January 2011 - OurFood-news

31.01.2011: Sequencing genes which express cellulose degrading enzymes of bacteria [1]
Fermenting cellulosic plant material may replace the fermentation of food crops such as corn, beets or sugar cane. This technology competes with food crops and is expensive.
Hess and colleagues 2011 studied the enzymes which can convert cellulosic biomass in biofuels. The authors defined and sequenced the biomass-degrading genes of bacteria living in the rumen of cows. These bacteria digest cellulose, but are difficult to cultivate. The data provided by the authors increase the understanding of genes engaged in cellulose biomass degradation and may helps to develop strains which produce biofuels from non-food plant material.

Consolidated bioprocessing producing volatile fatty acids and methane as fuel [2]
Hemme and colleagues 2011 describe the consolidated bioprocessing (CBP) of cellulosic biomass for the production of bioethanol. It uses anaerobic bacteria in a single reactor. To turn this system feasible, the authors propose to explore further the data of studies on ruminant fermentation. which produces low ethanol but yields high amount of volatile fatty acids and methane. The authors propose to use these compounds as fuel.

Clostridial genome may help understanding of biofuel production from cellulose [3]
Clostridium species may convert biomass conversion into biofuels and industrial products. To increase knowledge of these bacteria Hemme and colleagues 2010 sequenced the genomes of 20 species, the majority of which were of the class III cellulosome-encoding Clostridium and the class V saccharolytic Thermoanaerobacteraceae. Data reported by the authors may be useful for future studies on biofuels, cellulosome composition, and biology of Clostridial spp. Cellulosomes are complexes of cellulolytic enzymes created by bacteria such as Clostridium and Bacteroides.

Contribution of synthetic biology to biofuels of second generation [4]
Jarboe and colleagues 2010 reviewed the traditional metabolic engineering of enzymes generating genes in the production of biofuels from cellulosic materials. The authors stress the importance of synthetic biology in biocatalyst engineering for fuels and chemicals production, such as ethanol, butanol, acetate, lactate, succinate, alanine, and xylitol.

Engineering non-cellulolytic bacteria to become cellulose fermenter [5]
Lignocellulosic biomass is an abundant feedstock for biofuels, however enzymes that ferment the cellulose and hemicelluloses to ethanol in one step are needed to reduce the costs of the process which is still being done in various reactors by different organisms. According to la Grange and colleagues 2010, researchers are trying to turn normal bacteria more efficient, or engineer non-cellulolytic bacteria to express cellulolytic enzymes to be integrated in a consolidated bioprocess (CBP).

Biocommodity, a new fiel of biotechnology [6]
Lynd, Wyman and Gerngross 2010 describe "biocommodity engineering" as a new field of biotechnology. It is driven by economic interests, by the availability of feedstocks, by cost reductions, and different applications. Thus it differs from the motivation of biotechnology used to produce health care products.
Researcher are trying to reduce the costs biocommodity engineering applying "consolidated bioprocessing" in which cellulase production, cellulose hydrolysis, and fermentation of soluble carbohydrates to desired products are included in a single process step.

To achieve this goal, desired pathways are engineered into an organism which already has good industrial properties. Such organism has to be identified and modified accordingly using biocommodity engineering. The future biocomodity engineering will depend on the coproduction of fuels, chemicals, power, and feed in one system. Lifecycle analysis must be applied to turn the process sustainable. The authors suggest to create a biocommodity engineering graduate study based on biotechnology, process engineering, and resource and environmental systems.

Metabolic engineering increases process efficiency of bioproducts [7]
Metabolic engineering develop strains which synthesise chemicals and materials from renewable sources using synthetic biology. Such engineering of microorganisms enhances their productivity of normal chemicals or produce new compounds. Na, Kim and Lee 2010 review such new constructed synthetic pathways used to produce non-innate chemicals.

