Title of Invention

A PROCESS FOR THE PREPARATION OF SHELF STABLE DEHYDRATED LITCHI

Abstract The present invention relates to a process for the preparation of shelf stable dehydrated litchi. Litchi (Litchi chinensis) is an important tropical fruit with a mild and characteristic flavor. The main problems encountered in the processing of litchi are discoloration or browning and short storage life of fresh litchi. The process developed in the present invention facilitates the preparation of a shelf stable dehydrated litchi resembling a resin. The peeled litchi fruit is treated with additives to retain the color, flavor and to remove the moisture. The moisture content of the treated litchi fruits is reduced to the desired level under controlled conditions to make the product shelf stable. The product is coated with suitable additives to prevent stickiness and packed.
Full Text The present invention relates to a process for the preparation of shelf stable dehydrated litchi.
Litchi (Litchi chinensis) is an important tropical fruit with a mild and characteristic flavor. The fruits have a short season of 1 to 2 months. Litchis are mainly consumed in fresh form. The fruit is processed in to different products such as litchi juice, canned litchi, litchi squash, litchi nectar etc., The main problems encountered in the processing of litchi are discoloration or browning and short storage life of fresh litchi. The process developed in the present invention facilitates the preparation of a shelf stable dehydrated litchi resembling a raisin.
Reference may be made to Moran.l. 2000. Process for preserving product quality of lychee, US patent 6093433, where in an improved process for the preparation of the product quality of litchi is described. The process involves trating fresh lychee with cold water then hot water followed by hydrochloric acid, prior to drying the liquid off the surface of the fruit. The main draw back of this process is the extension of shelf life of the litchi is not significant.
Reference may be made to Zhao-Huahai, Li-Changyou, and Guan-Zhiji, 1999, Experimental research on drying characteristics of litchi, Drying technology, 17(9) 1915-1925 wherein changes in inner temperature and drying characteristics of rind, membrane, flesh and stone of litchi were examined at different temperature and under atmospheric and decompression conditions. Decompression drying aided moisture evaporation, when the moisture content was reduced to a critical level, the drying rate was higher than that during atmospheric drying. During the initial drying moisture evaporated mainly from the rind. The membrane was able to prevent moisture moving out of the flesh or the stone. The main draw back of this process is it requires high capital investment and the process is cumbersome.
Reference may be made to Dachapan, U and Phoungchandang.S. 1992. Litchi drying at the village level as a means of extending litchi processing. Food.22(2)21-31 wherein an attempt of process the excess production of litchi in northern Thailand a bin drying method was tested. Litchis were blanched with water or Na oH solution, with and without sulphitation, prior to drying. It was noted that high drying rate of lithcis was observed when blanched in Na oH solution. The main drawback of this process is it involves the use of Na oH which may have detrimental effect on quality.
Reference may be made to Ming-Chang-Wu and Tzuu-Tar-Fang, 1993. Prevention of pink discoloration in canned lychee fruit, J of Chinese Agricultural Chemical society, 31(5) 667-672, where in the factors causing pink discoloration and control measures were investigated. Lowering the pH and adding polyphosphate(0.2%) enhanced formation of pink color. The main drawback of the process is by using this method the pink color formation can not be prevented and the product is not shelf stable.
Reference may be made to Yueming-Jiang, Jiarui-Fu, Zauberman.G. Fuchs, 1999. Purification of polyphenol oxidase and the browning control of litchi fruit by glutathione and citric acid, J of Sci. of Fd. and Ag. 79(7) 950-954, wherein effects of ascorbic acid, L-cysteine, glutathione or n-propyl gallate (each at cone. Of either 1 or 10mmol/liter), used alone or in combination with citric acid, on in vitro inhibition of PPO extracted and purified from litchi peel were studied. Inhibitory effects of the 4 compounds studied were enhanced both at higher concentration and by addition of citric acid. Application of a mixture of gultathione and citric acid may reduce browning in litchis. The main draw back of this process is the product is not shelf stable.
The main object of the present invention is to provide a process for the preparation of shelf stable dehydrated litchi which obviates the draw backs as detailed above.
Another object of the present invention is to provide a process for preparation of shelf stable dried litchi with better color, flavor and other quality characteristics.
Still another object of the present invention is to provide a process for the ready to eat raisin like product from litchi.Yet another object of the present invention is to develop a process for the preparation of intermediate moisture litchi product.
Accordingly the present invention provides a process for the preparation of dehydrated product from litchi which comprises;
a) selecting litchi fruits having optimum maturity,
b) washing and peeling of the litchi,
c) treating the peeled litchi in solution containing organic acid selected from malic acid, citric acid, tartaric acid or a combination of these at a concentration of 0.01 to 5 %,
d) optimally treating the litchi with calcium salts viz., calcium chloride, calcium gluconate at a concentration of 0.01 g to 5% for 1 to 30 minutes,
e) treating the litchi with sucrose syrup having concentration ranging between 60-70 brix at a temperature of 40-80°C,
f) removing the treated litchis from the dip solution and drying at a temperature of 40-60°C to a final moisture content ranging from 15-20%,
g) coating the dried litchi with pulverised sucrose or starch or dextrin or a combination of these to obtain dehydrated shelf stable litchi fruit.
In an embodiment of the process the peeled litchi is treated along with seed to increase the surface area during the treatment.
In an another embodiment of the process the peeled litchi is treated in a hypotonic solution containing osmotic agents such as sucrose in the preferred range of 65-68% solution.
In an another embodiment of the process the composition of the shelf stable dehydrated litchi is as follows:
Moisture (g/1OOg) 15-25
Reducing sugar (g/1OOg) 60-68
Total sugar (g/1OOg) 65-75
Acidity (g/1OOg) 1.5-3.5
Dehydration ratio 10-12.5
In an another embodiment of the process the sensory characteristics of the shelf stable dehydrated litchi on a 10 point scale is a follows:

Colour 7.9
Flavour 8.1
Taste 8.3
Texture 8.2
Overall Quality 8.1
In yet an another embodiment of the process the dried litchi is coated with powdered sucrose or starch or dextrin or a combination of these to prevent stickiness.
These and other objects are achieved, according to the invention where A process for the preparation of dehydrated litchi which comprises selection of litchi fruits of optimum maturity, washing, peeling of the litchi, treating the peeled litchi in solution containing organic acid viz., malic acid, citric acid, tartaric acid or a combination of these at a concentration of 0.01 to 5 %, or calcium salts viz., calcium chloride, calcium gluconate at a concentration of 0.01 g to 5% for 1 to 30 minutes, or SO2 at a concentration of 500 to 1500 ppm or alternatively treating with a sucrose syrup of concentration or 60-70 brix, at 40-80°C, or a combination of the above treatments to achieve the desired effect, removing the treated litchis from the dip solution, drying in a drier at 40-60°C to a final moisture content ranging from 15-20%, coating the dried litchi with pulverised sucrose or starch or dextrin or a combination of these, packing in a suitable packaging material and store.

Novelty
A shelf stable raisin like product from litchi can be prepared. The peeled litchi fruit is treated with additives to retain the color, flavor and to remove the moisture. The moisture content of the treated litchi fruits is reduced to the desired level under controlled conditions to make the product shelf stable. The product is coated with suitable additives to prevent stickiness and packed.
The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention.
EXAMPLE - 1
Litchis fruits of ripe, mature were washed in tap water and peeled. The peeled fruit (10kg) were treated in a 10 liter solution containing calcium chloride (100g), citric acid (20g) and potassium metabisulfite (5g) for 15 minutes. The treated fruits were further treated in a 6 kg solution containing 420 grams sucrose at 70°C for 30 minutes to partially remove the moisture. The treated fruits are drained from the syrup and loaded on a stainless steel mesh tray. The material (7700g) is dried at 50°C in a hot air drier to a final moisture content of 15%. The dried material (2480g) is cooled to ambient temperature and coated with soluble starch powder. The material is packed in metallized polyester polyethylene pouches, sealed and stored.
EXAMPLE - 2
Litchis of optimum maturity and color were selected, washed in tap water and peeled. The peeled fruits (10kg) are treated in a 10 liter solution containing calcium chloride (70g), citric acid (10g), malic acid (10g) and potassium metabisulfite (2.55g) for 20 minutes. The treated fruits were further treated in a 6 kg solution containing 420 grams sucrose at 60°C for 30 minutes to partially remove the moisture. The treated fruits are drained from the syrup and loaded on

