Processing of Squashes


Among the various activities, which are termed agriculturally based, fruits and vegetable processing are the most important. Over recent years, consumers have shown an increasing interest in health and wellbeing, with many wanting food and drink products that are healthy and nutritious yet fit in with busy lifestyles. Fruit Squashes is one beverage that has seen a dramatic increase in consumer demand, especially in summers. So let’s find out what is it and how is it processed.

Definition of Squash:

Squash is a non-alcoholic concentrated syrup that is usually fruit-flavored and usually made from fruit juice, water, sugar, or a sugar substitute. Some traditional squashes may contain herbal extracts, most notably elderflower and ginger. Squash must be mixed with a certain amount of water before drinking. Citrus fruits (particularly orange, lime and lemon) or a blend of fruits and berries are commonly used as the base of Squash

As per FSSAI specifications, the Squash should contain no less than 25 per cent fruit content in the finished product, and the total soluble solids content should not be less than 40° Brix. The acidity of the Squash should not be more than 3.5 per cent as anhydrous citric acid. The maximum permissible limit of preservative in Squash is 350ppm of sulphur dioxide or 600 ppm of benzoic acid. Potassium metabisulphite is not added in dark coloured fruits as it may bleach the anthocyanin pigments. In such beverages, sodium benzoate is used.

 

Processing:

  1. Selection of fruit: Ripe fruits are selected. Overripe and unripe fruits adversely affect the quality of the juice.
  2. Washing: Dirt and spray residues of arsenic, lead etc., are removed by washing with water or using dilute hydrochloric (HCl) acid solution (0.5%) followed by washing in water.

  1. Sorting and grading: Send the fruits to the grading and sorting table/machine to manually check the uniformity of ripened fruits.

  1. Peeling/deseeding/destoning: As per the fruits selected, it is sent for peeling, de-seeding and de-stoning process (removal of seeds).

  1. Cutting/slicing/crushing: Conduct the slicing operation of the peeled fruit using a slicer and send it to the crusher. Depending on the type of fruit used an appropriate machine/ press to extract the juice. E.g. citrus fruits, which are naturally juicy, use a mechanical presser to extract the juice. In the case of fruits such as mango, guava, pineapple, strawberry to extract the juice, first pulp is extracted by pushing through a perforated metal plate

 

  1. Pasteurization: Once the juice is extracted, it is sent for pasteurization at 80-95°C for 10-12 mins. Three types of pasteurizer are generally used for juices plate pasteurizer, tubular pasteurizer and steam pasteurizer, and plate pasteurizer is the most prevalent.

Plate Heat  Exchanger working:

These plates are commonly made of steel, aluminum alloy, titanium, nickel, or even graphite materials and are the thermally conductive pathways between the two working fluids. Their corrugations increase surface area and create turbulence, both of which help enhance the heat transfer rate through the exchanger. One fluid (red) enters its inlet through the top right and successively flows down every even-numbered plate, while the other fluid (blue) enters through the bottom left and is pumped up every odd-numbered plate. This ordering allows for operators to easily add/remove plates to the stack, effectively increasing or decreasing the heat exchanger’s heat transfer capacity at any time.

  1. Clarification: Rapid methods such as centrifugation(with a speed of 6000 to 6500 RPM. and filtration can produce a clear juice. A continuous or a decanting centrifuge with automatic desludging to produce a clear or nearly clear juice is quite effective. Ultra-clarifier can also be used.

  1. Syrup preparation: Simultaneously, sugar, water and acid is mixed and heated to dissolve to form a syrup.
  2. Mixing: Syrup and clarified juice are mixed in a tank.
  3. Addition of preservative: Sodium benzoate or KMS is generally used.1.0gm/lit is used in case of Sodium benzoate.
  4. Cooling: The product is cooled to room temperature.
  5. Deaeration: Freshly extracted juice contains appreciable quantity of oxygen which may affect the quality of juice if not removed before packing.
  6. Bottling and capping. Aseptic processing and packaging is done which are defined as- when a commercially sterile product is packed into a pre-sterilized container in a sterile environment.

Process flow chart of Squash:

Following is the process flow chart of fruit squash.

Conclusion:

Squash is a diluted fruit juice. Among all beverages, Squash is quite popular all over the world. It consists of strained juice containing moderate fruit pulp quantities (optional) to which sugar is added for sweetening. Acid is added to lower the pH, which arrests microorganisms responsible for spoilage of the product. The acid, in combination with sugar, also improves the taste of sugar. Sulphur dioxide (SO2) is also used as a preservative to prevent non-enzymatic browning reaction.

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