PREPARATION OF READY-TO-SERVE (RTS) DRINKS

 PREPARATION OF READY-TO-SERVE (RTS)

Aim of the experiment: To study the preparation and storage of RTS.

Objectives:

1.      To know the methods of preparation and preservation of RTS or the unfermented fruit beverage.  

2.      To know the difficulties, precautions to be taken and technical know-how of the final product’s quality.

Materials required:

1.      Fruit/vegetable,

2.      Sugar

3.      Peeler

4.      Juicer

5.      Pulper

6.      Filter cloth/ sieve

7.      Pans of suitable size

8.      Heaters/ Gas

9.      Thermometer

10.  Crown corking/ capping machine

11.  Corks/ caps

12.  Sterilizer/Pasteurizer

13.  Volumetric flask

14.  Measuring cylinder

15.  Weighing balance

16.  Potable water

Chemicals and reagents

1.      Hydrochloric acid

2.      Citric acid/ ascorbic acid

3.      Potassium metabisulphite

4.      Sodium benzoate

Relevant information:

      Tropical countries, like India, have a vast scope of providing delicious cold drinks during hot summer, particularly fruit beverages. Due to increased consumer awareness with respect to quality, safety, and health, these fruit beverages are becoming more and more popular and are gradually acquiring a chunk of the market share of cold drinks. Fruit beverages are easily digestible, highly refreshing, thirst-quenching, appetizing, and nutritionally far superior to synthetic aerated drinks. Fruit beverages can be classified as fermented and unfermented. In this practical, however, we will only deal with unfermented beverages which do not undergo any alcoholic fermentation.

Principles:

            Fruit beverages are prepared from fruit juices or pulp and preserved by chemical preservatives or by heat application. RTS is a type of fruit beverage containing at least 10% fruit juice and 10% total soluble solids besides about 0.3% acid. It is not diluted before serving and, hence, is known as a ready-to-serve (RTS) beverage.

The general method for preparation of fruit juice

💭The general process for the preparation and preservation of unfermented fruit beverages is as follows:

💭Select only fully ripe and quality fruits. Care should be taken not to include either over-ripe or under-ripe fruits as it affects the final product quality.

💭Sort and reject/trim diseased, damaged or decayed fruits. Wash them properly with water or dilute hydrochloric acid (1 part acid: 20 parts water) to remove dirt and spray residues of arsenic, lead, etc.

💭Extract juice from fresh fruits by crushing and pressing them by using suitable juice extractors, basket presses, or fruit pulpers. Fruits, which require preheating, should be preheated before extraction.

💭Strain and filter the juice to remove suspended matter consisting of broken fruit tissue, seed, skin, etc. Clarify the juice if required using a suitable method.

💭Fortify the juices with vitamins to enhance their nutritive value, to improve taste, texture, or colour and to replace nutrients lost in processing, if required.

💭The preservation could be by physical methods (pasteurization, sterilization, etc.) or by chemical preservatives.

💭Wash bottles thoroughly with hot water and fill them leaving 1.5-2.5 cm headspace. Seal with crown corks (by a crown corking machine) or with caps (by a capping machine).

The flowchart of RTS preparation is given below;

Method of preparation of RTS:

For the preparation of 10 l of RTS beverage, follow the procedure given below:-

Ø  Calculate the amount of juice required as per commercial specification

            Required juice = (10/100) × 10 = 1.0 l

Ø  Measure the TSS using a refractometer (say the TSS is 30%)

            Calculate the total solids content of the juice i.e. 0.3 × 1.0 = 0.30 kg

Ø  The final required TSS content in the product is to be say 10%.

            The TSS required to be added to obtain the final product is (0.1×10–0.30) kg = 0.70 kg

Ø  The amount of soluble solids in the form of citric acid and KMS is

            Citric acid @ 0.3%, in the final product, is 30 g i.e. 0.03 kg.

Ø  Amount of solids to be added in the form of sugar is 0.70–0.03=0.67 kg.  

      Add the calculated amount of sugar to about 2 l of water and heat it till it dissolves completely. Add citric acid and juice to the sugar syrup and make up the volume to 10 l and mix it well.

         Heat up to 90°C, fill hot solution in clean pre-sterilized glass bottles up to brim, seal and cool in the air or fill in bottle, seal and heat process (90°C for 25 min.). 

Observations:

            Quantity of fruit/vegetable taken= __________

            Amount of final product prepared=__________

            TSS of the final product=___________˚Brix

Precautions:

1. All equipment used in the preparation of fruit juices and beverages should be rust and acid-proof.

2. Copper and iron vessels should be strictly avoided as these metals react with fruit acids, and cause blackening of the product.

3. Avoid exposure of the juice to the atmosphere as it will spoil the colour, taste and aroma and also reduce the vitamin content.