The smell and odorous components of dried shiitake mushroom, Lentinula edodes III: substances that increase the odorous compound content

This study formed part of an effort to improve the quality of dried shiitake mushroom [Lentinula edodes (Berk.) Pegler], in accordance with consumer preferences, and deals with the search for substances that increase the odorous component content. From analysis of sulfur and sulfur-containing substances in the culture substrate, rice bran was found to be the main source of sulfur, and 75% of this was present as cysteine and methionine. The sulfur-containing substances were added to a sawdust medium containing only rice bran and sawdust as a substrate; shiitake mushrooms were cultivated in the medium, the fruiting bodies were dried, and the 1,2,4-trithiolane content in the fruiting bodies was measured as an indicator of the odorous compounds. Of the sulfur-containing substances, those that increased odorous compounds the most were cysteine and methionine. The efficiency of cysteine in this regard was higher than that of methionine. It was also noted that the amount of glutamic acid increased the odorous compounds in combination with cysteine and methionine. Furthermore, the addition of both amino acids and glutamic acid had no negative effect on the yield. These results showed that it is possible to produce dried shiitake mushrooms with a smell suitable for particular consumer preferences.     

The smell and odorous components of dried shiitake mushroom, Lentinula edodes II: sensory evaluation by ordinary people

This study is part of an effort to improve the quality of dried shiitake mushrooms [Lentinula edodes (Berk.) Pegler], in accordance with consumer preference, and deals with a preference survey using questionnaires combined with sensory evaluation. The smell was evaluated using powdered dried shiitake mushrooms. Age, original preference (OP), sex, sensory intensity (SI), hedonic preference (HP), and sample amount were set as parameters. About 70% of panelists liked dried shiitake mushrooms. There were significant correlations among age, OP, and SI. There was also a significant correlation between OP and HP, but no significant correlation between SI and HP. However, when the panelists were classified by OP, there was an optimal value between SI and HP for likers and neutralists. The calculated optimal concentration of dried shiitake mushrooms for likers and neutralists ranged widely. On the other hand, there was a significant negative correlation between SI and HP for dislikers, and their HP decreased according to the increase in the amount of the substance. The results showed that different concentrations of odorous components in dried shiitake mushrooms were needed to satisfy different consumer preferences.     

The smell and odorous components of dried shiitake mushroom, Lentinula edodes V: changes in lenthionine and lentinic acid contents during the drying process

This study on dried shiitake mushroom [Lentinula edodes (Berk.) Pegler] focuses on the behavior of the aromatic lenthionine compound and its precursor, lentinic acid, during the drying process. Only a small amount of lenthionine was present after the drying process, regardless of the drying temperature or time; however, the amount increased during the rehydration process using pH 8.0 buffer. The lenthionine content after incubation in the buffer was correlated with the lentinic acid content in the dried shiitake mushroom. The lentinic acid content increased signifi cantly during the drying process at 40°C up to 4 h. The results show that the characteristic smell of dried shiitake mushroom was weak after drying, and that rehydration in a mild alkaline solution was necessary to increase the smell. The lentinic acid content of dried shiitake could serve as an indicator of the smell produced by rehydration and would be useful in screening to select odor-rich strains. Moderate heating likely caused the increase in lentinic acid content, which might be related to a reaction to heat.     

The smell and odorous components of dried shiitake mushroom, <Emphasis Type="Italic">Lentinula edodes</Emphasis> I: relationship between sensory evaluations and amounts of odorous components

The smell of food is one of the most important factors in assessing its quality. Concerning the smell of dried shiitake mushrooms [Lentinula edodes (Berk.) Pegler], 1,2,3,5,6-pentathiepane, commonly known as lenthionine, has been reported as a key compound. However, other compounds have not been studied sufficiently in connection with smell. From the results of sensory intensity studies and sensory evaluations of dried shiitake mushrooms, a positive significant correlation at 1% risk was observed between sensory intensity and sulfur perception. This showed that the smell of dried shiitake mushrooms was characterized by a sulfurous smell. Also, comparing the sensory intensity with the amounts of volatile components showed positive significant correlations at 1% risk between sensory intensity and three compounds: 1,2,4-trithiolane, 1,2,4,6-tetrathiepane, and lenthionine. Furthermore, significant correlations at 5% risk were obtained between the amounts of these three compounds and sensory intensity by multiple regression analysis. This showed that the smell of dried shiitake mushrooms depended on these compounds. The partial regression coefficient of 1,2,4-trithiolane was larger than those of the others, and so it was proposed that 1,2,4-trithiolane could serve as an indicator to estimate the smell of dried shiitake mushroom.     

