Feeding strategy for improving tenderness has opposite effects in two different muscles

Compensatory growth has been shown to affect rate of muscle protein turnover and may potentially improve tenderness of beef. Thus, a study of tenderness in relation to feeding regime and slaughtering at a time with maximal muscle protein degradation was performed. Friesian bull calves (5-month-old) were fed either ad libitum (n = 6) (AA) or restrictively for 3 months followed by re-alimentation for 6 weeks (n = 6) (RA) before slaughter at 10 months. At slaughter the fractional breakdown rate of muscle protein was 2.4% in RA compared with 1.6% in AA (P < 0.06). Sensory profiling revealed superior texture of M. semimembranosus from RA compared with AA, whereas M. longissimus was superior in texture from AA compared with RA, with no difference in proteolysis and shear force. In conclusion it was clear that different muscles in terms of tenderness responded very differently to the nutritional manipulation.     

Moisture diffusivity and shrinkage of broad beans during bulk drying in an inert medium fluidized bed dryer assisted by dielectric heating

Drying behavior of broad beans (Vicia faba) was studied in a pilot scaled fluidized bed dryer with inert particles assisted by dielectric heating. The effective diffusion coefficient of moisture transfer was determined by Fickian method at four different air drying temperatures of 35, 45, 55 and 65 °C. Correlations for moisture diffusivity as a function of moisture content and temperature of the drying medium were developed. The values of moisture diffusivity were obtained within the range of 1.27 × 10^?9–6.48 × 10^?9 m²/s and the activation energies for FBD and FBD + DE were found to be 27.71 and 17.10 kJ/mol, respectively. The shrinkage behavior of the broad beans was also investigated by considering the volume ratio of (V/V_O) to be function of moisture content alone and fitting a polynomial of the third order. The dielectric heating power was also found to be effective on the rate of drying.     

Curcuminoid content and antioxidant activity in spray dried microparticles containing turmeric extract

Curcuma longa L., also known as turmeric, is widely used as a food colorant and has been reported to have antioxidant, anti-inflammatory, anti-mutagenic and anti-cancer properties. The aim of this study was to evaluate the effects of the spray drying on curcuminoid and curcumin contents, antioxidant activity, process yield, the morphology and solubility of the microparticulated solid dispersion containing curcuma extract using a Box Behnken design. The microparticles were spherical in shape, and an increase in outlet temperature from 40 to 80 °C resulted in a significant increase in the yield of microparticles from 16 to 53%. The total curcuminoid content (17.15 to 19.57 mg/g), curcumin content (3.24 to 4.25 mg/g) and antioxidant activity (530.1 to 860.3 μg/mL) were also affected by the spray drying process. The solubility of curcuminoid from C. longa remarkably improved 100-fold in the microparticles, confirming the potential of the ternary solid dispersion technique to improve the dyeing and nutraceutical properties of these compounds. Furthermore, the microparticles were obtained using the spray drying process, can be easily scaled up.     

Retention of Physicochemical and Antioxidant Properties of Dehydrated Bael (Aegle Marmelos) and Palmyra (Borassus Flabellifer) Fruit Powders

Present study was carried out to evaluate the effect of various dehydration techniques such as sun drying, solar drying, drying after freezing (Freeze for one hour followed by mechanical drying at 55 °C), vacuum drying and drying using lab scale air oven on proximate composition and retention of antioxidants in different fruit powder prepared from Bael (Aegle marmelos) and Palmyra (Borassus flabellifer). Moisture content, Total Ash, Crude fiber %, Fat %, Crude protein %, total phenolic content,β –Carotene and antioxidant activity were tested. The antioxidant activity was measured based on the ability of fruit extract to scavenge 1, 1- diphenyl-2-picrylhydrazyl (DPPH). Among different drying treatments the highest fat percentage recorded by the solar dried palmyra fruit powder and there is no significant difference (α= 0.05) between sun drying and vacuumed drying. Higher concentration of β -Carotene and total phenolic content were recorded in vacuum dried samples both in bael and Palmyra fruit powders and it significantly different (α= 0.05) from other treatments. The scavenging activity of bael fruit powder in vacuum drying was ranged from 65.36% to 81.33% of the concentration 200 μg/ml to1000 μg/ml and the palmyra fruit powder was recorded 57.32% to 83.25% of the concentration 200 μg/ml to1000 μg/ml. Vacuum dried fruit powders of palmyra and bael were given highest radical scavenging activity and the scavenging activity of palmyra fruit powder is higher than the bael. Therefore vacuum drying can be recommended as the most effective drying method to protect chemical characteristics and retention of antioxidant properties of fruit powders.     

