Crystallisation kinetics of palm stearin,palm kernel olein and their blends

The kinetics of isothermal crystallisation of palm stearin, palm kernel olein and their blends (20–80 g/100 g palm stearin with 20 g/100 g increment) were determined using differential scanning calorimetry (DSC). The mechanism of crystallisation (n) was calculated by applying the Avrami equation using the crystallisation curves obtained at 10, 15 and 20 °C. The DSC isothermal crystallisation data at 10, 15 and 20 °C fitted well into the Avrami equation over the entire fractional crystallisation with correlation coefficient always greater than 0.98. Based on the Avrami exponent obtained, the palm stearin and palm kernel olein have different nucleation and growth mechanisms. The suggested mechanism for palm kernel olein was high nucleation rate at the beginning of crystallisation, which decreased with time, and plate-like growth (n = 2). On the other hand, the mechanism for palm stearin was instantaneous heterogeneous nucleation followed by spherulitic growth (n = 3). For blends of palm stearin and palm kernel olein, the mechanisms of crystallisation were 2 and 3 depending on the composition of the blends and crystallisation temperatures.     

Thermal behavior of concentrated oil-in-water emulsions based on soybean oil and palm kernel olein blends

Droplet size distribution and thermal behavior of concentrated oil-in-water emulsions based on soybean oil (SBO)/palm kernel olein (PKO) blends were investigated. The emulsions were prepared using 70% (wt./wt.) oil blends of SBO/PKO as dispersed phases and stabilized by egg yolk. An increase in PKO level (0–40% wt./wt.) in the oil dispersed phase volume fraction caused significant increases (p < 0.05) in volume-weighted mean diameter (d_4,3). The DSC data suggested that crystallization of the emulsions was induced by a ‘template effect’ of yolk constituents via a surface heterogeneous nucleation. Emulsions with 0–20% (wt./wt.) PKO levels in the dispersed phase demonstrated a good cool–heat stability even after three successive thermal cycles (from 50 °C to ?70 °C at 10 min/°C). After the first thermal cycle, emulsions with 30% and 40% PKO levels in the oil dispersed phase were destabilized due to strong coalescence and crystallized via volume-surface heterogeneous nucleation. The unstable emulsions were attributable to high level of saturated triacylglycerols from PKO, with high droplet size characteristic, causing them to be more prone to partial coalescence.     

Mercury speciation in the muscle of two commercially important fish,hake (Merluccius merluccius) and striped mullet (Mullus barbatus) from the Mediterranean sea: estimated weekly intake

Total mercury and methylmercury concentrations were measured in the muscle tissue of two fish species from the Ionian and Adriatic seas. Higher total mercury and methylmercury concentrations were detected in striped mullet (Mullus barbatus), a benthic species (Ionian sea: Hg=0.40 μg g⁻¹ wet wt, MeHg=0.40 μg g⁻¹ wet wt; Adriatic sea: Hg=0.49 μg g⁻¹ wet wt, MeHg=0.44 μg g⁻¹ wet wt), than in hake (Merluccius merluccius), a pelagic species (Ionian sea: Hg=0.09 μg g⁻¹ wet wt, MeHg=0.09 μg g⁻¹ wet wt; Adriatic sea: Hg=0.18 μg g⁻¹ wet wt; MeHg=0.16 μg g⁻¹ wet wt). Total mercury residues were determined in all samples of both species from the Adriatic sea, while levels below the limit of detection were registered in 25% and 11%, respectively, of striped mullet and hake samples from the Ionian sea. In 18.8% and 22.2% of striped mullet samples from the Ionian and Adriatic seas, respectively, total mercury concentrations exceeded the maximum level fixed by the European Commission Decision (Hg=0.5 μg g⁻¹ wet wt). In the two different species, mercury was present almost completely in the methylated form with mean percentages between 60% and 100%. The estimated weekly intake for total mercury was below the established the provisional tolerable weekly intake (PTWI) for both species, though their consumption provides a methylmercury intake above the WHO safety limit.     

