Protein isolates from two Mediterranean legumes: Lathyrus clymenum and Lathyrus annuus. Chemical composition,functional properties and protein characterisation

Protein isolates were analysed from two Mediterranean legumes, Lathyrus clymenum and L. annuus. Protein isolates were prepared by alkaline extraction, including sodium sulphite and acid precipitation of Lathyrus proteins at their isoelectric point (pH 4.5). The percentage of proteins recovered from L. annuus and L. clymenum flours during the preparation of the protein isolates was around 60%. Chemical composition, nutritional parameters, main functional properties and protein composition of Lathyrus protein isolates were studied. L. annuus and L. clymenum protein isolates contained 81.07% and 82.4% of proteins, respectively, and they have a balanced content of essential amino acids, except for sulphur amino acids, with respect to the FAO pattern. The in vitro protein digestibility increased in the protein isolates to 93% and 95% in L. annuus and L. clymenum, respectively. Functional properties were similar to those observed in other legumes protein isolates. These results confirm the interest of local crops as sources of high value protein products obtained after convenient protein extraction procedures and the removal of antinutritional components. These high added value protein isolates are of interest for the food industry and for the revalorisation of L. annuus and L. clymenum favouring the bioconservation of Lathyrus.     

Effect of damaged starch on acrylamide formation in whole wheat flour based Indian traditional staples, chapattis and pooris

Variation in acrylamide content of two Indian traditional products, chapatti and poori was observed with respect to the damaged starch content in whole wheat flour of different wheat varieties from which these products were prepared. Wheat cultivar ‘lokwan’ was milled by altering mill aperture, feed rate and moisture content to obtain whole wheat flour with damaged starch contents ranging from 6.23% to 28.12%. Acrylamide content of the chapatti and pooris prepared from such flours ranged from 12.5 to 65.5 μg/kg in chapatti, and 25.5 to 130.5 μg/kg in pooris. Impact of several additives showed 10 μmol/g flour citric acid, and 100 μmol/g flour calcium chloride to reduce acrylamide in pooris by approximately 54% and 72%, respectively, without altering the sensory analysis of the products.     

Varieties of antioxidant and antibacterial properties of Ecklonia stolonifera and Ecklonia kurome products harvested and processed in the Noto peninsula,Japan

Ecklonia stolonifera and Ecklonia kurome are traditional edible brown algae in the fisheries towns in Far East Asia. In the Noto Peninsula area, Ishikawa, Japan, both the Ecklonia are called ‘kajime’ and people believe that the algae improve the property of blood. To determine the varieties of antioxidant and antibacterial properties E. stolonifera and E. kurome products, assays for total phenolic content and antioxidant activities, including DPPH radical-scavenging activity, superoxide anion radical-generated by non-enzymatic system, ferrous-reducing power and WST-8, a tetrazolium salt, redox activity of four dried and two boiled E. stolonifera, and four dried and two raw E. kurome preparations were tested in this study. Furthermore, antibacterial activity of the products was tested. Though the total phenolic content, the antioxidant activity and the antibacterial activities of E. stolorifera and E. kurome products were high, these properties were varied by manufacturers or each product. Especially, two dried and two boiled products of E. stolonifera showed low activities. The results of this study indicate that the contents of functional compounds and their activities were affected or decreased greatly by the processing method.     

Barcode High Resolution Melting (Bar-HRM) analysis for detection and quantification of PDO “Fava Santorinis” (Lathyrus clymenum) adulterants

Legumes considered as one of the most important crops worldwide. Due to high price as a PDO product, commercial products of “Fava Santorinis” are often subjected to adulterations from other legume products coming from other Lathyrus or Vicia and Pisum species. Using plant DNA barcoding regions (trnL and rpoC) coupled with High Resolution Melting (Bar-HRM) we have developed a method allowing us to detect and authenticate PDO “Fava Santorinis”. Bar-HRM proved to be a very sensitive tool able to genotype Lathyrus and its closed relative species and to detect admixtures, being sensitive enough to as low as 1:100 of non-“Fava Santorinis” in “Fava Santorinis” commercial products. In conclusion, Bar-HRM analysis can be a faster, with higher resolution and cost effectiveness alternative method to authenticate PDO “Fava Santorinis” and to quantitatively detect adulterations in “Fava Santorinis” with other relative commercial “Fava” food products.     