a stainless steel mesh tray. The material (8300g) is dried at 50°C in a dried to a final moisture content of 15%. The dried material (2895g) is cooled to ambient temperature and coated with soluble starch powder. The material is packed in metallized polyester polyethylene pouches, sealed and stored.
EXAMPLE - 3
Litchis of optimum maturity and color were selected, washed in tap water and peeled. The peeled fruits (10kg) are treated in a 10 liter solution containing calcium chloride (100g), malic acid (20g) for 20 minutes. The treated fruits were further treated in a 10 kg solution containing 700 grams sucrose at 50°C for 30 minutes to partially remove the moisture. The treated fruits are drained from the syrup and loaded on a stainless steel mesh tray. The material (9117g) is dried at 50°C in a dried to a final moisture content of 15%. The dried material (2990g) is cooled to ambient temperature and coated with soluble starch powder. The material is packed in metallized polyester polyethylene pouches, sealed and stored.
EXAMPLE - 4
Litchis of optimum maturity and color were selected, washed in tap water and peeled. The peeled fruits (10kg) are treated in a 10 liter solution containing calcium chloride (100g), citric acid (20g) and potassium metabisulfite (5g) for 20 minutes. The treated fruits are drained from the syrup and loaded on a stainless steel mesh tray. The material (10050 g) is dried at 50°C in a dried to a final moisture content of 15%. The dried material (3008g) is cooled to ambient temperature and coated with soluble starch powder. The material is packed in metallized polyester polyethylene pouches, sealed and stored.
EXAMPLE - 5
Litchis of optimum maturity and color were selected, washed in tap water and peeled. The peeled fruits (10kg) are treated in a 10 liter solution containing calcium chloride (100g), citric acid (20g) and potassium metabisulfite (5g) for 20

minutes. The treated fruits are drained from the syrup and loaded on a stainless steel mesh tray. The material (10040 g) is dried at 50°C in a dried to a final moisture content of 15%. The dried material (2961 g) is cooled to ambient temperature and coated with soluble starch powder. The material is packed in metallized polyester polyethylene pouches, sealed and stored.







We claim:
1. A process for the preparation of shelf stable dehydrated litchi which comprises:
a) selecting litchi fruits having optimum maturity,
b) washing and peeling of the litchi,
c) treating the peeled litchi in solution containing organic acid selected from malic acid, citric acid, tartaric acid or a combination of these at a concentration of 0.01 to 5%,
d) optimally treating the litchi with calcium salts viz., calcium chloride, calcium gluconate at a concentration of 0.01g to 5% for 1 to 30 minutes,
e) treating the litchi with sucrose syrup having concentration ranging between 60-70 brix at a temperature of 40-80°C,
f) removing the treated litchis from the dip solution and drying at a temperature of 40-60°C to a final moisture content ranging from 15-20%,
g) coating the dried litchi with pulverised sucrose or starch or dextrin or a combination of these to obtain dehydrated shelf stable litchi.

2. A process as claimed in claim 1, wherein the peeled litchi is treated along with seed to increase the surface area during the treatment.
3. A process as claimed in claim 1, wherein the preferred concentration range of sucrose is 65-68%.
4. A process as claimed in claim 1, wherein the shelf stable dehydrated litchi has moisture 15-25 g/100g, reducing sugar 60-68 g/100g, total sugar 65-75 g/100g, acidity 1.5-3.5 g/100g and dehydration ratio 10-12.5.
A process for the preparation of shelf stable dehydrated litchi substantially as herein described with reference to the examples accompanying this specification.

Documents:

591-DEL-2004-Abstract-(06-05-2010).pdf

591-del-2004-abstract.pdf

591-DEL-2004-Claims-(06-05-2010).pdf

591-del-2004-claims.pdf

591-DEL-2004-Correspondence-Others-(06-05-2010).pdf

591-DEL-2004-Correspondence-Others-(20-08-2010).pdf

591-del-2004-correspondence.pdf

591-DEL-2004-Description (Complete)-(06-05-2010).pdf

591-del-2004-description.pdf

591-DEL-2004-Form-2-(06-05-2010).pdf

591-DEL-2004-Form-3-(06-05-2010).pdf

591-del-2004-form1.pdf

591-del-2004-form2.pdf

591-del-2004-form3.pdf

591-del-2004-form5.pdf


Patent Number 244532
Indian Patent Application Number 591/DEL/2004
PG Journal Number 51/2010
Publication Date 17-Dec-2010
Grant Date 09-Dec-2010
Date of Filing 24-Mar-2004
Name of Patentee COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110 001, INDIA
Inventors:
# Inventor's Name Inventor's Address
1 PASUPULETI VIJAYANAND CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSORE-570013, INDIA
2 SHYAMRAO GURURAO KULKARNI CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSORE-570013, INDIA
3 ASWATHANARAYANA USHADEVI CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSORE-570013,INDIA
4 KANUMURI VENKATA RAMA RAMANA CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSORE-570013, INDIA
PCT International Classification Number A23B 7/10
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA