Staff Publications

Staff Publications

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Evaluating the effect of storage conditions on the shelf life of cape gooseberry (Physalis peruviana L.)
Olivares-Tenorio, Mary Luz ; Dekker, Matthijs ; Boekel, Tiny van; Verkerk, Ruud - \ 2017
Food Science and Technology = Lebensmittel-Wissenschaft und Technologie 80 (2017). - ISSN 0023-6438 - p. 523 - 530.
Ascorbic acid - Fungal growth - Modelling - Shelf life - Survival analysis - β-carotene

Cape gooseberry is the fruit of the plant Physalis peruviana L. and has gained commercial and scientific interest for its contents of health-promoting compounds. An integral approach to estimate shelf life of cape gooseberry was conducted taking into account physicochemical, microbiological and nutritional changes and consumer acceptance. The experiments were performed for 5 independent harvest times during two years (2014–2015). The conditions of storage were temperatures of 4, 8 and 12 °C and a relative humidity of 80%. Fruit with (Y) and without calyx (N) were packed into polyethylene terephthalate (PET) trays and polypropylene (PP) baskets, respectively. The experiment was conducted for a total of 76 d or shorter when the fruit was spoilt earlier. Fruit with the calyx showed a longer shelf life, while 8 °C was the temperature that gave longer shelf lives irrespective of the calyx presence. The critical quality attribute of shelf life without calyx was fungal growth, which determined consumer acceptance; weight loss was the most critical quality attribute for the fruit with calyx. Studying various quality attributes in an integral way appeared to give a better understanding of the shelf life.

Thermal stability of phytochemicals, HMF and antioxidant activity in cape gooseberry (Physalis peruviana L.)
Olivares-Tenorio, Mary Luz ; Verkerk, Ruud ; Boekel, Tiny van; Dekker, Matthijs - \ 2017
Journal of Functional Foods 32 (2017). - ISSN 1756-4646 - p. 46 - 57.
Ascorbic acid - DPPH assay - Flavonoids - Health-promoting compounds - Heat treatment - Modelling - β-carotene
Cape gooseberry is a fruit recognised for having relevant contents of health-promoting compounds. Changes in the content of phytochemicals (ascorbic acid, β-carotene, catechin and epicatechin), hydroxymethylfurfural (HMF) and antioxidant activity of this fruit were studied at various temperatures and times. Ascorbic acid degradation was described by a first order reaction. β-carotene was not degraded and followed an isomerization reaction from 80 °C onwards. Formation of HMF was described with a consecutive zero together with a first order reaction model. The contents of catechin and epicatechin increased at 40 °C. More than three competing reactions did not allow to make kinetic modelling. Antioxidant activity followed fractional first order conversion model. Comparison with kinetics found in other fruits showed that health-promoting compounds of cape gooseberry are relatively more stable to heat treatment. This makes cape gooseberry suitable for the preparation of foods (jam, juices and dehydrated fruit) with relevant health-promoting compounds contents.
Exploring the potential of an Andean fruit : an interdisciplinary study on the cape gooseberry (Physalis peruviana L.) value chain
Olivares Tenorio, Mary Luz - \ 2017
University. Promotor(en): Tiny van Boekel, co-promotor(en): Matthijs Dekker; Ruud Verkerk. - Wageningen : Wageningen University - ISBN 9789462579859 - 190
physalis peruviana - value chain analysis - supply chain management - keeping quality - storage life - storage - phytochemicals - andean group - waardeketenanalyse - ketenmanagement - houdbaarheid (kwaliteit) - bewaartijd - opslag - fytochemicaliën - andesgroep

Cape gooseberry is a fruit cultivated in Andean countries. Currently it is available some international markets, besides the domestic Andean market. Colombia is the major producer and export country at the moment. The value chain of cape gooseberry faces several barriers of technological and governance nature. This research is an interdisciplinary study on the Colombian cape gooseberry value chain. It aimed to evaluate quality attributes of the fruit during the supply chain, including the changes in the contents of health-promoting compounds; and also assessed the current situation of the value chain regarding degree of alignment of the actors.