Biotransformation of phenolics (isoflavones,flavanols and phenolic acids) during the fermentation of cheonggukjang by Bacillus pumilus HY1

Changes in β-glycosidase, esterase activities, isoflavone, flavanols and phenolic acid during the fermentation of Korean whole soybean fermented food cheonggukjang by Bacillus pumilus HY1 were investigated. The levels of aglycones, flavanols and gallic acid increased, while the β-glucosidase activity, esterase activity, glycosides content (except for acetylglycosides) and flavanol gallates decreased. Total isoflavone content slightly decreased after 60 h of fermentation, while total flavanol and phenolic acid content increased. The highest levels of daidzein (aglycone type) and acetyldaidzin (glycoside type) were recorded after 48 h of fermentation. The levels of catechin, epicatechin and gallic acid also increased during fermentation. However, total contents of glycosides, malonylglycosides and flavanol gallates decreased by about 80%, 90% and 60% during 60 h of fermentation, respectively. In addition, total phenolic content increased markedly during fermentation, while levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity increased. Hence, it would be beneficial for the food industry if components of cheonggukjang could be separated and developed into functional products.     

Synbiotic potential of fresh cream cheese supplemented with inulin and Lactobacillus paracasei in co-culture with Streptococcus thermophilus

The influence of the addition of Lactobacillus paracasei and Streptococcus thermophilus on the fructan content at the beginning and at the end of storage at 4 ± 1 °C of a potentially synbiotic fresh cream cheese manufactured with inulin was investigated. Three cheese-making trials were prepared, all supplemented with a lactic culture of S. thermophilus (T1, T2 and T3). L. paracasei subsp. paracasei was added in T1 and T2. Inulin was added in T2 and the fructan content was measured after 1 and 21 days of storage. Samples of T2 possessed similar mean concentrations of fructans after 1 and 21 days of storage, 7.32% and 7.27%, respectively, and no significant difference was observed. These results indicated that the metabolism of starter and probiotic bacteria did not degrade the fructans present in those cheeses. Additionally, synbiotic cheeses possessed a fructan content higher than 7 g per 100 g, sufficient to confer prebiotic potential during the entire storage period of these products.     

Trans fatty acids in a range of UK processed foods

A survey to determine the trans fatty acid content of a range of processed foods was carried out in response to recent reformulation work by the food industry to lower the artificial trans fatty acid content of processed products. Sixty two composite samples, made up of between 5 and 12 sub-samples, were collected in 2010 and were analysed for fatty acids, and a range of nutrients. The foods analysed included pizza, garlic bread, breakfast cereals, quiche, fat spreads, a range of fish and meat products, chips, savoury snacks, confectionery and ice cream. Levels of trans fatty acids were reduced considerably compared with previous UK analyses of similar foods where comparisons are possible. Concentrations of trans elaidic acid (t9-C18:1) from hydrogenated oils in all samples were <0.2 g/100 g food. These results confirm information provided by the food industry in 2007 on the levels of trans fats in key processed food sectors.     

Variations in essential oil and fatty acid composition during Myrtus communis var. italica fruit maturation

The essential oil and fatty acid composition of Myrtus communis var. italica fruit during its ripening was determined. The effect of the harvesting time on some physical properties of Myrtus fruits, fruit weight and moisture content, were significant. The increase of fruit weight (from 2.54 to 8.79 g% fruits) during ripeness was correlated positively with that of moisture content (from 28% to 72%). Fruit essential oil yields varied from 0.003% to 0.01% and showed a remarkable increase at 60 days after flowering to reach a maximum of 0.11%. Forty-seven volatile compounds were identified in fruit essential oils; 1,8-cineole (7.31–40.99%), geranyl acetate (1.83–20.54%), linalool (0.74–18.92%) and α-pinene (1.24–12.64%) were the main monoterpene compounds. Total fatty acid contents varied from 0.81% to 3.10% during fruit maturation and the predominant fatty acids were linoleic (12.21–71.34%), palmitic (13.58–37.07%) and oleic (6.49–21.89%) acids. The linoleic acid proportions correlated inversely with palmitic and oleic acids during all the stages of ripening.     

