Styrian Pumpkin Research Articles

Securing food authenticity by translating triacylglycerol profiles of edible oils into a versatile identification method for pumpkin seed oil adulteration

Edible plant oils provide a crucial source of lipids for human nutrition. Owing to the complex processing of some high-quality variants, including Styrian pumpkin seed oil, edible plant oils have become susceptible to food fraud by adulteration with cheaper vegetable oils, compromising both authenticity and quality. To address this issue, a workflow was developed utilizing QTOF-MS/MS to search for triacylglycerol markers indicative of adulteration and subsequently adapted them for routine analysis using triple quadrupole MS/MS. By developing a transparent classification system utilizing a multi-feature triacylglycerol panel, reliable detection of adulteration down to 3 % (w/w) is possible. Calculating ratios of selected markers and establishing intervals derived from pure oils further enables easy scalability to adjust marker ratios and ensure robustness against permanent or seasonal changes. Our work aims to make advances towards a rapid and accurate detection of oil adulteration in food industry, crucial for maintaining customer trust and safety.

Effect of plant protein extrudates on hybrid meatballs – Changes in nutritional composition and sustainability

To feed the world's growing population in the future, there must be a protein transition from animal-based to more sustainable, plant-based sources. Hybrid plant-meat products can bridge the protein-transition and are also focused on nutritional and sustainability aspects. While the addition of powdered proteins changes the texture of meat products, textured proteins have been shown to achieve higher sensorial acceptability. Six hybrid pork meatballs, each made with 30% wet or dry textured protein from regional pea, sunflower or Styrian pumpkin seeds and canola oil, were produced and analyzed for their fatty acid, amino acid and sustainability changes compared to respective controls. All hybrids had a higher content in essential linoleic and α-linolenic acid, an improved ω-6:ω-3 ratio and the hypothetic content in dietary fibers increased. On the contrary, the hypothetic protein digestibility-corrected amino acid score for children and therefore protein quality of the hybrids was slightly reduced, albeit high in comparison to the plant-based raw materials. The environmental impact of all hybrids was reduced in a protein- and texturization-dependent manner. Wet texturization seemed to be more sustainable than dry texturization. We conclude that textured plant proteins are a promising additive to produce meat hybrids with improved texture, nutritional composition and sustainability.

α-Linolenic acid and product octadecanoids in Styrian pumpkin seeds and oils: How processing impacts lipidomes of fatty acid, triacylglycerol and oxylipin molecular structures

Styrian pumpkin seed oil is a conditioned green-colored oil renowned for nutty smell and taste. Due to α-linolenic acid (ALA) contents below 1% of total fatty acids and the prospect of nutritional health claims based on its potential oxidation products, we investigated the fate of ALA and product oxylipins in the course of down-stream processing of seeds and in oils. Lipidomic analyses with Lipid Data Analyzer 2.8.1 revealed: Processing did not change (1) main fatty acid composition in the oils, (2) amounts of triacylglycerol species, (3) structures of triacylglycerol molecular species containing ALA. (4) Minor precursor ALA in fresh Styrian and normal pumpkins produced 6 product phytoprostanes in either cultivar, quantitatively more in the latter. (5) In oil samples 7 phytoprostanes and 2 phytofurans were detected. The latter two are specific for their presence in pumpkin seed oils, of note, quantitatively more in conditioned oils than in cold-pressed native oils.

Parthenogenetic Haploid Plant Production in Styrian Pumpkin by Gamma Irradiated Pollen

Doubled haploid method via parthenogenesis induction still remained prominent in Cucurbitaceae breeding due to drastic reduction in time and cost of newly released lines. In this study, different doses of Gamma ray (25, 50, 75, 100, and 200 Gy) were used to irradiate pollen grains for induction of parthenogenetic haploid embryos in oilseed pumpkin (Cucurbita pepo var. ‘Styriaca’). Parthenogenetic embryos at different developmental stages were rescued in vitro and 348 plants were obtained, of which 134 were recognized as haploid by ploidy analysis. The highest rate of haploid plants was obtained from globular (25.3%) and torpedo (23.8% plants) embryos followed by arrow-tip (13.4%), torpedo (10.5%), stick (10.5%), heart (9%), and cotyledonary (7.5%), respectively. All doses, except 200 Gy, were effective for induction of embryos and haploid plants; in a way that the highest number of haploids was obtained by 100 Gy. Our results indicated that parthenogenetic haploid embryos could be efficiently induced in C. pepo if proper Gamma ray dose and developmental stage of embryos are selected.

