Production Method of Alcohol-Free Pistachio Extract by Supercritical Extraction

Technical Field

The present invention relates to production of a pistachio extract by supercritical extraction method from roasted pistachio fruit to be used in the food and beverages sector, especially as a pistachio food additive.

Specifically, the invention relates to the pistachio extract produced by extraction treatment of roasted pistachio for 50-150 minutes in a supercritical extractor under 345- 400 bar pressure, 60-70 ^e C temperature and 75-100 g/min supercritical carbon dioxide flow rate, and the production method of the mentioned extract.

State of the Art

The object of extraction of foodstuff is to obtain separately certain components in the food to be extracted, in a sense to separate out an essential constituent of the food. Extracts are generally produced by solid-liquid extraction method. However, in extracts produced in this way, there may occur decomposition and deterioration due to temperature, costs increase due to the solvents used, and difficulties are experienced in meeting the EU requirement concerning solvent residues. Again for the same reason, most of the organic solvents cannot be used. The reasons for this is that they cause corrosion problems and may cause explosions. In addition, although the solvents used are removed away from the medium by concentrating them, the remaining residues make their use undesirable because of health considerations.

Currently, there is a continuing search for new technical and alternative solvents to increase operation capacity in extraction processes, to reduce costs, to get rapid ad high yield, etc. Most of the organic and inorganic solvents used in solid-liquid and liquid-liquid extractions are corrosive, toxic to humans, harmful for the environment and expensive and they also have many other undesired properties.

In current techniques, there are pistachio extracts produced with such methods. However, the extracts produced with these methods, in addition to the disadvantages mentioned above, have shelf lives of at least 6 months and at most 12 months. A disadvantage of the pistachio extract produced with current techniques is that they make use of alcohol. This is contrary to the halal product demand besides the disadvantages of alcohol. Consequently, because of the adversities mentioned above and the inadequacy of the existing solutions, an advancement in the pistachio extract production method which does not contain alcohol is deemed necessary.

Object of the Invention

The present invention relates to a production method for producing alcohol-free pistachio extract, where the supercritical extraction method is used, which meets the above needs, which eliminates all disadvantages and which brings some additional advantages. The first object of the invention is to extract a product in which the nutritional value and organoleptic properties of pistachio fruit is preserved and which does not contain alcohol.

An object of the invention is to use adding supercritical carbon dioxide added at low temperature to preserve the above mentioned organoleptic properties and at the same time to preserve the antioxidant property of the pistachio extract produced with this method.

A similar object of the invention is to render a superior aspect to the other extracts since ethyl alcohol, still not desired in halal production, is not used.

Another object of the invention is that the pistachio extract is rich in phenolic substances and unsaturated fatty acids. A further object of the invention is to be able to extract at a low temperature and under an inert medium, without chemical or thermal change.

A similar object of the present invention is that the solubilities of the extracts obtained are higher than those obtained using the methods of the already existing techniques. Another further object of the present invention is to be able obtain the pistachio without loss in virtue of the high vapour pressure of carbon dioxide and besides this, not to extract undesired components such as proteins and sugars. Still another object of the invention is that the extracts produced using C0 ₂ -supercritical extraction, in virtue of economy in time and solvent, provide reduction in cost compared to those made using solvent.

A similar object of the invention is that it has a shelf-life of 24 months.

An even further object of the invention is to produce a pistachio extract, the changes of which when roasted differently are determined, which is different from the other pistachio extracts in the market and which is favourable for the Turkish gusto. Another object of the invention is using roasted pistachio.

In order to realize the objectives described above, a pistachio extract production method from pistachio fruit is provided, which method is characterized by consisting of the following process steps: a) roasting the pistachio fruit,

b) extracting the roasted pistachios, with the addition of ethyl alcohol for 50-150 minutes in a supercritical extractor under 345-400 bar pressure, at 60-70 ^e C temperature and under 75-100 g/min supercritical carbon dioxide flow rate.

The structural features and characteristics and all advantages of the present invention will be more clearly understood by the detailed disclosure given below, and hence, the assessment should be made taking into account this detailed disclosure.

Detailed Description of the Invention

In this detailed description, the subject of which is the preferred embodiments of the alcohol-free pistachio extract production method using the supercritical extraction method and are disclosed only for helping to better understanding the subject and are not limiting in anyway. The invention relates to pistachio extract production from roasted pistachio fruit by the supercritical extraction method, to be used in the food and beverage industry, especially in pistachio aromatizers, in cakes and biscuits as chocolate filling, in ice creams and in ice cream sauces, in ready to drink coffee and milk products.

