Safety assessment of the substance 'phosphorous acid, triphenyl ester, polymer with 1,4-cyclohexanedimethanol and polypropylene glycol, C10-16 alkyl esters', for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the substance 'phosphorous acid, triphenyl ester, polymer with 1,4-cyclohexanedimethanol and polypropylene glycol, C10-16 alkyl esters', when used as an additive in all types of polyolefins. The substance is a polymer containing ≤ 13% w/w of a low molecular weight fraction (LMWF, < 1000 Da). A polyethylene sample with 0.15% w/w of the substance was used in a comprehensive set of migration tests with food simulants. The specific migration was up to 0.014 and 0.023 mg/kg in 4% acetic acid and 10% ethanol, respectively. Migration into olive oil was estimated by the Panel to be up to 5.3 mg/kg under worst-case conditions of use. The migrating LMWF species were comprehensively identified. Those without phosphorous were either without alerts for genotoxicity or listed in Regulation (EU) 10/2011 with worst-case migrations well below their respective specific migration limits. Toxicological studies were performed using phosphite and phosphate versions of the substance enriched in its LMWF. The substance does not raise a concern for genotoxicity. From a repeated dose 90-day oral toxicity study in rats with a 50:50 phosphite:phosphate blend, the Panel identified a NOAEL of 250 mg/kg bw per day for each component of the blend. No delayed neurotoxicity in hens was observed. The CEP Panel concluded that the substance does not raise a safety concern for the consumer if its LMWF is not higher than 13% w/w, if it is used at up to 0.15% w/w in polyolefin materials and articles intended for contact with all food types, except for infant formula and human milk, for long-term storage at room temperature and below, after hot-fill and/or heating up to 100°C for up to 2 h, and if its migration does not exceed 5 mg/kg food.

A Novel O- and S-Methyltransferase from Pleurotus sapidus Is Involved in Flavor Formation.

Increasing consumer aversion to non-natural flavoring substances is prompting a heightened interest in enzymatic processes for flavor production. This includes methylation reactions, which are often performed by using hazardous chemicals. By correlation of aroma profile data and transcriptomic analysis, a novel O-methyltransferase (OMT) catalyzing a respective reaction within the formation of p-anisaldehyde was identified in the mushroom Pleurotus sapidus. Heterologous expression in E. coli followed by purification allowed for further characterization of the enzyme. Besides p-hydroxybenzaldehyde, the proposed precursor of p-anisaldehyde, the enzyme catalyzed the methylation of further hydroxylated aromatic compounds at the meta- and para-position. The Km values determined for p-hydroxybenzaldehyde and S-adenosyl-l-methionine were 80 and 107 µM, respectively. Surprisingly, the studied enzyme enabled the transmethylation of thiol-nucleophiles, as indicated by the formation of 2-methyl-3-(methylthio)furan from 2-methyl-3-furanthiol. Moreover, the enzyme was crystallized at a resolution of 2.0 Å, representing the first published crystal structure of a basidiomycetous OMT.

Fatty acids derived from oviposition systems guide female black soldier flies (Hermetia illucens) toward egg deposition sites.

The black soldier fly, Hermetia illucens, comes with big promises for industrial purposes since its larvae feed polyphagously on a broad spectrum of organic substrates. However, research focusing on adult flies is scarce, which is inconsistent with their reproductive relevance within the rearing cycle. In particular, directed oviposition is a challenge in artificial systems. Currently, decomposing organic matter is commonly used as oviposition substrate, which has extensive potential for improvement in view of the lack of standardization and the risk of microbial contamination. Here, we identified three fatty acids and one fatty acid methyl ester derived from the surface of old oviposition sites and targeted to elucidate their effect on preference behavior and oviposition site selection using Y-olfactometry and prepared oviposition sites, respectively. Exposure to tetradecanoic acid attracted gravid females and stimulated oviposition most strongly, while decanoic acid demonstrated a repulsive effect. Females kept in mixed-sex populations were attracted by tetradecanoic acid, resulting in a higher egg mass found in the compound box (3.0-11.4 fold), a ≥ 2.3 fold reduction of nonspecifically deposited eggs, and the highest total egg mass. Conversely, decanoic and dodecanoic acid caused females to lay a greater proportion of eggs nonspecifically outside both boxes. Our data suggest that fatty acids, especially tetradecanoic acid, are important cues for oviposition site selection in black soldier flies. In order to achieve a directed oviposition behavior, the role of further short- and long-chain fatty acids as attractants should be examined.