Escherichia coli and metabolic engineering  [8]
Using advanced metabolic engineering and synthetic biology Escherichia coli is being engineered to produce biofuels from different biomass feedstocks. Clomburg and Gonzales 2010 highlight the capability of this bacterium to utilise a variety of substrates and synthesise various biofuels, such as alcohols and higher carbon biofuels derived from fatty acid and isoprenoid pathways.

Tools of systemic biology in industrial biotechnology [9]
Otero and Nielsen 2010 affirm that metabolic engineering may insert new enzymes activities or silence existing enzyme activities. However, this may deregulate important cell regulatory pathways. Careful genetic modification is therefore necessary. To avoid unwanted reactions, tools from systemic biology, such as x-ome technologies (transcriptome, proteome, metabolome, and fluxome analysis), and mathematical modeling tools (genome-scale metabolic modeling) are increasingly being used.

[1] Hess M, Sczyrba A, Egan R, Kim TW, Chokhawala H, Schroth G, Luo S, Clark DS, Chen F, Zhang T, Mackie RI, Pennacchio LA, Tringe SG, Visel A, Woyke T, Wang Z, Rubin EM: Metagenomic Discovery of Biomass-Degrading Genes and Genomes from Cow Rumen. Science. 2011 Jan 28;331(6016):463-467.
http://www.ncbi.nlm.nih.gov/pubmed/21273488

[2] Weimer PJ, Russell JB, Muck RE: Lessons from the cow: what the ruminant animal can teach us about consolidated bioprocessing of cellulosic biomass. Bioresour Technol. 2009 Nov;100(21):5323-31.
http://www.ncbi.nlm.nih.gov/pubmed/19560344

[3] Hemme CL et al.: Sequencing of multiple clostridial genomes related to biomass conversion and biofuel production. J Bacteriol. 2010 Dec;192(24):6494-6.
http://www.ncbi.nlm.nih.gov/pubmed/20889752

[4] Jarboe LR, Zhang X, Wang X, Moore JC, Shanmugam KT, Ingram LO: Metabolic engineering for production of biorenewable fuels and chemicals: contributions of synthetic biology. J Biomed Biotechnol. 2010;2010:761042.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2857869/?tool=pubmed

[5] la Grange DC, den Haan R, van Zyl WH: Engineering cellulolytic ability into bioprocessing organisms.
http://www.ncbi.nlm.nih.gov/pubmed/20508932

[6] Lynd LR, Wyman CE, Gerngross TU: Biocommodity Engineering. Biotechnol Prog. 1999 Oct 1;15(5):777-793. Appl Microbiol Biotechnol. 2010 Jul;87(4):1195-208.
http://www.ncbi.nlm.nih.gov/pubmed/10514248

[7] Na D, Kim TY, Lee SY: Construction and optimization of synthetic pathways in metabolic engineering. Curr Opin Microbiol. 2010 Jun;13(3):363-70.
http://www.ncbi.nlm.nih.gov/pubmed/20219419

[8] Clomburg JM, Gonzalez R: Biofuel production in Escherichia coli: the role of metabolic engineering and synthetic biology. Appl Microbiol Biotechnol. 2010 Mar;86(2):419-34.
http://www.ncbi.nlm.nih.gov/pubmed/20143230

[9] Otero JM, Nielsen J: Industrial systems biology: Biotechnol Bioeng. 2010 Feb 15;105(3):439-60.
http://www.ncbi.nlm.nih.gov/pubmed/19891008


29.01.2011: Antioxidants implicated in reduced women fertility [1]
A study of Shkolnik and colleagues 2011 stresses that ovulation is stimulated the pituitary luteinizing hormone (LH). This process is related to inflammation involving oxidant radicals (reactive oxygen species ROS). In their study the authors found that antioxidants reduced the rate of ovulation in rats preventing the modification of the local tissue, which prepares the ovulation.

Progesterone production was also found to be reduced by antioxidants, together with up-regulation of genes by the LH hormone which were also significantly reduced. Oxidants on their turn, were found to be implicated in phosphorylation and activation of the epidermal growth factor receptor (EGFR) and its downstream effector, p42/44 MAPK, essential elements of ovulation. More studies related to antioxidants supplements and its possible implication in reduction of fertility are needed.

