Dry Olive Cake Research Articles

Effects of alternative feedstuffs on growth performance, carcass characteristics, and meat quality of growing Awassi lambs

Twenty-seven Awassi lambs were used to evaluate the effects of dietary inclusion of selected (dry bread, carob pods, olive cake, and sesame meal) alternative feedstuffs (AF) on performance, carcass characteristics, and meat quality. Lambs were assigned to one of three treatment diets. Diets contained (g/kg on DM basis) no (0AF; n = 9), 250 (25AF; n = 9), or 500 (50AF; n = 9) of AF, respectively. Lambs fed the 50AF diet had the least (p < .05) intake of DM, OM, NDF, and ME. Crude protein digestibility was lowest (p < .01) in lambs fed the 50AF diet. The digestibility of NDF and ADF was highest (p < .01) for the 0AF diet. Hot and cold carcass weights tended to be greater (p ≤ .10) for lambs fed with the 0AF than the 50AF diet. Dressing percentage tended to be lower (p = .07) in lambs fed with the 50AF compared to the 0AF and 25AF diets. No substantial differences were observed among dietary treatments in carcass and non-carcass cut weights. Composition (muscle, fat, and bone) of dissected legs were not different (p ≥ .10) among dietary treatments. No substantial differences (p ≥ .37) were observed among dietary treatments in all meat quality parameters except for higher redness of the 0AF diet. Dietary inclusion of AF at 250 or 500 g/kg decreased production cost with similar feed conversion ratio. However, at high level (500 g/kg) AF could negatively affect nutrients intake, digestibility, and performance.HighlightsReplacing conventional feedstuffs from lamb diets with two levels (250 or 500 g/kg) of alternative feedstuffs reduced production cost without causing any health problems to lambs.

Nutrient Availability in a Calcareous Soil Amended with Different Types of Biomass Ash

ABSTRACTAn incubation experiment was conducted to evaluate the effects that three types of biomass ash, each applied at two doses, exert on the nutrient availability in a calcareous soil. The application of the ash from dry olive cake or greenhouse vegetable wastes significantly increased soil ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA)-extractable phosphorus (P), potassium (K), sodium (Na), copper (Cu) and zinc (Zn) as well as exchangeable and non-exchangeable K and Na. Wood ash was effective only for increasing soil ABDTPA-extractable Zn and Cu. By contrast, the three types of biomass ash hardly increased soil ABDTPA-extractable Fe or Mn. The high content in carbonate of the soil appears to minimize the potential of the ash to increase the micronutrients availability, which shortened with longer incubation time. Soil ABDTPA-extractable heavy metals were not detected in the different treatments tested. Other parameters of the soil, as pH and organic carbon, were scarcely affected by the ash, while conductivity and dehydrogenase activity increased.

Soil-nutrient availability affected by different biomass-ash applications

This study, through an incubation experiment, evaluates the effect that different biomass ashes exert on the extractability of nutrients and some chemical parameters and dehydrogenase activity of a slightly acid soil. Three types of as were selected: two new ashes generated by the dry combustion of olive cake or by gasification of greenhouse vegetable wastes, and a third produced by wood combustion. The ash significantly increased the pH, electrical conductivity, and dehydrogenase activity of the soil. Dry olive-cake ash was the most effective in raising the levels of soil AB-DTPA extractable P, K, and Cu. By contrast, wood ash caused the greatest increases in soil AB-DTPA-extractable Zn. The three as he showed little effectiveness for increasing soil ABDTPA extractable Fe and Mn. Ash from dry olive cake could be used as a low-cost potassium fertilizer.

Identification of predictor parameters to determine agro-industrial compost suppressiveness against Fusarium oxysporum and Phytophthora capsici diseases in muskmelon and pepper seedlings.

The lack of reliable prediction tools for evaluation of the level and specificity of compost suppressiveness limits its application. In our study, different chemical, biological and microbiological parameters were used to evaluate their potential use as a predictor parameter for the suppressive effect of composts against Fusarium oxysporum f. sp. melonis (FOM) and Phytophthora capsici (P. capsici) in muskmelon and pepper seedlings respectively. Composts were obtained from artichoke sludge, chopped vineyard pruning waste and various agro-industrial wastes (C1: blanched artichokes; C2: garlic waste; C3: dry olive cake). Compost C3 proved to offer the highest level of resistance against FOM, and compost C2 the highest level of resistance against P. capsici. Analysis of phospholipid fatty acids isolated from compost revealed that the three composts showed different microbial community structures. Protease, NAGase and chitinase activities were significantly higher in compost C3, as was dehydrogenase activity in compost C2. The use of specific parameters such as general (dehydrogenase activity) and specific enzymatic activities (protease, NAGase and chitinase activities) may be useful to predict compost suppressiveness against both pathogens. The selection of raw materials for agro-industrial composts is important in controlling Fusarium wilt and Phytophthora root rot.