Safety assessment of the substance poly(2-hydroxypropanoic acid), n-octyl/n-decyl esters, for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of poly(2-hydroxypropanoic acid), n-octyl/n-decyl esters (OLA8), which is intended to be used as a plasticiser into polylactic acid (PLA) in contact with non-fatty foods. OLA8 is intended to be used at up to 5% and 15% w/w with or without starch, respectively (or with other additives with similar function). The migration for 10 days at 40°C from the film without starch was 0.16 mg/kg in 10% ethanol and 0.01 mg/kg in 3% acetic acid, while from the film with the starch it was well above 0.05 mg/kg food in all simulants. Some of the testing conditions were inconsistently reported. The substance did not induce gene mutations in bacterial cells and did not induce structural chromosomal aberrations or polyploidy in mammalian cells, thus, does not raise concern for genotoxicity. Instead of providing a 90-day oral toxicity study, a hydrolysis study in ■■■■■ was submitted to read-across from the authorised starting substances, ■■■■■ and the ■■■■■. However, the data provided did not allow to perform the read-across, thus no appropriate toxicological data were provided to support migration above 0.05 mg/kg food (including for contact with 10% ethanol and use in combination with starch). The Panel concluded that OLA8 does not raise a safety concern for the consumer if it is used as an additive at up to 15% w/w in the manufacture of PLA articles that do not contain starch (and other additives with similar function), that are intended to be in contact for 10 days at 40°C with foods simulated by 3% acetic acid and from which the migration does not exceed 0.05 mg/kg food.

Structure Elucidation of Aroma-Active Bicyclic Benzofuran Derivatives Formed by Cystostereum murrayi.

Among the monoterpenoid aroma compounds formed by the basidiomycete Cystostereum murrayi are highly potent bicyclic benzofuran derivatives. In addition to the dill ethers previously described in a few fungi, two stereoisomers of the rare 3,6-dimethyl-3a,4,5,6,7,7a-hexahydro-3H-1-benzofuran-2-one (1a and 2c), also known as dihydromenthofurolactones, and a C3-unsaturated analogue (3a) are formed by C. murrayi. The analysis of synthesized reference standards of the lactones allowed an unambiguous assignment of the stereoisomers formed by the fungus. Despite a similar structure, two key differences in the stereochemistry of the lactones and dill ethers emerged. The analysis of submerged cultures further revealed the formation of additional, so far unknown, fungal terpenoids, including limonen-10-ol (7) and the corresponding aldehyde limonen-10-al (8). Analysis of chiral terpenoids as well as supplementation studies, including stable isotope-labeled compounds, indicated independent biogenesis pathways for dill ethers and lactones.

Upcycling of black currant pomace for the production of a fermented beverage with Wolfiporia cocos.

Pomace as a side stream from black currant juice production is mostly discarded, even though it is rich in nutrients like protein, fiber, sugars, anthocyanins, polyphenols, and other secondary metabolites. Fungi from the division of Basidiomycota have a great enzymatic toolbox to recycle these complex mixtures of nutrients. In particular, the edible medicinal fungus Wolfiporia cocos has been described as a suitable biocatalyst to form pleasant aroma compounds in fermentation processes. Therefore, medium optimization, upscaling, and filtration were performed to produce a beverage based on black currant pomace fermented with W. cocos. A trained panel described the beverage as highly pleasant, reminiscent of honey, flowers and berries with a well-balanced sour and sweet taste. The flavor compounds linalool (citrus), geraniol (flowery), phenylacetic acid (honey), methyl phenylacetate (honey), eugenol (clove), and 2-phenylethanol (rose) were produced during fermentation and the concentrations exceeded their respective odor thresholds. The produced beverage was evaluated with 8.0 ± 1.4 from 10 for the question of whether panelists would buy the product. Fungal fermentation with the edible fungus W. cocos enabled the production of a highly pleasant beverage and additionally may reduce waste by using pomace and table sugar as sole ingredients. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05677-4.