Seed Lipid Composition of New Hybrids of Styrian Oil Pumpkin Grown in Poland

Styrian hull-less pumpkins are valued for their use in health-promoting foods such as oils and snacks. Although deriving from Styria, they are now cultivated globally. Seeds of Styrian oil pumpkins are rich in lipids and represent a high-value product. Thus, seed yield and quality are traits of economic importance. These seed characteristics depend mostly on the cultivated variety and plant growing conditions. This study aimed to assess the variation in hull-less seed lipids of new hybrids of Styrian oil pumpkin developed recently for cultivation in moderate/colder climate zones of the north-eastern part of Poland. The study showed that the newly-developed hybrids have a relatively high content of total lipids in seeds, with a substantially higher share of linoleic acid (up to 63%). However, sterols, tocopherols, and squalene content and composition were similar to pumpkin seed oils produced from plants cultivated in other, warmer regions. This study provides insights into the chemical composition of Styrian pumpkin oil produced from hybrids grown under the relatively severe climatic conditions of north-eastern Poland.

Can chemometrics protect pumpkin seed oil buyers from false Styrian PGI labels?

A group of scientists from Loeben Universtity is proposing the use of chemometrics in the detection of authenticity of Styrian PGI pumpkin seed oil. They have shown that pumpkin seeds from Austria and foreign countries differ in the composition of various element traces. Based on that they are able to differentiate between false and authentic PGI pumpkin seed using mathematical modeling.

Chemometric techniques to protect the traditional Austrian pumpkin seed oil

The aim of this work was to establish suitable chemometric techniques for establishing provenance of pumpkin seed and pumpkin seed oil from the regions of Austria, China and Russia, in order to protect the authentic Austrian products from fraud and mislabelling. To achieve this goal, three different chemometric approaches, projection to latent structures (PLS), soft independent modelling of class analogy (SIMCA) and support vector machines (SVM) were applied on two different trace element data sets. To evaluate the reliability of the classification achieved, the results were validated on an independent test set. PLS and SVM performed similarly in many situations. Also the prediction of the discriminating techniques was in accordance with the modelling technique SIMCA. But PLS alone can be used to separate Austrian from non‐Austrian pumpkin seed and pumpkin seed oil samples based on trace element data.Practical applications: For various reasons, more and more consumers prefer local products with a defined geographical origin. Producers also advertise the geographical origin and are trying to increase the value of their products by praising the quality of their products through a geographical designation. Unfortunately, there is an increases of abuse in these products which also comprise the ‘Styrian pumpkin seed oil PGI’ with falsely declared geographical origin. The demand for an analytical approach how to counteract the falsification of origin of Styrian pumpkin seed oil has increased considerably. The aim of this work is to establish an analytical method with suitable chemometric techniques for establishing the provenance of pumpkin seed oil from the regions of Austria, China and Russia, in order to protect the authentic Austrian products from fraud and mislabelling.PLS, SIMCA and SVM chemometric techniques are applied for establishing the provenance of pumpkin seed and pumpkin seed oil. PLS and SVM perform similarly in most situations and are in accordance with SIMCA models. However, the classification task can be solved by PLS only.

Pumpkin seed extract: Cell growth inhibition of hyperplastic and cancer cells, independent of steroid hormone receptors

