NMR imaging of the wheat grain cooking process

Abstract

NMR imaging has been used to study the boiling and steaming of intact wheat grains by mapping the distribution of water on the central cross section of grains after various cooking times. The results show different distributions of water occurring with boiling and steaming. Boiled grains showed a front of moisture which gradually moved towards the centre of the grain, although some water was able to diffuse ahead of the front. Steamed grains showed no such front, but showed a homogeneous distribution of water which gradually increases with cooking time. The different results for boiling and steaming imply that different mechanisms control the influx of water in each case, and provide important data for modelling these processes. It is postulated that absorption of water during steaming is slowed by the grain temperature rising above that of the steam temperature as a result of the latent heat associated with the condensation of steam being taken up by the grain.

Water status of cooked white salted noodles evaluated by MRI

“…MRI is pretty well regarded as a powerful tool for characterizing water mobility and distribution of foods during processing and storage (Fukuoka, Mihori, & Watanabe, 2000;Kojima et al, 2001;Ruan & Chen, 1998;Stapley, Hyde, Gladden, & Fryer, 1997;Takano, Ishida, Koizumi, & Kano, 2002;Takeuchi, Fukuoka, Gomi, Maeda, & Watanabe, 1997). Although, the texture of boiled WSN evaluated by many objective measurements, such as a texture analyzer equipped with several of probes, has been reported in many works (Guan & Seib, 1994;Oh, Seib, Deyoe, & Ward, 1983;Yun, Rema, & Quail, 1997), little information is available on the relationship of water status and texture changes of cooked WSN during storage.…”

Swelling and erosion affecting flavor release from glassy particles in water

“…Using NMR, it has been proven that the waterfront in wheat grains moves approximately linearly with time in wet conditions (Stapley, 1995;Stapley et al, 1997). If this is true for natural particles such as whole-wheat grains (Landman, 1999) and for rice grains (Takeuchi et al, 1997a,b), this may also be expected for glassy maltodextrin particles.…”

MR imaging and diffusion studies of soaked rice

“…For example, microscopic methods such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are typically used to identify the structure and histology that contribute to the textural properties of rice (Kim, Kang, Hwang, Kim, & Choi, 2004;Ogawa, Glenn, Orts, & Wood, 2003). Magnetic resonance (MR) imaging has been used to noninvasively determine moisture distribution and mobility, and to visualize internal structures in corn kernels during steeping (Ruan, Litchfield, & Eckhoff, 1992), in wheat grain during boiling and steaming (Stapley, Hyde, Gladden, & Fryer, 1997), and in rice during cooking (Horigane et al, 1999;Kasai, Lewis, Ayabe, Hatae, & Fyfe, 2007). However, these studies do not mention the contributions of lipids to the proton density in MR imaging measurements.…”