Protein- and Carbohydrate-Rich Supplements in Feeding Adult Black Soldier Flies (Hermetia illucens) Affect Life History Traits and Egg Productivity.

The black soldier fly, Hermetia illucens (BSF; Diptera: Stratiomyidae), has come into the focus of research over the past decade since its larvae are polyphagous feeders with an exceptional substrate range, making them a promising candidate for the bioconversion of various organic side streams into valuable insect protein. While larval nutritional requirements have been studied in detail, basic information on adult feeding is still lacking. The reproduction of adult flies is a bottleneck and key determinant in rearing BSF, which has extensive potential for improvement. In the present study, we examined the impact of different carbohydrate (honey and d-glucose) and protein sources (Spirulina and Chlorella powder) on a variety of life history traits using a highly standardized single pair approach. Feeding a 5% honey solution was shown to make females live 2.8 d longer, become more fecund (9 egg clutches per 10 females), lay more eggs (increasing 1.7-fold to 182.4 mg per 10 females), reduce the number of failed oviposition events 3-fold and increase multiple oviposition events from 2 to 15. Additionally, female longevity after oviposition improved 1.7-fold from 6.7 to 11.5 d. In order to further optimize adult feeding, mixtures of proteins and carbohydrates with varying ratios should be tested.

Safety assessment of 'waxes, paraffinic, refined, derived from petroleum-based or synthetic hydrocarbon feedstock, low viscosity' for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP Panel) assessed the safety of the 'waxes, paraffinic, refined, derived from petroleum-based or synthetic hydrocarbon feedstock, low viscosity' (FCM No. 93), for which the uses were requested to be extended for articles in contact with fatty foods. Migration from low-density polyethylene samples containing 1% w/w of a representative wax was tested in food simulants. In fatty food simulants, the migration of mineral oil saturated hydrocarbons (MOSH) ≤ C35 was 142 mg/kg food, exceeding the overall migration limit for plastic FCM. Mineral oil aromatic hydrocarbons (MOAH) with at least two rings are largely removed during the manufacturing process. Based on various lines of evidence, the Panel concluded that any concern for the potential presence of MOAH with two or more conjugated aromatic rings can be ruled out. Based on the genotoxicity studies and on the content of polycyclic aromatic hydrocarbons (PAHs), the substance does not raise a concern for genotoxicity. Available toxicokinetic data showed a limited accumulation of MOSH. No adverse effects were observed up to the highest tested dose of 9 g/kg body weight per day in a 90-day repeated oral toxicity study in Sprague-Dawley rats. The available results showed that FCM No. 93 is devoid of endocrine activity. The provided information on chronic toxicity and carcinogenicity was limited and inadequate to reach conclusions on these endpoints. Therefore, the CEP Panel concluded that under the intended and tested conditions of uses, the substance does not raise safety concern for the consumer if used to a level ensuring that its migration into food is no more than 5 mg/kg.

Recombinant Thaumatin-Like Protein (rTLP) and Chitinase (rCHI) from Vitis vinifera as Models for Wine Haze Formation.

Cross-linking net aggregates of thermolabile thaumatin-like proteins (TLPs) and chitinases (CHIs) are the primary source of haze in white wines. Although bentonite fining is still routinely used in winemaking, alternative methods to selectively remove haze proteins without affecting wine organoleptic properties are needed. The availability of pure TLPs and CHIs would facilitate the research for the identification of such technological advances. Therefore, we proposed the usage of recombinant TLP (rTLP) and CHI (rCHI), expressed by Komagataella phaffii, as haze-protein models, since they showed similar characteristics (aggregation potential, melting point, functionality, glycosylation levels and bentonite adsorption) to the native-haze proteins from Vitis vinifera. Hence, rTLP and rCHI can be applied to study haze formation mechanisms on a molecular level and to explore alternative fining methods by screening proteolytic enzymes and ideal adsorptive resins.

