Polyphenol oxidase properties,anti-urease,and anti-acetylcholinesterase activity of Diospyros lotus L. (Plum Persimmon)

Diospyros lotus fruit polyphenol oxidase was purified using affinity chromatography, resulting in a 15-fold enrichment in specific activity. The purified enzyme, having 16.5 kDa molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, exhibited the highest activity toward 4-methylcatechol. Maximum diphenolase activity was reached at pH 7.0 and 60°C in the presence of 4-methylcatechol. K_m and V_max values were calculated as 3.8 mM and 1250 U/mg protein, respectively. Ascorbic acid was a promising inhibitor with an IC₅₀ value of 0.121 µM. The activity of the purified enzyme was stimulated by Fe²⁺, Sr²⁺, Zn²⁺, and K⁺ and deeply inhibited by Hg²⁺, at 1 mM final concentration. Aqueous extract of Diospyros lotus L. fruit showed strong substantial urease and acetylcholinesterase inhibition, with IC₅₀ values of 1.55 ± 0.05 and 16.75 ± 0.11 mg/mL, respectively.     

Characterization of the recombinant succinic semi‐aldehyde dehydrogenase from Saccharomyces cerevisiae

The yeast succinic semi‐aldehyde dehydrogenase gene (SSADH; EC 1.2.1.16) was cloned and overexpressed in Escherichia coli. Based on SDS–PAGE, the molecular mass of the subunit was around 54 kDa, and the purified recombinant enzyme had a tetrameric molecular mass of ca. 200 kDa. The specific activity of the recombinant enzyme was 1.90 µm NADH formed/min/mg, and showed maximal activity at pH 8.4. The recombinant protein was highly specific for succinate semi‐aldehyde (K_m = 15.48 ± 0.14 µm ) and could use both NAD⁺ and NADP⁺ as co‐factors, with K_m values of 579.06 ± 30.1 µm and 1.017 ± 0.46 mm, respectively. Initial velocity studies showed that NADH was a competitive inhibitor with respect to NAD⁺ (K_i = 129.5 µm ) but a non‐competitive inhibitor with respect to succinate semi‐aldehyde. Adenine nucleotides of AMP, ADP and ATP inhibited yeast SSADH activity with K_i = 1.13–10.2 mm, and showed competitive inhibition with respect to NAD⁺ and mixed‐competitive, non‐competitive and non‐competitive inhibition, respectively, with respect to succinate semi‐aldehyde. The kinetic data suggest a 'ping‐pong' mechanism. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of probiotic lactobacilli on faecal enzyme and genotoxic activity in human faecal water in the presence of the carcinogen PhIP in vitro

The average β‐glucuronidase activity for children was 0.48 ± 0.04 U/mg, for adults 0.75 ± 0.27 U/mg and for elderly 1.55 ± 0.06 U/mg. For β‐glucosidase, it was 0.19 ± 0.02 U/mg for children, 0.77 ± 0.26 U/mg for adults and 1.18 ± 0.27 U/mg for elderly. In the presence of probiotics, the highest decrease in genotoxicity was observed for Lactobacillus casei 0908 (to 7.99 ± 1.32) and Lactobacillus paracasei 0919 (to 6.19 ± 1.44) for all children. In adults, lower mean genotoxicity was regarded after incubation of PhIP with L. casei 0908 (it was 5.27 ± 1.13) and L. paracasei 0919 (it was o 6.01 ± 1.00). For elderly, statistically significant decrease was maintained after incubation of PhIP with L. casei 0900 (to 6.72 ± 2.67).     

Molecular cloning,expression, and enzymatic characterization of <Emphasis Type="Italic">Solanum tuberosum</Emphasis> hydroperoxide lyase

A cDNA encoding hydroperoxide lyase (HPL) was isolated from Solanum tuberosum, cloned into pQE-30 vector, and expressed in E. coli. The recombinant protein was purified by nickel affinity chromatography and showed an approximate molecular weight of 54 kDa by SDS–PAGE analysis, which was similar to the predicted value based on the putative amino acid sequences (53.9 kDa). 13-Hydroperoxy-linolenic acid (13-HPOT) was the preferred substrate for the enzyme compared with 13-hydroperoxy-linoleic acid (13-HPOD). The corresponding volatile products were 2(E)-hexenal and n-hexanal tested by headspace-gas chromatography, respectively. The enzyme was optimally active at 25 °C and pH 6.5. The K _m, V _max, and the catalytic efficiency (V _max/K _m) for 13-HPOT were 56.6 μM, 71.3 units/mg, and 1.26 units/mg · μM, respectively. Activity of the recombinant potato HPL increased when Triton X-100, sodium chloride, or potassium chloride was added in the reaction mixture, while calcium chloride decreased activity of the recombinant enzyme.     

