R. Mumm - Academia.edu (original) (raw)

Papers by R. Mumm

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In recent years green mould (Trichoderma aggressivum) has presented big problems to the Dutch mus... more In recent years green mould (Trichoderma aggressivum) has presented big problems to the Dutch mushroom industry. T. aggressivum infects compost at a very early stage and in the Dutch situation infection most likely takes place at the compost yard. Even though compost producers in the Netherlands are very keen to prevent green mould problems, occasionally still a number of crops get infected. Therefore there is a need for a reliable method that allows early detection of Trichoderma green mould. Although qPCR methods have been developed for quantitation of T. aggressivum, these cannot be used for detection in compost. In the Netherlands spawn run is performed in bulk at the compost yards and is referred to as phase 3 composting. During this process, spawned compost is incubated in tunnels and ventilated with large volumes of air to control compost temperature. During this process the compost is inaccessible for sampling. Literature data showed that Agaricus bisporus and T. aggressivum use volatiles to affect each other's growth rate. We tested the possibility to detect Trichoderma green mould using the volatiles that are emitted during spawn run. This eventually could lead to a sophisticated noninvasive detection method of T. aggressivum in the process air of the tunnels, without the need to sample inside the tunnel during spawn run. For this we compared volatiles that are produced in non-infected compost with volatiles that are produced in infected compost. In our experimental model, 300 g of phase 2 compost, is spawned and inserted in aerated glass vessels. Compost is colonised at an air temperature of 24°C. After 7, 10 and 14 days of spawn run, process air is sampled both in infected and noninfected cultures and analysed by coupled gas chromatography mass spectrometry (GC-MS). During this 14-day period white mushroom mycelium develops in the non-infected compost. In the infected compost the compost turns black with occasional tufts of white mycelium and green spores. Volatile blends that are produced during normal compost colonisation (when Agaricus bisporus interacts with Scytalidium thermophilum and other micro flora present in compost) differ from those produced during colonisation of T. aggressivum infected compost. Some of the volatiles appear to be specific for T. aggressivum infected compost. Next to this also consistent differences in the overall pattern of volatile production are seen. Infections with T. harzianum, T. atroviride, an Aspergillus species, or Smokey mould (Penicillium citreonigrum) produce different volatile patterns. Significant differences between the volatile blends of infected and non-infected compost are visible after 7 days of compost colonisation. In commercial practice of phase 3 composting, tunnels are likely to be partially infected. Ongoing research is directed at studying larger amounts of compost that is only partially infected.

Journal of Agricultural and Food Chemistry, 2020

Soy sauce is a fermented product, and its flavor is a complex mixture of individual senses which,... more Soy sauce is a fermented product, and its flavor is a complex mixture of individual senses which, in combination, create a strong palatable condiment for many Eastern and Western dishes. This Review focuses on our existing knowledge of the chemical compounds present in soy sauce and their potential relevance to the flavor profile. Taste is dominated by umami and salty sensations. Free amino acids, nucleotides, and small peptides are among the most important taste-active compounds. Aroma is characterized by caramel-like, floral, smoky, malty, and cooked potato-like odors. Aroma-active volatiles are chemically diverse including acids, alcohols, aldehydes, esters, furanones, pyrazines, and S-compounds. The origin of all compounds relates to both the raw ingredients and starter cultures used as well as the parameters applied during production. We are only just starting to help develop innovative studies where we can combine different analytical platforms and chemometric analysis to link flavor attributes to chemical composition.

LWT, 2021

Traditional hot air drying of asparagus is known to lead to a powder with a poor aroma profile. W... more Traditional hot air drying of asparagus is known to lead to a powder with a poor aroma profile. We here concentrated asparagus juice into asparagus concentrate (21.7% w/w) and spray-dried it with maltodextrin DE12 as carrier agent to improve the volatile profiles of asparagus powder and to valorise fresh asparagus sidestreams. We performed headspace GC-MS with untargeted metabolomics to assess the overall metabolite profile of the spray-dried asparagus powders and identified 70 volatile compounds. The maltodextrin content was positively correlated to the retention of an asparagus key odorant 1-octen-3-ol, as well as other alcohols and aldehydes. Nevertheless, drying conditions had limited effect on the volatile retention of the powders. Moreover, higher outlet temperatures increase the presence of volatiles that were formed during drying, such as 3-methylthio-propanal. From our analyses, it was further found that an increased concentration of maltodextrin was correlated to a lower moisture content, a higher glass transition temperature (T g) and a narrower size distribution of the spray-dried powders. The T g of all powders was described with the Gordon-Taylor equation for multicomponent mixtures, and we found a minimum weight fraction of 0.67 (w/dw) maltodextrin required to obtain glassy asparagus powder for storing at ambient conditions.