Safety assessment of the process Loop Polymers, used to recycle polyethylene and polypropylene printed offcuts and scrap for use as food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Loop Polymers (EU register number RECYC252). The input consists of polyethylene (PE) and polypropylene (PP) offcuts and scrap from the production of food contact packaging that has not been in contact with food, but carry coatings, ink systems and adhesives. Decontaminated material is intended to be used to produce new articles for their original application. The Panel considered critical the management system put in place to provide full traceability from input to the final product, the material review before processing, as well as the removal of coatings, ink systems and adhesives during recycling. The CEP Panel considered that the applicant did not demonstrate that coatings, ink systems and adhesives were adequately removed during the process. Consequently, it concluded that the applicant has not demonstrated that the recycling process is able to reduce the contamination of the PE or PP recyclate to a concentration that does not pose a risk to human health.

Safety assessment of the process LOGIFRUIT, used to recycle high-density polyethylene and polypropylene crates for use as food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process LOGIFRUIT (EU register number RECYC260). The input consists of pre-washed high-density polyethylene (HDPE) or polypropylene (PP) crates from closed and controlled food distribution loops. The process separates crates by material type. Crates are ground to flakes, possibly extruded to pellets and used by companies approved to be in the loop to manufacture new crates. The Panel considered that the quality management system (QAS) put in place to ensure compliance of the origin of the input with Commission Regulation (EC) No 282/2008 and to provide full traceability is critical. The Panel concluded that, when run under the conditions described, the input of the process LOGIFRUIT exclusively originates from product loops which are in closed and controlled chains. The process is designed to ensure that only crates intended for food contact are used and that contamination other than by food can be ruled out. Therefore, the recycling process LOGIFRUIT to produce HDPE and PP crates to be used in contact with fruits and vegetables, and packed meat and fish, dairy, bakery and pastry products is not of safety concern.

Safety evaluation of the food enzyme chymosin from the genetically modified Kluyveromyces lactis strain CIN.

The food enzyme chymosin (EC 3.4.23.4) is produced with the genetically modified Kluyveromyces lactis strain CIN by DSM Food Specialties B.V. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its recombinant DNA. It is intended to be used in milk processing for cheese production and for the production of fermented milk products. Dietary exposure was estimated to be up to 0.73 mg total organic solids (TOS)/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,000 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, results in a margin of exposure of at least 1,300. Similarity of the amino acid sequence of the food enzyme to those of known allergens was searched for and four matches were found. The Panel considered that under the intended conditions of use the risk of allergic sensitisation and elicitation reactions by dietary exposure, although unlikely, cannot be excluded, particularly for individuals sensitised to cedar pollen allergens. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety assessment of the process Cajas y Palets en una Economia Circular (CAPEC), used to recycle high-density polyethylene and polypropylene crates for use as food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Cajas y Palets en una Economia Circular (CAPEC) (EU register number RECYC242). The input consists of crates made of high-density polyethylene (HDPE) or polypropylene (PP) originating from closed and controlled product loops for the packaging of whole fruits and vegetables. Flakes or pellets are produced that will be used by manufacturers of new crates for food contact. The Panel considered that the management system put in place to ensure compliance of the origin of the input with Commission Regulation (EC) No 282/2008 and to provide full traceability from input to final product is the critical process step. It concluded that the input of the process CAPEC originates from product loops which are in closed and controlled chains designed to ensure that only materials and articles that have been intended for food contact are used and that contamination can be ruled out when run under the conditions described by the applicant. The recycling process CAPEC is therefore suitable to produce recycled HDPE and PP crates intended to be used in contact with fruits and vegetables.