Antioxidant,Antibacterial, and Antiproliferative Activities of Free and Bound Phenolics from Peel and Flesh of Fuji Apple

This study was conducted to investigate the antioxidant, antibacterial, and antiproliferative activities of flesh free (FF), flesh bound (FB), peel free (PF), and peel bound (PB) phenolics from Fuji apple. The PB, which had highest total phenolic contents (126.15 ± 2.41 mg/100 g wet weight) and lowest total carbohydrate contents (34.68 ± 2.78 mg/100 g wet weight), showed the strongest 2,2’‐azinobis‐(3‐ethylbenthiazoline‐6‐sulphonate) (ABTS) radical scavenging activity (EC₅₀ = 0.36 ± 0.02 mg/mL), 1,1‐diphenyl‐2‐picryhydrazyl (DPPH) radical scavenging activity (EC₅₀ = 0.26 ± 0.01 mg/mL), and ferric reducing antioxidant power (Ferric reducing antioxidant power; EC₅₀ = 0.19 ± 0.02 mg/mL) compared with those of FF, FB, and PF. The PB also showed the strongest antibacterial activities on Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes and it also showed the highest antiproliferative effects on Caco‐2 human colonic cancer cell (EC₅₀ = 1.44 ± 0.01 mg/mL) and Hela human cervical cell (EC₅₀ = 2.81 ± 0.01 mg/mL). Both free and bound phenolics from Fuji apple showed good antioxidant, antibacterial, and antiproliferative activities in our study, and bound phenolics had significantly higher activities compared with those of free phenolics.     

Investigation of a wild pear species (Pyrus elaeagnifolia subsp. Elaeagnifolia Pallas) from Antalya,Turkey: polyphenol oxidase properties and anti-xanthine oxidase,anti-urease,and antioxidant activity

Polyphenol oxidase properties and anti-xanthine oxidase, anti-urease, and antioxidant activity were investigated in Pyrus elaeagnifolia subsp. elaeagnifolia Pallas harvested from Antalya, Turkey. Optimum pH and temperature were 7.0 and 30°C, respectively. Selected kinetic properties of polyphenol oxidase was evaluated.The K_m and V_max-values, using 4-methylcatechol as substrate, were calculated as 3.57 mM and 4781 U/mg protein, respectively. IC₅₀-values ranged from 0.0036 to 4.0231 mM against sodium metabisulphite, ascorbic acid, sodium azide, and benzoic acid, while ascorbic acid was the strongest inhibitor. Aquatic extracts of the sample exhibited strong antioxidant capacity and substantial xanthine oxidase and urease inhibition, with IC₅₀-values of 10.75 ± 0.11 and 0.97 ± 0.03 mg/mL, respectively.     

Optimisation of hydrolysis of purple sea urchin (Strongylocentrotus nudus) gonad by response surface methodology and evaluation of in vitro antioxidant activity of the hydrolysate

BACKGROUND: Hydrolysates prepared from sea urchin (Strongylocentrotus nudus) gonad by enzymatic treatment showed strong 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging activity and reducing power. RESULTS: Hydrolysis of S. nudus gonad by the commercial protease papain was optimised for maximum degree of hydrolysis (DH) and trichloroacetic acid‐soluble peptide index (TCA‐SPI) using response surface methodology. Results showed that the optimal conditions were the following: temperature of 48.83 °C, pH of 6.92, enzyme‐to‐substrate ratio of 3143 U g^?1, and substrate concentration of 83.5 g L^?1. Under these conditions, a DH of 27.96 ± 0.54% and a TCA‐SPI of 57.32 ± 0.63% were obtained. The hydrolysate prepared in the optimal conditions was fractionated by an ultra‐filtration system and the resultant fraction below 10 kDa was found to effectively scavenge hydroxyl radical (EC₅₀ = 13.29 ± 0.33 mg mL^?1) and hydrogen peroxide (EC₅₀ = 16.40 ± 0.37 mg mL^?1), inhibit lipid peroxidation (EC₅₀ = 11.05 ± 0.62 mg mL^?1), chelate Fe²⁺ (EC₅₀ = 7.26 ± 0.44 mg mL^?1), and protect mice macrophages against death induced by tert‐butyl hydroperoxide. CONCLUSION: Hydrolysates prepared from S. nudus gonad have the potential to be applied as natural antioxidant agents. Copyright © 2012 Society of Chemical Industry     

Oregano: chemical analysis and evaluation of its antimalarial, antioxidant, and cytotoxic activities

Abstract: GC‐FID and GC‐MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p‐cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC₅₀= 2 ± 0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC₅₀= 4.8 ± 0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC₅₀ of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.     

