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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 coffee industry generates a wide variety of by-products derived from green coffee processing (pulp, mucilage, parchment, and husk) and roasting (silverskin and spent coffee grounds). All these fractions are simply discarded, despite their high potential value. Given their polysaccharide-rich composition, along with a significant number of other active biomolecules, coffee by-products are being considered for use in the production of plastics, in line with the notion of the circular economy. This review highlights the chemical composition of coffee by-products and their fractionation, evaluating their potential for use either as polymeric matrices or additives for developing plastic materials. Coffee by-product-derived molecules can confer antioxidant and antimicrobial activities upon plastic materials, as well as surface hydrophobicity, gas impermeability, and increased mechanical resistance, suitable for the development of active food packaging. Overall, this review aims to identify sustainable and eco-friendly strategies for valorizing coffee by-products while offering suitable raw materials for biodegradable plastic formulations, emphasizing their application in the food packaging sector.

All coffee brews are prepared with roasted coffee and water, giving origin to espresso, instant, or filtered coffee, exhibiting distinct physicochemical properties, depending on the extraction conditions. The different relative content of compounds in the brews modulates coffee body, aroma, and colour. In this study it was hypothesized that a coffee infusion allows to obtain extracts that resemble espresso coffee (EC) physicochemical properties. Carbohydrates (content and composition) were the target compounds as they are organoleptically important for EC due to their association to foam stability and viscosity. The freeze-drying of the extracts allowed better dissolution properties than spray-drying. Instant coffee powders were obtained with chemical overall composition resembling espresso, although with lower lipids content. The extracts were able to produce the characteristic foam through CO2 injection or salts addition. Their redissolution at espresso concentration allowed a viscosity, foamability and volatile profile representative of an espresso coffee, opening new exploitation possibilities., 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) and the LAQV-REQUIMTE (UIDB/50006/2020) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement. The authors thank FCT co-financed by Programa Operacional Competitividade e Internacionalização, Portugal 2020 and União Europeia by the FEDER (FCT - Compete2020 - Portugal 2020 – FEDER/EU) N° POCI-01-0145-FEDER-029560, project “PulManCar”. Guido R. Lopes was supported by an individual doctoral grant by FCT (SFRH/BD/104855/2014). Sílvia Petronilho (SFRH/BPD/117213/2016) and Cláudia P. Passos (CEECIND/00813/2017) also thanked FCT for the Post-doc grant and the assistant research contract, respectively. The authors thank Prof. Margarida Almeida for the use of spray-drying facilities and Ana Bastos for the help in the equipment operation., 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.

Polysaccharides can be elite carriers for therapeutic molecules due to their versatility and low probability to trigger toxicity and immunogenic responses. Local and systemic therapies can be achieved through particle pulmonary delivery, a promising non-invasive alternative. Successful pulmonary delivery requires particles with appropriate flowability to reach alveoli and avoid premature clearance mechanisms. Polysaccharides can form micro-, nano-in-micro-, and large porous particles, aerogels, and hydrogels. Herein, the characteristics of polysaccharides used in drug formulations for pulmonary delivery are reviewed, providing insights into structure-function relationships. Charged polysaccharides can confer mucoadhesion, whereas the ability for specific sugar recognition may confer targeting capacity for alveolar macrophages. The method of particle preparation must be chosen considering the properties of the components and the delivery device to be utilized. The fate of polysaccharide-based carriers is dependent on enzyme-triggered hydrolytic and/or oxidative mechanisms, allowing their complete degradation and elimination through urine or reutilization of released monosaccharides.

Single-dose coffee capsules have revolutionized the coffee market, fueling espresso coffee popularity and offering access to a wide selection of coffee blends. Nevertheless, scarce information related to coffee powder and brew’s combined volatile characterization is available. In this study, it is hypothesized that coffee brew aroma characteristics can be predicted based on coffee powder’s volatile composition. For this, headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC × GC-ToFMS) was used. The data were combined via chemometric tools to characterize in depth the volatile composition of eight blends of capsule-coffee powder and respective espresso brews, simulating the consumer’s perception. A total of 390 volatile compounds were putatively identified, 100 reported for the first time in roasted coffee or brews. Although the same chemical families were determined among the coffee powders and espresso brews, a different volatile profile was determined for each matrix. The Pearson correlation of coffee powders and respective brews allowed to identify 15 volatile compounds, mainly terpenic and esters recognized by their pleasant notes, with a strong relationship between the amounts present in both matrices. These compounds can be key markers to predict the volatile aroma potential of an espresso brew when analyzing the coffee powder.

