Hyung-Soon Kim

Physico-chemical confinement of helical nanofilaments

Helical nanofilaments (HNFs) have attracted much interest because of their unique optical properties, but there have been many hurdles to overcome in using them for the practical applications due to their structural complexity. Here we demonstrate that the molecular configuration and layer conformation of a modulated HNF (HNFs(mod)) can be studied using a physicochemical confinement system. The layer directions affected by the chemical affinity between the mesogen and surface were drastically controlled in surface-modified nanochannels. Furthermore, an in situ experiment using grazing-incidence X-ray diffraction (GIXD) was carried out to investigate in detail the structural evolution through thermal transitions. The results demonstrate that the HNF(mod) structure can be perfectly controlled for functional HNF device applications, and a combined system with chemical and physical confinement effects will be helpful to better understand the fundamentals of soft matter.

Quality Characteristics and Antioxidant Activity of Yogurt Added with Whole Barley Floura

Department of Environmental & Chemical Engineering, Seonam UniversityAbstract In this study, a yogurt containing skim milk powder and whole barley flour was fermented with lactic acidbacteria, and its quality and properties were estimated. The yogurts with 1% and 3% barley flour had lower pH values,higher titratable acidity, and higher Brix values than the control. In addition, the viable cell counts were lower andviscosity was higher. The value of L was low, and the values of a and b were high. The yogurt with 3% barley flourhad more lactic acid than the control and showed a substantial increase in the amount of acetic acid. β-Glucan contentand antioxidant activity increased with the amount of barley flour added. In sensory evaluation, there was a similarpreference for the yogurt with 3% barley flour and the control, and as the barley flour content increased, the preferencedecreased. Moreover, the preference for the yogurt was higher among old people.Keywords: yogurt, whole barley flour, β-glucan, sensory evaluation

Quality Characteristics of Whole Barley Flour Added Yogurt Made with Various Lactic Acid Bacteria

The objective of this experiment was to select the best strain of lactic acid bacteria for the manufacture of yogurt with 3% whole barley flour. Yogurt was fermented with various lactic acid bacteria, Lactobacillus acidophilus (LA), Lactobacillus delbrueckii subsp. Bulgaricus (LB), and Streptococcus thermophilussei (ST), and quality properties, βglucan content, and antioxidant activity were estimated. The quality of the control yogurt and that containing barley flour showed significant differences according to the type of lactic acid bacteria strain. Barley yogurt that was fermented with LALBST complex bacteria had low pH, high titratable acidity and brix. Also, its viable cell count, the value of L, and antioxidant activity were high, and the value of a and b were low. The β-glucan content of barley yogurt containing 3% whole barley flour was 0.15%. The pH of yogurt decreased with the addition of barley flour. Titratable acidity, brix, β-glucan content, and the antioxidant activity of yogurt fermented with barley flour increased. Viscosity also increased significantly with the addition of barley flour. Yogurt qualities such as pH, titratable acidity, and viscosity were developed by the addition of barley flour. From these results, the best strain of lactic acid bacteria for fermenting yogurt containing barley flour was the LALBST complex.

2.61 – Metabolic Control

Understanding metabolic control is an important facet of manipulating metabolic pathways. It has been well documented that simple removal of competing pathways and regulatory effects results in limited success. More often than not, such modifications result in no change or an effect that is less beneficial than predicted. Control analysis provides a quantitative analysis of the system allowing us to better understand how systems respond to various perturbations. Consequently, knowledge of the systems response to perturbation allows us to target specific elements for modification so that the desired response is obtained. This article will focus on the various approaches developed for metabolic control as well as experimental approaches developed to obtain data for computational analysis. With full understanding of the dynamics of metabolic control, a successful manipulation of the metabolic flux and metabolite concentrations can be achieved.