Detection of shiikuwasha (Citrus depressa Hayata) juice adulterated with calamondin (Citrus madurensis Lour.) juice was investigated by the analyses of (1) phloretin dihydrochalcone glucoside, 3',5'-di-C-β-glucopyranosylphloretin (PD) detected by thin-layer chromatography and high-performance liquid chromatography (HPLC), (2) polymethoxylated flavones (PMFs), included nobiletin, tangeretin, and sinensetin, detected by HPLC, and (3) γ-terpinene peak percentage obtained by headspace solid-phase microextraction gas chromatography with cryofocusing. PD was detected in calamondin juice (25.5 mg/100 mL) but not in shiikuwasha juice. Shiikuwasha juice contained higher levels of nobiletin (48.8 mg/100 mL) than calamondin juice (2.4 mg/100 mL). Shiikuwasha juice was characterized by containing a higher percentage of γ-terpinene (12.3%) than calamondin juice (0.7%). A discrimination function obtained by a linear discriminant analysis with PMFs and a peak ratio of [nobiletin/tangeretin] and γ-terpinene detected the adulteration with accuracies of 91.7%. These three chemical markers were useful to detect shiikuwasha juice that is suspected of being adulterated with calamondin juice.

We developed a simple method for quantification of the peroxide value (PV) in colored lipids on the basis of the reaction between triphenylphosphine (TPP) and oxidized oil to afford triphenylphosphineoxide (TPPO). Diphenylphosphineoxide (DPPO) was employed as internal standard. The formed TPPO was analyzed by high-pressure liquid chromatography-UV spectroscopy with absorption at 260 nm. The conditions that gave the highest correlative calibration curve between the peak area on the chromatogram and peroxide value were identified: the optimum TPP-oxidized oil mix ratio, reaction temperature, and reaction time were found to be 2:1, 40°C, and 30 min, respectively. Linear calibration curves, passing through the origin, were obtained for PV versus TPPO and TPPO versus DPPO. The quantification limit for this method was 2.01 pmol hydroperoxyl group, which corresponds to a PV value of 0.2 meq/kg in a 10-mg oil sample. This method was used to measure the PV in colored fats and oils or lipids extracted from dark meat and processed food containing a coloring agent. Though the official method could not measure the PVs in the colored lipids, the method proposed here, which uses an inexpensive chemical reagent and machine, could. The developed method could play an important role for food quality control.

The composition of volatile components in 18 Citrus Archicitrus species, 17 Citrus Metacitrus species and two Fortunella species, according to the classification system established by Tanaka, was investigated using headspace gas chromatography-mass spectrometry. The composition of 48 volatile compounds in the juice of these species was determined, and principal component analysis was performed. Scores for the 1st and 2nd principal components are plotted as a scatter diagram. In Citrus Archicitrus, samples of Citrophorum, Cephacitrus and Aurantium formed individual groups, but others did not. In Citrus Metacitrus, samples of Acrumen were divided into two different groups. The composition of volatile components in citrus juice was consistent with each grouping of Tanaka's system, in particular, in the case of dividing the Citrus genus into the two subgenera Archicitrus and Metacitrus.

No abstract

Owing to a gradual increase in fat intake, there is an increasing trend in the incidence of lifestylerelated diseases in Japan. In the Recommended Dietary Allowance of Japan(the sixth edition) , a balance in saturated : monounsaturated : polyunsaturated fatty acids at ３：４：３and an n-６／n-３ratio below ４ are recommended. However, putting such a recommendation into practice is not easy, and thus a fully worked out plan is necessary. The adjustment of the fatty acid balance of commercial foods rich in fats may be one such approach. Since the fat content and fatty acid composition of dressings have become very diverse in recent years, it seems important to determine the characteristics of commercially available dressings. Twenty-one mayonnaises, twenty-five dressings and twenty-three semisolid dressings, which were purchased from １ ９ ９ ７ to １ ９ ９ ９, were analyzed. It is generally assumed that the dressings were of the linoleic acid type, although they were actually of the oleic acid type. An n-６／n-３ ratio below ４ was noted in ６ １％ of all the tested samples. Among the tested products that are made in Japan, ７ ２％ of the mayonnaises, ６ ０％ of the dressings, and ６ ８％ of the semisolid dressings showed an n-６／n-３ ratio below ４. These results indicate that most commercially available dressings in Japanhave a health-intended fatty acid composition with their n-６／n-３ ratio below ４ and that the use consumption of only dressings made in Japan is recommended for good health.