Olive pomace products, method of production and their uses

Abstract

The present disclosure relates to olive pomace and a green methodology to obtain derivative products for it valorization. The obtained products may be used as a solid substrate, nutraceuticals, cosmetics or food supplements.

Claims

1. An olive pomace or an olive pomace solid substrate, comprising: up to 1% (m/m) of olive fat material; and up to 0.06% (m/m) of phytotoxic compounds.

2. The olive pomace or olive pomace solid substrate of claim 1, comprising up to 0.5% (m/m) of the olive fat material.

3. The olive pomace or olive pomace solid substrate of claim 1, comprising up to 0.02% (m/m) of the phytotoxic compounds.

4. The olive pomace or olive pomace solid substrate of claim 1, wherein the phytotoxic compounds are phenolic compounds.

5. The olive pomace or olive pomace solid substrate of claim 1, wherein the phenolic compound is selected from the group consisting of: aglyconic and glycosidic forms in particular, hydroxytyrosol, tyrosol, oleuropein, verbascoside, elenolic acid, catechol, rutin and mixtures thereof.

6. An africultural additive, comprising the olive pomace or olive pomace solid substrate of claim 1.

7. The agricultural additive of claim 6, wherein the agricultural additive has a germination index of at least 85%.

8. The agricultural additive of claim 6, wherein the agricultural additive has a pH of 4.8-5.8.

9. The agricultural additive of claim 8, wherein the agricultural additive has a pH of 5.1-5.8.

10. The agricultural additive of claim 6, wherein the agricultural additive comprises at most 170 mg gallic acid equivalents/100 g of wet weight of olive pomace.

11. The agricultural additive of claim 10, wherein the agricultural additive comprises 20-60 mg gallic acid equivalents/100 g of wet weight of olive pomace.

12. The agricultural additive of claim 6, wherein the agricultural additive is a soil fertilizer, a soil substrate additive, an agricultural irrigation additive, or a soilless culture additive.

13. A method for obtaining an olive pomace solid substrate of claim 1 and an extract, comprising: extracting of an olive fat from an olive pomace; adding water to the olive pomace in a 1:15-1:80 mass of olive pomace: volume of water ratio to form a first solution; stirring the first solution at 600 rpm for 10-90 minutes until a temperature of 405 C. is reached; stirring the first solution at 600 rpm for 10-90 minutes after the temperature of 405 C. is reached; filtrating the stirred first solution to collect an olive pomace solid phase and an olive pomace aqueous extract; adding water to the collected olive pomace solid phase in a 1:15-1:80 mass of olive pomace solid phase:volume of water ratio to forma second solution; stirring the second solution at 600 rpm for 10-90 minutes, until a temperature of the 40 C.5 C.; stirring the second solution at 600 rpm for 10-90 minutes, after the temperature of the 405 C. is reached; filtrating the stirred second solution to collect a final olive pomace solid phase and a final olive pomace aqueous extract; collecting the final olive pomace solid phase and the final olive pomace aqueous extract.

14. The method of claim 13, wherein the step of adding water to the olive pomace or to the pomace solid phase is performed in a ratio of 1:40-1:50.

15. The method of claim 13, further comprising: drying the final olive pomace solid phase for 60 minutes at 60 C. until 5% (m/m) moisture is reached.

16. The method of claim 13 wherein the steps of adding water, stirring, filtrating and collecting and drying are repeated using olive pomace.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The following figures provide preferred embodiments for the present disclosure and should not be seen as limiting the scope of the disclosure.

(2) FIG. 1: Flow diagram of the olive pomace processing. ROPraw olive pomace; DOPDefatted olive pomace; OPolive pomace.

(3) FIG. 2: Chromatogram of major phenolic compounds present in olive pomace aqueous extracts.

(4) FIG. 3: Antioxidant activity (FRAP and DPPH* inhibition) of olive pomace aqueous extract and pure hydroxytyrosol. FRAPferric reducing antioxidant power; DPPH*, (2, 2-diphenyl-1-picrylhydrazyl).

(5) FIG. 4: Moisture content along the raw olive pomace processing (%). ROPraw olive pomace; OPolive pomace.

