An analytical method that uses HPLC was developed to analyze residual praziquantel in game meats hunted in Hokkaido. Samples were initially extracted with acetonitrile/methanol and McIlvaine buffer containing EDTA. The impurities were removed from the extract by n-hexane partition and solid-phase column. After removing the solvent, the extract was resolved in a 40% acetonitrile solution. Praziquantel in the purified solution was quantitatively determined using HPLC with a photodiode array detector (PDA). An interfering peak was not observed in chromatograms of game meat extracts, indicating the high selectivity of this method. Method validation was performed by recovery tests at the maximum residue limit concentration to evaluate the trueness, repeatability (RSD_r), and with-in laboratory reproducibility (RSD_wr). The validation results exhibited sufficient recovery (range, 84-91%) and precision (RSD_r ≦ 6% and RSD_wr ≦ 12%). These values fulfilled the criteria for the validation guidelines for residual pesticide analysis in Japan. The limit of quantification of this method was 0.03 µg/g in game meats. The time required for the preparation of eight test sample solutions was less than five hours. This method can help inspect residual praziquantel in game meats hunted in Hokkaido.

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For the identification of various mushrooms regarding to food, it has been used to evaluate these morphologic and/or genetic decisions by these researchers and experts. However, these judgments require expertness and know-how on uncertainty approach as human error. In this study, we developed the deep learning contour HPLC method for the high-probability decision of various mushroom samples based on convolutional neural network (CNN). HPLC condition is TSKgel ODS-100V with 0.1% formic acid in water/acetonitrile at 1.0 mL/min and detectable 190-500 nm for contour chromatograms. The sample preparation was used of extraction with methanol. Contour chromatograms of extracted mushroom based on this HPLC measurement were transformed to NumPy form and replicated by 2D-image for CNN by Python. This result showed that accuracy is 94.9% (n=117, 13 kinds). Thus, it is useful that this novel approach with contour HPLC and CNN indicates the establishment of various natural components based on deep learning.

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Quantitative and qualitative analytical methods for withaferin A (WA) in dietary supplements containing ashwagandha were developed using ultra-high performance liquid chromatography with a photodiode array detector (UHPLC-PDA) and UHPLC-quadrupole-Kingdon trap mass spectrometry. Ultrasonic extraction was performed using methanol as the extraction solvent. A reversed-phase C18 column was used for quantitative and qualitative analyses with UHPLC. The mobile phase for quantitative analysis was 0.1% (v/v) phosphoric acid solution-acetonitrile, while 0.1% (v/v) formic acid solution-acetonitrile was used for qualitative analysis. Results of the recovery test at the limit of quantitation (10 μg/g) and 10 times the limit of quantitation (100 μg/g) showed a recovery rate of 99.2% and 100.3%, respectively. Further, the relative standard deviation value of the repeatability and intermediate precision were each less than 3%, indicating good precision. When the developed method was applied to a commercial product, the form of the supplement that exhibited the highest WA content among the samples studied was capsule, and WA was detected with 6.52 mg in the capsule. The daily intake of WA was estimated to be 13.04 mg when the capsule product was consumed according to the product label recommendation. Qualitative analysis confirmed the presence of WA in all 15 health food products containing ashwagandha, as the retention times and product ion spectra of all 15 products were consistent with those of the standard solution.

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In today’s Japan, many individuals live in what is known as a stress society, where daily stress has become a common occurrence. The causes of stress vary from person to person and may be attributed to factors such as social environment and human relationships. Excessive stress can result in oxidative stress, which can have significant impact on both the mind and body. In fact, severe stress can lead not only to sleep disorders such as insomnia but also to mental illnesses such as depression. Theanine, a component derived from glutamic acid and ethylamine found in the roots of tea plants, is present in green tea and contributes to its umami taste. It has been approved as a functional food for stress and sleep. Theanine is known for its relaxing effects and its ability to improve sleep quality. Studies have also indicated its effectiveness in treating mental illnesses such as schizophrenia and depression. By understanding the functionality of theanine and investigating tea-based beverages that can be ingested most efficiently, it is believed that we can contribute to the prevention of diseases associated with reactive oxygen species generated by stress. In this study, we first evaluated the antioxidant effects of theanine using electron spin resonance (ESR) equipment. Next, we measured the amount of theanine in tea beverages using a liquid chromatograph/fluorescence detector (LC/FL). The ESR results demonstrated that theanine exhibits antioxidant activity by inhibiting the generation of reactive oxygen species through copper ions. Moreover, we found that Camellia sinensis, represented by green tea and black tea, contains a significant amount of theanine.

