Application of evaporators in fruit and vegetables processing
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Transcript of Application of evaporators in fruit and vegetables processing
Application of Evaporators in
Fruit and Vegetable
Processing
Submitted to: Submitted By: Preeti Birwal
Dr. Rekha Menon PhD (DE)
NDRI
Introduction
The process of evaporation is widely used to concentrate foods
Evaporation technology is a process of separating substances by
means of thermal energy. The concentrated liquid, which is still
pump able, usually is the desired final product.
Three element: Heat transfer, Vapor-liquid separation and vapor
condensation
Objectives
To reduce water activity and lengthen shelf life
To reduce packaging, transportation, and storage cost (Reduction inbulkiness)
To improve the stability and handling of the product.
It may be used as an economical preparatory step for subsequentdehydration, as in the cases of spray drying, drum drying, vacuumdrying, freeze-dried, crystallization and mixing (Food mixing).
Pre-concentration reduces cost of energy for subsequent processes.
Concentrate as commodity is easier to market.
Applications
Evaporators are used in a wide range of processes,
including pharmaceuticals, foods, beverages, juices
dairy industry, sugar syrups, pulp and paper,
chemicals, polymers and resins, inorganic salts,
acids, bases, and a variety of other materials.
Fruits and Vegetables
Fruit puree( Grapes, apple,
cherry)
Grape juice
Lime juice
Pear juice
Pineapple juice
Mango juice
Orange juice
Citrus juices
Blueberry juice
Beetroot juice
Carrot juice
Passion fruit juice
Acerola juice
Coconut juice
Other vegetable juices
Selection of Evaporators
Evaporators chosen all on fruit properties: chemical, rheological and
thermal.
The necessary high final concentrations, depend on the type of fruit,
degree of ripeness, juice production method, pretreatment and the
fiber and pulp proportion.
For most fruit juices, 316 stainless steel is used
Types of Evaporators
Unstirred Open Pan or Kettle
Multi-effect Evaporator: Falling and Rising
Short Tube Vertical Evaporator
Agitated Thin Film Evaporator (ATFE)
Thermally Accelerated Short Time Evaporators (TASTE)
Plate evaporators: Falling Film, Rising/Falling Film, Paravap, Paraflash
Centritherm
Falling Film Long Evaporator (FFLE)
Scraped Surface Evaporator (SSE)
Unstirred Open Pan or Kettle: operating at atmospheric pressure, steamjacketed or heated with closed steam coils and are used for concentration ofsauces, jams, and confections products, operating temperatures is 100.8°C
Falling Film Evaporator: largely used for fruit juices.
Plate Evaporators: can be used on a broad range of products, the mainapplication has been with products that are heat sensitive and therefore benefitfrom the high HTC’s and low residence time.
Rising/Falling Film Plate Evaporator: use in juice processing for product where low residence time and less temperature below 90°C is required.
Falling Film Plate: system with the added benefits of shorter residence time and largerevaporation capabilities, has wide acceptance for heat sensitive products.
Paravap: thin film turbulent evaporator, atomize systemprovide grater surface area. Finishing evaporator toconcentrate materials to high solids. Used for apple puree(70°Brix), Cherry puree (60°Brix) and grapes puree(50°Brix)
Paraflash: suppressed boiling, forced circulation, used forproduct which subject too high fouling in falling filmevaporators. Ex. grape juice etc.
Short Tube-Vertical Evaporator: concentration of sugarcane juice.
Scraped Surface Evaporator: for tomato puree (Highlyviscous)
FFLE (Falling Film Long Evaporator): is the current development in the plate
evaporator technology. Has a 50% longer flow path. This creates thinner films off the plate,
with improved wetting characteristics. The FFLE is current state-of-the art technology,
producing concentrates of high quality on a wide range of juices
Centritherm Evaporator: continues to be the evaporator of choice for heat sensitive,
viscous and high value products where color, functionality and flavor are important.
Pineapple juice concentrates from 12°Brix to 87°Brix, Carrot up to 65°Brix, Blueberries up
to 73.5°Brix , Grape juice to 70°Brix and coconut water to 65°Brix. It is used in citrus
energy at higher temperature.
Agitated Thin Film Evaporator (ATFE): concentration of orange juice
Thermally Accelerated Short Time Evaporators: high-temperature short-time, multi-
effect vacuum tubular evaporators, evaporates 65% solids desired for frozen orange juice
Reference
APV, Evaporator hand book.
GEA, Evaporation technology for the juice industry.
Karel M. and Lund B. D. (2003), physical principle of food preservation, second edition, chapter;9, concentration, 330-349.
Kerkai H. E. and Mate S. M., manufacturing fruit beverages and concentration, Handbook of fruit and fruit processing, Authors; Sinha N., Sidhu J., Barta O., Wo J., Chapter;13, 215-228.
Sandhu S. K. and Mindas D. K., Orange and citrus juice, Handbook of fruit and fruit processing, Author; Y. H. Hui, Chapter; 19, 309-357.
Skaliotis L., 2012, Beverage application using spinning cone technology. Food marketing and technology, 26-28.
William B. Glover (2004), Selecting evaporators for process applications, Chemical Engineering Progress, 26-33.