Hyun-Yu Lee

Effects of air, microwave, and microvacuum drying on brown rice quality

Proper hulling and drying are critical components of brown rice quality. Two medium grain rice varieties were examined for grain qualities including husking, cracking, germination ratio, color, hardness, and fat acidity after drying with 15, 30, and 45°C air, as well as at 100 and 200 W microwave, and microwavevacuum, respectively. Unlike impeller dehuller, rubber roller dehuller could not process rice with 22% moisture content. Brown rice varieties with 22% moisture content after dehulling were dried at 15, 30, and 45°C until moisture content reached 15%; the drying ratios for each temperature were 1.02, 2.55, and 3.46 %/h, respectively. When brown rice varieties were dried at below 30°C, no significant changes were observed in physico-chemical properties, whereas the cracking ratio increased significantly. Microwavevacuum drying resulted in higher reductions of germination ratio and fat acidity than with the microwave only at 100 W as well as reduced drying time over microwave drying.

Quantitative microbiological profiles of brown rice and germinated brown rice

Among health conscious people, brown rice (BR) and germinated brown rice (GBR) are increasingly more popular for consumption in Korea because their nutritional values are greater than those of ordinary white rice (WR). The overall microbial counts for BR were higher than those for WR and those of GBR were higher than those of BR. Interestingly, the lactic acid bacteria (LAB) counts in GBR increased markedly and their selected representatives were Weissella confusa, Pediococcus pentosaceus, and Lactobacillus fermentum. To our knowledge, this is the first attempt to enumerate and compare LAB loads on WR, BR, and GBR.

Anti-obesity and hypolipidemic effects of chufa (Cyperus esculentus L.) in mice fed a high-fat diet

This study was aimed to clarify the effect of defatted chufa (Cyperus esculentus L., DC) on diet-induced obesity and lipid metabolism in mice. C57BL/6J mice were fed 1 of 4 experimental diets for 7 weeks: a normal diet (N), a high-fat diet (HF), a high-fat diet with 5% DC (LDC), and a high-fat diet with 10% DC (HDC). DC supplementation (10%) significantly reduced body weight gain, adipose tissue weight, and adipocyte size increased by high-fat diet although there was no significant difference between HF group and LDC group. Serum total cholesterol and triglyceride levels of the HDC group were significantly decreased compared to those of the HF group. The hepatic triglyceride levels also decreased significantly with 10% DC supplementation, but not changed with 5% DC supplementation. Serum insulin and leptin levels in the LDC and HDC groups were significantly decreased compared to those of the HF group. These results suggest that defatted chufa may be useful for the prevention of diet-induced obesity and hyperlipidemia.

Amylolytic Activity of Brown Rice and Black Rice during Germination

Enzymatic activity in germinated cereal grains is important for the saccharification of starch materials. This study was conducted to investigate the amylolytic activities of germinating brown rice and black rice that have different amylose contents. Brown rice and black rice were steeped at room temperature for 24 h and germinated at 20 and 30 o C for 1, 2, and 3 days. α- and β-Amylase activities in normal brown rice increased very slightly during the 3-day germination period, but the enzymatic activities were slightly higher in low-amylose (waxy type) brown rice. Diastatic power (DP), a measure of starch-saccharifying enzyme, was higher in the germinating brown rice with low amylose than in those with normal amylose content. α- and β-Amylase activities in black rice increased gradually during germination, and DP of low-amylose black rice appeared to be higher than that of normal brown rice. Amylase activities in brown rice and black rice germinated at 30 o C were higher than those germinated at 20 o C. Compared to brown rice, the overall

Back End of the Line

Due to great benefits including excellent conformality and thickness controllability at atomic scale, atomic layer deposition (ALD) is being considered as a promising deposition technique, for sub-20 nm technology node logic device fabrication. Among various potential applications in logic device fabrication, the ability of ALD to deposit various metal and nitride films with high quality at low temperature makes it a viable deposition process for back end of the line (BEOL) process. First, transition metal deposition technique with extremely good conformality is required for silicide contact formation with low contact resistance. On top of the silicide contact, tungsten plug formation with very good gap filling property is required. Also, for Cu metallization, very thin and conformal deposition of diffusion barrier and seed layer is essential for good gap fill by electroplating. In this chapter, we will review the efforts on the application of ALD at BEOL process; including contact/plug formation and metallization.