Expression and characterization of β-1,3-1,4-glucanase of Aspergillus usamii in Escherichia coli and its application in sourdough bread making

A β-1,3-1,4-glucanase gene (Auglu12A) from Aspergillus usamii was successfully expressed in Escherichia coli BL21(DE3). The recombinant enzyme, reAuglu12A was efficiently purified using the one-step nickel-nitrilotriacetic acid affinity chromatography. The specific activity of reAuglu12A was 694.8 U/mg, with an optimal temperature of 55°C and pH of 5.0. The reAuglu12A exhibited stability at temperatures up to 60°C and within the pH range of 4.0–5.5. The reAuglu12A hydrolytic activity was increased in the presence of metal ions, especially K⁺ and Na⁺, whereas it exhibited a K_m and V_max of 8.35 mg/mL and 1254.02 µmol/min/mg, respectively, toward barley β-glucan at pH 5.0 and 55°C. The addition of reAuglu12A significantly increased the specific volume (p < 0.05) and reduced crumb firmness and chewiness (p < 0.05) of wheat–barley sourdough bread during a 7-day storage period compared to the control. Overall, the quality of wheat–barley sourdough bread was improved after incorporation of reAuglu12A (especially at 3000 U/300 g). These changes were attributed to the synergistic effect of acidification by sourdough and its metabolites which provided a conducive environment for the optimal action of reAuglu12A in the degradation of β-glucans of barley flour in sourdough. This stabilized the dough structure, thereby enhancing the quality, texture, and shelf life of the bread. These findings suggest that reAuglu12A holds promise as a candidate for β-glucanase application in the baking industry.     

Characterization of L-Arabinose Isomerase in Bacillus subtilis,a GRAS Host,for the Production of Edible Tagatose

L-Arabinose isomerase (AI; E.C. 5.3.1.4), a commercial enzyme for the production of edible tagatose in vitro and ribulose production in vivo, has been studied using enzymes expressed in an Escherichia coli system, which might cause noxious by-products in food. To ensure food safety in the tagatose manufacturing process, we studied an AI expression system in Bacillus subtilis. The AI gene from Geobacillus stearothermophilus (GSAI) was expressed in Bacillus subtilis, a GRAS host used in the production of fermented soybean in Korea, after subcloning into a Bacillus subtilis - E. coli shuttle vector, and was characterized after purification. The activities of the crude enzyme extract and a purified sample were 0.15 U/mg protein and 2.7 U/mg protein, respectively. The optimal pH and the optimal temperature for arabinose and galactose as substrates were pH 8.0 and 60°C, respectively, the same as those for GSAI in an E. coli expression system. Substrate affinities (K_m) for arabinose and galactose were 77 mM and 279 mM, respectively, whereas in the E. coli expression system, they were 100 mM and 578 mM, respectively. Catalytic efficiencies (k_cat/K_m) for arabinose and galactose were 58.3 and 11.4 mM^?1 min^?1, respectively. The potential use of GSAI expressed in a GRAS host for the production of edible tagatose is discussed in light of these results.     

Pharmacokinetics of xanthohumol and metabolites in rats after oral and intravenous administration

Scope Xanthohumol (XN), a dietary flavonoid found in hops, may have health‐protective actions against cardiovascular disease and type 2 diabetes. Yet, there are limited data on the pharmacokinetics (PK) of XN. This study provides PK parameters for XN and its major metabolites in rats. Methods and results A PK study was conducted in male jugular vein‐cannulated Sprague‐Dawley rats. Rats (n = 12/group) received an intravenous (IV) injection (1.86 mg/kg BW) or an oral gavage of a low (1.86 mg/kg BW), medium (5.64 mg/kg BW), or high (16.9 mg/kg BW) dose of XN. Plasma samples were analyzed for XN and its metabolites using LC‐MS/MS. The maximum concentration (C_max) and area under the curve (AUC_{0‐96 h}) of total XN (free and conjugated) were 2.9±0.1 mg/L and 2.5±0.3 h^* mg/L in IV group, 0.019±0.002 mg/L and 0.84±0.17 h^* mg/L in the oral low group, 0.043±0.002 mg/L and 1.03±0.12 h^* mg/L in the oral medium group, and 0.15±0.01 mg/L and 2.49±0.10 h^* mg/L in the oral high group. Conclusion The bioavailability of XN is dose‐dependent and approximately 0.33, 0.13, and 0.11 in rats, for the low‐, medium‐, and high‐dose groups, respectively.     