The smell and odorous components of dried shiitake mushroom, <Emphasis Type="Italic">Lentinula edodes</Emphasis> IV: survey of trends in consumer preferences and changes in sensory evaluation

This study is part of an effort to improve the quality of dried shiitake mushrooms (Lentinula edodes) in accordance with consumer preference. Results are presented of a trend survey that examined the preferences of consumers using questionnaires combined with sensory evaluation. From the original preference (OP) survey, the distributions of OP divided by age class (AC) were statistically equal to the results obtained in 2000. The medians of OP for teenagers and twenties were “neutral” and “slightly like,” respectively. A firm preference change occurred between teenagers and those in their twenties. It is empirically realized that sensory intensity (SI) scores that were too high or too low led to a low hedonic preference (HP) score. The same tendency was seen for “neutralists” and “likers.” In addition, almost all distributions concerned with HP had no significant difference between 2000 and 2005; for example, that of SI divided by AC. These results showed that the preference for dried shiitake mushroom has been unaffected by the passage of the past 5 years. Dried shiitake mushrooms have been used from ancient times and for many dishes; therefore, the overall preference appears to have remained unchanged.     

Effect of increased harvests on saccharification ratio of waste mushroom medium from the cultivation of shiitake mushroom (Lentinula edodes)

Waste mushroom medium (WM) was saccharized with cellulase to obtain glucose after shiitake fruiting bodies were harvested 3 and 5 times (WM-3 and WM-5, respectively). Glucose can be used as a feedstock for the production of bioethanol or other bioproducts. WM-3 and WM-5 were analyzed for the amounts of shiitake fruiting bodies harvested and chemical components. The fresh weight ratio of shiitake fruiting bodies from the 4th and 5th harvests relative to the total fresh weight of shiitake fruiting bodies until the 5th harvest was 4.1 %. The additional 2 harvests decreased WM dry weight to 78.0 % and slightly decreased acid-insoluble lignin and xylan contents from 11.9 and 12.0 % to 10.0 and 9.6 %, respectively. The additional 2 harvests did not decrease glucan content. WM-5 included 31.6 % of glucan relative to dry weight, and 54.5 % of the glucan was saccharized to glucose with Meicelase (5 FPU/g substrate) at 40 °C for 48 h without pretreatment. The saccharification ratio of WM-3 was 45.0 % under the same saccharification condition. The amounts of saccharized glucose in WM-3 and WM-5 were 155.1 ± 9.8 mg/g substrate and 191.3 ± 9.2 mg/g substrate, respectively.     

Effect of steam treatment for the enzymic saccharification of waste mushroom medium after cultivation of shiitake mushroom (Lentinula edodes) and enokitake mushroom (Flammulina velutipes)

Waste mushroom medium of shiitake and enokitake (WS and WE, respectively) was steamed (StmWS and StmWE, respectively) and saccharized with cellulase to obtain glucose which can be feedstock of bioethanol or other bioproducts. Mushroom medium before cultivation of shiitake and enokitake (MS and ME, respectively) was also steamed (StmMS and StmME, respectively) and saccharized to compare with WS and WE. WS was stored at 15 °C for 1 month (SS), and SS was steamed (StmSS) and saccharized. The amount of glucose from StmSS was more than that from StmWS. The cellulose contained in StmSS and StmWE was saccharified earlier than that in StmMS and StmME, respectively. When StmSS and StmWE-added Meicelase of 5 and 3 FPU/g substrate (9.7 and 5.8 mg Meicelase/g substrate), respectively, was saccharized for 120 h, the saccharification ratio (the amount of glucose saccharized from cellulose/theoretical amount of glucose from cellulose) of them exceeded 80 %. The amount of glucose obtained from StmSS and StmWE was 311.0 and 207.7 mg/g substrate under the condition. It was found that the cellulose contained in mushroom medium was saccharized with less amount of cellulase by the influence of cultivation of shiitake or enokitake, storage of shiitake, and steaming.     

