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Acrylamide (AA) is a food contaminant in thermally processed products that is object of tight control. A simple and easy-to-apply methodology for routine monitoring of AA levels in food products could allow producers to be players in the control of their own products. In this work, a simple methodology for AA quantification without derivatization was developed for biscuits, for which the benchmark levels recommended by EFSA are 350 µg/kg, and 150 µg/kg for biscuits for infants and young children. Headspace-solid phase microextraction (HS-SPME) was used in 120 mL screwed-cap vials with a carboxen/polydimetylsiloxane fiber, 4 g of biscuits, and 10 mL of water during 15 min at room temperature under stirring. The addition of 30 mL of propanol under stirring during 15 min at room temperature and 15 min at 60 °C was used to promote AA transfer to the headspace. The fiber exposure was 45 min. A gas chromatography-mass spectrometry analysis allowed to obtain an external calibration curve at m/z 71, with linearity R2 &gt, 0.99 and precision RSD &lt, 9%. The detection and quantification limits were 27.4 µg/kg and 91.5 µg/kg, respectively. The methodology was successfully used in biscuits with lower AA amount, where mitigation strategies (asparaginase or pectate) were applied.

Coffee infusion experiments were conducted to infer how operational variables (time, temperature, mass to volume ratio, and grinding) might affect the efficiency and/or selectivity of compounds extraction. Although the different variables have extensively been reported independently, to the best of our knowledge, no experimental design was yet delineated to study the simultaneous effect of variables in coffee composition. This study fulfills this gap by constructing surface models that reflect the responses in a wide-ranging design space. The freeze-dried extracts were compared regarding the overall yield of extraction, carbohydrate content and composition, caffeine, chlorogenic acid (5-CQA) content, color, and viscosity. Temperature was the major factor for coffee extracts differentiation, regarding both overall and carbohydrates yield and composition. The extraction process efficiency is more related to galactomannans extraction than arabinogalactans. Varying operational conditions, coffee extracts with distinct chemical properties are obtained from the same roasted coffee, broadening their applications in food formulations., Thanks are due to the University of Aveiro and FCT/MCT for the financial support for the QOPNA research Unit (FCT UID/QUI/00062/2019) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement, and to the Portuguese NMR Network. Guido R. Lopes and Cláudia P. Passos were supported by individual doc (SFRH/BD/104855/2014) and post-doc (SFRH/BDP/107881/2015) grants by FCT, respective, info:eu-repo/semantics/publishedVersion

The main route for acrylamide formation is the reaction between reducing sugars and asparagine. As foods pH modulates acrylamide formation, cooking under the lowest pH is a possible mitigation strategy, as long as it does not compromise the expected foods sensorial characteristics. Polymeric acid compounds, such as pectin or pectate, which are acidic polysaccharides, can provide acidity without significant interference in taste or colour. To prove this hypothesis, biscuits were prepared with tartaric acid (control to acidic effect), and galacturonic acid in monomeric (GalA), oligomeric, and polymeric forms (pectin or pectate). While 1% GalA leads to 95% increase in acrylamide, biscuits prepared with 5% pectin had a 67% decrease. Replacing sucrose with fructose increased the acrylamide levels in control biscuits above the benchmark level of 150 μg/kg recommended by EFSA for children. However, addition of pectin/pectate had an effective acrylamide mitigation by lowering its content below these indicative values.

Satureja montana is a worldwide consumed aromatic plant whose essential oils (EOs) are used as spice and preservative by food industry. Only the leaves are marketed, generating a large amount of stems as byproducts. It is possible that the EOs present in these byproducts represent a source of compounds with antimicrobial activity, as observed for the leaves. In this work, dried S. montana byproducts were used to extract EOs. Although differences were observed for the harvest year (0.42 ± 0.11 mg/g in 2016 and 0.14±0.07 mg/g in 2017), monoterpenoids were the major components, accounting for 84.4 to 97.6%, being carvacrol the most abundant component (825 – 950 μg/mg). Sesquiterpenoids accounted for 0.3 to 0.5%. Similar EOs yield and composition were obtained using solvent-free microwave extraction (16 min using 100 g of S. montana stems, previously, soaked in water and drained) or hydrodistillation (120 min using 1000 mL of water/ 100 g of dried S. montana stems). The in vitro minimal inhibitory concentrations (MICs) of S. montana EOs against Escherichia coli ATCC 25922, Salmonella enterica sv Anatum SF2, and Staphylococcus aureus ATCC 6538, which belong to pathogenic species with economic impact in poultry industry, were 225 μg/mL, 250 μg/mL, and 150 μg/mL, respectively. As these MICs are similar to the ones reported for carvacrol against the same or related strains, it can be concluded that carvacrol is the active compound in S. montana byproducts. published