Findings show that cape gooseberry is a source of health-promoting compounds and has antioxidant activity properties. Such health promoting compounds in cape gooseberry are subject to thermal degradation or formation but not to the extent that they are no longer present after heating. Vitamin C and β-carotene were relative stable after storage time during post-harvest. The main issue for shelf-life of fresh cape gooseberry is the growth of fungi. The intake assessment conducted based on the current consumption of cape gooseberry, concluded that the contribution of this fruit to the daily recommendation intake of vitamin C and β-carotene in Colombian and Dutch adult population is negligible.

Cape gooseberry is indeed a very low consumed fruit because is not well-known in international markets. However, it has potential to improve performance by first facing alignment issues, integrate the value chain and develop strategies to effectively plan the route to follow in order to scale up.

Health-promoting compounds in cape gooseberry (Physalis peruviana L.) : Review from a supply chain perspective
Olivares-Tenorio, Mary Luz ; Dekker, Matthijs ; Verkerk, Ruud ; Boekel, Tiny van - \ 2016
Trends in Food Science and Technology 57 (2016)part A. - ISSN 0924-2244 - p. 83 - 92.
Antioxidant activity - Flavonoids - Phenolic compounds - Phytochemicals - Supply chain - Vitamin C - β-carotene

Background The fruit of Physalis peruviana L., known as Cape Gooseberry (CG) is a source of a variety of compounds with potential health benefits. Therefore, CG has been subject of scientific and commercial interest. Scope and approach This review paper evaluates changes of such health-promoting compounds and antioxidant activity in CG, based on published literature and from a supply chain perspective, considering pre-harvest, post-harvest, processing (thermal and not thermal) and storage steps to give an insight of contents at consumption stage. Key findings and conclusions CG has vitamin C (20 and 35 mg 100 g−1 FW), β-carotene (up to 2.0 mg.100 g−1 FW), total phenolic compounds TPC (50–250 gallic acid equivalents.100 g−1 FW), phenolic acids (caffeic, gallic, chlorogenic, ferulic and p-cumaric acids), flavonoids (quercetin, rutin, myricetin, kaempferol, catechin and epicatechin) and antioxidant activity. There is not yet evidence of presence of physalins and withanolides in CG as previous review papers have stated. The ripeness stage of CG is a relevant factor affecting the content of many phytochemicals. Vitamin C and β-carotene contents are directly proportional to ripeness stage. The reported data in literature showed a large variation, likely caused by different raw material properties (origin, ripeness stage, growing conditions etc.) and differences in the employed analytical methods. Thermal and non-thermal processing have an effect on the extractability of the phytochemicals but also on the decrease of compounds and antioxidant activity. Relative stability to certain phytochemicals to processing suggest an opportunity to add value to supply chain with processed food containing health-promoting compounds.