Enhanced antioxidant activity of Monascuspilosus fermented products by addition of ginger to the medium

The fermented products of Monascus sp. are known for their antihypercholesterolaemic effects, however, their antioxidant activities are different from those of many plant-derived foods. To evaluate the effect of ginger addition into the medium on the antioxidant activity of Monascuspilosus fermented products, we cultured uninoculated PDB medium (PDB), inoculated PDB medium (MP), uninoculated ginger-containing medium (PDBG), and inoculated ginger-containing medium (MPG). The broth and mycelia were collected, freeze-dried, and extracted to evaluate their free radical scavenging activities, inhibition of peroxidation, phenolic content, inhibition of DNA damage, cellular antioxidant activity, and expression of the antioxidant enzymes. The results showed that MPG had significantly higher antioxidant activity than PDB, MP, and PDBG at all fermentation time points. Moreover, the fermentation process significantly increased the antioxidant activities of MPG. After the inherent level of antioxidant capacity was increased, the modified M. pilosus fermented product demonstrated a higher anti-atherosclerotic value than the unmodified product.     

Prevalence and comparison of Streptococcus infantarius subsp. infantarius and Streptococcus gallolyticus subsp. macedonicus in raw and fermented dairy products from East and West Africa

Streptococcus infantarius subsp. infantarius (Sii) and Streptococcus gallolyticus subsp. macedonicus are members of the Streptococcus bovis/Streptococcus equinus complex (SBSEC) associated with human infections. SBSEC-related endocarditis was furthermore associated with rural residency in Southern Europe. SBSEC members are increasingly isolated as predominant species from fermented dairy products in Europe, Asia and Africa. African variants of Sii displayed dairy adaptations to lactose metabolism paralleling those of Streptococcus thermophilus including genome decay. In this study, the aim was to assess the prevalence of Sii and possibly other SBSEC members in dairy products of East and West Africa in order to identify their habitat, estimate their importance in dairy fermentation processes and determine geographic areas affected by this potential health risk. Presumptive SBSEC members were isolated on semi-selective M17 and SM agar media. Subsequent genotypic identification of isolates was based on rep-PCR fingerprinting and SBSEC-specific16S rRNA gene PCR assay. Detailed identification was achieved through application of novel primers enhancing the binding stringency in partial groES/groEL gene amplification and subsequent DNA sequencing. The presence of S. thermophilus-like lacS and lacZ genes in the SBSEC isolates was determined to elucidate the prevalence of this dairy adaptation. Isolates (n = 754) were obtained from 72 raw and 95 fermented milk samples from Côte d'Ivoire and Kenya on semi-selective agar media. Colonies of Sii were not detected from raw milk despite high microbial titers of approximately 10⁶ CFU/mL on M17 agar medium. However, after spontaneous milk fermentation Sii was genotypically identified in 94.1% of Kenyan samples and 60.8% of Kenyan isolates. Sii prevalence in Côte d'Ivoire displayed seasonal variations in samples from 32.3% (June) to 40.0% (Dec/Jan) and isolates from 20.5% (June) to 27.7% (Dec/Jan) present at titers of 10⁶–10⁸ CFU/mL. lacS and lacZ genes were detected in all Kenyan and 25.8% (June) to 65.4% (Dec/Jan) of Ivorian Sii isolates. Regional differences in prevalence of Sii and dairy adaptations were observed, but no clear effect of dairy animal, fermentation procedure and climate was revealed. Conclusively, the high prevalence of Sii in Kenya, Côte d'Ivoire in addition to Somalia, Sudan and Mali strongly indicates a pivotal role of Sii in traditional African dairy fermentations potentially paralleling that of typical western dairy species S. thermophilus. Putative health risks associated with the consumption of high amounts of live Sii and potential different degrees of evolutionary adaptation or ecological colonization require further epidemiologic and genomic investigations, particularly in Africa.     

Short-term toxicological evaluation of Terminalia catappa, Pentaclethra macrophylla and Calophyllum inophyllum seed oils in rats

The purpose of this study was to evaluate the toxicological effects of feeding the oils of Calophyllum inophyllum, Pentaclethra macrophylla and Terminalia catappa to rats. The effects on physical appearance, feed intake, weight gain, plasma and tissue cholesterol and triacyglycerol levels in rats with 5% of the oils in normal rat feed were determined. Weekly monitoring of the rats showed good physical appearance and steady weight gain, with no mortality recorded for the period of the study. Haematological analysis of the rats indicated that they were not anaemic. Histopathotogical examination of the sections of the heart, liver, kidney and spleen revealed moderate (T. catappa oil) to severe fatty change and necrosis in the liver. Glomerulonephrotic changes in the kidneys of rats fed with T. catappa oil were moderate, while it was severe in the group fed with P. macrophylla oil. Severe myocardiac necrosis as well as atherosclerotic clefts in vasa vasori was observed in the vasa vasori of the hearts of rats fed with P. macrophylla oil. This change was moderate in the heart of rats fed with C. inophyllum, while no such observation was made in the group fed with T. catappa oil. There was a significant difference in the plasma cholesterol levels of the rats fed with C. inophyllum and T. catappa oils when compared with the control rats, while those fed with P. macrophylla oil had no significant difference. The oil of T. catappa appears more suitable for consumption than the oils from C. inophyllum and P. macrophylla. Fatty acid analysis of the oils showed that they have high amounts of unsaturated fatty acids with linoleic and oleic acids as the major ones.     

