naringin

Scope: A literature synthesis on naringin moving from the membranes and albedo into the juice in grapefruit

Note: A secondary account drawn from the introductions of existing studies. Not a fixed content value for the white pith.

Scope: Direct measurement of natsumikan first-press juice (Nihon Kankitsu Kogyo K.K., Yawatahama factory, batch produced in mid-March)

Note: A 1962 analysis. Note that the content differs by more than twofold between pressing stages (1st vs. 2nd press).

Scope: Kumamoto Prefectural Industrial Technology Center research, 2005-2007 fiscal years, 8-variety comparison

Scope: Kumamoto Prefectural Industrial Technology Center research, 2005-2007 fiscal years, 8-variety comparison

Scope: Kumamoto Prefectural Industrial Technology Center research, 2005-2007 fiscal years, 8-variety comparison

Scope: Wakayama Prefecture product introduction webpage.

Note: The prefectural material states 『八朔に特徴的な苦味は、ナリンギンというポリフェノールの一種の成分によるもの』 (in translation: Hassaku's characteristic bitterness is due to the component naringin, a type of polyphenol) and that naringin is abundant in the joumou (inner membrane). Sections regarding claimed benefits (antioxidant, obesity prevention, hypertension prevention) are excluded as outside NIGAMI LAB's scope. As an administrative product introduction article without presentation of measured data, it is treated as contextual per the drug plant evaluation report protocols.

Scope: Part-by-part analysis of 1 sample of natsumikan (from Yugawara). The fruit was quartered and divided into peel and fruit; of the peel, the outer 1/3 was taken as flavedo and the remaining 2/3 as albedo. Separated by thin-layer chromatography and quantified by fluorescence.

Note: This is the distribution of the amount of naringin, regarded as a bitter substance, not a sensory evaluation of bitterness (the main text treats naringin as one of the bitter substances and states that removing it is important in making marmalade). The part-by-part values are 1 point each, and the number of fruits and replicates are not described in the main text. Another study of the same natsumikan (Bessho et al. 1964) gave about 1300 mg% for albedo and segment membrane and about 360 mg% for the outer skin (flavedo) by a colorimetric method; the order is the same but the numbers differ.

Scope: Fruit of hassaku and Kawano natsudaidai harvested and stored at the New Variety Development Center of the Ehime Prefecture fruit and vegetable federation (from October 1981 to June 1982). 10 fruits were divided into peel (flavedo and albedo), segment membrane, core, seeds and flesh and analyzed.

Scope: Juice of hassaku, natsumikan and Kawano natsudaidai squeezed with a reamer-type test juicer, quantified by high-performance liquid chromatography. Harvested from December 28 to May 8.

Scope: Natsumikan juice squeezed with a reamer-type test juicer, quantified by high-performance liquid chromatography. Harvested from December 28 to May 8. The table labels the cultivar Natsudaidai, while the main text calls it natsumikan.

Scope: Fruit collected from February to March from 1 natsumikan tree at an orchard in Matsuyama, Ehime Prefecture. Each part was finely cut and ground with 5 times its volume of water, the filtrate after heating for 30 minutes in a boiling bath was quantified by Nakabayashi's modified Davis method (colorimetry at 420 nm).

Note: This is the distribution of the amount of naringin, regarded as a bitter substance, not a sensory evaluation of bitterness (the main text describes the bitterness of natsumikan as due mainly to naringin). Differences between fruits were large, with a range of 1.5 to 1.8 times in the juice. In fruit harvested on April 6, the albedo (869 mg%) and segment membrane (978 mg%) were lower, and the amount fell sharply outward from the albedo and segment membrane (a mean of 5 fruits; the author says it is not certain without increasing the number of samples). Fukutani and Miyamoto (1983) point out that the colorimetric method also picks up other flavonoids and so gives higher values than HPLC.

Scope: Fruit from 1 natsumikan tree at an orchard in Matsuyama, Ehime Prefecture. The juice sacs of the flesh, with the segment membrane removed, were divided into the stalk, central part and tip, and quantified by the modified Davis method. The juice was withdrawn with an injection needle.

Note: This is the distribution of the amount of naringin, not a sensory evaluation of bitterness. The author considers that bitterness could be removed almost completely by removing naringin from the stalks and membrane without moving it into the juice part, and conjectures that for peeled flesh, removal from the dorsal side would be more effective than from the ventral side (a conjecture, not confirmed by experiment). The concentration values are by a colorimetric method.