Effect of apparent density of sliced food particles on the efficiency of pulsed electric field treatment

This work discusses the effects of pulsed electric field (PEF) (electric field strength, E, 100–1000 V; pulse duration, t_p, 100 μs) on disintegration of potato slices treated between parallel plate electrodes by using a laboratory compression chamber equipped with a PEF-treatment system. The apparent density of slices (bed of particles), ρ, was varied within 0.313 g/cm³ and 1 g/cm³. The electrical conductivity σ(ρ) of the packing of slices versus volume fraction of particles ϕ was approximated by the percolation law σ ∝ (φ − φ_c)^t, where ϕ_c ≈ 0.290, t = t_i ≈ 0.46 and t = t_d ≈ 1.39 for the intact and completely damaged tissues, respectively. The impact of electric field strength and apparent density of slices on PEF-induced damage kinetics was studied. The more accelerated kinetics of damage was observed for more dense packing of slices. The approximated relation between the applied, E, and effective, E_e, electric field strengths accounting for the σ(ρ) dependence was derived.Industrial relevanceThe practical applications of PEF treatment (e.g., pressing, drying, extraction, etc.) demand operations with slices of food particles. In this study, research towards the electroporation efficiency of PEF applied to the porous packing of sliced food particles is provided.     

Emulsifying characteristics of commercial canola protein–hydrocolloid systems

Emulsifying properties of commercial canola protein isolate (CPI)–hydrocolloid-stabilized emulsions were evaluated under varied conditions (CPI, salt and hydrocolloid concentrations; pH, denaturants). Emulsifying activity index (EAI) and emulsion stability (ES) were determined by turbidimetric testing. The results showed that under complexing conditions (at pH 6), the addition of 1% (w/v) κ-carrageenan (κ-CAR) increased the EAI of CPI-stabilized emulsions from 162 to 201 m²/g and ES from 68% to 95%. Under conditions promoting incompatibility (at pH 10), the use of 1% (w/v) guar gum increased the EAI of CPI-stabilized emulsions from 68 to 177 m²/g and ES from 66% to 100%. The lower EAI and ES values observed in CPI–hydrocolloid-stabilized emulsions treated with sodium salts and denaturants support the involvement of hydrophobic interactions, hydrogen bonds and disulfide linkages in the emulsification of these systems. Interfacial properties of CPI–hydrocolloid mixtures were improved by electrostatic complexing and incompatibility, making these systems suitable for stabilizing food emulsions.     

Physical alterations of soybean during accelerated and natural aging

The aim of the present study was to investigate the effect of accelerated aging (AA) and natural aging (NA) on the physical characteristics of soybeans (Glycine max). Soybeans from two cultivars (Coodetec 214 and BRS 267) were stored under AA (30 °C and 84% RH up to nine months), NA (ambient temperature and RH, fluctuation in the period = 17.3 at 24.5 °C and 59 at 93% RH, up to 18 months), and control conditions (− 20 °C and 47% RH). Scanning electron micrographs (SEM) of the hull and cotyledons, the water sorption rate (S) during hydration and equilibrium moisture content (X_eq), the color of the grains and ground soybeans, and the hardness of cooked soybeans were analyzed. After storage of AA and NA, the surface of the palisade cells of the cotyledons became wrinkled and wilted; the browning of the hull, the ground soybeans, and the hardness of the cooked soybeans increased for both cultivars. It was observed that the increase of S and decrease of X_eq were more pronounced in Coodetec 214 than BRS 267.     

