Special Issue "Foodomics 2009"

Abstract: Few EU countries meet targets for saturated fatty acid (SFA) intake. Dairy products usually represent the single largest source of SFA, yet evidence indicates that milk has cardioprotective properties. Options for replacing some of the SFA in milk fat with cis-monounsaturated fatty acids (MUFA) through alteration of the cow’s diet are examined. Also, few people achieve minimum recommended intakes (~450–500 mg/d) of the long chain n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Enrichment of EPA+DHA in poultry meat via bird nutrition is described and how this would impact on habitual intake is discussed.

Abstract: Metabonomics is a well established analytical approach for the analysis of physiological regulatory processes via the metabolic profiling of biofluids and tissues in living organisms. Its potential is fully exploited in the field of “nutrimetabonomics” that aims at assessing the metabolic effects of active ingredients and foods in individuals. Yet, one of the greatest challenges in nutrition research is to decipher the critical interactions between mammalian organisms and environmental factors, including the gut microbiota. “Nutrimetabonomics” is today foreseen as a powerful approach for future nutritional programs tailored at health maintenance and disease prevention.

Abstract: Rabbit meat is a highly digestible, tasty, low-calorie food, often recommended by nutritionists over other meats. Currently research in the rabbit sector is interested in developing feeding strategies aiming to further increase the nutritional value of rabbit meat as a “functional food” by including n-3 polyunsaturated fatty acids (n-3 PUFA), conjugated linoleic acid (CLA), vitamins and antioxidants in rabbit diets and assessing their effects on both raw and stored/processed meat quality properties. Our recent studies indicate that the dietary inclusion from 3 to 6% of linseed might be considered as a way to achieve the enrichment of the meat with α-linolenic acid and to guarantee satisfactory product stability during further processing and storage. Considering that 6% dietary linseed corresponds to a n-3 PUFA content of 8.5% of the total fatty acids and a lipid content of 4.7 g/100 g of leg meat, a content of 396 mg n-3 PUFA/100g meat can be estimated, which represents about 19% of the recommended daily allowance (RDA) for n-3 PUFA.

Abstract: Fruit consumption is encouraged for health reasons; however, fruits may harbour a series of allergenic proteins that may cause discomfort or even represent serious threats to certain individuals. Thus, the identification and characterization of allergens in fruits requires novel approaches involving genomic and proteomic tools. Since avoidance of fruits also negatively affects the quality of patients’ lives, biotechnological interventions are ongoing to produce low allergenic fruits by down regulating specific genes. In this respect, the control of proteins associated with allergenicity could be achieved by fine tuning the spatial and temporal expression of the relevant genes.

Abstract: Polyunsaturated fatty acids affect gene expression mainly through peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element binding proteins (SREBPs), but how monounsaturated fatty acids affect gene expression is poorly understood. In HepG2 cells, oleate supplementation has been shown to increase secretion of hepatic lipase (HL). We hypothesized that oleate affects HL gene expression at the transcriptional level. To test this, we studied the effect of oleate on HL promoter activity using HepG2 cells and the proximal HL promoter region (700 bp). Oleate increased HL expression and promoter activity 1.3–2.1 fold and reduced SREBP activity by 50%. Downregulation of SREBP activity by incubation with cholesterol+25-hydroxycholesterol had no effect on HL promoter activity. Overexpression of SREBP2, but not SREBP1, reduced HL promoter activity, which was effected mainly through the USF1 binding site at -307/-312. Oleate increased the nuclear abundance of USF1 protein 2.7 ± 0.6 fold, while USF1 levels were reduced by SREBP2 overexpression. We conclude that oleate increases HL gene expression via USF1. USF1 may be an additional fatty acid sensor in liver cells.

Abstract: With SGF Profiling™ we introduce an NMR-based screening method for the quality control of fruit juices. This method has been developed in a joint effort by Bruker BioSpin GmbH and SGF International e.V. The system is fully automated with respect to sample transfer, measurement, data analysis and reporting and is set up on an Avance 400 MHz flow-injection NMR spectrometer. For each fruit juice a multitude of parameters related to quality and authenticity are evaluated simultaneously from a single data set acquired within a few minutes. This multimarker/multi-aspect NMR screening approach features low cost-per-sample and is highly competitive with conventional and targeted fruit juice quality control methods.

Abstract: Red microalgae contain functional sulfated polysaccharides (containing dietary fibers), polyunsaturated fatty acids, zeaxanthin, vitamins, minerals, and proteins. Studies in rat models support the therapeutic properties of algal biomass and isolated polysaccharides. Algal products incorporated into rat diets were found to significantly improve total serum cholesterol, serum triglycerides, hepatic cholesterol levels, HDL/LDL ratios and increased fecal excretion of neutral sterols and bile acids. Morphological and metabolic changes were induced by consumption of algal products. These results suggest that red microalgae can be used as potent hypocholesterolemic agents, and they support the potential use of red microalgae as novel nutraceuticals.

