Fatty acid composition of four potential aquatic weeds and their possible use as fish-feed neutraceuticals

A study was conducted to explore the fatty acid composition of four aquatic weeds, namely Salvinia cuculata, Trapa natans, Lemna minor and Ipomoea reptans collected from water bodies of Assam, India. It has been observed that C24:1 (Cis-15 Tetracosenoic acid) followed by C16:1 n-3 (9-Hexadecenoic acid) are the predominant fatty acids in these aquatic weeds and among them, Ipomoea reptans and Trapa natans contain higher proportions of C18:2 and C18:3 PUFA. The ratio of saturated fatty acid to unsaturated fatty acid is extremely low in the case of all four plants and they contain a predominant proportion of highly unsaturated fatty acids (HUFA), essential for the growth and proper performance of fish.     

Non-volatile taste components of Agaricus blazei, Agrocybe cylindracea and Boletus edulis

Three species of dried mushrooms are commercially available in Taiwan, namely Agaricus blazei (Brazilian mushroom), Agrocybe cylindracea (black popular mushroom) and Boletus edulis (king bolete), and their non-volatile taste components were studied. All mushrooms were high in contents of carbohydrate, crude fiber and protein but low in contents of crude ash and fat. Arabitol, myo-inositol, mannitol and trehalose were detected in these three mushrooms, whereas glucose was not found in B. edulis. Contents of total soluble sugars and polyols ranged from 150.33 to 225.08 mg/g. Total free amino acid contents were low in these three mushrooms and ranged from 8.97 to 14.91 mg/g. The contents of MSG-like components ranged from 1.24 to 4.40 mg/g were in the descending order of the A. blazei, A. cylindracea and B. edulis. Total 5′-nucleotides contents of A. blazei and A. cylindracea were higher than that of B. edulis whereas flavor 5′-nucleotides content of A. blazei was higher than those of A. cylindracea and B. edulis. Equivalent umami concentrations values in three mushrooms ranged from 10.46 to 135.90 g per 100 g. Overall, these three mushrooms possessed highly umami taste.     

Nonvolatile taste components of Grifola frondosa, Morchella esculenta and Termitomyces albuminosus mycelia

Three species of mushroom mycelia are commercially available in Taiwan, namely Grifola frondosa (maitake), Morchella esculenta (morel), and Termitomyces albuminosus (termite mushroom), and their nonvolatile taste components were studied. All mycelia were high in contents of carbohydrate, crude fat and protein but low in contents of crude ash and fiber. Arabitol, glucose, mannitol and trehalose were detected in these three mycelia and total amounts of sugars and polyols were 63.69-83.89 mg/g. Total free amino acid contents in three mycelia ranged from 35.67 to 50.37 mg/g. The monosodium glutamate-like components of G. frondosa mycelia (6.51 mg/g) was approximately twofold higher than M. esculenta and T. albuminosus mycelia (3.58 and 3.11 mg/g, respectively). As compared with other components, sweet and bitter components were much higher in these three mycelia. Contents of total 5′-nucleotides in these three mycelia ranged from 13.32 to 26.19 mg/g and were in the descending order of T. albuminosus>M. esculenta>G. frondosa. Equivalent umami concentration of T. albuminosus mycelia was higher than those of G. frondosa and M. esculenta mycelia. Overall, three mycelia possessed highly intense umami taste.     

Indole compounds in fruiting bodies of some edible Basidiomycota species

The contents of nonhallucinogenic indole compounds were determined in methanol extracts from fruiting bodies of four common edible European species of higher fungi representing the most popular taxon Basidiomycota: Agaricus bisporus (J.E. Lange), Cantharellus cibarius Fr., Lactarius deliciosus (L. Fr.) S.F. Gray and Leccinum rufum (Schaef.) Kreisel. Amongst eleven compounds under analysis, 6–7 metabolites, distinct in different species, were identified in the extracts of fruiting bodies. Serotonin and melatonin were the only common compounds to all species. The contents of the analyzed compounds were diverse, ranging from 0.01 to almost 40 mg/100 g d.w. The contents of tryptophan, 5-hydroxytryptophan, tryptamine and melatonin were low (below 1.40 mg/100 g d.w.). Noteworthy, the serotonin contents were very high in all species under study and amounted to 5.21, 29.61, 18.42 and 31.71 mg/100 g d.w., respectively. Moreover, the fruiting bodies of these species contained indoleacetic acid (max. 2.04 mg/100 g d.w.) and tryptophan degradation products: kynureine sulfate (max. 39.20 mg/100 g d.w.) and kynurenic acid (6.21 mg/100 g d.w.).     

