Soluble Tannins Research Articles

異なる地域での甘ガキ‘次郎’の自然脱渋過程の解析

When grown in colder northern districts of Japan, pollination constant/non-astringent (PCNA) persimmon fruits often remain astringent at harvest season.Fruit growth and changes in soluble tannin content in flesh of PCNA persimmon cv. Jiro were compared between fruits from Yamagata (colder, northern district) and from Kyoto (warmer, middle district) with reference to changes of mean temperature in both districts in 1983 and from 1985 to 1987.Loss of astringency occurred before early or middle of August in Kyoto. In Yamagata, however, it varied with years; in some years the fruit had an astringent taste even in late September. This is suggested to be mainly due to the difference in mean temperature between the two areas during the period after bloom, especially in late stage of fruit growth. In Yamagata, the high mean temperature accelerated fruit growth in early stage, resulting in faster decrease of soluble tannin content. Larger fruit contained less soluble tannin than smaller fruit harvested on the same day at the same place. In the colder area, a little astringent taste is sometimes retained in the fruit at the later stage, after August. No clear relationship was observed between complete disappearance of the astringency and the mean temperature in the later stage.In Kyoto, fruit growth and soluble tannin content were investigated on several PCNA cultivars. There was no clear relationship between fruit growth and soluble tannin content. Cultivars retaining astringent taste at the late stage tend to contain more tannin substances at the immature stage. The rate of removal of soluble tannin, however, was not different among the cultivars.

カキ‘平核無’果実の脱渋性に及ぼす熟度の影響

The effect of harvest maturity on removal of astringency in Japanese persimmon, ‘Hiratanenashi’ fruits was examined.Individual fruits were put in a plastic chamber with different concentrations of ethanol solution as the reagent for removal of astringency at 20°C.The more immature the fruits and the higher the concentration of the reagent for removal of astringency, the faster the decrease in soluble tannin content and the decline in flesh firmness during the treatment.Ethanol which was taken into the fruits during the treatment was greater as the concentration of the reagent increased, and there was almost no effect of harvest maturity on the amount of ethanol in flesh. Acetaldehyde content in flesh was, however, greater in younger fruits than in mature ones.These results suggest that the fact that removal of astringency occurred more easily in younger fruits than in more mature ones may be mainly due to more active conversion of ethanol, which was taken into the fruits during the treatment, to acetaldehyde in flesh.

Maturation and chilling sensitivity of ‘Fuyu’ persimmon fruit in New Zealand

Abstract Seasonal changes in fruit growth, soluble tannins, soluble solids concentration, colour, fruit firmness, and chilling sensitivity were recorded during fruit maturation of the persimmon cultivar, Fuyu. Comparisons were made between fruit growing in Auckland and Gisborne in two seasons. There were major variations between seasons in soluble solids concentrations, soluble tannins, and colour as fruit matured. Chilling sensitivity was also greater in one year than another. Tannin content and chilling sensitivity of fruit varied between sites within a season. These results confirm observations that maturation of persimmon fruit in New Zealand does not follow the same pattern as it does in Japan.

カキ′伝九郎′果実と′平核無′果実の脱渋性の比較

The characteristics of removal of astringency of two Japanese persimmon (Diospyros Kaki Thunb.) cultivars, ′Denkuro′ and ′Hiratanenashi′, when treated with warm water, ethanol vapor and CO2 gas, were investigated.The patterns of the changes in peel color and flesh firmness were much the same for each treatment in both cultivars.The astringency of ′Denkuro′ and ′Hiratanenashi′ fruits was removed with both warm water and CO2 treatments. Decrease of soluble tannin occurred earlier in ′Denkuro′ than in ′Hiratanenashi′ in warm water treatment. In the ethanol treatment, astringency of ′Hiratanenashi′ was removed gradually and thoroughly, whereas there was almost no decrease of soluble tannin in ′Denkuro′ for 6 days.Ethanol and acetaldehyde accumulated in the flesh earlier and their levels were a little higher in ′Denkuro′ than in ′Hiratanenashi′ fruits when treated with warm water. The patterns of ethanol and acetaldehyde accumulation were almost the same in CO2 treatment in the two cultivars. In ethanol treatment, much more ethanol accumulated in ′Denkuro′ than in ′Hiratanenashi′ fruits, but only little acetaldehyde was detected in ′Denkuro′, while a small but obvious amount accumulated in ′Hiratanenashi′. The decrease of soluble tannin was, on the whole, closely related to the level of acetaldehyde accumulation in both cultivars.The responses of fresh juice to acetaldehyde vapor seemed almost the same between the two cultivars.From these results, the cultivar differences between ′Denkuro′ and ′Hiratanenashi′ and their regulative mechanisms in removing astringency were discussed.

