Olive Pulp Research Articles

Mechanical characteristics of individual bio particles

The current work presents an experimental procedure to determine the mechanical characteristics of individual biomass particulate materials, including comparatively spherical olive pulp particles and hollow cylindrical hay particles. This study also provides a comparison between the mechanical characteristics of wet and dry olive pulp particles. The strength and elastic properties of olive pulp particles were measured by conducting an uniaxial compression tests. For hay particles, the properties were measured by conducting compression tests in axial and radial directions, and three-point bending tests. The analysis of radial compression tests with hollow cylindrical particles was introduced in this paper, using the theory underlying the analysis of curved beams subjected to bending. The results indicated that small soft olive pulp particles are stronger and stiffer than large particles, and that wet olive pulp particles are weaker and softer than dry particles.

Aerobic industrial processing of Empeltre cv. natural black olives and product characterisation

SummaryThe fermentation of natural black olives is currently carried out under anaerobic conditions. This work investigates the aerobic fermentation of this product in tanks containing 16 000 kg of Empeltre olives during two seasons. The microorganisms in brines were yeasts in all cases, whereas lactic acid bacteria growth was only observed in some tanks. Consequently, the pH during fermentation was in most cases higher than recommended 4.3 units. However, the Empeltre olive brines displayed bactericidal effect against Salmonella enterica, Sthapylococcus aureus, Escherichia coli and Listeria monocytogenes, with a 5 log population drop in one or 24 h depending on the brine age so that these olive brines are a harsh environment for the growth of these pathogens. It was found HyEDA as the major phenolic compound in both brine and olive pulp at the beginning of fermentation that slowly hydrolysed into hydroxytyrosol that reached a concentration up to 1500 mg kg−1.

Lipidomic Profiling of the Olive (Olea europaea L.) Fruit towards Its Valorisation as a Functional Food: In-Depth Identification of Triacylglycerols and Polar Lipids in Portuguese Olives.

Olives (Olea europaea L.) are classic ingredients in the Mediterranean diet with well-known health benefits, but their lipid composition has not been fully addressed. In this work, we characterised triacylglycerol (TAG) and polar lipid profiles of the olive pulp while using a complementary methodological approach that was based on solid-phase extraction to recover the neutral lipid (NL) and the polar lipid-rich fractions. The TAG profile was analysed in the NL-fraction by C30 reversed-phase liquid chromatography (LC) and the polar lipid profile by normal-phase hydrophilic interaction liquid chromatography (HILIC), with both being coupled to electrospray ionization-mass spectrometry (ESI-MS) and ESI-MS/MS. This approach identified 71 TAG ions that were attributed to more than 350 molecular species, with fatty acyl chain lengths from C11:0 to C26:0, including different polyunsaturated acyl chains. The polar lipids included 107 molecular species that belonged to 11 lipid classes that comprised phospholipids, glyceroglycolipids, glycosphingolipids, and betaine lipids. In addition to polyunsaturated fatty acids, some of the phospholipids, glycolipids, and glycosphingolipids that were identified in the olive pulp have been described as biologically active molecules. Lipidomic phenotyping of the olive pulp has led to the discovery of compounds that will allow for a better assessment of its nutritional value and new applications of bioactive lipid components in this functional food.

Beneficial effect of feeding olive pulp and <i>Aspergillus awamori</i> on productive performance, egg quality, serum/yolk cholesterol and oxidative status in laying Japanese quails

Beneficial effect of feeding olive pulp and <i>Aspergillus awamori</i> on productive performance, egg quality, serum/yolk cholesterol and oxidative status in laying Japanese quails

Patè Olive Cake: Possible Exploitation of a By-Product for Food Applications.

Patè Olive Cake (POC) is a new by-product derived from recently introduced new decanters in the olive oil production process. POC, is essentially composed of water, olive pulp and olive skin, and is rich in several valuable bioactive compounds. Moreover, it still contains about 8–12% residual olive oil. We characterized the main bioactive compounds in POC from black olives (cv. Leccino and Cellina di Nardò) and also verified the biotechnological aptitude of selected yeast and lactic acid bacteria from different sources, in transforming POC into a new fermented product. The strategy of sequential inoculum of Saccharomyces cerevisiae and Leuconostoc mesenteroides was successful in driving the fermentation process. In fermented POC total levels of phenols were slightly reduced when compared with a non-fermented sample nevertheless the content of the antioxidant hydroxytyrosol showed increased results. The total levels of triterpenic acids, carotenoids, and tocochromanols results were almost unchanged among the samples. Sensory notes were significantly improved after fermentation due to the increase of superior alcohols, esters, and acids. The results reported indicate a possible valorisation of this by-product for the preparation of food products enriched in valuable healthy compounds.

