The use of various live animal measurements to predict carcass and meat quality in two divergent lamb breeds

Live weight, subjective scores of condition and conformation, live animal video image analysis (LVIA), ultrasound and X-ray computed tomography (CT) scanning were used to investigate the best method or combination of methods for predicting carcass and meat quality traits in live Texel and Scottish Blackface lambs. Predictors derived from CT alone accounted for a high proportion of the variance in dissected fat and muscle weight in Texel lambs (adjusted R² = 0.8), as well as intra-muscular fat content in the loin (0.6), but lower proportions in Blackface lambs (0.7 for fat, 0.4–0.5 for muscle and intra-muscular fat), after adjusting for sire and fixed effects. Adding traits measured by other in vivo methods increased prediction accuracies (adjusted R²) by up to 0.26, depending on trait and data set. Shear force and ultimate pH could not be accurately predicted using the traits considered here (adjusted R² < 0.4). Although the same methods tended to be best for predicting product quality traits between breeds, prediction accuracies differed.     

Kinetics of phase separation during pressure-induced gelation of a whey protein isolate

The kinetic process of pressure-induced gelation of whey protein isolate (WPI) solutions (20–28%, w/v) was studied using in situ light scattering. The gelation of WPI solutions could be induced by pressurization at 250 MPa, a pressure lower than that reported in other studies. The gelation time decreased with increasing WPI concentration and followed an exponential rule. The relationship of the logarithm of scattered light intensity (I) versus time (t) was linear after the induced time and could be described by the Cahn–Hilliard linear theory. With increasing time, the scattered intensity deviated from the exponential relationship, and the time evolution of the scattered light intensity maximum I_m and the corresponding wavenumber q_m could be described in terms of the power-law relationship as I_m  t^β and q_m  t^−α, respectively. These results indicated that phase separation occurred during the gelation of WPI solutions under high pressure.     

Production of Cyclodextrins by Simultaneous Actions of Two CGTases from Three Strains of Bacillus

A moderate thermophile, which produces a large amount of extracellular and thermostable cyclomaltodextrin glucanotransferase, was isolated from soil samples at hot spring areas in Japan. The isolate (A-147), that grew at 30–60°C with an optimum at 45–50°C, was identified as a strain of Bacillus coagulans. The enzyme, which was most active at pH 6.5 and 60°C, was stabilized by 2–3 mM Ca²⁺, and degraded about 40% (as dry basis) of 13% (w/w) potato starch solution into cyclodextrins composed of α- and β-cyclodextrins dominantly at 74°C and pH 6.5 in the presence of 3 mM Ca²⁺. The ratio of α-, β- and γ-cyclodextrins was almost constant (2:2.6:1) during all stages of the reaction. By simultaneous actions of two enzymes from the bacterium and other 2 kinds of Bacillus, starch hydrolysates containing various amounts and rations of cyclodextrins were produced from starch. Ein mäßiges Thermophiles, das eine große Menge an extracellulärer und thermostabiler Glucanotransferase produziert, wurde aus Bodenproben in Heißquellengebieten von Japan isoliert. Das Isolat (A-147), das bei 30–60°C mit einem Optimum von 45–50°C wuchs, wurde als ein Stamm von Bacillus coagulans identifiziert. Das bei pH 6,5 und 60°C aktivste Enzym wurde durch 2–3 mM Ca²⁺ stabilisiert und baute etwa 40% (TS) einer 30%igen (w/w) Kartoffelstärkelösung zu Cyclodextrin ab, bestehend aus α- und β-Cyclodextrin, vorwiegend bei 74°C und pH 6,5 in Gegenwart von 3 mM Ca²⁺. Das Verhältnis von α-, β- und γ-Cyclodextrinen war nahezu konstant (2:2,6:1) während sämtlicher Reaktionsschritte. Durch gleichzeitige Einwirkung von zwei Enzymen aus dem Bakterium und zwei anderen Arten von Bacteria wurden Stärkehydrolysate hergestellt, die verschiedene Mengen und Verhältnisse an Cyclodextrinen enthielten.     

