Influence of homogenisation on the rheological properties of salad mayonnaise

U ovom radu istraživan je utjecaj brzine rotora, vremena homogenizacije, vrste ulja, udjela mliječne komponente na reološka svojstva salatne majoneze. Za ispitivanje korištene su različite vrste biljnih ulja: suncokretovo ulje (rafinirano, hladno prešano), repičino ulje (rafinirano, hladno prešano) i sezamovo ulje (hladno prešano).Mehanički proces homogenizacije majoneze proveden je kod 10 000 o/min i vremenu 3 min pri sobnoj temperaturi. Majoneze sa 65 % uljnom fazom izrađene su po tradicionalnoj recepturi bez dodanog konzervansa čime je trajnost proizvoda vremenski ograničena.Mjerenja reoloških svojstava provedena su na rotacijskom viskozimetru„Rheomat 15T“ s koncentričnim cilindrima pri temperaturi 25 oC. Iz dobivenih podataka izračunati su reološki parametri prividna viskoznost,koeficijent konzistencije i indeks tečenja. Uzorci majoneze pokazuju različita reološka svojstva u ovisnosti od vrste biljnih ulja i udjela mliječne komponente. Dodatak većeg udjela sojinog mlijeka u prahu utječe na porast prividne viskoznosti i konzistencije majoneze. Porast brzine rotora i vremena homogenizacije kod izrade majoneze dovodi do promjene reoloških svojstava.This paper shall research the influence of rotor speed, homogenisation time, sort of oil and milk content on the rheological properties of mayonnaise. Different sorts of vegetable oils were used during the research: sunflower oil (refined, cold pressed), rapeseed oil (refined, cold pressed) and sesame oil (refined, cold pressed). The mechanical process of homogenisation of the mayonnaise has been done at 10,000 revolutions per minute for 3 minutes at room temperature. Mayonnaise with a 65% oil phase is made according to the traditional recipe without added conservatives, which limits its durability. The rheological measurements were performed on a rotating viscometer with concentric cylinders, the Rheomat 15T, at 25 o C. With the use of these results the rheological parameters - apparent viscosity, consistency coefficient and flow behaviour index - have been calculated. The different samples of mayonnaise show different rheological properties depending on the sort of vegetable oil and milk content. The addition of soy milk powder influences the growth of apparent viscosity and the consistency of the mayonnaise. The increase of rotor speed and homogenisation time leads to changes of the rheological properties