Changes in the levels of bioactive components of cotton bracts accompanying senescence.

A series of bracts from Deltapine 41 variety cotton were harvested weekly from October 16 through November 25, 1982, and examined for changes in biologically active components accompanying senescence. Aqueous extracts of cotton bracts (CBE) were tested for their ability to cause 5-hydroxytryptamine (5-HT) release from human platelets and contraction of isolated canine tracheal smooth muscle (TSM). In addition, the amounts of soluble tannins (the platelet-activating factor found in CBE) and endotoxin were determined for each CBE. The amount of CBE decreased significantly from October 16 through November 25, whereas endotoxin levels rose dramatically from October 23 to November 6 and declined thereafter. The amount of soluble tannin and platelet 5-HT release both decreased from highs on October 23 to unmeasurable levels on November 25. Smooth muscle contraction was attributed to two primary factors contained in CBE. The major constrictor was a 5-HT receptor agonist and its levels remained stable from October 16 through October 30, but then decreased to unmeasurable levels by November 13. In contrast, CBE also contained lesser amounts of an acetylcholine receptor agonist whose levels paralleled the changes in endotoxin levels. We conclude that several important biochemical changes occur in cotton bracts during senescence and that these changes profoundly influence their biological activity in various assays.

Changes in Tannin Cell Morphology with Growth and Development of Japanese Persimmon Fruit

Abstract Morphological changes in tannin cells were observed in ‘Fuyu’ [pollination-constant and nonastringent (PCNA)] and ‘Hiratanenashi’ [pollination-variant and astringent (PVA)], two of the four types of Japanese persimmon fruit (Diospyros kaki L.). Pores in the tannin cell walls of ‘Fuyu’ started to occlude on 24 July when cell enlargement had ceased. This occlusion coincided with cessation of tannin accumulation, as determined by soluble tannin content and fresh weight of fruit. The pores were almost completely occluded on 7 Aug. Pore occlusion preceded the coagulation of tannins. In ‘Hiratanenashi’, pores in the tannin cell walls expanded until 7 Aug. When enlargement of tannin cells ceased on 14 Aug., occlusion of the pores in the cell walls was initiated. This event also nearly coincided with cessation of tannin accumulation. The process of occlusion was much slower than in ‘Fuyu’ and was about complete on 16 Oct. Thus, the pores in the tannin cell walls appear to be involved in tannin accumulation.

Insect‐induced chemical changes in young lodgepole pine (Pinus contorta): the effect of previous defoliation on oviposition, growth and survival of the pine beauty moth, Panolis flammea

ABSTRACT. 1. Significantly more eggs were laid by adult female pine beauty moths (Panolis flammea (D&S)) on previously undefoliated lodgepole pine (Pinus contorta Douglas) saplings than on those which had been partially defoliated the year before.2. The larval weights, mean relative growth rates and survival rates of P.flammea were lower on defoliated trees than on undefoliated trees.3. Marked and significant differences between the monoterpene profiles of the shoot cortical oleoresin of defoliated and undefoliated trees were linked to oviposition preferences in P.flammea.4. Differences occurred between the levels of soluble tannins in previously defoliated and undefoliated trees.5. The results are discussed in relation to earlier work on insect‐induced changes in plants, and the significance of inter‐provenance differences in lodgepole pine response is assessed.

The effect of shoot growth stage of Pinus contorta and Pinus sylvestris on the growth and survival of Panolis flammea larvae.

Young Panolis flammea (Lepidoptera: Noctuidae) larvae were unable to survive on the mature (one-year old) needles of Pinus contorta and Pinus sylvestris. Larval growth and survival on the current year's shoots of the 2 pine host plants first incresed, and then decreased as pine shoot development progressed, the effect on survival being more marked at 10° C that 18° C. The survival of larvae on lodgepole pine on field-grown plants transferred to 10° C rose from 26% in March to 87% in mid May, and rose from 3% to 82% on Scots pine in the same period. Larval survival exceeded 70% for about 8 weeks on lodgepole pine and about 6 weeks on Scots pine, this period starting and ending earlier on lodgepole than on Scots pine. The nitrogen, water and phosphorus contents of both pines were at a maximum in May and decline gradually thereafter; the soluble tannin content showed a more complex pattern. These results are discussed in relation to the possible importance of phenological coincidence on the population dynamics of P. flammea with emphasis on its greater abundance on lodgepole pine in Scotland.