The authors concluded that the production of ovary oxidant radicals is essential to fertility and antioxidants may become a non-hormonal contraceptive.

[1] Shkolnik K, Tadmor A, Ben-Dor S, Nevo N, Galiani D, Dekel N. Reactive oxygen species are indispensable in ovulation. Proc Natl Acad Sci U S A. 2011 Jan 25;108(4):1462-7.
http://www.pnas.org/content/108/4/1462.long


29.01.2011: Dietary polyamines [1]
Polyamines, such as putrescine, spermine, and spermidine, are synthesized endogenously from ornithine with the enzymes ornithine decarboxylase and S-adenosylmethionine decarboxylase. Other source is food and absorption from the products of bacterial metabolism. Polyamines play an important role in regulating cell growth and proliferation. If cellular polyamine synthesis is inhibited, cell growth is stopped or severely retarded. The provision of exogenous polyamines restores the growth of these cells. Most eukaryotic cells have a polyamine transporter system on their cell membrane that facilitates the internalization of exogenous polyamines. This system is highly active in rapidly proliferating cells and is the target of some chemotherapeutics currently under development.

Polyamines are also engaged in the stabilization of negative charges of DNA, RNA transcription, protein synthesis and the regulation of the immune response. Polyamines are found in breast milk and may be important in maturation of infant gut, and a possible supplementation of infant formulas with polyamines is being studied, say Larqué and colleagues 2007 .

Programmed cell death (apoptosis) include the activation of endogenous calcium and magnesium dependent endonucleases, leading to fragmentation of the chromosomal DNA which is destabilized in polyamine-depleted cells. [2]

Swedish Food Database contains selected data on polyamine [3]
The Swedish Food Database contains data on polyamine content of selected Swedish dairy products. According to Ali and colleagues 2011, these data suggest that fruits and cheese have the highest content of putrescine. Vegetables and meat products were high in spermidine and spermine, respectively. Highest levels of total polyamides were found in Swedish matured cheese, namely 52.3, 1.2, and 2.6 mg/kg for putrescine, spermidine, and spermine, respectively. Low fat milk had higher Putrescine and spermidine, 1.2 and 1.0 mg/kg, respectively, compared with other types of milk.

The authors calculated the polyamine intake from food in adolescents using the database, and compared these results to a diet fulfilling the Swedish Nutrition Recommendations (SNO). The mean daily polyamine intake was found to be 316±170 µmol/day, and 541 µmol/day calculated according to SNO. Almost half of the polyamide intake came from fruits The difference between both results was caused by low vegetable intake by the adolescents. This was found by the authors to have caused the difference between both results. The authors stress that the “ideal” diet according to Swedish nutrition recommendations presents higher results for polyamide than achieved Sweden and reported in Europe. [4]

[1] Larqué E, Sabater-Molina M, Zamora S: Biological significance of dietary polyamines. Nutrition. 2007 Jan;23(1):87-95.
http://www.ncbi.nlm.nih.gov/pubmed/17113752


[2] Cell Proliferation Group: The role of the polyamines in cell cycle control and programmed cell death.Lund University.2011.
http://www.djur.cob.lu.se/Cellprolif/Research/research_area_1.html


[3] Ali MA, Poortvliet E, Strömberg R, Yngve A: Polyamines in foods: development of a food database. Food Nutr Res. 2011 Jan 14;55. doi: 10.3402/fnr.v55i0.5572.
http://www.ncbi.nlm.nih.gov/pubmed/21249159

[4] Ali MA, Poortvliet E, Strömberg R, Yngve A: Polyamines: total daily intake in adolescents compared to the intake estimated from the Swedish Nutrition Recommendations Objectified (SNO). Food Nutr Res. 2011 Jan 14;55. doi: 10.3402/fnr.v55i0.5455.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3022765/?tool=pubmed


28.01.2011: Breakfast
Breakfast is the most important meal of the day. Researches on the effect on cognitive function, health and obesity are still unsufficient, say researchers.