Chitin content of cultivated mushrooms Agaricus bisporus, Pleurotus ostreatus and Lentinula edodes

The chitin contents of pileus and stipes of fruit bodies of Agaricus bisporus, Pleurotus ostreatus and Lentinula edodes (shii take) were determined and compared. The fruit bodies of different, common varieties of the cultivated mushroom species were taken from Hungarian and German large-scale farming. The analytical procedure was carried out on the powder of cleaned, dried and milled pileus and stipes. The pileus of A. bisporus variety ‘K-23’ showed a significant decrease (p < 0.05) during the cultivation’s flushes (breaks), 1–3, while the chitin level of stipes seemed to be constant. The other analysed A. bisporus varieties (var. ‘158’, ‘K-7’, ‘Sylvan A-15’, ‘Sylvan 608’, and Le Lion C-9) had practically the same chitin levels. This indicates that the chitin content is a stable characteristic of the species and there are no significant differences between the different varieties. The chitin levels of pileus and stipes were not significantly different (for A. bisporus, 6.68 and 7.25) but showed significant differences for P. ostreatus (p < 0.05) and L. edodes (p < 0.001). In the case of the latter two species, the pileus had the higher and the stipe the lower chitin content. The presented data confirm that a mushroom saprotrophic (A. bisporus) had higher chitin level than had the wood-rotting ones (P. ostreatus, L. edodes).     

Characterization and in vitro bioavailability of β-carotene: Effects of microencapsulation method and food matrix

The objectives of this study were to determine the effect of microencapsulation method on physical properties and in vitro release and bioavailability of three types of β-carotene: a spray-dried powder of β-carotene and maltodextrin, commercially available water-dispersible β-carotene powder, and chitosan-coated β-carotene alginate. In vitro digestion trials were conducted with and without food matrices (yogurt, pudding) to elucidate the effect of food matrix on in vitro release and bioavailability. Microencapsulation method significantly affected (p < 0.05) water activity, moisture content, and particle size. The maltodextrin powder had the lowest moisture content (3.5%) and the smallest volume mean diameter (10.5 μm), whereas the chitosan-alginate beads had the lowest water activity (0.195). The maltodextrin powder had the highest surface β-carotene content (39.5%), while the commercial water-dispersible powder had the highest β-carotene content (10%). The microencapsulation method significantly influenced (p < 0.05) release and incorporation into micelles, regardless of food matrix. Water-dispersible β-carotene achieved the highest release (93.3%) and the highest incorporation into micelles (36.4%) in the absence of a food matrix, and the highest release (34.8%) and the highest micelle content (17.0%) with pudding. Food matrix significantly decreased release and micelle incorporation (p < 0.05), with yogurt decreasing release and micelle incorporation more than pudding.     

Survey of Listeria monocytogenes, Salmonella spp. and Escherichia coli O157:H7 in raw ingredients and ready-to-eat products by commercial real-time PCR kits

Real-time PCR (RTiPCR) assays including enrichment stage were evaluated for the rapid detection of Listeria monocytogenes, Salmonella spp. and Escherichia coli O157:H7 in raw ingredients and ready-to-eat products using molecular beacon probes available as commercial kits (WARNEX Genevision, Canada & AES Chemunex detection system, France). The accuracy of the assays was evaluated analyzing 1032 naturally contaminated food samples in combination to the conventional cultural methods. Presence/absence testing of the above pathogens was performed in 25 g samples of each product. In case of L. monocytogenes of 39 positive RTiPCR samples, 37 were confirmed by the cultural method (based on McNemar's test the difference between the two methods is insignificant). The highest incidence of L. monocytogenes in food products was found in desserts and the second highest in frozen pastries. None of the samples were cultural positive but negative in the RTiPCR test. One among the 343 investigated samples was positive for Salmonella spp. by RTiPCR and the cultural method. Out of 333 samples analyzed for E. coli O157:H7 no positive sample was detected. RTiPCR-based methods proved to be powerful tools for fast, sensitive and accurate pathogen detection in raw food ingredients and ready-to-eat products.     