Feeding olive cake to ewes improves fatty acid profile of milk and cheese

Olive oil extraction yields a residual cake rich in oil that can be used in animal diets as a source of monounsaturated fat. Milk and cheese from sheep are high in saturated fatty acids (FA) thus, it was hypothesized that supplementing olive cake to lactating ewes would result in naturally enhanced milk and cheese with healthier FA profiles for human consumption. Nine lactating ewes were randomly assigned to a replicated (n=3) 3×3 Latin square design. Diets were supplemented with 0, 10 or 25% of dry olive cake. Except for total solids, dry matter intake, milk yield and milk composition were not affected by dietary treatments. Oleic acid, n-6/n-3 ratio and monounsaturated FA gradually increased (P<0.05), while saturated FA and atherogenicity index decreased (P<0.05) in milk and cheese as inclusion of olive cake was increased in dietary treatments. Overall, FA profile of milk and cheese from sheep can be naturally improved by supplementation of olive cake.

The effectiveness of arbuscular-mycorrhizal fungi and Aspergillus niger or Phanerochaete chrysosporium treated organic amendments from olive residues upon plant growth in a semi-arid degraded soil

Arbuscular mycorrhizal (AM) fungi and a residue from dry olive cake (DOC) supplemented with rock phosphate (RP) and treated with either Aspergillus niger (DOC-A) or Phanerochaete chrysosporium (DOC-P), were assayed in a natural, semi-arid soil using Trifolium repens or Dorycnium pentaphyllum plants. The effects of the AM fungi and/or DOC-A were compared with P-fertilisation (P) over eleven successive harvests to evaluate the persistence of the effectiveness of the treatments. The biomass of dually-treated plants after four successive harvests was greater than that obtained for non-treated plants or those receiving the AM inoculum or DOC-A treatments after eleven yields. The AM inoculation was critical for obtaining plant growth benefit from the application of fermented DOC-A residue. The abilities of the treatments to prevent plant drought stress were also assayed. Drought-alleviating effects were evaluated in terms of plant growth, proline and total sugars concentration under alternative drought and re-watering conditions (8th and 9th harvests). The concentrations of both compounds in plant biomass increased under drought when DOC-A amendment and AM inoculation were employed together: they reinforced the plant drought-avoidance capabilities and anti-oxidative defence. Water stress was less compensated in P-fertilised than in DOC-A-treated plants. DOC-P increased D. pentaphyllum biomass, shoot P content, nodule number and AM colonisation, indicating the greater DOC-transforming ability of P. chrysosporium compared to A. niger. The lack of AM colonisation and nodulation in this soil was compensated by the application of DOC-P, particularly with AM inoculum. The management of natural resources (organic amendments and soil microorganisms) represents an important strategy that assured the growth, nutrition and plant establishment in arid, degraded soils, preventing the damage that arises from limited water and nutrient supply.

EFFECTIVENESS OF THE APPLICATION OF ARBUSCULAR MYCORRHIZA FUNGI AND ORGANIC AMENDMENTS TO IMPROVE SOIL QUALITY AND PLANT PERFORMANCE UNDER STRESS CONDITIONS

Plant growth is limited in arid and/or contaminated sites due to the adverse conditions coming from heavy metal (HM) contamination and/or water stress. Moreover, soils from these areas are generally characterised by poor soil structure, low water-holding capacity, lack of organic matter and nutrient deficiency. In order to carry out a successful re-afforestation, it is necessary to improve soil quality and the ability of plants species to resist this harsh environment. The symbiosis with arbuscular mycorrhizal (AM) fungi has been proposed as one of the mechanisms of plant heavy metal tolerance and water stress avoidance. On the other hand, addition of organic amendments to the soil can reverse degradation of soil properties. Agro-waste residues such as dry olive cake (DOC) and sugar beet waste (SB) supplemented with rock phosphate (RP) can be used as organic amendments after fermentation by Aspergillus niger. The application of A. niger- treated DOC and/or SB to semi-arid soils and/or HM-contaminated soils increased aggregate stability, soil enzymatic activities, water soluble C and water soluble carbohydrates as well as nutrient availability, especially P. AM inoculation, using adapted endophytes, was more efficient with respect to increasing plant nutrition and growth as well as plant tolerance to drought or HM-stress conditions. The combined treatments involving mycorrhiza fungi inoculation and addition of the amendments into the soil can be proposed as a successful revegetation strategy for plant performance in P-deficient soils under semiarid Mediterranean conditions. The beneficial effectiveness of this symbiosis with suitable AM fungi in A. niger-treated agro-waste residue-amended soil can also be regarded as a successful biotechnological tool for reclamation of HM-contaminated soils.