Identification and prioritisation for risk assessment of phthalates, structurally similar substances and replacement substances potentially used as plasticisers in materials and articles intended to come into contact with food.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids was requested by the European Commission to re-evaluate the risks to public health related to the presence of plasticisers such as phthalates, structurally similar substances and replacement substances, as a consequence of migration from food contact materials (FCMs). As the first part of the two-part mandate, EFSA was tasked with identifying and prioritising those plasticisers used in FCMs that may warrant further data collection and eventual risk assessment. Close collaboration with the European Chemicals Agency (ECHA) was requested in the mandate. Substances potentially used as plasticisers were identified using Annex II of the mandate, ECHA's PLASI inventory, the Plastics Regulation and the Regenerated Cellulose Film Directive, the ECHA database, the ECHA grouping approach, and consultation with the Member States. Only substances authorised for FCMs at EU or at national level were prioritised. Five substances classified either as carcinogenic, mutagenic, toxic to reproduction Cat. 1 (under CLP) or as endocrine disruptors, persistent, bioaccumulative and toxic, very persistent/very bioaccumulative (under REACH) were placed into an 'exclusion group'. Prioritisation was based on the date of the most recent risk assessment in the context of FCM, with substances assessed before 2001 being placed in the high-priority group, substances assessed between 2001 and 2011 in the medium-priority group and substances assessed after 2011 in the low-priority group. For the EU stream, the 76 substances were split into 59 high-, 14 medium- and 3 low-priority substances. For the nationally authorised stream, the split of the 72 substances is 66, 3 and 3, respectively. The outcome of follow-up calls for data in support of the exposure assessment will be used for a final ranking.

Safety assessment of bleached cellulose pulp for use in plastic food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids assessed the safety of the substance bleached cellulose pulp, consisting of cellulose fibres (70-92%) and hemicellulose (8-30%) obtained from pine and spruce wood. The substance is intended to be used ■■■■■ in polyethylene and polypropylene food contact materials. The final articles are intended to be used for all food types and for long-term storage at room temperature, with or without a short time at higher temperature, including hot-fill. Low-density polyethylene samples containing ■■■■■ of the substance were subjected to a broad set of migration tests with food simulants and extraction tests with dichloromethane. The limits of detection ranged from ■■■■■ (when specified). The Panel noted that they do not ensure the detection of genotoxic substances at a concentration leading to a human exposure above the Threshold of Toxicological Concern. Moreover, not all possibly migrating substances were identified or amenable to the analytical methods applied. No toxicological data were provided for the substance itself, as its migration into food is not expected. The safety of the potentially migrating substances of low molecular mass detected was addressed individually and was considered adequate. However, the Panel considered this approach insufficient owing to a substantial fraction of unidentified components. The Panel concluded that the information provided by the applicant does not allow the safety assessment of the substances below 1,000 Da from bleached cellulose pulp from pine and spruce wood used in plastic food contact materials potentially migrating into food. Therefore, the Panel could not conclude on the safety of the use of bleached cellulose pulp from pine and spruce wood as a plastic additive.

Isolation of Bacterial and Fungal Microbiota Associated with Hermetia illucens Larvae Reveals Novel Insights into Entomopathogenicity.

Larvae of the black soldier fly (BSF) Hermetia illucens are polyphagous feeders and show tremendous bioconversion capabilities of organic matter into high-quality insect biomass. However, the digestion of lignocellulose-rich palm oil side streams such as palm kernel meal (PKM) is a particular challenge, as these compounds are exceptionally stable and are mainly degraded by microbes. This study aimed to investigate the suitability of BSF larvae as bioconversion agents of PKM. Since the intestinal microbiota is considered to play a key role in dietary breakdown and in increasing digestibility, the bacterial and fungal communities of BSF larvae were characterized in a culture-dependent approach and screened for their putative entomopathogenicity. The lethality of six putative candidates was investigated using intracoelomal injection. In total, 93 isolates were obtained with a bacterial share of 74% that were assigned to the four phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Members of the genera Klebsiella, Enterococcus, and Sphingobacterium are part of the core microbiome, as they were frequently described in the gut of Hermetia larvae regardless of diet, nutritional composition, or rearing conditions. With 75%, a majority of the fungal isolates belonged to the phylum Ascomycota. We identified several taxa already published to be able to degrade lignocelluloses, including Enterococcus, Cellulomonas, Pichia yeasts, or filamentous Fusarium species. The injection assays revealed pronounced differences in pathogenicity against the larvae. While Alcaligenes faecalis caused no, Diutina rugosa weak (23.3%), Microbacterium thalassium moderate (53.3%), and Pseudomonas aeruginosa and Klebsiella pneumoniae high (≥80%) lethality, Fusarium solani injection resulted in 100% lethality.

