Pomace Samples Research Articles

Compositions and chemical variability of grape pomaces from French vineyard

Compositions of 8 pomace samples originating from red and white winemaking from different areas of production of French vineyard were characterized (Alsace, Bordeaux, Bourgogne, Champagne, Languedoc, Val de Loire and Provence). Large variabilities were observed depending on cultivar and grape varieties: pomace samples contained 3–6% w/w of oil and 20–46% w/w of sugars, mainly glucans and xyloglucans with a relatively low pectinaceous polysaccharides content. Condensed tannins accounted for 20–51% w/w and can be extracted in an aqueous medium. The reactivity of some of these extracts toward formaldehyde (through gel time analysis) demonstrated their promising properties for adhesive applications. The results obtained in the present study confirm that grape pomace constitutes a promising source for a valuable utilization of this by-product.

Design and Optimization of a Semicontinuous Hot–Cold Extraction of Polyphenols from Grape Pomace

Grape pomace contains appreciable amounts of polyphenolic compounds such as anthocyanins and procyanidins which can be recovered for use as food supplements. The extraction of these polyphenols from the pomace is usually accomplished at slightly elevated temperatures, frequently employing hydroethanolic solvents. Due to governmental regulations and the cost involved in using ethanol as a solvent, as well as the loss in polyphenolics due to thermal degradation, improved extraction techniques are required. In this study, a semicontinuous extraction apparatus employing only water was developed to maximize the recovery of anthocyanins and procyanidins from red grape pomace (Vitis vinifera). Water is preheated prior to its entry to the extraction cell containing the grape pomace sample, where it is allowed to then flow continuously through the unheated extraction vessel prior to its collection at ambient conditions. Extraction variables that impacted the polyphenolic recovery included pomace moisture content (crude or dried), sample mass, water flow rate, and extraction temperature. A response surface method was used to analyze the results from the extraction, and the optimal conditions were found to be 140 °C and 9 mL/min water flow rate. These conditions can produce an extract containing 130 mg/100 g DW of anthocyanins and 2077 mg/100 g DW of procyanidins. Higher yields of polyphenolics were observed using crude (wet) rather than dried pomace, hence avoiding the need to dry the pomace prior to extraction. The described semicontinuous extraction method using only water as the extraction solvent under subcritical conditions allowed the efficient extraction of polyphenols from red grape pomace without the attendant loss of polyphenolic content due to having to heat the extraction vessel prior to commencement of extraction.

Characterization and combustion of olive pomace and forest residue pellets

As a result of agroindustrial activities in southwestern Europe, a great amount of residues are generated; among them, olive pomace stands out as one of the most abundant. One interesting alternative to increase its potential as biofuel can be its densification. However, in order to achieve high quality pellets, it is necessary to blend this material with other feedstocks. In this work, the properties of blends of pelletized residues from olive pomace and pyrenean oak were analyzed with a view to find the best option.In order to compare the characteristics of the obtained pellets, such as moisture content, mechanical durability, ash content and calorific value, these parameters were determined according to the Technical Specifications for Solid Biofuels CEN/TS. Moreover, the pellets produced were subjected to a combustion test in a pellet stove to analyze the emissions associated to each sample. The results show that not all residues pelletize satisfactorily, which is due to the different conditions of the precursors. Adding pyrenean oak residues to the olive pomace samples guarantees a more effective compression of the pellet, improving its manipulation and transport, without significantly modifying its thermal properties. Concerning the pellet combustion, emissions are slightly worse with olive pomace pellet, concluding that it is not recommendable to use blends with more than 50% of this product.