Reduction of breakfast calories reduces overall daily energy intake [1]
According to Schusdziarra and colleagues 2011 increasing breakfast calories is associated with greater overall energy intake. The increasing ratio of breakfast to total daily energy intake was associated with a significant reduction of overall intake when post-breakfast energy was significantly reduced. The authors stress that breakfast calories have the strongest influence on daily energy intake. They recommend overweight and obese subjects should consider the reduction of breakfast calories to reduce their body-weight.

Daily breakfast consumers are less overweight, have improved cognitive functions and health [2]
A review by Rampersaud and colleagues 2005 stresses children which eat breakfast regularly have also a healthier dietary habits compared with breakfast-skipping children. Breakfast eaters consumed more daily calories but less overweight cases were reported. Breakfast consumption may improve memory, test grades, school attendance, health and well-being, according to some studies..
The authors strongly recommend the daily consumption of breakfast consisting of a variety of foods, especially high-fibre and nutrient-rich whole grains, fruits, and dairy products.

Breakfast improves school achievement of children with compromised nutritional status [3]
Breakfast is linked to healthier macro- and micronutrient intakes, BMI and lifestyle and improved cognitive function. Daily breakfast is therefore better than skipping it., but this is only in evidence in children with compromised nutritional status. Hoyland, Dye and Lawton 2009 say there are little studies on this matter and no studies were made with adolescents and make recommendations for future research design and policy priorities.

[1] Schusdziarra V, Hausmann M, Wittke C, Mittermeier J, Kellner M, Naumann A, Wagenpfeil S, Erdmann J: Impact of breakfast on daily energy intake - an analysis of absolute versus relative breakfast calories. Nutr J. 2011 Jan 17;10(1):5.
http://www.nutritionj.com/content/10/1/5

[2] Rampersaud GC, Pereira MA, Girard BL, Adams J, Metzl JD: Breakfast habits, nutritional status, body weight, and academic performance in children and adolescents. J Am Diet Assoc. 2005 May;105(5):743-60; quiz 761-2.
http://www.ncbi.nlm.nih.gov/pubmed/15883552

[3] Hoyland A, Dye L, Lawton CL: A systematic review of the effect of breakfast on the cognitive performance of children and adolescents. Nutr Res Rev. 2009 Dec;22(2):220-43.
http://www.ncbi.nlm.nih.gov/pubmed/19930787


27.01.2011: Nutrition and prostata cancer prevention [1]
Schmidt and colleagues 2011 point out that heredity, ethnic origin, and increasing age are risk factors of prostate cancer. Environmental factors also play an important role in the development of the disease. Men with the same genetic background, but living in different environments diseased in association with the place where they lived.

Nutritional factors: Total energy intake (as reflected by body mass index), dietary fat, cooked meat, micronutrients and vitamins (carotenoids, retinoids, vitamins C, D and E), fruit and vegetable intake, minerals (calcium, selenium), and phytoestrogens (isoflavonoids, flavonoids, lignans) were found to reduce the risk of prostate cancer.
 
However, selenium and vitamin E were found to be of no benefit to cancer prevention by The selenium and vitamin E cancer prevention trial (SELECT). Therefore the trial was discontinued Overall the authors recommend lifestyle changes to reduce the risk of prostate cancer.

[1] Schmid HP, Fischer C, Engeler DS, Bendhack ML, Schmitz-Dräger BJ: Nutritional aspects of primary prostate cancer prevention. Recent Results Cancer Res. 2011;188:101-7.
http://www.ncbi.nlm.nih.gov/pubmed/21253792


26.01.2011: Haram Food List of Dubai
Dubai Municipality’s food control department published a list of Haram foods for travellers to non-Islamic countries.