Safety assessment of the process Srichakra Polyplast, based on the Starlinger iV+ technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Srichakra Polyplast (EU register number RECYC229), which uses the Starlinger iV+ technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are dried and crystallised in a first reactor, then extruded into pellets. These pellets are crystallised, preheated and treated in a solid-state polycondensation (SSP) reactor. Having examined the challenge test provided, the Panel concluded that the drying and crystallisation (step 2), extrusion and crystallisation (step 3) and SSP (step 4) are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these critical steps are temperature, air flow and residence time for the drying and crystallisation step, and temperature, pressure and residence time for the extrusion and crystallisation step as well as the SSP step. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 µg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs for long-term storage at room temperature, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process deSter, used to recycle plastic catering tableware for use as food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process deSter (EU register number RECYC196). The input consists of catering tableware food contact articles from airline on-board services, made of polypropylene (PP), polyethylene terephthalate (PET), styrene acrylonitrile resin (SAN) or acrylonitrile butadiene styrene (ABS). The recyclate produced by deSter will be used to manufacture articles for the same on-board services. The Panel considered that the management system put in place to ensure compliance of the origin of the input with Commission Regulation (EC) No 282/2008 and to provide full traceability from input to final product is the critical process step. The process deSter uses only materials and articles intended for food contact and ensures that any contamination can be ruled out, since the input originates from this product loop managed in a closed and controlled chain. Therefore, the Panel concluded that the recycled materials obtained from this process and used within this loop are not of safety concern, when used at up to 100% for the manufacture of plastic tableware for contact with all types of foodstuffs under the conditions of use of the articles before recycling.

Identification of intact peptides by top-down peptidomics reveals cleavage spots in thermolabile wine proteins.

Prevention of haze formation in wines is challenging for winemakers. Thermolabile proteins in wines, notably thaumatin-like proteins (TLPs) and chitinases (CHIs), undergo structural changes under varying physicochemical conditions, resulting in protein aggregation and visible haze in bottled products. Peptidases are an alternative fining method, although an effective proteolysis under typical winemaking conditions (acidic pH and low temperature) is difficult to achieve. In this study, tryptic peptides from TLPs and CHIs were identified by MS-based peptidomics (top-down proteomics) after exposure of scissile bonds on the protein surface. As proposed by the theory of limited proteolysis, protein conformational changes following temperature and pH variations allowed the detection of enzyme-accessible regions. Protein structure visualization and molecular dynamics simulations were used to highlight cleavage spots and provide the scientific basis for haze formation mechanisms. The described method offers a tool to the search for ideal enzymes to prevent wine haze.

Formation of Diastereomeric Dihydromenthofurolactones by Cystostereum murrayi and Aroma Dilution Analysis Based on Dynamic Headspace Extraction.

Submerged cultures of the basidiomycota Cystostereum murrayi emit an intensive coconut-like, sweetish, and buttery smell. For identification of the key aroma compounds, an aroma dilution analysis using dynamic headspace was performed by adjusting the split ratio of the GC inlet system. Flavor dilution (FD) factors varied from 22 up to ≥218, whereby the largest class of compounds represented terpenoids, including two rare stereoisomers of 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (dill ether, ee ≥ 99.9). By means of nuclear magnetic resonance spectroscopy, the substances with the highest FD factors (29, 212, and 218) were identified as diastereomers of 3,6-dimethyl-3a,4,5,6,7,7a-hexayhydro-3H-1-benzofuran-2-one (dihydromenthofurolactone) and as its corresponding C3-unsaturated lactone. The latter two compounds have not been described for Cystostereum murrayi or for any other basidiomycota previously. Supplementation studies using 2-13C-d-glucose indicated that these lactones as well as the two stereoisomers of dill ether and other terpenoids were formed de novo by the fungus.