Effects of high intensity ultrasound and emulsifiers on crystallization behavior of coconut oil and palm olein

The objective of this research is to evaluate the crystallization behavior of coconut oil (CO) and palm olein (PO) as affected by the addition of two monoacylglycerols (MAG) emulsifiers and by the use of high intensity ultrasound (HIU). MAG with high content of palmitic, oleic, and linoleic acid (EM1) and MAG with high content of stearic acid and no unsaturated fatty acids (EM2) were used. Results show that the addition of emulsifiers did not affect crystallization kinetics of CO and similar solid fat contents (1.32 ± 0.94) (SFC) and melting enthalpies (5.90 ± 4.56) were obtained. The addition of EM1, however, significantly delayed the crystallization of PO as evidenced by a significantly lower SFC and melting enthalpy. SFC for PO was 8.56 ± 0.913 while SFC for PO + EM1 was 3.63 ± 1.38. Sonication induced the crystallization of CO samples crystallized with and without EM1 and EM2 while only induced the crystallization of PO + EM1 as measured with SFC. The induction in crystallization by HIU was also evidenced by higher enthalpy with values up to a range of 8 J/g to 11 J/g. A decrease in elasticity from 3.17 × 10⁶ to 2.52 × 10⁵ was observed in CO crystallized with emulsifiers which could be reverted by the application of HIU. Contrarily, the addition of emulsifiers increased elasticity of PO from 3.35 × 10² to 4.83 × 10⁴ and sonication did not affect these values significantly. Differences observed in elasticity values are attributed not only to the amount of solid material obtained but also to the type of microstructure of the crystalline network formed during crystallization.     

Antioxidant activity of palm oil carotenes in organic solution: effects of structure and chemical reactivity

The antioxidant effectiveness of palm oil α-carotene and comparison with β-carotene in organic solution containing egg-yolk phosphatidycholine (EYPC) in the presence of lipid soluble 2,2¹-azobis (2,4-dimethyl valeronitrile) (AMVN)-generated peroxyl radicals was investigated by measuring the formation of phosphatidyl choline hydroperoxide (PCOOH) and thiobarbituricacid reacting substances (TBARS). Lutein and zeaxanthin (xanthophylls), similar to α and β carotenes, respectively, but differing in containing hydroxyl groups on the two rings (3,3¹-diol), were also included in the investigation. The carotenes were more rapidly oxidised than the xanthophylls in the solution. The initial rates of oxidation of the carotenoid tested were 0.39 μM min⁻¹ (α-carotene), 0.44 μM min⁻¹ (β-carotene), 0.30 μM min⁻¹ (lutein) and 0.33 μM min⁻¹ (zeaxanthin). Incubation of EYPC with AMVN at 37°C induced the accumulation of PCOOH at the linear rate of 1.8 μM min⁻¹. Although, all the carotenoids tested at 1 mol % relative to EYPC retarded (p < 0.05) the chain propagation reaction of PCOOH formation α-carotene had the highest activity but this was less than α-tocopherol. α-Tocopherol, α-carotene, β-carotene, lutein and zeaxanthin reduced PCOOH accumulation by 78, 65, 40, 60 and 43%, respectively. AMVN incubated with EYPC for 2 h induced the formation of TBARS compared to the control (p < 0.001). α-Carotene significantly suppressed the TBARS formation by 68% whilst β-carotene, lutein and zeaxanthin elicited 50, 64 and 53% reductions, respectively. α-Tocopherol retarded the TBARS formation by 80%. These results suggest that α-carotene, a carotenoid abundantly present in human diets, especially red palm oil, may better attenuate peroxyl radical-dependent lipid peroxidation than β-carotene in organic solution.     

Fourier transform infrared (FTIR) spectroscopy for analysis of extra virgin olive oil adulterated with palm oil

Fourier transform infrared (FTIR) spectroscopy has been developed for analysis of extra virgin olive oil (EVOO) adulterated with palm oil (PO). Measurements were made on pure EVOO and that adulterated with varying concentrations of PO (1.0–50.0% wt./wt. in EVOO). Two multivariate calibrations, namely partial least square (PLS) and principle component regression (PCR) were optimized for constructing the calibration models, either for normal spectra or its first and second derivatives. The discriminant analysis (DA) was used for classification analysis between EVOO and that adulterated with PO and the other vegetable oils (palm oil, corn oil, canola oil, and sunflower oil). Frequencies at fingerprint region, especially at 1500–1000 cm^?1, were exploited for both quantification and classification. Either PLS or PCR at first derivative spectra revealed the best calibration models for predicting the concentration of adulterated EVOO samples, with coefficient of determination (R²) of 0.999 and root mean standard error of cross validation (RMSECV) of 0.285 and 0.373, respectively. DA was able to classify pure and adulterated samples on the basis of their FTIR spectra with no misclassified group obtained. In addition, DA was also effective enough to classify EVOO samples as the distinct group from the evaluated other vegetable oils.     

