Foam produced using matcha is of great interest because it comprises gas and liquid forms, as well as a solid form. We investigated the foaming properties and foam stability of foam produced from matcha and measured the median diameter of the foam in terms of particle size. The results show that the foaming property is derived from conjoining of the matcha soluble ingredients and the matcha fine particles. Foam stability did not appear to be affected by differences in particle size or matcha concentration. However, the soluble ingredients did contribute to foam stability. The median diameter of foam did not change with the milling method or particle size of the matcha. Thus, the matcha particles localized along the foam membrane.

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This paper discusses the effect of three dehydration methods (vacuum drying, microwave drying and vacuum-microwave drying) on the physical properties of fresh-cut radish after freezing and after post-thaw rehydration in the dehydro-freezing technique. The physical properties, including electrical impedance, texture, re-hydration rate and micro-structure observation of the samples were observed under a microscope, and changes in L- ascorbic acid were investigated. The vacuum-microwave drying method was employed based on the finding that it had the least impact on the physical properties and loss of L-ascorbic acid after freezing and after post-thaw rehydration. The thawing and rehydration process was carried out by immersion in water at 40°C, which inhibited surface hardening and presented the possibility of restoring the semicircular Cole-Cole plot.

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Low fat processed cheeses were prepared with variable fat content while holding water content constant using two natural cheeses having different fat content. These physical properties of the processed cheeses were evaluated by sensory and instrumental analyses. The effect of whey protein concentrate (WPC) addition on the physical and formation structure of low fat processed cheeses was investigated. The use of WPC as a fat replacement was also examined. The sensory hardness of processed cheeses increased with decreasing fat content. Likewise, the maximum load in the compressive test showed the same pattern. Scanning electron microscope (SEM) observation of the cheese finer network structures for higher WPC content. Comparison of the addition of two WPCs with different degrees of heat denaturation showed that the maximum load of both processed cheeses decreased and hardness of sensory evaluation was "soft", but the network structure differed for the two processed cheeses.

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Subcutaneous and intramuscular fats from Wagyu beef, crossbred cattle, dairy cattle beef and imported beef were heated and analyzed by dynamic-headspace solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). Aliphatic aldehydes and alcohols were higher in Wagyu beef than in other beef, while alkanes and aromatic compounds were higher in crossbred beef, and esters were higher in imported beef than in other beef. For lactones, which are presumed to contribute to the aroma of Wagyu beef,γ-C7, C8 and C9 in Wagyu beef fats and γ-C10, C12 and δ-C10 in dairy cattle beef and imported beef were significantly higher or tended to be higher than in other beef. The composition of lactones of crossbred cattle beef was closer to that of dairy cattle beef than that of Wagyu beef. In analysis of intramuscular fats, alkanes, aromatic compounds and esters were higher in fat of Wagyu beef, whereas the proportion of alcohols and aliphatic aldehydes was higher in fat from imported beef. The composition of volatile compounds differed between the subcutaneous fat and intramuscular fat even from the same kind of beef. For lactones, the amounts of γ-C4 and C6 in fat of Wagyu beef tended to be higher than in fat from other beef, although δ-C6, γ-C7, C8 and C9 tended to be lower than those of other beef. Composition of lactones of crossed cattle beef was closer to that of dairy cattle beef, as in the case of subcutaneous fats.

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A novel method for designing fluorescence fingerprint (FF) filters was proposed by applying the band-pass filter (BPF) design method, which is based on 2-dimensional reflectance spectra data, and expanding this method to 3-dimensional data analysis. This method consists of two steps : 1) the conversion of FF data into sensor output, and 2) selection of optimal BPFs. In the former step, BPFs with various light transmission properties are assumed to be put in front of the excitation light source and fluorescence detector. Then, the fluorescence intensities when measured with the above mentioned BPFs are calculated from the original FF data. In the selection of optimal filters, the best BPFs with the highest prediction or discrimination power are selected. “Yogurt multi-way fluorescence data”, in which FFs of yogurt samples had been measured under 225 different wavelength conditions, was used as a test data set for the proposed method. It was reported that partial least squares regression (PLSR) had been applied to the data set for the prediction of riboflavin content with root mean squared error of cross-validation (RMSECV) of 0.092 ppm. When the proposed method was applied to this data set with 3 or 4 variables, better prediction results were obtained with RMSECV of 0.081 or 0.074 ppm, indicating the potential of the proposed method for more accurate FF analysis with smaller number of wavelength conditions than conventional methods.