Decomposition of boreal forest litters from central Alberta under laboratory conditions

Decomposition of foliage litter from jack pine (Pinusbanksiana Lamb.), white spruce (Piceaglauca (Moench) Voss), balsam fir (Abiesbalsamea (L.) Mill.), green alder (Alnuscrispa (Ait.) Pursh.), two feathermosses (Hylocomiumsplendens (Hedw.) B.S.G., Pleuroziumschreberi (Brid.) Mitt.), and a lichen (Cladinamitis (Sandst.) Hale & W. Culb.) was examined by measuring weight loss at 5-week intervals during a 35-week laboratory incubation (constant moisture, 23 °C). Weight loss by most litter types was more precisely described by a two-component than a one-component exponential decay model. Decomposition of lichen was best described by a one-component model as is consistent with the chemical and structural homogeneity of this litter. Decay rate was not correlated with concentration of C, N, soluble tannin or lignin, C:N ratio, or lignin:N ratio, although weight loss and lignin:N ratio were correlated in a combined data set that included data from published literature. Cutting pine needles into 1-cm lengths doubled initial decomposition rates, indicating that physical constraints associated with litter structure exert a strong influence on decomposition. Such structural controls limit the use of litter chemistry to predict decomposition rates. Relative differences in decomposition rates among litter types appeared to be reflected in forest floor properties, suggesting that plant species play different roles in the control of decomposition-related ecosystem processes.

Inter-estuary variation and intertidal zonation of free-living nematode communities in tropical mangrove systems

Variation in population densities and community structure of free-living marine nematodes within 5 tropical mangrove systems in northeastern Australia were examined. Nematode densities In surface (0 to 5 cm) mangrove sediments were generally low (F = 150 ind 10cm-~) and ranged from 3 to 987 ind 1 0 c m ~ Highest densities (c = 1266 ind 10cm-~) occurred in winter in a seagrass flat near the Lockhart River estuary. Densities were not significantly different among estuaries, but dlffered seasonally (summer > winter) and with intertidal position (low > mid > high). Species diversity (H') was low to moderate (F = 2.43; range: 2.02 to 2.91) and number of species per site was low (F = 23; range: 11 to 53 species). Numerical classification, detrended correspondence analysis and nodal analysis suggested that nematode fauna1 groups differed in specles composition among intertidal zones and estuaries. Of the 205 species identified, only 3 were found in all 5 estuaries: the deposit feeders Terschellingia longicaudata and Anoplostoma viviparum, and the predator Trissonchulus oceanus. Combining all stations, deposit feeders were the dominant trophic group (c = 50 %) with nearly equal relative abundances of epistrate-feeders (c = 28 %) and omnivore/predators (2 = 22 90). Population densities and species diversity of nematodes in these tropical estuaries are low compared to nematode assemblages in other littoral habitats suggesting that nematode communities in tropical Australian mangroves are subjected to greater stress (e.g. soluble tannins, monsoonal rains) than their counterparts in other intertidal habitats.

The Ecology of Lobarion Pulmonariae and Parmelion Caperatae in Quercus Dominated Forests in South-West Norway

Abstract119 investigated Quercus trunks and 67 species of lichens, 23 bryophytes and 3 non-lichenized fungi are arranged by means of the Minimum Spanning Tree analysis, resulting in four Lobarion communities and one Parmelion community. Lobarion is restricted to bark with pH > 5.0 in old forests. pH and Ca-content in the bark are strongly correlated; Ca seems to originate from Ca-uptake through the roots of the phorophyte. Within a single site the soil also seems to be responsible for the variation in the Mg-content of the bark, being correlated with Ca. The dominating source of the regionalvariationinMg, however, seems to be marine aerosols. Parmelion caperatae occurs on acid bark of young trees. The bark is, however, rich in Mg. Soluble tannins in the bark decrease with increasing age of the phorophyte, but are probably of minor significance for the epiphytic vegetation.

カキ果実のタンニン細胞の発育過程と自然脱渋との関連について

This study was carried out to elucidate the mechanism of natural removal of astringency in pollination constant non-astringent (PCNA) type fruits of Japanese persimmon, especially focusing on development of the tannin cells.1. Development of the tannin cells in plastic-embedded flesh sections was observed using an image analysis system. The tannin cells in PCNA type fruits stopped their enlargement at the end of June, whereas those in pollination variant nonastringent (PVNA) and astringent (PVA), and pollination constant astringent (PCA) type fruits continued to increase in size until the end of July. Thus, final size of tannin cells was much smaller in the former fruits than the latter. Number of tannin cells per unit area was little variable in all 4 type fruits at any stage, so that in PCNA cultivars the area occupied by tannin cells reduced with time after tannin cells stopped their development. Such a decreasing process was coincident with the decreasing process of soluble tannins in PCNA type fruits.2. In PCNA and PVNA cultivars, the tannin cells of fresh pericarp sections stained with ferric chloride were observed in order to clarify whether or not tannins coagulated in early August. At this time soluble tannins in non-astringent type fruits were negligibly low in contents. The observation revealed that tannins in PCNA type fruits hardly coagulated by this time, although those in PVNA type fruits completely changed into insoluble complexes.3. These results suggested that the decrease of astringency of PCNA type fruits on trees might be mainly attributable to the reduction in relative area occupied by tannin cells, but not their coagulation. Such a reduction in area occupied by tannin cells started when development of tannin cells stopped, as mentioned above.

