Publications by authors named "Joana Pico"

Article Synopsis
  • Monoterpenoid biosynthesis in grape berries is linked to the accumulation of hexoses during ripening and is influenced by environmental factors like sunlight.
  • A study was conducted with 'Riesling' vines using girdling to limit nutrient flow and light-exclusion bags to reduce sunlight, revealing that girdling decreased photosynthesis and certain compound levels, while light exclusion reduced monoterpenoid levels.
  • Ultimately, while light exposure was crucial for the production of free monoterpenoids, girdling did not affect their total concentration, indicating that monoterpenoid synthesis is more influenced by light than by grape maturity or sugar levels.
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Legume proteins can be induced to form amyloid-like fibrils upon heating at low pH, with the exact conditions greatly impacting the fibril characteristics. The protein extraction method may also impact the resulting fibrils, although this effect has not been carefully examined. Here, the fibrillization of lentil protein prepared using various extraction methods and the corresponding fibril morphology were characterized.

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N-Hydroxypipecolic acid (NHP) is a signaling molecule crucial for systemic acquired resistance (SAR), a systemic immune response in plants that provides long-lasting and broad-spectrum protection against secondary pathogen infections. To identify negative regulators of NHP biosynthesis, we performed a forward genetic screen to search for mutants with elevated expression of the NHP biosynthesis gene FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1). Analysis of two constitutive expression of FMO1 (cef) and one induced expression of FMO1 (ief) mutants revealed that the AIPP3-PHD2-CPL2 protein complex, which is involved in the recognition of the histone modification H3K27me3 and transcriptional repression, contributes to the negative regulation of FMO1 expression and NHP biosynthesis.

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Pulsed light (PL) is a novel, non-thermal technology being used to control the microbial spoilage of foods and beverages. Adverse sensory changes, commonly characterized as "lightstruck", can occur in beers when exposed to the UV portion of PL due to the formation of 3-methylbut-2-ene-1-thiol (3-MBT) upon the photodegradation of iso-α-acids. This study is the first to investigate the effect of different portions of the PL spectrum on UV-sensitive beers (light-colored blonde ale and dark-colored centennial red ale) using clear and bronze-tinted UV filters.

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Bound volatiles are odorless aroma reservoirs that modify flavor when released during food processing, and their determination is important to understand the aroma of fruit beverages. However, the generation of oxidation/degradation artifacts during analyses of glycosidically-bound volatiles has not been compared across fruit species and their dependence on diverse acidic and enzymatic hydrolytic conditions remains unclear. This work aimed to optimize and compare different hydrolytic conditions for the analysis of glycosidically-bound volatiles in blueberries, raspberries, and grapes with a solid-phase microextraction - gas chromatography/mass spectrometry (SPME-GC/MS) methodology.

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Terpenes play a formative role in grape and wine flavor, particularly for high-terpenic cultivars. Differences in terpene profiles influence grape varietal character and vintage quality. Little is known about the endogenous factors controlling terpene biosynthesis in grape.

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Lignin, the second most abundant biopolymer, is a promising renewable energy source and chemical feedstock. A key element of lignin biosynthesis is unknown: how do lignin precursors (monolignols) get from inside the cell out to the cell wall where they are polymerized? Modeling indicates that monolignols can passively diffuse through lipid bilayers, but this has not been tested experimentally. We demonstrate significant monolignol diffusion occurs when laccases, which consume monolignols, are present on one side of the membrane.

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The consumption of small fruits has increased in recent years. Besides their appealing flavor, the commercial success of small fruits has been partially attributed to their high contents of phenolic compounds with multiple health benefits. The phenolic profiles and contents in small fruits vary based on the genetic background, climate, growing conditions, and post-harvest handling techniques.

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Blueberry aroma is one of the most important quality traits that influences consumer purchasing decisions. This study aimed to optimize and validate a solid-phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS) method for the quantification of 73 volatile compounds in northern highbush blueberries. A SPME extraction of blueberries with water and specific proportions of sodium chloride, citric acid, and ascorbic acid, for 60 min at 50 °C using a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber was optimal.

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Article Synopsis
  • Different methods have been used to measure α-Galacto-oligosaccharides (GOS) in beans, but results can vary greatly—up to 8 times—indicating a need for validated techniques.
  • This study optimized and validated a procedure for extracting the primary GOS types (raffinose, stachyose, verbascose) and compared two analytical methods: HPAEC/PAD and GC/MS.
  • GC/MS proved to be the more reliable method for quantifying GOS, with strong extraction efficiency and consistent results across various bean types, showing stachyose as the dominant GOS present.
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Wine fermentation processes are driven by complex microbial systems, which comprise eukaryotic and prokaryotic microorganisms that participate in several biochemical interactions with the must and wine chemicals and modulate the organoleptic properties of wine. Among these, yeasts play a fundamental role, since they carry out the alcoholic fermentation (AF), converting sugars to ethanol and CO together with a wide range of volatile organic compounds. The contribution of , the reference organism associated with AF, has been extensively studied.

