The regional chemical compositions and microbial flora of commercially-produced hatahatazushi, fermented sushi from Akita Prefecture, have not yet been sufficiently examined. Moisture content, water activity, salt content, pH, organic acid content, free amino acid content, free saccharide content and microbial flora of hatahatazushi were investigated. The results indicate that two types of hatahatazushi are currently being produced. Products from the northern and southern coastal regions of Akita Prefecture were produced without lactic acid fermentation and classified as hayazushi. Products from the central coastal region produced with lactic acid fermentation were classified as namanarezushi, a more traditional form of hatahatazushi. Microbial growth in northern and southern coast products was inhibited by acetic acid during the manufacturing process, and was also by low water activity in southern coast products. This is the first study to scientifically demonstrate that two types of hatahatazushi are being produced in Akita Prefecture.

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We examined the effectiveness of superheated steam (SHS) for sterilizing buckwheat flour, for preserving raw buckwheat noodles and for processing preservable and savory buckwheat noodles. Commercial buckwheat flour has been found to contain more than 5log CFU/g of viable bacterial cells, which exceeds the number of cells found in wheat flour (2.6log CFU/g). Most bacteria were found on the pericarp and surface of the grains, and some were present inside the grains. Treatment with SHS was found to reduce populations of total bacteria and coliforms on buckwheat grains to less than 2log CFU/g viable cells. Viable cell counts of buckwheat flour milled from grain treated with SHS were also less than 2log CFU/g, and SHS treatment significantly improved the preservation of buckwheat noodles. Furthermore, SHS treatment did not affect the color tone of buckwheat flour or the sensory characteristics of buckwheat noodles. These results suggest that SHS treatment may be useful for processing buckwheat noodles that are superior in savor and preservation.

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Cyclic nigerosyl-(1→6)-nigerose (CNN) has a unique structure consisting of four glucose residues connected by alternate α-(1→3)- and α-(1→6)-linkages. We investigated the crystal properties of CNN and the stability of powdered functional oils using CNN. As a result of thermal analysis, we found that CNN takes 3 crystal forms, 5H₂O, 1H₂O and anhydrous crystals. The alcohol retention capacity of variously cyclic saccharides, such as α-, β- and γ-cyclodextrin (CD), was also examined. Ethanol and propanol retention capacities were observed in the order β-CD>CNN>β-CD>γ-CD. We then examined the stability of powdered fat-soluble vitamins, vitamin D₃, vitamin E and eicosapentaenoic acid, by using anhydrous CNN ; CNN-functional oil powders showed the highest residual values. These results indicate that CNN is useful for powdering easily oxidized fat-soluble substances.

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To study the palatability of chocolate, chocolates formulated from cacao beans from different countries were investigated by sensory evaluation and instrumental analysis. We conducted binary sensory evaluations with trained panels (n=20) for a descriptive analysis test and untrained student panels (n=50) for a preference test based on a seven-point scale using the Accra (Ghana) sample as a reference. For statistical analysis, ANOVA and Tukey tests were performed using SPSS (ver. 13.0j). In the descriptive analysis test, the Carenero (Venezuela) and Arriba (Ecuador) samples had high scores for floral notes, and weak scores for spiciness, smokiness, acidity, bitterness, and astringency. In the preference test, the untrained student panel preferred the Arriba and Carenero samples. In the instrumental analysis, there were significant correlations between pH and acidity (r=-0.69, p<0.05), pH and bitterness (r=-0.62, p<0.05), polyphenol content and acidity (r=0.89, p<0.01), polyphenol content and bitterness (r=0.87, p<0.01), and polyphenol content and astringency (r=0.77, p<0.05).

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A low-amylose rice cultivar (Awayuki-komachi) was cooked with various volumes of added water for about 12 minutes using an electric rice cooker. No pre-soaking process was used. The stickiness/hardness (S/H) ratio of the cooked rice was 0.31-0.34 with 150% hydration. A negative correlation between amylose content and water absorption in low-amylose rice (19 lines), glutinous rice (2 varieties) and non-glutinous rice (4 varieties) (r=-0.931) was observed. Cochineal pigment penetrated to the center of the Awayuki-komachi grains, suggesting that water moved from embryo to endosperm. The results suggest that Awayuki-komachi has potential for use as a “quick-cooking rice” if the cooking hydration is 150%.

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The effect of dried-bonito broth on the mental fatigue and stress caused by simple workload and task performance is investigated. After a 1-week non-ingestion period, female subjects (n=31, 20.5±0.6 years old) ingested dried-bonito broth (dry matter, 4.9g) daily for 1 week. The evaluation was performed after the non-ingestion and ingestion periods. For the simple workload, the Uchida-Kraepelin psychodiagnostic test (UKP) was administered. Profiles of Mood States (POMS) scores, flicker values and salivary cortisol were measured before and after UKP loading. After the non-ingestion period, post-loading flicker values were significantly lower than the pre-loading values, while there were no significant changes after the ingestion period. Pre-loading salivary cortisol concentrations significantly decreased during the ingestion period. Furthermore, UKP error rates after the ingestion period were significantly lower than after non-ingestion period. The results suggest that daily ingestion of dried-bonito broth for 1 week tends to lower the accumulation of mental fatigue and stress responses, and tends to suppress the lowering of task performance in a simple workload test.

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Changes in the quality of soybean oil heated using superheated steam (SHS) combined with far infrared heating (FIH) were compared to those of oil heated using SHS only. Oil quality was measured with respect to acid value (AV), peroxide value (POV) and viscosity. For the SHS treatment, oil was heated at two temperatures (180°C and 230°C). For the combined treatment of SHS with FIH (SHS + FIH), oil temperature was 180°C and the surface temperature of the FIH ceramic heater was 230°C.
Changes in oil heated by SHS+FIH were similar to those in the SHS-only treatment. All quality values of SHS+FIH oil were between those of the 180°C SHS-only treatment and the 230°C SHS-only treatment. The results indicate that FIH heating combined with SHS does not significantly affect oil quality compared to SHS-only heating, although the treatment temperatures of both methods influenced oil quality.

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We developed a simple and effective method for measuring concentrations of α-carotene, β-carotene and lycopene in acetone extracts of common carrots and Kintoki red carrots. This method utilizes the differences in visible absorption spectra for each of these pigments. Concentrations of each pigment can be determined by measuring the absorbance at 443, 475, 492 and 505nm, i.e., A₄₄₃, A₄₇₅, A₄₉₂ and A₅₀₅, respectively, and performing calculations. The equations, with correlation coefficients between prediction and measurement (r), and the standard errors of prediction (SEP), are as follows : α-carotene (mg/L)=0.847A₄₄₃+3.218A₄₇₅-1.499A₄₉₂-3.519A₅₀₅-0.119 (r=0.965, SEP=0.231) ; β-carotene (mg/L)=-1.488A₄₄₃+4.844A₄₉₂-2.352A₅₀₅+0.098 (r=0.946, SEP=0.228) ; lycopene (mg/L)=0.256A₄₄₃-1.984A₄₉₂+5.088A₅₀₅-0.237 (r=0.996, SEP=0.139). A standard spectrophotometer is sufficient for this method, and concentration calculations can be made within minutes of taking the absorbance measurements.

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