Antioxidant and anticytokine effects of bovine colostrum in intestinal ischemia/reperfusion injured rat model

The objective of this study was to examine antioxidant and anticytokine effects of bovine colostrum (BC) in an intestinal ischemia/reperfusion injured rat model. Forty Sprague-Dawley rats were induced intestinal ischemia/reperfusion injury. After reperfusion the rats were given BC, 0.9% saline or low fat milk (LFM) orally. The antioxidative activities using superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT), and malondialdehyde (MDA) were analyzed in this study. Serum cytokine levels [tumor necrosis factor (TNF)-α, interlukin (IL)-1β, IL-6, and IL-10] were also checked. SOD (1.53±0.23 U/mg of protein), GSH-PX (7.62±0.66 U/mg of protein), and CAT (42.16±3.16 U/mg of protein) activities increased and MDA level (0.58±0.05 mmol/mg of protein) decreased significantly in rats fed BC compared to rats fed saline or LFM (p<0.05). TNF-α (7.63±1.31 pg/mL), IL-1β (49.43±4.43 pg/mL), and IL-6 (62.85±7.60 pg/mL) in rats fed BC were significantly lower than saline or LFM (p<0.005), whereas there was no significant difference in IL-10 (220.3±22.06 pg/mL) between experimental groups. In conclusion, BC may have both antioxidative and anticytokine effects in an intestinal ischemia/reperfusion rat model.     

Health-promoting effects of dietary polysaccharide extracted from Dendrobium aphyllum on mice colon,including microbiota and immune modulation

The health-promoting effects of a polysaccharide (DAP) purified from Dendrobium aphyllum, on mice colon were investigated. The results indicated that consumption of DAP facilitated the differentiation degree of CD4⁺ T cells to Th₁, Th₁₇ and Treg cells; and depressed the differentiation degree to Th₂ cells, since DAP up-regulated IL-6 expression (from 1.08 ± 0.24 to 3.40 ± 0.36). Besides, oral administration of DAP reduced the gastrointestinal transit time from 255 ± 1.21 to 164 ± 0.46 min, decreased the pH from 6.70 ± 0.27 to 5.54 ± 0.31, improved faecal water-binding capability from 59.4% ± 0.35 to 63.5% ± 0.22. Additionally, the increase in four health-promoting short chain fatty acids were observed, which might result from the enrichment of the relative abundance of health-promoting microbiota genera, including Porphyromonadaceae and Ruminococcaceae. The DAP-induced up-regulation of the genus Erysipelotrichaceae might be related to the homeostasis in both Th₁/Th₂ and Treg/Th₁₇.     

Phenolic composition,antioxidant, antibacterial,larvacidal against Culex pipiens,and cytotoxic activities of Hyacinthella lineata steudel extracts

This study reports the phenolic composition, antioxidant, antibacterial, larvacidal, and cytotoxic activity of methanol and acetone extracts of Hyacinthella lineata leaves and bulbs. The phenolic composition of H. lineata was determined by HPLC. The most abundant component was gallic acid (421.9µg/g). The β-carotene/DPPH/ABTS/FRAP decoloration method was used to estimate the total antioxidant activity. The total antioxidant activity was the highest for bulb-methanol fraction (65.41 ± 0.05%). The total phenolic content for leaves-methanol extract of the plant was determined as 6.56 ± 4.027mg/mL gallic acid equivalents. Analysis of the antibacterial activity showed that the methanolic-bulb extract are efficient against gram positive and gram negative bacteria. The cytotoxic effect on Artemia salina was assessed by Brine shrimp assay. Brine shrimp lethality assay showed that LC₅₀ values of HBM were obtained as 4.105 ± 2.42μg/ml. The bulb extract of H. lineata showed the highest larvicidal activity against Cx pipiens with value LC₅₀ (64.3275μg/ml). This study suggested that H. lineata may be used as a potential source of antioxidant, and for their biological activity, cytotoxic and antimicrobial properties.     

