Pomace Samples Research Articles

Drying of tomato pomace in daylight simulated photovoltaic‐assisted drying system: Effects of daylight intensity and application mode

AbstractIt was aimed to dry a by‐product of tomato paste production (tomato pomace) by minimizing the losses valuable components and reducing energy consumption. In this concept, a daylight simulated photovoltaic‐assisted dryer (DPVD) applying the daylight in different modes and intensities during drying was custom‐designed. The effects of daylight applications on the change of some quality characteristics of tomato pomace and system performance characteristics were investigated, and the optimum drying condition was determined. The process conditions included the combination of three different daylight application modes (UV‐blocked daylight via solar tube‐DLST, DLST + LED, and LED) and three different daylight intensities (2,500, 7,500, and 10,000 lux). The drying was applied for 240 min at constant air temperature (60°C) with an air velocity of 2 m/s. The moisture content and the water activity values of dried tomato pomace were 8.86 ± 2.00% and 0.57 ± 0.10%, respectively. The lycopene and β‐carotene losses after drying were determined as 68.36 ± 4.32% and 65.66 ± 4.33%, respectively. The energy and exergy efficiencies of the system were in the range of 19.56%–35.73% and 5.10%–17.05%, respectively. The optimum condition meeting the criteria of superior quality and high‐performance characteristics was obtained by applying DLST at 7,500 lux (desirability 0.728). In the performance improvement studies, it has been concluded that all the energy required for the process could have been fulfilled as 100% from solar energy with the support of photovoltaic panels. In other words, it was demonstrated that the developed DPVD system could be used to dry the tomato pomace not only in terms of providing high food quality and safety, but also in terms of having high energy efficiency.Practical applicationsExposure to the daylight is important to dry some foods. Especially in north countries, products are dried in artificial dryers, but it requires high energy consumption. In this study, the daylight transfer system was integrated into the artificial dryer for the purpose of using daylight effect in addition to the photovoltaic (PV) assistance for using solar energy. During periods when the solar thermal effect is not intense or in countries where the sun effect is limited, it will be possible to dry food products with the daylight effects via using the DPVD system in suitable microbiological conditions.In this study, tomato pomace samples, which are the byproduct of tomato paste production, could be dried in daylight simulated PV‐assisted drying system in high quality and with low energy consumption. It is concluded that it can be possible to obtain valuable components from a byproduct having no economical value.

Grape pomace treatment methods and their effects on storage

Introduction. Grape pomace is the most important by-product of winemaking that can be used as an additional raw material. There is a need for an optimal storage technology so that pomace can be further processed to obtain new types of products. We aimed to study the effect of grape pomace treatment on its microflora.
 Study objects and methods. We identified and quantified microflora on the fresh and one-month-stored pomace samples from white and red grape varieties. The samples were exposed to conventional drying at 60–65°C, infrared drying at 60–65°C, as well as sulfitation with sulfur dioxide and sodium metabisulfite.
 Results and discussion. The pomace microflora can be considered a microbial community. Almost all the samples stored for one month in an open area contained Saccharomyces cerevisiae yeasts, higher concentrations of filmy yeasts of the Candida, Pichia, Hansenula, Hanseniaspora/Kloeckera, and Torulaspora genera, as well as conidia of Mucor, Aspergillus niger, and Penicillium molds. Prevalent bacteria included acetic acid (mainly Acetobacter aceti) and lactic acid (Lactobacillus plantarum, Pediococcus, Leuconostoc) bacteria. These microorganisms significantly changed concentrations of volatile and non-volatile components, decreasing total polysaccharides, phenolic compounds, and anthocyanins 1.7–1.9, 3.7–4.0, and 4.0–4.5 times, respectively. The contents of micromycetes and bacteria in the one-month-stored samples were significantly higher than in the fresh pomace. Predrying and sulfitation decreased bacterial contamination, but to a lesser extent compared to micromycetes.
 Conclusion. Long-term storage spoiled pomace, leading to significant changes in its chemical composition. Sulfitation reduced microorganism growth during storage, but did not provide long-term preservation (over a month), while pre-drying at 60–65°C promoted longer storage.