Effects of dietary dried olive pulp inclusion on growth performance and meat quality of broiler chickens

Two hundred 10-d-old broiler chickens were used to study the effects of different dried olive pulp (DOP) inclusion rates on growth performance and meat quality. Broiler chickens were assigned to 4 experimental treatments (5 replicates of 10 broiler chickens each) for 32 d. The broiler chickens of each treatment were offered a different combination of grower (d 11 to 22; grower phase) and finisher (d 23 to 42; finisher phase) diets in terms of DOP content. The experimental treatments were: control (C), grower and finisher diets with no DOP; treatment 1 (T1), grower and finisher diets with 25 and 50 g DOP/kg, respectively; treatment 2 (T2), grower and finisher diets with 50 g DOP/kg; and treatment 3 (T3), grower and finisher diets with 50 and 80 g DOP/kg, respectively. Feed intake and body weight were recorded to calculate weight gain and feed conversion ratio (FCR). Fatty acid (FA) composition, oxidative stability, pH at 24 h post-mortem (pH24), color properties, cooking loss, and tenderness (as shear force) were determined in the breast muscle obtained from 2 broiler chickens/replicate pen of each treatment at d 42. The FCR was greater in T2 and T3 compared to C (P = 0.013) during the grower phase. During the finisher phase, FCR was greater in T3 when compared to C (P = 0.014), and to T1 and T2 (P = 0.031). The addition of DOP increased 18:1n-9 and total monounsaturated FA (P < 0.001) in the breast muscle in a dose dependent manner. Reduced oxidative stability, lower pH24, and increased lightness of breast meat in T3 compared with C (P = 0.003, 0.004, and 0.001, respectively), and with T1 and T2 (P = 0.004, 0.020, and 0.012, respectively) were observed at d 42. In conclusion, broiler chickens utilize DOP supplemented diets more efficiently when dietary DOP inclusion is increased gradually with age, i.e., by using a combination of grower and finisher diets with a maximum of 25 and 50 g DOP/kg, respectively. Breast meat can be enriched with 18:1n-9 FA by DOP addition; however, DOP should not exceed 50 g/kg diet because it can be detrimental to breast meat oxidative stability, pH24, and color.

Production of split table olives of the Cobrançosa cultivar: a kinetic study of the fermentation profile

The aim of this study was to evaluate the effect of the Cobrancosa cultivar olive ripeness on the physicochemical parameters and model their progression profile throughout the fermentation period. Green and turning color olives undertook fermentation due to fruit and environmental microbiota resulting in final brines with the required acidity values and absence of coliforms, Escherichia coli, Salmonella and Listeria monocytogenes. The Monod model was used to explain the changes of aW, total acidity and total phenolic content in the brines, and the same kinetic with inhibition was fitted to the changes of reducing sugar concentration in the brines. The inverse power model was adjusted to salt content in brines, aW, total acidity, reducing sugars and total phenolic content in the olives. The Naperian logarithmic function was fitted to the changes of the surface color parameter (− a/b) of the fruits. For both olives, the models adjusted to the experimental data were the same, showing a similar trend in the physicochemical profiles, probably due to the previously fruit splitting, which promotes nutrients diffusing into the brines and the influx of salt into the olives during fermentation. However, different model parameters were estimated, depending on the ripeness degree, namely for total acidity, reducing sugars and total phenolic content of the brines, showing lower nutrients diffusion rates from the unripe olive pulp, through the skin into the brine, due to the hardness of the cell wall structures in this maturation stage.