Supercritical fluid extraction of β-carotene from crude palm oil using CO2

The aim of this study was to ascertain the influence of pressure, temperature and time on the supercritical fluid extraction of β-carotene from the crude palm oil. The operating conditions were shown as follows: pressures of 75, 125 and 175 bar, temperatures of 80, 100 and 120 °C and extraction time of 1, 3 and 5 h. The extracts were analyzed using UV spectroscopy at a wavelength of 450 nm. Then the experimental data was compared with the data obtained using a statistical method. The results from the model showed a good agreement with the experimental data. The results (obtained from the statistical model) demonstrate that a pressure of 140 bar, temperature of 102 °C and extraction time of 3.14 h are required to obtain optimum yield of β-carotene (1.028 × 10⁻²%) from the extraction process, however the maximum yield of the β-carotene (1.741 × 10⁻²%) was experimentally obtained at a pressure of 75 bar, temperature of 120 °C and extraction time of 1 h.     

UV-C irradiation as an alternative disinfection technique: Study of its effect on polyphenols and antioxidant activity of apple juice

Ultraviolet (UV-C) irradiation is a non-thermal disinfection method, effective against a range of bacteria and viruses, which is being considered as an alternative to pasteurization of fruit juices. The objective of this study was to investigate the effect of UV-C irradiation on the polyphenolic content and in-vitro total antioxidant activity of apple juice. UV irradiation doses ranging from 0 to 240 mJ·cm^− 2 were delivered to apple juice and polyphenols, sugars, in-vitro total antioxidant activity and total phenols were profiled. The results demonstrated that UV-C irradiation in apple juices at relevant commercial disinfection doses induced significant reduction in the concentrations of chlorogenic acid, phloridzin, and epicatechin (p < 0.05). The induced changes were relatively minor for the above mentioned polyphenols, except phloridzin (50% reduction) at 240 mJ·cm^− 2. Epicatechin concentrations were reduced significantly (p < 0.05), whereas increase in catechin concentration was observed with increase in UV-C exposure to 240 mJ·cm^− 2. There was a minor reduction in sugar (glucose and fructose) concentrations with increasing exposure levels from 0 to 40 mJ·cm^− 2 (p > 0.05). In contrast, a slight increase in sugar concentrations as increase in UV-C exposure after 40 mJ·cm^− 2 was observed. These changes were not significantly different from control. Total phenolic content was well retained regardless of the UV-C exposure for apple juice. In-vitro total antioxidant activity changed when UV-C exposure exceeded 40 mJ·cm^− 2, but remained unchanged at the maximum UV-C dose of 240 mJ·cm^− 2. These results suggested that UV-C irradiation could be an effective alternative to conventional thermal processing for production of high quality apple juice.Industrial RelevanceThis research paper provides scientific evidence of the potential for UV-C irradiation to achieve meaningful levels of disinfection while retaining important bioactive compounds (polyphenols) in apple juice. In-vitro antioxidant activity and individual polyphenols were well retained at commercially relevant doses of 40 mJ·cm^− 2. From a nutritional perspective, UV-C irradiation is an attractive food preservation technology and offers opportunities for horticultural and food processing industries to meet the growing demand from consumers for healthier food products. Therefore, UV-C irradiated foods could be sold at a premium price to their thermally-processed counterparts, as they have retained their fresh-like properties. This study would provide technical information relevant for commercialization of UV-C treatment of juices.     

Sensory evaluation of egg products and eggs laid from hens fed diets with different fatty acid composition and supplemented with antioxidants

Is the sensory quality of eggs influenced by adding vegetable lipids, animal and vegetable sources of n − 3 polyunsaturated fatty acids (n − 3 PUFA), and/or natural antioxidants to the hens diet? To answer this question three feeding experiments were conducted adding either palm butter, grape seed oil, flax seed oil, n − 3 PUFA such as flax seed and marine algae and the natural antioxidant rosemary to the hens diet. For each experiment a standard diet was used as control. The results suggested that vegetable lipids (palm butter, grape seed, flax seed), n − 3 PUFA (flax seed and marine algae) and rosemary may be used to hens fed diet without affecting the sensory properties of eggs.The sensory quality of eggs was evaluated on hard boiled, scrambled eggs and Madeira cake.In this work, we report the first sensory characterization of eggs and products containing eggs obtained from hens diet based on grape and algae plus vitamin E and rosemary extract.     

