Valorization of Grape Pomace as a Renewable Source of Techno-Functional and Antioxidant Pectins.

The food industry's increasing demand for new functional ingredients that meet both organoleptic and healthy requirements has driven the exploration of new sources of functional ingredients in agro-industrial by-products. The aim of this work was to valorize grape pomace (Vitis vinifera L. garnacha) as a source of pectins using food-grade extracting agents. Obtained pectins were evaluated for monomeric composition, methyl esterification, molecular weight, water retention, oil-holding capacity, and antioxidant properties. The relatively soft extraction conditions used permitted obtaining low methoxyl pectin (10-42%) enriched in homogalacturonan (38-45%) or rhamnogalacturonan (33-41%) with different branching degrees, molecular weight, and fewer impurities than those found in the scarce previous literature. The relationship between structure and functionality was studied. Among the different pectins obtained, the sample derived from the extraction with sodium citrate could resume the best characteristics, such as pectin purity and higher water retention and oil holding capacity. These results underscore the relevance of grape pomace as a viable alternative source of pectin.

GADL1 is a multifunctional decarboxylase with tissue-specific roles in ß-alanine and carnosine production.

Carnosine and related ß-alanine-containing peptides are believed to be important antioxidants, pH buffers, and neuromodulators. However, their biosynthetic routes and therapeutic potential are still being debated. This study describes the first animal model lacking the enzyme glutamic acid decarboxylase-like 1 (GADL1). We show that Gadl1-/- mice are deficient in ß-alanine, carnosine, and anserine, particularly in the olfactory bulb, cerebral cortex, and skeletal muscle. Gadl1-/- mice also exhibited decreased anxiety, increased levels of oxidative stress markers, alterations in energy and lipid metabolism, and age-related changes. Examination of the GADL1 active site indicated that the enzyme may have multiple physiological substrates, including aspartate and cysteine sulfinic acid. Human genetic studies show strong associations of the GADL1 locus with plasma levels of carnosine, subjective well-being, and muscle strength. Together, this shows the multifaceted and organ-specific roles of carnosine peptides and establishes Gadl1 knockout mice as a versatile model to explore carnosine biology and its therapeutic potential.

Evaluation of carbohydrates and quality parameters in six types of commercial teas by targeted statistical analysis.

The content of low molecular weight carbohydrates (LMWC) of six types of tea produced from the leaves of Camellia sinensis were analyzed by hydrophilic interaction chromatography (HILIC) coupled to mass spectrometry. Quantities of sucrose, glucose, fructose, myo-inositol, maltose, mannitol, raffinose, galactinol, and stachyose were determined in samples of white, yellow, green, black, oolong, and dark tea. Sucrose was the most abundant carbohydrate in all types of tea. The concentration of all measured carbohydrates except mannitol was lowest in dark tea samples. Correlation analyses using quantitative data of LMWCs, antioxidant activity, and color parameters were performed on black tea samples to evaluate the interaction of different quality parameters. Carbohydrates depletion was observed during tea processing with formation of Amadori compounds with theanine.

Monitoring the changes in low molecular weight carbohydrates in cocoa beans during spontaneous fermentation: A chemometric and kinetic approach.

The low molecular weight carbohydrate (LMWC) profile has recently been investigated, showing considerable changes between fermented and unfermented cocoa beans. These differences are a consequence of the fermentation process, which is considered a crucial step in chocolate production. During fermentation, LMWC are involved in Maillard reaction, a crucial reaction for the development of aroma and taste precursors. However, there is a lack of information related to LMWC changes and of contextualization with changes in other physicochemical parameters (pH and dry matter) during spontaneous fermentation. The different approaches employed in this manuscript have allowed the identification of a sequential degradation of tetra-, tri- and disaccharides, as well as an increase in the monosaccharide content during fermentation. Moreover, a correlation was determined between some LMWC and physicochemical parameters. Besides that, the chemometric approach identified the fermentation period ranging between 48 and 96 h as determinant to produce noticeable changes in unfermented beans based on the indicators evaluated. Furthermore, different kinetic parameteres (reaction order, observed reaction rates (kobs) and half-life values (t1/2)) of different LMWC were determined, showing differences between them. The results showed in this manuscript provide unprecedented mechanistic details of spontaneous cocoa fermentation.

Changes in low molecular weight carbohydrates in kale during development and acclimation to cold temperatures determined by chromatographic techniques coupled to mass spectrometry.

