and fructose concentrations was altered by carbohydrate supply. At standard carbohydrate supply, the early glucose increase in CPPU fruit was associated with reduced starch synthesis and increased starch degradation. When carbohydrate supply was high, the early glucose increase in CPPU fruit was associated with a general decrease in starch synthesis but up-regulation of vacuolar invertase and fructokinase genes. We conclude that CPPU affected fruit expansion by increasing the osmotically-driven water uptake and its effect was not carbohydrate supply-limited.
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[This corrects the article on p. 1366 in vol. 8, PMID: 28824694.].
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Fruit esters are regarded as key volatiles for fruit aroma. In this study, the effects of cold storage on volatile ester levels of 'Hort16A' (Actinidia chinensis Planch. var chinensis) kiwifruit were examined and the changes in aroma perception investigated. Cold storage (1.5°C) for two or four months of fruit matched for firmness and soluble solids concentration resulted in a significant reduction in aroma-related esters such as methyl/ethyl propanoate, methyl/ethyl butanoate and methyl/ethyl hexanoate. Levels of these esters, however, were restored by ethylene treatment (100ppm, 24h) before ripening. A sensory panel found that "tropical" and "fruit candy" aroma was stronger and "green" odour notes less intensively perceived in kiwifruit which were ethylene-treated after cold storage compared to untreated fruit. The key findings presented in this study may lead to further work on the ethylene pathway, and innovative storage and marketing solutions for current and novel fruit cultivars.
Assuntos
Actinidia/química , Actinidia/efeitos dos fármacos , Ésteres/metabolismo , Etilenos/farmacologia , Percepção Gustatória , Actinidia/metabolismo , Frutas/química , Frutas/efeitos dos fármacos , Frutas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Odorantes/análise , OlfatoRESUMO
This study examined the effect of a Boysenberry beverage (750 mg polyphenols), an apple fiber beverage (7.5 g dietary fiber), and a Boysenberry plus apple fiber beverage (750 mg polyphenols plus 7.5 g dietary fiber) on gut health. Twenty-five individuals completed the study. The study was a placebo-controlled crossover study, where every individual consumed 1 of the 4 treatments in turn. Each treatment phase was 4-week long and was followed by a 2-week washout period. The trial beverages were 350 g taken in 2 doses every day (ie, 175 mL taken twice daily). The hypothesis for the study was that the combination of polyphenols and fiber would have a greater benefit on gut health than the placebo product or the fiber or polyphenols on their own. There were no differences in fecal levels of total bacteria, Bacteroides-Prevotella-Porphyromonas group, Bifidobacteriumspecies, Clostridium perfringens, or Lactobacillus species among any of the treatment groups. Fecal short chain fatty acid concentrations did not vary among treatment groups, although prostaglandin E2 concentrations were higher after consumption of the Boysenberry juice beverage. No significant differences were found in quantitative measures of gut health between the Boysenberry juice beverage, the apple fiber beverage, the Boysenberry juice plus apple fiber beverage, and the placebo beverage.
Assuntos
Bebidas/análise , Fibras na Dieta/administração & dosagem , Ácidos Graxos Voláteis/análise , Fezes/microbiologia , Frutas/química , Polifenóis/administração & dosagem , Adulto , Bacteroides/isolamento & purificação , Bifidobacterium/isolamento & purificação , Índice de Massa Corporal , Peso Corporal , Clostridium perfringens/isolamento & purificação , Estudos Cross-Over , DNA Bacteriano/isolamento & purificação , Dinoprostona/análise , Fezes/química , Feminino , Humanos , Imunoglobulina A/análise , Lactobacillus/isolamento & purificação , Masculino , Malus/química , Pessoa de Meia-Idade , Cooperação do Paciente , Porphyromonas/isolamento & purificação , Prevotella/isolamento & purificaçãoRESUMO
In this study three different approaches were employed to identify key odorants in Sauvignon blanc wines. First, the concentrations of the odorants were compared to their respective aroma detection thresholds. The resulting odor activity values (OAV) were transformed into a normalized and weighted measure that allows the aroma profiles of different wines to be compared and the contribution of a single aroma in a complex mixture to be evaluated. Based on their OAV, 3-mercaptohexanol and 3-mercaptohexyl acetate were the two most important aroma compounds in many Marlborough Sauvignon blanc wines. Due to limitations with the OAV approach, the study was extended to include aroma extract dilution analysis (AEDA), which revealed that ß-damascenone, together with the varietal thiols, esters, and higher alcohols, are key odorants in Sauvignon blanc wines. The final approach undertaken was aroma reconstitution and omission tests using a deodorized wine base and the creation of a model Marlborough Sauvignon blanc. Single compounds and groups of compounds were omitted from the model to study their impact on the sensory properties of the model wine. Reconstitution and omission confirmed that varietal thiols, esters, terpenes, and ß-damascenone are all important contributors to Sauvignon blanc aroma. The methoxypyrazines showed an important but relatively low impact in all three of the approaches undertaken in this study.