Nε-carboxymethyllysine is formed during heating of lysine with ketoses

In a model system with lysine monohydrochloride and various reducing sugars, the contents of N^ε-carboxymethyllysine (CML) were measured after heat treatment at 98°C for 3–24 h. The results show for the first time that CML could be formed by the reaction of lysine and fructose or lysine and sorbose. The formation of CML also shows time-dependent differences between aldoses and ketoses. After heating up to 6–12 h, the reaction of lysine with ketoses leads to similar amounts of CML as the reaction with aldoses, whereas after longer heating significantly more CML was produced by the reaction with aldoses. The highest CML contents (2380 mg CML kg^?1 lysine) were measured in the galactose model system after heating for 24 h.     

Synthesis and 13C-NMR Spectroscopy of Methylated beta-Cyclodextrins

The methylated analogues of ß-cyclodextrin dissolve in cold water 10 – 20 times better than ß-cyclodextrin itself, however, quite unusually on heating they crystallize from the solution. The structure of heptakis-(2,6-di-O-methyl)- and heptakis-(2,3,6-tri-O-methyl)-ß-cyclodextrin was proved by gas-liquid chromatographic and ¹H-NMR and ¹³C-NMR spectroscopic investigations. The corresponding model compounds were synthetized and, according to ¹³C-NMR spectroscopic investigations, a part of the so far published NMR assignations have to be corrected.     

Loop-Mediated Isothermal Amplification (LAMP) for the Rapid and Sensitive Detection of Salmonella Typhimurium from Pork

ABSTRACT: Loop-mediated isothermal amplification (LAMP) is a novel molecular detection method that is more rapid and simpler than PCR. Products can be detected by turbidity using one temperature without the need for expensive PCR equipment. Our objective was to sensitively detect Salmonella Typhimurium from pork products within 1 d using the LAMP assay. Pork chop and pork sausage samples (25 g) were inoculated with high (10⁸ to 10⁶ CFU) and low (10⁵ to 10⁰ CFU) inocula of S. Typhimurium. Serial dilutions in phosphate buffered saline were plated on XLT4 agar either immediately or after selective preenrichment in tetrathionate broth (225 mL) for 10-h at 37 °C. Nucleic acid was extracted using the TRIzol^® method from 1-mL samples. The LAMP assay using 6 specific invA gene primers and Bst DNA polymerase reaction mix was carried out at 62 °C for 90 min in a waterbath. Turbid products were detected visually and by agarose gel electrophoresis. Improved Salmonella detection at 10² CFU/25 g for both pork chop and sausage was obtained after 10-h enrichment and 10⁶ CFU/25 g without enrichment for both products. This assay can detect Salmonella from pork within 1 d, significantly faster than traditional methods that take >5 d. This method shows tremendous potential for routine diagnostics and monitoring of Salmonella by the pork industry. Practical Application: The novel loop-mediated isothermal amplification (LAMP) assay is a rapid, specific, and sensitive method that has potential application for routine diagnostics of Salmonella from pork products. The isothermal method does not require expensive equipment such as a PCR thermocylcer but only a simple waterbath for amplification within 90 min. Detection is even simpler by visual eye or turbidimeters that are less expensive than fluorescent spectrophotometers or real-time PCR machines. All these advantages make it a practical approach for routine use by processing industries to rapidly detect Salmonella in their environment and to implement appropriate control strategies. To improve detection sensitivities, preenrichment followed by selective enrichment may be necessary. Even so, the entire assay can be completed at the most within two 8-h working shifts.     

Enhanced E/Z Isomerization of (All‐E)‐lycopene by Employing Iron(III) Chloride as a Catalyst

