Optimization of electronic nose drift correction applied to tomato volatile profiling.

E-noses can be routinely used to evaluate the volatile profile of tomato samples once the sensor drift and standardization issues are adequately solved. Short-term drift can be corrected using a strategy based on a multiplicative drift correction procedure coupled with a PLS adaptation of the component correction. It must be performed specifically for each sequence, using all sequence signals data.

High throughput FT-MIR indirect analysis of sugars and acids in watermelon.

Indirect measurements of taste-related compounds are required when a high number of samples has to be analyzed in a short period of time, with a minimum cost. For this purpose, FT-MIR partial least square (PLS) regression models for the prediction of total soluble solids, sugars and organic acids have been developed using three sample sets including breeding lines and commercial varieties of watermelon. Specific models with excellent performance were obtained only for sugars.

FT-MIR determination of taste-related compounds in tomato: a high throughput phenotyping analysis for selection programs.

Background: Tomato taste is defined by the accumulation of sugars and organic acids. Individual analyses of these compounds using high-performance liquid chromatography (HPLC) or capillary zone electrophoresis (CZE) are expensive, time-consuming and are not feasible for large number of samples, justifying the interest of spectroscopic methods such as Fourier-transform mid-infrared (FT-MIR). This work analyzed the performance of FT-MIR models to determine the accumulation of sugars and acids, considering the efficiency of models obtained with different ranges of variation.

1-Methyltryptophan Modifies Apoplast Content in Tomato Plants Improving Resistance Against .

Plants can produce numerous natural products, many of which have been shown to confer protection against microbial attack. In this way, we identified 1-methyltryptophan (1-MT), a natural compound produced by tomato plants in response to attack, whose application by soil drench provided protection against this pathogen. In the present work, we have studied the mechanisms underlying this protection.

Influence of controlled deficit irrigation on tomato functional value.

The effect of controlled deficit irrigation (CDI) on the accumulation of carotenoids, polyphenols and l-ascorbic acid was studied in conventional and high lycopene tomato cultivars. Plants were initially irrigated to cover 100%ET and after the fruit set phase, the dose was reduced to 75% or 50% of ET. CDI had no significant effect on the accumulation of carotenoids, while it increased the levels of the hydroxycinnamic acids chlorogenic and ferulic acids, the flavonoid rutin and l-ascorbic acid.

Simultaneous determination of main phenolic acids and flavonoids in tomato by micellar electrokinetic capillary electrophoresis.

A methodology for the determination of tomato phenolic acids and flavonoids has been developed combining MEKC and DAD detection. The influence on polyphenol separation of pH and background electrolyte, BGE (borax, acetonitrile, methanol and SDS concentrations), was studied and optimized using response surface methodology and weighted desirability function. Separation of polyphenols was achieved within 20min at 15°C using 11.

Quantification of prominent volatile compounds responsible for muskmelon and watermelon aroma by purge and trap extraction followed by gas chromatography-mass spectrometry determination.

A dynamic headspace purge-and-trap (DHS-P&T) methodology for the determination and quantification of 61 volatile compounds responsible for muskmelon and watermelon aroma has been developed and validated. The methodology is based on the application of purge-and-trap extraction followed by gas chromatography coupled to (ion trap) mass spectrometry detection. For this purpose two different P&T sorbent cartridges have been evaluated.

Fast simultaneous determination of prominent polyphenols in vegetables and fruits by reversed phase liquid chromatography using a fused-core column.

A reversed-phase high-performance liquid chromatography method with photodiode array detection has been developed enabling the joint determination of 17 prominent flavonoids and phenolic acids in vegetables and fruits. A multi-segmented gradient program using a fused-core column for the separation of several phenolic classes (phenolic acids and flavonoids) has been optimised. The influence of extraction conditions (sample freeze-drying, ultrasound extraction, solvent composition and extraction time) has been also optimised using response surface methodology with tomato samples as a model.

High efficiency joint CZE determination of sugars and acids in vegetables and fruits.

In this work, an improved CE method for the medium-throughput determination of main organic acids (oxalate, malate, citrate), the amino acid glutamate and the sugars fructose, glucose and sucrose in several food matrices is described. These compounds have been identified as key components in the taste intensity of fruit and vegetable crops. Using a running buffer with 20 mM 2,6-pyridine dicarboxylic acid pH 12.

Evaluation of genotype and environment effects on taste and aroma flavor components of Spanish fresh tomato varieties.

Taste and aroma related compounds have been analyzed in a collection of four traditional varieties and two tomato hybrids, representing a wide variability in fruit shape and color, grown in different environments: screenhouse and open field. Protected cultivation tended to show lower sugar concentration (fructose and glucose) but similar acid contents (citric, malic, and glutamic acids). The decreased levels of sucrose equivalents and the similar ratios of sucrose equivalents to citric or glutamic acid contents indicated that protected cultivation, despite being useful to reduce the incidence of pests and viral diseases, reduces the organoleptic quality.

Modulation of organic acids and sugar content in tomato fruits by an abscisic acid-regulated transcription factor.

Growing evidence suggests that the phytohormone abscisic acid (ABA) plays a role in fruit development. ABA signaling components of developmental programs and responses to stress conditions include the group of basic leucine zipper transcriptional activators known as ABA-response element binding factors (AREBs/ABFs). AREB transcription factors mediate ABA-regulated gene expression involved in desiccation tolerance and are expressed mainly in seeds and in vegetative tissues under stress; however, they are also expressed in some fruits such as tomato.