This work studies the microwave-assisted extraction conditions for recovery of polysaccharides from spent coffee grounds, including their effect on arabinogalactans and galactomannans polymerization and branching structural features. Temperature (140, 170, and 200 °C) has the most significant impact on total extracted mass (ηtotal soluble solids) and sugars yield (ηsugars), arabinogalactans (ηAG) and galactomannans (ηGM), and polysaccharide mass ratio (ηAG/ηGM). Time (2, 5, and 10 min) and alkali (diluted 0.1 M NaOH) treatments have less influence. Alkali treatment and shorter time (2 min) provided a protective effect against polysaccharides degradation. At 170 °C, the yield of arabinogalactans was found to be significantly higher than that of galactomannans (ηAG/ηGM >1). Increasing temperature to 200 °C leads to decrease the polymerization of polysaccharides, promoting the formation of debranched polysaccharides and oligosaccharides. This study shows that the optimum conditions for polysaccharides extraction cannot be selected only by mass yield but need to be defined according to the desired structural features for the specific applications.

The data presented here are related to the research paper entitled “Structural features of spent coffee grounds water-soluble polysaccharides: towards tailor-made microwave assisted extractions” [1]. Microwave assisted extraction conditions were applied to spent coffee grounds for recovery of polysaccharides, namely arabinogalactans and galactomannans. Following an experimental design testing temperature, time, and alkali conditions as influence factors during microwave assisted extraction, this article reports the response data for the total extracted mass, sugars yield (including arabinogalactans and galactomannans total content, and mass ratio), and structural features (including degree of polymerization and degree of branching) for each set of operating conditions. In addition, it provides gas chromatography–mass spectrometry (GC–MS) chromatograms (and respective GC–MS spectra) of arabinogalactan and galactomannan mixtures with different structural features corresponding to representative microwave treatment conditions. Keywords: Coffee residue, Arabinogalactans, Galactomannans, Polysaccharides, Methylation analysis, Microwave assisted extraction

Grape seeds are among the main constituents of grape pomace, ranging between 20% and 30% of the wet matrix; however, their oligosaccharide composition has not been studied. This paper describes the purification and the identification of low molecular weight oligosaccharides contained in an EtOH/water extract of grape seeds. A sequential two-step purification by size exclusion chromatography was carried out to fractionate compounds according to molecular weights. Chemical characterization of the combined fractions was performed by Magnetic Resonance Spectroscopy and Gas Chromatography-Mass Spectrometry analyses. The separation process gave two fractions abundant in sucrose and glucose. A third fraction containing trisaccharides was acetylated allowing the purification of the main trisaccharide. The structure elucidation of the acetylated product made it possible to identify gentianose, a predominant carbohydrate reserve found in the storage roots of perennial Gentiana lutea. Grape seeds are wine industry by-products and the obtained results suggest the importance of their recovery.

Coffee brews have High Molecular Weight (HMW) compounds with described immunostimulatory activity, namely polysaccharides and melanoidins. Melanoidins are formed during roasting and are modified during brews technological processing. In addition, brews have Low Molecular Weight (LMW) compounds, namely free chlorogenic acids and caffeine, with well-known anti-inflammatory properties. However, this study shows that both espresso and instant coffee brews did not present immunostimulatory neither anti-inflammatory in vitro activities. It is possible that the simultaneous existence of compounds with antagonistic effects can mitigate their individual effects. To test this hypothesis, an ultrafiltration separation process was applied, studying the behavior of coffee brews’ HMW on retention of LMW compounds. Several ultrafiltration sequential cycles were required to separate retentates from LMW compounds, suggesting their retention. This effect was higher in instant coffee, attributed to its initial higher carbohydrate content when compared to espresso. Separation of HMW and LMW compounds boosted their immunostimulatory (6.2–7.8 µM nitrites) and anti-inflammatory (LPS induced nitrite production decrease by 36–31%) in vitro activities, respectively. As coffee anti-inflammatory compounds are expected to be first absorbed during digestion, a potential in vivo fractionation of LMW and HMW compounds can promote health relevant effects after coffee intake.