Pumpkin seeds have been known in folk medicine as remedy for kidney, bladder and prostate disorders since centuries. Nevertheless, pumpkin research provides insufficient data to back up traditional beliefs of ethnomedical practice. The bioactivity of a hydro-ethanolic extract of pumpkin seeds from the Styrian pumpkin, Cucurbita pepo L. subsp. pepo var. styriaca, was investigated. As pumpkin seed extracts are standardized to cucurbitin, this compound was also tested. Transactivational activity was evaluated for human androgen receptor, estrogen receptor and progesterone receptor with in vitro yeast assays. Cell viability tests with prostate cancer cells, breast cancer cells, colorectal adenocarcinoma cells and a hyperplastic cell line from benign prostate hyperplasia tissue were performed. As model for non-hyperplastic cells, effects on cell viability were tested with a human dermal fibroblast cell line (HDF-5). No transactivational activity was found for human androgen receptor, estrogen receptor and progesterone receptor, for both, extract and cucurbitin. A cell growth inhibition of ~40–50% was observed for all cell lines, with the exception of HDF-5, which showed with ~20% much lower cell growth inhibition. Given the receptor status of some cell lines, a steroid-hormone receptor independent growth inhibiting effect can be assumed. The cell growth inhibition for fast growing cells together with the cell growth inhibition of prostate-, breast- and colon cancer cells corroborates the ethnomedical use of pumpkin seeds for a treatment of benign prostate hyperplasia. Moreover, due to the lack of androgenic activity, pumpkin seed applications can be regarded as safe for the prostate.

Characterization of the Aroma Signature of Styrian Pumpkin Seed Oil (Cucurbita pepo subsp. pepo var. Styriaca) by Molecular Sensory Science

Application of the aroma extract dilution analysis on a distillate prepared from an authentic Styrian pumpkin seed oil followed by identification experiments led to the characterization of 47 odor-active compounds in the flavor dilution (FD) factor range of 8-8192 among which 2-acetyl-1-pyrroline (roasty, popcorn-like), 2-propionyl-1-pyrroline (roasty, popcorn-like), 2-methoxy-4-vinylphenol (clove-like), and phenylacetaldehyde (honey-like) showed the highest FD factors. Among the set of key odorants, 2-propionyl-1-pyrroline and another 20 odorants were identified for the first time as constituents of pumpkin seed oil. To evaluate the aroma contribution in more detail, 31 aroma compounds showing the highest FD factors were quantitated by means of stable isotope dilution assays. On the basis of the quantitative data and odor thresholds determined in sunflower oil, odor activity values (OAV; ratio of concentration to odor threshold) were calculated, and 26 aroma compounds were found to have an OAV above 1. Among them, methanethiol (sulfury), 2-methylbutanal (malty), 3-methylbutanal (malty), and 2,3-diethyl-5-methylpyrazine (roasted potato) reached the highest OAVs. Sensory evaluation of an aroma recombinate prepared by mixing the 31 key odorants in the concentrations as determined in the oil revealed that the aroma of Styrian pumpkin seed oil could be closely mimicked. Quantitation of 11 key odorants in three commercial pumpkin seed oil revealed clear differences in the concentrations of distinct odorants, which were correlated with the overall aroma profile of the oils.

Identification of the geographical origin of pumpkin seed oil by the use of rare earth elements and discriminant analysis

The aim of this work was to develop an analytical method to assure the geographical origin of Styrian pumpkin seed oil, a high priced local product which is protected by the European Union. The development of such a method is not only of interest for scientists but also of importance for producer that want to guarantee the purity and quality of their products as well as the consumer wanting to know the origin of the food products. Since the rare earth elements (REE) concentrations are extremely low in pumpkin seed oil a fast and sensitive analytical method with ICP-MS had to be developed and validated. In the current project, pumpkin seeds from different regions in Austria were sampled. The REE patterns in the extracted oil of these seeds were determined and a preliminary classification with discriminant analysis was successfully done on a statistical basis. The study demonstrates that pumpkin seed oils from different geographical origin show variable rare earth element patterns making it possible to trace the origin of these oils.

Production technology and characteristics of Styrian pumpkin seed oil

AbstractCucurbita pepo subsp. pepo var. Styriaca, the so‐called Styrian oil pumpkin, is a phylogenetically young member of the Cucurbita spp. A single mutation occurred only in the 19th century and led to dark green seeds with stunted outer hulls. This mutation facilitated the production of Styrian pumpkin seed oil that became a regional specialty oil in the south‐eastern part of Europe during the last few decades. We describe in this article the production and economic value of this edible specialty oil as well as the most important parameters relevant for its quality. Furthermore, we report on its molecular composition including fatty acids, vitamins, phytosterols, minerals, polyphenols, and those compounds that are responsible for its color, taste and flavor. Finally, information is provided on potential contaminants of Styrian pumpkin seed oil as well as its putative beneficial health effects.