Nutritional and in vitro antioxidant properties of edible wild greens in Iberian Peninsula traditional diet

Wild greens are nutritionally well-balanced vegetables. Herein, nutritional and in vitro antioxidant properties of the sprouts of three commonly used species were determined. Wild asparagus revealed the highest levels of moisture (84.6 g/100 g fw), ash (12.3 g/100 g dw), proteins (22.4 g/100 g dw), total sugars (9.24 g/100 g dw), including sucrose (4.27 g/100 g dw), and of the essential n-6 fatty acid linoleic acid (44.5%); white bryony gave the highest contents of reducing sugars, including glucose (2.97 g/100 g dw), essential n-3 fatty acid α-linolenic acid (70.3%), and the best ratios of PUFA/SFA, and n-6/n-3 fatty acids (3.59 and 0.0907, respectively); black bryony showed the highest concentrations of carbohydrates (69.3 g/100 g dw), fructose and trehalose (3.83 and 1.34 g/100 g dw, respectively). Besides their culinary characteristics, their high content in vitamins (asparagus, 135 and 142 mg/100 g dw of total tocopherols and ascorbic acid, respectively), chlorophylls (white bryony, 50.9 mg/100 g dw), carotenoids (23.3 mg/100 g dw) and phenolics (black bryony, 759 mg GAE/g extract), together with the antioxidant properties (EC₅₀ values lower than 640 μg/ml) and potential health benefits increase their importance in traditional as well as in contemporary diets.     

Histamine formation by histamine-forming bacteria and yeast in mustard pickle products in Taiwan

The occurrence of histamine, histamine-forming bacteria and yeast were tested in 37 mustard pickle products sold in both retail markets and supermarkets in southern Taiwan. Aerobic plate count (APC), total coliform, and Escherichia coli were also tested for microbiological quality. Salt content, pH value, titratable acidity and sulphite content were determined for quality of mustard pickle products. Only one retail market sample and one supermarket sample had 8.9 and 7.4 mg histamine per 100 g products, although the average content for each of the nine biogenic amines was less than 2 mg/100 g. Ten histamine-forming bacterial strains and 6 histamine-producing yeast strains capable of producing 8.7 to 1260 ppm of histamine in trypticase soy broth (TSB) supplemented with 1% l-histidine (TSBH) were identified as Staphylococcus capitis (four strains),Staphylococcus pasteuri (two strains), Enterobacter cloacae (four strains), Candida glabrata (two strains) and Candida rugosa (four strains). S. capitis, which was previously reported to be halotolerant, was a potent histamine-former, capable of producing more than 1000 ppm of histamine in TSBH in the presence of 0.5–10% NaCl. The numbers of the aerobic plate count (APC) in all samples were below the Taiwanese regulatory level of 5 log CFU/g. None of the samples contained total coliform or E. coli. The values of pH, salt content, titratable acidity and sulphite content in all samples ranged from 3.8% to 5.0%, 2.0% to 10.0%, 0.21% to 1.18% and <2.0–1876 ppm, respectively.     

Histamine formation by histamine-forming bacteria in douchi,a Chinese traditional fermented soybean product

Seven soybean and 19 black bean douchi products sold in the supermarkets in southern Taiwan were purchased and tested to determine the occurrence of histamine and histamine-forming bacteria. The levels of pH, salt content, water content, yeast and mold, and aerobic plate count (APC) in all samples ranged from 4.7 to 5.9, 4.4% to 14.0%, 6.8% to 51.6%, 3.0 to 5.1 log CFU/g, and 5.2 to 9.2 log CFU/g, respectively. None of these samples contained total coliform and Escherichia coli. Although black bean douchi products had an average histamine content of 29.0 mg/100 g, 18 of them had histamine contents greater than 5 mg/100 g, the allowable level set by the US Food and Drug Administration (FDA) for scombroid fish and/or products. In contrast, only four soybean douchi products had histamine levels greater than 5 mg/100 g. Among the black bean samples, four contained histamine at 56.3, 62.1, 80.2 and 80.8 mg/100 g, that are above the 50 mg/100 g hazard action level. Eight histamine-forming bacterial strains, capable of producing 11.7–601 ppm of histamine in trypticase soy broth (TSB) supplemented with 1% l-histidine (TSBH), were identified as Bacillus subtilis (four strains) Staphylococcus pasteuri (one strain) and Staphylocuccus capitis (three strains) by 16S rDNA sequencing with PCR amplification. S. capitis, which was previously reported to be halotolerant, was a potent histamine-former capable of producing more than 500 ppm of histamine in TSBH in the presence of 0.5–10% NaCl.     