Catalytic isomerization of (all‐E)‐lycopene to Z‐isomers using iron(III) chloride was investigated and optimized under various conditions of solvents, concentrations of iron(III) chloride, and reaction temperatures. The total contents of Z‐isomers converted were higher in the order of CH₂Cl₂ (78.4%) > benzene (61.4%) > acetone (51.5%) > ethyl acetate (50.8%) at 20 °C for 3 h using 1.0 × 10^?3 mg/mL iron(III) chloride for 0.1 mg/mL (all‐E)‐lycopene. However, the decomposition of lycopene was markedly accelerated in CH₂Cl₂: the remaining lycopene after the reaction for 3 h and 12 h was only 79.4% and 47.5%, respectively. As the concentration of catalyst increased in acetone, the Z‐isomerization ratio of lycopene increased to more than 80%, followed by rapid degradation of lycopene to undetectable levels using >4.0 × 10^?3 mg/mL iron(III) chloride with the above concentration of (all‐E)‐lycopene. Finally, greater isomerization (79.9%) was attained at 60 °C in acetone for 3 h in the presence of 1.0 × 10^?3 mg/mL iron(III) chloride, largely without decomposition of lycopene (remaining ratio of total amount of lycopene isomers after the reaction, 96.5%). As iron(III) chloride has found general use as a food additive for iron fortification and acetone is also widely used in the food field, this method can be applied to the food and beverage processing industry.     

Theobromine Does Not Affect Fasting and Postprandial HDL Cholesterol Efflux Capacity,While It Decreases Fasting miR‐92a Levels in Humans

Scope

Chocolate consumption lowers cardiovascular disease risk, which might be attributed to the methylxanthine theobromine. These effects may be mediated through effects on HDL‐mediated cholesterol efflux, which may be affected by microRNA (miRNA) levels in the HDL particles. Therefore, the aim of this study is to investigate effects of theobromine consumption on fasting and postprandial cholesterol efflux and miRNAs levels.

Methods and results

Thirty overweight and 14 obese healthy men and women participated in this randomized, double‐blind crossover study. Participants consumed 500 mg d^?1 of theobromine or placebo for 4 weeks. ABCA1‐mediated cholesterol efflux was measured using J774 macrophages. MiRNAs levels (miR‐92a, miR‐223, miR‐135a*) were quantified in apolipoprotein B‐depleted serum. Theobromine consumption did not affect fasting and postprandial cholesterol efflux. Fasting miR‐223 and miR‐135a levels were unchanged, while miR‐92a levels were decreased (?0.21; p < 0.05). The high‐fat meal increased postprandial cholesterol efflux capacity (+4.3 percentage points; p ≤ 0.001), miR‐92a (+1.21; p < 0.001), and miR‐223 (+1.79; p < 0.001) levels, while a trend was found for miR‐135a (+1.08; p = 0.06).

Conclusion

Theobromine did not improve fasting and postprandial ABCA1‐mediated cholesterol efflux capacity, but decreased fasting miR‐92a levels. High‐fat meal intake increased postprandial cholesterol efflux and the three selected miRNAs levels.

     

Characteristics of Modified β‐Cyclodextrin Bound to Cellulose Powder

Monochlorotriazinyl‐β‐cyclodextrin (MCT‐β‐CD) was covalently bonded to cellulose powder. The amount of MCT‐β‐CD bonded to cellulose could be determined by infrared spectroscopy. The coupling reaction was characterized as a physical adsorption of the MCT‐β‐CD on the cellulose powder followed by an apparently zero order chemical reaction. The reaction rate constant was found to be k = 6.43 · 10^‐4 ± 0.11 · 10^‐4 g g^‐1 s^‐1. The immobilized cyclodextrin was able to include and release d‐limonene as a model flavor compound. The maximum molar inclusion ratio was 0.85, which is the same inclusion ratio as for d‐limonene in native β‐cyclodextrin. The release rates of dlimonene included in the fixed MCT‐β‐CD were monitored at various relative humidities and 50 °C. The release kinetics could be modeled using the Avrami equation. These results demonstrate that flavors as well as other hydrophobic compounds can be included and released from MCT‐β‐CD immobilized on cellulose.     

AN APPROACH TO THE IDENTIFICATION OF A ß-GLUCAN SOLUBILASE FROM BARLEY1

A ß-glucan solubilase activity was demonstrated in barley extract. This enzyme catalyzed the dissolution of barley ß-glucan by releasing a product having a narrow molecular weight distribution and a molecular weight of about 20,000. The enzyme was partially purified by ion exchange chromatography on DEAE-cellulose and gel permeation chromatography on Bio-Gel P-100. Although carboxypeptidase activity was present in the crude extract of barley flour the partially purified ß-glucan solubilase did not hydrolyse N-CBZ-Phe-ala. Examination of extracts from different barley tissues indicated that the ß-glucan solubilase activity was associated with the husks only; a large portion of the activity was extractable from whole barley kernels. About 85% of the enzyme activity in crude extracts from barley flour was retained after 40 min at 62°C. However, the enzyme was much more heat-labile in extracts of whole barley kernels. The pH of maximal activity was found to be about pH 5.7 and results from column chromatography suggested that the enzyme had a low pl value and a MW between 5 × 10⁴ and 6 × 10⁴.     