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Article Synopsis
  • Folin-Ciocalteu and Fast Blue BB (FBBB) methods are used to measure total phenolics in food, but Folin-Ciocalteu often faces interference issues.
  • FBBB shows good performance with fruits and cereals, while its effectiveness in legumes hasn't been tested yet.
  • In a study of 24 flour samples, Folin-Ciocalteu had interferences in 75% of cases, while FBBB had some interference only in legumes and nuts; notably, FBBB with Solid Phase Extraction (SPE) was more sensitive.
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Losses of volatile compounds during baking are expected due to their evaporation at the high temperatures of the oven, which can lead to a decrease in the aroma intensity of the final product, which is crucial for gluten-free breads that are known for their weak aroma. Volatiles from fermentation and lipids oxidation are transferred from crumb to crust, and they flow out to the air together with Maillard and caramelisation compounds from the crust. In this study, the release to the oven of volatile compounds from five gluten-free breads (quinoa, teff and rice flours, and corn and wheat starches) and wheat bread during baking and toasting was measured in real-time using proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS).

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While it is known that salivary amylase changes perceived thickness in starch-based foods, the dynamics of oral breakdown of starch has not been related to that of sensory perception. This work examines the associations between in-mouth oral breakdown of starch by α-amylase and thickness of a semisolid product measured instrumentally and using a sensory panel. Pureed carrots made with added waxy maize (w/w) (0% (control), 0.

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The outstanding amount of phenolics and pectins of okra seeds and seedless pods, respectively, is well-known. However, their impact on bread nutritional quality, and particularly on slowing down α-amylase activity during crumb digestion, has never been studied. In this work, the phenolic and carbohydrate fractions of developed fine and coarse flours from okra seeds (OS) and seedless pods (OP) were investigated as well as their impact on wheat bread physical and nutritional quality.

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Background: Glucose transport across the intestinal brush border membrane plays a key role in metabolic regulation. Depending on the luminal glucose concentration, glucose is mainly transported by the sodium- dependent glucose transporter (SGLT1) and the facilitated-transporter glucose transporter (GLUT2). SGLT1 is apical membrane-constitutive and it is active at a low luminal glucose concentration, while at concentrations higher than 50 mM, glucose is mainly transported by GLUT2 (recruited from the basolateral membrane).

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Some fruit phenolics are reported to attenuate intestinal glucose transport through inhibitory action at the luminal brush border membrane. This effect may contribute, in part, to the ability of flavonoid-rich food to regulate glucose homeostasis of meals rich in available carbohydrates. For the first time, the potential of green banana flours to inhibit transepithelial glucose transport was investigated in the context of a model starchy meal (wheat cake) using a simulated digestion/Caco-2 human intestinal cell model.

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Use of banana flours as functional ingredients is growing due to their nutritional benefits derived from phenolics and dietary fiber. However, the effect oven-drying, freeze-drying and extrusion on the phenolic compounds or starch digestibility is not understood. In this work, phenolic acids (gallic acid, caffeic acid), flavan-3-ols (epicatechin, catechin) and flavonols (quercetin-3-O-glucoside and myricetin) were quantified in banana flour processed by different methods.

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The analysis of bread aroma is essential in order to evaluate its quality as well as to improve it. The use of different methodologies for the analysis of volatile compounds lead to varying results. In the present study, the matrix effect, extraction efficiency, limits of detection and quantification as well as the precision of a proposed solvent-assisted flavour evaporation methodology were evaluated for the first time and compared with a reference method, both differing in the distillation step.

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Gluten-free bakery products usually exhibit weak aroma. Their main constituents are flours and starches, which contain aroma precursors but can also contribute additional volatiles in low concentrations. Static headspace (SHS), solid-phase microextraction (SPME) and solvent-assisted flavour evaporation (SAFE) coupled to GC/QTOF were compared for their efficacy in the analysis of volatiles in corn starch.

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Fried battered foods are widely consumed worldwide. In this study, the influence of the replacement of native wheat flour by extruded flours (7.5 and 15%) subjected to different extrusion severities on chicken nuggets was assessed.

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The aroma of bread crust, as one of the first characteristics perceived, is essential for bread acceptance. However, gluten-free bread crusts exhibit weak aroma. A SPME-GC/QTOF methodology was optimised with PCA and RSM and validated for the quantification of 44 volatile compounds in bread crust, extracting 0.

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The aim of this research was to study the effect of different gluten-free flours (yellow and white corn, rice, oat, teff, buckwheat, amaranth and quinoa) and starches (wheat, corn and potato) on the generation of volatile compounds in the fermented doughs and crumbs. Volatile compounds were analyzed by static headspace-gas chromatography/mass spectrometry (SHS-GC/MS). Nine fermentation and lipid oxidation volatile compounds were evaluated, which were found to be the same from dough to crumb but vary in levels.

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The freezing of wheat bread before aroma analyses is a common practice in order to preserve loss of the volatile profile. However, the impact of the frozen storage time on the aroma profile has not been studied. For this purpose, the volatile profiles of wheat bread frozen for 1, 2 and 4weeks were analysed employing solvent extraction and static headspace methoologies with GC/MS.

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