(6) FIG. 5: DOP total phenolics, expressed in mg gallic acid equivalents (GAE), per 100 g of olive pomace after first and second cycle of extraction.

(7) FIG. 6: Germinated seeds (Lepidum sativum) (1-GI=3%; 2-GI=92%).

(8) FIG. 7: Preliminary first growing trial with green pea seeds (Pisum sativum) (C-GI=3%); D-Control; F-GI=92%).

DETAILED DESCRIPTION

(9) Olive pomace sustainable processing intends to develop olive pomace-derived ingredients and products including an olive fat-based mixture, a bioactive rich extract and a solid substrate for agricultural applications as soilless culture.

(10) FIG. 1 describes an embodiment of the present disclosure, in particular an embodiment of the process now disclosed.

(11) In an embodiment, olive pomace is reprocessed repeating the phases of malaxation and centrifugation. Then, the olive pomace is pressed. Three different phases are obtained: an oil phase, an aqueous phase, and the defatted olive pomace.

(12) In an embodiment, after recovering the olive pomace fat, an extracting process for olive pomace defatted treatment is applied. It is added water to the olive pomace, in particular 1.875 g of olive pomace to 75-150 mL of water (1:40-1:80) (mass of olive pomace solid phase:volume of water). The solution is continuously stirred between 600 and 900 rpm in a heating plate (MS-H-S10 10-Channel Classic Magnetic Hotplate Stirrer) until reaching 405 C. during 60-90 minutes, preferably for another 60 minutes. This procedure must be continued, in particular for another 60-90 minutes (steps 2 and 3), preferably for another 60 minutes. The obtained solution is filtered (step 4) using a Whatman qualitative filter paper, Grade 4.

(13) Therefore, two different products are obtained after the filtration step, in particular an aqueous extract rich in phenolic compounds (step 5) (OP aqueous extract 1 and OP aqueous extract 2) and the solid phase (OP solid phase) (step 6).

(14) In an embodiment, the above-mentioned steps 2, 3, 4 may be repeated with the OP solid phase previously obtained. Therefore, a continuous cyclic process may be carried out and the extraction process is repeated as previously described (step 7). It is obtained a second olive pomace aqueous extract (OP aqueous extract 2) and a second olive pomace solid phase (OP solid phase 2).

(15) In an embodiment, the OP solid phase is collected and dried in a ventilated oven, in particular for 60 to 90 minutes at 55-65 C. until a moisture content of 5-15% (m/m), preferably 5-6% (m/m)(step 8). Thus, it is obtained the OP solid substrate.

(16) In an embodiment, the substrate can be considered as non-toxic when the germination index is higher than 80%, preferably 85%. The phytotoxicity of the OP solid substrate was evaluated using the Germination Index (GI) according to well established scientific references (Rusan M J, Albalasmeh A A, Zuraiqi S, and Bashabsheh M. Evaluation of Phytotoxicity Effect of Olive Mill Wastewater Treated by Different Technologies on Seed Germination of Barley (Hordeum Vulgare L.). Environmental Science Pollution Research. 2015;12:9127-35; Selim S M, Mona S Z, and Houssam M A. Evaluation of phytotoxicity of compost during composting process. Nature and Science. 2012;10(2):69-77).

(17) In an embodiment, twenty cress (Lepidium sativum) seeds were put to germinate in an aqueous solution obtained from OP solid substrate (in particular 1 g of OP solid substrate in 10 mL of deionized water). Then the seeds were put to germinate at room temperature, in the dark, for 72 hours. The germination just in deionized water was considered as control. After the incubation period, both germination and root length were evaluated to determine GI.

(18) In an embodiment, the total phenolic compounds evaluation was conducted by a spectrophotometric method as already described above (Alves R C, Costa A S, Jerez M, Casal S, Sineiro J, Nunez M J and Oliveira MBPP. Antiradical activity, phenolics profile, and hydroxymethylfurfural in espresso coffee: influence of technological factors. Journal of Agricultural and FoodChemistry. 201;(58): 12221-12229).