BROWNING OF LENTIL SEEDS, CONCOMITANT LOSS OF VIABILITY, AND THE POSSIBLE ROLE OF SOLUBLE TANNINS IN BOTH PHENOMENA

Under normal storage conditions, lentil seeds, Lens culinaris Medic. (Fabaceae), were observed to discolor gradually over a 2-yr period from the olive green of freshly harvested seeds to a light yellow and finally a deep brown. Browning was experimentally accelerated by exposure to a warm, humid environment and conversely, retarded by exposure to a cold or dry atmosphere. Browned seeds were judged less viable than green seeds on the basis of (1) a fainter reaction to the tetrazolium test, (2) lower percent germination, and (3) a higher electrical conductivity of the imbibition medium indicative of a loss of membrane integrity and resultant loss of cell solutes. Coats of both green and browned seeds contained a high amount of proanthocyanidins (condensed tannins), both procyanidin and prodelphinidin, but browned seeds exuded much lower amounts of low molecular weight proanthocyanidins (soluble tannins) into the imbibition medium than did green seeds. It is concluded that (1) browning was a result of polymerization of soluble tannins to brown-colored high MW polymers (condensed tannins), and (2) under experimentally provided storage conditions of high relative humidity, embryo death was hastened in the presence of the seed coat, possibly by the interaction of soluble tannins or their precursors with embryo membranes.Key words: Lentils, Lens, seed browning, seed ageing, proanthocyanidins, soluble tannins

The treatment of rapeseed meal and its effect on chemical composition and egg tainting potential

AbstractTreatment of high glucosinolate Brassica napus meals with lime, ammonia or by micronisation lowered their tainting potential by reducing their progoitrin, soluble tannin and sinapine contents. These effects were not sufficient to prevent inhibition of trimethylamine oxidation and the consequent rise in egg trimethylamine levels above the tainting threshold when the meals were fed to susceptible hens as sources of protein (100 g kg−1 diets).

Rapeseed meal and egg taint: Effects of low glucosinolate Brassica napus meal, dehulled meal and hulls, and of neomycin

AbstractWhole meals prepared from four cultivars (Tower, ‘French’ (unknown cultivar from France), Duo and Tandem) contained sufficient progoitrin and soluble tannins to impair trimethylamine (TMA) oxidation, and thereby allow the TMA content of eggs to rise above the tainting threshold, when they were fed as protein supplements (100 g kg−1) to hens which had been bred for low TMA oxidase activity. Hulls from Tower and ‘French’ seed produced small, but detectable, effects and since the potencies of dehulled and whole meals were similar, it was established that the hulls make only a very minor contribution to the tainting potential. Although the addition of neomycin to the drinking water when the Tandem whole meal was fed appeared to diminish its effects to a certain extent, it had little value as a prophylactic measure. It was concluded that these meals could produce widespread tainting if used commercially in the UK, and that the removal from the laying hens of the genetic defect which restricts the synthesis of TMA oxidase and thereby confers susceptibility is the only effective way of eliminating the problem.

Wound-induced changes in the palatability of Betula pubescens and B. pendula

Leaves of Betula were damaged artificially in April, June and August 1982. Palatability of damaged and adjacent undamaged leaves was assessed against controls in bioassays using the polyphagous Lepidoptera Spodoptera littoralis and Orgyia antiqua. Assessments were carried out at intervals from six hours to five months following each damage date. Palatability (relative proportions of leaves consumed) was significantly lower than controls in damaged and adjacent leaves after six hours and remained detectable for up to two months but this was less clear in the June-damaged samples and undetectable in the August group. Adjacent leaves were significantly affected whether distal or proximal to the damaged leaves. Marked and significant changes occurred in levels of soluble tannins in the damaged and adjacent leaves but the relationship between crude tannin levels and changed palatability was not simple cause and effect. No significant effects of damage on aphid (Euceraphis punctipennis) reproduction could be detected among birches in a growth room experiment in which half the trees were artificially damaged and half were controls. The results are discussed in the light of earlier work on induced defence in birch and five areas of significant new information represented by the results in this paper are identified.

