INTERMEDIATE MOISTURE FRUITS AND FRUIT PRODUCTS FROM

DRIED FRUTS

Technical Field

This invention is related to a method to obtain intermediate moisture fruits and fruit products from dried fruits.

More specifically this invention is related to a method that uses dried fruits to produce intermediate moisture fruits and fruit products enriched with polyphenol compounds having potential health benefits. This invention was conducted at the field of food science and technology and aimed development of functional food products.

Prior Art Before supplied in market, the sun dried fruits are frequently immersed into water or aqueous solutions containing different preservatives and additives. This process is called rehydration and it is generally applied to bring the moisture level of dried fruits from between 17 and 19 % to between 22 and 40 %. The major purpose of commercial rehydration that is applied before marketing is to increase the moisture content of dry fruits, hence, to turn their hardly chewable firm texture to an easily chewable gummy one.

During rehydration most producers added some preservatives into the rehydration solutions and try to prevent microbiological spoilage of the final intermediate moisture fruits and fruit products during their storage at room or chilled temperatures. In some cases the pasteurization is also employed to the final intermediate moisture fruits to eliminate use of preservatives.

The aim of the rehydration process applied in this invention is different from that currently applied in some western counties by immersing dried fruits into wine and fruit juices. The currently applied process conducted at small scale mostly at homes by immersion of dried fruits into wine, fruit juices and alternative beverages aims modification of the taste, flavor and texture of dried fruits. During the well-known currently applied rehydration process conducted in wine, fruit juices and beverages the rehydration kinetics of the fruits is not considered and the final moisture content of the fruits are set randomly according to the personal preferences. No food additives are also used during this empirical rehydration and no thermal processing is applied to increase the shelf-life of the final intermediate moisture fruit products since they are consumed within a short time period. A more important truth is that this well-known currently applied process never aims the increase of total polyphenol content of the final rehydrated intermediate moisture fruits, and it never includes any particular process for the considerable increase of total polyphenol content of the final rehydrated intermediate moisture fruits. In fact, the well-known currently applied rehydration process can not be applied as an effective tool to increase the total polyphenol content of rehydrated fruits above a certain level due to the limited polyphenol content of wines and fruit juices. The method applied in this invention is also considerably different than that specified in the Japanese patent with no JP2005295831 which also aims production polyphenol enriched fruit products. The method specified in the Japanese patent with no JP2005295831 uses fresh fruit pieces as a starting material and it obtains polyphenol enriched dried fruit pieces at the size of maximum 5mm and at 20% moisture content. Although the Japanese patent with no JP2005295831 aims production of polyphenol enriched fruits, it applies considerably different processes than those in this invention and it obtains final fruit products with considerably different appearance and texture suitable for different commercial purposes. One of the major differences of the Japanese patent with no JP2005295831 than this invention is that its starting material is pieces of fresh fruits and it obtains polyphenol enriched fruit pieces at the maximum size of 5mm and at the moisture content of 20%.

In this invention the starting material is whole dry fruits, and the final products are whole polyphenol enriched fruits at 22% to 50% moisture content, or pieces (at desired size) of polyphenol enriched fruits obtained from whole fruits at 22% to 50% moisture content, or polyphenol enriched fruit puree obtained from whole fruits at 22% to 50% moisture content.

In this invention the polyphenol enriched whole fruits or fruit pieces at 22% to 50% moisture are softer, more chewable and gummier than those pieces of polyphenol enriched fruits at 20% moisture content specified in the Japanese patent with no JP2005295831. Moreover, the method described in the Japanese patent with no JP2005295831 is developed only for using pieces of fresh fruits as starting material and it obtains pieces of polyphenol enriched dry fruit pieces as the final product while this invention is developed for whole dried fruits and it obtains whole intermediate moisture polyphenol enriched fruits, fruit pieces or puree as final products.

