Instrumental measurement of cooked rice texture by dynamic rheological testing and its relation to the fine structure of rice starch

Abstract

Instrumental measurement of cooked rice texture by dynamic rheological testing and its relation to the fine structure of rice starch.Carbohydrate Polymers http://dx.doi.org/10. 1016/j.carbpol.2016.03.045 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. and dynamic rheological testing) using a set of 18 varieties of rice with a wide range in amylose content (0 -30%). The panellists' results indicated that hardness and stickiness were the two most discriminating attributes among 13 tested textural attributes. The consistency coefficient (K * ) and loss tangent (tan δ) from a dynamic frequency sweep were used to compare with hardness and stickiness tested by TPA and sensory panellists, showing that using K * to express hardness, and tan δ to express stickiness, are both statistically and mechanistically meaningful. The instrumental method is rationalized in terms of starch structural differences between rices: a higher proportion of both amylose and long amylopectin branches with DP 70-100 causes a more elastic and less viscous texture, which is readily understood in terms of polymer dynamics in solution.

Comparison of a Double Compression Test for the Prediction of Sensory Texture Attributes of Cooked Rice to a Single Compression Test

“…Texture defined as "the sensory manifestation of the structure of food and the manner in which that structure reacts to applied force" (Szczesniak, 1987) plays a key role in rice for consumer palatability when consumed as whole grain (Calingacion et al, 2014;Li et al, 2016) although more than ten sensory attributes related to aroma and flavor that characterize rice quality have been identified (Champagne, 2008). As texture is considered as a multidimensional sensory attribute, it can be best perceived and measured by humans (Szczesniak, 1963).…”

“…However, training and maintaining a sensory panel is costly, extensive and excessively timeconsuming as well as variability between human subjects exists. Therefore, there have been increasing demands in methods capable of assessing cooked rice texture and a great deal of effort has been devoted to the development of instruments for the prediction of cooked rice texture (Li et al, 2016;Miao et al, 2016).…”

“…Instrumental methods found in the literature include the General Foods Texturometer (Okabe, 1979;Szczesniak and Hall, 1974), the Instron Food Tester (Juliano et al, , 1984Juliano, 1979, 1981), the Haake Consistometer (Kumar et al, 1976), various uniaxial compression tests (Champagne et al, 1998;Li et al, 2016;Sesmat and Meullenet, 2001), the Ottawa texture measuring system Perez and Juliano, 1979;Rousset et al, 1995;Sitakalin and Meullenet, 2000), the Kramer shear cell , the dynamic rheological testing (Li et al, 2016), and the two-bite instrumental test and Electromyography (Kohyama et al, 2016).…”

Understanding the texture of cooked rice from the molecular, instrumental and sensory levels

“…Both of these clearly relate to how the human mouth would perceive the stickiness of a material to tongue and teeth during the first chew, which explains the TPA/panel data correlations (Li, Prakash, Nicholson, Fitzgerald & Gilbert, 2016b). The quantity defined as TPA stickiness depends on a number of fundamental properties, including the bulk viscosity (Benedek, 2004).…”

“…Texture is a multi-faceted sensory property, with hardness and stickiness as the most commonly determined and discriminable textural properties of cooked rice (Li, Prakash, Nicholson, Fitzgerald & Gilbert, 2016b;Patindol, Gu & Wang, 2010). Rice is the only major cereal that is most often consumed in the form of whole grain after cooking.…”