Assessment of in vitro antioxidant capacity and polyphenolic composition of selected medicinal herbs from Leguminosae family in Peninsular Malaysia

Determination of total phenolic (TPC), flavonoid and anthocyanin contents, and various antioxidant activities (2,2-diphenyl-1-picrylhydrazyl radical scavenging, ferric reducing power, ferrous ion chelating and lipid peroxidation inhibition) of leaves and flowers of Bauhinia kockiana, Caesalpinia pulcherrima and Cassia surattensis were performed in this study. The B. kockiana flower was found to possess the highest TPC (8280 ± 498 mg GAE/100 g), free radical scavenging activity (ascorbic acid equivalents 14,600 ± 2360 mg AA/100 g) and reducing ability (72.4 ± 8.7 mg GAE/g). Rutin and chlorogenic acid were detected in the plants, where the C. pulcherrima leaf contained the highest amount of rutin (669 ± 26 mg/100 g), while minute amounts of chlorogenic acid were detected in C. surattensis leaf (9.13 ± 0.44 mg/100 g). The C. pulcherrima leaf displayed the highest ferrous ion chelating and lipid peroxidation inhibition activities. Positive correlation was observed between TPC and various antioxidant activities.     

Physicochemical properties and tenderness of meat samples using proteolytic extract from Calotropis procera latex

This study was conducted in order to tenderise muscle foods (pork, beef and chicken) by using crude enzyme extract from Calotropis procera latex. Chunks of knuckle muscle from pork and beef as well as of breast muscle from chicken were marinated with distiled water (control) and 0.05%, 0.1%, 0.2%, 0.3% and 0.5% (w/w) of crude enzyme extract powder for 60 min at 4 °C. The marinated samples were then subjected to various physical and chemical property determinations. A decrease in moisture content was observed when the crude enzyme extract was added. Firmness and toughness of the muscle samples significantly decreased with the increased addition of crude enzyme extract (p < 0.05). The water holding capacity and cooking yield of the treated samples showed no significant difference throughout the crude enzyme extract addition (p > 0.05). Crude enzyme extract had no effect on the pH of the pork sample, but it slightly increased the pH in the beef and chicken. An increase in protein solubility and TCA-soluble peptides content was observed in all of the treated samples. The electrophoresis pattern of the muscle treated samples also revealed extensive proteolysis occurring in each muscle type. From the results, it is determined that latex from Calotropis procera can be used as an alternative source of proteolytic enzymes for the effective tenderising of meat.     

Chemical characterization of Chinese chive seed (Allium tuberosum Rottl.)

Chinese chive seeds (Allium tuberosum Rottl.) (grown in China) were investigated. Density, thousand-grain weight, and hectolitre weight of seeds were 1.27 g/cm³, 4.9 g, and 71 kg/100 l, respectively. The results showed that Chinese chive seeds contained high amounts of oil (15.8%), dietary fibre (18.2%) and crude protein (12.3%). Oil of seeds was composed of 10.1% saturated and 90.0% unsaturated fatty acids. Linoleic(69.1%) and palmitic (7.0%) were the most abundant unsaturated and saturated fatty acids, respectively. Chinese chive seeds contained 4.5 mg/kg of thiamin, 2.8 mg/kg of riboflavin and 55.1 mg/kg of niacin. The mineral contents of the seed of A. tuberosum, for iron, calcium and zinc, were 580 mg/kg, 1328 and 80.8 mg/kg, respectively. Analysis of the amino acid content of Chinese chive seed revealed that it was a rich source of the essential amino acids, isoleucine, tryptophan and lysine. The study revealed that Chinese chive seeds had high levels of nutritionally important components, such as oil, minerals and essential amino acids.     

Histamine contents of salted seafood products in Taiwan and isolation of halotolerant histamine-forming bacteria

Fifty-seven salted seafood products sold in the fishing village stores in Taiwan, including salted fish product, salted mollusc product and salted shrimp product, were tested to determine the occurrence of histamine and histamine-forming bacteria. Although the average content of each of nine different biogenic amines in all samples was less than 5.0 mg/100 g, 10.5% (6/57) of tested samples had the histamine content greater than the 5.0 mg/100 g allowable limit suggested by the US Food and Drug Administration. One histamine-producing bacterial strain, capable of producing 78.5 ppm of histamine in trypticase soy broth supplemented with 1.0% l-histidine (TSBH), was identified as Bacillus megaterium. The B. megaterium isolate was a halotolerant bacterium which grew well to an elevated NaCl concentration of 15% in TSBH medium. Besides, it had a consistent ability to produce >300 ppm of histamine at 10% NaCl concentration in TSBH medium after 72 h.     