Screening of heterozygous DNA markers in shiitake (Lentinula edodes) using de-dikaryotization via preparation of protoplasts and isolation of four meiotic monokaryons from one basidium

A suitable screening method for heterozygous DNA markers in shiitake,Lentinula edodes (Berk.) Pegler, is reported. Monokaryons were derived from a dikaryon by de-dikaryotization via protoplast formation. Compatibility of the monokaryons was determined by pairwise culture on agar plates. We selected the primers to amplify polymorphic fragments among the original strain (Hokken600H600) and two monokaryons (H600PP-39 and H600PP-67) showing compatibility. A total of 135 fragments were selected as specific random amplified polymorphic DNAs (RAPDs) resulting from 56 primers of the 147 primers tested. Furthermore, we tested whether the polymorphic fragments segregated into 22 among four strains isolated from a basidium. Most of the polymorphic fragments (about 97.8%) showed 22 segregation among the four strains. We concluded that the polymorphic fragments were heterozygous if they were detected in either of the monokaryons (H600PP-39 and H600PP-67) and segregated to 22 among four meiotic strains (H600B-1,-2, -3, and -4). A total of 132 heterozygous DNA markers were therefore selected from a dikaryon of shiitake (Hokken600H600).Part of this report was presented at the 8th Annual Meeting of Mushroom Science and Biotechnology and the 47th Annual Meeting of the Japan Wood Research Society, Kochi, 1997     

The effects of chemical components and particle size on the mechanical properties of binderless boards made from oak (<Emphasis Type="Italic">Quercus</Emphasis> spp.) logs degraded by shiitake fungi <Emphasis Type="Italic">(Lentinula edodes</Emphasis>)

Binderless boards are composite boards that rely on self-bonding mechanisms for inter-fibre bonding. Quercus acutissima and Quercus serrata logs degraded by Lentinula edodes (shiitake fungi) were used in this study to investigate whether physical and chemical changes induced by shiitake fungi can enhance board mechanical properties. Binderless boards were manufactured with 0.8 g/cm³ target density, 220 °C pressing temperature, 5 MPa pressure, and pressing duration of 10 min. Boards made from logs degraded for ≥?26 months were stronger than control boards and met modulus of rupture (MOR) and internal bonding (IB) requirements for fibreboards. Chemical composition and particle size distribution of the wood powder used to make the boards were determined to elucidate the drivers of board mechanical properties. The proportion of small particles (<?150 µm) showed a strong positive correlation with MOR for both species and hot water extractives showed a strong positive correlation with IB for Q. acutissima boards. Introduction of shiitake fungi pre-treatment to the production process may enhance the mechanical strength of binderless boards.     

Saproxylic beetle assemblages on low stumps,high stumps and logs: Implications for environmental effects of stump harvesting

The aim of this study was to evaluate how future harvesting of spruce low stumps as a renewable energy source, might influence the saproxylic (wood living) beetle fauna. Species richness, abundance and assemblages of saproxylic beetles were compared on low stumps, high stumps and logs of spruce on 10 clear-cuts in northern Sweden. The sampling was conducted with emergence traps and a total of 929 individuals and 120 species were collected. No significant differences in beetle abundance or species richness were detected between substrate types. However, there were clear differences in assemblage composition between all substrate types. Our results suggest that low stumps created at final felling support as many species and individuals per volume dead wood as other dead wood substrates and that they are therefore overlooked as substrates for wood living organisms. Consequently, harvesting of low stumps might have negative effects on the diversity of saproxylic beetles, as up to 80% of the dead wood remaining on clear-cuts is in the form of low stumps. Future studies should evaluate if compensatory measures can be performed to minimize negative impacts.     