Modeling the effect of natamycin,pine-resin and environmental factors on the growth and OTA production by Aspergillus carbonarius using response surface methodology

The effect of two antifungal compounds (natamycin, pine-resin), temperature and water activity, on the growth rate, lag phase duration and Ochratoxin A (OTA) production by three Aspergillus carbonarius isolates (Ac-28, Ac-29, and Ac-33), was studied by means of Response Surface Methodology (RSM) based on a Central Composite Design (CCD). Two different experimental designs were performed as a function of temperature (16.6–33.4 °C), water activity (0.90–0.97 a_w), natamycin (0–1000 ng ml^− 1) or pine-resin (0–2.61%, w/v) on a Synthetic Grape-juice Medium (SGM). OTA production was analyzed after 5, 10 and 15 days of incubation. A second-order polynomial model was fitted to each response parameter to assess the growth and OTA potential of all fungal isolates. Results showed that natamycin, a_w and temperature had significant effects on the lag phase duration of all isolates, as well as on OTA accumulation after 10 days of incubation for Ac-29 and 15 days for Ac-28 and Ac-33 isolates. The same results were obtained for OTA production after treatment with pine-resin. However, fungal growth rates were not statistically significant in both experiments, with the exception of Ac-29 and Ac-33 after treatment with pine-resin. Overall, high natamycin concentrations (800 and 1000 ng ml^− 1) delayed fungal growth depending on the environmental factors assayed. Moreover, treatment with pine-resin at 16.6 °C/0.94 a_w/1.1% w/v, as well as at 25 °C/0.90 a_w/1.1% w/v, completely inhibited fungal growth up to 15 days of incubation.     

Enzymatic catalysis in a whey protein matrix at temperatures in the vicinity of the glass transition

The current study evaluates the effect of temperature on α-glucosidase activity, following incorporation of the enzyme into a whey protein matrix through spray drying. Thermomechanical characterization of the matrix was achieved using the techniques of modulated temperature differential scanning calorimetry and small-deformation dynamic mechanical analysis. As the concentration was raised from 75 to 94% (w/w), denaturation of the protein occurred at increasing temperatures. In contrast, denaturation was not observed in calorimetric scans after spray drying. The glass transition temperature (T_g) measured in the dried particles using dynamic mechanical analysis was approximately 40 °C. An optimized procedure was developed whereby α-glucosidase and its substrate p-nitrophenyl α-d-glucopyranoside were incorporated into the whey matrix. The effect of temperature on enzymatic catalysis was investigated and, below 40 °C, activity was low and relatively independent of temperature. However, the rates of product formation markedly accelerated as temperatures were increased beyond T_g. These novel observations strongly emphasize the pronounced effect of mechanical T_g of the protein matrix on enzymatic activity.     

An investigation into lactose crystallization under high temperature conditions during spray drying

Lactose crystallization was studied at high temperature conditions in a Buchi B-290 mini spray dryer. The inlet gas temperature was 200 °C, and an insulating material was used to reduce the heat loss from the drying chamber (outlet temperature 157 °C), thus increasing the gas and particle temperatures. At these conditions, lactose crystallinity was found to increase significantly compared with a case where it was spray dried at 170 °C in a non-insulated drying chamber (outlet temperature 90 °C), but the process yield was lower for the former case (0.16% yield) than for the low temperature conditions (47% yield). There is some evidence that high-temperature spray drying of lactose is more likely to give more β-lactose anomer. Different analytical techniques (Fourier Transform Infrared Spectroscopy, modulated differential scanning calorimetry, moisture sorption test, Raman spectroscopy) were used to investigate the degree of crystallization and possible lactose anomer formation during this spray drying at high inlet gas temperatures.     

Oil composition,mineral nutrient and fatty acid distribution in the lipid classes of underutilized oils of Trilepisium madagascariense and Antiaris africana from Nigeria

Trilepisium madagascariense (TM) and Antiaris africana (AA) are two underutilized plants from Nigeria. They have been subjected to standard analytical techniques in order to evaluate the proximate composition, physico-chemical properties, mineral nutrient, fatty acid composition and distribution in the lipid classes of the seeds and seed oils. The carbohydrate composition of these seeds are high; TM is 62.73 ± 0.30% and AA is 53.97 ± 0.50%. Iodine value of TM was found to be 46.10 ± 0.70 mg iodine/g while that of AA was 88.24 ± 0.50 mg iodine/g. The mineral composition of the seeds and the oils varied with K having the highest concentration in the seed and Na the highest concentration in the oils. Linoleic acid is the dominant fatty acid in the oil of AA with the highest composition in the neutral lipids while palmitic acid is the dominant fatty acid in oil of TM. Vitamin E, Gamma-Sitosterol, α and β-Amyrin, Lupeol, Stigmast-4-en-3-one, and hydrocarbons were isolated from these oils. The results of the proximate, mineral nutrient compositions, chemical characterization and fatty acid distribution of these seeds and seed oils shows their possibility as potential resources.     