Human milk composition differs in healthy mothers and mothers with celiac disease
Olivares, M. ; Albrecht, S. ; Palma, G. de; Desamparados Ferrer, M. ; Castillejo, G. ; Schols, H.A. ; Sanz, Y. - \ 2015
European Journal of Nutrition 54 (2015). - ISSN 1436-6207 - p. 119 - 128.
breast-milk - cytokine production - allergic disease - ce-lif - childhood - risk - oligosaccharides - infant - metaanalysis - bacteria
Purpose To investigate whether breast-milk composition and microbiota differ in healthy mothers and mothers with celiac disease (CD) to ultimately contribute to identify additional factors determining CD risk. Methods Breast-milk samples from healthy mothers (n = 12) and mothers with CD (n = 12) were collected. Cytokines and secretory immunoglobulin A (sIgA) were analyzed by bead-arrays and flow cytometry and human milk oligosaccharides (HMOs) were assessed by capillary electrophoresis with laser-induced fluorescence (CE-LIF) detection. Breast-milk microbiota composition was analyzed by conventional and quantitative real-time PCR. Result Breast milk from CD mothers showed significantly lower levels of interleukin (IL) 12p70 (P\\0.042), transforming growth factor (TGF)-b1 (P\\0.018) and sIgA (P\\0.003) and almost significantly lower levels of interferon (IFN)-c (P\\0.058). Six mothers in each group belonged to the secretor Le(a-b?) type, one to the secretor Le(a-b-) type and five to the non-secretor Le(a?b-) type. CD mothers of non-secretor Le(a?b-) type showed increased Lacto-N-tetraose content (P\\0.042) compared with healthy mothers. CD mothers’ milk showed reduced gene copy numbers of Bifidobacterium spp. (P\\0.026) and B. fragilis group (P\\0.044). Conclusion CD mothers’ breast milk is characterized by a reduced abundance of immunoprotective compounds (TGF-b1 and sIgA) and bifidobacteria. The reduction in these components could theoretically diminish the protective effects of breast-feeding on the child’s future risk of developing CD.
Misaligned Preferences And Perceptions On Quality Attributes Of Cape Gooseberry (Physalis Peruviana L) Supply Chain Actors
Olivares-Tenorio, M.L. ; Linnemann, A.R. ; Pascucci, S. ; Verkerk, R. ; Boekel, M.A.J.S. van - \ 2014
In: Conference Proceedings Part 4 International Food Marketing Research Symposium 2014. - Philidelphia, PA : Institiute of Food Products Marketing - ISBN 9780985608026 - p. 106 - 112.
The Cape gooseberry (Physalis peruviana L) is the second most exported fruit in Colombia. The market has grown in the last years due to the interest of consumers in this exotic, good appearance and nutritious fruit. Although, Cape Gooseberry is promising in various aspects, the supply chain still faces some barriers due to, among other factors, the misalignment of preferences and perception of consumers and buyers. The market context in terms of quality attributes of the fruit and their importance in the purchase decision of chain actors is not clear. This project investigates the quality attributes of Cape Gooseberry and their importance for both domestic and international consumers, as well as the actors in the chain that have a purchasing role. This research uses combined methodologies (qualitative and quantitative methods and sensorial evaluation tools) according to the characteristics of the group of actors to evaluate. This study shows that misaligned preferences and perception of actors exist. Focus on globalization of the supply chain is made by involving Colombia as producer of the product and Germany and The Netherlands, which are actual importers.
Responsible Approaches to Genetically Modified Microalgae Production : editorial
Olivares, J. ; Wijffels, R.H. - \ 2013
Algal Research 2 (2013)1. - ISSN 2211-9264 - p. 1 - 1.
Unravelling hazards of nanoparticles to earthworms, from gene to population
Ploeg, M. van der - \ 2013
University. Promotor(en): Ivonne Rietjens, co-promotor(en): Nico van den Brink. - S.l. : s.n. - ISBN 9789461734440 - 192
aardwormen - lumbricus rubellus - nanotechnologie - blootstelling - ecotoxicologie - earthworms - nanotechnology - exposure - ecotoxicology

Nanotechnology is an expeditiously growing field, where engineered nanoparticles are being incorporated in many different applications, from food to waste water treatment (Dekkers et al. 2011; Gottschalk and Nowack 2011; Savage and Diallo 2005). Due to this large scale production and use of nanoparticles, their release into the environment seems inevitable (Crane et al. 2008; Handy et al. 2008a; Oberdörster et al. 2005). Actual exposure levels of nanoparticles under field conditions and the hazards of nanoparticle exposure to the environment are poorly understood, especially for the soil environment (Kahru and Dubourguier 2010; Navarro et al. 2008; Shoults-Wilson et al. 2011a).

Given the need for better characterization of hazards of engineered nanoparticles to the environment and soil organisms in particular, the aim of the present thesis was to investigate effects of nanoparticle exposure on the earthworm Lumbricus rubellus, as a model organism for soil ecotoxicology, and to contribute to the development of effect markers for engineered nanoparticle exposure in this model.

The present thesis was divided in different chapters. Chapter 1 provides an introduction to the topic and discusses the importance of research on the hazards of exposure to engineered nanoparticles. Furthermore, the aim and outline of the thesis are presented, with background information on the model organism, effect markers and nanoparticles.

