Computational estimation of soybean oil adulteration in Nepalese mustard seed oil based on fatty acid composition

The experiment was carried out for the computational estimation of soybean oil adulteration in the mustard seed oil using chemometric technique based on fatty acid composition. Principal component analysis and K-mean clustering of fatty acid composition data showed 4 major mustard/rapeseed clusters, two of high erucic and two of low erucic mustard type. Soybean and other possible adulterants made a distinct cluster from them. The methodology for estimation of soybean oil adulteration was developed based on weighted least square error principle using Microsoft Excel Solver program. This principle was successfully validated on the real soybean mustard oil blends. Moreover, the method was further evaluated on the 4000 training set and 3999 validation set simulated blends of mustard and soybean oil based on 212 fatty acid composition data. The blending was simulated with data from different literature from different part of the world along with data collected in our laboratory. The simulated blend consisted of random mixture of up to 16 samples. These are more extreme conditions than that can usually be expected in real scenario

Influence of oxidized oils on digestibility of caseins in O/W emulsions

The impact of lipid oxidation on protein modifications in emulsions and the consequences on protein digestibility remains unclear. In this study, this impact is evaluated in casein (6 mg mL(-1)) based emulsions containing oxidized soybean or fish oil (3%) in presence (0.3%) or absence of the emulsifier Tween 20. Emulsions are prepared using oils at three oxidation levels and subsequently the impact on protein digestibility is evaluated after 24 h incubation at 4 degrees C. Remarkably, protein digestibility increases in emulsions containing medium and highly oxidized fish oil: 70 +/- 0.4% and 73 +/- 0.4% of the proteins are digested, respectively, whereas protein digestibility in emulsions containing low oxidized fish oil amounted to 63 +/- 0.4%. Protein digestibility in emulsions containing soybean oil stabilized by Tween 20 is not influenced by the oxidation level of the oil used. A remarkable tendency is observed for the malondialdehyde content of the emulsions depending on the presence of Tween 20. For soybean oil based emulsions, malondialdehyde concentrations are consistently higher in the presence of Tween 20. On the other hand, for the fish oil based emulsions an opposite trend is observed, except at the highest oxidation level evaluated, for which no significant differences can be detected. It is concluded that the composition of the interface in emulsions depends strongly upon the degree of oil oxidation and the presence of other emulsifiers. If the oil is more oxidized, less protein is present in the interface restricting the impact of lipid oxidation products on the proteins and hence their digestibility

Development of a new hazelnut sandwich ELISA based on detection of Cor a 9, a major hazelnut allergen

The emerging health problem of food-induced allergic reactions, including life-threatening anaphylaxis, presents an important challenge to the food. In the framework of the current ALLERRISK project, analytical approaches for allergen detection are evaluated and developed. Cor a 9 is a major hazelnut protein with nutrient reservoir function, and that also known as a major food allergen. Presence of Cor a 9 indicates contamination of a product with hazelnut and, consequently, potential risk of allergenicity. Crude extract of hazelnut was obtained from milled mixture of hazelnuts from 10 commercially available brands. Then the extract was concentrated and applied to gel filtration and Con A affinity chromatography columns for Cor a 9 isolation and purification. The final product was characterized by analytical gel permeation chromatography, SDS PAGE and MALDI mass spectrometry. The purified Cor a 9 was used as an antigen for the production of polyclonal antibodies in chickens according to the protocol developed in our laboratory. A part of the most active antibodies was further purified by gel permeation chromatography and characterized by SDS PAGE before further use. The prepared antibodies were applied for development of a sandwich ELISA using polyclonal antibody-enzyme adducts as a tracer. Optimization of reagent concentrations led us to achieve detection limit ~10 ng/ml. Influence of ionic strength, pH and buffer composition on analytical parameters of the developed ELISA were thoroughly studied. The developed ELISA can be successfully applied for quantitative detection of Cor a 9 in large pH (pH = 5 – 10) and ionic strength (0.05 – 1.5 M salts solution) ranges. Cross-reactivity with series of nuts, ovalbumin, whey, and wheat proteins was also investigated (Figure 2) and showed that the developed assay was very specific. Moreover, presence of several other proteins (peanut, cashew, ovalbumin, whey and wheat) at high concentrations (1 mg/ml) in the presence of Cor a 9 did not influence the calibration curve of Cor a 9. Detection of hazelnut protein in cookies with known amount of hazelnut inside initial dough showed good recovery (35-40%) and absence of significant signal in blank samples (i.e. without spiking of hazelnut)

MAP as a conservation method for contemporary art with foodstuffs : three case studies

This article examines the use of Modified Atmosphere Packaging (MAP), a widely applied preservation method in the food packing industry, for preserving contemporary artworks with foodstuffs. Three case studies are presented for which guidelines to preserve those works are proposed, taking into account the temporal, ephemeral character of these artworks on the one hand and their material preservation on the other hand and to explore whether and how they can be presented and preserved for future generations

Integrated risk assessment of selected mycotoxins in fresh produce and derived food products throughout the food chain, affected by climate changes and globalization