Formulation with ascorbic acid and sucrose modulates catechin bioavailability from green tea

In order to investigate the impact of common food ingredients on catechin absorption, green tea (GT) extract (50 mg) was formulated plain, with sucrose (GT + S), with ascorbic acid (GT + AA) and with sucrose and ascorbic acid (GT + S + AA). Bioavailability and bioaccessibility were assessed in Sprague Dawley rats and an in vitro digestion/Caco-2 cell model respectively. Absorption of epigallocatechin (EGC) and epigallocatechin gallate (EGCG) was significantly (P < 0.05) enhanced in GT + S + AA formulations (AUC_0–6 h = 3237.0 and 181.8 pmol h/L plasma respectively) relative to GT control (AUC_0–6 h = 1304.1 and 61.0 pmol h/L plasma respectively). In vitro digestive recovery was higher for EGC and epicatechin (EC) (～51–53%) relative to EGCG and epicatechin gallate (ECG) (<20%) and was modestly enhanced in GT + S and GT + S + AA formulations. Accumulation of EGC, EGCG and ECG by Caco-2 cells was significantly (P < 0.05) higher from GT + S + AA compared to other formulations while retention of catechins was enhanced in presence of ascorbic acid. These data suggest that formulation with sucrose and ascorbic acid may improve catechin bioavailability by enhancing bioaccessibility and intestinal uptake from tea.     

The effect of pH on the gelling behaviour of canola and soy protein isolates

The present study investigates the gelation mechanisms of a canola protein isolate (CPI) as a function of a pH (3.0–9.0), and compares it to that of a commercial soy protein isolate (SPI). A rheological investigation found that CPI was non-gelling at pH 3.0, and then formed a gel with increasing strength as pH was raised from pH 5.0 to 9.0. In contrast, the commercial SPI ingredient was found to be non-gelling at pH 9.0, but formed the strongest networks at pH 5.0 near its isoelectric point (pI = 4.6). Denaturation temperature as determined by differential scanning calorimetry were found to occur at ~ 78 °C for CPI at pH 5.0, then shifted to higher temperatures (~ 87 °C) at pH 7.0/9.0, whereas detection of SPI denaturation could not be obtained due to instrument sensitivity. Gelling temperatures were similar for both CPI and SPI (~ 82–86 °C) at all pHs, with the exception of SPI at pH 5.0 (~ 46 °C). Overall CPI networks were stronger than SPI, since the latter had weaker inter- and intramolecular junction zones. Confocal laser scanning microscopy images indicated that CPI gels became denser with lower lacunarity values as pH increased from 3.0 to 9.0. Moreover, the fractal dimension of CPI gels was found to increase from ~ 1.5-1.6 to ~ 1.8 as pH increased from 5.0/7.0 to 9.0, respectively suggesting diffusion-limited cluster-cluster aggregation. Images of SPI networks were not concurrent with fractal analysis under the conditions examined. Despite CPI having excellent gelling properties that are comparable to SPI, its need for alkaline pH conditions will limit its applicability in foods.     

Comparison of antimicrobial resistance patterns and phage types of Salmonella Typhimurium isolated from pigs,pork and humans in Belgium between 2001 and 2006