A novel global hydrodynamic analysis of the molecular flexibility of the dietary fibre polysaccharide konjac glucomannan

Konjac glucomannans have been widely considered in health food products although their hydrodynamic properties have been poorly understood. The weight-average molecular weight (M_w); sedimentation coefficient (s⁰_20,w) and intrinsic viscosities ([η]) have been estimated for five different preparations. The decrease in both intrinsic viscosity and sedimentation coefficient with molecular weight enables the estimation of molecular flexibility in terms of persistence length (L_p) using the traditional Bohdanecky–Bushin and Yamakawa–Fujii analyses for intrinsic viscosity and sedimentation data respectively. However, this requires an assumption of the mass per unit length M_L. Advantage can now be taken of a recent development in data interpretation which allows the estimation of L_p from combined intrinsic viscosity and sedimentation coefficient data and also an estimate for M_L. Using this “global” procedure an estimate of (13 ± 1) nm is found for L_p and a value of (330 ± 10) g mol⁻¹ nm⁻¹ for M_L.The value for L_p suggests a molecule of considerable flexibility, comparable to galactomannans (L_p  8–10 nm) but not as flexible as pullulan (L_p  1–2 nm).     

Sterols of seed oils of Vernonia galamensis,Amaranthus cruentus,Amaranthus caudatus,Amaranthus hybridus and Amaranthus hypochondriacus grown in the humid tropics

Analysis of sterols of seed oils from Vernonia galamensis, Amaranthus cruentus, A caudatus, A hybridus and A hypochondriacus, the last four being exotic breeds planted in the humid tropics of Africa, is presented in this report. Identifiable sterols in all the seed oil samples include campesterol, stigmasterol, ß-sitosterol, Δ⁵-avenasterol and Δ⁷-avenasterol except for Vernonia galamensis where cholesterol was detected (63.61 mg per 100 g oil).     

Chemotaxonomical analysis of the essential oil aroma compounds of four different<Emphasis Type="Italic"> Ocimum</Emphasis> species from southern India

The essential oil aroma compounds of four different Ocimum species ( O. americanum, O. basilicum, O. gratissimum and O. sanctum) from southern India were analysed by solid phase microextraction (SPME)/gas chromatography (GC)/flame ionization detection (FID), SPME/GC/mass spectrometry (MS) and olfactoric evaluations. The essential oil of the whole plant of O. americanum is rich in ( E)-methyl cinnamate (72.05%), ( Z)-methyl cinnamate (9.11%), camphor (5.95%) and ß-selinene (3.43%); the essential leaf oil of O. basilicum contains ( E)-methyl cinnamate (34.49%), linalool (28.44%), camphor (13.08%), ( Z)-methyl cinnamate (6.90%) and geraniol (3.84%), whereas the essential leaf oil of O. gratissimum comprises eugenol (63.36%), ( Z)-ß-ocimene (9.11%), germacrene D (8.84%) and ß-caryophyllene (3.89%). Finally, the essential leaf oil of O. sanctum shows methyl eugenol (56.18%), ß-caryophyllene (16.60%) and germacrene D (5.10%) as main constituents. Therefore, the following chemotypes can be attributed to the analysed Ocimum samples: O. americanum, methyl cinnamate-type; O. basilicum, methyl cinnamate/linalool-type; O. gratissimum, eugenol-type; and O. sanctum, methyl eugenol-type. The character impact compounds of the essential oils of the four investigated Ocimum samples, as well as a discussion of their possible use in food products, is also given.     