Application of electrical impedance spectroscopy and rheology to monitor changes in olive (Olea europaea L.) pulp during cold-pressed oil extraction

Cellular changes during cold-pressed extraction of ‘J5’ olives (Olea europaea L.) were investigated to better understand factors that affect oil release and recovery. Electrical impedance, electrical conductivity, rheological flow properties and light microscopy were used to monitor flesh or pulp structure at defined steps during the extraction process (grinding, malaxing and decanting). Light microscopy revealed most parenchyma cells in the flesh were ruptured in the grinding step. A significant reduction in electrical impedance concurrent with an increase in conductivity of tissue that occurred when cells were ruptured during the grinding process. Malaxing assisted aggregation of oil into larger droplets, observed by microscopy. Increasing malaxing time resulted in a decrease in the storage modulus (G′) of olive pulp, which correlated with the oil droplets in the olive paste coalescing together and becoming larger. The extraction process can be monitored with different techniques to assist with improved extraction yields.

One stage olive mill waste streams valorisation via hydrothermal carbonisation

An olive waste stream mixture, coming from a three phase-continuous centrifugation olive oil mill industry, with a typical wet basis mass composition of olive pulp 39 wt%, kernels 5 wt% and olive mill waste water 56 wt%, was subjected to hydrothermal carbonisation (HTC) at 180, 220 and 250 °C for a 3-hour residence time in a 2-litre stainless steel electrically heated batch reactor. The raw feedstock and corresponding hydrochars were characterised in terms of proximate and ultimate analyses, higher heating values and energy properties. Results showed an increase in carbonisation of samples with increasing HTC severity and an energy densification ratio up to 142% (at 250 °C). Hydrochar obtained at 250 °C was successfully pelletised using a lab scale pelletiser without binders or expensive drying procedures. Energy characterisation (HHV, TGA), ATR-FTIR analysis, fouling index evaluation and pelletisation results suggested that olive mill waste hydrochars could be used as energy dense and mechanical stable bio-fuels. Characterisation of HTC residues in terms of mineral content via induced coupled plasma optical emission spectroscopy (ICP-OES) as well as Total and Dissolved Organic Carbon enabled to evaluate their potential use as soil improvers. Nutrients and polyphenolic compounds in HTC liquid fractions were evaluated for the estimation of their potential use as liquid fertilisers. Results showed that HTC could represent a viable route for the valorisation of olive mill industry waste streams.

Effect of inclusion irradiated olive pulp in laying quail diets on biological performance

A feeding trial was conducted to study the effect of replacing yellow corn ingredient as the major energy source in laying Japanese quail diets by 0, 5 and 10% each irradiated Olive Pulp (IOP) or un-irradiated Olive Pulp (OP). A total of 216 laying Japanese quail, 12 weeks-old were randomly divided into six equal treatments (36 birds/treatment) with three replicates (8 female, 4 male in each). The experiment was lasted for six weeks to evaluate OP or IOP as a source of nutrients. The results obtained could be summarized as follows: 1). There was a significant (P ≤ 0.05) increase in egg production, egg weight and feed efficiency, fertility, hatching percentage and hatching weight when IOP was fed at levels up to 10%. 2). There was a significant (P ≤ 0.05) increase in blood heamalotogical parameters when IOP was fed at levels up to 10%. 3). OP had no significant effect on egg quality measurements, except for yolk weight % and yolk colour values, they recorded significant (P ≤ 0.05) increase in diets including IOP up to 60 g/kg. 4). It seems that replacing of IOP up to 10% in layers diets had the highest relative economic efficiency. Therefore, it could be concluded that IOP can be used in laying quail diets at levels up to 10% on the expense of dietary yellow corn without detrimental effects on their biological performance.

Effect of biochar origin and soil pH on greenhouse gas emissions from sandy and clay soils