(19) In an embodiment, in order to study the optimal extraction conditions, in particular based on the green chemistry, different procedures with deionized water were tested in a laboratory scale varying extraction time, in particular 60 minutes, 120 minutes, and two cycles of 60 minutes and temperature, in particular at room temperature and 40 C. It were also tested different mass/volume (m/v) ratios olive pomace:water, in particular 1:10; 1:15; 1:20; 1:40; 1:50; 1:60; 1:70; 1:80. The solutions (water and olive pomace) were continuously stirred between 600 and 900 rpm (MS-H-S1010-Channel Classic Magnetic Hotplate Stirrer). After that, the solutions were filtered using a Whatman qualitative filter paper, Grade 4. The OP solid phase was collected and dried in a ventilated oven, in particular for 60 to 90 minutes at 55-65 C. until a moisture content of 5-6% (m/m). This last product is named OP solid substrate. The GI assay of OP solid substrate was performed as already described.

(20) In an embodiment, at room temperature, 60 minutes of extraction, 100% water as solvent and a ratio 1:10 (m/v) allow to obtain the lowest GI (29%). In this OP solid substrate, remained 170 mg EAG of phenolic compounds. At room temperature and using a 1:15 ratio, in the OP substrate still remains 170 mg EAG showing that the maximal extraction levels were achieved.

(21) In an embodiment, a GI of 72% was obtained with a ratio of 1:40, at 40 C. In this case, the OP solid substrate total phenolics content was 86 mg EAG. Despite using the same ratio and temperature, an increase in GI (78%) was observed when the extraction time was increased from 60 to 120 minutes and a decrease in total phenolics, in particular 76 mg EAG, was verified.

(22) In an embodiment, results showed a decrease in total phenolic compounds and an increase in the GI and pH.

(23) In an embodiment, the OP solid substrate obtained after all proposed extraction steps, as listed in technical design, has 53 mg GAE/100 g. The initial olive pomace (defatted olive pomace) total phenolic content is significantly higher (635 mg EAG/100 g of defatted olive pomace) than the OP solid substrate achieved.

(24) The described features of the OP substrate allowed considering it not an environmental hazard due to the absence of the initial phytotoxicity (GI=92%).

(25) In an embodiment, after the first extraction cycle it was obtained an olive pomace which contains 865 mg EAG/100 g of olive pomace and a after a second it contains 139 mg EAG/100 g of olive pomace.

(26) In an embodiment, the pH values increased along the process from 4.8 for the defatted olive pomace to 5.8 for the OP solid substrate with beneficial effects to plants' growth, as FIGS. 6 and 7 show.

(27) In an embodiment, defatted olive pomace presented a 3% GI but the OP solid substrate obtained after the procedure disclosed in table 1 presented a 92% GI.

(28) In an embodiment, the OP solid substrate was submitted to a preliminary first growing trial with green pea seeds (Pisum sativum). Pea seeds were soaked and put to germinate in OP solid substrates (GI=3, 78 and 92%). Results showed the plant germination and growth in two experiments 78% (E) and 92% (F), meaning absence of toxicity (FIG. 7).

(29) TABLE-US-00001 TABLE 1 Germination Index (GI) and pH of OP solid substrate and defatted olive pomace. GI (%) pH OP solid substrate 92 4 5.8 2.0 Defatted olive pomace 3 0.2 4.8 0.1

(30) In an embodiment, the fat that remains in olive pomace is extracted, in particular without using chemical solvents (step 1) and used as a base ingredient for an olive oil-based mixture.

(31) In an embodiment, the defatted remaining product was submitted to an aqueous extraction at controlled time and temperature to recover the bioactive compoundsOP aqueous extracts (steps 2, 3, 4, 5). After that, these will be retained in a device and further submitted to different treatments aiming to valorise its known benefits to human health and well-being. The solid end product (OP solid substrate) is suitable for agricultural applications due to its low phytotoxicity (step 8).

(32) The products obtained have high economic value, reduced production costs, and minimal environmental load.