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

Apple pomace valuation has been impaired by its high perishability and absence of fast drying approaches demanded by industry. This work aimed to assess the feasibility of Microwave Hydrodiffusion and Gravity (MHG) process applied for apple pomace drying using discrete delivery powers (300–900 W) and comparison with hot-air drying (40–100 °C). To dry 0.4 kg of apple pomace (81% moisture), hot-air drying required 3.6–9.9 h with estimated water evaporation flux of 1.0–3.5 mL/min. For MHG, which processed 1.2 kg, these corresponded to 1.0–2.6 h and 5.1–13.9 mL/min. Furthermore, MHG allowed water recovery containing part of apple pomace phenolic compounds and carbohydrates. The dried pomace was stable for 2 years, after which phenolic compounds and polysaccharides were still recoverable by hot water extractions. These results pave the way for MHG to be used for apple pomace and other by-products preservation, boosting their conversion into valuable co-product for valuation of its components.

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.

Single-dose coffee capsule system is a technology used to prepare espresso coffee which offers consumers the possibility to choose among several blends. However, the characterization of espresso coffees extracted with these systems, namely regarding polysaccharides structures and melanoidin content, is scarce. In order to define a carbohydrate and melanoidin composition pattern for single-dose espresso coffee base blends, a range of 6 commercial espresso coffee blends was studied. In addition, a decaffeinated blend and a blend supplemented with plant natural extracts were also included. The base blends showed galactomannans as the predominant polysaccharides over arabinogalactans, on the contrary of the decaffeinated blend. The blend supplemented with natural plant extracts showed glucose-rich polysaccharides. The labelled intensity of coffee single-dose seems to be related with the unknown brown compounds of melanoidins, present in the high molecular weight material of the brews. A pattern could be obtained for single-dose espresso coffee base blends, presenting an average per cup of 1.21 g of total solids and 242 mg of soluble dietary fibre, constituted by 62 mg of galactomannans and 48 mg of arabinogalactans, and 123 mg of melanoidins. On average, 46% of espresso coffee low molecular weight compounds are adsorbed to the high molecular weight material, evidencing the importance of the adsorption/desorption phenomena for the properties of coffee dietary fibre.

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.

Immunostimulatory polysaccharides are compounds capable of interacting with the immune system and enhance specific mechanisms of the host response. Glucans, mannans, pectic polysaccharides, arabinogalactans, fucoidans, galactans, hyaluronans, fructans, and xylans are polysaccharides with reported immunostimulatory activity. The structural features that have been related with such activity are the monosaccharide and glycosidic-linkage composition, conformation, molecular weight, functional groups, and branching characteristics. However, the establishment of structure-function relationships is possible only if purified and characterized polysaccharides are used and selective structural modifications performed. Aiming at contributing to the definition of the structure-function relationships necessary to design immunostimulatory polysaccharides with potential for preventive or therapeutical purposes or to be recognized as health-improving ingredients in functional foods, this review introduces basic immunological concepts required to understand the mechanisms that rule the potential claimed immunostimulatory activity of polysaccharides and critically presents a literature survey on the structural features of the polysaccharides and reported immunostimulatory activity.

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

This work addresses scientific and techno-economic aspects of supercritical fluid extraction (SFE) of spent coffee grounds which are of interest under the biorefinery context. Soxhlet experiments were carried out and SFE curves were measured at 190 bar and 40 degrees C/55 degrees C. The extracts were characterized by GC-FID, and the triacylglycerides profiles were almost constant along an extraction curve, and similar to the n-hexane Soxhlet results: linoleic and palmitic acids content in both extracts are 44.5 and 37.5% (wt.), respectively. The oil solubility, intraparticle diffusion, convective mass transfer coefficient, and oil removal flux (this one estimated for infinite dilution) were calculated and discussed in detail in the ranges of operating conditions under analysis. It was concluded that solubility is the chief parameter behind the distinct cumulative extraction curves, and that all experiments are subjected to equivalent mass transfer resistances. An economic analysis involving cost of manufacturing (COM) and net income calculations were performed for distinct operating conditions and unit arrangements. The optima results were obtained for an arrangement of 3 beds of 1 m(3), extraction time of 2.0 h, 300 bar, 50 degrees C and 30 kg(CO2) kg(SCG)(-1)h(-1). Under these conditions production can reach 454 ton year(-1), a cost of manufacturing (COM) around 2.4M(sic), and process net income of 56.6 M(sic). A sensitivity analysis varying the unit capacity, extraction time and precipitation pressure (extract vessel), showed the process economics to remain viable. (C) 2013 Elsevier B.V. All rights reserved.