Seeds and oil of the Styrian oil pumpkin: Components and biological activities

AbstractCucurbita pepo subsp. pepo var. Styriaca is a phylogenetically young member of the Cucurbita spp. since the mutation leading to dark green seeds with stunted outer hulls arose only in the 19th century. This mutation defined the so‐called Styrian oil pumpkin and facilitated the production of Styrian pumpkin seed oil. It is a regional specialty oil in the south‐eastern part of Europe. In this article, we describe the production and economic value of this edible oil as well as its composition on a molecular basis, including fatty acids, vitamins, phytosterols, minerals, polyphenols, and the compounds responsible for its pigments, taste and flavor. We also describe contaminants of Styrian pumpkin seed oil and the most relevant field pests of the Styrian oil pumpkin plant. Finally, we review the putative beneficial health effects of Styrian oil pumpkin seeds and of their products.

Changes in the Subcellular Distribution of Glutathione during Virus Infection in Cucurbita pepo (L.)

Changes in the subcellular distribution and quantification of glutathione were studied with electron microscopic immunogold cytochemistry in Zucchini yellow mosaic virus (ZYMV)-infected Styrian pumpkin plants (Cucurbita pepo L. ssp. pepo var. styriaca Greb.) two weeks after inoculation. The amount of gold particles bound to glutathione was statistically evaluated for different cell structures, including mitochondria, plastids, nuclei, peroxisomes, and cytosol. In general, ZYMV-infected plants showed higher gold labelling density in intact mesophyll cells of the 5th (older leaves) and the youngest fully developed leaves (younger leaves), and decreased levels of glutathione within root tip cells when compared to the control. In general, within older and younger leaves the highest amount of gold particles was found in mitochondria and the lowest amount in plastids. In ZYMV-infected older leaves, an increase in glutathione was found in peroxisomes (1.7-fold), the cytosol (1.6-fold), mitochondria (1.4-fold), and nuclei (1.2-fold), whereas glutathione levels in plastids did not differ significantly when compared to control cells. In ZYMV-infected younger leaves elevated glutathione contents were found in the cytosol (3-fold), nuclei (2.1-fold), peroxisomes (1.8-fold), and plastids (1.5-fold), whereas mitochondria showed an insignificant decrease in glutathione levels in comparison to the control. In root tip cells of ZYMV-infected plants the amount of gold particles bound to glutathione was decreased in all investigated cell structures by between 0.7- to 0.8-fold. Additionally, total glutathione contents were determined in older and younger leaves using high-performance liquid chromatography (HPLC), which revealed no significant differences between control and ZYMV-infected leaves. The relevance of the results of both methods were compared and are discussed.

Plant regeneration via somatic embryogenesis in Styrian pumpkin: cytological and biochemical investigations

Somatic embryo formation was induced from cotyledon explants of Styrian pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) by using a solid MS medium supplemented with 16.11 μM NAA and 4.44 μM BA or 26.85 μM NAA and 13.32 μM BA. The callus proliferation was more efficient on medium supplemented with 26.85 μM NAA and 13.32 μM BA. In contrast, the embryogenic response was higher on medium with lower concentrations of growth regulators (16.11 μM NAA and 4.44 μM BA). The time needed for embryo induction did not depend on medium composition. Embryos in globular stage were transferred to three different maturation media, containing 2.89 μM GA3 in combination with 0.54 μM NAA, 11.42 μM IAA and growth regulator-free medium. The germination rate was the highest when embryos were cultured on medium with 11.42 μM IAA. Plantlets grown on this medium achieved maturity suitable for transplantation into soil within 9 to 10 weeks. The regenerated plants were successfully transferred into field and developed fertile flowers and set fruits. Biochemical analysis showed significant lower total glutathione levels among in vitro grown plantlets compared to seedlings grown in soil. When the plantlets were transferred into soil, they reached a normal size within a month and the glutathione concentration was comparable to seed-derived plants at the same developmental stage. Transmission electron microscopy was used to investigate possible differences in the ultrastructure of cells from callus cultures, and leaf cells of regenerated and seed-derived plants. Differences in the ultrastructure were found within chloroplasts which contained only single thylakoids, large starch grains and small plastoglobuli in callus cells in comparison to leaf cells, which possessed a well developed thylakoid system, small starch grains and large plastoglobuli.