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In our previous study, three unknown plasticizers were detected in five polyvinyl chloride (PVC) toys on the Japanese market. In this study, we isolated these three plasticizers (1–3), and their structures were determined using accurate mass and nuclear magnetic resonance (NMR) spectral data. One of the plasticizers was identified as bis(2-propylheptyl) phthalate (DPHP). The others were assumed to be (4-methyl-2-propylhexyl)(2-propylheptyl) phthalate and bis(4-methyl-2-propylhexyl) phthalate. This is the first study to detect these phthalic acid esters in PVC toys in Japan. Isolated DPHP was subjected to quantitative NMR (qNMR). Using the NMR solution with the absolute concentration as a calibrant, the DPHP concentration in five PVC toys was then determined by GC/MS. The amount of DPHP ranged from 14.5–21.9wt%, whereas the DPHP level in one of the PVC toys was below the quantification limit (0.05wt%).

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The Japan Flavor & Fragrance Materials Association (JFFMA) conducted a survey on flavoring substances used in Japan from January to December 2020 in line with the global poundage survey conducted by the International Organization of Flavor Industry (IOFI) every five years. The results of the latest survey on the poundage of food flavoring substances are reported here. The 2020 flavoring substance count in Japan was 1,843, and the total poundage was 1,272 tons. It was generally confirmed in the current poundage survey that “a small quantity of a wide variety of flavoring substances” is used. Furthermore, for newly designated flavoring substances, the estimated intake was equal to or less than the acceptable intake for the concerned structure class or there was a sufficient margin between the estimated intake and the no-observed-adverse-effect level (NOAEL), confirming its safe usage.

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Objective In the current study, we aimed to evaluate the safety of excessive intake of a dietary supplement containing Proteoglycan complex 80, derived from salmon nasal cartilage.
Methods This randomized, double-blind, placebo-controlled, parallel-group study enrolled 30 participants (39.5±9.7 years [mean±standard deviation]) who ingested a dietary supplement containing 200 mg of Proteoglycan complex 80 or placebo for four weeks. General blood and urine biomarkers for health and medical conditions were analyzed at 0, 2, 4, and 6 weeks.
Results There were no clinically relevant changes related to the test supplement. Furthermore, there were no side effects related to the intake of Proteoglycan complex 80.
Conclusion Our findings demonstrated the safety of excessive intake of the dietary supplement containing Proteoglycan complex 80 derived from salmon nasal cartilage.

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An analytical method using HPLC was developed to analyze residual oxytetracycline (OTC) in apple juices. Residual OTC was extracted with a citrate-phosphate buffer containing EDTA-2Na. The matrix was removed from the extract by a solid-phase column, InertSep PLS-2 (265 mg/20 mL). After removing the solvent, the extract was resolved in a potassium phosphate solution. OTC in the test solution was determined quantitatively using HPLC with a photodiode array detector (PDA). The interfering peaks were not observed in chromatograms of blank extracts, indicating the high selectivity of this method. The limit of quantification of this method was 0.01 µg/g in apple juices. Method validation was performed by recovery tests at 0.2 µg/g to evaluate the trueness, repeatability (RSD_r), and with-in laboratory reproducibility (RSD_wr). The validation results for two types of apple juice exhibited sufficient recovery (99% and 85%) and precision (RSD_r ≦ 4% and RSD_wr ≦ 5%). The time required for the preparation of eight test solutions was less than three hours. This method can help inspect residual OTC in apple juices.

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Most edible mushrooms are grown in mushroom beds, but reusing the waste beds after cultivation is difficult, and they are often discarded. Therefore, developing a use for waste beds would be beneficial. The waste beds after mushroom cultivation contain syringic acid (SA) and vanillic acid (VA), which are phenolic compounds with anti-inflammatory and antioxidant activities. This study quantified SA and VA in mushroom beds cultivating Lentinula edodes (KX-S055 and XR-1) and Hypsizygus marmoreus (KX-BS023 and KX-BS025). The SA and VA amounts in the mushroom beds gradually increased after inoculation, indicating that SA and VA were produced during mushroom cultivation. In vitro, SA and VA were produced from the reaction between the wood component, lignin, and the waste bed protease extracts. These results suggest that SA and VA were produced by lignin degrading from mushroom proteases.

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27 巻3 号p141-148 に掲載の以下の論文について一部加筆訂正する。

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