RO (reverse osmosis) Tomato Paste
—External characteristics and quality of fresh tomato and tomato concentrates
Today an increasing number of buyers creates a demand for tomato paste of better sensory quality and attributes such as colour, flavour, texture and nutrition facts. Traditional technology for tomato paste and other concentrated tomato products is based on heat treatment. The most commonly used vacuum evaporators can cause thermal damage to heat sensitive components and loss of volatile flavour and aroma compounds, as well as inducing undesirable colour changes such as browning.
RO ( reverse osmosis ) tomato paste is a low temperature methods of concentration for tomato paste. Reverse osmosis processes have the capacity to remove water at lower temperatures, thus minimising thermal damage to heat sensitive components and loss of volatile flavour and aroma compounds and inconsistent product colour. Reverse osmosis’s main advantages is improvement of the qualitative indexes of the final products, such as: colour, flavour, nutritional quality.
Consumers often associate better eating quality both tomato paste and fresh tomato with better colour. The redness of tomatoes is mainly due to the lycopene,carotenoid, phytoene, phytofluene,β-carotene and γ-carotene. For preservation of colour, low temperature concentration methods such as reverse osmosis processing may be more suitable than conventional thermal vacuum evaporation methods.
The overall flavour of fresh and processed tomatoes is influenced by a combination of factors including varietal differences, titratable acidity, growth conditions, post-harvest storage conditions, and stage of ripeness. The flavour is usually the most dominant sensory feature in processed tomato products. The variation in flavour of tomato paste is determined by the sugar content( fructose and glucose) and acidity level(citric and malic)of the soluble solids content of tomatoes. For preservation of colour and flavour, low temperature concentration methods such as reverse osmosis processing may be more suitable than conventional thermal vacuum evaporation methods.
The texture of tomatoes is as important in the production process as it is during the harvesting stage. The pericarp of the tomatoes has to be firm enough to withstand
mechanical injury during harvesting, storage and subsequent processing.The texture of tomato is influenced by the balance of constituents such as cellulose, hemicellulose, pectic substances and cell wall proteins.
Raw tomatoes contain a good balance of vitamins and minerals, in particular vitamins A and C. The vitamin C content of tomatoes is higher than in most fruits and vegetables except for potatoes and citrus fruits. The vitamin content of tomatoes is dependent on the genetic origin, environmental factors, geographical location and post-harvest handling techniques. In reverse osmosis process facilities, tomatoes are protected by using a thermal process for a very short time; therefore, vitamins are protected with less loss.