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Historically, taro was widely consumed in Japan; however, more recently, the consumption of taro has decreased rapidly. In this study, in an effort to expand the application of taro, the utilization of taro for beer fermentation was investigated. The addition of taro paste into wort increased the viscosity of the wort, which caused difficulty in the filtration process. Sensory evaluation of the resulting beer was poor due to its low nitrogen content, paleness and low alcoholic content. Thus, dried taro powder was used instead of taro paste. The powder was first roasted to add flavor and color through amino-carbonyl reaction. The addition of the roasted powder into wort did not increase wort viscosity; therefore, the workability increased. Hot water soluble polyphenols in taro powder increased as the roasting duration increased. Large scale brewing was performed using medium-roasted taro powder, which had color values of L* : 72.79, a* : 3.56, and b* : 19.35. All processes were completed without problems and the resulting beer was organoleptically evaluated fair as low malt beer. Generally, low malt beers contain little functional components; however, this low malt beer contained a certain amount of polyphenols and dietary fibers.

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Analysis of free amino acids, free sugars and sugar alcohols, organic acids and 5′-guanylic acid as well as a sensory evaluation were carried out to obtain basic nutritional data on the mushroom Pleurotus eryngii var. tuoliensis (Basidiomycetes). The free amino acid composition of freeze-dried samples in decreasing order was arginine, glutamic acid, aspartic acid, alanine and histidine. Functional amino acids ornithine, gamma-aminobutyric acid and citrulline were detected. The main free sugar and sugar alcohol was trehalose. The trehalose content was high and was found to be a characteristic taste component of the variety. Malic acid, fumaric acid and succinic acid comprised ≥80% of the organic acids. Investigation of changes in taste components following rehydration, which is a necessary step when using dried mushrooms in heated dishes, showed an increase in free amino acids following rehydration and almost no changes with subsequent heating. Conversely, 5′-guanylic acid increased with heating, and the increases tended to be greater for mushrooms soaked at lower temperatures. Hydrophobic amino acids produced in the rehydration process are hypothesized to be a factor affecting bitterness and palatability in sensory evaluations.

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A determination method of melatonin in boiled rice using precolumn derivatization was developed. The extraction method was as follows. Boiled rice (20 g), 10 g of distilled water and 0.1 g α-amylase were weighed into a mortar, the boiled rice was liquefied by homogenization at 40°C for 10 min, and stirred for 20 min on a magnetic stirrer. Then, 2.5 g of Na₂CO₃ was added to the mixture, the mixture was homogenized by a glass homogenizer, and stirred for 60 min at room temperature. The melatonin in the mixture was extracted with dichloromethane and adsorbed to Sep-Pak Silica cartridge. The adsorbed melatonin was eluted by dichloromethane/ methanol (1 : 1), and the eluant was evaporated to dryness. For the derivatization of melatonin, 150 μL of aqueous 2 mol/L Na₂CO₃, 100 μL of 100 mmol/L H₂O₂, 50 μL of 1 mmol/L CuSO₄ and 700 μL of water were added to the residue, and the mixture was heated in a water bath (94-96°C) for 6 min. The synthesized melatonin derivative was extracted with ethyl acetate, evaporated to dryness, dissolved in 15% (v/v) aqueous CH₃CN, and subjected to HPLC analysis. When standard melatonin was added to the liquefied boiled rice, the recovery rate was 99.6±6.9% (mean±S.D; n=6) for milled rice and 76.7±5.6% (n=4) for brown rice. Melatonin content in boiled rice was determined to be 71.6 and 86.2 pg/g for two cultivars of milled rice 107.0 and 130.2 pg/g for two cultivars of brown rice, and 36.2, 36.6 and 50.5 pg/g for three brands of commercial packaged boiled rice. These results suggest that the present method is suitable for the determination of melatonin in boiled rice.

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