Because of high water content, the valorisation of broccoli by-products requires dehydration that can preserve bioactive compounds. Blanching pre-treatment has been reported to improve the drying rate of broccoli. As a thermal treatment, it promotes also enzyme inactivation. Therefore, in this study, the impact of pre-dehydration blanching step, freeze-drying, air-drying at 40 °C, and microwave hydrodiffusion and gravity (MHG) dehydration on the levels of pigments, glucosinolates, and phenolics, was evaluated by UHPLC-DAD-ESI/MSn. When compared to freeze-drying, a technique known to preserve compounds, a pre-blanching step increased the extractability of both pigments and phenolics, while air-drying only retained 49% of the pigments and 70% of phenolics, both without affecting glucosinolates. However, when air-drying was preceded by blanching, less than 50% of compounds were retained. On the other hand, MHG dehydration increased the phenolics extractability by 26%, particularly that of kaempferol derivatives while also retaining the amount of the glucosinolate glucoraphanin, when compared to freeze-drying. Nevertheless, only 23% of indole glucosinolates were recovered and pigments were severely reduced, with lutein accounting only for 32% and only chlorophyll b was observed in trace amounts after MHG dehydration. Therefore, to valorise broccoli by-products as ingredients, different drying technologies may be used when targeting different composition richness: freeze-drying is suitable for pigments and glucosinolates, air-drying is suitable for glucosinolates, while MHG promotes the extractability of phenolic compounds.

Melanoidins are high molecular weight brown compounds containing nitrogen, defined as end products of Maillard reaction. Coffee brews, prepared from roasted and ground coffee beans, are one of the main sources of melanoidins in the human diet. Polysaccharides, proteins, chlorogenic acids, and sucrose are involved in coffee melanoidins formation. Several biological activities have been attributed to coffee melanoidins, such as antioxidant, antimicrobial, anticariogenic, anti-inflammatory, antihypertensive, and antiglycative activities. To understand their potential health benefits, it is essential to know their chemical structures. However, there are several unanswered questions about the exact structures of coffee melanoidins and mechanisms involved in their formation. All these aspects, as well as the strategies that have been used for quantitation, isolation, and purification of coffee melanoidins, will be addressed in this chapter.

Polysaccharides are the predominant carbohydrates present in green coffee beans, accounting for about 50% of their dry weight. Galactomannans, type II arabinogalactans, and cellulose are the most abundant ones. Coffee galactomannans are composed of a main backbone of (β1 → 4)-linked d-mannose residues, some of them substituted at O-6 by single residues of α-d-galactose or l-arabinose, and at O-2 and/or O-3 by acetyl groups. Also, (β1 → 4)-linked d-glucose residues are components of the mannan backbone. Coffee arabinogalactans are composed of a main backbone of (β1 → 3)-linked d-galactose residues, some of them substituted at O-6 with short chains of (β1 → 6)-linked d-galactose residues. These short chains are substituted with various combinations of α-l-arabinose, α-l-rhamnose, and β-d-glucuronic acid residues. The structure of coffee galactomannans and arabinogalactans is changed during the roasting process, namely by the occurrence of depolymerization, debranching, dehydration, isomerization, and polymerization (via non-enzymatic transglycosylation) reactions. The occurrence of non-enzymatic transglycosylation reactions involving galactomannans and arabinogalactans results in arabinogalactan–galactomannan hybrid polysaccharides. During coffee roasting, galactomannans and arabinogalactans, as well as sucrose, are also involved in the formation of high molecular weight brown compounds known as melanoidins, compounds that have been associated with health benefits of coffee consumption.