(33) The present disclosure relates to a process for obtaining added-value products from olive pomace wherein said process comprises the following sequential steps: a. extracting of the remaining olive fat and water by repeating the phases of malaxation and centrifugation followed by the olive pomace pressing in order to separate liquid and solid phases; b. adding of water to defatted olive pomace to obtain a solution, in a 1:15-1:80 ratio, in particular in a 1:40 ratio (m/v), stirring at 600-900 rpm, in particular at 600 rpm during 60-90 minutes in particular 60 minutes, until 40 C., maintaining the same conditions during more 60-90 minutes, in particular 60 minutes; c. filtrating of the solution; d. step b) is repeated using the solid phase obtained in step c); e. filtrating of the solution; f. the solid phase is collected; g. drying for 60 minutes at 60 C., in particular in a ventilated oven till a moisture of 5-15%.

(34) In an embodiment, the products obtainable by the process above-mentioned is an olive fat-based mixture, OP aqueous extracts and an OP solid substrate.

(35) In an embodiment, the OP aqueous extracts are rich in bioactive compounds comprising a high content of phenolic compounds, namely hydroxytyrosol, comselogosid, tyrosol, or their mixtures is also obtained.

(36) TABLE-US-00002 TABLE 2 Total phenolics, expressed in milligrams of gallic acid equivalents (GAE) per 100 g of olive pomace. ROP OP solid substrate After first cycle of extraction 568 13 63 4 After second cycle of extraction 54 6 27 4 Total phenolics 622 89 ROPraw olive pomace; OPolive pomace.

(37) In an embodiment, it was determined the antioxidant activity of olive pomace aqueous extract to pure hydroxytyrosol. The reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been associated to the pathogenesis of several diseases such as cardio and neurovascular diseases, diabetes mellitus, and certain types of cancer. Phenolic compounds can act as antioxidants in several ways preventing the oxidative stress due to ROS and RNS (Aguilera Y, Martin-Cabrejas M A and Mejia E G. Phenolic compounds in fruits and beverages consumed as part of the Mediterranean diet: their role in prevention of chronic diseases. Phytochemistry Reviews. 2016; 15(3): 405-423).

(38) In an embodiment, FRAP (ferric reducing antioxidant power) and DPPH* (2, 2-diphenyl-1-picrylhydrazyl) inhibition are two regularly used in vitro assays to evaluate the antioxidant activity of extracts/compounds. They are complementary. In the DPPH* scavenging assay, the radical can be neutralized by direct reduction (via electron transfer) or by radical quenching (via H atom transfer). It is considered an advantageous method for screening the antioxidant capacity of both complex mixtures and pure compounds. The FRAP assay measures the ability of antioxidants to reduce the complex Fe.sup.3+-TPTZ to the coloured ferrous complex Fe.sup.2+-TPTZ in acidic medium. FRAP assay detects natural compounds with redox potentials but not compounds that act by radical quenching (H transfer), like DPPH*, since only an electron transfer mechanism occurs (Magalhes L M, Segundo M A, Reis S and Lima J L. Methodological aspects about in vitro evaluation of antioxidant properties. Analytica Chimica Acta. 2008; 613: 1-19).

(39) In olives, the most abundant phenolic compounds are 3, 4-dihydroxyphenyl-ethanol, or hydroxytyrosol, and p-hydroxyphenyl-ethanol, or tyrosol. Both compounds are soluble in water. Therefore, they are mostly present in olive pomace. Hydroxytyrosol has been described as the natural phenolic compound with higher radical scavenging potential with effective antioxidant properties (Rodin P S, Karathanos V T and Mantzavinou A. Partitioning of Olive Oil Antioxidants between Oil and Water Phases. Journal of Agricultural and Food Chemistry. 2002; 50(3): 596-601).

(40) The extract rich in bioactive compounds obtained by the method herein described comprises hydroxytyrosol, tyrosol, comselogoside, and other compounds (FIG. 2). Acting together they can have major antioxidant activity by a synergistic effect. Comparing the antioxidant activity of the olive pomace aqueous extract to a pure hydroxytyrosol standard, the natural extract presents higher antioxidant activity evaluated by FRAP assay (24 and 9 mol/mL, respectively). Furthermore, there are no significant differences in the antioxidant activity between the pure compound and the extract, considering the % of inhibition of DPPH* (FIG. 3).

(41) In an embodiment, the OP solid substrate may be used for agricultural applications as soilless culture and comprises a low content in phenolic compounds and high germination index.

(42) The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof.

(43) The above described embodiments are combinable. The following claims further set out particular embodiments of the disclosure.