Tree Physiology, 2020

It is well known that green tea made from fully developed leaves located at the base of young s... more It is well known that green tea made from fully developed leaves located at the base of young shoots is of lower quality than that made from the still developing leaves located on the top of the shoot. It has additionally been shown that plant shading can significantly improve green tea quality. Here, we aimed to get more insight into the effects of shading on the overall metabolome in different parts of the tea shoots. To do this, field-grown tea plants were shaded by coverage with either a straw layer or a black net, both blocking the daylight intensity for more than 90%. Both the first (i.e. still developing) leaf and the fourth (i.e. fully developed) leaf, as well as the stem of young shoots were harvested and subjected to complementary untargeted metabolomics approaches, using accurate mass LC-Orbitrap-Fourier transform mass spectrometry (FTMS) for profiling both semi-polar and lipid-soluble compounds and GC-TOF-MS for profiling polar compounds. In total, 1419 metabolites wer...

Food Chemistry, 2022

Wholemeal flours from blends of bread wheat, emmer and spelt were processed into bread using yeas... more Wholemeal flours from blends of bread wheat, emmer and spelt were processed into bread using yeast-based and sourdough fermentation. The bread wheat flour contained significantly higher concentrations of total dietary fibre and fructans than the spelt and emmer flours, the latter having the lowest contents. Breadmaking using sourdough and yeast systems resulted in changes in composition from flour to dough to bread including increases in organic acids and mannitol in the sourdough system and increases in amino acids and sugars (released by hydrolysis of proteins and starch, respectively) in both processing systems. The concentrations of fructans and raffinose (the major endogenous FODMAPs) were reduced by yeast and sourdough fermentation, with yeast having the greater effect. Both systems resulted in greater increases in sugars and glycerol in emmer than in bread wheat and spelt, but the significance of these differences for human health has not been established.

During the last 35 years, hardly any breeding has been done in the button mushrooms (Agaricus bis... more During the last 35 years, hardly any breeding has been done in the button mushrooms (Agaricus bisporus). The fact that no new varieties are generated directed to trends in the food market has caused a slowly decrease in mushroom consumption in the Netherlands and in Europe. The hurdles for generating new varieties are difficulties in breeding and protection of new varieties. These hurdles are now nearly tackled and it is time to generate new varieties. One issue that has never been addressed is taste. The collection of Plant Breeding Wageningen UR contains a large number of strains of the button mushroom with a large genetic variation. In previous research this collection has been genotyped and a small selection of genetically different strains has been made. In 2014 these strains were cultivated along two different methods that were likely to cause differences in taste. Atempts were made to link the results from the taste panel to the metabolite concentrations. Even though it is a ...

Revista de Ciências Agrárias, 2019

In order to identify volatile organic compounds (VOCs) attractive to Epitrix spp. adults, field a... more In order to identify volatile organic compounds (VOCs) attractive to Epitrix spp. adults, field and laboratory experiments were carried out in sequence. In the field, black nightshade potted plants attracted significantly more Epitrix spp. adults than potato, aubergine, tomato and common lambsquarters. Following this result, headspace samples were collected from non-infested and from E. papa infested plants of potato, aubergine and black nightshade. VOC profiling by GC-MS analysis identified potential attractants which were tested as single compounds or as a mixture in a field experiment (1,3-butanediol, Z3-6:Ac/Linalool (1:1), (E)-β-farnesene and a blank control). Traps baited with Z3-6:Ac/ Linalool (1:1) attracted significantly more E. papa and E. cucumeris adults than the control. To find synergist substances to improve the attractiveness of this mixture, the choice of individual E. papa adults between this mixture alone or combined with several other plant VOCs, was sequentially...

Journal of Chemical Ecology, 2019

Aggregation of the bean flower thrips, Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae... more Aggregation of the bean flower thrips, Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), has been observed on cowpea, Vigna unguiculata (L.) Walp. To understand the mechanism underpinning this behavior, we studied the responses of M. sjostedti to headspace volatiles from conspecifics in a four-arm olfactometer. Both male and female M. sjostedti were attracted to male, but not to female odor. Gas chromatography/mass spectrometry (GC/ MS) analyses revealed the presence of two distinct compounds in male M. sjostedti headspace, namely (R)-lavandulyl 3-methylbutanoate (major compound) and (R)-lavandulol (minor compound); by contrast, both compounds were only present in trace amounts in female headspace collections. A behavioral assay using synthetic compounds showed that male M. sjostedti was attracted to both (R)-lavandulyl 3-methylbutanoate and (R)-lavandulol, while females responded only to (R)-lavandulyl 3-methylbutanoate. This is the first report of a male-produced aggregation pheromone in the genus Megalurothrips. The bean flower thrips is the primary pest of cowpea, which is widely grown in sub-Saharan Africa. The attraction of male and female M. sjostedti to these compounds offers an opportunity to develop ecologically sustainable management methods for M. sjostedti in Africa.