Antioxidants Characterization of the Fruit, Juice, and Pomace of Sweet Rowanberry (Sorbus aucuparia L.) Cultivated in Estonia.

This study aimed to identify promising candidates of rowanberry cultivars for a wider cultivation and utilization. Antioxidant properties and phenolic content were evaluated for fruit, juice, and pomace samples of 16 different sweet rowanberry cultivars (cvs) and wild rowanberry (S. aucuparia L.), while the antioxidant potential was assessed using three different methods, based on the capacity to scavenge ABTS●+ and DPPH● and measure the oxygen radical absorbance capacity (ORAC). In general, the radical scavenging capacity was higher for hybrid cultivars, e.g., for cvs Likernaja, Burka, Granatnaja, and Rubinovaja in all assays. The highest value in the ABTS●+ assay was determined for the fruit sample Likernaja, and in DPPH● assay in the pomace sample of cv. Likernaja, at 527.55 and 1068.28 µM TE/g dw, respectively. The highest ORAC value was found in the fruit sample of Burka (456.53 µM TE/g dw). Among the Nevezhino rowans, the highest radical scavenging values of all fractions were determined in cv. Solnechnaja. Regarding the total phenolic content (TPC), higher values were obtained in the whole fruits than in separated fractions, juice, and pomace. The tested hybrids had higher TPC values, either in fruit and pomace or in juice extracts, than those in the other analyzed S. aucuparia L. cultivars. While the fruit and juice samples showed higher anthocyanin (ACY) values, the pomace samples had higher hydroxycinnamic acid (HCA) contents on average. The results revealed that the different fractions of selected rowanberry cultivars can be a promising source of antioxidants and polyphenols for further potential applications. It is envisaged that the results of this study will serve in valorizing sweet rowanberry cultivars as value-added functional ingredients for food and non-food applications.

Correlations between Total Antioxidant Capacity, Polyphenol and Fatty Acid Content of Native Grape Seed and Pomace of Four Different Grape Varieties in Hungary.

Grape pomace is a valuable source of various bioactive compounds such as plant-derived polyphenols and polyunsaturated fatty acids (PUFAs). The commercial demand of grape skin and seed powders as nutraceuticals is still growing. However, no distinction is currently made between unfermented native grape seed and grape seed pomace powders regarding their antioxidant activities. Our aim was to find the relationship between the polyphenol and fatty acid content as well as the antioxidant capacity of native and fermented grape seeds of four different grape varieties harvested in the Villány wine region. According to our results, none of the three investigated polyphenols (resveratrol, rutin, quercetin) could be detected in native grape seed samples in correlation with their significantly lower total antioxidant capacities compared to fermented seed samples. Pinot Noir (PN) grape seed pomace samples with the highest resveratrol and oil content showed significantly higher total antioxidant capacity than Cabernet Sauvignon (CS), Syrah (S) and Blue Portugal (BP) samples. Based on the statistical analysis, positive correlation was found between the fatty acid content and the resveratrol concentration in the pomace samples of different grape varieties. In contrast, rutin concentrations were negatively proportional to the fatty acid content of the fermented samples. No significant correlation was found considering the quercetin content of the samples. According to our findings, grape pomace seems a more promising source in the production of nutraceuticals, since it contains polyphenols in higher concentration and exerts significantly higher antioxidant activity than native grape seeds.

