The present invention relates to a process for the preparation of Lemon juice powder.
Lemon is an important tropical fruit and is widely cultivated in India. Lemon juice is used as a refreshing beverage. Lime juice is also used as natural acidulant in a number of traditional food preparations. Limes are processed into different products viz., pickles, syrups, squash, cordial, jelly etc., Lime juice is also a good source of ascorbic acid. Limes are produced in excess during the glut season and there is a need to utilize the surplus lime juice. There fore a process for the preparation of lime juice powder was developed. The process developed in the present invention facilitates the preparation of lime juice powder and instant lime beverage mix.
Reference may be made to Herrera-Robledo.J, Montes, G.A and Dante-Casas, S.J. 1974. Factors in the formation of foams from lemon and tomato juices and in the dehydration process. Anales-Cientificos, 12(3/4) 141-170, wherein experiments for preparation of lemon juice powder by foam drying process. Lemon juice 35°brix was prepared by mixing at 500rev/min for 25 minutes using air or N2 as foaming agents, 0.4% carboxymethyl cellulose as stabilizer and 1% albumin as emulsifier and dried in a tunnel drier. It was reported that air temperature of 60-70C, air velocities of 1.0 and 1.25 m/s and bed thickness of 2 and 4 mm were not suitable to obtain lemon juice powder owing to the chemical structure of the juice. The main draw back of this process it is not possible to produce lemon juice powder from this process.
Reference may be made to Pourny, M.M. and Pourny, L.J.R. 1978. Stabilizing effect of lime or lemon juice on unsweetened condensed milk whipped to a foam, allowing preparation of ices or ice cream with milk and fresh fruit. French patent, wherein lemon juice from antilles lemon or lime, filtered or centrifuged to remove all solid matter, can act as a natural stabilizer for a whipped milk product which may then be made in to a paste with fresh fruit, such as guavas, pineapple or banana. The main draw back of this process is it does not involve the preparation of lime juice powder.

Reference may be made to Kpelman, I.J., Meydav, S. and Weinberg, S. 1977. Storage studies of freeze dried lemon crystals, J of Food Technology, 12(4) 403-410, wherein the shelf life and storage stability of freeze dried pure lemon crystals was studied. Lemon crystals were extremely hygroscopic and exhibited a high tendency to caking on storage at ambient temperature. Free flowing property and reconstitution were preserved when stored at refrigeration temperature. Inert atmosphere packing had no effect on browning. Browning under adverse conditions was preceded by a steep rate of CO2 evolution, thus suggesting CO2 evolution could be used as an early indicator for browning during storage. The main draw back of this process is the freeze drying is a high cost process and is a batch process.
Reference may be made to Borges, S.V., Reis, A.L.S.H., Jorge,E.C., Pinto,P.R., Oliveiera, V.M.2002. Spray drying of tropical fruit juices, Alimentaria, 334, 125-130 wherein the effects of maltodextrin concentration and out let air temperature on physico chemical properties of spray dried tropical fruit juice powders was reported. Pineapple and passion fruit juices were mixed with maltodextrin (20-30%) and spray dried with outlet air temperature of 85-90°C. No significant effects of maltodextrin or outlet temperature ere observed for true bulk density, solubility, wettability or porosity of powders. Yield of pineapple powder increased with inreasing maltodextrin concentration peaking with outlet air temperature of 90°C. Apparent bulk density of powders also increased with increasing maltodextrin concentration. The main draw back of this process is it involves the use of maltodextrin at a very high concentration there by reducing the juice solids content in the powder.
Reference may be made to Boullin, A., Filleau, P. and Megard, D. 2002, Process for manufacture of a dried food product from a moist material of plant origin , FR 2811865 wherein a process for manufacture of dried fruit products or vegetable products is based on drying fruit or vegetable juices or purees on a heated surface of a drum. The process is characterized by application of a film of vegetable oil to the heated surface before application of a thin layer of the fruit or vegetable material. The main draw back of this process is it involves the use of vegetable oil which may cause oxidation and poor product quality during storage.

