Low and high temperatures for the control of cowpea beetle, callosobruchus maculatus (F.) (coleoptera: Bruchidae) in chickpeas

Chickpea (Cicer arietinum L.; Leguminasae) is an important pulse crop grown, around the world. The whole grain of chickpea is damaged by the cowpea seed beetle, Callosobruchus maculatus (Coleoptera: Bruchidae), which is the most important field-carry-over storage pest of pulses. The management of this insect in storage using chemicals leads to insecticide residues in grains and insecticide resistance development in insects. Thermal disinfestation is one of the means of physical insect control. Eggs, larvae, pupae and adults were held at 42 or 0 °C for varying durations. Pupae and adults were equally heat tolerant. The lethal time to reduce survival by 50% (LT₅₀) at 42 °C for eggs, larvae, pupae and adults were 18, 57, 78 and 71 h, respectively. Pupa was the most cold-tolerant stage. The LT₅₀ at 0 °C for eggs, larvae, pupae and adults were 3, 8, 10 and 4 d, respectively. The LT₅₀ for pupae were 4907, 4262, 336, 36 and 13 min at the grain temperature of 42, 45, 50, 55 and 60 °C, respectively. The LT₅₀ of pupae at 0,−5,−10 and −15 °C were 274, 122, 7 and 2 h, respectively.     

A comparison of the physicochemical and sensory characteristics of alheira samples from different-sized producers

Alheira is a traditional Portuguese meat product made from boiled meat, usually pork and/or poultry, and bread. The physicochemical and sensory properties of alheira were analyzed to determine the relationships between them and to evaluate how they are affected by the product’s origin i.e. if is produced on a small or industrial scale. The most important variables used to characterize alheira are: color, visual evaluation of the amount of meat and bread, paprika aroma, clamminess and fibrousness, water activity, moisture, fat, carbohydrate content, hardness and color parameters (L^∗, a^∗,  and b^∗). Principal component analysis demonstrated that drying has a major effect on these characteristics, as it plays a part in the product’s physical make-up. Using these parameters it was possible to ascertain that industrial products enjoyed higher levels of consumer acceptability, given that they contain a higher proportion of meat and undergo a shorter drying process.     

A study of the in vitro protein digestibility of indica and japonica cultivars

Protein digestibility was determined in 18 indica and japonica raw milled rices using an in vitro pH-drop method with three- or four-enzyme system. Similar protein digestibility was found between indica and japonica rices, which is in agreement with the in vivo digestibilities in human. Cooking improved protein digestibility in the four-enzyme assay, while reducing agents exhibited apparent inhibition in multienzyme digestibility of indica and japonica rices. A significant correlation was detected between protein content and the estimates of digestibility, whereas no significant correlation was found between amylose content and digestibility estimates. SDS–PAGE analysis showed a significant difference in the degradation extent of prolamin between multienzyme and pepsin digestion, which might contribute to the inconsistence between results of this study and previous findings that in vitro protein digestibility of japonica rice was higher than that of indica rice. In addition, our results supported the previous report that waxy gene product level is not a major determinant of protein digestibility in milled rice.     

Selenium contents of Portuguese commercial and wild edible mushrooms

The selenium contents of 66 mushroom samples, wild growing or commercially available in Portugal, fresh, canned or dried, were determined. The samples consisted of 18 mushroom species, mainly selected in accordance with their availability and consumer preference. The selenium contents varied considerably between different mushroom species. The highest selenium contents were found in the wild species Boletus aestivalis (48.5 mg/kg dry weight, DW), Boletus pinophilus (19.9 mg/kg DW), Boletus edulis (14.9 mg/kg DW), Boletus aereus (12.3 mg/kg DW), Boletus fragans and Boletus spretus (∼2 mg/kg DW). Other mushrooms having considerable selenium contents included Marasmius oreades (1.5 mg/kg DW), Agaricus bisporus “Portobello” (1.25 mg/kg DW), A. bisporus (1.0 mg/kg DW) and Russula cyanoxantha (0.72 mg/kg DW). The selenium contents of these mushrooms are sufficient to provide nutritionally significant amounts in relation to the total daily intake of selenium. Other edible mushrooms, such as Lentinula edodes, Pleurotus ostreatus, Cantharellus cibarius,Craterellus cornucopioides and Lepista nuda, contained only small amounts of selenium. The importance of these mushrooms as a source of selenium is therefore marginal.     

Antioxidant and antibacterial activities of exopolysaccharides from Bifidobacterium bifidum WBIN03 and Lactobacillus plantarum R315

The objective of this study was to investigate the antioxidant and antibacterial activities of exopolysaccharide (EPS) from Bifidobacterium bifidum WBIN03 (B-EPS) and Lactobacillus plantarum R315 (L-EPS). The 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical scavenging, hydroxyl radical-scavenging, and superoxide radical-scavenging abilities were measured to evaluate antioxidant activity. Inhibition of erythrocyte hemolysis and lipid peroxidation was also measured. Both B-EPS and L-EPS had strong scavenging ability against DPPH and superoxide radicals at high concentration. The inhibitory effect of B-EPS on erythrocyte hemolysis was stronger than that of L-EPS in a concentration range from 0.30 to 1.00 mg/mL, whereas the hydroxyl scavenging ability of L-EPS (39.15 ± 0.58%) was significantly higher than that of 0.15 mg/mL ascorbic acid (24.33 ± 1.17%) and B-EPS (17.89 ± 3.30%) at 0.10 mg/mL. The inhibition of lipid peroxidation of 0.50 mg/mL B-EPS and L-EPS was 13.48 ± 1.74% and 12.43 ± 0.51%, respectively, values lower than that of ascorbic acid at the same concentration (23.20 ± 1.41%). Furthermore, all these abilities were enhanced in a concentration-dependent manner. Agar diffusion assay showed that both EPS exhibited antibacterial activities against tested pathogens such as Cronobacter sakazakii, Escherichia coli, Listeria monocytogenes, Staphyloccocus aureus, Candida albicans, Bacillus cereus, Salmonella typhimurium, and Shigella sonnei at 300 μg/mL. In conclusion, both EPS have antimicrobial and antioxidant activities and could have applications in the food industry.     

Antioxidant and antimicrobial activities of Laetiporus sulphureus (Bull.) Murrill

Antioxidant capacity and antimicrobial activities of Laetiporus sulphureus (Bull.) Murrill. extracts obtained with ethanol were investigated in this study. The study was aimed at determining the antioxidant activity (DPPH free radical-scavenging, β-carotene/linoleic acid systems), total phenolic content and total flavonoid concentration of L. sulphureus. Inhibition values both of L. sulphureus ethanol and the standards increased parallel with the elevation of concentration in the linoleic acid system. Inhibition values of L. sulphureus (LS) extract, BHA and α-tocopherol standards were found to be 82.2%, 96.4% and 98.6%, respectively, at a concentration of 160 μg/ml. DPPH free radical-scavenging activity was found to exhibit 14%, 26%, 55% and 86% inhibition, respectively, at concentrations of 100, 200, 400 and 800 μg/ml. Total flavanoids were 14.2 ± 0.12 μg mg⁻¹ (quercetin equivalent) while the phenolics were 63.8 ± 0.25 μg mg⁻¹ (pyrocatechol equivalent) in the extract. Positive correlations were found between total phenolic content in the mushroom extracts and their antioxidant activities. Edible mushrooms may have potential as natural antioxidants. L. sulphureus showed narrow antibacterial activity against Gram-negative bacteria and strongly inhibited the growth of the Gram-positive bacteria tested. The crude extract exhibited high anticandidal activity on Candida albicans. Therefore, the extracts could be suitable as antimicrobial and antioxidative agents in the food industry.     

Ultrasound-assisted production of bioethanol by simultaneous saccharification and fermentation of corn meal

An ultrasound-assisted liquefaction as a pretreatment for bioethanol production by simultaneous saccharification and fermentation (SSF) of corn meal using Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. Ultrasound pretreatment (at a frequency of 40 kHz) was performed at different sonication times and temperatures, before addition of liquefying enzyme. An optimal duration of the treatment of 5 min and sonication temperature of 60 °C were selected, taking into account glucose concentration after the liquefaction step. Under the optimum conditions an increase of glucose concentration of 6.82% over untreated control sample was achieved. Furthermore, the SSF process kinetics was assessed and determined, and the effect of ultrasound pretreatment on an increase of ethanol productivity was investigated. The obtained results indicated that the ultrasound pretreatment could increase the ethanol concentration by 11.15% (compared to the control sample) as well as other significant process parameters. In this case, the maximum ethanol concentration of 9.67% w/w (which corresponded to percentage of the theoretical ethanol yield of 88.96%) was achieved after 32 h of the SSF process. A comparison of scanning electron micrographs of the ultrasound-pretreated and untreated samples of corn meal suspensions showed that the ultrasound stimulated degradation of starch granules and release of glucose, and thereby accelerated the starch hydrolysis due to the cavitation and acoustic streaming caused by the ultrasonic action.     

How three adventitious lactic acid bacteria affect proteolysis and organic acid production in model Portuguese cheeses manufactured from several milk sources and two alternative coagulants

Model cheeses were manufactured according to a full factorial experimental design to help shed light on the individual and combined roles played by 3 native lactic acid bacteria (Lactococcus lactis ssp. lactis, Lactobacillus brevis, and Lactobacillus plantarum) upon proteolysis and organic acid evolution in cheese. The model cheeses were manufactured according to a generally representative Portuguese artisanal protocol, but the (ubiquitous) adventitious microflora in the cheesemaking milk were removed via sterilization before manufacture; therefore, the specific effects of only those lactic acid bacteria selected were monitored. In addition, 2 types of coagulant (animal and plant) and 3 types of cheesemaking milk (cow, sheep, and goat) were assessed to determine their influence on the final characteristics of the model cheeses. The nature of the coagulant appeared to be essential during the first stage of proteolysis as expected, whereas the contribution of those bacteria to the pools of total free AA and organic acids was crucial afterward. This was especially so in terms of the differences observed in the metabolisms of lactic acid (in the case of Lactococcus spp.) as well as acetic and citric acids (in the case of Lactobacillus spp.).     

Glucosinolate content and myrosinase activity evolution in three maca (Lepidium meyenii Walp.) ecotypes during preharvest,harvest and postharvest drying

Glucosinolate profiles, glucosinolate contents and myrosinase activity were evaluated in yellow, red and black hypocotyls of maca during pre-harvest, at harvest and during post-harvest drying. At harvest, six glucosinolates (GLs) were identified: 5-methylsulfinylpentyl, 4-hydroxybenzyl, benzyl, 3-methoxybenzyl, 4-hydroxy-3-indolylmethyl and 4-methoxy-3-indolylmethyl, of which benzyl glucosinolate was the most abundant in the three ecotypes, representing 80% of the total GLs. A significant increase in GLs was observed for the three ecotypes during the 90 days before harvest and during the 15–30 days of post-harvest drying. This was followed by an important decrease of GLs during the 30–45 day period, which was attributed to cell breakdown, due to fluctuations in temperatures during the drying process, and was correlated with a high myrosinase action. During the last period of post-harvest drying, GLs were much lower and correlated to lower myrosinase activity and lower maca hypocotyl humidity. A combination of artisanal and other processing techniques should be utilised, in order to best preserve maca glucosinolates.     

Detection and localization of a peptidoglycan hydrolase in Lactobacillus delbrueckii subsp. bulgaricus

Peptidoglycan hydrolase activities in Lactobacillus delbrueckii subsp. bulgaricus were detected by analysis of bacterial extracts on denaturing polyacrylamide gel electrophoresis containing lyophilized Micrococcus lysodeikticus cells as substrate. A hydrolase with an estimated molecular mass of 80 kDa was found to cross-react on Western blot with monoclonal antibodies raised against muramidase-2 of Enterococcus hirae. These antibodies were also used to demonstrate that the method of cell sample preparation affected protein detection. Slot and Western blots indicate that the peptidoglycan hydrolase from L. bulgaricus is bound to the cell wall. Immuno-labeling followed by optical and electron microscopic observations suggest that this hydrolase is intracellular and restricted mainly to the space between the membrane and the cell wall.     

Efficacy of killer yeasts in the biological control of Penicillium digitatum on Tarocco orange fruits (Citrus sinensis)

Killer Saccharomyces cerevisiae and Wickerhamomyces anomalus yeast strains were tested as biocontrol agents against Penicillium digitatum, one the most important causes of postharvest decay in orange fruits.     

Investigation of candidate genes for glycolytic potential of porcine skeletal muscle: Association with meat quality and production traits in Italian Large White pigs

The objective of this study was to investigate the association of DNA markers in candidate genes for glycolytic potential on meat quality parameters (pH(1), pH(u), glycogen and lactate content and glycolytic potential of semimembranosus muscle) and estimated breeding values (EBVs) for average daily gain, lean cuts, back fat thickness, ham weight, and feed:gain ratio in 272 Italian Large White pigs. Three mutations in the PRKAG3 gene (T30N, G52S and I199V) were investigated as well as single nucleotide polymorphisms in two other skeletal muscle genes (PGAM2 and PKM2) involved in the glycolytic pathway. Association analysis with the PRKAG3 markers showed significant results (P<0.05) only for pH(1) (I199V, with significant additive effect) and lactate content (T30N), confirming, at least in part, the effects of this gene on meat quality traits. Significant association (P<0.05) was also observed for PGAM2 and ham weight EBV with significant additive and dominance effects. PKM2 was associated with average daily gain, lean cuts (P<0.001), back fat thickness and feed:gain ratio (P<0.05), with significant additive and/or dominance effects on these traits. PKM2 encodes for a key enzyme of the muscle glycolytic pathway and maps on porcine chromosome 7 where other studies have reported important QTL for the same traits. These data might suggest an important function of this gene in the mechanisms that produce the observed effects. The results will be important to evaluate the inclusion of some of these DNA polymorphisms in marker assisted selection programs.     

Molecular identification of the microbiota of peeled and unpeeled brown shrimp (Crangon crangon) during storage on ice and at 7.5 °C

The dominant microbiota of brown shrimp (Crangon crangon) were systematically identified during storage under different conditions. Freshly caught shrimp were processed on board the fishing vessel under the best possible hygienic conditions (IDEAL), unpeeled and manually (sterile) peeled, then stored on ice and at 7.5 °C until microbiologically spoiled. Results were compared with industrially processed (INDUSTRIAL) shrimp. Isolates grown on various media were identified by 16S rRNA and gyrB gene sequencing. We examined the total microbiota and microbial population shifts of shrimp under various storage conditions using denaturant gradient gel electrophoresis (DGGE). The microbiota differed somewhat during storage and among the various storage conditions; however, members of the genera Psychrobacter and Pseudoalteromonas were found to dominate the microbiota of all shrimp samples regardless of processing procedures or storage conditions. Most isolates could be identified by gyrB gene sequencing as Psychrobacter immobilis or Psychrobacter cibarius. Also Pseudoalteromonas nigrifaciens, Pseudoalteromonas elyakovii or Pseudoalteromonas paragorgicola dominated the microbiota of brown shrimp during storage. Also species from the genera Planocuccus, Exiguobacterium, Carnobacterium, Pseudomonas, Chryseobacterium and Staphylococcus were detected during storage of brown shrimp.     

Assessment of in vitro antioxidant capacity of stem and leaf extracts of Rabdosia serra (MAXIM.) HARA and identification of the major compound

The leaf and stem of Rabdosia serra were extracted by different solvents in this work. The results indicated that 60% ethanol was the most suitable solvent for efficiently extracting antioxidants with strong free radical-scavenging capacity and ferrous ion chelating capacity. The butanol and 60% ethanol extracts of stem, methanol and 60% ethanol extracts of leaf were analysed by HPLC–PDA. A similar chemical composition was observed for these stem and leaf extracts. The major compound was obtained by column chromatography and identified by mass spectrometry and nuclear magnetic resonance spectroscopy, which was confirmed to be rosmarinic acid. The contents of rosmarinic acid were in a descending order: butanol extract of stem > 60% ethanol extract of leaf > 60% ethanol extract of stem > methanol extract of leaf.     

Structural and functional properties of starches from field peas

Starch was isolated from seven varieties of field peas (Pisumsativum L.) and characterised using a combination of physical, chemical and functional tests. The total starch content of the peas ranged between 34% and 42.7% of dry matter, and the amylose content of the starch was between 35% and 38%. Average particle diameter of the seven starches varied between 21.4 and 26.1 μm. All of the pea starches gave a typical C-type X-ray diffraction pattern, with relative crystallinity ranging between 36% and 55% and the proportion of B-type crystallites between 3.8% and 30.4%. Although there were only small differences between the starches in amylose content, they displayed significant variability in functional properties, including swelling power, pasting characteristics, thermal transition temperatures in the differential scanning calorimeter, and in susceptibility to invitro attack by α-amylase. The results indicate the importance of structural characteristics of starch molecules, particularly amylopectin, as determinants of the properties of native starch granules.     

Analysis of the cultivable bacterial community in jeotgal, a Korean salted and fermented seafood, and identification of its dominant bacteria

Jeotgal or jeot, a traditional Korean salted and fermented food, is made by adding 20-30% (w/w) salt to various types of seafood. To develop a more complete overview of the bacterial community present in jeotgal, 610 pure colonies were isolated from Myeolchi-jeot and Saeu-jeot, the most commonly consumed varieties of jeotgal, which are made with anchovy (Engraulis japonicas) and tiny shrimp (Acetes japonicas), respectively. The bacterial isolates were identified by 16S rDNA sequence analysis. A total of 104 species comprising 47 genera and 31 previously unknown species were identified. Eleven genera were isolated from both jeotgal samples, including species in the genera Staphylococcus, Bacillus, Halomonas, and Kocuria, with Staphylococcus spp. constituting the highest number. The most populous genus detected in Myeolchi-jeot was Bacillus and its relatives, while the most populous in Saeu-jeot was Staphylococcus. These were isolated from both jeotgal samples, but their proportion in the bacterial community may be influenced by matrix composition and fermentation parameters. Among the proteolytic isolates, although Virgibacillus halodenitrificans KM2100 and Staphylococcus spp. maintained their growth in 20% NaCl, protease activities were not detected in these conditions. This suggests that bacteria are not the major source of the proteolytic enzyme involved in protein hydrolysis in high-salt-containing jeotgal. However, the Staphylococcus spp. isolated from Saeu-jeot were too numerous for us to ignore their possible role in jeotgal fermentation. Staphylococcus spp. may not be hugely involved in proteolysis, but they may play a significant role in the ripening of jeotgal. Bacteria of the genus Bacillus and its relatives and of the genus Staphylococcus may be the major organisms involved in jeotgal fermentation.     

Comparison of free amino acid,carbohydrates concentrations in Korean edible and medicinal mushrooms

Ten popular species of both edible and medicinal Korean mushrooms were analysed for their free amino acids and disaccharides. The average total free amino acid concentration was 120.79 mg g⁻¹ in edible mushrooms and 61.47 mg g⁻¹ in medicinal mushrooms, respectively. The average total of free amino acids for all mushrooms, edible mushrooms and medicinal mushrooms was 91.13 mg g⁻¹. Agaricus blazei (227.00 mg g⁻¹) showed the highest concentration of total free amino acids; on the other hand, Inonotus obliquus (2.00 mg g⁻¹) showed the lowest concentration among the 10 species of mushrooms. The average total carbohydrates concentration was 46.67 mg g⁻¹ in the 10 species of mushrooms, where the edible mushrooms contained 66.68 mg g⁻¹ and the medicinal mushrooms contained 26.65 mg g⁻¹. The carbohydrates constituents of the 10 mushroom species were mainly mannose (36.23%), glucose (34.70%), and xylose (16.83%).     

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.     

Characterization of bacteriocins produced by two strains of Lactobacillus plantarum isolated from Beloura and Chouriço, traditional pork products from Portugal

Bacteriocins bacST202Ch and bacST216Ch, produced by Lactobacillus plantarum strains isolated from Beloura and Chouriço, respectively, inhibited the growth of a number of Gram-positive and Gram-negative meat spoilage bacteria. According to trycine–SDS–PAGE, bacST202Ch and bacST216Ch are approximately 3.5 and 10.0 kDa in size, respectively. Maximal activity of bacST202Ch (25,600 AU/ml) was recorded after 27 h of and bacST216Ch (102,400 AU/ml) after 22 h of growth. The mode of activity, as determined against Enterococcus faecium HKLHS, is bactericidal. Both peptides adsorb to the surface of the producer cells, but at very low concentrations. Both peptides remained active after 120 min at 100 ^oC and after 2 h of incubation at pH 2.0–12.0. Treatment for 120 min at 121 ^oC did not affect bacST216Ch activity. Activity of bacST202Ch and bacST216Ch was not affected by 1% Triton X-100, Tween 80, Tween 20, SDS, NaCl, urea and EDTA. Bacteriocin ST216Ch was deactivated in the presence of 1% Triton X-114. The nucleotide sequence of a 1044 bp DNA fragment amplified from L. plantarum ST202Ch is identical to the structural gene encoding pediocin PA-1, suggesting that the two bacteriocins are identical. Based on the broad spectrum of antibacterial activity, strains ST202Ch and ST216Ch may be used as starter cultures in the fermentation of meat products.     

Phytochemical composition and in vitro antimicrobial and antioxidant activities of some medicinal plants

Different parts of three plants (Primula auriculata, Fumaria vaillantii and Falcaria vulgaris) were extracted with three different solvents to yield 72 crude extracts. The phytochemical analysis (chemical screening, GC–MS) of three plants was investigated for their antioxidant and antibacterial activity using nine Gram-positive and Gram-negative bacteria. The principal antioxidant and antimicrobial components were determined using HPLC with UV detection. All extracts possessed antibacterial activity especially methanolic extracts from flowers of P. auriculata. The DPPH-radical scavenging assay exhibited high antioxidant activities in three plants (more than 80% at 50 μg). The F. vulgaris showed high content of carvacrol (29.8%) as main component. The contents of carvacrol and fumaric acid in the methanolic–water extracts were 1119 and 1966 mg/l respectively. Our results indicate that these plants would be able to promise sources of natural products with potential antibacterial and antioxidant activity.