Effect of Lactobacillus plantarum-fermented mulberry pomace on antioxidant properties and fecal microbial community

Rich in phenolic compounds and dietary fibers, mulberry pomace is a potential material for gut health. This study investigated the effect of the probiotic Lactobacillus plantarum on mulberry pomace. The antioxidant activity as well as the changes of fecal microbiota and short-chain fatty acids (SCFAs) were determined using chemical models, quantitative polymerase chain reaction (qPCR) and gas chromatography, respectively. Furthermore, the phenolic compounds were characterized by UPLC-MS. The results showed that the antioxidant activity was significantly improved in fermented mulberry pomace (FMP) samples. The fecal microbiota community was modulated by FMP through improving beneficial bacteria (Lactobacillus, Bifidobacterium, Ruminococcus, butyrate-producing bacteria and Akkermansia) and inhibiting pathogenic bacteria (Escherichia coli and Enterococcus). Moreover, FMP showed an increase in the production of SCFAs and lactic acid. The study identified that the corresponding glycosides of cyanidin and quercetin were released during Lactobacillus plantarum fermentation. A total of eighteen phenolic compounds were detected in samples and three compounds (p-hydroxybenzoic acid, catechin and gallocatechin) were only detected in FMP samples. The changes in phenolic compounds might explain the gut-improving functions. This study provided a suggestion that Lactobacillus plantarum fermentation was a potential way to utilize mulberry pomaces as a functional food.

Phytochemical Characterization and Antiplatelet Activity of Mexican Red Wines and Their By-products

Red wines and their grape pomaces are important sources of phenolic compounds. Inhibition of plateletaggregation is one of the mechanisms proposed for cardioprotective effect of phenolic compounds fromwine and grape pomace; however, phenolic content is affected by region, variety and winemaking process.In the present study, antiplatelet effect of red wines and grape pomaces was related to its phenolic content(determined by spectrophotometric techniques) and profile (determined using HPLC-MS/MS). in vitroAnti-platelet aggregation was determined using human platelets. Results showed that Zinfandel wine andCabernet Sauvignon grape pomace presented the highest phenolic content. Phenolic profiles presenteddifferences in the presence of flavonoids and oligomeric tannins. Results from platelet aggregationshowed that Merlot and Petit Verdot wines and Petit Verdot grape pomace sample presented the highestantiaggregant effect. These results indicate that antiplatelet effect could be related to phenolic profile thanphenolic content in wines and grape pomaces. Cardioprotective effect of red wines and grape pomacecould be related to specific compounds such as monomeric and polymeric flavan-3-ols.

Energy Utilization of Torrefied Residue from Wine Production.

A significant amount of waste is generated in the food industry, which is both an environmental and an economic problem. The recycling of this waste has become an important area of research. The processing of grapes produces 20–30% of the waste in the form of grape pomace and stalks. This article assesses the fuel values of these materials before and after torrefaction. The input materials were grape pomace samples from the varieties Riesling (Vitis vinifera “Welschriesling”) and Cabernet Sauvignon (Vitis vinifera “Cabernet Sauvignon”) from the South Moravia region and stalks from the variety Welschriesling. The torrefaction process was performed using a LECO TGA 701 thermogravimetric analyzer under nitrogen atmosphere at set temperatures of 225 °C, 250 °C, and 275 °C. The residence time was 30 min. Elemental analysis, calorific value, and gross calorific value were determined for all samples. The analyses show a positive effect of torrefaction on fuel properties in the samples. Between temperatures 250 °C and 275 °C, the carbon content increased by 4.29 wt.%, and the calorific value increased with the increase in temperature reaching a value of 25.84 MJ·kg−1 at a peak temperature of 275 °C in the sample grape pomace from blue grapevine.

Comparative analysis of antioxidant activity, toxicity, and mineral composition of kernel and pomace of apricot (Prunus armeniaca L.) grown in Balochistan, Pakistan.