Nutrient content and in vitro digestibility of Turkish grape pomaces

During harvest of grapes for wine production in Turkey, a total of 28 fresh grape pomace samples from white and red wine grape varieties were collected from wine production facilities. Samples were classified by grape color and the pomace from red grapes was separated manually into stalk, skin plus pulp and seed fractions. Nutrient contents were determined for total samples and for fractions. Assays included dry matter (DM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF) and ash. To estimate ruminal digestion, in vitro disappearance of DM and NDF were determined using ruminal fluid collected at a local slaughterhouse. Color of grape altered (P<0.05) DM, CP, NDF and ADF content of the grape pomace. Although in vitro disappearance of DM and NDF at 48h was similar for pomace from both white and red grapes, DM disappearance was higher at short incubation times for pomace from red grapes. Nutrient content generally differed among the fractions of pomace assayed, and in vitro disappearance of DM at 48h was higher for skin plus pulp and for seed than for the stalk fraction of the pomace. Fresh grape pomace, particularly pomace from red grapes rich in skin and seed, should be a suitable feed for ruminants and to nonruminants with extensive cecal fermentation.

Influence of pectinase treatment on fruit spirits from apple mash, juice and pomace

The current investigation was conducted to determine the influence of pectinase treatment on fruit spirits produced from apple mash, juice, and pomace. Crispin apples were processed into apple mash, juice, and pomace in our pilot-plant, and fermented with a commercial Red Star wine yeast (Sachharomyces cerevisiae Davis 904). After fermentation, the samples of fermented apple mash, juice, and pomace were distilled, and the distillates were analyzed by HPLC with a Bio-Rad Aminex HPX 87H column and a refractive index detector. Methanol, ethanol, n-propanol, iso-butanol, and iso-amyl alcohol were identified as the major alcohols in all the apple spirits. Student's t-test results indicate that there are significant differences between the methanol concentrations of pectinase treated and non-pectinase treated apple spirits. Duncan's multiple range tests show significant differences in the concentrations of methanol of the fruit spirits made from apple mash, juice, and pomace. Apple pomace yielded significantly higher methanol concentrations than apple mash and juice. Pectinase treatment had little effect on the concentrations of n-propanol, iso-butanol, and iso-amyl alcohol. It is concluded that fruit spirits made from the pectinase treated mash, juice, and pomace of Crispin apples had methanol concentrations significantly above the United States FDA guidance of 0.35% by volume or 280mg/100mL of fruit brandy containing 40% ethanol.

Prebiotic potential of a refined product containing pectic oligosaccharides

Apple pomace samples were subjected to Simultaneous Saccharification and Fermentation (SSF) to yield a medium containing mainly lactic acid and oligosaccharides. After lactic acid removal by ion exchange, the SSF medium was refined by a two-step (diafiltration-concentration) membrane treatment. Limited losses of glucooligosaccharides, galactooligosaccharides, xylooligosaccharides and arabinooligosaccharides were noticed in permeates, whereas the concentrate from the second stage showed low concentrations of lactic acid, arabinose and NaCl, which were extensively removed in the refining process. About 60% other the non-saccharide compounds present in the solution fed to membranes were removed in permeates, whereas oligogalacturonides were quantitatively recovered in the final concentrate. The refined product was assayed for its prebiotic potential by means of in vitro fermentability assays performed with individual microbial strains or human fecal inocula. In this latter case, the dynamics of microbial populations was assessed by Fluorescent In Situ Hybridization (FISH). The experimental results proved the prebiotic effects caused by the refined product obtained in this work, which included the promotion of beneficial bacterial growth and the increase of short chain fatty acids (SCFA) concentrations.

Fast determination of principal volatile compounds in distilled spirits

A fast determination of principal volatile compounds (acetaldehyde, ethyl acetate, acetal, methanol, butan-2-ol, butan-1-ol and higher alcohols) by direct inject of the spirit drink has been developed. At a total analysis time of 23 min were quantified others 23 additional volatile compounds like ethyl esters, acetates higher alcohols, 1-hexanol, carbonyl compounds and others, responsible for the quality evaluation of the distillate. These compounds are very important for analysis of fermentation conditions, storage techniques and the quality control of the distillation process. The proposed method has been validated with r 2 values from 0.9988 to 0.9999 with limits of detection varied between 0.003 mg/L for isobutyraldehyde and 0.076 mg/L for diethyl succinate and acceptable reproducibility. The developed method was successfully applied to different samples of grape pomace protected by Specific Denomination “Orujo de Galicia”.