Abstract: Seed and fruit development are intimately related processes controlled by internal signals and environmental cues. The absence of seeds is usually appreciated by consumers and producers because it increases fruit quality and fruit shelf-life. One method to produce seedless fruit is to develop plants able to produce fruits independently from pollination and fertilization of the ovules. The onset of fruit growth is under the control of phytohormones. Recent genomic studies have greatly contributed to elucidate the role of phytohormones in regulating fruit initiation, providing at the same time genetic methods for introducing seedlessness in horticultural plants.

Abstract: Lactobacillus sakei is widely used as starter in the production process of Italian fermented sausages and its growth and survival are affected by various factors. We studied the differential expression of genome in response to different stresses by the fluorescent differential display (FDD) technique. This study resulted in the development and optimization of an innovative technique, with a high level of reproducibility and quality, which allows the identification of gene expression changes associated with different microbial behaviours under different growth conditions.

Abstract: Milk and dairy products are an essential food and an economic resource in many countries. Milk component synthesis and secretion by the mammary gland involve expression of a large number of genes whose nutritional regulation remains poorly defined. The purpose of this study was to gain an understanding of the genomic influence on milk quality and synthesis by comparing two sheep breeds with different milking attitude (Sarda and Gentile di Puglia) using sheep-specific microarray technology. From sheep ESTs deposited at NCBI, we have generated the first annotated microarray developed for sheep with a coverage of most of the genome.

Abstract: The use of molecular marker in the dairy sector is gaining large acceptance as a reliable diagnostic approach for food authenticity and traceability. Using a PCR approach, the rbcL marker, a chloroplast-based gene, was selected to amplify plant DNA fragments in raw cow milk samples collected from stock farms or bought on the Italian market. rbcL-specific DNA fragments could be found in total milk, as well as in the skimmed and the cream fractions. When the PCR amplified fragments were sent to sequence, the nucleotide composition of the chromatogram reflected the multiple contents of the polyphytic diet.

Abstract: The immunogenic potential of α-gliadin protein from two ancient wheats was studied with reference to coeliac disease. To this aim we investigated Graziella Ra® and Kamut® (the latter is considered an ancient relative of modern durum wheat) in comparison to four durum wheat accessions (Senatore Cappelli, Flaminio, Grazia and Svevo). ELISA and Western Blot analyses - carried out by two monoclonal antibodies raised against the α-gliadin peptides p31-49 (LGQQQPFPQQPYPQPQPF) and p56-75 (LQLQPFPQPQLPYPQPQLPY) containing a core region (underlined) reported to be toxic for coeliac patients - always showed an antibody-antigen positive reaction. For all accessions, an α-gliadin gene has also been cloned and sequenced. Deduced amino acid sequences constantly showed the toxic motifs. In conclusion, we strongly recommend that coeliac patients should avoid consuming Graziella Ra® or Kamut®. In fact their α-gliadin not only is as toxic as one of the other wheat accessions, but also occurs in greater amount, which is in line with the higher level of proteins in ancient wheats when compared to modern varieties.

Abstract: Identification of proteins involved in milk production is important to understand the biology of lactation. Many studies have advanced the understanding of mammary function and milk secretion, but the critical molecular mechanisms implicated in milk fat secretion is still incomplete. Milk Fat Globules are secreted from the apical surface of the mammary cells, surrounded by a thin membrane bilayer, the Milk Fat Globule Membrane (MFGM), formed by proteins which have been suggested to be cholesterolemia-lowering factors, inhibitors of cancer cell growth, vitamin binders, bactericidal, suppressors of multiple sclerosis. Using a proteomic approach, we compared MFGM from milk samples of individuals belonging to two different cattle breeds, Chianina and Holstein, representative of selection for milk and meat traits, respectively. We were able to isolate some of the major MFGM proteins in the examined samples and to identify differences between the protein fractions of the two breeds. We detected differences in the amount of proteins linked to mammary gland development and lipid droplets formation, as well as host defence mechanisms. We have shown that proteomics is a suitable, unbiased method for the study of milk fractions proteins and a powerful tool in nutritional genomics.

Abstract: Food product authentication provides a means of monitoring and identifying products for consumer protection and regulatory compliance. There is a scarcity of analytical methods for confirming the identity of fruit pulp in products containing Soft Fruit. In the present work we have developed a very sensible qualitative and quantitative method to determine the presence of berry DNAs in different food matrices. To our knowledge, this is the first study that shows the applicability, to Soft Fruit traceability, of melting curve analysis and multiplexed fluorescent probes, in a Real-Time PCR platform. This methodology aims to protect the consumer from label misrepresentation.