In chapter 2 effects of exposure to the fullerene C60 (nominal concentrations 0, 15.4 and 154 mg C60/kg soil) on survival and growth during the different life stages of L. rubellus (cocoon, juvenile, subadult and adult), as well as reproduction were quantified. These important individual endpoints for population dynamics were incorporated in a continuous-time life-history model (Baveco and De Roos 1996; De Roos 2008). In this way, effects of C60 exposure on the individual endpoints could be extrapolated to implications for population growth rate and life stage distribution, i.e. the development of the population in terms of number of individuals in the different life stages. These implications at the population level may be more relevant for the ecological impact of C60 than effects on endpoints at the individual level (Klok et al. 2006; Widarto et al. 2004). At the individual level C60 exposure caused significant adverse effects on cocoon production, juvenile growth rate and survival. When these endpoints were used to model effects on the population level, reduced population growth rates with increasing C60 concentrations were observed. Furthermore, a shift in life stage structure was shown for C60 exposed populations, towards a larger proportion of juveniles. This result implies that the lower juvenile growth rate induced by C60 exposure resulted in a larger proportion of juveniles, despite increased mortality among juveniles. Overall, this study implied serious consequences of C60 exposure for L. rubellus earthworm populations, even at the lowest level of exposure tested. Furthermore, it showed that juveniles were more sensitive to C60 exposure than adults.

To complement the observations made on survival, growth and reproduction described in chapter 2, subsequent investigations on cellular and molecular responses of the earthworms to C60 exposure were performed (chapter 3). A set of established effect markers was used, which reflect different levels of biological organisation in the earthworm and may inform on the toxic mechanisms of adverse effects induced by C60 exposure (Handy et al. 2002; Heckmann et al. 2008). At the molecular level, four specific effect markers were selected, including markers for generic stress (heat shock protein 70 (HSP70) (van Straalen and Roelofs 2006), for oxidative stress (catalase and glutathione-S-transferase (GST) (Kohen and Nyska 2002) and for an immune response (coelomic cytolytic factor-1 (CCF-1) (Olivares Fontt et al. 2002). At the tissue level, histological analyses were used to identify damage to cells and tissues, and indications of inflammation in the tissues. In these investigations, exposure to C60 (0, 15 or 154 mg C60/kg soil) affected gene expression of HSP70 significantly. Gene expression of CCF-1 did not alter in adult earthworms exposed for four weeks, but was significantly down-regulated after lifelong exposure (from cocoon stage to adulthood) of earthworms, already to the lowest C60 exposure level. No significant trends were noted for catalase and glutathione-S-transferase (GST) gene expression or enzyme activity. Tissue samples of the C60 exposed earthworms from both experiments and exposure levels, showed a damaged cuticle with underlying pathologies of epidermis and muscles. Additionally, the gut barrier was not fully intact. However, tissue repair was also observed in these earthworms. In conclusion, this study demonstrated effects of sub-lethal C60 exposure on L. rubellus earthworms, at the level of gene expression and tissue integrity.

Although tissue injury is generally associated with an inflammatory response, as part of tissue repair (Cikutovic et al. 1999; Goven et al. 1994), the tissue damage observed for the in vivo C60 exposed earthworms in chapter 3 appeareded to occur without accompanying induced immune responses. The CCF-1 gene expression level was reduced in the C60 exposed earthworms, and histological observations did not show infiltration of damaged tissues by immune cells. In order to obtain further insight in mechanisms of effects observed at the molecular and tissue level on immune related parameters, the sensitivity of immune cells (coelomocytes) of L. rubellus earthworms towards exposure to selected nanoparticles was investigated in vitro (chapter 4). To this end, coelomocytes were isolated from unexposed adult L. rubellus earthworms and exposed to C60 in vitro. After exposure, these coelomocytes were tested for cellular viability, phagocytic activity and CCF-1 gene expression levels. The gene expression of CCF-1 was most affected, demonstrating a strong reduction, which indicated immunosuppression. Experiments with NR8383 rat macrophage cells and tri-block copolymer nanoparticles were used to compare sensitivity of the cell types and showed the usefulness of coelomocytes as a test system for nano-immunotoxicity in general. Overall, this study indicated that the absence of an immune response, in case of tissue injuries observed after in vivo C60 exposure, is likely caused by immunosuppression rather than coelomocyte mortality.