The present study aims to investigate some physical attributes, total phenolics content, total flavonoids content, mineral composition, bioluminescence toxicity assay and antioxidant activity in terms of DPPH, HPS, TAC and FRAP assays in the kernel and pomace samples of six apricot cultivars grown in Balochistan, Pakistan. TFC and TPC determined by the AlCl3 and Folin-Ciocalteu assays in apricot kernel extracts of six cultivars varied from 1797.5 (Chagali) to 4778.9 (Badoghur) mg QUE/100 g DW and from 1750.0 (Chagali) to 5005.8 (Badoghur) mg GAE/100 g DW. Apricot kernels exhibited higher antioxidant activity than pomace; antioxidant activity in terms of IC50 in kernels ranged from 24.88 to 98.61 μg/ml for DPPH, 334.84 to 516.63 μg/ml for HPS, from 22.02 to 110.80 μg/ml for TAC and from 96.27 to 163.35 μg/ml for FRAP. The apricot kernels showed higher TPC, TFC, bioluminescence toxicity to V. logei and antioxidant activity than the pomace. The correlation analysis demonstrated substantial contributions of polyphenols and flavonoids to antioxidant assays. The sample type was the leading factor affecting the amounts of K, Na, Ca, Fe, and Mn in the tested samples; mineral contents were higher in pomace than kernels. The highest inhibition to V. logei was found in the kernels of Badoghur (IC50 = 1.61 mg/ml). The PCA analysis showed significant contributions of phenolic and flavonoid contents towards antioxidant bioluminescence toxicity assays. Our results suggest Badoghur, Shakarpara and Sardai kernels are rich sources of secondary metabolites and possess remarkable antioxidant and antiluminescence activity and can make a significant contribution to the treatment and prevention of chronic health problems.

Near Infrared (NIR) Spectroscopy as a Tool to Assess Blends Composition and Discriminate Antioxidant Activity of Olive Pomace Cultivars

Currently, monovarietal olive oils are increasingly present on the market and generate large amounts of monovarietal olive pomaces. Considering the high production of this by-product and its bioactive content, it is essential to explore green, reliable, easy-to-go, and low-cost techniques that allow their easy analysis and discrimination. In this sense, the goal of this work was to use near infrared (NIR) spectroscopy to assess the composition and to estimate the antioxidant activity of olive pomace. A total of 53 samples including four monovarietal cultivars (Arbequina, Arbosana, Koroneiki and Oliana) and 49 different blends were used for this study. The antioxidant activity was evaluated through ferric reducing antioxidant power (FRAP), total phenolic content (TPC) and the 2,2-diphenyl-1-picrylhydazyl radical (DPPH·) scavenging ability. The NIR spectra of olive samples were calibrated against these chemical parameters and the composition of each sample using PLS modelling. The discrimination of the olive pomace samples with a high amount of bioactive compounds in terms of TPC, FRAP and DPPH· scavenging ability was performed through PLSDA modelling. The PLS models results regarding olive pomace samples composition yielded coefficients of determination of prediction (R2P) and range error ratio (RER) values higher than 0.9 and 12, respectively, while the PLS models results for the determination of the antioxidant activity yielded unsatisfactory results. For the PLSDA models, the percentage of correct predictions obtained using the validation set was 82, 90, 61% for DPPH· scavenging ability, TPC and FRAP, respectively. Globally, the obtained results attest that NIR spectroscopy is an interesting green analytical technique for the valorization of olive industry by-products, namely olive pomace, through the determination of their composition and the discrimination between samples with a higher amount of bioactive compounds.

Effect of particle size distribution, drying and milling technique on explosibility behavior of olive pomace waste