The Haram food list of Dubai Municipality’s food control department 2011
Pork
Animal fat: Animal fat from an unspecified source
Bacon: Salted pork, cut from the back or side
Bath chap: Pork from the lower cheek, on the bone
Belly: Pork cut from the underside of the animal
Brawn: Marinated pork
Bone broth: Soup containing meat of unspecified origin
Fish ham: A Japanese fish sausage made with pork fat.
Gel: Gelatinous material of unspecified source
Gammon: Smoked pork thigh
Ham: Pork thigh meat
Haslet: a herbed pork meatloaf
Lard: Pork fat
Lardine: Margarine made with pork fat
Margerine: Vegetable oil with 10 per cent added animal fat of unspecified source
Pepsin: An enzyme extracted from animal’s – especially pig’s – stomach
Pepperoni: Sausage made from unspecified meat
Rasher: A slice of bacon
Renin: An enzyme extracted from calves’ and pigs’ stomach
Saveloy: Pork frankfurters
Alcohol
Wine, Champagne, Brandy, Burgundy, Whiskey, Gin, Scotch, Beer, Rum, Bordeaux, Malt, Liqueur, Vodka, Mescal, Marc, Maraschino, Alcohol, Vin rouge, Vin blanc.


26.01.2011: High sugar and saturated fats diet increases incidence of diseases in Brazil
Change in dietary habits of Brazilian population leads to obesity and related diseases [1]
Levi-Costa and colleagues report an increasing consumption of sugar leading to excess of calories and low intake of fruits and vegetables in Brazil. A high proportion of calories from saturated fats in urban regions displace traditional foods, like rice and beans. These local dishes are being replaced by processed foods, such as cookies and soft drinks, increasing the amount of sugar and saturated fats in the Brazilian diet.

23.01.2011: Cereal aphids

The Russian wheat aphid (Diuraphis noxia) cause significant losses in cereal crops and is considered to be the most devastating pest of bread wheat, durum wheat and barley.. The saliva of this aphid is toxic to the plant and causes whitish striping on cereal leaves. Feeding by this aphid will also cause the flag leaf to turn white and curl around the head causing incomplete head emergence. Host plants are cereal grain crops including wheat and barley and to a lesser extent, wild grasses such as wheatgrasses, brome-grasses or ryegrasses.

Aphid strains [1]

The Russian wheat aphid biotype designations of seven biotypes 1-7 (RWA1-7) was confirmed by Randolph and colleagues 2009. RWA 1 was found to be the least virulent of the aphids tested. RWA 3 was highly virulent and RWA 2 was the most virulent strain of all aphids.

Aphids multiple invasion in USA [2]

Even after several aphid resistance genes had been introduced in commercial wheat and barley genotypes up to eight virulent biotypes occur across the western United States. Using genetic maping techniques Liu and colleagues 2010 found that there have been at least two Diruaphis noxia invasions of different origin into North America which resulted in postinvasion diversification giving origin to the actual biotypes.

Symbiosis between aphids and the bacterium Buchnera aphidicola [3]

Swanevelder and colleagues 2010 describe the symbiosis of the Russian wheat aphid (Diuraphis noxia) with the bacteria Buchnera aphidicola. This symbiosis turns the aphid able to feed on phloem which lacks of several essential aminoacids which are synthesized by the Buchnera aphidicola. The authors found pseudogenes, which are genes that have lost their protein-coding ability, and lower plasmid copy numbers of essential amino acid genes. The symbiosis between both species seems to degenerate. Other genetic sequences, however point to the fact that the symbiosis between Buchnera aphidicola and aphids is still valid for a variety of hosts, conclude the authors.

Oxylipin-based aphid defence mechanism of Dnx gene in wheat [4]

Smith and colleagues 2010 report that plants containing the Dnx resistance gene upregulated more than 180 genes related to reactive oxygen species, signaling, pathogen defense, and arthropod chemical and physical defense, when challenged by Russian wheat aphid (Diuraphis noxia). Based on their researches, the authors suggest that the Dnx Russian wheat aphid is regulated via the oxylipin pathway.

