Technical Bulletin A New Efficient Talc for Olive Oil Extraction

Transcription

1 Technical Bulletin 1601 A New Efficient Talc for Olive Oil Extraction _NEU_TB1601_07_all_Klapper_ :23:16 Uhr

2 Contents Summary 2 Introduction 3 Materials and methods 3 Results 4 Conclusions 7 References 7 Summary The performance of two different talc grades in olive oil extraction was investigated. The talc grades used were one that is commonly used by the olive oil industry (Talc 1) and a new product from Mondo Minerals specially developed for olive oil production: Micro-Talc FC 8. The olives were collected from two different areas in southern Spain: Picual and Hojiblanca. The olives were harvested at four different stages of ripening (2006/2007). The olive oil extraction tests were carried out according to the Abencor system at 25 C. The results showed that the addition of talc improved the oil yield. They showed also that Micro-Talc FC 8 gave higher oil yields than the other talc, even though its addition rate was only 0.3 % wt. compared to 1.0 % of the other talc, based on the weight of the olives. The quality of the oil was also better when Mondo Minerals talc was used. The degree of acidity, peroxide and UV extinction values were better with it compared with those obtained using the other talc grade. The quality of olive oils obtained could be classified as Extra Virgin Olive Oil according to the EU Commission Regulations (EC) No 1989/2003. The performance of Micro-Talc FC 8 was superior to the talc grade normally used for olive oil production. The excellent efficiency of the Mondo Minerals talc was due to its high purity (greater oleophilicity) and very fine particle size (high active surface area). This study showed that Mondo Minerals new talc grade, Micro-Talc FC 8, is an excellent aid for the olive oil extraction process. Additionally, reduction of the dosage by 70% results in lower handling costs. Introduction Virgin olive oil is normally obtained by a mechanical process at temperatures that do not lower the quality of the oil. After harvesting, the olives are transported to the processing plant. There they are washed, crushed and then milled to a so-called olive paste. Water is then added to the paste and the solid material is separated from the oil and water by a centrifuging. The oil and water are then allowed to settle so that the olive oil layer can be decanted off and bottled. Sometimes the separation of solids from the oil and water is difficult. The separation problem is faced when so called difficult olives are processed. This sort of olives is normally collected either at the beginning or at the end of the season when the olives contain either too little or too much water. Bad weather conditions during ripening increases the amount of difficult olives. The difficult olives produce a lot of extra foam during the paste preparation and causes an excess of a fine solids that acts as a natural emulsifier for the oil droplets in water. These natural emulsifiers retain some of the oil droplets in the water phase and so reduce the amount of oil that can be extracted. One very extensively used substance that solves the extraction problems of difficult olives is talc. Talc is a natural mineral that has an oleophilic surface and a platy particle shape. When a small quantity of talc is addedto the olive paste, it adsorbs the natural emulsifiers from the surface of the olive oil droplets and so increases the amount of oil that can be extracted. The talc s plates bring the small oil droplets together to create bigger droplets that are easier to separate by centrifuging, which again increases the oil yield. Talc is a chemically inert mineral, so it does not affect the intrinsic properties of the paste or the characteristics of the resulting oil. _NEU_TB1601_07_all_Klapper_ :23:16 Uhr

3 Because the talc is a natural product, its quality varies depending on the deposit and the production location. Each talc mine has its own characteristics and that is why talc grades differ in their performance in the end applications. The objective of this study was to compare the performance of two different talc grades in olive oil extraction. The talc grades tested were: Talc 1 - a talc grade produced in Spain, that is commonly used in olive oil extraction. Talc 2 - a new talc grade for the olive oil market produced by Mondo Minerals, the trade name of the product is Micro-Talc FC 8. Batch process with 3-phase decanter Leaf removal Hammer mill Delivery Washing machine Batch malaxer 3-phase decanter Separator Continuous process with 2-phase separating decanter Graph 1: Three phase and two phase olive oil extraction process. Silo Malaxer 2-phase separating decanter Separator Storage Hammer mill Source: Westfalia Separator AG Materials and Methods Olives The olives from two different production areas in southern Spain were collected. The areas were Picual near to Jaen and Hojiblanca near to Baeza. Olives at four different stages of ripeness were collected at about 20 day intervals, from the beginning of December 2006 until the last two weeks of February Each sample consisted of 5 kg of olives. The following properties were measured on each olive sample: ripeness index, moisture and volatile matter content, oil content on wet and dryweight basis. 3 _NEU_TB1601_07_all_Klapper_ :23:28 Uhr