Reference may be made to Cal-Vidal,J. and Falcone,M. 1985, Processing conditions affecting the hygroscopic behaviour of freeze dried passion fruit juice. Journal of Food science, 50 (5), 1238-1241, 1253. The effect of freezing rate, freeze drying temperature, added sucrose and anticaking agents on the water sorption kinetics and hygroscopic equilibrium of freeze dried passion fruit juice were reported. Slow frozen samples (-45C) and fast frozen (-195.8C) in liquid nitrogen were prepared and dried in a stokes freeze drier. Influence of the rate of freezing and added sucrose on reducing product hygroscopicity were observed. The main drawback of this process freeze drying is a high capital intensive and batch process.
Reference may be made to Aglio-Gdall, 1979. Foam mat drying in the manufacture of powdered apple and tomato products. FSTA 115G345 wherein a foam mat drying of fruit juices is described. Apple and tomato juices were foamed with the aid of the emulsifier Myverol 1800 (a glycerol monostearate preparation). Foam mat drying resulted in a small increase in the invert sugar content of apple juice and no effect on sugar concentration in tomato juice. The main draw back of this process it is a batch process and involves the use of glycerol monostearate which is not desirable.
Reference may be made to Cantarelli-C. 1975. Preparation of juices for freezed drying, Industrie-delle-Bevande, 4 (6) 80-88, wherein processing of clarified and turbid fruit and vegetable juices for freeze drying is discussed using apple, tomato, vegetable and berry juices. The main draw back of this process is it is an expensive and batch process.
Reference may be made to Maltini, E. 1971. Freeze drying of citrus juices, Annali-deiristituto-Sperimentale-per-la-Valorizzazione-Technologica-dei-Prodotti-Agricoli, 2:327-338 wherein the freeze drying of citrus fruit juices was examined. The main draw back of this process is it is an expensive and batch process.
Reference may be made to Salunke, D.K. and Bolin, H.R. 1972. Dehydrated protein-fortified fruit juices, Food product Development 6 (1) 84,86

wherein a protein product (Gunther D-100) enzymatically modified to increase its water solubility and foaming properties was added as a 20% solution to fruit juice (apple, peach or cherry). Juice-protein-methyl cellulose combinations were whipped together for 5 min, the resultant foam spread 1 mm thick on trays and dehdrated at 160f for 25 min, the trays cooled, the friable puffed material removed and ground to pass through a 6 mesh screen. The main draw back of this process is it contains protein substance which may cause browning and effect the flavor of the product.
The main object of the present invention is to provide a process for the preparation of lime juice powder which obviates the draw backs as detailed above.
Another object of the present invention is to provide a process for preparation of lime juice powder with better color, flavor and sensory characteristics.
Another object of the present invention is to provide a process for the lime juice powder without affecting the change in natural pH of the lime juice.
Still another object of the present invention is to provide a process for the preparation of lime juice powder by spray drying.
Yet another object of the present invention is to develop a process for the preparation of lime juice powder by a continuous process.
Accordingly the present invention provides a process for the preparation of lime juice powder which comprises;
a) extracting the lemon juice with out crushing the seeds,
b) refining the juice to remove suspended solids,
c) adding additives selected from ascorbic acid, potassium metabisulfite at a
concentration of 50 to 200 ppm,
d) adding 0.1 to 1.5 % pectin to the juice,

e) adding thickening agent selected from food grade soluble starch,
maltodextrin, dextrin, gum tragacanth, gum karaya, guar gum or a
combination of above in the range of 0.1 to 5% to obtain slurry
f) heating the slurry to a temperature ranging 70-80°C,
g) mixing the slurry to obtain homogenized slurry
h) spray drying the homogenized slurry with an inlet temperature ranging from 110°C to 140°C, out let temperature of 95-110°C to obtain dried lime juice powder,
In an embodiment of the process the lime juice is homogenized at 1000 to 2000 psi to get a uniform suspension.
In an another embodiment of the process the lime juice is pasteurized at 60-95°C and cooled immediately to inactivate the enzymes.
In yet an another embodiment of the process the composition of lime juice powder is as follows:

Moisture (g/100g) 1.62-3.5
Reducing sugar (g/100g) 5.9-6.5
Total sugar (g/100g) 6.5-7.5
Acidity (g/100g) 42-47.5
Vitamin C(g/100g) 70-95.4
Alcohol insoluble (g/100g) 0.2-0.35
PH 2-2.7
These and other objects are achieved, according to the invention where in a process for the preparation of lime juice powder which comprises selection of lime fruits of optimum maturity, washing, cutting and extracting the juice with out crushing the seeds, refining the juice to remove suspended solids, adding ascorbic acid or potassium metabisulfite at a concentration of 50 to 2000ppm, adding 0.1 to 1.5 % pectin to the juice, adding food grade soluble starch or maltodextrin or dextrin or gum tragacanth, gum karaya, guar gum or a combination of any of these in the range of 0.1 to 5% in the form of a slurry made with the juice, heating the slurry to 70-80°C, mixing the juice thoroughly in a blender or homogenizer to a homogeneous state, passing through a spray drier with an inlet temperature ranging from 110°C to 140°C, out let temperature of 95-

