Deoxyribonucleic acids (DNAs) in dried fruit products were examined for detectability using real-time polymerase chain reaction (PCR). Endogenous genes with low copy numbers in Carica papaya L. (papaya), Solanum lycopersicum L. (tomato) and Malus domestica (apple) genomic DNAs, i.e., Chymopapain, LAT52 and Apo 5, respectively, were targeted for detection in dried fruit products that were processed with and without food additive sulfites as a bleaching agent, preservative or antioxidant. A total of 13/14 dried papaya, 8/8 dried tomato and 3/3 dried apple products that were processed with sulfites were not detected under a Cq value of 40 in a duplicate real-time PCR test. Despite their undetectability, endogenous 18S rDNA with high copy numbers in the genomic DNA of these fruits was detected at approximately the same amplicon size as the endogenous genes with low copy numbers. Furthermore, BAN, a single-copy endogenous gene found in all dried Musa acuminata (banana) products, was detected using a 50 ng DNA template at a Cq value of 22.33–35.80 regardless of whether the fruit was processed with or without sulfites. Although the dried fruit products that were processed with sulfites may contain DNAs, the yields of extracted and purified DNAs were reduced to the degree that not all endogenous genes could be detected reliably using real-time PCR. This may affect the reliability of real-time PCR testing for detecting specific ingredients in dried fruit products, such as genetically modified fruit and food allergens.

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Commercially available powdered protein drinks have different protein materials and formulations depending on their purpose. It is generally believed that the digestion and absorption rates of whey protein are fast, while those of soy protein are slow. However, there is no scientific evidence to support these claims. In this study, we examined the differences in digestibility between whey protein and soy protein, which are raw materials for protein drinks, using a technique for the in vivo catheterization of the portal vein in rats, which allows direct measurement of digested and absorbed amino acids. A whey protein suspension or soy protein suspension prepared to a total nitrogen content of 1.125 g/100 mL was administered to rats at 15.0 mL/kg, and the concentration of free amino acids in portal vein blood was measured over time. The results showed that the absorption levels of essential amino acids, such as valine, leucine, and isoleucine, were significantly higher with the whey protein than the soy protein. In contrast, the absorption levels of non-essential amino acids, such as asparagine and arginine, were significantly higher with the soy protein than the whey protein. In addition, a comparison of the digestion and absorption rates revealed that whey protein was digested and absorbed significantly faster than soy protein. This study successfully demonstrated scientifically that the types of amino acids supplemented and the rates of digestion and absorption differed depending on the protein used in protein drinks, i.e., whey protein or soy protein.

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Vitamin E is a fat-soluble component that has an antioxidant effect in the body, and there are many research reports on the physiological functionality of α-tocopherol. In recent years, however, it has been reported that γ-tocopherol also has various physiological actions such as a diuretic action and a urinary sodium excretion promoting action. In this study, in order to confirm a urinary sodium excretion promoting effect of γ-tocopherol in long-term dietary intake, we prepared canola oil containing high γ-tocopherol, and investigated urine volume, urinary sodium excretion, and blood biochemical test value in high-salt diet (5-8% NaCl diet) Sprague-Dawley rats administered continuously high γ-tocopherol oil for 28 days. As a result, on day 15, the urine volume of high γ-tocopherol oil administration group increased significantly (p <0.05) as compared with the control group. On day 15 and 22, the urine sodium excretion of high γ-tocopherol oil administration group seemed increased significantly (p <0.05) as compared with the control group, however, food intake was also significantly increased (p <0.05) compared to the control, resulting in a correlation between sodium intake and excretion. Therefore, in this study, we could not observe the urinary sodium excretion promoting effect of administered continuously high γ-tocopherol oil, but an increased urine output. In addition, as a result of blood biochemical test after the end of administered continuously, the blood glucose level of high γ-tocopherol oil administration group was significantly (p <0.01) lower than that of the control. Since the blood glucose level decreased and the difference of tocopherol content observed in the liver, it may be considered the possibility that the increase of γ-tocopherol in the blood affected the glycolipid metabolism due to the continuous intake of γ-tocopherol.

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The objective of this study was to prepare acceptable banana jam as one of the processed foods using fully ripened banana fruits and to elucidate its physicochemical and sensory properties for further applications. The optimal condition for preparation of banana jam was as follows: moisture content, 80%; Brix%, 50; acidity, 0.4%, added amount of pectin, 0.5%, respectively. The color of the tested jam was pale yellow as well as that of the fruit flesh. By sensory analysis, the tested jam had good flavor, smoothness, fleshiness, and strong sweetness when compared with those of commercially available banana jams. Low sugar content jam that makes use of the characteristics of fully ripened banana fruits is attuned to the needs of the consumers. Therefore, banana jam may contribute to the application in jams and its related industries as one of the effective utilization of fully ripened banana fruits.

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A rapid and easy method for determination of antibacterial substances in processed foods manufactured from livestock and marine products using high performance liquid chromatograph with photodiode array detector (HPLC-PDA) has been developed. Residual antibacterial substances were extracted with a mixture of acetonitrile/methanol and citrate-phosphate buffer. The lipids were removed from the extract by acetonitrile-hexane partition and solid-phase column. After removal of the solvent, the extract was resolved in potassium phosphate solution and analyzed with HPLC-PDA. Recovery tests of 8 major antibacterial substances from processed foods were performed, and all substances exhibited acceptable recoveries (70-120%) with low relative standard deviations. The time for sample preparation with 8 samples to test solutions was approximately 6 hours. This method could be useful for primary screening inspection of residual antibacterial substances in processed foods manufactured from livestock and marine products.

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An enzyme-linked immunosorbent assay (ELISA) is widely used to test for allergens in foods. In this study, we investigated how temperature affects the performance of the “Morinaga FASPEK ELISA II Egg” from the kit under different conditions. ELISA was performed under low-temperature conditions (approximately 5°C), room temperature conditions (approximately 20–30°C), high-temperature conditions (approximately 45°C), and ultra-high-temperature conditions (approximately 65°C). The absorbance values were measured and compared for all conditions. Our results showed that compared to the absorbance at room temperature, the absorbance showed an average decrease of 44.5% and 15.7% under low-temperature and high-temperature conditions, respectively. A calibration curve could not be established under ultra-high-temperature conditions. To verify the main factor contributing to the decrease in absorbance, especially under high-temperature conditions, ELISA was carried out by independently heating the antigen in the standard egg product, the antibody on the immobilised plate, and the enzyme-labelled antibody solution from the kit to high-temperature conditions. No decrease in absorbance was observed upon heating the standard egg product alone. However, an average decrease of 6.2% and 1.7% was observed upon heating the antibody-immobilised plate alone, and heating the enzyme-labelled antibody solution alone, respectively. Therefore, while performing ELISA, it is important to control the temperature in the laboratory, especially that of the antibody-immobilised plate.

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