Characterization of Longissimus thoracis, Semitendinosus and Masseter muscles and relationships with technological quality in pigs. 2. Composition of muscles

The composition of three porcine muscles (Longissimus thoracis: LT, Semitendinosus: ST, Masseter: MS) was characterized and its link with muscle quality was evaluated. The LT muscle had a higher content of tyrosine, tryptophan, and carbohydrates and a lower content of vitamin E and haem iron than the MS muscle, while the ST had similar composition to MS but a lower content of haem iron. Large differences between muscles were observed in relative amounts of most of the major fatty acids. The LT muscle had higher saturated fatty acids (SFA) and n− 6:n− 3 fatty acid ratio, and lower polyunsaturated fatty acids (PUFA), PUFA:SFA ratio, unsaturation index and average fatty acid chain length than the ST and MS muscles. Muscle pH, redness and chroma were positively correlated with vitamin E and unsaturated lipids and negatively correlated with tyrosine, tryptophan, carbohydrates and saturated lipids, whereas muscle lightness and expressible juice showed similar correlations but an opposite sign with these variables.     

Satureja horvatii essential oil: In vitro antimicrobial and antiradical properties and in situ control of Listeria monocytogenes in pork meat

The dominant compounds in Satureja horvatii oil were p-cymene (33.14%), thymol (26.11%) and thymol methyl ether (15.08%). The minimum inhibitory concentration (MIC) varied from 0.03 to 0.57 mg/mL for bacteria, and from 0.56 to 2.23 mg/mL for yeast strains, while minimum bactericidal/yeast-cidal concentration (MBC/MYC) varied from 0.07 to 1.15 mg/mL and 1.11 to 5.57 mg/mL for bacteria and yeasts, respectively. The antiradical potential of the essential oil was evaluated using hydroxyl radical (•OH) generated in Fenton reaction. The meat preserving potential of essential oil from Satureja horvatii was investigated against L. monocytogenes. Essential oil successfully inhibited development of L. monocytogenes in pork meat. Sensorial evaluation on flavor and color of meat was performed. The color and flavor of meat treated with essential oil improved after 4 days of storage. S. horvatii essential oil can act as a potent inhibitor of food spoiling microorganisms, in meat products and also can be a useful source of natural antioxidants.     

Direct quantification of fatty acids in dairy powders with special emphasis on trans fatty acid content

In this study a validated procedure for accurate determination of fatty acids in dairy products, with special emphasis on total trans fatty acids (TFA) content is presented. Dairy fat naturally contains 4–6% of trans fatty acids, mainly trans-octadecenoic acids (i.e. vaccenic acid), and 0.3–1.5% of conjugated linoleic acids (CLA). The proposed procedure does not require lipid extraction, and transesterification of lipids could be carried out directly on dairy products. Optimal analytical conditions have been developed to allow accurate determination of TFA content without prior fractionation of cis/trans FAME isomers by thin-layer chromatography. The methodology requires the use of a highly polar open tubular capillary column having at least 100 m length. CLA and other fatty acids from C4:0 (butyric) acid to long-chain polyunsaturated fatty acids (LC-PUFAs) could also be analyzed. Therefore, the methodology presented is versatile and could be used for both targeted analysis (e.g. determination of TFA in dairy products) and determination of the broad fatty acid profile in dairy products.     

Effect of chitin on the antagonistic activity of Rhodotorula glutinis against Botrytis cinerea in strawberries and the possible mechanisms involved

The influence of chitin on the efficacy of Rhodotorula glutinis in controlling postharvest grey mould of strawberries and the possible mechanisms involved were investigated. The results showed that the antagonistic activity of R. glutinis harvested either from the culture media of NYDB amended with chitin at 0.5% or from the culture media in which chitin was the sole carbon source (NYCB) was improved greatly compared with that without chitin. The application of R. glutinis cultivated in the culture media of the chitin-supplement (0.5%) induced higher β-1,3-glucanase activity and reduced more MDA content of strawberries compared with that R. glutinis cultivated in the NYDB. Moreover, the control efficacy of the cell-free filtrate of the chitin-supplement culture media (0.5%) and NYCB were higher than that of cell-free culture filtrates of NYDB in 2 days incubation, with the associated high level of chitinase activity.