In the Japanese patent with no JP2005295831 the production of polyphenol enriched fruit pieces having a stable commercial shelf-life needs bringing of their moisture level to 20% by use of an expensive drying method called lyophilization. In contrast, in this invention the obtained final product was not dried again and a stable commercial shelf-life is achieved between 22% and 50% moisture content by using low cost food additives, or combinational use of food additives and chilling, or use of pasteurization. Another difference of the method in the Japanese patent with no JP2005295831 than the method in this invention is that the method in the specified Japanese patent involves incubation of fresh fruit pieces in polyphenol rich solutions under vacuum. In the method described in JP2005295831 the incorporation of phenolic compounds in the solution into pieces of fresh fruits is not possible without the application of vacuum. In contrast, in this invention the incorporation of phenolic compounds into dry fruits is achieved at atmospheric conditions (without using vacuum) during rehydration process which progresses spontaneously by absorption of polyphenol compound solution by the dry fruits.

All these discussions clearly show the differences between the method described this invention and the method specified in the Japanese patent with no JP2005295831. Brief Description of the invention

The aim of this invention is to modify and to exploit the classical dry fruit rehydration process as a tool to obtain functional foods with increased health benefits.

Another aim of this invention is to exploit the classical rehydration process, targets softening of hardly chewable firm sun dried fruits by increasing their moisture content, for incorporation of polyphenol compounds having health benefits into rehydrated fruits. By dissolving polyphenol compounds in rehydration medium and enabling their incorporation into rehydrated fruits, the classical rehydration process will turn to a method to produce polyphenol enriched intermediate moisture fruit and fruit products.

Instead of using the classical rehydration process that is applied mainly to improve (soften) the texture of sun-dried fruits by immersing them into water or solutions containing food additives, this invention aims a considerable increase of polyphenol content of sun-dried fruits by rehydrating them in polyphenol rich extracts, polyphenol rich fruit juice concentrates, and polyphenol rich concentrated tea infusions. This invention provides a new method to produce functional intermediate moisture fruit and fruit products.

Another aim of this invention is to incorporate such a considerable amount of polyphenol compound into dried fruits during rehydration that a minimum 50% increase in the total polyphenol content and resulting antioxidant activity will occur in the final rehydrated intermediate moisture fruits. This invention provides a much more beneficial method than the classical rehydration process since it enables not only softening of the firm hard to chew sun-dried fruits, but also enables production of soft fruits enriched with polyphenols having health benefits. This invention puts a method to produce polyphenol rich whole intermediate moisture fruits, fruit pieces or purees.

Another specific purpose of this invention is to produce intermediate moisture fruits that have considerably higher total polyphenol content and antioxidant activity than similar standard intermediate moisture fruits. For this purpose the invention involves a planned rehydration of dried fruits in particularly selected and prepared polyphenol rich extracts (such as green tea and grape seed extracts), polyphenol rich fruit juice concentrates, and polyphenol rich concentrated tea infusions (such as green and black tea infusions).

Another aim of this invention is to obtain a final fruit product at such a suitable intermediate moisture level that the product will have a reasonable technological shelf-life and polyphenol stability. One of the advantages of this invention is that it enables obtaining a sufficient increase in the total polyphenol content of the rehydrated fruits and producing uniform (standard) intermediate moisture fruits containing similar amounts of total polyphenol content since it is possible to change the polyphenol content of the rehydration medium by changing the concentration of phenolic extracts, amount of tea used to obtain the tea infusions and brix of the fruit juice concentrates. The whole fruits, fruit pieces and purees obtained by this invention could be preserved by food additives, pasteurization or cold storage before marketing to the consumers.

Detailed Description of The Invention

Different steps of this invention that aims producing polyphenol enriched intermediate moisture fruits and fruit products from dried fruits were given at the attached figure given below.

This figure;

Figure-1 The schema of the method to produce polyphenol enriched intermediate moisture fruits from dried fruits

The steps of production were numbered one by one and the meaning of each number was given below. 1. Method

The method of producing polyphenol enriched intermediate moisture fruits from dried fruits discussed in this invention (1); - Rehydration of fruits in polyphenol rich solutions having high antioxidant activity until reaching of final moisture content between 22% and 50% (101),

- Different fruits are selected such as sun-dried raisins, figs, plums, apricots (sulfur containing or not) (102),

- Different polyphenol rich rehydration mediums having high antioxidant activity are selected such as concentrated green or black tea infusions, grape seed or peel and green tea phenolic extracts, and fruit juice concentrates like pomegranate juice concentrate (103),