KINETICS OF THE INTERACTION OF PANCREATIC α-AMYLASE WITH A KIDNEY BEAN (PHASEOLUS VULGARIS) - AMYLASE INHIBITOR

An amylase inhibitor isolated from black beans (Phaseolus vulgaris) can completely inhibit porcine pancreatic α-amylase forming a 1:1 stoichiometric complex. The kinetic pattern of complex formation is pH dependent. At pH 5.5 it follows a first order reaction with rate constant of 0.029 min^?1 and 0.017 min^?1 at 37°C and equimolar inhibitor and enzyme concentration, respectively, of 10^?8 M and 10^?9 M. At pH 6.9 it is a second order reaction, with a rate constant of 0.25 × 10⁶ M^?1 min^?1 at 37°C, with 4 × 10^?8 M concentrations of enzyme and inhibitor. The dissociation constants of the enzymeinhibitor complex are 1.7 × 10^?10 M at pH 5.5 and 4.4 × 10^?9 M at pH 6.9, at 37°C. The kinetic data obtained at pH 5.5 suggested the formation of an initial reversible complex followed by a conformational change step. The complex can be dissociated either in acid pH (4.3) or at pH values higher than 6, 5 with partial recovery of the amylase activity.     

Effects of Osmotic Pressure on the Crosslinking Reaction of Tapioca Starch

Tapioca starch was crosslinked with 0.1 % sodium trimetaphosphate (STMP) in the presence of alkali and of osmotic pressure enhancing salts such as sodium sulfate and sodium chloride. The addition of various percentages of sodium sulfate to the crosslinking reaction mixture changed the pasting properties of the product starch as measured in the RVA (Rapid Visco Analyser). Peak viscosity (PV) and final viscosity (FV) are first increased with the increase in osmotic pressure followed by a decrease of the viscosities after further pressure increase. Breakdown (BD) is decreased in line with the increase of the osmotic pressure with very good correlation (R² = 0.96). These pasting characteristics are attributed to the inhibited swelling without disruption of the starch granules due to the crosslinking reaction. If sodium chloride is used as an osmotic pressure enhancer of the crosslinking reaction, both pasting properties (PV, FV) decrease linearly with the increase in osmotic pressure with very good correlation (R² = 0.98 and 0.99, respectively). The BD is dramatically decreased to zero (no breakdown) after applying the osmotic pressure and remains zero after further increase in osmotic pressure. These properties are also attributed to the pasting characteristics of the crosslinked starch. The increase in pasting temperature (PT) with increasing osmotic pressure for both sodium sulfate and sodium chloride demonstrates the increase of the gelatinization temperature of the starch granules. The enhancement of the osmotic pressure can promote the activity of the crosslinking agent.     

Production and Application of a Maltogenic Amylase by a Strain of Thermomonospora viridis TF-35

An extracellular and thermostable maltogenic amylase-producing moderate thermophile (Thermomonospora viridis TF-35), which grew well at 28–60°C, with optima at 45°C and pH 7, was isolated from soil. Maximal enzyme production was attained after aerobical cultivation for 32 h at 42°C with a medium (pH 7.3) composed of 2% (w/v) soluble starch, 2% gelatin hydrolyzate, 0.1% K₂HPO₄ and 0.02% MgSO₄ · 7H₂O. The partially purified enzyme, which was most active at 60°C and pH 6.0 and stabilized with Ca²⁺, converted about 65, 80, 75, 75, 65 and 60% of maltotriose, maltotetraose, maltopentaose, amylose, amylopectin and glycogen into maltose as a major product under the conditions used, respectively. Glucose and small amounts of maltooligosaccharides were also formed concomitantly as by-products. The molar ratio of maltose to glucose from maltotriose were larger than 1 during all stages of the hydrolysis. About 70 and 76% of 25% (w/v) potato starch liquefites having a 3.5 DE value were converted into maltose by the enzyme in the absence and presence of pullulanase during the saccharification, respectively. About 90 and 94% of the starch liquefites were also converted into maltose with relatively low contents of maltooligosaccharides by the cooperative 2 step reaction with the enzyme after obtaining starch hydrolyzates containing about 85 and 90% maltose by the simultaneous actions of soybean ß-amylase and debranching enzymes.     