Purification,Identification, and In Vivo Activity of Angiotensin I‐Converting Enzyme Inhibitory Peptide,from Ribbonfish (Trichiurus haumela) Backbone

Ribbonfish (Trichiurus haumela) backbone is normally discarded as an industrial waste from fish processing. A method of developing angiotensin I‐converting enzyme inhibitory (ACEI) peptides from ribbonfish backbone was previously optimized. The purposes of the study were to characterize the active peptides in the hydrolysate and to evaluate its in vivo activity. Ribbonfish backbone protein hydrolysate prepared by acid protease was fractionated into 4 fractions (I, MW < 1 kDa; II, MW = 1 to 5 kDa; III, MW = 5 to 10 kDa; and IV, MW > 10 kDa) through ultrafiltration membranes. Fraction I, showing the highest ACEI activity, was further purified using consecutive chromatographic techniques including gel filtration and reversed phase high‐performance liquid chromatography. The purified ACE inhibitory peptide was determined to have a molecular weight of 317.25 Da, with a sequence of Leu‐Trp and an IC₅₀ value of 5.6 μM. Systolic blood pressure of spontaneously hypertensive rats was significantly decreased from 181 ± 2.0 to 161.3 ± 2.3 mm Hg after 4 h of oral administration of Leu‐Trp at a dose of 10 mg/kg of body weight. These results indicated that ribbonfish backbone protein could be used for development of antihypertensive agent.     

Occurrence of the C-series fumonisins in maize from the former Transkei region of South Africa

Fumonisins are a group of structurally related mycotoxins produced mainly in maize by Fusarium verticillioides and F. proliferatum. The most abundant naturally occurring analogue is fumonisin B₁ (FB₁), with lesser amounts of fumonisin B₂ (FB₂) and fumonisin B₃ (FB₃) occurring. The C-series fumonisins (FCs) are structurally analogous to the B-series but lack the C-1 methyl group. Good and mouldy subsistence-grown maize samples were collected from the Centane and Bizana districts in the former Transkei region of South Africa. After extraction with methanol/water and clean-up on strong anion exchange solid phase extraction cartridges, FB₁, FB₂, FB₃, FC₁, FC₃ and FC₄ were determined by reversed-phase LC–MS/MS using positive ion electrospray ionisation. FB₁ levels in both good and mouldy maize from Centane (means (±SD) 2.75?±?2.24 and 23.4?±?12.5?mg?kg^?1, respectively) were higher than the corresponding levels in maize samples from Bizana (means 0.056?±?0.157 and 3.71?±?5.01?mg?kg^?1, respectively). Similarly, FC₁ levels in both good and mouldy maize from Centane (means 0.107?±?0.099 and 0.814?±?0.391?mg?kg^?1, respectively) were higher than in Bizana, where FC₁ was detected in only one (0.018?mg?kg^?1) of 19 good maize samples and occurred in mouldy maize with a mean of 0.102?±?0.135?mg?kg^?1. A significant correlation (r?=?0.982, p?<?0.01) was observed between FB₁ and FC₁ levels in all samples, with FC₁ levels at 3.3% of the corresponding FB₁ levels. FC₄ levels were similar to FC₁, whereas only low amounts of FC₃ were detected.     

Purification of New β-Galactosidase from Enterococcus faecium MTCC 5153 with Transgalactosylation Activity

A new β-galactosidase (β-gal) was purified from a lactic acid bacterial strain of Enterococcus faecium MTCC5153 by chromatographic techniques. The purified enzyme had a specific activity of 24.06 U/mg of protein with k _m and V_max values of 2 mM and 18.2 mM/min/mg of protein, respectively. The yield of purified β-gal was 10.65% and estimated molecular weight found to be ～90 kDa, consisting of two homodimeric subunits of 43kDa. The enzyme was stable in pH range of 8.0–9.0 with an optimum pH of 8 and the optimum temperature of 40°C. The enzyme was activated in the presence of metal ions such as Mg⁺², Mn⁺², Ca⁺², K⁺ and Na⁺ and was inhibited by Zn⁺², Co⁺² and Cu⁺². Chemical modifiers (N-bromosuccinamide and Diethylpyro carbonate) inactivated the enzyme indicating the role of tryptophan and histidine moieties for activity. The purified β-gal was able to synthesize oligosaccharides from lactose. This study suggests that the β-gal of Enterococcus faecium MTCC5153 could be applied in dairy industry for hydrolysis of lactose and to improve its digestibility. β-gal of probiotic cultures are of particular interest due to their transgalactosylation properties.     

