Naslov
Studies on the enzymatic browning and polyphenols of apple fruit and apple juice

Autori
Šubarić, Drago ; Piližota, Vlasta ; Nedić Tiban, Nela ; Babić, Jurislav ; Kopjar, Mirela

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Skup
32nd International Symposium Actual Tasks on Agricultural Engineering

Mjesto i datum
Opatija, Hrvatska, 23.02.2004. - 27.02.2004

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
colour; enzymatic browning; apples; polyphenol oxidase

Sažetak
Prevention of browning of fresh-cut apples and apple products (such as juice, cider-juice from freshly squeezed apples separated from the pomace with no further clarification) has been difficult to achieve because of the rapidity of phenol oxydation catalized by polyphenol oxidase (PPO). Generally, a blanch treatment is required in food processing industry to produce products with minimal darkening and with reduced number of spoilage microorganisms or their destruction. In the cases of fresh-cut fruits and vegetables and freshly prepared fruit and vegetable juices thermal treatment can not be applied because it can significantly deteriorate texture of fresh-cut product and flavour. The objective of this work was to investigate an application of benzoic acid, potassium sorbate and monopotassium salt of 2, 5-dimercapto-1, 3, 4-thiadiazol in prevention of enzymatic browning of fresh-cut apples (Jonagold variety) and freshly prepared apple juice. As an indicator for the potential enzymatic darkening can be used the phenol concentration and for that reason the content of phenols in nontreated apple juice and treated with enzymatic inhibitors were determined. Discoloration of the cut surface of the apples were measured with the tristimulus colorimeter, and in apple juice by spectrophotometer. Also, the change of the phenol concentration was spectrophotometricaly monitored during 24 hours. The biggest influence on browning inhibition on fresh-cut apple surface had treatment with a dip containing 0.5 % potassium sorbate. The biggest influence on browning of freshly prepared apple juice, during 24 hours, had an addition of 0.1 mM solution of monopotassium salt of 2, 5-dimercapto-1, 3, 4-thiadiazol as well as addition of 2 mM solution of potassium sorbate.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

POVEZANOST RADA