To verify the presence of yohimbine and its four stereoisomers (corynanthine, α-yohimbine, β-yohimbine, and isorauhimbine)
in health food and to perform a quantitative analysis, we examined the separation and detection conditions for each component
by GC-MS and LC-UV-MS. As a result, in GC-MS analysis, baseline separation of all five components (yohimbine and its four
stereoisomers) was achieved with a mid-polar column. However, the presence of a water desorption peak due to heating, calibration
curves with poor linearity, and low recovery rates suggested that the use of GC-MS for quantitative analysis required further
consideration. On the other hand, in LC-UV-MS analysis, baseline separation of all the five components was possible when a
mixture of ammonium bicarbonate buffer and acetonitrile was used as the mobile phase. In addition, calibration curves showed
adequate linearity with good recovery rates. On the basis of these results, we decided to employ the analytical condition by LC-UVMS.
Using this method, we analyzed commercial health food to determine the actual contents of yohimbine and its stereoisomers,
and identified food products in which only yohimbine was detected, as well as those in which yohimbine and its four stereoisomers
were detected. Furthermore, we found at a high frequency food products in which corynanthine and α-yohimbine were detected at
higher concentrations than yohimbine.
In this study, the relationship between the catechin content and antioxidant capacity of the tea extract, a natural food additive,
was investigated to establish the quality standards based on the antioxidant capacity. The antioxidant activity was evaluated by
1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The antioxidant capacities were detected in 13 kinds of tea extracts among the tested
14 kinds of them. A correlation was found between the total amount of catechins (C, EC, GC, EGC, Cg, ECg, GCg, and EGCg) and
the antioxidant capacity (r = 0.975, n = 13, p ‹ 0.01). In addition, the contribution ratio of all kinds of catechins in the tea extract
to the antioxidant capacity was 90%. These results suggest that the DPPH assay is a useful method to evaluate the antioxidant
capacity in the tea extract for establishing the quality standards.
Ginger has been reported to show many health enhancement effects. We prepared a hexane extract of raw ginger (HRG) under
low temperature, and examined its anti-obesity effects using 3T3-L1 cells. HRG promoted adipocyte differentiation in a dosedependent
manner and enhanced the expression levels of adipocyte-specific genes, such as adiponectin and Glut4 . HRG also
exhibited peroxisome proliferator-activated receptor γ ligand activity, similar to antidiabetic drug thiazolidinediones, which
promoted adipocyte differentiation and increased small adipocytes. In addition, HRG showed a tendency to suppress the action
of tumor necrosis factor-α, which causes insulin resistance by downregulating the expression of adipocyte-specific genes. These
findings suggest that HRG would be utilized as a functional food material for the prevention of obesity and related diseases by
increasing small adipocytes.
Octanoic acid (OA) is an ingredient of peracetic acid-based sanitizers (PAS), which are widely used in the sanitation of uncooked
food. Since, OA can remain on PAS-treated foods, we developed a simple analytical method to determine OA levels in uncooked
foods. The developed method involves straightforward solvent extraction with diethyl ether, derivatization with sulfuric acid/
methanol and gas chromatography coupled with mass spectrometry. The recovery and relative standard deviation of OA ranged
from 74.2 to 96.6% and 2.6 to 9.6%, respectively. The limit of quantification (LOQ) in foods was estimated to be 0.02 mg/kg.
We applied the developed method to imported uncooked foods (56 beef samples, 34 vegetable samples and 89 fruit samples), and
found that OA levels ranged from 0.34 to 0.53 mg/kg, the LOQ to 0.48 mg/kg and LOQ to 1.12 mg/kg, respectively. Most of the
determined OA in imported uncooked foods could be considered to be derived from OA naturally contained in the foods.
Bilberry fruit extracts have been used as herbal medicines for the treatment of vascular and vision disorders in Europe, whereas
they are only used in health food products in Japan. In April 2015, “Foods with Functional Claims (FFCs)” was established as a new
category of voluntary labeling in health food products sold in Japan, and several bilberry-containing products have been submitted
as FFCs. To ensure the efficacy and safety of the FFCs, effective quality control on the original plants, consistent composition, and
manufacturing process is important for the herbal ingredients with specific health-related functions. In this study, we evaluated
the quality and quantity of 5 FFCs whose functional substances are bilberry anthocyanins. Twenty compounds (15 anthocyanins
and 5 anthocyanidins) in the FFCs were separated by the HPLC method according to the European Pharmacopoeia instead of the
journal featuring dietary supplements. Cyanidin-3-rutinoside was detected in 3 FFCs containing black currant extracts as well as
bilberry extracts, and the anthocyanins in these FFCs were considered to be derived from both plants. Since the bilberry extracts
are the active ingredient with pharmaceutical evidence and its health benefits are displayed on the product’s packaging, the proper
regulation for ensuring a consistent quality of bilberry-containing FFCs would be recommended.
A newly isolated yeast strain, Pseudozyma hubeiensis 31-B, produced an extracellular carboxypeptidase but no detectable
proteinase activity. The carboxypeptidase was purified from filtered culture medium by ammonium sulfate precipitation and
successive four column chromatography steps: TOYOPEARL DEAE-650M, TOYOPEARL Butyl-650M, hydroxylapatite, and
TOYOPEARL HW-55 chromatography. The final enzyme preparation appeared homogeneous on SDS-polyacrylamide gel
electrophoresis. The enzyme had a molecular mass of 70.5 kDa. The optimum temperature and pH of the purified enzyme were
approximately 50°C and 5.0, respectively. The purified carboxypeptidase preferentially hydrolyzed Z-Phe-Leu, and its activity was
inhibited by diisopropyl fluorophosphate. The carboxypeptidase produced by P. hubeiensis 31-B has potential applications in the
food industry as a food additive.