An instant coffee fraction, rich in arabinogalactans, obtained by ultrafiltration, using 1 and 5 kDa membranes, has previously shown in vitro stimulatory activity on BALB/c mice spleen B lymphocytes. The compounds inducing lymphocytic activation were shown to elute, mainly near the void volume by size-exclusion chromatography, using Bio-Gel P6 (1–6 kDa). Treatment of the compounds with chymotrypsin, a digestive protease, did not affect the induced B lymphocyte activation. On the contrary, hydrolysis with an α- l -arabinofuranosidase, removing single terminally-linked arabinose residues, decreased the extent of B cell activation. The immunostimulatory activity of these compounds was also observed by in vitro experiments, using bone marrow-derived macrophages and dendritic cells as responders. Altogether, these results show the relevance of single arabinose residues, present at the non-reducing end of polymeric compounds, to the coffee stimulatory activity in cells mediating innate and acquired immunity.

(1) Background: Cholesterol bioaccessibility is an indicator of cholesterol that is available for absorption and therefore can be a measure of hypocholesterolemic potential. In this work, the effect of commercial espresso coffee and coffee extracts on cholesterol solubility are studied in an in vitro model composed by glycodeoxycholic bile salt, as a measure of its bioaccessibility. (2) Methods: Polysaccharide extracts from coffees obtained with different extraction conditions were purified by selective precipitation with ethanol, and their sugars content were characterized by GC-FID. Hexane extraction allowed us to obtain the coffee lipids. Espresso coffee samples and extracts were tested regarding their concentration dependence on the solubility of labeled 13C-4 cholesterol by bile salt micelles, using quantitative 13C NMR. (3) Results and Discussion: Espresso coffee and coffee extracts were rich in polysaccharides, mainly arabinogalactans and galactomannans. These polysaccharides decrease cholesterol solubility and, simultaneously, the bile salts’ concentration. Coffee lipid extracts were also found to decrease cholesterol solubility, although not affecting bile salt concentration. (4) Conclusions: Coffee soluble fiber, composed by the arabinogalactans and galactomannans, showed to sequester bile salts from the solution, leading to a decrease in cholesterol bioaccessibility. Coffee lipids also decrease cholesterol bioaccessibility, although the mechanism of action identified is the co-solubilization in the bile salt micelles. The effect of both polysaccharides and lipids showed to be additive, representing the overall effect observed in a typical espresso coffee. The effect of polysaccharides and lipids on cholesterol bioaccessibility should be accounted on the formulation of hypocholesterolemic food ingredients., Nutrients, 12 (2), ISSN:2072-6643

Ammonia caramels are the most common antioxidant colour agent used in bakery formulations, although their high sugars content. An alternative could be coffee melanoidins, which are brown coloured compounds with antioxidant properties, readily available from instant coffee. However, high caffeine content is limiting its direct application. To evaluate the possibility of obtaining coloured melanoidin-rich, sugars- and caffeine-poor fractions from instant coffee, in this work, simple procedures based on their ethanol insolubility (fraction EtPp) or retention by ultrafiltration (fraction HWSn) were exploited. Melanoidins incorporation into biscuits formulation (amounts of 1, 5 and 10% w/w related to flour content) resulted in acceptable coloured products with higher antioxidant activity. The biscuits supplemented with 1% EtPp or HWSn had a low caffeine content. The caffeine of one espresso coffee was equivalent to 130 biscuits containing EtPp and 31 biscuits containing HWSn. Besides, both fractions did not promote extra formation of acrylamide or 5-hydroxymethylfurfural during baking.

In this work, the supercritical fluid extraction of grape seed oil has been studied at 180, 200 and 220 bar, and 313.15 and 323.15 K to analyse their influence upon oil quality. The extraction curves exhibit an initial linear extraction period followed by a smooth asymptotic plateau at 11.5%. The extraction rate increases with increasing pressure and decreasing temperature, due to the influence of pressure and temperature upon the oil solubility; the convective mass transfer coefficient played a minor role on the process. The triacylglycerides content and the fatty acids profile have been determined, being roughly unaffected by the operating conditions adopted. The antioxidant activity of the oil has been assessed by the DPPH spectrophotometric method, and showed to increase with pressure and noticeably with temperature. Along extraction curves, the antioxidant activity is more pronounced on the oil collected during the first stages of the process, where 35–40% of total oil is extracted.

