Evaluation of solid state of rice flours produced by different milling processes using ATR-FTIR spectroscopy.

This study evaluated the influence of the milling process on solid state of rice flours according to water activity using ATR-FTIR. A band at 1740 cm-1 attributed to the C=O stretching of lipids was detected for crystalline samples, and it disappeared at a high aw range. The CH band at 2930 cm-1 of crystalline samples gradually shifted to a higher wavenumber with aw. This band of the α-formed and wet-milled samples shifted to higher wavenumbers above 0.8aw. A band due to OH stretching mode in the 3500-3000 cm-1 region did not shift with aw. The result obtained from IR spectra suggests that the parameter K calculated by Guggenheim-Anderson-de Boar model reflected not only the interaction between water molecules but also the changes of state in solids. Consequently, the results from this study provide insights about the adsorption properties of nonideal solids such as rice flour.

Phenomenological analysis on whipping behavior of rice flour batter.

In this study, the bubbles in rice flour batter were investigated under a constant temperature, because the bubble size distribution is important for the control of food texture. We obtained experimental data using a hand mixer and compared the properties of doughs prepared using six rice flours; each flour was prepared through a different milling process. We also added the size effect of the rice flour particles as the Bond number. Furthermore, we performed a dynamic wettability test to estimate the wettability of the rice flour surface. The results of this test were described well by the Washburn equation, and dc cosθ/dp was calculated as a wettability parameter (where, dc = effective diameter of a capillary in a powder bed, cosθ = the contact angle, dp = mean particle diameter of rice flour). If bubble sizes depend mainly on the inertial force, viscous force, surface tension, and gravity, then the normalized mean bubble diameter should be a function of the Reynolds number, Weber number, and Froude number. The mean bubble diameter (dbm ) generated by whipping was expected to be affected by the thickness (d) of the rod of the mixer, its movement speed, and physical properties of the material. Therefore, dimensionless mean diameter (dbm /d) was expressed based on a dimensionless equation. In the three-phase dispersion, different empirical equations were obtained depending on the amount of rice flour added, and the bubble diameter could be predicted using dimensionless parameters. In addition, the equations were generally applicable to the various materials selected for this study. PRACTICAL APPLICATION: The powder properties of rice flour were investigated, and dimensionless parameters were analyzed to construct an appropriate process control system for rice flour-based food products. Although the process method optimized for flour products is also used for rice flour products in practical situations, the comprehensive evaluation based on dimensionless parameters leads to optimization of the process for rice-flour based products. Moreover, this optimization might strongly support the creation of a new texture, and thus, the potential for market expansion of rice-flour based products is considerable.

Ultramorphological evaluation of the dentin acid-base resistant zone of two-step self-etching systems after long-term storage in water.

PURPOSE: To evaluate the morphological changes in the acid-base resistant zone (ABRZ) at the resin/dentin interface after long-term storage in water. MATERIALS AND METHODS: Two-step self-etching adhesive systems, Clearfil SE Bond (SE) and Clearfil Protect Bond (PB) (Kuraray Medical) were used. Human dentin disk sandwiches with resin composite were prepared, sectioned, and embedded in epoxy resin. The specimens were stored in water for 1 day, 1, 3 or 6 months, and then subjected to demineralizing solution and 5% NaOCl. The specimens were finally sectioned again, polished, argon-ion etched, and observed with SEM. RESULTS: The outer lesion (OL) thickness at 1 day ranged from 10 to 15 µm but increased to approximately 30 µm after 6 months, suggesting gradual loss of dentin stored in water. A lower electron density was noted in the adhesives at the locations that were exposed to water. The ABRZs were observed clearly in all groups; the thickness of the ABRZ at the mid-point of the OL gradually decreased with time for SE. For PB, the thickness was stable up to 1 month, but decreased after 3 months. The bottom of the ABRZ in SE formed a right angle with dentin; in contrast, in PB, it sloped down toward dentin with a broadening bottom. CONCLUSIONS: Water storage resulted in changes both in the dentin substrate and the adhesive layer. An ABRZ was observed beneath the hybrid layer after long-term storage in water in both SE and PB. The ABRZ was thicker and relatively more stable in PB, probably due to fluoride release.

Effect of functional monomers in all-in-one adhesive systems on formation of enamel/dentin acid-base resistant zone.

This study aimed at evaluating the effect of functional monomers in all-in-one adhesive systems on formation of acid-base resistant zone (ABRZ) in enamel and dentin. Experimental adhesive systems containing one of three functional monomers; MDP, 3D-SR and 4-META were applied to enamel or dentin surface and light-cured. A universal resin composite was then placed. The specimens were subjected to a demineralizing solution (pH 4.5) and 5% NaClO for acid-base challenge and then observed by SEM. The ABRZ was clearly observed in both enamel and dentin interfaces. However, enamel ABRZ was thinner than dentin ABRZ in all adhesives. Morphology of the ABRZ was different between enamel and dentin, and also among the adhesives. Funnel-shaped erosion was observed only in the enamel specimen with the 4-META adhesive. The formation of enamel/dentin ABRZ was confirmed in all adhesives, but the morphology was influenced by the functional monomers.

Early phase metabolic bone disorders after gastrectomy: influence of active vitamin D treatment.

Metabolic bone disorders are recognized as one of the late complications after gastrectomy. However, the onset time and the extent of bone disorders are still unknown. We examined the influence of active vitamin D treatment on bone metabolism in the early period after gastrectomy. Sixty-three postgastrectomy patients were divided into two groups; active vitamin D treatment group [VD(+)] and no treatment group [VD(-)]. The level of serum calcium and phosphate was increased in the VD(+) group compared with the preoperative level, and parathyroid hormone (PTH-M) was decreased in the VD(+) group. Both 1,25-(OH)2D3 and bone-specific alkaline phosphatase (B-ALP) were increased in the VD(-) group. Cross-linked carboxyterminal telopeptide of type I collagen (I-CTP) was increased in the VD(+) group. There was no change in calcitonin in either group. In conclusion, metabolic bone disorders after gastrectomy have their onset in the early period, and active vitamin D treatment from the early period may be effective in preventing bone disorders.