It is common to judge the palatability of food on the basis of its appearance. However, few studies have examined the viewer's mental process while this opinion is formed. In this study, we conducted a survey, using the SD method, of subjects'; impressions of photographs of cakes to investigate how the feeling of palatability is processed. We hypothesized several basic models for the mental process based on the results of the survey, and tested each of these by structural equation modeling. The model that best fits the survey data is as follows. Impressions of both colors and structures are created when the subject views a photograph of food. Both of these have a causal relationship, and the overall impression of the photograph is a combination of these impressions. The viewer's individual taste preferences in sweets affect impressions of color but not of structure. The overall impression of the cake photograph and the viewer's individual preferences combine to yield a total assessment of the photograph, which is a determination of how delicious the cake looks.

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The antithrombosis effect of sesame seeds and flour cultured with various microorganisms was investigated by fluidity testing of human whole blood and inhibition of human platelet aggregation. Extracts in 50% ethanol of sesame seeds contained sesamin and sesamolin but no sesaminol, and extracts of defatted flour showed no activity in these tests. However, extracts of flour cultured with Aspergillus niger (NRIC 1222) as well as flour treated with two types of hydrolysis enzyme showed strong activity in both tests, while flours cultured with Asp. awamori, Asp. oryzae, and Bacillus natto showed weak or no effects. HPLC analysis of these specimens showed that sesame seed and flour contains considerable amounts of sesamin and sesamolin but no free sesaminol, while the products cultured with Asp. niger or treated with enzymes contains significant amounts of sesaminol derived from glucosides. It was also demonstrated in tests using pure samples of sesame lignans that sesaminol exhibited strong activity in both tests, while sesamin and sesamol showed only weak activity in the platelet aggregation test, indicating the necessity of the active phenol group and lignan structure in the development of antithrombosis activity. Citric acid, a by-product of incubation, appears to have a weak additional effect on sesaminol in high concentrations.

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Descriptive analysis of the palatability of chocolate with varying fat contents (30∼45%) and fat composition was conducted based on rheological properties, DSC results, and sensory evaluation. Evaluation of high-quality chocolate was conducted by two panels, one containing 50 students and the other containing 13 trainees. The method of evaluation was a 7-point scale with “agree” or “disagree” options, and there were 17 item profiles for every 5g of chocolate per person. Statistical analysis (principal component analysis and multiple regression analysis) was conducted using SPSS (Ver. 13.0j) and Statworks (Ver. 4.0). The results showed that chocolate with a greater fat content, which melted in the mouth to a greater extent, resulting in a richer flavor, was preferred by the student panel but not by the training panel. Principal component analysis and multiple regression analysis showed that the two panels evaluated the chocolate from different angles, with the student panel employing a simple evaluation structure while the training panel used a multidimensional approach. Therefore, the evaluation of satisfaction, preference and high quality was conducted by training panel. It was found that the panel preferred chocolate with a fat content of 35 to 40%.

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It has been noted that soft-dried “Migaki-Nishin” herring does not rot despite containing large numbers of bacteria. Microbiological and chemical changes during the industrial drying process were investigated. The number of bacteria increased during drying, reaching 1.3×10⁸cfu/g on the final day, which was four days from the start of drying. The enterobacteria count obtained after drying was 2.3×10⁷cfu/g. Thirty colonies on standard plate count agar medium at five different stages were identified on the basis of the nucleotide sequence of the 16S rRNA gene. Identification showed that before drying the majority of bacteria belonged to the genera Streptococcus, Acinetobacter and Dermabacter, but after drying, the majority were Staphylococcus (about 70%). Specific multiplex PCR assays were used to determine the species of Staphylococcus isolated; the predominant species was found to be S. saprophyticus. Next, the amounts of amino acids and acetic acid present were measured to clarify the effect of microbes such as Staphylococcus in drying. The individual amounts differed among samples, but a slight effect on the formation of these chemicals was observed. It is thought that Staphylococcus may contribute to the quality of soft-dried “Migaki-Nishin” by controlling microorganism growth and preventing rot.