Emissions of greenhouse gases (GHGs), such as carbon dioxide (CO2) and nitrous oxide (N2O) have great impact on global warming and atmospheric chemistry. Biochar addition is a potential option for reducing GHGs emissions through carbon (C) sequestration and N2O mitigation. However, the influences of biochar on C and nitrogen (N) transformations in soil are still unclear, resulting in a poor understanding of the mechanisms of N2O mitigation effects of biochar. Here we carried out two soil incubation experiments to investigate the influence of two common biochars addition (corn cob and olive pulp) with ammonium sulfate on CO2 and N2O emissions from two contrasting soil types (acidic sandy and alkaline clay soil). Furthermore, four extracellular enzymes activities that related to C and N cycling, i.e. cellobiohydrolase, chitinase, xylanase and β-glucosidase, were analyzed to gain insights into the underlying mechanisms of biochar’s effects on CO2 and N2O evolutions. Contrasting effects of two biochars on CO2 and N2O emissions were observed in the two different soils. The corn biochar addition had no significant effect on CO2 and N2O emissions in the alkaline clay soil, but significantly decreased CO2 emissions by 11.8% and N2O emissions by 26.9% in the acidic sandy soil compared to N-fertilizer only treatment. In contrast, olive biochar addition showed no significant effect on CO2 emissions but decreased N2O emissions by 34.3% in the alkaline clay soil, while in the acidic sandy soil addition of olive biochar triggered about a twofold higher maximum CO2 emission rate and decreased N2O emissions by 68.4%. Up to 50–130% higher specific CO2 emissions (per unit of C-related enzyme activity: cellobiohydrolase, chitinases and β-glucosidase) were observed after addition of olive biochar compared to corn biochar addition in the acidic sandy soil. We concluded that biochar’s effects on N2O and CO2 emissions are more pronounced in acidic soils. Alkaline biochar’s N2O mitigation potential in acidic soils seems to be dependent on soil NO3− content as drastically higher N2O emissions were measured in early phase of the experiment (where soil NO3− was high) and significantly lower N2O fluxes were obtained in later phases (with lower soil NO3− content).

Kaolin and salicylic acid foliar application modulate yield, quality and phytochemical composition of olive pulp and oil from rainfed trees

Abstract Olive orchards, rainfed managed, are threatened by the current and predicted adverse environmental conditions, which change the yield and quality of olive products, largely known for its benefits to human health. To mitigate these problems, it is highly recommended to perform some adjustments in agronomic practices, such as the use of foliar sprays that cloud help the trees to cope with climate change. During two consecutive years, olive trees were pre-harvest sprayed with kaolin (KL) and salicylic acid (SA) to attenuate the adverse effects of summer stress. Olive yield was increased by 97% and 72% with KL and SA, respectively. Phenolics and antioxidant capacity of both olives and olive oil increased and decreased in the first and second year, respectively, in a closely association with the prevailing climatic conditions. The foliar sprays did not significantly affect the oil quality indices, free acidity, peroxide value and K232 coefficient and decreased the K270 coefficient. This study strongly suggests that the applied products might be effective in mitigating the adverse environmental conditions, without substantial changes in fruit and olive oil quality.

Effect of ethephon application on the cellular maturity of Olea europaea L. and on the extractability of phenolic compounds in virgin olive oil

BackgroundThe effect of the ethephon application at fruit set and veraison on cell maturity of Olea europaea L. olives and on the extractability of phenolic compounds (PC) in virgin olive oil has been studied.MethodsThe ethephon was sprayed on olive trees of the Moroccan Picholine at the fruit set stage and on other olive trees at the veraison stage at a concentration of 100 mg/L. The effect of these treatments was evaluated by the fruit yield and the determination of the period of olives growth and ripening. The extractability of the olive oil and the diffusion of the PCs in the fat as well as the embrittlement of the parietal structures are also monitored.Results and conclusionsA chemical thinning is entrained out by ethephon when applied at fruit set (16%) or veraison (12%). It also results in precocious ripening of fruits treated at fruit set (about 2 weeks) and a precocity of the harvest similar to that induced in olives treated at veraison (estimated at 6 weeks). At this stage, a significant increase in the fat accumulation (more than 26 g/100 g in the olives treated compared to 7.7 g/100 g olive pulp in the control) and quantities of extracted oils (87 and 83%, respectively, in the olives treated at fruit set and those treated at veraison compared to 70% in the control) as well as a significant improvement in the extractability of the diffusible PCs in these oils at maturity (540 and 590 mg/kg, respectively, in the treated olives at fruit set and those treated at veraison compared to 216 mg/kg in the control oil).

Rhizopus oryzae as Fermentation Agent in Food Derived Sub-products

The present research describes the use of Rhizopus oryzae as bioconversion agent of different agro-industrial by-products (fruit wastes, olive pulp cake, coffee grounds and potato peels) by solid state fermentation at different experimental conditions to enhance their value as animal feed. Results showed that R. oryzae grows better at fruit wastes than in other by-products. Fermentation process produced a protein and fat rich mycelia [respectively, 7.8 ± 1.2 and 9.0 ± 0.4% of dry matter (DM)] and reduced the carbohydrates content of considered by-products from 60.6 ± 0.4 to 40.1 ± 0.3% DM in 3 days. Supplementation with different nitrogen sources increases dramatically the protein concentration in the mycelia up to 46.8 ± 0.7% of DM. After fermentation, amino acid profile changed in the fermented product, with significant enrichment of several essential amino acids like valine, leucine, threonine, isoleucine and arginine and lower aspartate concentration. In conclusion, obtained product can be a high value alternative for animal feed.