In subsequent investigations, the experiments performed for C60 were also carried out with silver nanoparticles (AgNP), both in vivo and in vitro (chapter 5). Effects of AgNP were assessed in vivo at nominal concentrations of 0, 1.5 (low), 15.4 (medium) and 154 (high) mg Ag/kg soil and compared to effects of silver ions, added as AgNO3 (nominal concentration 15.4 mg Ag/kg soil). In a four week reproduction assay, the high AgNP and AgNO3 treatments had a significant effect on cocoon production and high AgNP exposure also caused a reduction in weight gain of the adult earthworms. No juveniles survived the high AgNP treatment, therefore only F1 earthworms from the other exposure treatments were monitored for survival and growth, until adulthood. These individual endpoints were used to model effects on the population level. The low and medium AgNP as well as the AgNO3 treatments significantly reduced the population growth rate. The high AgNP treatment caused complete failure of the population growth. Furthermore, histological examination of the earthworms from all AgNP exposure treatments demonstrated tissue damage, with injuries mainly at the external barriers, e.g. the cuticle and the gut epithelium. In addition, effects of AgNP exposure were assessed in vitro and a reduction of coelomocyte viability was observed in a concentration-dependent manner, although the EC50 was fourteen times higher compared with that for Ag ions, added as AgNO3. Furthermore, characterisation of the in vivo exposure media implied that AgNP remained present in the soil in single and aggregated state, releasing Ag to the soil pore water up to at least eleven months. The ionic fraction of Ag in soils has been suggested to be bioavailable to organisms and (largely) responsible for the observed AgNP toxicity (Coutris et al. 2012; Koo, et al. 2011; Shoults-Wilson et al. 2011b). In comparison, the AgNO3 seemed to dissolve rapidly, as is also known for this metal salt, and fixation of Ag ions by the soil presumably led to a quick reduction of Ag bioavailability (Atkins and Jones 2000; Coutris et al. 2012; Ratte 1999). This is in line with the observation that effects were more prolonged in the AgNP treatments in comparison with the AgNO3 exposed animals. In conclusion, this study indicated that AgNP exposure may seriously affect earthworm populations, with the ability to cause immunotoxicity, injury to the external barriers of the earthworm body and a reduction in growth, reproduction and juvenile survival.

Finally, chapter 6 presents a discussion on the findings of the present thesis and provides suggestions for future research.