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A simultaneous determination method using HPLC was carried out to determine the net content of anthocyanins (AN) in purple sweet potatoes (PS) and processed foods made from them. The optimum HPLC conditions, which allowed good separation of the peaks of eight major ANs (named YGM-1a, -1b, -2, -3, -4b, -5a, -5b and -6) in the storage root of PS cultivar Ayamurasaki, were set by employing formic acid as an acidified solvent. Under these conditions, analysis was conducted in 40 min, which is considerably shorter than the time taken in previous experiments. In HPLC analysis of standard pigment YGM-6, the calibration curve showed a good linear correlation between concentration and peak area in the concentration range 10^-6 -10^-3M, and the detection limit for analysis was less than 11 ng. Moreover, the introduction of a quantitative factor by comparison of a standard YGM-6 peak area with the experimental YGM peak areas simplified the simultaneous determination.
This method was applied to fresh PS, dried PS powder and processed PS-based beverages (a carbonated drink and a fermented vinegar). The total major AN content was 369.1mg/100g in raw PS (cv. Ayamurasaki), with YGM-4b present in the largest amount, and peonidin-based ANs making up 81% of total AN levels. The compositions of major ANs in the dried powder, carbonated drink and fermented vinegar were similar to that of raw PS, with the total contents at 196.9mg/100g, 118.7mg/100g and 15.3mg/100g, respectively.

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For effective utilization of EPA and DHA in fish oil by addition to surimi-based products, we investigated changes in the physical properties, water holding capacity and color of heat-treated surimi gels prepared from walleye pollack, threadfin bream, white croaker, and Japanese jack mackerel by emulsification with fish oil. The fish oil was emulsified under vigorous mixing conditions with the rotation speed increasing stepwise. Various amounts of fish oil (0-40%) were added to salt-ground surimi paste with a fixed protein-water ratio. The following results were obtained: (1) The breaking strength and breaking strain of the heat-treated gels became greater as the amount of fish oil increased, in spite of the decrease in protein concentration in the mixture of surimi and fish oil. (2) The water holding capacity of heat-induced gels from emulsified surimi also became greater as the amount of fish oil increased, and emulsified oil was not released from the gels even when pressed at 1MPa. (3) The Hunter whiteness of the heat-induced gels increased with addition of fish oil. These results were obtained in surimi gels from all four fish species. It is thought that the interaction of surimi protein and fish oil contributes to the improvement of the gel properties.

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Sweetpotato tops exhibited angiotensin I-converting enzyme (ACE) inhibitory activity, with different levels of activity in the constituent parts of the tops. Leaves showed the highest activity, while that of stems and petioles was much reduced. Since there appeared to be a relationship between ACE inhibitory activity and the total content of the caffeoylquinic acids in the constituent parts, the ACE inhibitory activity of each caffeoylquinic acid was analyzed. 3,4,5-tri-O-caffeoylquinic acid (3,4,5-triCQA) showed the strongest activity, followed by 3,4-di-O-caffeoylquinic acid (3,4-diCQA), and 4,5-di-O-caffeoylquinic acid (4,5-diCQA). Spontaneously hypertensive rats (SHR) which were orally administered sweetpotato tops exhibited dose-dependent suppression in blood pressure increases in comparison with the control group. These results suggest that sweetpotato tops have a hypotensive effect in SHR, which is at least in part due to the ACE inhibitory activity of caffeoylquinic acids.

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Mice which were tube-administered a single dose of Adzuki polyphenol (APP) showed significantly lower blood glucose levels than the control group after feeding with potato starch, saccharose or maltose. However, no significant differences between the experimental and control groups were observed when glucose was given to the mice. When approximately 40% of the single-dose amount of APP was administered to mice daily for two weeks before feeding them with saccharose, blood glucose levels were significantly lower in the experimental group than in the control group. In streptozotocin-induced diabetic mice (STZ-DM), blood glucose levels after saccharose ingestion were significantly lower in mice which were administered a single dose of APP than in control mice. Also, in vitro experiments showed that α-amylase and α-glucosidase activities were suppressed depending on the concentration of the APP dose, and that when the APP-E and APP-M subfractions of APP were added to enzyme solutions, APP-M suppressed the activity of α-amylase and α-glucosidase. These results indicate that the suppression effect of APP-M on blood-sugar levels may be attributed to the suppression of activity of glycolytic enzymes.

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Instead of the usual benzene-based method, 1-butanol was used as a solvent for measurement of the carbonyl value (CV) of fish oil and oils extracted with diethyl ether from processed foods. CVs measured by the butanol method showed a good correlation not only with those obtained by the conventional method, but also with peroxide values. Due to its good reproducibility, the butanol method should be useful for evaluation of oxidative deterioration in fish oil and oil-containing foods.

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[in Japanese]

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