Greenbug Schizaphis graminum biotypes [5]

According to a study of Weng and colleagues 20101 marker data of the cereal aphid pest greenbug, Schizaphis graminum, revealed host-adapted genetic divergence as well as regional differentiation. Host associated biotypic variation was found at agricultural cultivated areas, and more geographic divergence was found in populations living on noncultivated grasses. Monitoring of greenbug biotyping variation on crop plants and noncultivated grasses may be useful to detect new virulent biotypes of the greenbug.

Host plant resistance to aphids [6]

Dogimont and colleagues 2010 report that resistant-breaking biotypes have occurred due to a limited number of aphid resistance genes and alleles in host plants.

Two aphid resistance genes encode NBS-LRR proteins involved in plant resistance to aphids.

Aphids prefer to settle on fertilised plants [7]

Aphid species (Uroleucon tanaceti and Macrosiphoniella tanacetaria) prefer to settle on plants (tansy) fertilised with ammonium nitrate. The phloem sap of these plants contained higher amino acid concentrations, without a change in the proportion of essential amino acids. The aphids presented a longer phloem feeding time on fertilised plants and also a longer stay in sieve tubes, compared with plants which were not fertilised.

Nowac and Komor 2010, authors of the study, say that aphids identified the nutritional quality of the host plant mainly by the amino acid concentration of phloem sap, not by leaf surface cues nor the proportion of essential amino acids. The authors note that Uroleucon tanaceti infestation increased the methionine plus tryptophan content in phloem significantly. This alters the nutrients of the plantmanipulating the plants nutritional quality, and causing premature leaf ageing.

No significant change in feeding behaviours of aphids living on low amino acid phloem concentration [8]

The amino acid permease gene AAP6 (At5g49630) regulates phloem amino acid composition. Abolished function of this gene in Arabidopsis thaliana produced phloem with low total amino acids and low levels of lysine, phenylalanine, leucine, and aspartic acid. However, despite these changes in diet, Myzus persicae aphids presented only small changes in feeding behaviour on this host.

AKR gene is related to resistance to aphids [9]

The authors found that resistance to bluegreen aphid (Acyrthosiphon kondoi) was related to AKR, a single dominant gene which was also found in cases of resistance to pea aphid (Acyrthosiphon pisum). Studies were performed with a clover-ike plant Medicago truncatula presenting similar transcription factor expression patterns.

[1] Randolph TL, Peairs F, Weiland A, Rudolph JB, Puterka GJ: Plant responses to seven Russian wheat aphid (Hemiptera: Aphididae) biotypes found in the United States. J Econ Entomol. 2009 Oct;102(5):1954-9.

http://www.ncbi.nlm.nih.gov/pubmed/19886462

[2] Liu X, Marshall JL, Stary P, Edwards O, Puterka G, Dolatti L, El Bouhssini M, Malinga J, Lage J, Smith CM: Global phylogenetics of Diuraphis noxia (Hemiptera: Aphididae), an invasive aphid species: evidence for multiple invasions into North America. J Econ Entomol. 2010 Jun;103(3):958-65.

http://www.ncbi.nlm.nih.gov/pubmed/20568643

[3] Swanevelder ZH, Surridge AK, Venter E, Botha AM: Limited endosymbiont variation in Diuraphis noxia (Hemiptera: Aphididae) biotypes from the United States and South Africa. J Econ Entomol. 2010 Jun;103(3):887-97.

http://www.ncbi.nlm.nih.gov/pubmed/20568636

[4] Smith CM, Liu X, Wang LJ, Liu X, Chen MS, Starkey S, Bai J: Aphid feeding activates expression of a transcriptome of oxylipin-based defense signals in wheat involved in resistance to herbivory. J Chem Ecol. 2010 Mar;36(3):260-76. Epub 2010 Feb 21.

http://www.ncbi.nlm.nih.gov/pubmed/20229216

[5] Weng Y, Perumal A, Burd JD, Rudd JC: Biotypic diversity in greenbug (Hemiptera: Aphididae): microsatellite-based regional divergence and host-adapted differentiation. J Econ Entomol. 2010 Aug;103(4):1454-63.

