S-Allyl-L-cysteine (ALC) is one of the bioactive compounds in garlic (Allium sativum) that is known to be good for human health. ALC, however, is found only in trace amounts in raw garlic bulbs, and the current method of accumulation is to soak garlic in aqueous ethanol for a long period (‘soaking’). We discovered a new method for accumulating ALC during our investigation of storage methods of garlic bulbs. Following the warming of garlic bulbs for up to 2 weeks in an oven or incubator (‘warming’), marked accumulation of ALC was observed. First, we determined that warming temperatures in the range of 45 to 75°C were effective with the optimal conditions being warming at 55°C for 2 weeks. Next, the current soaking method for ALC accumulation was compared to our new warming method. We found that the amount of ALC accumulated from garlic bulbs was influenced by whether the garlic bulbs were dormant or dormant-terminated. In dormant-terminated garlic bulbs, maximum accumulation was achieved by warming for 12 days at 45°C or by soaking (20% (v/v) aqueous ethanol) for 101 days at room temperature to obtain 3.3mmol or 1.5mmol per 100g dry weight, respectively. In dormant garlic, maximum accumulation was achieved by warming for 2 weeks at 55°C or by soaking for 91 days at room temperature to obtain 2.0mmol or 4.0mmol per 100g dry weight, respectively.

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As dietary trypsin inhibitors are thought to cause alteration in exocrine pancreatic function that results in increased energy expenditure, we investigated whether these inhibitors affect lipid metabolism in humans or experimental animals. Five-week-old male Wistar rats were fed experimental diets of a 20% casein control diet or trypsin inhibitor (TI) diets containing 0.2% Japanese quail ovomucoid or rice bran trypsin inhibitor for 3 weeks. Liver and serum lipids were measured and pancreata were collected for trypsin, chymotrypsin, and amylase assays. No significant differences were observed in feed intake and body weight gain between the control and TI groups. The TI groups had significantly lower serum triacylglycerol levels, yet no change in liver and serum cholesterol levels. Dietary TIs led to increased pancreatic weights and elevated trypsin, chymotrypsin, and amylase levels in the pancreata. These findings support our hypothesis that dietary TIs affect lipid metabolism. Moreover, we found that dietary TIs have a serum triacylglycerol-lowering function related to the increased pancreatic function.

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Dibenzoyl Thiamine (DBT), a lipophilic derivative of vitamin B₁, has been approved as a food additive in Japan. The use of DBT in a variety of processed food has increased recently due to the current consumer trend for “Vitamin-Rich” food products. However, there are no current methods that accurately measure the total vitamin B₁ in DBT-rich food due to the incomplete hydrolysis of DBT to thiamine. Although Takadiastase generally has been used for thiamine determination to liberate free-thiamine from its esterified forms, this incomplete hydrolysis of DBT causes underestimation of the total vitamin B₁ in processed food. Therefore, we added an alkaline-hydrolysis-step with NaOH to the Japanese official method for the nutritional food labeling to optimize the determination of total vitamin B₁. After dephosphorylation using Takadiastase and complete hydrolysis of DBT to thiamine in 0.49mol/L NaOH, total vitamin B₁ was determined by the post-column HPLC method combined with a column-switching system. Through examining more than 60 samples of processed food with or without DBT, no significant matrix effects were observed. The recovery test obtained a little over 90% recovery and around 2% RSD for more than 20 samples containing DBT. Based on these results, we propose a novel and single validated procedure for accurately measuring the total vitamin B₁ content in processed food regardless of DBT content.

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Migratory fish and birds have muscles rich in anserine to maintain posture and instantaneous power. The anti-fatigue activity of anserine was first determined by a forced-swimming test on mice. Here, we conducted exercise tolerance testing on physically normal men to evaluate the anti-fatigue effect of salmon muscle extract containing anserine (SEAns) in a clinical test. SEAns inhibited creatine phosphokinase activity, suppressed elevation of the cortisol level in blood, and improved exercise endurance. From these results, we conclude that SEAns reduces physical fatigue and mental stress.

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[in Japanese]

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