Supercritical extraction method:

Normally, liquid and gas are two different states, they have different properties such as density and dispensability. However, when the temperature and pressure rise above a certain value, it becomes hard to define the properties of liquid and gas. At the liquid- gas phase boundary, a stop is observed at certain temperature and pressure. This is the critical point. Above this point is the critical region. By increasing the pressure isothermally or by increasing the temperature isobarically, a fluid is obtained. The fluids formed above this point are a combination of liquid and gas and are called supercritical fluids (1 , 2). The critical point is the temperature and pressure at which the liquid and gas phases are indistinguishable. The lines that separate the liquid, gas and solid phases are phase boundaries. These boundaries meet at the triple point. The matter above the critical temperature and critical pressure pass onto a fourth phase in a combination of the properties of the liquid and gas.

The supercritical fluid extraction can be expressed as dissolving a substance in a supercritical fluid, or example in carbon dioxide and then separating it from the product fluid by decreasing it isobarically or isothermally. A supercritical fluid is a substance in which there is no apparent liquid or gaseous phase and which has a temperature and pressure above the critical point. It can disperse in solids like gas and can dissolve substances like a liquid. Processing food and biological substances with supercritical fluids, is an important tool in obtaining functional and high-value products.

Features:

• They have properties in-between a gas and a liquid. Their densities are similar to that of liquids and they act like a liquid solvent. They have good diffusion properties that render low viscosity and mass transfer characteristics.

· Their high relative densities give them good solvent properties.

• Their latent heats of evaporation are zero, thus, their hear capacities are very high. • The energy requirement of the system is low. Their surface tension coefficients and viscosities, λ, are low, and hence their pumping costs are low.

One of the most frequently used supercritical fluids is carbon dioxide. Some of the reasons for this are as follows:

• It is inert,

• It is not corrosive in dry media,

• It is not combustible nor explosive,

• It is not harmful to food and environment,

· It has high mass transfer capacity,

• It is multi-functional.

Supercritical fluid extraction has some advantages over the conventional extraction methods (3). These are as follows:

1 . Supercritical fluids have higher diffusion coefficients and viscosities compared to that of liquids.

2. The fact that they do not have surface tension ensures that they penetrate into the pores of heterogeneous matter more rapidly and thus, that the efficiency of extraction is higher.

3. The selectivity of extraction increases with controlled changes in temperature and pressure, affecting the solubility of different components.

4. There is no chemical residue left after extraction.

5. In extraction, recoverable gases that can be re-used, such as carbon dioxide, can be utilized.

Carbon dioxide exhibits supercritical fluid characteristics when its temperature and pressure reaches or exceeds the 31 Ό and 74 bar val ues, which marks the critical point. The reason why carbon dioxide is extensively used originates from its low toxicity, chemical inertness, its being economical and easy to use.

The characteristics of the pistachio extract obtained by the supercritical extraction method are that it has preserved its organoleptic properties, it can be used directly in aromatisers and/or in food, and it has the taste and flavour of pistachio. Process formulation of the pistachio extract:

In the present invention supercritical carbon dioxide must be used as solvent and carrier and the said pistachios must be roasted between 100 and180 Ό.

In this invention, especially roasted pistachio is used. When the pistachio is roasted, various reactions take place between the fatty acids and carbohydrates it contains. This renders a unique aroma to the pistachio. Production Method for Pistachio Extract

Extraction in a supercritical extractor is used in the extraction method.

• The pistachio fruit is roasted until it reaches the desired taste and is placed in the chamber in the extractor,

(In supercritical extraction, 345-400 bar pressure; 60-70 ^e C temperature; 75-100 g/min, supercritical carbon dioxide flow rate. In addition, the amount of matter to be used must be 200-250 gr and the size of the particles must be 25-50 microns.

• The roasted pistachio is subjected extraction for 50-150 minutes and

• The extract obtained after this period is the pistachio extract,

The raw materials that the pistachio extract contains:

Raw material Preferred auantitv, bv weiaht (%)

Pistachio Extract (obtained from 100

pistachios roasted at 100-180 ^< C) REFERENCES

1. Dogan 2009 2. Yilmaztekin, Erten ve Cabaroglu, 2005

3. Rozzi ve Sing, 2002

4. Alasalvar C. ve Ark. 2003; Pfnuer P. ve Ark. 1999