Kale (Brassica oleracea) is a cool-season vegetable widely employed in the elaboration of diverse products such as tea and smoothies in USA or in the Northern German cuisine in wintertime. Besides, kale is gaining attention due to the diverse health benefits reported in the literature for its consumption, e.g. antigenotoxic and anticarcinogenic effect, protection of cardiovascular system and gastrointestinal tract. Low molecular weight carbohydrates (LMWC) are compounds directly related with kale flavour and nutritional quality. Despite different studies focusing on the chemical composition of kale, few information on LMWC is available. Thus, in this work a multianalytical approach was conducted in order to perform a comprehensive study of kale LMWC; their evolution during plant development and acclimation to cool temperatures was also evaluated. Gas chromatography coupled to mass spectrometry allowed the identification of 13 LMWC, being myo-inositol, galactinol, maltose and melibiose described for the first time in kale. Eight major LMWC were quantified in three different commercial kale cultivars using hydrophilic interaction liquid chromatography coupled to mass spectrometry to monitor possible differences in their content during plant development and as consequence of plant acclimation to cold temperatures. Overall, for all types of kales under study, the content of maltose and sucrose decreased during the plant development while the concentration of fructose, melibiose, maltose, raffinose and galactinol was increased in all kale types exposed to low temperatures. These results underline the importance of controlling the temperature during kale cultivation in order to obtain products with a high nutritional value.

Characterization of commercial green tea leaves by the analysis of low molecular weight carbohydrates and other quality indicators.

A comprehensive characterization of commercial green tea (CGT) with the employment of independent variables such as low molecular weight carbohydrates (LMWC), soluble solids, color and antioxidant capacity has been performed in this manuscript. Within the manuscript, a convenient HILIC-MS method, suitable to perform a simultaneous identification and quantification of all mono-, di-, oligosaccharides and cyclitols observed in green tea was introduced. The method covers all key analytes in a single chromatographic analysis. Fifty-six samples from different origins (n = 10) were evaluated to explore differences based on origin. In addition, commercial samples processed by pan-firing and steaming were used for comparative purposes, allowing the identification of putative processing markers. The results obtained contribute to gain a better knowledge of the variations, according to origin and processing, in composition and quality of CGT, commodity widely appreciated by the consumers.

Analysis of minor low molecular weight carbohydrates in cocoa beans by chromatographic techniques coupled to mass spectrometry.

The low molecular weight carbohydrate (LMWC) profile of cocoa beans has recently been studied using hydrophilic interaction liquid chromatography coupled to electrospray ionization-time of flight mass spectrometry (HILIC-ESI-TOF MS) and HILIC-ESI-tandem mass spectrometry (HILIC-ESI-MSn). However, different LMWC could not be unambiguously identified. Thus, as a first approach in this paper, gas chromatography coupled to mass spectrometry (GC-MS) was used as a complementary analytical technique to characterize LMWC of cocoa beans. Different mono-, di-, tri- and tetrasaccharides, as well as myo-inositol, galactinol and a diglycosil glycerol were detected. scyllo-Inositol, 1-kestose and 6-kestose were identified in unfermented cocoa beans for the first time. Moreover, other minor LMWC were tentatively assigned as fructosyl-fructose, fructosyl-glucose and glucosyl-sucrose. As a second step, in order to evaluate new possible indicators of cocoa bean origin or fermentation status, scyllo-inositol, 1-kestose and galactinol were selected as target compounds and a HILIC-ESI-TOF MS method was optimized for their analysis. The optimized conditions, using an acetonitrile:water gradient with 0.05% ammonium hydroxide at 40 °C showed narrow peaks (wh: 0.3-0.5 min) with good resolution values (Rs: 0.83-2.83). The validated HILIC-ESI-TOF MS method was applied to the analysis of 35 cocoa bean samples from different origins and fermentation status. The content of scyllo-inositol, 1-kestose and galactinol in unfermented beans (n = 21) was in the range of traces-504.9, 36.1-133.5 and traces-1970.4 µg g-1 cocoa DM respectively. In fermented beans (n = 14), the content of scyllo-inositol and 1-kestose was in the range of 15.5-491.9 and traces-115.5 µg g-1 cocoa DM respectively. Galactinol was absent in fermented beans, indicating that it could be a potential indicator of fermentation status. The methodology proposed could be used for quality control of natural products and other food ingredients containing inositols and oligosaccharides.

Profiling, quantification and classification of cocoa beans based on chemometric analysis of carbohydrates using hydrophilic interaction liquid chromatography coupled to mass spectrometry.

Fifty-six cocoa bean samples from different origins and status of fermentation were analyzed by a validated hydrophilic interaction liquid chromatography-electrospray ionization-time of flight-mass spectrometry (HILIC-ESI-TOF-MS) method. The profile of the low molecular weight carbohydrate (LMWC) was analyzed by high resolution and tandem mass spectrometry, which allowed the identification of mono-, di-, tri- and tetrasaccharides, sugar alcohols and iminosugars. This study provides, for the first time in a large set of samples, a comprehensive absolute quantitative data set for the carbohydrates identified in cocoa beans (fructose, glucose, mannitol, myo-inositol, sucrose, melibiose, raffinose and stachyose). Differences in the content of carbohydrates were observed between unfermented (range of 0.9-4.9 g/g DM) and fermented (range 0.1-0.5 g/g DM) cocoa beans. The use of multivariate statistical tools allowed the identification of biomarkers suitable for cocoa bean classification according to the status of fermentation, procedure of fermentation employed and number of days of fermentation.

Presence of galactooligosaccharides and furosine in special dairy products designed for elderly people.

