Quantitative Instrumental Assessment of Cooked Rice Stickiness
- PDF / 726,589 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 6 Downloads / 207 Views
Quantitative Instrumental Assessment of Cooked Rice Stickiness Micha Peleg 1 Received: 9 April 2020 / Accepted: 22 April 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Stickiness is a major textural characteristic of cooked rice and an important criterion in cultivars classification. Many reports on instrumental evaluation cooked rice stickiness are based on variants of the texture profile analysis (TPA), a method that has fundamental methodological flaws and creates logical inconsistencies. Notable among these is that cooked rice tested as a flat cylindrical specimen having a larger diameter is always harder and stickier than when tested as a narrower specimen. Recent novel improvements have been the use of a universal testing machine (UTM) to record the force and calculate the work needed to separate a pre-compressed pair of individual cooked rice kernels, or to separate a single pre-compressed cooked kernel from the flat surface to which it is attached, while accounting, in both cases, for the contact areas. It is proposed to modernize an older manual method to measure the attractive force between two uncompressed cooked rice kernels directly with a tensiometer by replacing it with a UTM and expressing the result in term of a cohesion index, the dimensionless ratio between the net separation force and an individual cooked kernel’s weight. Rough calculations based on published data indicate that cooked rice of cultivars known to be sticky would have an index on the order of 15 while those known as non-sticky about 3 only, where the actual values will depend on the cooking procedure and the dry rice’s history. Also proposed is a similar adhesion index to characterize the attractive interaction of cooked rice with any surface of interest. Keywords Rice . Stickiness . Texture profile analysis (TPA) . Cohesion . Adhesion
Introduction Cooked rice texture in general and stickiness in particular have been of great interest to consumers and hence to geneticists, growers, and processors. Thus, the technical literature on the subject has numerous reports on what affects cooked rice stickiness, notably its variety (cultivar) which determines its starch compositions and molecular structure, e.g., [1–8], and how it is influenced by processing and storage of the dry grains, and preparation method, primarily the amount of water and temperature, e.g., [7, 9–15]. There are also many reports on how rice “stickiness” has been evaluated sensorily and/or instrumentally, e.g., [2, 8–10, 14–24]. Many of the described instrumental methods to quantify rice stickiness can be considered variants of the instrumental texture profile analysis, also known by its acronym TPA. The concept of instrumental texture profiling and human * Micha Peleg [email protected] 1
Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA
mastication imitation by a testing machine was proposed in the pioneering works of Alina S. Szczesniak and her collaborators at the MIT and later at the
Data Loading...