Raw Millefiori honey is packed full of antioxidants

Total polyphenols, flavonoids and antioxidant power of raw honey samples from two of the most common Italian varieties, i.e., Millefiori and Acacia, were evaluated. Phenolic content, expressed as caffeic acid equivalents, ranged from 12.5 to 17.5 mg/100 g and from 3 to 11 mg/100 g in Millefiori and Acacia honeys, respectively. All Millefiori samples exhibited the highest flavonoid concentration being between 1.23 and 2.93 mg catechin equivalents (CE)/100 g honey. Total flavonoids in 100 g Acacia honeys were in the range of 0.45–1.01 mg CE. Acacia honeys had lower total antioxidant power, as assessed by ferric reducing/antioxidant power assay, than Millefiori. The relationship between phenolic content and antioxidant power was discussed. Comparative experimental analysis was performed with an artificial honey and processed honeys. Raw Millefiori honey is rich in both amount and variety of antioxidant substances, and its inclusion in the diet may be recommended to complement other polyphenol sources.     

Salmonella surveillance and control at post-harvest in the Belgian pork meat chain

Salmonella remains the primary cause of reported bacterial food borne disease outbreaks in Belgium. Pork and pork products are recognized as one of the major sources of human salmonellosis. In contrast with the primary production and slaughterhouse phases of the pork meat production chain, only a few studies have focussed on the post-harvest stages. The goal of this study was to evaluate Salmonella and Escherichia coli contamination at the Belgian post-harvest stages. E. coli counts were estimated in order to evaluate the levels of faecal contamination. The results of bacteriological analysis from seven cutting plants, four meat-mincing plants and the four largest Belgian retailers were collected from official and self-monitoring controls. The prevalence of Salmonella in the cutting plants and meat-mincing plants ranged from 0% to 50%. The most frequently isolated serotype was Salmonella typhimurium. The prevalence in minced meat at retail level ranged from 0.3% to 4.3%. The levels of Salmonella contamination estimated from semi-quantitative analysis of data relating to carcasses, cuts of meat and minced meat were equal to −3.40 ± 2.04 log CFU/cm², −2.64 ± 1.76 log CFU/g and −2.35 ± 1.09 log CFU/g, respectively. The E. coli results in meat cuts and minced meat ranged from 0.21 ± 0.50 to 1.23 ± 0.89 log CFU/g and from 1.33 ± 0.58 to 2.78 ± 0.43 log CFU/g, respectively. The results showed that faecal contamination still needs to be reduced, especially in specific individual plants.     

Antioxidant activity of three edible seaweeds from two areas in South East Asia

Total phenolic content (TPC) and antioxidant activity (AOA) of 50% aqueous methanol extracts of the marine algae, Padina antillarum, Caulerpa racemosa and Kappaphycus alvarezzi were studied. TPC was measured using Folin-Ciocalteu method while 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), ferrous ion chelating (FIC) assay and beta carotene bleaching (BCB) assay were used to study their AOA. P. antillarum was found to have the highest TPC, 2430±208 mg gallic acid equivalents (GAE) per 100 g dried sample and ascorbic acid equivalent antioxidant capacity (AEAC), 1140±85 mg AA/100 g. C. racemosa and K. alvarezzi displayed lower TPC and AEAC. C. racemosa had 144±22 mg GAE/100 g dried sample of TPC and 14.3±2.0 mg AA/100 g of AEAC, while K. alvarezzi had 115±35 mg/100 g dried sample of TPC and 37.8±16.8 mg AA/100 g of AEAC. In addition, P. antillarum displayed the highest reducing power, 15.7±2.6 mg GAE/g and highest chelating ability. C. racemosa and K. alvarezzi exhibited lower reducing power, 0.737±0.423 mg GAE/g and 0.561±0.269 mg GAE/g, and lower chelating ability. However, the AOA of these three seaweeds as assessed by BCB assay were equally high.     