http://www.ncbi.nlm.nih.gov/pubmed/20857761

[6] Dogimont C, Bendahmane A, Chovelon V, Boissot N: Host plant resistance to aphids in cultivated crops: genetic and molecular bases, and interactions with aphid populations. C R Biol. 2010 Jun-Jul;333(6-7):566-73. Epub 2010 May 15.

http://www.ncbi.nlm.nih.gov/pubmed/20541167

[7] Nowak H, Komor E: How aphids decide what is good for them: experiments to test aphid feeding behaviour on Tanacetum vulgare (L.) using different nitrogen regimesOecologia. 2010 Aug;163(4):973-84. Epub 2010 May 12.

[8] Hunt E, Gattolin S, Newbury HJ, Bale JS, Tseng HM, Barrett DA, Pritchard J: A mutation in amino acid permease AAP6 reduces the amino acid content of the Arabidopsis sieve elements but leaves aphid herbivores unaffectedJ Exp Bot. 2010;61(1):55-64.
http://www.ncbi.nlm.nih.gov/pubmed/19755569

[9] Gao LL, Kamphuis LG, Kakar K, Edwards OR, Udvardi MK, Singh KB: Identification of potential early regulators of aphid resistance in Medicago truncatula via transcription factor expression profiling. New Phytol. 2010 Jun;186(4):980-94. Epub 2010 Mar 22.

http://www.ncbi.nlm.nih.gov/pubmed/20345634

22.01.2011: Date palm fruits
Production of fructose syrup from discarded Phoenix dactylifera dates [1]
According to Chaira and colleagues 2007, about 50,000 tons of dates are discarded by sorting each year in Tunisia. The authors developed a process to use these fruits for the production of fructose rich syrups at low costs.
The invertase activity of date palm fruits from the Tunisian oasis of Gabes and Jerid were determined, whereas the Gabes variety had highest invertase activity with at least two isoforms.

The invertase extracted from Korkobbi presented an optimal temperature of 45° C, optimum pH of 3,5 to 4,8, Using this invertase a high fructose syrup was obtained from aqueous extract of the Deglet Nour variety during 30 minutes of incubation. The authors used invertase extracted with distilled water and concentrated by ammonium sulfate precipitation at 80% saturation.

Composition of Tunisia date [2]
Chaira and colleagues determined the chemical composition and the radical scavenging activity of flesh and pit of Deglet nour and Alig date. The total sugars may be more than 60% of the dry weight of date flesh. Dates flesh was found to be a good source of several minerals such as potassium varying between 0.61 and 0.72% (dry matter)..

Date pit oil content varied between 10.13% and 12.37%. Less than 6% sugars were determined, in addition, important free radical scavenging activity were found by the authors.

Composition and quality of Tunisian date varieties [3]
Mrabet and colleagues 2008 analysed the composition of Tunisian date palm fruit varieties , taking Deglet Nour as reference. They report that the littoral varieties were very rich in reducing sugars and were high in vitamin C, while Deglet Nour was rich in sucrose and were low in vitamin C. The littoral varieties were classified as soft dates due to their moisture content. The littoral dates were rich in potassium and low in sodium.

Review of date fruit composition [4]
Al-Farsi and Lee 2008 in a review write that the date flesh is low in fat and protein but rich in sugars. Minerals are selenium, copper, potassium, and magnesium. Vitamins B-complex and C are the major vitamins in dates. The flesh is high in dietary fiber, carotenoids and phenolics.
Date seeds contain higher protein as compared to the flesh, have high dietary fiber, phenolics (3942 mg/100 g) and antioxidants (80400 micromol/100 g). The authors suggest tat date seeds may be used as functional food ingredient.