The Mediterranean area is responsible for about 98% of the olive oil worldwide production, with 900 million olive trees occupying 10 million hectares. However, the processing of 100 kg of olives leads to the production of 40 kg of wastes, mainly constituted by olive pomace, which is potentially recoverable as energetic or material source. In general, in the past 20 years, the exploitation of olive pomace has increased, but along with it, the need for further information about its chemical-physical characterization and the related hazard in industry. Thus, a risk analysis assessment was conducted. When pelletized or in chunks, olive pomace does not pose any greater hazard than a pile of woody material, but when pulverized, it might become dangerous. Two parallel series of experiments were carried out at Dalhousie University (Lab 1) and at Polytechnic of Turin (Lab 2) using the same olive pomace sample, according to slightly different experimental procedures. Olive pomace dust explosibility and flammability parameters were measured: minimum ignition energy (MIE), minimum ignition temperature (MIT), maximum pressure rise rate ((dP/dt)max and KSt), maximum pressure (Pmax), and minimum explosible concentration (MEC). Moreover, the chemical and physical characterization of olive pomace was carried out: moisture content, particle size analysis, Scanning Electronic Microscope (SEM) investigation, thermo-gravimetric analysis (TGA), solid-state Nuclear Magnetic Resonance (NMR), mass spectrometry, calorific value, and bulk density estimation. Different thermal behaviors were observed according to the sieving/grinding pre-treatment. As concern flammability tests, samples seemed not to be sensitive to electric arc ignition (a value of MIE could not be measured), while coarser samples demonstrated higher ignition sensitivity to hot environment sources (MIT furnace) than finer ones. On the other hand, explosion violence parameters were enhanced by decreasing the particle size, while peak pressures were significantly influenced by the heat of combustion and the moisture content. Finally, a new test was developed to quantify the propensity of the raw material to produce fines by abrasion. It is defined “Abrasion by Rolling Test” (ART). The properties of the fines produced were measured as well.

Supercritical CO2 Extraction of Phytocompounds from Olive Pomace Subjected to Different Drying Methods.

Olive pomace is a semisolid by-product of olive oil production and represents a valuable source of functional phytocompounds. The valorization of agro-food chain by-products represents a key factor in reducing production costs, providing benefits related to their reuse. On this ground, we herein investigate extraction methods with supercritical carbon dioxide (SC-CO2) of functional phytocompounds from olive pomace samples subjected to two different drying methods, i.e., freeze drying and hot-air drying. Olive pomace was produced using the two most common industrial olive oil production processes, one based on the two-phase (2P) decanter and one based on the three-phase (3P) decanter. Our results show that freeze drying more efficiently preserves phytocompounds such as α-tocopherol, carotenoids, chlorophylls, and polyphenols, whereas hot-air drying does not compromise the β-sitosterol content and the extraction of squalene is not dependent on the drying method used. Moreover, higher amounts of α-tocopherol and polyphenols were extracted from 2P olive pomace, while β-sitosterol, chlorophylls, and carotenoids were more concentrated in 3P olive pomace. Finally, tocopherol and pigment/polyphenol fractions exerted antioxidant activity in vitro and in accelerated oxidative conditions. These results highlight the potential of olive pomace to be upcycled by extracting from it, with green methods, functional phytocompounds for reuse in food and pharmaceutical industries.

Drying characteristics of aonla (Emblica officinalis) pomace

The increasing consumption of animal products will give rise to a huge demand of animal feed. Meeting this demand will be a challenge, given the scarcity of natural resources such as land and water. The major waste produced includes the organic waste such as peel, stem, core, seeds and pomace. In case of aonla pomace sample, drying time at 45, 55 and 65 °C was 210, 180 and 165 min respectively. Moisture loss was found to be temperature dependent and slow at lower temperature and took more time as compared to drying at higher temperatures. It can also be observed from these curves that the drying time decreased with increase in drying air temperature.