The interactive effect of an AM fungus and an organic amendment with regard to improving inoculum potential and the growth and nutrition of Trifolium repens in Cd-contaminated soils

Aspergillus niger-treated dry olive cake (DryOC) can be used as a soil organic amendment and the aim of this work was to study the effectiveness of this amendment and a Cd-adapted arbuscular mycorrhizal (AM) fungus in improving Trifolium repens growth and nutrition in Cd-contaminated soil. In a compartmentalized growth system, consisting of a root compartment (RC) and two hyphal compartments (HCs), we investigated the influence of the amendment on intraradical and extraradical AM fungi development. In addition, we studied the viability and infectivity of the detached extraradical mycelium in plants, designated as receptor plants, grown in the HC after removal of the RC. Both the amendment and the AM fungus increased shoot and root biomass and nodulation in both the non-contaminated and Cd-contaminated soils. The positive interaction between the microbiologically treated DryOC and the AM fungus resulted in the highest plant yield, which can be explained by enhanced nutrient acquisition and arbuscular richness as well as by the immobilisation of Cd in amended soils. However, A. niger-treated DryOC had no effect on the extraradical mycorrhizal mycelium development. Although Cd decreased AM hyphal length density, symbiotic infectivity was similar in receptor plants grown in non-contaminated and contaminated soil, thus confirming the AM fungal inoculum potential. The combination of the AM fungus and A. niger-treated DryOC increased plant tolerance to Cd in terms of plant growth and nutrition and can be regarded as an important strategy for reclaiming Cd-contaminated soils.

Feeding Dry Olive Cake Modifies Subcutaneous Fat Composition in Lambs, Noting Cake Resistance to Degradation and Peroxidation

The purpose of this experiment was to determine the extent to which lamb carcass quality and fat composition could be altered by applying a dry olive cake-based ration instead of a conventional ration or pasture feeding. Three treatments were compared in a completely randomized experiment using 36 single male Suffolk Down lambs with an initial age and live weight of 80 d and 25 kg, respectively. The three treatments were: (a) suckling lambs kept with their mothers on annual Mediterranean grassland (GRAZE); (b) weaned stall-fed lambs on a control ration (CONC); and (c) weaned stall-fed lambs on an olive cake-based ration (CAKE). At the end of the 28-d experimental period, lambs were slaughtered, carcass quality evaluated, and samples of subcutaneous fat analyzed for fatty acids. Treatments did not differ in weight gain or carcass weight and quality, but highly significant differences were found in several fatty acid contents. CAKE animals had reduced palmitic acid as well as increased oleic and stearic acid contents. Atherogenic and thrombogenic indices improved with cake feeding. Principal component and discriminant analyses clearly differentiated treatments suggesting they could be applicable for traceability purposes. A laboratory experiment demonstrated that with or without added vitamin E, the dry olive cake did not alter its lipid properties with increased storage time.

Changes in biological activity of a degraded Mediterranean soil after using microbially-treated dry olive cake as a biosolid amendment and arbuscular mycorrhizal fungi

A field experiment was carried out to assess the effect of a combined treatment involving addition of Aspergillus niger-treated dry olive cake (DryOC) in the presence of rock phosphate, plus pre-transplant inoculation of seedlings with the arbuscular mycorrhizal (AM) fungi Glomus intraradices, Glomus deserticola or Glomus mosseae, on the establishment of Dorycnium pentaphyllum L., in a degraded semiarid Mediterranean area. Associated changes in soil labile C fractions, enzyme activities and aggregate stability were also observed. One year after planting, the combined treatment of fermented DryOC addition and inoculation with AM fungi, particularly with G. mosseae (on average 328% greater than control plants), had the strongest effect on the shoot biomass of D. pentaphyllum. Only the fermented DryOC addition increased assimilable P, total N and aggregate stability, the greatest increase being in the soil available P content (about four-fold higher than in the non-amended soil). Both the addition of fermented DryOC and the mycorrhizal inoculation treatments significantly increased enzyme activities of rhizosphere soil (dehydrogenase, protease-BAA, acid phosphatase and β-glucosidase). The microbially-treated DryOC proved to be an effective amendment for improving the soil quality which, in turn, enhanced the success of revegetation with mycorrhizal D. pentaphyllum seedlings.