Glycemic index of Omani dates [5]
Ali, Al-Kindi and Al-Said 2009 determined the nutritional quality and glycemic index of three sun-dried date varieties (Khalas, Khsab and Fardh) grown in Oman. The glycemic index (GI) ranged between 47.6 and 57.7. The authors found an iinverse correlation between the fructose fraction and the GI value of dates.

[1] Chaira N, Smaali I, Besbes S, Mrabet A, Lachiheb B, Ferchichi A: Production of fructose rich syrups using invertase from date palm fruits. Journal of Food Biochemistry. 18.10.2010. Doi: 10.1111/j.1745-4514.2010.00487.x
http://onlinelibrary.wiley.com/doi/10.1111/j.1745-4514.2010.00487.x/abstract

[2] Chaira N, Ferchichi A, Mrabet A, Sghairoun M: Chemical composition of the flesh and the pit of date palm fruit and radical scavenging activity of their extracts. Pak J Biol Sci. 2007 Jul 1;10(13):2202-7.
http://www.ncbi.nlm.nih.gov/pubmed/19070182

[3] Mrabet A, Ferchichi A, Chaira N, Mohamed BS, Baaziz Z, Penny TM: Physico-chemical characteristics and total quality of date palm varieties grown in the southern of Tunisia. Pak J Biol Sci. 2008 Apr 1;11(7):1003-8.
http://www.ncbi.nlm.nih.gov/pubmed/18810969

[4] Al-Farsi MA, Lee CY: Nutritional and functional properties of dates: a review. Crit Rev Food Sci Nutr. 2008 Nov;48(10):877-87.
http://www.ncbi.nlm.nih.gov/pubmed/18949591

[5] Ali A, Al-Kindi YS, Al-Said F: Chemical composition and glycemic index of three varieties of Omani dates. Int J Food Sci Nutr. 2009;60 Suppl 4:51-62.
http://www.ncbi.nlm.nih.gov/pubmed/18946799


21.01.2011: Ongoing dioxin scandal in Germany [1]
The high levels of dioxins that have shown up in small amounts of German produce have been traced to a single fats manufacturer, Harles and Jentzsch. Another feed producer based in Damme/Germany has now been traced more than 15 days the begin of investigations. The company had tried to conceal his connections with Harles Jentzsch. Now, about 900 farms have to be closed and wait for dioxin tests.

Dioxin source
Hans Schenkel, a University of Stuttgart professor of agricultural chemistry, said the pattern of dioxins in the fat were similar to dioxines found in kaolin which might be involved in the latest food poisoning. Kaolin can be used up to 3% in animal feed to improve the flow during pumping when moving the animal feed from one store to another and caused a dioxin scandal in 1999. Kaolin is also used to sort out spoiled potatoes and potatoes unsuitable for French fries. The speculations of professor Schenkel were dissipated by investigations of the officials of Münster/Germany.

The chemical and veterinary investigations office of Münster came to the conclusion that residues of the Biodiesel oil production were responsible for the ongoing dioxin contamination of European food chain. The office found that the pattern of the dioxines found in fat, feed and eggs was similar to samples of the Biodiesel refining byproducts.

• 1976 - The Seveso accident.
• 1999 - Dioxin contaminated feed from Belgium
• June 1999 -  German kaolin with high level of dioxin had also been added to feed in Austria and Germany.
• 2003 - Backery waste of Thuringia/Germany with high dioxin levels was used as feed.
• 200 - Several farms were closed in Germany because of dioxin in feed using industrial potato peeling contaminated with poisoned kaolin. [2]
• 2008 - Irish pork with high dioxin levels September until December 2008 about 4000 Tonnes exported to Germany due to feed contaminated with discarded foods which were dried using fuel with high dioxin content. Dioxin levels of some samples of Irish pork exceeded the WHO-TEQ by 2500 times.
• 2010 - May 2010 - Organic eggs were contaminated with dioxin from feed using maize from Ukraine .
• April/December 2010 - High dioxin in eggs, poultry, liquid egg yolk made of these eggs were used for bakery products and mayonnaise. Contaminated feed has also sold for dairy cattle farms.