The distribution of Phratora vulgatissima (Coleoptera: Chrysomelidae) on cultivated willows in Britain and Ireland

Insect samples were collected from the canopy of 24 willow short rotation coppice (SRC) sites on farmland in Britain and Ireland in 1995. The blue willow beetle Phratora (= Phyllodecta) vulgatissima (L.) (Coleoptera: Chrysomelidae), previously identified as the main defoliating pest of this crop, was recorded from 13 of these at varying levels of abundance. Data describing aspects of the environment at each site were also collected. These data were used to create potential explanatory variables for a regression analysis of beetle abundance. This analysis indicated that P. vulgatissima were most likely to occur and were more abundant at older willow sites on clay soils and at sites that bad certain free-living willow species growing nearby. Within sites, most willow clones sampled contained P. vulgatissima, although two, Salix burjatica‘Germany’ (‘Aquatica Gigantea’) and Salix mollissima‘Q83’ (Salix triandra × Salix viminalis), were avoided. Chrysomelid pest avoidance and clonal resistance could form part of an integrated pest management strategy for SRC crops.     

The identification of fracture in dried wood based on theoretical modelling and acoustic emission

Physical interpretation of the three characteristic groups of acoustic signals emitted during convective drying of wood is the main subject of this paper. The acoustic emission (AE) was to evidence the fracture intensity during drying of a birch wood sample of cylindrical shape. To explain the three characteristic groups of acoustic signals, and particularly the last one, a mechanistic model of drying was applied to analyse the drying induced stresses in the tested sample. One can conclude from this analysis that the third group of acoustic signals arises when the surface stop to shrink and the wet core (initially in compression) begins to dry. The shrinkage of the core causes compression of the boundary layer and tension of the core. Thus, the reverse of the stress signs in the cylinder cross-section takes place and this possibly involves the destruction of wood structure in the tensed core.     

Populations of aphids, whiteflies and associated predators and parasites on different vegetables cultivated in plastic greenhouses

During 1996 and 1997, populations of aphids and whiteflies and their parasites were studied in plastic greenhouses under a chemical control program and in those free of pesticides. In the greenhouses free of pesticides, the parasite A. colemani destroyed 14.7?% of the aphids. B. tabaci had no effect on the cucumbers during the spring cultivation. However, it attacked the autumn cultivation. The parasite E. mundus killed 30?% of these nymphs. The parasite A. colemani parasitized up to 10?% of aphids on tomato plants in greenhouses free of chemical pesticides. The parasite E. mundus killed 15.7?% of whitefly nymphs. In greenhouses under a chemical pesticides program, aphids and whiteflies were found on the plants at the end of the plantation season, after the pesticide spraying had stopped. Although the pest population was low, the parasite A. colemani parasitized 8?% of the aphid population. Whiteflies were not found on tomato plants in greenhouses under extensive pesticides use.     

Effect of dried Gliricidia sepium leaf supplement on feed intake, digestibility and nitrogen retention in sheep fed dried KW4 elephant grass (Pennisetum purpureum) ad libitum

A feeding experiment was conducted to study the effects of supplementation with dried Gliricidia sepium leaves on dry matter (DM) intake, digestibility and nitrogen retention in sheep fed KW4 elephant grass. Four mature rams were fed elephant grass ad libitum supplemented with four levels of gliricidia leaves (0, 4, 8 and 12 g DM kg⁻¹ lwt day⁻¹) in a 4 × 4 Latin square design. Supplementation with gliricidia leaves decreased elephant grass DM intake (g DM day⁻¹ or g DM kg⁻¹ BW^0.75 day⁻¹). However, the effect of supplementation on total DM intake of the rations was not significant (P >; 0.05). Total crude protein intake significantly (P < 0.001) increased with increasing levels of gliricidia supplementation. Total DM digestibility and body weight changes were significantly (P < 0.05) improved by gliricidia supplementation; with the highest digestibility coefficient (60.5%) and body weight gain (89.3 g/day) obtained at 8 g DM kg⁻¹ lwt day⁻¹. Gliricidia supplementation significantly (P < 0.001) improved nitrogen intake, absorbed nitrogen and retained nitrogen but with no significant difference at 8 and 12 g DM kg⁻¹ lwt day⁻¹ level of supplementation. The highest efficiency of N retention by sheep (44.9%) was obtained at 8 g DM kg⁻¹ lwt day⁻¹ level of gliricidia supplementation. The results indicated that supplemention of KW4 elephant grass with small quantities of gliricidia leaves up to 8 g DM kg⁻¹ lwt day⁻¹ enhance utilisation efficiency of the total ration. Further increases in the level of gliricidia supplementation, under the conditions of this experiment, reduced the intake of elephant grass leading to substitution effects of the basal. This revised version was published online in August 2006 with corrections to the Cover Date.     