Editorial : Algal Research
Sayre, R. ; Olivares, J. ; Wijffels, R.H. - \ 2012
Algal Research 1 (2012)2. - ISSN 2211-9264 - p. 101 - 101.
Nematodes from the Gulf of California. Part 1. The genera Ceramonema Cobb, 1920, Pselionema Cobb in Cobb, 1933 and Pterygonema Gerlach, 1954 (Nematoda: Ceramonematidae)
Holovachov, O.V. ; Ley, I.T. de; Mundo-Ocampo, M. ; Baldwin, J.G. ; Rocha-Olivares, A. ; Ley, P. de - \ 2008
Nematology 10 (2008)3. - ISSN 1388-5545 - p. 347 - 373.
carinatum chromadorida - liverpool-bay - cuticle
The morphology and morphometry of nematodes of six species of the family Ceramonematidae is described using light and scanning electron microscopy. In this paper, we describe two new species and redescribe two known species of Ceramonema and one new species each of Pselionema and Pterygonema. Ceramonema altogolfi sp. n. is characterised by the 0.8-1.3 mm long body, 187-247 body annules, weakly developed zygapophyses, presence of intracuticular vacuoles, sexual dimorphism in amphid shape, presence of vaginal sclerotisation, complex gubernaculum and relatively uniform anal and cloacal annules, whilst C. inguinispina sp. n. has a 0.8-1.1 mm long body, 135-191 body annules, weakly developed zygapophyses, presence of intracuticular vacuoles, sexual dimorphism in amphid shape, absence of vaginal sclerotisation, thorn-shaped precloacal projection, plate-like gubernaculum and double cloacal annule. Pselionema psednum sp. n. is distinguished by 1.4-1.7 mm long body, 251-292 body annules, weakly developed zygapophyses, absence of intracuticular vacuoles, sexual dimorphism in amphid shape and Pterygonema mexicanum sp. n. is characterised by having amphids lacking a central thorn-like projection and pharynx with a distinct posterior glandular bulb. Populations of Ceramonema rectum and Ceramonema cf. yunfengi are also described. The male cloacal region of the species examined appears to be a rich potential source of taxonomic characters that have as yet received insufficient attention for this family.
Two Lactobacillus strains, isolated from breast milk, differently modulate the immune response
Diaz-Ropero, M.P. ; Martin, R. ; Sierra, S. ; Lara-Villoslada, F. ; Rodriguez, J.M. ; Xaus, J. ; Olivares, M. - \ 2007
Journal of Applied Microbiology 102 (2007)2. - ISSN 1364-5072 - p. 337 - 343.
lactic-acid bacteria - dendritic cells - colonization - enhancement - expression - maturation - probiotics - rhamnosus - diarrhea - flora
Aims: The ability of two different Lactobacillus strains (Lactobacillus salivarius CECT5713 and Lactobacillus fermentum CECT5716), isolated from human breast milk, to modulate the immune response was examined. Methods and Results: In rodent bone-marrow-derived macrophages (BMDM), the presence of Lact. fermentum CECT5716 induced pro-inflammatory cytokines, in contrast to the activation of IL-10 induced by Lact. salivarius CECT5713. Although both strains reduced the lipopolysaccharide (LPS)-induced inflammatory response in BMDM, the effect of Lact. salivarius CECT5713 was more efficient, probably because of the production of higher amounts of IL-10 cytokine. In vivo assays in mice showed similar results; the consumption of Lact. fermentum CECT5716 enhanced the production of Th1 cytokines by spleen cells and increased the IgA concentration in faeces. However, the consumption of Lact. salivarius CECT5713 induced IL-10 production by spleen cells. Conclusion: Therefore, in general, the effect of Lact. fermentum CECT5716 is immunostimulatory in contrast to the anti-inflammatory effect of Lact. salivarius CECT5713. Significance and Impact of the Study: The results of this study show that two Lactobacillus strains isolated from breast milk can exert different and even opposing effects on immune response demonstrating the specificity of each strain.
Safety assessment of two probiotic strains, Lactobacillus coryniformis CECT5711 and Lactobacillus Gasseri CECT5714
Lara-Villoslada, F. ; Sierra, S. ; Martin, R. ; Delgado, S. ; Rodriguez, J.M. ; Olivares, M. ; Xaus, J. - \ 2007
Journal of Applied Microbiology 103 (2007)1. - ISSN 1364-5072 - p. 175 - 184.
lactic-acid bacteria - glycopeptide resistance - susceptibility - vancomycin - diarrhea - sepsis - plasma - milk - pcr
Aims: The object of the present study was to evaluate the oral toxicity of the recently isolated probiotic bacteria Lactobacillus coryniformis CECT5711 and Lactobacillus gasseri CECT5714. Methods and Results: Enzymatic activity and antibiotic resistance profile were evaluated in vitro. Then, the oral toxicity was analysed by an in vivo experiment using 20 Balb/C mice, which were orally treated with CECT5711 or CECT5714 (1010 CFU mouse¿1 day¿1) during 30 days. Results showed that CECT5711 and CECT5714 have no deleterious enzymatic activities and present intrinsic antibiotic resistance profile. Administration of both strains to mice had no adverse effects on body weight or food intake. No bacteraemia was present in liver or spleen and there was no treatment-associated bacterial translocation to these tissues. Liver glutathione content as well as plasma malondialdehide concentration were not statistically different in probiotic-treated mice when compared with control mice. Probiotic treatment did not cause changes in the biochemical and haematological parameters analysed. Conclusions: These results suggest that strains CECT5711 and CECT5714 are nonpathogenic and likely to be safe for human consumption. Significance and Impact of the Study: This study reveals the oral safety of two new lactobacilli strains that are aimed to be used as probiotics in food and pharmaceutical applications.
Involvement of salicylic acid in the establishment of the Rhizobium meliloti-alfalfa symbiosis.
Martinez-Abarca, F. ; Herrera-Cervera, J.A. ; Bueno, P. ; Sanjuan, J. ; Bisseling, T. ; Olivares, J. - \ 1998
Molecular Plant-Microbe Interactions 11 (1998). - ISSN 0894-0282 - p. 153 - 155.
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