Determination of simple sugars, malic acid and total phenolic compounds in apple pomace by infrared spectroscopy and PLSR

SummaryThe aim of this work was to develop a fast, versatile, inexpensive and environmentally safe analytical method to quantify simple sugars, malic acid and total phenolic compounds in apple pomace, considering its potential use as a raw material with value instead of as an industrial waste. Diffuse reflectance infrared spectroscopy (DRIFTS) measurements of twenty‐six samples of apple pomace were analysed by partial least squares regression (PLSR), using several signal pre‐processing methods. Multivariate models developed with four to five latent variables (LVs) and based in the MIR (mid‐infrared) region had good prediction for the determination of sucrose, fructose, malic acid and total phenolic compounds, with average errors between 3.9% and 6.6%. By contrast, glucose was better determined by models developed in the NIR (near‐infrared) region and using six LVs, yielding an average error lower than 7.4%. These results confirmed the feasibility of the multivariate spectroscopic approach as an alternative for expensive and time‐consuming conventional chemical methods.

Drying characteristics and quality change of unutilized-protein rich-tomato pomace with and without osmotic pre-treatment

Commercial processing of tomato utilizes only juice, while the wet pomace is considered merely as a waste product. However, tomato pomace represents a very significant source of lycopene, lipids, ascorbic acid, fibers, and proteins. High protein and lysine content tomato seeds, a major part of the pomace waste, are an unexplored source of non-conventional oil which possesses properties similar to conventional oils. However, tomato pomace is highly perishable in its fresh state because it contains about 95% moisture. Therefore, it is just dumped and allowed to decay, causing a serious environmental problem and a waste of resources. Tomato pomace must be dried immediately to reduce moisture before microbial spoilage and mold develop. The aim of this work was to investigate the effect of temperature and osmotic dehydration on air drying kinetics of tomato pomace, and assess the ability of selected drying models to quantify the moisture removal behaviour in tomato pomace over the range of temperatures normally encountered in industrial dryers for the purpose of simulation, scaling up of the process and saving energy. In general, increasing drying-air temperature increases drying potential and consequently decreases process time. Osmotic pre-treatment was found to be effective for enhancing drying rate and reducing drying time by approximately 30%. The effective moisture diffusivity varied from 0.3 × 10 −9 to 2.6 × 10 −9 m 2/s in the temperature range (40–80 °C). The effective moisture diffusivities of NaCl-treated samples dried at 60 °C was 1.1 × 10 −7 m 2/s (80 times higher than untreated samples). The temperature dependence of the effective diffusivity was described by the Arrhenius relationship with an activation energy of 52.1 kJ/mol. Colour analysis showed that the values of the colour parameters ( L*, a*, b* and h*) increased with drying temperature made the colour of the pomace samples brighter, shifting it towards yellow and red. Pre-treatment with NaCl had a small effect on colour parameter values.

Determination of Ochratoxin A in Grapes, Dried Vine Fruits, and Winery Byproducts by High-Performance Liquid Chromatography with Fluorometric Detection (HPLC−FLD) and Immunoaffinity Cleanup

A liquid chromatographic method for the determination of ochratoxin A in grapes, dried vine fruits, and winery byproducts was developed. A mixture of either acetonitrile/water or acetonitrile/water/methanol was used as an extraction solvent mixture. After immunoaffinity column cleanup, the final extract was analyzed by high-performance liquid chromatography (HPLC) with a fluorometric detector (FLD). Mean recoveries from grapes, grape pomace, and lees samples spiked in the range of 1-200 microg/kg were 78, 86, and 88%, respectively, with a detection limit of 0.1 microg/kg and within-laboratory repeatability ranging from 6 to 15%. Tested on naturally contaminated samples of grapes, grape pomace, and sultanas, the method showed better performances as compared to two other methods also based on immunoaffinity cleanup and HPLC/FLD determination. Ochratoxin A was detected in samples of grape pomace (levels ranging from 34.2 to 456.8 microg/kg) and lees (levels ranging from 48.3 to 602.5 microg/kg) derived from the wine making of red grapes of 2004 and 2005 vintages in southern Italy. After distillation of contaminated grape pomace in a pilot-scale equipment to produce grappa, the toxin remained unchanged in the exhausted pomace and was not detected in any of the distilled fractions (detection limit of 0.02 microg/L).