Abstract: The ¹H-NMR methodology used in the study of genetically modified (GM) foods is discussed. Transgenic lettuce (Lactuca sativa cv \"Luxor\") over-expressing the Arabidopsis KNAT1 gene is presented as a case study. Twenty-two water-soluble metabolites (amino acids, organic acids, sugars) present in leaves of conventional and GM lettuce were monitored by NMR and quantified at two developmental stages. The NMR spectra did not reveal any difference in metabolite composition between the GM lettuce and the wild type counterpart. Statistical analyses of metabolite variables highlighted metabolism variation as a function of leaf development as well as the transgene. A main effect of the transgene was in altering sugar metabolism.

Abstract: The prevalence of Celiac Disease (CD), an autoimmune enteropathy, characterized by chronic inflammation of the intestinal mucosa, atrophy of intestinal villi and several clinical manifestations has increased in recent years. Subjects affected by CD cannot tolerate gluten protein, a mixture of storage proteins contained in several cereals (wheat, rye, barley and derivatives). Gluten free-diet remains the cornerstone treatment for celiac patients. Therefore the absence of gluten in natural and processed foods represents a key aspect of food safety of the gluten-free diet. A promising area is the use of minor or pseudo-cereals such as amaranth, buckwheat, quinoa, sorghum and teff. The paper is focused on the new definition of gluten-free products in food label, the nutritional properties of the gluten-free cereals and their use to prevent nutritional deficiencies of celiac subjects.

Abstract: Berries contain significant amounts of phytochemicals, including polyphenols, which are reported to reduce cancer risk, coronary heart disease and other degenerative diseases. These effects are mainly attributed to the antioxidant capacity of polyphenols found in berries. Strawberry tree (Arbutus unedo) berries are used in folk medicine but seldom eaten as fresh fruits. Their phenolic profile and antioxidant capacity reveal a high potential, but they are not well characterized as a “health promoting food”. The aim of this study was to assess the antioxidant properties of the edible strawberry tree fruit in vitro and in a neurodegeneration cell model. Raspberry (Rubus idaeus), a well documented health-promoting fruit, was used as a control for comparison purposes. A. unedo yielded a similar content in polyphenols and a slightly lower value of total antioxidant capacity in comparison to R. idaeus. Although the chemically-measured antioxidant activity was similar between both fruits, R. idaeus increased neuroblastoma survival in a neurodegeneration cell model by 36.6% whereas A. unedo extracts caused no effect on neuroblastoma viability. These results clearly demonstrate that a promising level of chemically-determined antioxidant activity of a plant extract is not necessarily correlated with biological significance, as assessed by the effect of A. unedo fruit in a neurodegeneration cell model.

Abstract: 1H NMR spectra were recorded of methanolic extracts of seven soybean varieties (Glycine max.), cultivated using traditional and organic farming techniques. It was possible to identify signals belonging to the groups of amino acids, carbohydrates, organic acids and aromatic substances in the spectra. In the aromatic zone, the isoflavone signals were of particular interest: genistein, daidzein, genistin, daidzin, malonylgenistin, acetylgenistin, malonyldaidzin signals were assigned and these compounds were quantified, resulting in accordance with published data, and further demonstrating the potential of the NMR technique in food science.

Abstract: Post-translational modifications of chromatin contribute to the epigenetic control of gene transcription. The response to food intake and individual nutrients also includes epigenetic events. Bile acids are necessary for lipid digestion and absorption, and more recently have emerged as signaling molecules. Their synthesis is transcriptionally regulated also in relation to the fasted-to-fed cycle, and interestingly, the underlying mechanisms include chromatin remodeling at promoters of key genes involved in their metabolism. Several compounds present in nutrients affect gene transcription through epigenetic mechanisms and recent studies demonstrate that, beyond the well known anti-cancer properties, they beneficially affect energy metabolism.

Abstract: The molecular profiles of perchloric acid solutions extracted from the flesh of Sparus aurata fish specimens, produced according to different aquaculture systems, have been investigated. The ¹H-NMR spectra of aqueous extracts are indicative of differences in the metabolite content of fish reared under different conditions that are already distinguishable at their capture, and substantially maintain the same differences in their molecular profiles after sixteen days of storage under ice. The fish metabolic profiles are studied by top-down chemometric analysis. The results of this exploratory investigation show that the fish metabolome accurately reflects the rearing conditions. The level of many metabolites co-vary with the rearing conditions and a few metabolites are quantified including glycogen (stress indicator), histidine, alanine and glycine which all display significant changes dependent on the aquaculture system and on the storage times.