4 Talc Grades The characteristics of the talc grades used are presented on the table 1. Micro-Talc FC 8 is produced by Mondo Minerals using a process that is certified for the production of talc grades for food stuff applications. The major differences between the talc grades used were in the mineralogical composition and particle size: Mondo Minerals talc clearly has a higher talc content and its particle size is finer. Extraction Process The extraction of olive oil was carried out using the Abencor system. After crushing the olives in a hammer mill and mixing them into a homogeneous pulp, a sample was taken. The moisture content, volatiles (HMV%) and the oil content by Soxhlet method, were determined. The rest of the milled sample was divided into five portions 1 % wt of Talc 1 was added to 2 samples and only 0.3 % wt of Talc 2 to the next 2. One sample was kept as a reference without the addition of talc 50 ml of water at 60 C was added to each of the talc containing samples. All the samples were mixed for 30 minutes at 30 C. After the mixing, they were centrifuged twice for 90 s at 3000 rpm. The liquid phases were decanted into 500 ml test tubes. The volume of olive oil was measured and the olive yield was calculated using the olive oil density of kg/m³. Olive Oil Analysis The following five properties were determined to ascertain the quality of the olive oil: degree of acidity (UNE 55011), peroxide value (UNE 55023), saponification value (UNE 55012) and UV extinction coefficients K270 and K232 in accordance with the European Union Commission Regulation (2003). Property Talc 1 Micro-Talc FC 8 Table 1: The Properties of the Talc Grades Used in the Olive Oil Extraction Study. Mineralogical composition Talc/Chlorite blend Pure Talc Talc content in % wt Average particle size in µm Specific surface area, m²/g Reflectance Ry in % Table 2: Properties of Olives from Two Different Harvest Areas. Area Harvesting Date Ripeness Index Moisture and Volatiles HMV % Oil Content in % on Wet Basis Oil Content in % on Dry Basis Picual Hojblanca Results Extraction process characteristics are showed on the Table 2. As one can seen from table 2, the olives collected from different areas had very different ripeness indices, even when the collection dates were close together. The oil content in the olives also varied a lot. The olives harvested in the Picual area had higher oil contents than those from Hojblanca. The efficiency of talc is presented in figures 1 and 2 where the oil yields of each extraction test is given. _NEU_TB1601_07_all_Klapper_ :23:30 Uhr

5 The results show that the addition of talc improves the oil yield in all cases. The addition of talc increased the oil yield more for the olives collected from the Picual area. Mondo Minerals talc, Micro-Talc FC 8, was more effective than the other talc. The difference in effectiveness between the talcs was biggest for Picual olives that were more difficult to extract than Hojblanca olives. This indicates that Micro-Talc FC 8 was clearly more effective than the Talc 1. Please note that only 0.3 % Micro-Talc FC 8 was added compared with 1% of Talc 1. Figure 1: Oil yield (Ra%) of Abencor extraction tests for two different talc types. The olives were harvested from Picual area. Figure 2: Oil yield (Ra%) of Abencor extraction tests for two different talc types. The olives were harvested from Hojiblanca area. 5 _NEU_TB1601_07_all_Klapper_ :23:32 Uhr