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Técnicas de Química Analítica/métodos , Odorantes/análise , Vinho/análise , Adulto , Éteres/análise , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Hexanóis/análise , Humanos , Masculino , Pessoa de Meia-Idade , Norisoprenoides/análise , Olfato , Compostos de Sulfidrila/análiseRESUMO
The effects of the lipase inhibitor, tetrahydrolipstatin (THL), on neonate Epiphyas postvittana (Walker) (Lepidoptera, Tortricidae) larvae were investigated by feeding on control artificial diets (with and without 2% ethanol) and diets containing 2% ethanol and one of three concentrations of THL (0.011%, 0.037% and 0.11%). Small but significant reductions in growth rate, percent pupation and time to pupation were observed for larvae feeding on 2% ethanol control diet compared with standard control diet, but larger reductions in all parameters occurred with increasing THL concentration. Third instar larvae fed 0.011% THL in the diet had 40% of the midgut lipase activity in the relevant control larvae and showed up-regulation of gene expression of the gastric lipase-like family but not the pancreatic lipase-like family of midgut lipases.
Assuntos
Lactonas/farmacologia , Lipase/antagonistas & inibidores , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Animais , Dieta , Feminino , Trato Gastrointestinal/enzimologia , Expressão Gênica , Larva/efeitos dos fármacos , Larva/enzimologia , Larva/crescimento & desenvolvimento , Lipase/genética , Lipase/metabolismo , Masculino , Mariposas/enzimologia , Orlistate , RNA Mensageiro/metabolismoRESUMO
Red-fleshed fruit occur in a small number of distantly related taxa in different sections of the genus Actinidia (kiwifruit). We describe and identify the anthocyanin profile of fruit of several Actinidia species. Differences in the relative amounts of cyanidin- and delphinidin-based anthocyanins determine whether the fruit appear red or purple. Cyanidin derivatives have been found in all Actinidia species that contain anthocyanins, whereas delphinidin derivatives are limited to two taxa: A. melanandra and A. arguta var. purpurea . The fruit of these not only contain a wider range of anthocyanins, but they also have greater concentrations. Anthocyanins of most Actinidia species are usually conjugated with either xylosyl-galactose or galactose, whereas A. deliciosa anthocyanins are conjugated with glucose and galactose.
Assuntos
Actinidia/química , Antocianinas/química , Frutas/química , PigmentaçãoRESUMO
OBJECTIVE: Investigate the relationship between body mass index (BMI) and intake of sugars and fat in New Zealand adults and children. DESIGN: Secondary analyses of National Nutrition Survey (1997) and Children's Nutrition Survey (2002) data for the New Zealand population. BMI calculated from height and weight; fat, sugars and sucrose (used as a surrogate for added sugars) intakes estimated from 24-hour diet recall. Ethnic-specific analyses of children's data. Relationships (using linear regression) between BMI and sugars/sucrose intakes; per cent total energy from fat; mean total energy intake from sucrose. Subjects classified into diet-type groups by levels of intake of fat and sucrose; relative proportions of overweight/obese children in each group compared with that of normal weight subjects using design-adjusted chi2 tests. SETTING: New Zealand homes and schools. SUBJECTS: 4379 adults (15+ years); 3049 children (5-14 years). RESULTS: Sugars (but not sucrose) intake was significantly lower among obese compared to normal weight children. In adults and children, those with the lowest intake of sugars from foods were significantly more likely to be overweight/obese. Sucrose came predominantly from beverages; in children, 45% of this was from powdered drinks. Sucrose intake from sugary beverages was not related to BMI. Per cent total energy (%E) from sucrose was significantly inversely related to %E from fat among adults and children. Proportions of overweight/obese adults or children in each diet-type group did not differ from that of normal weight individuals. CONCLUSIONS: Current sugars or sucrose intake is not associated with body weight status in the New Zealand population.