Infections with non-typhoid Salmonella represent a major problem in industrialized countries.The emergence and spread of antimicrobial-resistant pathogens, among them Salmonella, has become a serious health hazard worldwide. One of the most commonly isolated non-typhoid Salmonella serovars in pigs, pork and humans is Salmonella Typhimurium. In this study the comparison of the incidences of resistance to nine antimicrobials, resistance patterns and phage types between S. Typhimurium isolated from pigs (n = 581), pork (n = 255) and humans (n = 1870) in Belgium in the period 2001 to 2006 was performed.Resistance to the antimicrobials ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline was frequently observed and varied between 23.5% and 83.1%. Resistance ranged from 15.6% to 20.7% for the combination trimethoprim–sulfonamides and from 3.4% to 5.8% for nalidixic acid. Resistance to the critical important antimicrobials cephalosporins and fluoroquinolones was found sporadically (≤ 1.2%). Resistance to the different antimicrobials was observed to be similar in S. Typhimurium isolates from the various origins. Twenty-seven antimicrobial resistance patterns representing in total 75.2%, 89.0% and 89.6% of the isolates from pigs, pork and humans respectively were found to be common among the three groups and 73 combinations antimicrobial resistance pattern/phage type were found to be common among pork and human isolates, representing 70.1% of the pork isolates and 51.0% of the human isolates. The high percentage of isolates that have a common resistance pattern, and in a less pronounced way a common combination phage type/resistance pattern, are in agreement with the hypothesis of transfer of antimicrobial resistant Salmonella from pigs via the consumption of pork to humans as one of the possible pathways. The most prevalent combination in Belgium within both the pork isolates (7.4%) and the human isolates (13.2%) was S. Typhimurium DT104 resistant to ampicillin, chloramphenicol, streptomycine, sulfonamides and tetracycline.     

Effects of combined high-pressure homogenization and enzymatic treatment on extraction yield,hydrolysis and function properties of peanut proteins

Peanut protein isolate (PPI) was extracted by high-pressure homogenization (HPH) under 0.1 MPa (atmospheric pressure) and 40 or 80 MPa (high pressure). Effects of Alcalase (a proteolytic enzyme) on the enzymatic hydrolysis of PPI and the antioxidant activity of the PPI hydrolysates were investigated. The molecular weight distributions of the PPI hydrolysates were analyzed using Sephadex G-25 gel filtration chromatography while the antioxidant activities, including reducing power, 1,1-dipheny-2-picrylhydrazyl (DPPH) radical-scavenging activity and hydroxyl free radical-scavenging activity of the PPI hydrolysates were evaluated. The extraction yields of PPI by HPH under 0.1, 40 and 80 MPa were 16.84, 30.65 and 39.86%, respectively, which showed that HPH treatment improved the PPI extraction. The HPH treatment increased the degree of hydrolysis of PPI and significantly increased the reducing power and hydroxyl radical­scavenging activity. Furthermore, the molecular weight distributions of the PPI hydrolysates appeared principally over the range of 1000–5000 Da, while the HPH treatment enhanced the production of small peptides, which was in agreement with the high PPI hydrolysis degree. These results suggest that HPH treatment in combination with enzymatic hydrolysis could modify PPI properties and increase the antioxidant activities of the PPI hydrolysates.Industrial relevanceThis study was focused to evaluate the effects of high-pressure homogenization (HPH) in combination with enzymatic hydrolysis on extraction yield and enzymatic hydrolysis of PPI and antioxidant activity of the PPI hydrolysates. This study indicated the possibility of improving the availability of PPI by HPH treatment via increasing extraction yield and enzymatic hydrolysis of the PPI, which can provide a better utilization of the peanut by-product.     

Modelling of red abalone (Haliotis rufescens) slices drying process: Effect of osmotic dehydration under high pressure as a pretreatment

Simultaneous application of osmotic dehydration and high pressure as a pretreatment to drying process on red abalone (Haliotis rufescens) slices was studied. During drying process the process time was reduced by increasing temperature from 40 to 60 °C along with the application of different pretreatments: high pressure (350 and 550 MPa), pressure time (5 and 10 min), and osmotic solution (10 and 15% NaCl). Effective moisture diffusivity was determined and varied from 4.35 to 9.95 × 10^− 9 m²/s, for both control and pretreated samples (R² ≥ 0.97). The Weibull, Logarithmic and Midilli–Kucuk models were applied to drying experimental data, where Midilli–Kucuk model was found to be the best fitting model. Furthermore, all drying curves were normalized and then modelled by the same three above models showing a R² ≥ 0.96. As to energy consumption and efficiency values for drying processes were found to be in the range of 777–1815 kJ/kg and 8.22–19.20%, respectively. Thus, knowledge on moisture transfer kinetics, energy consumption and data normalization, is needed to manage and control efficiently drying process under different pretreatment conditions.Industrial relevanceThis article deals with the mass transfer modelling and energy consumption during simultaneous high hydrostatic pressure treatment and osmotic dehydration as a pretreatment to drying process of abalone slices. Water and salt transfer during this combined process was satisfactorily simulated with the Midilli–Kucuk model. Results indicated that application of this combined innovative technology improved abalone slices dehydration rates compared to atmospheric pressure operation resulting in a dried abalone with intermediate moisture content ready to be used as input material of further processes. Furthermore, the different energetic features were determined in order to realize the importance of the changes that can influence to alter process time.     