Phytochemistry, 2014

Volatile organic compound (VOC) Aroma Amino acid Thermal desorption (TD) Solid phase micro extrac... more Volatile organic compound (VOC) Aroma Amino acid Thermal desorption (TD) Solid phase micro extraction (SPME) Gas chromatography mass spectrometry (GC-MS) Proton-nuclear magnetic resonance spectroscopy (1 H NMR) Metabolomics a b s t r a c t Cucumis melo fruit is highly valued for its sweet and refreshing flesh, however the flavour and value are also highly influenced by aroma as dictated by volatile organic compounds (VOCs). A simple and robust method of sampling VOCs on polydimethylsiloxane (PDMS) has been developed. Contrasting cultivars of C. melo subspecies melo were investigated at commercial maturity: three cultivars of var. Cantalupensis group Charentais (cv. Cézanne, Escrito, and Dalton) known to exhibit differences in ripening behaviour and shelf-life, as well as one cultivar of var. Cantalupensis group Ha'Ogan (cv. Noy Yisre'el) and one non-climacteric cultivar of var. Inodorus (cv. Tam Dew). The melon cultivar selection was based upon fruits exhibiting clear differences (cv. Noy Yisre'el and Tam Dew) and similarities (cv. Cézanne, Escrito, and Dalton) in flavour. In total, 58 VOCs were detected by thermal desorption (TD)-GC-MS which permitted the discrimination of each cultivar via Principal component analysis (PCA). PCA indicated a reduction in VOCs in the non-climacteric cv. Tam Dew compared to the four Cantalupensis cultivars. Within the group Charentais melons, the differences between the short, mid and long shelf-life cultivars were considerable. 1 H NMR analysis led to the quantification of 12 core amino acids, their levels were 3-10-fold greater in the Charentais melons, although they were reduced in the highly fragrant cv. Cézanne, indicating their role as VOC precursors. This study along with comparisons to more traditional labour intensive solid phase micro-extraction (SPME) GC-MS VOC profiling data has indicated that the high-throughput PDMS method is of great potential for the assessment of melon aroma and quality.

Plant Physiology, 2012

Recent advances in -omics technologies such as transcriptomics, metabolomics, and proteomics alon... more Recent advances in -omics technologies such as transcriptomics, metabolomics, and proteomics along with genotypic profiling have permitted dissection of the genetics of complex traits represented by molecular phenotypes in nonmodel species. To identify the genetic factors underlying variation in primary metabolism in potato (Solanum tuberosum), we have profiled primary metabolite content in a diploid potato mapping population, derived from crosses between S. tuberosum and wild relatives, using gas chromatography-time of flight-mass spectrometry. In total, 139 polar metabolites were detected, of which we identified metabolite quantitative trait loci for approximately 72% of the detected compounds. In order to obtain an insight into the relationships between metabolic traits and classical phenotypic traits, we also analyzed statistical associations between them. The combined analysis of genetic information through quantitative trait locus coincidence and the application of statistical...

Journal of Experimental Botany, 2009

Caterpillar feeding induces direct and indirect defences in brassicaceous plants. This study focu... more Caterpillar feeding induces direct and indirect defences in brassicaceous plants. This study focused on the role of the octadecanoid pathway in induced indirect defence in Brassica oleracea. The effect of induction by exogenous application of jasmonic acid (JA) on the responses of Brussels sprouts plants and on host-location behaviour of associated parasitoid wasps was studied. Feeding by the biting-chewing herbivores Pieris rapae and Plutella xylostella resulted in significantly increased endogenous levels of JA, a central component in the octadecanoid signalling pathway that mediates induced plant defence. The levels of the intermediate 12-oxophyto-dienoic acid (OPDA) were significantly induced only after P. rapae feeding. Three species of parasitoid wasps, Cotesia glomerata, C. rubecula, and Diadegma semiclausum, differing in host range and host specificity, were tested for their behavioural responses to volatiles from herbivore-induced, JA-induced, and non-induced plants. All three species were attracted to volatiles from JA-induced plants compared with control plants; however, they preferred volatiles from herbivore-induced plants over volatiles from JA-induced plants. Attraction of C. glomerata depended on both timing and dose of JA application. JA-induced plants produced larger quantities of volatiles than herbivore-induced and control plants, indicating that not only quantity, but also quality of the volatile blend is important in the hostlocation behaviour of the wasps.