The supercritical fluid extraction of grape seed (Vitis vinifera L.) oil using carbon dioxide has been carried out at constant temperature (313.15 K) and solvent flow rate (1.7 × 10−4 kg s−1), at 160, 180 and 200 bar, using both untreated and enzymatically pre-treated seeds. The pre-treatment of triturated seeds has been performed with a cell wall degrading enzyme cocktail containing cellulase, protease, xylanase, and pectinase, in order to enlarge the broken/intact cells ratio, thus increasing oil availability. The maximum extraction yield obtained was 16.5%, which is 44% higher than the 11.5% yield obtained with untreated seeds. The cumulative extraction curves measured show two characteristic periods: a first linear part where the majority of the oil is obtained, and a second asymptotic branch which contributes with only 3–8% to the total oil removed. As pressure rises, the mass of CO2 needed to reach a definite extraction yield decreases and the linear part of the extraction curves of treated and untreated seed approach themselves.

In this work, procyanidins were extracted with methanol from the seeds of white and red grape varieties, and fractionated using graded methanol/chloroform precipitation in order to obtain the oligomers of lower molecular weight. These were analyzed by electrospray ionization-mass spectrometry (ESI-MS and ESI-MS/MS) in the positive mode. Protonated molecules, [M+H] + , of procyanidin species of nongalloylated and monogalloylated type-A and type-B oligomers, with degree of polymerisation 2–5, and digalloylated oligomers, with degree of polymerisation 2–3, were observed in the ESI-MS spectra. Type-A procyanidin abundance accounted for 60–80% of the abundance of the corresponding type-B species. Independent of the interflavanic linkage, the abundance of monogalloylated dimers accounted for 20% of the abundance of the corresponding nongalloylated ones. For the higher degrees of polymerisation, the abundance of galloylated oligomers was shown to reach up to 60% of the abundance of the corresponding nongalloylated oligomers. Thiolytic analyses showed that the type-A interflavanic linkages were present in the terminal units whereas the type-B interflavanic linkages were present as extension units. Although many reports are already available regarding the analyses of procyanidin polymers and grape seed procyanidins, this is the first report for the occurrence of type-A galloylated procyanidins. The similarity of the relative abundances and structural features observed in the samples of both white and red grape varieties, shows that these are characteristic of grape seeds. 2007 Elsevier Ltd. All rights reserved.

Two equations of state (PC-SAFT and CPA) are used to predict the monomer fraction of pure associating fluids. The models each require five pure-component parameters usually obtained by fitting to experimental liquid density and vapor pressure data. Here we also incorporate monomer fractions measured using spectroscopy, resulting in models that better predict the monomer fraction (fraction of molecules not participating in hydrogen bonding), without sacrificing the accuracy of the liquid density and vapor pressure correlations. Thus, it is clear that monomer fraction prediction depends on the way the parameters were obtained. The selection of appropriate association schemes is also investigated using spectroscopic data. For pure water a four-site scheme is shown to be the most appropriate scheme. In the case of pure alcohols, a three-site scheme is best for methanol; two- or three-site schemes perform about equally for ethanol; for higher alcohols a two-site scheme is preferred. This is in accordance with ...

Arabinose from arabinogalactan side chains was hypothesized as a possible binding site for chlorogenic acids in coffee melanoidins. To investigate this hypothesis, a mixture of 5-O-caffeoylquinic acid (5-CQA), the most abundant chlorogenic acid in green coffee beans, and (alpha 1 -> 5)-L-arabinotriose, structurally related to arabinogalactan side chains, was submitted to dry thermal treatments. The compounds formed during thermal processing were identified by electrospray ionization mass spectrometry (ESI-MS) and characterized by tandem MS (ESI-MSn). Compounds composed by one or two CQAs covalently linked with pentose (Pent) residues (1-12) were identified, along with compounds bearing a sugar moiety but composed exclusively by the quinic or caffeic acid moiety of CQAs. The presence of isomers was demonstrated by liquid chromatography online coupled to ESI-MS and ESI-MSn. Pent(1-2)CQA were identified in coffee samples. These results give evidence for a diversity of chlorogenic acid arabinose hybrids formed during roasting, opening new perspectives for their identification in melanoidin structures. (C) 2015 Elsevier Ltd. All rights reserved.