Response surfaces of apricot kernel oil yield in supercritical carbon dioxide

Response surface methodology was used to determine the effects of solvent flow rate (2, 3 and 4 g/min), pressure (30, 37.5 and 45 MPa), temperature (40, 50 and 60 °C), and co-solvent concentration (0, 1.5 and 3 wt% ethanol) on oil yield of apricot (Prunus armeniaca L.) kernel oil in supercritical carbon dioxide (SC-CO₂). All the parameters had significant effects on oil yield as well as the interactions between solvent flow rate and pressure, and between pressure and temperature. Oil yield increased with increased parameters. The oil yield was represented by a second-degree polynomial equation. The maximum oil yield from the response surface equation was obtained as 0.26 g/g kernel for 15 min extraction of 5 g apricot kernel particles (particle diameter<0.850 mm) with 4 g/min solvent flow rate containing 3 wt% ethanol at 45 MPa and 60^oC. The response surface equation predicted the experimental oil yield with a 10% error. The fatty acid compositions of apricot kernel oils extracted with SC-CO₂ and hexane were similar.     

PFGE characterisation and adhesion ability of Listeria monocytogenes isolates obtained from bovine carcasses and beef processing facilities

Listeria monocytogenes is a pathogen capable of adhering to many surfaces and forming biofilms, which may explain its persistence in food processing environments. This study aimed to genetically characterise L. monocytogenes isolates obtained from bovine carcasses and beef processing facilities and to evaluate their adhesion abilities. DNA from 29 L. monocytogenes isolates was subjected to enzymatic restriction digestion (AscI and ApaI), and two clusters were identified for serotypes 4b and 1/2a, with similarities of 48% and 68%, respectively. The adhesion ability of the isolates was tested considering: inoculum concentration, culture media, carbohydrate source, NaCl concentration, incubation temperature, and pH. Each isolate was tested at 10⁸ CFU mL^− 1 and classified according to its adhesion ability as weak (8 isolates), moderate (17) or strong (4). The isolates showed higher adhesion capability in non-diluted culture media, media at pH 7.0, incubation at 25 °C and 37 °C, and media with NaCl at 5% and 7%. No relevant differences were observed for adhesion ability with respect to the carbohydrate source. The results indicated a wide diversity of PFGE profiles of persistent L. monocytogenes isolates, without relation to their adhesion characteristics. Also, it was observed that stressing conditions did not enhance the adhesion profile of the isolates.     

Subunit,amino acid composition and in vitro digestibility of protein isolates from Chinese kabuli and desi chickpea (Cicer arietinum L.) cultivars

The subunit, amino acid composition and in vitro digestibility of the two protein isolates (GCPI and ZCPI) from one kabuli and one desi chickpea cultivars, grown extensively in Xinjiang Autonomous Region of China, were investigated and compared with those of soy protein isolate (SPI). SDS–PAGE showed that GCPI and ZCPI had almost the same band components under the reduced and unreduced conditions, with only minor difference in relative quantity for some bands, but different from that of SPI. The sulphur-containing amino acids were the first limiting amino acids for all three protein isolates of GCPI (2.11 g/100 g), ZCPI (2.20 g/100 g) and SPI (1.99 g/100 g). Amino acid score of the three protein isolates could reach the FAO/WHO requirement (1990) for the essential amino acids for preschool children. The order of in vitro digestibility was GCPI (87.47%) > ZCPI (80.82%) > SPI (71.04%). Our results indicated that, compared with soybean protein isolate, Chinese kabuli and desi chickpea protein isolates had higher digestibility value, and chickpea protein, especially for kabuli protein, could be utilized as a good source of protein for human nutrition.