Effects of superfine grinding on asparagus pomace. Part II: Changes on intestinal function and health

This study aims to evaluate the effects of asparagus pomace with different particle size (~10 μm, ~30 μm, and ~80 μm) on intestinal function and health. One hundred and forty male Kunming mice were divided into fourteen groups and were used for small intestine movement experiment, defecation experiment, and intestinal function and health experiment, respectively. Results showed that, asparagus pomace samples treatment could markedly alleviate the constipation caused by loperamide with improved intestinal propulsion rate, reduced initial time of the first black stool, and increased the total mass of faeces within 6 h (P < 0.05), and finer samples worked better. All asparagus pomace-treated groups could significantly reduce the cecum ammonia concentration, increase the faeces dry weight and moisture content, and lower the β-d-glucosidase and β-d-glucuronidase activities. However, the difference in aforementioned properties between ~10 μm and ~30 μm groups were not significant (P > 0.05), and the respective maximal efficiency were observed when the sample was ranged within the size in ~30 μm, which indicated that a rational granularity can meet its objectives. This paper is expected to provide new insights of pulverization on functional properties of fiber-rich food materials.

Platelet Anti-Aggregant Activity and Bioactive Compounds of Ultrasound-Assisted Extracts from Whole and Seedless Tomato Pomace

Tomato paste production generates a residue known as tomato pomace, which corresponds to peels and seeds separated during tomato processing. Currently, there is an opportunity to use tomato pomace to obtain a functional extract with antithrombotic properties, such as platelet anti-aggregant activity. The aim of this study was to evaluate the yield and inhibitory activity of different extracts of tomato pomace on in vitro platelet aggregation, comparing this activity with commercial cardioprotective products, and quantify bioactive compounds. Aqueous or ethanolic/water (1:1) extracts of whole tomato pomace, seedless tomato pomace, tomato pomace supplemented with seeds (50% and 20%), and only seeds were obtained with different ultrasound-assisted extraction times. The inhibition of platelet aggregation was evaluated using a lumi-aggregometer. The quantification of bioactive compounds was determined by HPLC-MS. From 5 g of each type of tomato pomace sample, 0.023–0.22 g of a dry extract was obtained for the platelet aggregation assay. The time of sonication and extraction solvent had a significant role in platelet anti-aggregant activity of some extracts respect the control. Thus, the most active extracts decreased adenosine diphosphate (ADP)-induced platelet aggregation from 87 ± 6% (control) to values between 26 ± 6% and 34 ± 2% (p < 0.05). Furthermore, different ultrasound-assisted extraction conditions of tomato pomace fractions had varied concentration of flavonoids and nucleosides, and had an effect on extract yield.

Fast pyrolysis as an alternative to the valorization of olive mill wastes

The valorization of organic wastes through fast pyrolysis appears to be a highly promising option for decreasing pollutants and reducing consumption of natural resources. For this purpose, three different olive pomace samples were studied to determine how olive crop location and the extraction process could influence bio-oil product distribution. Olive pomace was selected as the feedstock due to the importance of the olive oil industry in Spain. In this study, the conditions of fast pyrolysis were optimized using lignin as a reference, with the optimum conditions being 500 °C, 20 °C ms-1 as the heating rate and 15 s as the vapour residence time. The olive pomace results determined that not only their chemical composition, but also their fat content had a remarkable effect on product distribution obtained after fast pyrolysis. However, whereas high lignin content enhanced phenol production, cellulose decomposed to carboxylic acids. In addition, due to current global warming, the carbon dioxide (CO2 ) burden of the three samples was calculated using mass spectroscopy. The OPGC sample gave off the lowest amount of greenhouse gases, followed by OPMNE and OPMN. The higher fat content in the sample enhanced carboxylic acid production. The difference in phenol production between OPMN and OPMNE could be attributed to the presence of potassium. From an environmental point of view, the use of olive pomace wastes could reduce CO2 emissions with further research and by developing experimental processes. © 2020 Society of Chemical Industry.