Status of cypress aphid on Cupressus lusitanica and Juniperus procera in protected and cultivated forests of South Wollo,Ethiopia

In Ethiopia,Cupressus lusitanica and Juniperus procera are important tree species.The incidence of the cypress aphid,Cinara cupressi,which has not been reported before on the exotic Cupressus lusitanica is becoming catastrophic.The appearance of the insect was reported for the first time in 2003 in Ethiopia.However,information is scarce on the status of this species in northeast Amhara state.The objectives of this study were to assess the extent of damage,abundance and status of the cypress aphid on C.lusitanica and J.procera in the protected and cultivated forests of South Wollo,Ethiopia.Results reveal that tree compositions of the three study areas differed.The dominant tree species were C.lucitanica(15–80%),Olea europaea(5–90%)and J.procera(14–70%).The cypress aphid showed significantly higher levels of infestation on C.lusitanica(35–90%)than on J.procera(1–16%).Moreover,there was higher C.lusitanica mortality(40–93%).In contrast,there was low infestation(1–16%)on J.procera and no mortality.The results reveal that the cypress aphid causes enormous losses of C.lusitanica.Therefore,it is recommended that insect surveillance be strengthened and the introduction bioagents be considered and integrated with other insecticides to minimize the degree of C.lusitanica infestation and loss.     

Production and investment evaluation of oyster mushroom cultivation on the waste dendromass: a case study on aspen wood in Slovakia

This paper addresses the processes and investment evaluation of utilizing available dendromass in an easy and close-to-nature way under Central European conditions in Slovakia. Wood of the European aspen (Populus tremula L.) that has generally been considered of little economic value was efficiently used as a growth medium for the oyster mushroom (Pleurotus ostreatus (Jacq.) P. Kumm.). The production of the fruiting bodies of this mushroom were evaluated for 5 years under natural forest conditions. The evaluation focused solely on aspen wood, specifically, the most valuable part – the trunk. The investment assessment revealed the high economic value of the fruiting bodies of the oyster mushroom inoculated into aspen wood blocks for the period of five years. In particular, the results of the net present value (NPV?=?347.78 €/m³) as well as the profitability index (PI?=?1.63) and discounted payback period (DPP ≈ 2 years and 8 months) point to the high profitability of such a project under the given conditions. The results could be helpful and inspiring for forest and garden owners when deciding how to utilize low-value waste dendromass, low-quality aspen wood and other tree species in small-scale forest management.     

攀西干热河谷退耕还林模式及效益评估

针对攀西地区干热河谷的生态环境 ,提出了适合不同立地条件的退耕还林的造林技术模式。论述了经济林模式、生态林模式、用材林模式和林草混交立体模式的适用立地条件、造林树种配置 ,并通过经济分析方法对攀西地区 1 4种主要退耕还林模式进行了经济效益评价     

Spatial distribution pattern of attack of the oak borer,Platypus quercivorus (Murayama) (Coleoptera: Platypodidae), and scolytid ambrosia beetles (Coleoptera: Scolytidae) on fresh logs

The spatial distribution patterns of the attack on fresh logs ofPasania edulis was studied for the oak borer,Platypus quercivorus (Murayama), and two species of Scolytid ambrosia beetles,Xylosandrus crassiusculus (Motschulsky) andXyleborus attenuatus Blanford, in 1994 and 1995. On the logs where onlyP. quercivorus attacked, the entry holes were distributed uniformly when attack intensity was low. However, the distribution pattern became more aggregated with the increase in attack intensity. On logs where bothP. quercivorus and the two Scolytid species attacked, there was a negative association between the spatial distribution of the entry holes ofP. quercivorus and that of scolytids. Simultaneous attack of two scolytids also increased the degree of aggregation of the entry holes ofP. quercivorus. The entry holes of scolytids were distributed in groups irrespective of the attack intensity of scolytids andP. quercivorus. These results suggest an asymmetrical interspecific relationship betweenP. quercivorus and scolytids. Concentration of the entry holes ofP. quercivorus in a small area may cause a considerable decline in the reproductive success in the galleries constructed there.