Rheological Behaviour of Sheared Jams. Relation With Fruit Content

Abstract

Eight samples of jam were sheared to destroy gel structure and their pow behaviour was analysed in a concentric cylinder viscometer. Jams were prepared from 4 different fruits-strawberry, peach, plum, and apricot-at 50% and 30% fruit content approximately. Flow of sheared jam showed time dependence, which could be quantified by the Weltmann model and which was eliminated by shearing samples for 8 min at 300 rpm. Casson's yield stress values were obtained at two ranges of shear rates: 0.08-1.01 s-l (uol) and 2.58-387.30 s-' (uo2). co2 values were about double the uol values. Flow was adequately described by the Herschel and Bulkley model, introducing either of the yield stress values (uo, or uo2). Signijicant diferences were found for some of the rheological parameters studied (Weltmann A and B constants, uo,, uo2, K,, and n,) between samples containing 50% and 30% fruit. These results demonstrate the role played by fruit particles in the rheological behaviour of this type of product and suggest the possibility of using rheological parameters as indices of fruit content in jams.

Flow behaviour of semi-solid dairy desserts. Effect of temperature

“…Flow behaviour. Before analysing flow behaviour, the structure responsible for thixotropy was previously destroyed by shearing (Halmos & Tiu, 1981;Carbonell et al, 1991a;Nguyen et al, 1998;Abu-Jdayil, 2002). After testing several shearing conditions, for 5 min at 100, 200, and 300 s À1 shear rates, and analysing the hysteresis cycles, a previous shearing of 5 min at 300 s À1 was selected as the appropriate treatment to get a nule hysteresis area.…”

“…ee et al, 1966;Barbosa-C! anovas & Peleg, 1983;Carbonell, Costell, & Dur! an, 1991a;Thebaudin et al, 1998).…”

Effect of Concentration and Temperature on Flow Properties of Alyssum homolocarpum Seed Gum Solutions: Assessment of Time Dependency and Thixotropy

“…The hysteresis area will give an estimate of the magnitude of the product thixotropy [7][8][9][10] . Modeling of the thixotropic behavior of food products has been based on equations, such as the Weltman model 11 , stress decay models 12 , and structural kinetic models 13 .…”

Sucrose Replacement by Sweeteners in Strawberry, Raspberry, and Cherry Jams: Effect on the Textural Characteristics and Sensorial Profile—A Chemometric Approach

“…Rheological properties are useful in determining ingredient functionality in the product development, quality control, and correlation of food texture to sensorial attributes [23,24]. Rheological properties of jams have been widely studied [25][26][27][28]. It has been established that their rheological properties are mainly affected by the amount and type of sugar added, proportion and kind of gelling agent used, fruit pulp content, and processing temperature.…”