Microbial solubilization of rock phosphate on media containing agro-industrial wastes and effect of the resulting products on plant growth and P uptake

Four agro-industrial wastes were assayed as substrates for microbial solubilization of rock phosphate (RP). Sugar beet wastes (SB), olive cake (OC) and olive mill wastewaters (OMWW) were treated by Aspergillus niger, and dry olive cake (DOC) was treated by Phanerochaete chrysosporium. In conditions of solid-state fermentation 46% of SB and 21% of OC were mineralized by A. niger while 16% of DOC was mineralized by P. chrysosporium. Repeated-batch mode of fermentation was employed for treatment of OMWW by immobilized A. niger, which resulted in conversion of 80% of the fermentable sugars. Acidification of all media treated by A. niger was registered with a simultaneous solubilization of 59.7% (SB), 42.6% (OC), and 36.4% (OMWW) of the total P present in the RP. The same mechanism of RP solubilization was observed in DOC-based medium inoculated with P. chrysosporium but other mechanisms were probably involved during the process. A series of microcosm experiments were then performed in the greenhouse to evaluate the effectiveness of the resulting fermented products. All amendments improved plant growth and P acquisition, which were further enhanced by mycorrhizal inoculation. The level of all studied parameters including the root mycorrhizal colonization depended on the substrate characteristics. The reported biotechnological schemes offer a potential application particularly for degraded soils.

Growth and nitrate reductase activity in Juniperus oxycedrus subjected to organic amendments and inoculation with arbuscular mycorrhizae

AbstractThe effectiveness of reforestation programs on degraded soils in the Mediterranean region is frequently limited by a low soil availability and a poor plant uptake and assimilation of nutrients. While organic amendments can improve the nutrient supply, inoculation with mycorrhizal fungi can enhance plant nutrient uptake. A pot experiment was conducted in 2004 to study the influence of inoculation with an arbuscular mycorrhizal (AM) fungus (Glomus intraradices Schenck &amp; Smith) or with a mixture of three AM fungi (G. intraradices, G. deserticola Trappe, Bloss. &amp; Menge, and G. mosseae (Nicol &amp; Gerd.) Gerd. &amp; Trappe) and of an addition of composted sewage sludge or Aspergillus niger–treated dry‐olive‐cake residue on plant growth, nutrient uptake, mycorrhizal colonization, and nitrate reductase (NR) activity in shoot and roots of Juniperus oxycedrus L. Six months after planting, the inoculation of the seedlings with G. intraradices or a mixture of three AM fungi was the most effective treatment for stimulating growth of J. oxycedrus. There were no differences between the two mycorrhizal treatments. All treatments increased plant growth and foliar N and P contents compared to the control plants. Mycorrhizal inoculation and organic amendments, particularly fermented dry olive cake, increased significantly the NR activity in roots.

Formation of stable aggregates in rhizosphere soil of Juniperus oxycedrus: Effect of AM fungi and organic amendments

The effects of mycorrhizal inoculation, with an arbuscular mycorrhizal (AM) fungus ( Glomus intraradices Schenck and Smith) or with a mixture of three AM fungi ( G. intraradices, G. deserticola (Trappe, Bloss. and Menge) and G. mosseae (Nicol and Gerd.) Gerd. and Trappe), and addition of composted sewage sludge or Aspergillus niger-treated dry olive cake (DOC) residue on aggregate stabilisation of the rhizosphere soil of Juniperus oxycedrus were studied. The influence of such structural improvements on the establishment of J. oxycedrus was evaluated. Six months after planting, the inoculation with the mixture of three AM fungi and the combination of G. intraradices with both organic amendments had significantly enhanced the structural stability. Water soluble C and carbohydrates values were increased only with the addition of composted sewage sludge or fermented DOC. The addition of both organic amendments, particularly fermented DOC, decreased significantly the dehydrogenase, urease, protease and β-glucosidase activities. Rhizosphere soil from the inoculation treatments had higher dehydrogenase and β-glucosidase activities than control soil. Both the organic amendments addition and the mycorrhizal inoculation treatments increased significantly shoot biomass in J. oxycedrus. AM inoculation treatments were more effective with respect to increasing shoot biomass than the addition of organic amendments alone, and there were no significant differences between the two mycorrhization treatments (on average, about 53% higher with respect to control plants and about 18% higher with respect to plants grown in the amended soil).

