Antibacterial activities of the major phenolic components from Camellia sinensis L. were investigated against several pathogenic microorganisms including Gram-positive strains like Staphylococcus aureus ATCC 29213 and Streptococcus pyogens 308A; and Gram-negative strains like Escherichia coli ATCC 25922, Escherichia coli 078, Pseudomonas aeruginosa 9027, and Enterobacter cloacae 1321E. The MIC values demonstrate that both (-)-epicatechin and (-)-epigallocatechin were more considerably toxic against Staphylococcus aureus ATCC 29213 than the other two catechins like (-)-epicatechingallate and (-)-epigallocatechin-3-gallate. (-)-Epicatechingallate and (-)-epigallocatechin-3-gallate were most inhibitory against Escherichia coli ATCC 25922. As a result, (-)-epicatechin showed predominant antibacterial activities among tea varieties. The contents of major polyphenolic components such as four catechins, theaflavin, and quercetin were different according to fermentation processes. The total contents of four catechins were ranged from 13.81 to 1.33%, with (-)-epigallocatechin-3-gallate being dominant among tea varieties; theaflavin was found the characteristic pigment in fully-fermented black tea.

Hydrolysis and absorption properties of submicron-(below 1 lm) and micron-sized (over 100 lm) powders of raw rice, heat-gelatinized rice, fermented rice and wheat were investigated in vitro and in vivo. Nutrient content such as protein, carbohydrate or vitamin C in the samples was not different significantly between submicron-and micron-sized powders, but it showed difference according to processed type of the powders. Submicron-sized powders were hydrolyzed more easily than micron-sized powders by a-amylases such as industrial, human salivary and porcine pancreatic a-amylase but not by a-glucosidase in all the tested samples. Patterns of blood glucose change were investigated in rats. The highest glucose levels were obtained at 30 min after oral administration in both submicron-and micron-sized powders, but the levels were decreased drastically in groups administered submicron-sized powders, while they were slow and gradual in groups administered micron-sized powders. On the contrary, the body weight gained and food efficiency ratios showed a tendency to be decreased slightly in mice fed with submicron-sized rice powders compared to those with micron-sized rice powder.

Systematic study of how different drying methods, namely hot-air drying, vacuum-drying, and freeze-drying, affect color, browning index, degree of rehydration, water solubility, and vitamin C content is critical for utilizing pine needle powders (PNP) as a novel ingredient in functional foods. Samples prepared by vacuum-drying showed a significantly higher L*-value, whereas higher a*- and b*-values were detected in the hot-air dried samples (P<0.05). The browning index was significantly higher in samples prepared by vacuum-drying compared to samples prepared by freeze-drying (P<0.05). Freeze-dried PNP exhibited a significantly higher degree of rehydration than hot-air dried samples (P<0.05). Water solubilities of freeze-dried and hot-air dried samples were significantly higher than that of vacuum-dried sample (P<0.05). Vitamin C was less destroyed during freeze-drying compared to hot-air or vacuum-drying (P<0.05). Freeze-dried samples displayed a clear porous structure and appeared to have a bigger space, whereas hot-air dried samples showed lower porosity than vacuum and freeze-dried samples.

No abstract

Korean pine needles have long been used in traditional Korean herbal medicine. Hence, pine needle extract was prepared as powder using 50% ethanol extraction followed by various drying methods such as hot-air drying, vacuum drying, and freeze drying. With these extracts, the effects of the drying methods on the total phenolic content and antioxidant activities were assessed. As a result, vacuum drying resulted in the highest yield, whereas hot-air dried extract contained the least amount of total phenolic compounds. However, the extracts by hot-air drying showed the highest amount of total flavonoids in comparison with the extracts obtained by other drying methods (p<0.05). In case of freeze dried samples, there was much stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities than in other samples (p<0.05). The nitrate scavenging activities of all samples at high acidic conditions were higher than 80%, and that of the vacuum dried sample showed a significantly higher value (p<0.05). t-Cinnamic acid was the major phenolic acid regardless of drying method applied.