The yeast enzyme Eht1 is an octanoyl‐CoA:ethanol acyltransferase that also functions as a thioesterase

Fatty acid ethyl esters are secondary metabolites that are produced during microbial fermentation, in fruiting plants and in higher organisms during ethanol stress. In particular, volatile medium‐chain fatty acid ethyl esters are important flavour compounds that impart desirable fruit aromas to fermented beverages, including beer and wine. The biochemical synthesis of medium‐chain fatty acid ethyl esters is poorly understood but likely involves acyl‐CoA:ethanol O‐acyltransferases. Here, we characterize the enzyme ethanol hexanoyl transferase 1 (Eht1) from the brewer's yeast Saccharomyces cerevisiae. Full‐length Eht1 was successfully overexpressed from a recombinant yeast plasmid and purified at the milligram scale after detergent solubilization of sedimenting membranes. Recombinant Eht1 was functional as an acyltransferase and, unexpectedly, was optimally active toward octanoyl‐CoA, with k_cat = 0.28 ± 0.02/s and K_M = 1.9 ± 0.6 μm . Eht1 was also revealed to be active as a thioesterase but was not able to hydrolyse p‐nitrophenyl acyl esters, in contrast to the findings of a previous study. Low‐resolution structural data and site‐directed mutagenesis provide experimental support for a predicted α/β‐hydrolase domain featuring a Ser–Asp–His catalytic triad. The S. cerevisiae gene YBR177C/EHT1 should thus be reannotated as coding for an octanoyl‐CoA:ethanol acyltransferase that can also function as a thioesterase. © 2014 The Authors. Yeast published by John Wiley & Sons, Ltd.     

Amaranth Sprouts: A Potential Health Promoting and Nutritive Natural Food

Amaranth sprouts are an edible food with good nutritional qualities and potential biological activities of their proteins. The chemical composition, angiotensin converting enzyme inhibitory activity and antioxidant activity of the sprouts were determined. Sprouts showed a protein content similar to the seeds’ on a dry basis (16%) and a high fiber content (17%). Amaranth sprout proteins presented a capacity to inhibit angiotensin converting enzyme activity similar to other plant proteins (IC₅₀ = 0.9 ± 0.6 mg/mL). This capacity increased after in vitro gastrointestinal digestion (IC₅₀ = 0.26 ± 0.07 mg/mL). Besides other non protein molecules, the amaranth sprout proteins also presented ABTS^+. scavenging activity (TEAC = 0.32 ± 0.05 μmol/mg) that increased after in vitro gastrointestinal digestion (TEAC = 0.72 ± 0.08 μmol/mg) and oxygen radical antioxidant capacity. According to these results amaranth sprouts are a nutritive food with potential health promoting properties.     

Purification, characterization, and production of β-mannanase from Bacillus subtilis TJ-102 and its application in gluco-mannooligosaccharides preparation

A novel β-mannanase-producing strain, Bacillus subtilis TJ-102, was identified and characterized. Response surface method was applied to improving and enhancing the enzyme production. The optimized media components were obtained: 45.25 g/L konjac, 9.29 g/L Na₂HPO₄·12H₂O, 2.60 g/L CaCO₃, 1.0 g/L (NH₄)₂SO₄, 0.3 g/L KH₂PO₄, 1.0 g/L NaCl, 1.0 g/L MgCl₂·6H₂O, and 0.01 g/L FeSO₄. Under these conditions, the β-mannanase activity could achieve 205.3 U/mL in a 7-L fermentor. Then, β-mannanase was 7.39-fold purified by salting out, ultrafiltration, anion-exchange, and size-exclusion preparative chromatography with a recovery of 21.41 % and a specificity of 125.36 U/mg proteins. β-Mannanase was stable below 65 °C and pH 5.0–8.0, which exhibited excellently enzymatic efficiency in the preparation of gluco-mannooligosaccharides (GMOS) by hydrolyzing konjac flour. The GMOS yield of 57.76 % has been achieved with 8.71 % of mannose and 14.49 % of glucose, demonstrating the potential use of β-mannanase in food industry.