Rapid and Sensitive Detection of Staphylococcus aureus in Food Using Selective Enrichment and Real-Time PCR Targeting a New Gene Marker

Staphylococcus aureus is a bacterial pathogen considered a principal etiological agent of food poisoning. The aim of this study was to develop and evaluate a rapid and sensitive method for the detection of S. aureus in food by using selective enrichment and a new species-specific real-time polymerase chain reaction (PCR). Specific primers and a TaqMan probe targeted to specific S. aureus gene encoding for acriflavine resistance protein were designed. The real-time PCR was highly specific for S. aureus with 100% inclusivity and 100% exclusivity determined using 83 S. aureus strains and 64 non-S.-aureus strains. PCR detection limit of 6.8 × 10¹ and 3.4 × 10¹ CFU ml⁻¹ were obtained with 100% and 70% detection probability, respectively. The single selective enrichment based on the study of different enrichment conditions was selected and a lysis by boiling was used to obtain bacterial DNA. Out of 112 food samples analyzed, 61 were positive by the PCR-based method and 53 by the standard method. Out of ten food matrices artificially contaminated at a level of 10° CFU g⁻¹, ten and six were positive by the respective methods. Moreover, 10° CFU 10 g⁻¹ was detected in all ten artificially contaminated samples after a large-scale enrichment using PCR-based detection, in contrast to seven false negative by standard detection. The developed method facilitated the detection of S. aureus on the next day after the sample reception. This method can be used for S. aureus detection as a faster, highly specific, and more sensitive alternative to microbiological method with the potential for providing of improved food-processing hygiene control.     

MALDI-based identification of stable hazelnut protein derived tryptic marker peptides

Food allergy is an important health problem especially in industrialised countries. Tree nuts, among which are hazelnuts (Corylus avellana), are typically causing serious and life-threatening symptoms in sensitive subjects. Hazelnut is used as a food ingredient in pastry, confectionary products, ice cream and meat products, therefore undeclared hazelnut can be often present as a cross-contaminant representing a threat for allergic consumers. Mass spectrometric techniques are used for the detection of food allergens in processed foods, but limited information regarding stable tryptic peptide markers for hazelnut is available. The aim of this study was to detect stable peptide markers from modified hazelnut protein through the Maillard reaction and oxidation in a buffered solution. Peptides ³⁹⁵Gly-Arg⁴⁰³ from Cor a 11 and ²⁰⁹Gln-Arg²¹⁷, ³⁵¹Ile-Arg³⁶³, ⁴⁶⁴Ala-Arg⁴⁷⁸ and ⁴⁰¹Val-Arg⁴¹⁷ from Cor a 9 hazelnut allergens proved to be the most stable and could be detected and confirmed with high scores in most of the modified samples. The identified peptides can be further used as analytical targets for the development of more robust quantitative methods for hazelnut detection in processed foods.     

Modelling the effect of superatmospheric oxygen concentrations on in vitro mushroom PPO activity

The kinetics of polyphenol oxidase (PPO, EC 1.14.18.1) with respect to oxygen concentrations from 5 to 100% using chlorogenic acid (CGA) as substrate was examined. In vitro mushroom PPO activity was determined by measuring the consumption of oxygen during the oxidation reaction. A differential Michaelis–Menten model was fitted to the obtained total depletion curves. The product concentration as well as the concentration of oxygen had a clear inhibitory effect on the reaction rate. However, the inhibitory effect of oxygen was more evident at low product concentration. A linear mixed inhibition model that considered both the product (oxidised CGA) and oxygen as inhibitors was developed. A model with the product as a competitive inhibitor and oxygen as an uncompetitive inhibitor was the most appropriate to explain the reaction kinetics. The values of the inhibition constants calculated from the model were 0.0032 mmol L⁻¹ for K_m (Michaelis–Menten constant related to oxygen), 0.023 mmol L⁻¹ for K_mc (constant for competitive inhibition due to the product), 1.630 mmol L⁻¹ for K_mu (constant for uncompetitive inhibition due to oxygen) and 1.77 × 10⁻⁴ mmol L⁻¹ s⁻¹ for V_max (maximum reaction rate). The results indicate that superatmospheric oxygen concentrations could be effective in preventing enzymatic browning by PPO. Copyright © 2006 Society of Chemical Industry