Ultrastructural localization of glutathione in Cucurbita pepo plants.

Electronmicroscopic immunogold cytochemistry was used to investigate the cellular and subcellular distribution of glutathione in root and leaf cells of Styrian pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) plants. Gold particles bound to glutathione were found in various cell structures. Statistical evaluation of the gold particle density was made for different cell compartments including nuclei, mitochondria, plastids, peroxisomes, and the cytosol. In each cell type the highest level of glutathione immunoreactivity occurred in mitochondria, for which the labeling density was found to be higher in mesophyll cells of the youngest fully developed leaves (younger leaves) than in the 5th leaves (older leaves) or in root tip cells. Additionally, a statistically significant increase of gold particles bound to glutathione was observed in nuclei (22%) and the cytosol (14%) of the root cells in comparison with mesophyll cells of older (17% and 9%, respectively) and younger leaves (11% and 6%, respectively). The relevance and specificity of glutathione labeling is discussed with respect to difficulties of immunolocalization of low-molecular-weight compounds.

The distribution and propagation of Zucchini yellow mosaic virus (ZYMV) within Styrian pumpkin plants

The distribution and propagation of Zucchini yellow mosaic virus (ZYMV) within Styrian pumpkin plants (Cucurbita pepo L. subsp. pepo var. styriaca GREB.) was studied for one week starting 6 hours after ZYMV-inoculation using transmission electron microscopy (TEM). By negative staining, virus particles were found within the cotyledons and its petioles four days after the inoculation and within the whole plant seven days after the infection. Two weeks after ZYMV-inoculation the cytoplasm of infected leaf and stem cells showed typical features of ZYMV like cylindrical inclusions and proliferated endoplasmatic reticulum. No ZYMV-induced modifications were found within root cells.

Cytological modifications in zucchini yellow mosaic virus (ZYMV)-infected Styrian pumpkin plants.

The present research demonstrates severe ultrastructural changes induced by zucchini yellow mosaic virus (ZYMV) within the cells of older and younger leaves of Styrian pumpkin plants (Cucurbita pepo L. subsp. pepo var. styriaca GREB.). Cylindrical inclusions (pinwheels), proliferated endoplasmatic reticulum and filamentous viral particles were found throughout the cytoplasm of ZYMV-infected cells and within sieve elements. ZYMV-infection also induced severe modifications in the number and ultrastructure of chloroplasts, whereas mitochondria, nuclei and peroxisomes remained unaffected. A significantly lower number of chloroplasts was observed in all tissues of both ZYMV-infected leaf types when compared to control plants. Statistical quantification revealed that in chloroplasts of ZYMV-infected older and younger leaves the amount of plastoglobuli and starch increased significantly, whereas the amount of thylakoids significantly decreased. The present research gives a more precise insight in ZYMV-induced modifications within single cells and organelles, and provides statistical data of the most affected chloroplasts.

An improved method to discover adulteration of Styrian pumpkin seed oil

Pumpkin seed oil is rather expensive compared to other vegetable oils. Therefore, it is often adulterated by the addition of cheaper oils. In contrast to other edible oils, the content of Δ5-sterols is very low, while Δ7-sterols are dominating. The determination of Δ5-sterols, especially β-sitosterol has proven to be a good possibility to detect admixture of cheap vegetable oils to a level below which the economic profit is not significant any more. The presented method is a variant of an analysis concept, which has been published previously in European Food Research and Technology by Mandl et al. [Eur. Food Res. Technol. 209 (1999) 400. ]. It includes saponification of the triglycerides as a first step followed by separation of the potassium salts of the fatty acids from the unsaponifiable fraction by adsorption chromatography. In order to enhance gas chromatographic properties of the analytes, the hydroxyl function of the sterols is derivatized with N-Methyl- N-(trimethylsilyl)trifluoroacetamide (MSTFA) to the trimethylsilylether. Finally, the analytes are separated on a capillary column of medium polarity (HP 35 MS) in a temperature programmed run within 18 min. Detection of the analytes was done by flame ionization. Special attention was set onto the precision and repeatability of the method.