Scope: Naringin in the flesh (juice sacs), segment membrane and peel of Kawano natsudaidai was compared between the portion extracted with water after complete grinding and the total amount obtained by heating after grinding.

Note: This result differs from the earlier explanation (Nakabayashi's theory, cited by Tsusaka 1965) that 40 to 70% of the naringin in natsumikan is in an insoluble or bound form that becomes soluble on heating. Bessho et al. and Manabe et al. (1964, natsumikan) also reported that more than 90% of the amount found after heating dissolved out by grinding alone, with the insoluble or bound form being only a part.

Scope: The introduction of a production test of canned natsumikan in syrup (Nomura et al. 1963). No measured values underlying the proportion are shown in the main text.

Note: The "80% and 20%" is the author's rough estimate, and its source or measurement is not described in the main text. It is not a proportion based on sensory evaluation of bitterness. It is an estimate from 1963.

Scope: Flesh (juice sacs) of natsumikan from Hiroshima. It was divided into the outer, central and middle parts of the flesh and the juice-storing and stalk parts of the juice sacs, and the naringin dissolving out in a short soak in water and the total naringin were measured by the modified Davis method.

Note: This is the distribution of naringin amount, not a sensory evaluation of bitterness. In fresh fruit, about 1/3 of the total naringin in the juice-storing part and about 1/4 in the stalk part dissolved out in a short soak in water, and after freezing about 2/3 in the juice-storing part and about 1/3 in the stalk part dissolved out. The point that the stalks of natsumikan juice sacs hold a high concentration of naringin agrees with Bessho et al. (1964, about 1.4% in the stalk). The numbers were confirmed in Tables 7 to 9 and the main text. The amounts dissolved from the segment membrane (290 and 219 mg/100 g) are values from separate tests in Table 7 and Table 9, and are the amounts that dissolve when the membrane and flesh are soaked briefly in water, not content.

Scope: In many of the citrus products where it occurs, an immediate bitterness contribution

Note: How much is present and how much it matters differ by citrus species and product.

Scope: The value in water comes from a panel of 20-27 screened judges. The statement about juice derives from debittering literature citing the same lineage

Scope: Layer: Solution. Not actual grapefruit juice, but a model beverage composed with color, aroma, naringin concentration, and sucrose concentration as factors. Descriptive analysis by a trained panel of 16 raters and acceptance evaluation by a consumer panel of 90 raters (female, aged 18-24).

Note: This supports a household method of 「甘みで苦味を和らげる」 (in translation: alleviating bitterness with sweetness) beyond resin adsorption and naringinase, but the results are from a model system and reproducibility in actual beverages requires separate confirmation.

Scope: A panel of 10 laboratory researchers, repeated 2 times, ascending series of the method of limits (5 mL taken into the mouth in order from low concentration, and the concentration at which bitterness is perceived reported). Purified commercial naringin was used.

Note: These are values in a model solution. They are higher than the value in distilled water (Guadagni et al. 1973, already recorded on the site: 20 mg/L = 2 mg/100 g), but the main text states that bitterness is affected by sweetness and sourness. The main text notes that individual differences were large, with some people perceiving bitterness easily and others not. In the cumulative proportion table (Table 6), 8 mg/100 g is 50%, 10 is 60%, 12 is 70%, 15 is 80% and 20 is 100%.

Scope: Heterologous in vitro receptor assay cited in genetic research. Limonin similarly did not activate it, according to the report.

Scope: Layer: Grapefruit juice, naringinase immobilized on agarose carrier (octyl-glyoxyl agarose).

Note: Treatment with the carrier resulted in a 74% reduction in naringin concentration, according to the report.

Scope: Layer: Food. Kao Nampung pomelo mesocarp powder, beta-CD 0.0/0.3/0.5/0.7/0.9% (w/v) compared with and without ultrasonic treatment (n=3, one-way ANOVA, Tukey test).

Scope: Layer: Food. Grapefruit juice, OGA-immobilized naringinase used sequentially for 5 batches by washing and recovering the catalyst every 24 hours of reaction at the same catalyst-to-juice ratio.

Note: The authors note that initial concentrations in each batch varied by season and growth stage. Specific values are not indicated in the text but appear only in Figure 9 as a graph, so verbatim citation remains qualitative in scope.