The Influence of pH and Sodium Hydroxide Exposure Time on Glucosamine and Acrylamide Levels in California-Style Black Ripe Olives.

Acrylic acid, N-acetyl-glucosamine and glucosamine were investigated for their role in the formation of acrylamide in California-style black ripe olives [CBROs]. Levels of acrylic acid and glucosamine are reported for the first time in fresh (333.50 ± 21.88 and 243.59 ± 10.06 nmol/g, respectively) and in brine-stored olives (184.50 ± 6.02 and 165.88 ± 11.51 nmol/g, respectively). Acrylamide levels significantly increased when acrylic acid (35.2%), N-acetyl-glucosamine (29.9%), and glucosamine (124.0%) were added to olives prior to sterilization. However, isotope studies indicate these compounds do not contribute carbon and/or nitrogen atoms to acrylamide. The base-catalyzed degradation of glucosamine is demonstrated in olive pulp and a strong correlation (r2 = 0.9513) between glucosamine in olives before sterilization and acrylamide formed in processed CBROs is observed. Treatment with sodium hydroxide (pH > 12) significantly reduces acrylamide levels over 1 to 5 d without impacting olive fruit texture.

Integrated approach for the eco design of a new process through the life cycle analysis of olive oil: Total use of olive by‐products

The disposal of waste is one of the main problems faced by the majority of the olive growing agribusiness: olive oil by‐products require specific management. In this work, the result of life cycle analysis shows that the major problem is related to the management of mill waste water. The formation of compost from the depleted pomace is bound to the emission of greenhouse gases. Therefore, the traditional way of waste recovery is no longer the best alternative. In this context, we propose a complete process for total use of olive by‐products during the process of olive oil extraction. The project presents a pulp olive oil rich in natural antioxidants, stone olive oil for cosmetic application and an olive paste with a smoky taste for food consumption. The proposed system contributes to lower the environmental impact, improve the quality of the oil, and promote the development of new and useful by‐products.Practical applications: A new facility composed of a destoner and a two phase extraction system is proposed to improve the working capacity and contribute to lower the environmental impact during all the process of olive oil production. The proposed new system produces, on the one hand, an olive pulp that gives an extra virgin olive oil rich in natural antioxidants and an olive paste with a smoky taste for food consumption, and on the other hand, stones that gives an olive oil for cosmetic application and a raw material to produce energy.Life cycle analysis of olive oil is used as a tool to design a new production process in olive growing agribusiness for cleaner production. The new facility, composed of a destoner and a two phase extraction system, improves the working capacity and contributes to lower the environmental impact. It produces an olive pulp that gives, on the one hand, an extra virgin olive oil rich in natural antioxidants and an olive paste with a smoky taste for food consumption, and, on the other hand, stones that gives an olive oil for cosmetic application and raw material for producing energy.

From olive waste to solid biofuel through hydrothermal carbonisation: The role of temperature and solid load on secondary char formation and hydrochar energy properties

Hydrothermal carbonisation was used to upgrade fuels from two types of agro-industrial wastes: olive tree trimmings and olive pulp. Hydrochar yield, elemental and proximate analyses, thermal stability, higher heating value (HHV), and energy yield at different reaction temperatures (120, 150, 180, 200, 220, 235 and 250°C) and solid load (biomass to water ratios − B/W − equal to 7, 10, 15 and 25%) were assessed for a fixed reaction time of 30min. HHV varied linearly with hydrochar mass yield and reaction temperature in the temperature range 180–250°C. Solid load proved to be a crucial parameter in determining the energy properties of hydrochars. The higher B/W, the higher were the degree of carbonisation (in terms of fixed and total carbon), the hydrochar HHV, and the hydrochar yield. Elemental analysis showed that during HTC, olive pulp samples underwent a greater degree of carbonisation when compared to the corresponding olive tree trimmings residues. High solid load and high reaction temperature promoted secondary char formation. Secondary char showed a sphere-like structure formed by overlapping layers. EDS microanalysis showed that secondary char is characterised by a significantly higher carbon content than parent primary char, thus confirming its contribution towards enhancing the HHV of hydrochars.