Aiming to investigate the possible occurrence of transglycosylation reactions between galactomannans and side chains of arabinogalactans during coffee roasting, mixtures of β-(1→4)- d -mannotriose and α-(1→5)- l -arabinotriose were subjected to dry thermal treatments at 200 °C. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis allowed identifying polysaccharides composed by pentose and hexose residues with a degree of polymerization up to 18 residues. Methylation analysis showed the occurrence of new types of glycosidic linkages in all thermally treated mixtures, as well as the occurrence of terminally and 5-linked ribose, possibly formed from arabinose isomerization. Also, xylose and lyxose were identified and proposed to be formed from mannose. These results support the occurrence of transglycosylation reactions promoted by roasting involving both oligosaccharides in the starting mixtures, resulting in arabinan and mannan chimeric polysaccharides. These structural features were also found in roasted coffee polysaccharide samples.

The feasibility of using sequential microwave superheated water extraction (MAE) for the recovery of mannans from spent coffee grounds (SCG) was studied. Due to the high contents of mannose still present in the SCG residue left after two consecutive MAE, the unextracted material was re-suspended in water and submitted to a third microwave irradiation (MAE3) at 200 degrees C for 3 min. With MAE3, mannose recovery achieved 48%, increasing to 56% by MAE4, and reaching a maximum of 69% with MAE5. Glycosidic-linkage analysis showed that in MAE3 mainly galactomannans were recovered, while debranched galactomannans were recovered with MAE4 and MAE5. With increasing the number of extractions, the average degree of polymerization of the mannans decreased, as observed by size-exclusion chromatography and by methylation analysis. Scanning electron microscopy images showed a decrease on cell walls thickness. After final MAE5, the remaining un-extracted insoluble material, representing 22% of the initial SCG, was composed mainly by cellulose (84%). (C) 2013 Elsevier Ltd. All rights reserved.

The reported work aimed at the optimization of operating conditions of the supercritical fluid extraction (SFE) of spent coffee grounds (SCG) using pure or modified CO2, with particular emphasis on oil enrichment with diterpenes like kahweol, cafestol and 16-O-methylcafestol. The analysis comprised the application of Box-Behnken design of experiments and response surface methodology, and involved three operating variables: pressure (140-190 bar), temperature (40-70 degrees C) and cosolvent (ethanol) addition (0-5 wt.%). The best conditions to maximize total extraction yield are 190 bar/55 degrees C/5 wt.% EtOH, leading to 11.97% (g(oil)/100 g(SCG)). In terms of the concentration of diterpenic compounds in the supercritical extracts, the best operating conditions are 140 bar/40 degrees C/0 wt.% EtOH, providing 102.90 mg g(oil)(-1). The measurement of extraction curves near optimized conditions (140 bar/55 degrees C/0 wt.% EtOH and 190 bar/55 degrees C/0 wt.% EtOH) confirmed the trends of the statistical analysis and revealed that SFE enhances diterpenes concentration by 212-410% at the expenses of reducing the extraction yield between 39% and 79% in comparison to n-hexane extraction. (C) 2013 Elsevier B.V. All rights reserved.

Inhibition of the angiotensin I converting enzyme (ACE) is an important therapeutic approach in the treatment of several cardiovascular disorders. In this study the inhibitory potential of procyanidin-rich fractions of grape seed (Vitis vinifera L.) was evaluated. The inhibitory capacity was assayed by fluorometric determination of the amount of histidyl-leucine released from the substrate utilized in the presence of ACE from rabbit lung. Four purified monomers [(+)-catechin, (-)-epicatechin, (+)-catechin-O-gallate, and (-)-epigallocatechin] were also tested for comparison. Results showed that the natural phenolic extracts exhibit higher inhibitory potential than the monomers, and that fractions with higher average degrees of polymerization (DPn = 8, IC50 = 0.1 mg/L) present lower IC50 than the intermediate ones (DPn = 5, IC50 = 3.5 mg/L). Such findings strengthen the idea that the inhibitor extension, and the number of heterocyclic oxygen and hydroxyl groups in their structures, could define their in vitro action. (C) 2013 Elsevier Ltd. All rights reserved.