Влияние сорта винограда, места его произрастания и технологии переработки на физико-химические показатели виноградной выжимки

Introduction. Any waste can become a raw material for new products. Therefore, waste should be considered as secondary material resources. Grape pomace is the basic waste of wine industry, and research in its chemical composition may allow for a more effective recycling of food industry waste.&#x0D; Study objects and methods. The research featured sweet and fermented pomace of white and red grapes, namely “Chardonnay”, “Sauvignon Blanc”, “Riesling”, “Pinot Blanc”, “Traminer Pink”, “Viognier”, “Morava” “Pinot Noir”, “Roesler”, “Cabernet Sauvignon”, “Merlot”, “Saperavi”, and “Rebo”. They were obtained in the production of wines at wineries in the Krasnodar region. Mass concentrations of organic acids and cations of alkaline and alkaline-earth elements were determined in extracts by capillary electrophoresis. The data was converted to dry matter. Moisture content was calculated as a percentage of the change in the mass of grape pomace.&#x0D; Results and discussion. The moisture content of sweet pomace varied from 49.33 ± 2.04 to 70.35 ± 0.60%, and in fermented pomace – from 47.49 ± 0.02 to 64.24 ± 0.60%. The varieties were studied for mass concentrations of tartaric, malic, succinic, citric, and lactic acids. Tartaric and malic acids proved to be the most abundant ones. The pomace of Riesling grapes had the greatest amount of tartaric acid (104.47 ± 4.16 g/kg). The “Chardonnay” variety proved rich in malic acid (19.40 ± 2.67 g/kg), while the “Morava” pomace had the biggest amount of citric acid (12.61 ± 1.12) and succinic acid (11.72 ± 1.23). The research also defined concentrations of alkaline and alkaline-earth elements. Their content ranged from 41.04 to 3.29 g/kg. Potassium appeared to be the main cation in the pomace samples. The share of potassium in the total mineralization of pomace was up to 94%. The “Riesling” variety grown near Novorossiysk had the largest amount of potassium (36.46 ± 4.65 g/kg). The samples demonstrated a significant correlation between the content of tartaric acid and potassium.&#x0D; Conclusion. The research revealed a significant variation in the concentration of the organic acids and cations of alkaline and alkalineearth metals, depending on the grape variety, the place of its growth, and processing. The grape pomace samples differed moisture content. It depended on the volume of the liquid fraction, i.e. wort or wine material selected during pressing.

Evaluation of the potential for energy recovery from olive oil industry waste: Thermochemical conversion technologies as fuel improvement methods

The search for new sources of energy is one of the demands of current times. Traditional lignocellulosic biomass sources, used by Man since immemorial times, begin to suffer the effects of overuse, which is why to find new sources is so urgent, especially if those are associated with industrial or agroforestry waste sources. In this context, several options arise, some of which are object of concern, given the large volumes produced, and the environmental impacts associated with them. Olive pomace is one of these cases. Portugal assumes a prominent role in the production of olive oil and is, therefore, also a major producer of waste related with olive oil industry. Energy recovery of olive pomace is something that has been referenced in the bibliography since long ago. However, traditional forms of recovery, such as direct combustion, did not shown to be the best option, given the high content of volatiles of the product, and the problems associated with its storage and transportation. Thermochemical conversion technologies, such as torrefaction or pyrolysis, can play a decisive role here, since in addition to the increment in energy density, allow a very significative volume reduction, facilitating storage and transportation. In the present study, torrefaction and pyrolysis tests were carried out on olive pomace samples at different temperatures, respectively, 300, 400 and 500 °C, followed by the characterization of the obtained materials. There was a significative improvement in the energy content of the materials. The characterization of the Hardgrove Grindability Index (HGI) was also carried out, allowing comparison with coal grindability, and leaving an open door for the possibility of these residues being used as coal substitutes in coal-fueled power plants.

Thermochemical Conversion of Olive Oil Industry Waste: Circular Economy through Energy Recovery

The demand for new sources of energy is one of the main quests for humans. At the same time, there is a growing need to eliminate or recover a set of industrial or agroforestry waste sources. In this context, several options may be of interest, especially given the amounts produced and environmental impacts caused. Olive pomace can be considered one of these options. Portugal, as one of the most prominent producers of olive oil, therefore, also faces the problem of dealing with the waste of the olive oil industry. Olive pomace energy recovery is a subject referenced in many different studies and reports since long ago. However, traditional forms of recovery, such as direct combustion, did not prove to be the best solution, mainly due to its fuel properties and other characteristics, which cause difficulties in its storage and transportation as well. Torrefaction and pyrolysis can contribute to a volume reduction, optimizing storage and transportation. In this preliminary study, were carried out torrefaction and pyrolysis tests on olive pomace samples, processed at 300 °C, 400 °C, and 500 °C, followed by laboratory characterization of the materials. It was verified an improvement in the energy content of the materials, demonstrating that there is potential for the use of these thermochemical conversion technologies for the energy recovery of olive pomace.

Varietal influence on phenolic constituents and nutritive characteristics of pomace obtained from apples grown in western Himalayas

Apple fruit processing is not variety specific in India, which affect the overall quality of the final processed product. The present study was aimed at elucidation of the nutritive value, phenolic content, antioxidant activity and bioactive phenolic constituents of five widely used apple varieties (Royal Delicious, Red Delicious, Golden Delicious, Red Chief and Red Gold) of western Himalayas. The pomace obtained from different varieties was evaluated to assess the fruit quality. Royal Delicious pomace had significantly high (p < 0.05) total dietary fibre content (42.63 ± 1.26%) together with soluble (8.25 ± 0.95%) and insoluble fibre (32.90 ± 0.89%), as compared to other apple varieties. The pomace samples were extracted with 70% aqueous methanol to obtain polyphenol enriched extracts. The results of Folin-Ciocalteau assay showed that hydroalcoholic extract of Royal Delicious pomace exhibit higher phenolic content as compared to other varieties and ranged between 2.19 ± 0.09 and 4.59 ± 0.47mg GAE/g. Royal Delicious pomace also possess higher antioxidant capacity i.e. 3.35 ± 0.10mg/g, 2.71 ± 0.10mg/g and 4.67 ± 0.03mg/g as measured by DPPH, ABTS free radical scavenging assay and FRAP reducing assay, respectively. The higher phenolic content in Royal Delicious pomace was also confirmed by RP-HPLC-DAD analysis. Results of HPLC analysis revealed the presence of phloridzin (487.07 ± 0.04µg/g), quercetin (241.18 ± 0.03µg/g), quercitrin (178.34 ± 0.02µg/g) and quercetin-3-glucoside (195.21 ± 0.05µg/g) as major constituents. Present results indicate that Royal Delicious variety is rich in dietary fibre and phenolic compounds that might be used by the food sector as a source of bioactive health promoting constituents/dietary supplements.

Effect of storage time and use of additives on the quality of grape pomace silages

The objective was to evaluate the chemical and fermentative characteristics of moist grape pomace, treated with additives and ensiled for different times. Samples of wet grape pomace were treated by addition of urea (5 and 10 g/kg of NM) or with enzymatic-bacterial additive (0.2 and 0.4 g/kg NM). Samples were analyzed for pH, ammoniacal nitrogen, buffer capacity, and chemical composition. For CP, an increasing linear behavior was observed with values between 111.3 and 131.6 g/kg of DM, on Days 0 and 96. The NFC and pH had the lowest values shortly after silo closing, indicating intensification of fermentation. The addition of urea promoted an increase in CP contents, reduction in TCHO and NFC contents, and elevation of IVDMD and N-NH3 contents. Wet grape pomace exhibits favorable characteristics for feeding ruminants, with silage being a good alternative for its storage. Practical applications Grape pomace is a fibrous food with satisfactory quantities of residual sugars, it meets the desirable characteristics for conservation in the form of silage for later use in animal feed, mainly ruminant herbivores. The silages showed good quality fermentative and chemicals as an increasing linear behavior of crude protein. Wet grape residue exhibits favorable characteristics for feeding ruminants, with silage being a good alternative for its storage can improve this food, especially with respect to the quality of the fibers.