110°C, collecting the dried lime juice powder, packing in a suitable flexible packaging material and store.
The novelty and inventive steps of the process of the present invention is it provides a process for the preparation of lime juice powder by spray drying. Lime juice extracted from lime fruits of optimum maturity with bright yellow color and flavor is treated with ascorbic acid, potassium metabisulfite, or calcium chloride or a combination of these to prevent browning. The pasteurized lime juice is added with suitable additives viz., dextrins, pectin, starch, gum, tri calcium phosphate at a predetermined concentration to facilitate drying. The additives are made in to a slurry, preheated mixed with the lime juice and homogenized before drying. The natural lime juice acidity and pH are not altered during the process.
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
Lime fruits mature, ripe were washed in tap water, cut and the juice extracted. Lime juice (10kg) is passed through a pulper refiner system to remove the insoulble solids. Lime juice is pasteurized at 75°C and cooled immediately to in a chilled water bath. Pectin 50grams, soluble starch 200grams, calcium gluconate 10grams were added to a 2liters of lime juice and made into a slurry, heated to 70°C, blended with the remaining lime juice and homogenized in an homogenizer. The homogenized blended lime is fed in to the spray drier at an inlet temperature of 125°C and outlet temperature of 100°C. The powder was collected in the receiving vessel, transferred to a glass bottle and stored.
EXAMPLE - 2
Lime fruits mature, ripe were washed in tap water, cut and the juice extracted. Lime juice (1 Okg) is passed through a pulper refiner system to remove the insoluble solids. Lime juice is pasteurized at 70°C and cooled immediately to in a chilled water bath. Pectin 60 grams, soluble starch 200grams, 5grams

potassium metabisulfite were added to a small quantity of lime juice (2litre) and made into a slurry, heated to 78°C, blended with the remaining lime juice and homogenized in an homogenizer. The homogenized blended lime juice is fed in to the spray drier at an inlet temperature of 130°C and outlet temperature of 105°C. The lime juice powder was collected in the receiving vessel, transferred to a metallized polyester-polyethylene pouch, sealed and stored.
EXAMPLE - 3
Lime fruits mature, ripe were washed in tap water, cut and the juice extracted. Lime juice (10kg) is passed through a pulper refiner system to remove the insoluble solids. Lime juice is pasteurized at 70°C and cooled immediately to in a chilled water bath. Pectin 40 grams, soluble starch 250 grams, 5 grams ascorbic acid were added to a small quantity of lime juice (2litre) and made into a slurry, heated to 70°C, blended with the remaining lime juice and homogenized in an homogenizer. The homogenized blended lime juice is fed in to the spray drier at an inlet temperature of 125°C and outlet temperature of 100°C. The lime juice powder was collected in the receiving vessel, transferred to a metallized polyester-polyethylene pouch, sealed and stored.
EXAMPLE - 4
Lime fruits mature, ripe were washed in tap water, cut and the juice extracted. Lime juice is passed through a pulper refiner system to remove the insoluble solids. Lime juice (10kg) is pasteurized at 70°C and cooled immediately in a chilled water bath. Pectin 50 grams, soluble starch 100 grams, maltodextrin 100 grams, 2.5 grams potassium metabisulfite were added to a small quantity of lime juice (2litre) and made into a slurry, heated to 70°C, blended with the remaining lime juice and homogenized in an homogenizer. The homogenized blended lime juice is fed in to the spray drier at an inlet temperature of 130°C and outlet temperature of 105°C. The lime juice powder was collected in the receiving vessel, transferred to a metallized polyester-polyethylene pouch, sealed and stored.

EXAMPLE - 5
Lime fruits mature, ripe were washed in tap water, cut and the juice extracted. Lime juice is passed through a pulper refiner system to remove the insoluble solids. Lime juice (10kg) is pasteurized at 70°C and cooled immediately in a chilled water bath. Pectin 50 grams, soluble starch 100 grams, maltodextrin 150 grams, 2.5 grams potassium metabisulfite, 5 grams tricalcium phosphate were added to a small quantity of lime juice (2litre) and made into a slurry, heated to 75°C, blended with the remaining lime juice and homogenized in an homogenizer. The homogenized blended lime juice is fed in to the spray drier at an inlet temperature of 130°C and outlet temperature of 105°C. The lime juice powder was collected in the receiving vessel, transferred to a metallized polyester-polyethylene pouch, sealed and stored.
The main advantages of the present invention are
1. The process developed in the present invention facilitates preparation of lime
juice powder by spray drying with better color and flavor
2. The lime juice powder prepared from the present invention has acceptable
color and flavor and can be used as a natural acidulant in various food
preparations.
3. The lime juice powder obtained has the natural color, flavor, pH and free from
any off flavor.
4. The lime juice powder is a concentrated source of citric acid and can be used
as a natural acidulant.