6 Oil Characterisation The olive oil obtained is characterised by the following parameters: degree of acidity (GA), peroxide value (IP), saponification value (IS) and UV extinction coefficients (K270 and K232). The tables 2 and 3 show the results for Picual and Hojiblanca. Tables 1 and 2 show that the quality of the oil is improved when talc is used in oil extraction. The results also show that the talc grade of Mondo Minerals, Micro-Talc FC 8, gives a lower acidity, lower peroxide values and finally lower UV extinction coefficients (K270 and K232) than Talc 1. The lower values of these quality parameters indicate that Micro-Talc FC 8 gives a better oil quality than the other talc used in this study. The saponification values were similar for both talc types. It is important to note that all the oil samples fulfil the quality requirements set for highest olive oil quality class: Extra Virgin Olive Oil. The olive oil quality ranking is set by the European Commission in the Regulation of (CE) No 1989/2003. Harvesting Date Parameter Without Talc Talc 1 Micro-Talc FC 8 Table 2: Olive Oil Quality Parameters Obtained by Abencor System for the Olives Harvested from the Picual Area Degree of Acidity Peroxide Value Saponification Value Extinction Coefficient K Extinction Coefficient K Degree of Acidity Peroxide Value Saponification Value Extinction Coefficient K Extinction Coefficient K Degree of Acidity Peroxide Value Saponification Value Extinction Coefficient K Extinction Coefficient K Degree of Acidity Peroxide Value Saponification Value Extinction Coefficient K Extinction Coefficient K _NEU_TB1601_07_all_Klapper_ :23:32 Uhr

7 Harvesting Date Parameter Without Talc Talc 1 Micro-Talc FC Degree of Acidity Peroxide Value Saponification Value Extinction Coefficient K Extinction Coefficient K Degree of Acidity Peroxide Value Saponification Value Extinction Coefficient K Extinction Coefficient K Degree of Acidity Peroxide Value Saponification Value Extinction Coefficient K Extinction Coefficient K Degree of Acidity Peroxide Value Saponification Value Extinction Coefficient K Extinction Coefficient K Table 3: Olive Oil Quality Parameters Obtained by Abencor System for the Olives Harvested from the Hojiblanca Area. Conclusions The purpose of this study was to investigate the efficiency of two different talc grades in olive oil extraction. The talc grades used were the talc grade that is commonly used by olive oil industry (Talc 1) and the new talc grade from Mondo Minerals specially developed for this application: Micro-Talc FC 8. The difference of Mondo Minerals talc to the commonly used one was that it is purer (more oleophilic) and its particle size was clearly finer (higher active surface area). The olives were collected from two different areas in southern Spain: Picual and Hojiblanca. The olives were harvested at four different stages of the ripening period (2006/2007). The performance of the talc grades was compared with one another by using the samples without talc addition as a reference. The olive oil extraction tests were carried out according to the Abencor test at the University of Jaen in Spain. The results showed that the talc improved the oil yield. They also showed that Mondo Minerals talc (Micro- Talc FC 8) gave higher oil yields than the other talc, even though only 0.3% wt of the Mondo Minerals talc was added whereas the addition rate of the other talc was 1.0 % wt on the weight of olives. The quality of the oil was also better when Mondo Minerals talc was used. The acidity, peroxide and UV extinction values were better with Mondo Minerals talc (Micro-Talc FC 8) than with the other talc grade. The quality of the olive oil can be classified as Extra Virgin Olive Oil according to the EU classification system for the olive oils, even if the so-called difficult olives were processed. This indicates that the pure, finely ground talc offers excellent benefits in olive oil manufacturing. References 1. Sebastian Sanchez, Rafael Pacheco, Ma Dolores La Rubica, Antonio Sanchez, Tomas Molina, Ma Gema Pereira, Javier Jusue: Comparative Study Between Two Natural Microtalcs Used as Technical Coadjuvants in the Virgin Olive Oils Extraction, Department of Chemical, Environmental and Materials Engineering, University of Jaen, The Commission of the European Communities: Commission Regulation (EC) No 1989/2003 on the Characteristics of Olive Oil and Olive-pomace oil and on the relevant methods of analysis, 6th November _NEU_TB1601_07_all_Klapper_ :23:33 Uhr

8 MONDO MINERALS OY. Kasarmikatu 22. FI Helsinki. Phone Fax The information contained in this Technical Bulletin relates only to the specific tests designated herein and does not relate to the use of products in combination with any other material or in any process. The information provided herein is based on technical data that Mondo Minerals believes to be reliable, however Mondo Minerals makes no representation or warranty as to the completeness or accuracy thereof and Mondo Minerals assumes no liability resulting from its use for any claims, losses, or damages of any third party. Recipients using this information must exercise their own judgement as to the appropriateness of its use, and it is the user s responsibility to assess the materials suitability (including safety) for a particular purpose prior to such use. _NEU_TB1601_07_all_Klapper_ :23:33 Uhr