Hydrolytic enzyme activities of extracted humic substances during the vermicomposting of a lignocellulosic olive waste

Humic substances and three hydrolytic enzymes (β-glucosidase, phosphatase and urease) were extracted by neutral sodium pyrophosphate from an olive waste (dry olive cake), alone or mixed with municipal biosolids, during a nine month vermicomposting process. Easily degradable compounds decreased during the vermicomposting process because of microbial consumption. When municipal biosolids were added to dry olive cake, microbial activity increased and the amounts of compounds extracted by pyrophosphate were three times lower than olive cake alone. In both instances, β-glucosidase, phosphatase and urease activities of the organic extracts either increased or remained the same after a nine month period of vermicomposting, thus suggesting that the humus enzyme complexes resisted microbial and earthworm attack. It is known that humus immobilised enzymes also remain active in soil environments, reactivating the nutrient cycles in soil. The use as amendments of vermicomposted olive cake, alone or when mixed with biosolids, could be a good alternative to reactivate the C, P and N-cycles in degraded soils for regeneration purposes.

Improvement of soil characteristics and growth of Dorycnium pentaphyllum by amendment with agrowastes and inoculation with AM fungi and/or the yeast Yarowia lipolytica

The effectiveness of two microbiologically treated agrowastes [dry olive cake (DOC) and/or sugar beet (SB)] on plant growth, soil enzymatic activities and other soil characteristics was determined in a natural soil from a desertified area. Dorycnium pentaphyllum, a legume plant adapted to stress situations, was the test plant to evaluate the effect of inoculation of native arbuscular mycorrhizal (AM) fungi and/or Yarowia lipolytica (a dry soil adapted yeast) on amended and non-amended soils. Plant growth and nutrition, symbiotic developments and soil enzymatic activities were limited in non-amended soil where microbial inoculations did not improve plant development. The lack of nodules formation and AM colonization can explain the limited plant growth in this natural soil. The effectiveness and performance of inocula applied was only evident in amended soils. AM colonization and spores number in natural soil were increased by amendments and the inoculation with Y. lipolytica promoted this value. The effect of the inoculations on plant N-acquisition was only important in AM-inoculated plants growing in SB medium. Enzymatic activities as urease and protease activities were particularly increased in DOC amended soil meanwhile dehydrogenase activity was greatest in treatments inoculated with Y. lipolytica in SB added soil. The biological activities in rhizosphere of agrowaste amended soil, used as indices of changes in soil properties and fertility, were affected not only by the nature of amendments but also by the inoculant applied. All these results show that the lignocellulosic agrowastes treated with a selected microorganism and its further interaction with beneficial microbial groups (native AM fungi and/or Y. lipolytica) is a useful tool to modify soil physico-chemical, biological and fertility properties that enhance the plant performance probably by making nutrients more available to plants.

AM fungi inoculation and addition of microbially‐treated dry olive cake‐enhanced afforestation of a desertified Mediterranean site

AbstractA field experiment was carried out to compare the effectiveness of inoculation with three arbuscular mycorrhizal (AM) fungi, namely Glomus intraradices Schenck &amp; Smith, Glomus deserticola (Trappe, Bloss. &amp; Menge) and Glomus mosseae (Nicol &amp; Gerd.) Gerd. &amp; Trappe, and the addition of Aspergillus niger‐treated dry olive cake (DOC) in the presence of rock phosphate, in increasing root nitrate reductase (NR) and acid phosphatase activities, mycorrhizal colonization, plant growth and nutrient uptake in Dorycnium pentaphyllum L. seedlings afforested in a semiarid degraded soil. Three months after planting, both the addition of fermented DOC and the mycorrhizal inoculation treatments had increased root NR activity significantly, particularly the inoculation with G. deserticola (by 75 per cent with respect to non‐inoculated plants), but they had no effect on root acid phosphatase. Mycorrhizal inoculation treatments with G. deserticola or G. mosseae on their own were even more effective than the addition of fermented DOC alone in improving the growth and (NPK) foliar nutrients of D. pentaphyllum plants. The combined treatment involving the application of microbially‐treated agrowastes and mycorrhizal inoculation with AM fungi, particularly with G. mosseae, can be proposed as a successful revegetation strategy for D. pentaphyllum in P‐deficient soils under semiarid Mediterranean conditions. Copyright © 2004 John Wiley &amp; Sons, Ltd.