- Rehydration process was applied by immersing dried fruits in specified polyphenol rich rehydration mediums under refrigeration (at +4°C), at room temperature (at 25°C) or at elevated temperatures (between 30 °C and 100°C) (104),

- Polyphenol enriched intermediate moisture whole fruits are obtained as a final product. Alternatively whole polyphenol enriched fruits might be further cut into pieces at the desired size or processed into fruit puree if needed (105),

- The whole fruits, fruit pieces or puree obtained by this method should contain minimum 50% higher total polyphenol content than whole fruits, fruit pieces or puree obtained from dried fruits with the classical rehydration process (106) is formed by the steps given above.

One of the greatest problems in modern world is the rapidly changing consumption habits. The increased trend of consuming fast foods has caused reduced consumption of fresh fruits and vegetables and their invaluable components such as dietary fiber and antioxidant phenolic compounds that have very important health benefits on human. As a result of increasing fast food consumption, diseases like digestive disorders, cancer, heart and cardiovascular diseases, obesity, etc. have been increased continuously and this causes much more concerns about the consumption habits of modern life.

Dried fruits are rich sources of dietary fiber and their frequent intake could help increasing the bowel movements and controlling related health problems. Due to their delicious taste and texture dried fruits are loved by most people, thus, they could be suggested as source of dietary fiber with the exception of people who are suffering from diabetes and should avoid food rich in sugars. This invention aims producing intermediate moisture fruits enriched with polyphenol compounds (containing minimum 50% higher polyphenol content than similar intermediate moisture fruits obtained from dry fruits). The fruits obtained by the method described in this invention will be not only a rich source of dietary fiber, but also a rich source of polyphenol compounds that have different potential benefits on human health.

Compared to fresh fruits, dry foods have a considerably longer shelf-life and storability. Moreover, it is also quite practical to carry and consume a dry fruit than a fresh one within the rush of modern life. For example, a film or paper wrapped dry fruits could be kept in a hand back for a long time without spoilage or leakage of its juice. Moreover, a dry fruit does not need peeling and pitting and it could be easily handled and consumed without leaving any juice on hands or accidental colored stains of juice on cloths. These advantages provide a great opportunity to consume dry fruits anytime, e.g. during travelling by public transportation, walking at street or a meeting at the job. This invention provides an opportunity to increase daily polyphenol intake via consumption of polyphenol enriched intermediate moisture fruits. This invention also provides an opportunity for people who do not like drinking green and black tea, pomegranate juice or eating grapes with their seeds, but would like to intake antioxidant polyphenol compounds of these products due to their well-known health benefits. The dry fruits have a characteristic dominant flavor and a sweet taste and they can mask the original tastes of specified food products. This invention provides a cheaper and more natural method for polyphenol intake than using pills containing pure concentrated phenolic compounds.

The method described in this invention is used to incorporate antioxidant polyphenol compounds having potential health benefits into dry fruits during rehydration and producing polyphenol enriched intermediate moisture fruits and fruit products. The method described in this invention involves the rehydration of dry fruits in antioxidant polyphenol rich mediums such as concentrated green or black tea infusions (the percentage of tea added in water during infusion making is between 5% and 10%), phenolic green tea and grape seed extracts (prepared by dissolving pure extract in water at concentrations between 1 and 5%), or pomegranate concentrate (Brix of concentrate was between 15 and 35 g/g). The polyphenols are incorporated into dried fruits by absorption of polyphenol rich rehydration medium by the dry fruits. In this method described in the invention the polyphenol concentration of the rehydration medium and the rehydration period should be set and controlled carefully to have minimum 50% increase in the total polyphenol content of final rehydrated product. The rehydration temperature during the method described in the invention could be between +4°C and 100°C, and the final moisture content of the product could be between 22 and 50%. The final polyphenol enriched product could be marketed as a whole fruit or it could be further treated to obtain fruit pieces or puree. The microbial stability of the product could be achieved by using chemical preservatives alone (should be added into rehydration medium) or in combination with refrigeration (+4°C), or by applying pasteurization to the final packed product.