An environmentally friendly process for the production of extracts rich in phenolic antioxidants from Olea europaea L. and Cynara scolymus L. matrices

A sustainable extractive technology followed by membrane separation methods was applied to Olea europaea L. (leaves and pitted olive pulp) and Cynara scolymus L. by-products (leaves and stems), to obtain different standardized commercial extracts for application in the functional food industry, pharmaceutical and cosmetic fields. The entire treatment, PCT registered, consists of water extraction of the aforementioned vegetal material and the following steps of fractionation: (1) microfiltration (only for Olea); (2) ultrafiltration (only for Cynara); (3) nanofiltration (only for Olea); (4) reverse osmosis and final concentration by evaporation at low temperature or spray-dried technique. Thanks to these steps, different fractions enriched with phenolic compounds that have an economic value can be obtained. These fractions were characterized and quantified by HPLC/DAD-ESI/MS and then tested for their antiradical and antioxidant properties. The EC50 values by DPPH test were 6.76 × 10−3 mM for the Olea green leaves (GL) soft extract, 5.44 × 10−3 mM for the Olea dried leaves (DL) soft extract, and 1.22 × 10−3 mM in the case of the Olea OH-Tyr soft extract. The EC50 value of the Cynara GL soft extract was 3.25 × 10−3 mM. The ORAC results were 3632 ± 110.7 µmoL TE/g for OH-Tyr Olea soft extract, 1410 ± 62.1 µmoL TE/g for GL Olea soft extract, and finally 760 ± 12 µmoL TE/g for GL Cynara soft extract, confirming the highest antioxidant activity of hydroxytyrosol.

Retention of color and volatile compounds of Spanish-style green table olives pasteurized and stored in plastic containers under conditions of constant temperature

Spanish-style green table olives pasteurized and stored in two types of pasteurizable plastic pouches and glass bottles were analyzed for color parameters and volatile components after 6.5 months of storage at 30 °C. Color parameters in pouches made of aluminium oxide coating on polyethylene terephthalate + medium-density polyethylene (AlOx-coated PET + MDPE) were acceptable and, in general, did not significantly differ from those in glass, but unacceptable values corresponding to dark visual colors of both olives and brine were found in pouches made of polyethylene terephthalate + medium-density polyethylene/ethylene vinyl alcohol (PET + MDPE/EVOH). Forty-three volatile compounds were identified and quantified in olive pulp by solid phase micro-extraction (SPME) and gas chromatography coupled to mass spectrometry (GC-MS), 36 of these compounds being significantly different between the plastic and glass treatments. The type of plastic container had an impact on the volatile composition of product. Oxidation and scalping were considered to be the most probable causes for the differences in volatile components between PET + MDPE/EVOH pouches and glass containers, but in AlOx-coated PET + MDPE pouches no oxidation process was apparent.

Sustainability, Innovation, and Green Chemistry in the Production and Valorization of Phenolic Extracts from Olea europaea L.

This paper describes a circular economy process based on environmentally and economically sustainable procedures which was applied to the sector of olive oil processing on an industrial scale. Olea europaea L. tissues and by-products represent a renewable and low-cost source of polyphenols, in particular hydroxytyrosol (HTyr), a naturally occurring compound well known for its biological properties. Specifically, green leaves (GL), dried leaves (DL), and pitted olive pulp were treated with water in a pneumatic extractor to obtain the corresponding polyphenolic extracts. Three standardized fractions, named Soft Extract Olea GL, Soft Extract Olea DL, and Soft Extract Olea HTyr resulted after the following two steps: a separation process carried out by membrane technology, and a concentration step performed under reduced pressure and low temperature. The polyphenolic fractions showed antiradical activity and have potential industrial applications in the food, nutraceutical, pharmaceutical, feed, and agronomic fields. Novel functionalized extracts containing hydroxytyrosol methyl carbonate (HTyr-MC) were obtained from Soft Extract Olea HTyr through an innovative approach based on green chemistry procedures, which appear to be a promising tool to increase the applications of the polyphenolic extracts.