Vermicomposting of a lignocellulosic waste from olive oil industry: a pilot scale study.

The vermicomposting with Eisenia andrei of dry olive cake, a lignocellulosic waste produced during the extraction of olive oil, either alone or mixed with municipal biosolids, was studied in a nine-month pilot scale experiment. Number and biomass of earthworms and enzyme activities were periodically monitored and relevant properties of the final products were determined. In the assayed substrates, the total biomass of earthworms increased at the end of the experimental period between 9 and 12-fold respectively in comparison with the earthworm biomass initially inoculated. The increase in hydrolytic enzymes and overall microbial activity during the vermicomposting process indicated the biodegradation of the olive cake and resulted in the disappearance of the initial phytotoxicity of the substrate. However, the recalcitrant lignocellulosic nature of the dry olive cake prevented suitable humification during the vermicomposting process. For this reason, in addition to organic amendments, other management procedures should be considered.

Enzyme activities in the rhizosphere of pepper ( Capsicum annuum, L.) grown with olive cake mulches

Dry olive cake, alone or mixed with biosolids or cattle manure, was used to assess the ecological management of a degraded soil. These olive by-products had been stabilised previously for 160 days in a vermicomposting process. Unprocessed and vermicomposted products were used as organic mulches in a greenhouse experiment. The control contained only degraded soil. Soil biochemical activities (dehydrogenase, urease and phosphatase) were studied in the rhizosphere of pepper ( Capsicum annuum, L.). In addition, the changes in plant growth and nutrient content of C. annuum following addition of mulches were measured. The addition of dry olive cakes as organic mulches increased P concentration in pepper leaves from 1.5 to 4.5–5.7 g kg −1. Potassium concentration in leaves increased from 51 to 65–85 g kg −1, depending on the mulch assayed. In contrast, N concentrations were unaffected. Rhizosphere dehydrogenase activity increased by 1.5- to 2.5-fold by incorporation of mulches, either vermicomposted or not, when compared with the no-mulch control. This suggests that microbial numbers and potential activity in the rhizosphere were related to the addition of organic materials. Urease activity in the rhizosphere was inhibited, at least three-fold, when unprocessed products were used as organic mulches, but this inhibitory effect disappeared when unprocessed dry olive cakes were previously vermicomposted. Phosphatase activity was stimulated by the presence of organic mulches, especially if they were previously vermicomposted. Dry olive cake should be vermicomposted prior to use as mulching media in horticultural crops.

Steam‐explosion pretreatment of olive cake

AbstractOlive cake was processed by steam‐explosion under different steam conditions, followed by fractionation to separate the main components. In the water‐soluble fraction, the main compounds were carbohydrates. Glucose represented a significant part of the total monosaccharide content, especially under conditions of mild severity, followed by arabinose, but the solubilization of sugars occurred predominantly in the oligomeric fraction. Mannitol was also found in significant amounts (1.5%), similar to that in the initial material. In the ethyl acetate extract, low molecular weight phenols were identified, the most aboundant being hydroxytyrosol, which is present in the olive pulp. Hydroxytyrosol is abundant and has great antioxidant activity, reaching 149 mg/100 g of dry olive cake. The procedure used in this study obtained all the hydroxytyrosol residual present in the by‐product. The constitutive polymers were quantified in the insoluble fraction, and the sugar composition showed that cellulose was associated with a high proportion of xylans and other polysaccharides rich in arabinose and galactose. This cellulose was nearly amorphous, as it was highly susceptible to hydrolytic enzymes. The extractables in dilute alkali (not true lignins) increased as steaming became more severe; the residual “lignin” in this fraction decreased. Enzymatic hydrolysis of the insoluble fraction using a cellulolytic complex was also studied. The slight increase in the extent of saccharification was not proportional to the high alkaline delignification. However, when the residues were efficiently delignified with chlorite treatment, the susceptibility to enzymatic hydrolysis greatly increased.

Growth and reproduction of Eisenia andrei in dry olive cake mixed with other organic wastes

Growth and reproduction of Eisenia andrei in dry olive cake mixed with other organic wastes