The spent coffee grounds (SCG) are a food industry by-product that can be used as a rich source of polysaccharides. In the present work, the feasibility of microwave superheated water extraction of polysaccharides from SCG was studied. Different ratios of mass of SCG to water, from 1:30 to 1:5 (g:mL) were used for a total volume of 80 mL. Although the amount of material extracted/batch (MAE1) increased with the increase of the concentration of the sample, the amount of polysaccharides achieved a maximum of 0.57 g/batch for 1:10. Glycosidic-linkage composition showed that all extraction conditions allowed to obtain mainly arabinogalactans. When the unextracted insoluble material was re-extracted under the same conditions (MAE2), a further extraction of polysaccharides was observed (0.34 g/batch for 1:10), mainly galactomannans. Also, a high amount of oligosaccharides, mainly derived from galactomannans, can be obtained in MAE2 (0.96 g/batch for 1:10). This technology allows to obtain galactomannans and arabinogalactans in proportions that are dependent on the operating conditions.

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 in a semi-continuous unit has been modelled and discussed in detail. The model embodies the concept of broken plus intact cells, and assumes series mass transfer from intact to broken cells, and then to the fluid phase. The numerical solution has been accomplished by the method of lines using finite differences with upwind flow correction. Experimental extraction curves for both untreated seed and enzymatically pre-treated seed have been modelled in order to evaluate the performance of the model in terms of correlation capability and physical meaning of the parameters. The extraction curves for untreated and treated seed have been accurately represented with average deviations between 2.30 and 7.25%. The model parameters that are intimately related with the internal structure of the seed are the grinding efficiency (or fraction of broken cells) and the internal mass transfer coefficient. Both parameters have been optimised and attained physically sound values, in view of the fact they increased after the enzymatic pre-treatment, and obeyed simple restrictions imposed. The model has been able to generate coherent concentration profiles in the bed and elution curves as well.

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 application of an enzymatic pre-treatment to increase the yield of grape seed oil extraction was studied. Experiments were carried out to measure the effects that reaction time, temperature, pH, particle size and enzyme concentration have upon the enzymatic activity. The following set of parameters was optimised: time = 24 h, pH 4, temperature 30–40 °C, particle diameters 1.0–1.4 mm, and cocktail concentration of: cellulase = 29, protease = 1191, xylanase = 21, and pectinase = 569 U/g of seed sample. The extraction yield was 13.7%, which represents an increment of 106% over non-treated samples. For 120 h the yield achieved was 17.5%, and the increment reached 163%. Such results indicate that a prolonged enzymatic treatment may certainly be used to enhance oil extraction.

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.

A mathematical model with two different methods to represent the mass transfer in the biomass matrix, (series and parallel) is proposed to simulate a supercritical extraction unit. The model is solved using the method of lines and finite differences with flow correction. Using experimental extraction curves, both models were fitted fairly well, with equivalent accuracy. Two operating regimes were detected in the selected experimental conditions: equilibrium and mass transfer controlled. The last one is more difficult to simulate, requiring specific mass transfer parameters for series and parallel alternatives, for its accurate representation.

Fourier transform infrared (FTIR) spectroscopy has being emphasised as a widespread technique in the quick assess of food components. In this work, procyanidins were extracted with methanol and acetone/water from the seeds of white and red grape varieties. A fractionation by graded methanol/chloroform precipitations allowed to obtain 26 samples that were characterised using thiolysis as pre-treatment followed by HPLC-UV and MS detection. The average degree of polymerisation (DPn) of the procyanidins in the samples ranged from 2 to 11 flavan-3-ol residues. FTIR spectroscopy within the wavenumbers region of 1800-700 cm(-1) allowed to build a partial least squares (PLS1) regression model with 8 latent variables (LVs) for the estimation of the DPn, giving a RMSECV of 11.7%, with a R(2) of 0.91 and a RMSEP of 2.58. The application of orthogonal projection to latent structures (O-PLS1) clarifies the interpretation of the regression model vectors. Moreover, the O-PLS procedure has removed 88% of non-correlated variations with the DPn, allowing to relate the increase of the absorbance peaks at 1203 and 1099 cm(-1) with the increase of the DPn due to the higher proportion of substitutions in the aromatic ring of the polymerised procyanidin molecules. The authors gratefully acknowledge Pedro Vasco (Universidade de Aveiro) and Eng. A. Dias Cardoso, Eng. José Carvalheira, and all staff from Estac¸ ão Vitivinícola da Bairrada, Portugal, for the technical support and raw material provided. Thanks are also due to Adega Cooperativa de Pinhel for providing the seed from red grapes. This work was supported by the Research Unit 62/94 QOPNA and project POCTI/EQU/47533/2002. Cláudia Passos was supported by a PhD grant by FCT, SFRH/BD/19072/2004. info:eu-repo/semantics/publishedVersion