Polycyclic Aromatic Hydrocarbons in Spanish Olive Oils: Relationship between Benzo(a)pyrene and Total Polycyclic Aromatic Hydrocarbon Content

Samples of Spanish virgin olive oils (VOOs) from different categories, origins, varieties, and commercial brands were analyzed by HPLC with a programmable fluorescence detector to determine the content of nine heavy polycyclic aromatic hydrocarbons (PAHs): benzo(a)anthracene, chrysene, benzo(e)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perilene, and indeno(1,2,3-c,d)pyrene. Samples of olive pomace and crude olive pomace oils were also investigated. Benzo(a)pyrene concentrations were below the allowed limit in the European Union (2 microg/kg) in 97% of the VOO samples. Only those samples coming from contaminated olive fruits or obtained in oil mills with highly polluted environments exceeded this value. High correlation coefficients (<0.99) were obtained between the contents of benzo(a)pyrene and the sum of the nine PAHs for all of the analyzed categories, suggesting that benzo(a)pyrene could be used as a marker of the content of these nine PAHs in olive oils.

Composição do conteúdo de ácidos fenólicos no bagaço de maçã (Malus sp)

The present work aimed the study of phenolic acids composition in apple pomace of Gala and Fuji cultivars. Phenolic acids were fractionated in phenolic acids, esterified and insoluble and analyzed by gas chromatography–mass spectrometry (GC-MS). Sixteen phenolic acids were identified in apple pomace samples. Total phenolic acids in apple pomace from Gala and Fuji cultivars were, in dry weight, 93.94 mg/ g and 68.38 mg/g, respectively. Content of free phenolic acids in apple pomace from Gala cultivar was 29.11 mg/g and the following acids were identified: salicylic, protocatequinic, quinic, p-coumaric, gallic, propylgallate and synapic. Content of free phenolic acids in apple pomace from Fuji cultivar was 16.03 mg/g and the following acids were identified: salicylic, protocatequinic, gallic, ferulic and sinapic. Salicylic was the predominant free phenolic acids found in both cultivars, consisting of 91.67% and 63.57% of the free phenolic acids in Gala and Fuji cultivars, respectively. Chlorogenic acid (1.147 mg/g) was found only in apple pomace from Fuji cultivar. Content of esterified phenolic acids in apple pomace from Gala and Fuji cultivars were 53.75 mg/g and 48.29 mg/g, respectively. It was verified that the predominant esterified phenolic acid in pomace from apple Gala is derived from salicylic acid (52.76 mg/g). Acids derived from gallic acid (0.175 mg/g), propylgallate acid (0.198 mg/g), ferulic acid (0.159 mg/g) and sinapic acid (0.140 mg/g) were also found in Gala cultivar. Regarding to pomace from cultivar Fuji, the main esterified phenolic acid found is also derived from salicylic acid (47.42 mg/g) followed by gallic acid (0.270 mg/g), benzoic acid (0.194 mg/g) and sinapic acid (0.115 mg/g). Content of insoluble phenolic acids in apple pomace from Gala and Fugi cultivars were, in dry weight, 11.08 mg/g and 4.05 mg/g, respectively. Insoluble phenolic acids derived from salicylic acid were found in higher concentrations in apple pomace from both cultivars.