Journal of Chemical Ecology, 2009

During mating in many butterfly species, males transfer spermatophores that contain anti-aphrodis... more During mating in many butterfly species, males transfer spermatophores that contain anti-aphrodisiacs to females that repel conspecific males. For example, males of the large cabbage white, Pieris brassicae (Lepidoptera: Pieridae), transfer the anti-aphrodisiac, benzyl cyanide (BC) to females. Accessory reproductive gland (ARG) secretion of a mated female P. brassicae that is deposited with an egg clutch contains traces of BC, inducing Brussels sprouts plants (Brassica oleracea var. gemmifera) to arrest certain Trichogramma egg parasitoids. Here, we assessed whether deposition of one egg at a time by the closely related small cabbage white, Pieris rapae, induced B. oleracea var. gemmifera to arrest Trichogramma wasps, and whether this plant synomone is triggered by substances originating from male P. rapae seminal fluid. We showed that plants induced by singly laid eggs of P. rapae arrest T. brassicae wasps three days after butterfly egg deposition. Elicitor activity was present in ARG secretion of mated female butterflies, whereas the secretion of virgin females was inactive. Pieris rapae used a mixture of methyl salicylate (MeSA) and indole as an anti-aphrodisiac. We detected traces of both anti-aphrodisiacal compounds in the ARG secretion of mated female P. rapae, whereas indole was lacking in the secretion of virgin female P. rapae. When applied onto the leaf, indole induced changes in the foliar chemistry that arrested T. brassicae wasps. This study shows that compounds of male seminal fluid incur possible fitness costs for Pieris butterflies by indirectly promoting egg parasitoid attack.

Forensic Science International, 2012

Journal of Experimental Biology, 2005

SUMMARYEgg deposition by the phytophagous sawfly Diprion pini L.(Hymenoptera, Diprionidae) is kno... more SUMMARYEgg deposition by the phytophagous sawfly Diprion pini L.(Hymenoptera, Diprionidae) is known to induce locally and systemically the emission of volatiles in Scots pine (Pinus sylvestris L.) that attract the egg parasitoid Chrysonotomyia ruforum Krausse(Hymenoptera, Eulophidae). The egg parasitoids kill the eggs and thus prevent damage to the plant from feeding sawfly larvae. The elicitor inducing the pine's response is known to be located in the oviduct secretion which the female sawfly applies to the eggs when inserting them into a slit in the pine needle using the sclerotized ovipositor valves. In this study we have characterized the elicitor. The elicitor was still active when isolated from the oviduct and applied directly to slits made in the pine needles. However,as soon as the oviduct secretion was dissolved in Aqua dest. and stored for 3 h at room temperature or kept frozen at -80°C, its activity was lost. In contrast, oviduct secretion kept its eliciting activity,...

Proceedings of the National Academy of Sciences, 2008

Plants can recruit parasitic wasps in response to egg deposition by herbivorous insects–a sophist... more Plants can recruit parasitic wasps in response to egg deposition by herbivorous insects–a sophisticated indirect plant defense mechanism. Oviposition by the Large Cabbage White butterfly Pieris brassicae on Brussels sprout plants induces phytochemical changes that arrest the egg parasitoid Trichogramma brassicae . Here, we report the identification of an elicitor of such an oviposition-induced plant response. Eliciting activity was present in accessory gland secretions released by mated female butterflies during egg deposition. In contrast, gland secretions from virgin female butterflies were inactive. In the male ejaculate, P. brassicae females receive the anti-aphrodisiac benzyl cyanide (BC) that reduces the females' attractiveness for subsequent mating. We detected this pheromone in the accessory gland secretion released by mated female butterflies. When applied onto leaves, BC alone induced phytochemical changes that arrested females of the egg parasitoid. Microarray analyse...

Metabolomics is a proven tool to obtain information about differences in food stuffs and to selec... more Metabolomics is a proven tool to obtain information about differences in food stuffs and to select biochemical markers for sensory quality of food products. A valuable application of untargeted metabolomics is the selection of metabolites that are (highly) predictive for sensory or phenotypical traits for use as (bio) markers. This chapter demonstrates how to robustly select key metabolites and evaluate their predictive properties. The proposed approach constrains the number of selected metabolites, searching for an optimal number of predictive metabolites by cross-validation. This mitigates the problem of selection of spurious metabolites. It also enables straightforward use of linear regression. In the present implementation simple forward selection is used. In concert with a second cross-validation to assess the predictive power of the selected set of metabolites, the proposed method involves two leave-one-out cross-validations and will be referred to as LOO2CV. In the second lea...