Preparative isolation of triterpenoids from Ganoderma lucidum by counter-current chromatography combined with pH-zone-refining

Ganoderma lucidum is a famous fungus. The triterpenoids are the main bioactive components and exhibit various pharmacological activities. However, the scarcity of the pure triterpenoid has greatly restrained the modern research of G. lucidum. The present paper first describes a convenient method to separate the main triterpenoids from G. lucidum using counter-current chromatography (CCC) technique. Ganoderic acid C6 (38 mg), E (76 mg), F (32 mg) were successfully separated from the crude extract in 1 day with the HPLC purity of above 90% using stepwise CCC. Ganoderic acid G (36 mg), A (64 mg), B (25 mg), D (28 mg) and ganoderenic acid D (11 mg) were separated in 2 days with the HPLC purity of above 90% using a combination of stepwise CCC and pH-zone-refining CCC. The method presented in the paper is much quicker and easier than the previous methods.     

Compositional and nutritional evaluation of several lupin seeds

Lupin seeds of different species representing diverse varieties of sweet lupin grown in Poland were investigated. The chemical compositions of lupin isolates and amino acid composition of the proteins, as well as the nutritive values were estimated. No significant differences (P ? 0.05) were observed among lupin isolates in their dry matter, crude fibre or alkaloid contents. The highest protein content (465 ± 11 g/kg d.m.) was found in seeds from lupins belonging to Lupinus luteus (P ? 0.01), while the highest oil content (ca. 115 g/kg d.m.) was found in Lupinus albus (P ? 0.05).     

Histamine contents of fermented fish products in Taiwan and isolation of histamine-forming bacteria

Twenty-seven imported fermented fish products from Southeast Asian countries and sold in the supermarkets in Taiwan, including fish sauce, fish paste and shrimp paste, were tested to determine the occurrence of histamine and histamine-forming bacteria. The levels of pH, salt content, total volatile basic nitrogen, trimethylamine, and aerobic plate count in all samples ranged from 4.8% to 6.5%, 16.2% to 45.3%, 51 to 275 mg/100 g, 5.4 to 53.9 mg/100 g and 1.0 to 4.2 log CFU/g, respectively. The average content for each of eight different biogenic amines in all samples was less than 90 ppm, except for histamine which has an average content of 394 ppm in fish sauce, 263 ppm in fish paste, and 382 ppm in shrimp paste. Most of the tested fermented fish products (92.6%) had histamine levels greater than the FDA guideline of 50 ppm, while seven of them (25.9%) contained >500 ppm of histamine. Although Bacillus coagulans and Bacillus megaterium were identified as the two histamine-producing bacteria capable of producing 13.7 and 8.1 ppm of histamine, respectively, in trypticase soy broth broth supplemented with 1.0% l-histidine, they were not determined to be the main contributors to histamine accumulation in these fermented fish products.     

Partial purification and characterisation of endoglucanase from an edible mushroom, Lepista flaccida

A crude extract was prepared from the fruiting body of Lepista flaccida, an edible mushroom and endoglucanase activity of the extract was increased 14-fold with ammonium sulphate precipitation. Maximum enzyme activity was seen at pH 4.0 and 50 °C when carboxymethylcellulose was used as a substrate. K_0.5 and V_max values of the partially purified endoglucanase were 7.7 mg/ml and 25 ± 0.9 U/mg protein, respectively. The enzyme was quite stable over a broad range of pH (2.0–9.0) at 4 °C. When it was incubated at temperatures between 20 °C and 60 °C for 12 h, it conserved much of its original activity (over 40%). The activity of the enzyme increased by 234 ± 3.6% in the presence of 1 mM Mn²⁺. The endoglucanase was inhibited by EDTA, PMSF, β-ME and DDT. In conclusion, pH and thermal stability of the L. flaccida endoglucanase could make it useful for industrial purposes.     

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.     

Amino acid composition of three species of Nigerian fish: Clarias anguillaris,Oreochromis niloticus and Cynoglossus senegalensis

An investigation into the concentrations of amino acids in three species of Nigerian fish: Clarias anguillaris, Oreochromis niloticus and Cynoglossus senegalensis was carried out. The most abundant amino acid was Glu (108–118 mg/g crude protein) and Leu was the most abundant essential amino acid (58.0–64.7 mg/g crude protein). While total amino acid content was 618–637 mg/g crude protein, the total essential amino acid content was 300–317 mg/g or 48.6–50.0% with His but 283–299 mg/g crude protein or 45.8–47.0% without His. The limiting amino acid was Thr for C. anguillaries and C. senegalensis but Val for O. niloticus whereas Phe + Tyr scores were greater than 1.0 (1.06–1.21) in all the fish samples. Significant differences existed between the contents of essential amino acids and non-essential amino acids at p < 0.05 in all the fish samples. Percentage contents of total neutral amino acids ranged from 52.2–54.9%; for total acidic amino acids the range was 26.9–29.6% and for total basic amino acids the range was 17.7–18.2%.