engleski

Influence of Essential Onion Oil on Metals and Non-Volatile Compounds During Storage of Canned Tomato Purée

Tinplate has been used for over a hundred years as a robust form for food packaging. It is made of low carbon steel, iron-tin alloy, free tin and passivation film. Some specific food types, including tomatoes and tomato based products affect tin dissolution and then alloy layer, which is the second line of defense for the underlying steel. The dissolution of metals can be minimised by application of lacquers on internal surface of cans or adding the natural substances, which are capable to prevent cans damage. The possibility of using the essentional onion oil as a natural tinplate corrosion reducing substance was investigated. In the first part of analysis, the influence of this spice on metals (Sn, Cr and Fe) in the structure of tinplate was investigated by atomic absorption spectroscopy. In the second part, the action of essential onion oil in contact with caning tomato puree, after storing on 20 and 36 °C was investigated. The results have shown that essential onion oil influence the dissolution of metals Sn and Fe, and development of gases, which are the main corrosion state parameters. On the other hand there is no influence on the non-volatile components of tomato puree. It is well known that tomato flavour is formed by the action of volatile aroma compounds and non-volatile constituents. Sugars, organic acids and free amino acids are the non-volatile components, which contributs to characteristic sweet-sour taste of tomato. Its composition and quantity varies due to the wide range of tomato species, stage of ripeness, year of growth, climatic conditions, light, temperature, soil, fertilization, handling and storage. These studies describe composition and quantity of non-volatile components of canned tomato puree samples which are prepared with and without addition of essential onion oil. The analysis is performed by high performance liquid chromatography during six months of sample storage. The results have shown that quantities of sugars, organic acids and free amino acids remained almost unchanged during analysed period in both groups of canned samples. While precence of essential onion oil does not influence on composition and quantity of non-volatile components its aplication could be favourable in all canned tomato based products.

essential onion oil; tin; iron; non-volatile compounds; tomato purée

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