Quantitation of polyphenolic content and determination of antilisterial activities of grapes and vinification byproducts

Four grape varieties (two red and two white) –cultivated in the Greek islands– were studied in respect to their total polyphenolic content (TPC) and quantization of their main polyphenols. More specifically, berries, seeds, stems and pomace samples were examined, indicating that seeds contain high concentration of flavan-3-ols and respective derivatives, while pomace and stems contain considerable amounts of flavonoids. stilbenes and phenolic acids. In particular, stems were found to possess high trans-resveratrol and ε-viniferin content. Subsequently, the in vitro antilisterial activities of these extracts were evaluated.

New biosorbent materials for heavy metal removal: Product development guided by active site characterization

Olive pomace wastes were used as precursors for the development of new biosorbents for heavy metals. Thermal and/or chemical treatments were addressed in terms of their effects on functional group properties and copper removal. Product development was guided by experimental characterization (potentiometric titrations, IR spectra, copper biosorption, total surface area) and theoretical modeling of acid–base properties. Olive pomace was characterized by negative charge due to dissociation of two weakly acidic sites (carboxylic and phenolic). After thermal treatment, a char-like material was obtained, characterized by basic sites with positive charge in the acidic pH range. Copper biosorption properties of this material were improved with respect to olive pomace due to the binding ability of pyrone-like sites. Both native and carbonized olive pomace samples were chemically treated by HNO 3. Experimental tests were performed according to factorial designs and analysis of variance was used to evaluate significant effects on copper removal of both oxidant concentration and temperature. Chemical treatment by HNO 3 of carbonized material developed negatively charged groups in the acidic pH range (carboxylic groups), but presented a decreased copper removal. Chemical treatment by HNO 3 of olive pomace without carbonization gave biosorbents with acid–base properties similar to those of native olive pomace, but with a significant increase of copper biosorption. Specific carboxylic–copper interactions indicated by IR spectra and increased surface area due to chemical treatment were simultaneously responsible for such improvement.

Polyphenol-enriched fractions from Sicilian grape pomace: HPLC–DAD analysis and antioxidant activity

On the basis of a preliminary screening of seven different samples of Sicilian grape pomace, the ‘Nerello Mascalese’ sample NM2 was selected for an ethanol preparative extraction. The defatted NM2 EtOH extract was subjected to DPPH and GAE assays, showing good radical scavenging activity (SC 50 = 9.9 μg/mL) and a GAE value of 397.7 mg/g extract. HPLC–DAD analysis of NM2 extract allowed a quantitative determination of the main anthocyanins (AN) and flavonols/flavonol glycosides (FL/FG). Aliquots of the NM2 extract were subjected to three different fractionation protocols (FP1, FP2 and FP3). The fractions were examined by DPPH and GAE assays, and subjected to HPLC–DAD analysis for the quantitative determination of the main AN and FL/FG. FP3 allowed obtaining a polyphenol-enriched fraction with SC 50 = 14.8 μg/mL and GAE = 184.1 mg/g of fraction, accounting for only 1.3% in weight of the EtOH extract. Some considerations about the relationship between antioxidant activity and AN/FL/FG HPLC–DAD profiles are also reported.

Methanol content of grappa made from New York grape pomace

This research was undertaken to determine the methanol content of grappa made from the sweet pomace of five grape varieties grown in the Finger Lakes wine region of New York state. The mean concentrations of methanol ( N = 3) in the distilled spirits made from the pomace samples of Niagara, Cayuga White, Gewurztraminer, Chardonnay, and Riesling grapes were estimated to be 44, 38, 138, 55, and 112 mg/100 mL of 40% alcohol, respectively. The results of this work indicate that the sweet pomace of five New York grape varieties could be used in the production of grappa with a methanol level within the United States legal limit of 280 mg/100 mL of 40% alcohol.