Fruits and vegetables are an important part of a healthy diet, and their consumption is expected to increase in the future because of health promotion. However, climate change and globalization will have an effect on their food safety (Paterson & Lima 2010). In order to maintain the desired level of food safety in Europe, it is necessary to explore new food contamination pathways and approaches to deal with these projected changes. An imported food safety problem is the presence of fungi and mycotoxins. (Semi) dried plants are mainly associated with mycotoxins but recently fresh produce are associated with new emerging mycotoxins. The objective of the research is to develop a farm-to-fork risk assessment model to predict the mycotoxin concentration in fresh and derived products in order to predict future risks due to climate change and growing import of foods from third countries. An initial inventory is made of relevant moulds and mycotoxins present on fresh produce and derived food products. Therefore data of mycotoxin concentration on dried plant, fresh and derived products are collected. This is done in cooperation with ICPC partners (e.g. Egypt, Brazil, Serbia and India) and is extended with European and national data. The data are obtained by including both scientific articles and grey literature (e.g. EFSA, RASFF). Most data are found from dried products, such as nuts, dried fruits and spices and herbs. Almost no data is available on fresh produce. To collect additional information (on fresh produce and derived products) a screening method with LC-TOF-MS is running for ochratoxin A, fumonisin B1, B2, B3, alternariol and alternariol monomethyl ether in tomatoes, onions, sweet bell peppers and soft red fruits. The MS parameters were tuned for each mycotoxin and both positive and negative electrospray conditions were checked. It was decided to screen for the mycotoxins in two separated runs (positive and negative electrospray run). The six mycotoxins can be screened in one sample in a relative short time of one hour. To screen for patulin we performed an non quantitative method with an HPLC with an extraction method described by Sanzani et al. (Sanzani et al. 2009). Preliminary results showed a presence of 14% of patulin in mouldy tomatoes (15 out of 107)

Whey proteins interact with lipids during autoxidation primarly via the production of reactive carbonyl species

Nowadays, it is well recognized that polyunsaturated fatty acids (PUFAs) can provide extensive nutritional and health benefits. Thus, ω-3 PUFAs have been considered to contribute to the prevention of several diseases. Recognition of the potential benefits of ω-3 fatty acids has stimulated increased interest towards the fortification of foods with oils rich in these particular fatty acids. However, enrichment of food products with such unsaturated fatty acids should be carefully evaluated since they are highly susceptible to oxidation. Moreover, exposure of proteins to peroxidizing lipids or their secondary breakdown products may induce severe changes in proteins, including polymerization, insolubilization and formation of lipid – protein complexes. Several amino acids, but mainly mainly cysteine, methionine, histidine, tyrosine and lysine are affected by the secondary lipid oxidation products, therefore leading to reductions of their availability. The objective of this study was to characterize changes induced in whey protein isolate (a mixture of α-lactalbumin and β-lactoglobulin) through oxidation with oils with different unsaturation degrees and different initial oxidation status. The incubation of whey proteins with oils caused an increase in protein bound carbonyl content through the interaction of lipid oxidation products with the amino acids. Changes in the amino acid composition were therefore also observed mostly upon incubation with fish and highly oxidized soybean oil. Interaction of proteins with lipid oxidation products was taking place via interaction of the reactive carbonyl species formed thus leading to protein aggregates formation. Protein aggregation was therefore one of the most prominent consequence of the interaction of whey proteins with oxidizing lipids

Stability of whey protein derived peptides upon severe protein glycation

Cow’s milk and dairy products are major nutrients in the human diet, especially during infancy. Though at one time whey proteins were considered as by-product of the cheese making process, nowadays, due to their wide ranging nutritional, biological, and functional properties, whey proteins are often used in food technology as low-cost protein ingredients. However, whey-protein fractions, such as β-lactoglobulin (β-LG) and α-lactalbumin (α-LA) represent the major allergens in cow’s milk. Therefore, the use of whey proteins in food might pose a serious threat to the milk allergic consumers. It is well reported that food processing may modify the allergenicity and detectability of proteins. This can be due to hydrolysis or chemical reactions with other food components (carbohydrates, fatty acids etc), leading to modification or destruction of the allergen’s structure. Therefore, the objective of this study was in the first stage to investigate the influence of glycation on the molecular changes induced in whey proteins. This was done with a special focus on the modifications induced on the lysine residues, free amino groups, the formation of protein bound carbonyls, formation of fluorescent compounds and brown polymers and on the protein aggregation. Matrix-assisted laser desorption/ionization - time of flight mass spectrometry (MALDI-TOF MS) was used to get a better insight into the molecular changes that took place on the protein level. Unexpectedly, this study led to the identification of protein segments in the epitope region that remained unmodified during the experiments that mimic typical food processing conditions. The 57Val – Lys76 and 31Val – Arg56 from β–LG, remained unchanged disregarding the severe heating treatment in the presence of glucose and bulk proteins and they could be identified by either direct MALDI-TOF MS and MS/MS or after a more tedious separation using reversed phase chromatography. It is proposed that these peptide segments can be used as analytical targets for the development of more robust methods for the assessment of the presence of whey proteins in processed foodstuffs. Moreover, MALDI-TOF MS and MS/MS holds potential to be used as a screening tool for the identification of such stable peptides