An evaluation of the formation of prebiotic carbohydrates during lactose hydrolysis has been carried out in industrially elaborated dairy preparations designed for elderly people. Due to the hydrolysis of lactose, high levels of galactose and glucose were found together with galactooligosaccharides (GOS), mainly allolactose, 6-galactobiose and 6'-galactosyl lactose. Total GOS content was between 7.1% and 13.4% of total carbohydrates, depending on lactose hydrolysis extent. In addition, the determination of furosine as indicator of lysine loss during the Maillard reaction (MR) has been also studied. The high content of monosaccharides promoted the progress of the MR during UHT processing, as reflected by the levels of furosine found in samples. After storage at 20 °C for 4 months the content of furosine increased by 74-90%. These results underline the importance of controlling lactose hydrolysis, and processing and storage conditions to preserve the quality and increase the bioactivity of dairy preparations designed for elderly people.

Impact of high-intensity ultrasound on the formation of lactulose and Maillard reaction glycoconjugates.

The impact of high-intensity ultrasound (US) on the formation of lactulose during lactose isomerization and on the obtention of lysine-glucose glycoconjugates during Maillard reaction (MR) has been studied, respectively, in basic and neutral media. As compared to equivalent conventional heat treatments, a higher formation of furosine, as indicator of initial steps of MR, was observed together with more advance of the reaction in US treated samples, this effect being more pronounced with the increase of US amplitude (50-70%) and temperature (25-40 °C). Regarding the influence of US on lactulose formation, in general, in a buffered system (pH 10.0), US at 70% of amplitude and 60 °C increased the rate of lactose isomerization, higher values of lactulose, epilactose and galactose being observed in comparison to conventional heating. The results of this work showed an acceleration of both reactions by US, indicating its usefulness to promote the formation of functional ingredients.

Impact of processing conditions on the kinetic of vitamin C degradation and 2-furoylmethyl amino acid formation in dried strawberries.

In this paper, a study on the usefulness of the determination of vitamin C together with indicators of the initial steps of Maillard reaction (2-furoylmethyl amino acids, 2-FM-AA) during the convective drying of strawberries has been carried out for the first time, paying special attention to the kinetics of degradation and formation, respectively, of both parameters. Formation of 2-FM-AA of Lys, Arg and GABA and vitamin C loss increased with time and temperature following, respectively, a zero and first-order kinetics. As supported by its lower activation energy, 2-FM-GABA (55.9 kJ/mol) and 2-FM-Lys+2-FM-Arg (58.2 kJ/mol) were shown to be slightly more sensitive indicators than vitamin C (82.1 kJ/mol). The obtained results, together with a complementary study on the rehydration ability and sensorial attributes of samples, pointed out the suitability of the convective drying system to obtain dried strawberries of high nutritive quality and bioactivity and good consumer acceptance.

Survey of quality indicators in commercial dehydrated fruits.

Physical and chemical quality parameters (dry matter, aw, protein, carbohydrates, vitamin C, 2-furoylmethyl amino acids, rehydration ratio and leaching loss) have been determined in 30 commercial dehydrated fruits (strawberry, blueberry, raspberry, cranberry, cherry, apple, grapefruit, mango, kiwifruit, pineapple, melon, coconut, banana and papaya). For comparison purposes, strawberry samples processed in the laboratory by freeze-drying and by convective drying were used as control samples. Overall quality of dehydrated fruits seemed to be greatly dependent on processing conditions and, in a cluster analysis, samples which were presumably subjected to osmotic dehydration were separated from the rest of fruits. These samples presented the lowest concentration of vitamin C and the highest evolution of Maillard reaction, as evidenced by its high concentration of 2-furoylmethyl amino acids. This is the first study on the usefulness of this combination of chemical and physical indicators to assess the overall quality of commercial dehydrated fruits.

Determinación de triptasa en el líquido de una ampolla en un caso de mastocitosis cutánea eritrodérmica difusa / Tryptase determination in blister fluid in a case of diffuse cutaneous mastocytosis

El objetivo de este trabajo es describir la utilidad de la determinación de la triptasa del líquido de una ampolla, como marcador del grado de liberación local de mediadores mastocitarios, en una mastocitosis cutánea eritrodérmica difusa, durante un episodio agudo de liberación que cursa con la formación de estas lesiones. La determinación de la triptasa sérica se emplea en las mastocitosis de forma rutinaria, ya que está relacionada con el grado de infiltración mastocitaria (carga mastocitaria) así como con la activación y posterior liberación de mediadores mastocitarios. Cuando esta determinación se realiza en el líquido de una ampolla, indica el grado de infiltración de la piel por mastocitos y de liberación de mediadores mastocitarios a nivel cutáneo (AU)

Serum tryptase determination is usually performed in mastocytosis, as in most cases it can predict mast-cell burden and/or mast-cell activation. Tryptase values in blister fluids are correlated with dermal mast-cell numbers and local mast-cell activation. The aim of this report is to describe the usefulness of tryptase determination in blister fluid as a marker of mast-cells mediators release in diffuse erythrodermic cutaneous mastocytosis (AU)