L-Lactic acid production from apple pomace by sequential hydrolysis and fermentation

The potential of apple pomace (a solid waste from cider and apple juice making factories) as a source of sugars and other compounds for fermentation was evaluated. The effect of the cellulase-to-solid ratio (CSR) and the liquor-to-solid ratio (LSR) on the kinetics of glucose and total monosaccharide generation was studied. Mathematical models suitable for reproducing and predicting the hydrolyzate composition were developed. When samples of apple pomace were subjected to enzymatic hydrolysis, the glucose and fructose present in the raw material as free monosaccharides were extracted at the beginning of the process. Using low cellulase and cellobiase charges (8.5 FPU/g-solid and 8.5 IU/g-solid, respectively), 79% of total glucan was saccharified after 12 h, leading to solutions containing up to 43.8 g monosaccharides/L (glucose, 22.8 g/L; fructose, 14.8 g/L; xylose + mannose + galactose, 2.5 g/L; arabinose + rhamnose, 2.8 g/L). These results correspond to a monosaccharide/cellulase ratio of 0.06 g/FPU and to a volumetric productivity of 3.65 g of monosaccharides/L h. Liquors obtained under these conditions were used for fermentative lactic acid production with Lactobacillus rhamnosus CECT-288, leading to media containing up to 32.5 g/L of l-lactic acid after 6 h (volumetric productivity = 5.41 g/L h, product yield = 0.88 g/g).

Supercritical carbon dioxide extraction of carotenoids, tocopherols and sitosterols from industrial tomato by-products

In this work the supercritical carbon dioxide extraction of biologically active, high valued compounds such as carotenoids (lycopene, β-carotene), tocopherols, fatty acids and sitosterols from industrial tomato waste was investigated. The differences of two samples of different sources and the effect of air-dried and deep-frozen storages were also reported. The effects of extraction parameters (pressure and temperature) on the extraction yields and the compositions of the products were determined with statistical analysis. Supercritical fluid extraction was compared to conventional extraction processes of tomato pomace samples. The extracts were analysed by gas chromatography, by high-performance liquid chromatography and by TLC-densitometry. The extraction yields and the amounts of lycopene, tocopherols and sitosterols depend on the experimental conditions. The product obtained by supercritical CO 2 extraction at 460 bar and 80 °C contained the highest concentration of carotenoids with 90.1% of lycopene, while products rich in tocopherols and phytosterol were obtained above 300 bar and 40 °C.

Chemical characterization of tomato pomace

AbstractTomato‐processing by‐product, also known as tomato pomace, consists of peel and seeds and represents around 4% of the fruit weight. If these wastes remain unused, they not only add to the disposal problem but also aggravate environmental pollution. The aim of this paper is to evaluate the chemical composition of tomato pomace collected at different steps during industrial processing in order to assess the quality of this by‐product. Twenty‐one tomato pomace samples were considered for analysis. Samples corresponded to different steps during tomato processing for paste: seven after pulper, five after finisher, six before turbopress and three after turbopress. Samples were analyzed for moisture content, total and soluble sugars, protein, fat, soluble and total fiber, as well as mineral content. From the results obtained we can conclude that tomato pomace composition (in dry weight basis) is as follows: 59.03% fiber, 25.73% total sugars, 19.27% protein, 7.55% pectins, 5.85% total fat and 3.92% minerals. Copyright © 2006 Society of Chemical Industry

Ultrasound-assisted extraction of xyloglucan from apple pomace

Ultrasound-assisted extraction was evaluated as a simpler and more effective alternative to conventional extraction method for the isolation of xyloglucan from apple pomace. The apple pomace samples were extracted under indirect sonication in an ultrasound cleaning bath. The ultrasound extraction was compared with the conventional method, on the productions of xyloglucan. It was found that the ultrasound-assisted extraction of xyloglucan was about three times faster than the traditional extraction method. Response surface methodology was employed to study the effect of liquid:solid ratio, KOH concentration and ultrasound-assisted extraction time on the yield of xyloglucan from apple pomace. Regression analysis was performed on the data obtained. The most relevant variable was the quadratic of liquid:solid ratio. The coefficient determination ( R 2) was good for the second-order model. The optimum combination was determined as a liquid:solid ratio of 34.4:1 (v/w), a KOH concentration of 3.3 M and an ultrasound-assisted extraction time of 2.5 h.