Trimethylamine and Fishy Taint in Eggs

SummaryA “fishy” or “crabby” taint due to trimethylamine (TMA) occurs when the hen's capacity for metabolizing this substance is impaired and overloaded. Recently the causative factors were identified and their roles were determined.A strongly inherited genetic factor present in white and brown-egg breeds restricts the synthesis of TMA oxidase which is mainly responsible for the metabolism of TMA. This enzyme is inhibited by goitrin and soluble tannins supplied by both low and high glucosinolate rapeseed meals.TMA is released by the action of enteric bacteria on choline and TMA oxide. Both are present in fish meal and the former occurs in rapeseed meal in the form of sinapine. TMA derived from the choline in other commonly used dietary ingredients is sufficient to produce the taint when the inherent oxidation capacity of the hens is very low. The elimination of this defect by selective breeding is feasible and would provide the most effective solution to the problem.

Use of refractometer to determine soluble solids of astringent fruits of Japanese persimmon (Diospyros kakiL.)

SummaryA method was developed to determine soluble solids refractometrically in astringent Japanese persimmon fruits with a high soluble tannin content. Adding 5% PEG # 6000 to the fruit juice in equal amount followed by centrifugation or filtration removed interfering tannins effectively from the mixture by forming precipitates. The refractometer readings were taken with the resultant solution and 2.5% PEG # 6000 and then the refractometer sugar value of the original juice was calculated by multiplying by two the difference of the two readings. The calculated value approximated closely to the total sugar content of juice.

カキ果実の乾燥に関する研究

Astringent persimmons (Yokono cv.) were peeled and then sun-dried under usual weather conditions. The mechanism of astringency removal was examined, with particular attention given to the relation between gas exchange and the insolubility of soluble tannin in fruit. The amount of soluble tannin in persimmons decreased markedly during seven to nine day′s drying and the organoleptic test for astringency was almost negative. The fruit weight decreased about 45% during this period.1. The amounts of oxygen intake and carbon dioxide production from dried persimmons decreased markedly from the third to ninth days, after which the decrease was more gradual. On the other hand, in astringent persimmons dried with peels, in which astringency did not disappear, the amount of the above gases remained nearly constant through nineteen days of drying.2. Alcohols (containing both of methanol and ethanol) increased in percentage by weight as the persimmon dried, but the percentage remained almost constant when calculated relative to the original fresh fruit weight. The alcohol content was considerably greater than that of aldehyde from the beginning of the drying period. It is concluded that these alcohols do not affect the removal of astringency.3. Acetaldehyde was small in quantity in the fresh fruit, but during the first four weeks of drying it increased considerably to a value equal to that of the original fresh fruit weight.4. From these results, it can be concluded that the removal of persimmon astringency by sun drying is due to the reaction between soluble tannin and acetaldehyde which is formed by incomplete respiration due to the membrane formed on the fruit surface during drying and to the degradation of fruit tissues.

カキ果実の脱渋性に関する研究

This paper is a continuation of our preceding report and describes the effects of ethanol treatment for removal of astringency from the “on-tree” fruit of the Japanese persimmon, cv. Hiratanenashi, from the pre-bloom stage extending to the end of July on the reappearance of astringency and on changes in other fruit character-istics.Fruit or fruit buds at pre-bloom were enclosed in polyethylene bags containing 5 or 10ml of 5% ethanol until they completely lost their astringency. Then the bags were removed and the fruit was allowed to remain on the tree.1) Except for the fruit treated in mid- or late July, soluble tannin reappeared in the fruit within one to two weeks after de-bagging with increasing degrees of reappearance in earlier treatments. Fruit treated before mid- or late June displayed astringency throughout the flesh tissue, while those treated later did so only in portions of the flesh tissue near the calyx end.2) The browning of flesh tissue appeared strongly in the fruit treated at the end of June and later, except for the portion of flesh tissue near the calyx end where astringency reoccurred. In fruit in which astringency reoccurred in all the tissue, only minor and localized browning, if any, was detected at the distal end of the fruit.3) Fruit shape and size were variously affected by the dates of ethanol treatment. Treatments applied between mid-May and mid-June tended to cause flattening of the fruit. Those treated between late June and mid-July showed reduced fruit diameter and distorted shape, while treatment at the end of July had almost no effect on fruit shape and size.4) Mitotic activity of flesh tissue was most active from the end of May to early June, and almost ceased in late June and was located mainly in the calyx end of the fruit. Its possible contribution to the reappearance of astringency after ethanol treatment is discussed.