Proximate composition,cholesterol and fatty acids profile of canned sardines (Sardinella brasiliensis) in soybean oil and tomato sauce

Different brands of sardines canned in soybean oil and tomato sauce, that are commercialized in Brazil, had their proximate composition, cholesterol content and fatty acids composition analyzed. Protein contents were equivalent to the values found for sardines in natura, ranging from 19.8 to 24.4%. High variations of the total lipids content (5.30–16.8%) were verified; the highest levels were found for sardines canned in soybean oil. The cholesterol content ranged from 50.4 to 65.1 mg/100 g. The highest levels of essential C18:2n − 6 and C18:3n − 3 fatty acids were found in sardines canned in soybean oil. The EPA (C20:5n − 3) and DHA (C22:6n − 3) concentrations ranged from 5.39 to 15.1% and from 3.89% to 9.51%, respectively, and the highest levels were observed in sardines canned in tomato sauce.     

In search of confectionary fat blends stable to heat: Hydrogenated palm kernel oil stearin with sorbitan monostearate

The potential of sorbitan monostearate (SMS) addition to change the basic-crystal-structure of a confectionary fat blend (CFB) with the aim to enhance its heat resistance was investigated. The CFB used in this study was a blend of hydrogenated palm kernel oil stearin, lecithin, polyglycerol polyricinoleate (PGPR) and cocoa butter. Samples made with different proportions of SMS to CFB were prepared and the crystal structure, the melting behaviour, the crystal morphology and crystallization kinetics were studied. Heat resistance was evaluated using a temperature-variable rheological method. Powder X-ray diffraction (XRD) studies in the wide angle region (WAXS) revealed the presence of two crystalline polymorphs (α and β′) in all blends. While XRD studies in the small angle region (SAXS) revealed a shift in the CFB peak position upon addition of SMS. The presence of two polymorphic forms was confirmed by differential scanning calorimetry (DSC), while a third endotherm was evident when the amount of SMS present in the system was greater than 40%. Studies on the nucleation and crystallization kinetics showed that crystal nucleation and growth occurred in two stages: SMS appeared first followed by CFB. Iso-solid diagrams constructed from the melting profiles obtained from SFC-temperature measurements indicated monotectic solution behaviour between SMS and the CFB.The microstructure, as observed under polarized light, changed from small crystals for the CFB to needles for mixtures with 10% SMS, to spherulites for mixtures with 50% SMS, to clusters for mixtures containing between 80 and 100% SMS. Cryo-TEM showed nanoplatelet formation for the CFB and nano-blobs for SMS. The storage modulus (G′) for mixtures containing 25% SMS decreased from G′ = 1.72 10⁷ ± 4.60 10⁶ Pa at 20 °C to G′ = 3.24 10⁵ ± 2.15 10⁴ Pa at 40 °C. Thus, SMS addition to confectionery fats can provide heat resistance to the CFB.     

In-vitro mineral binding capacity of five fiber sources and their insoluble components for magnesium and calcium1

In-vitro binding of calcium (Ca) and magnesium (Mg) by total dietary fiber, hemicellulose A (HCL A), lignocellulose (LCL), cellulose (CL), and lignin (L) fractions isolated from rice bran (RB), wheat bran (WB), oat fiber (OF), apple fiber (AF) and tomato fiber (TF) was evaluated. At pH 6.8, significant amounts of Ca were bound by whole fibers, ranging from 800 μg g⁻¹ for RB to 10 097 μg g⁻¹ for TF. Mg bound by whole fibers varied from 496 μg g⁻¹ for OF to 2177 μg g⁻¹ for WB. Re-acid washing (pH<2.0) released 95–99% of the Ca and Mg bound to the fibers. Fibers with the highest endogenous Ca and Mg concentrations bound significantly (P<0.05) the highest amounts of the minerals studied. The Ca bound by HCL A varied from 9753 μg g⁻¹ for RB to 11 337 mg g⁻¹ for TF, whereas Mg bound varied from 1151 μg g⁻¹ for OF to 5626  μg g⁻¹ for TF hemicellulose fractions, respectively. Among the fiber components, Mg binding decreased in the order HCL A>LCL>L>CL, whereas Ca bound was in the order HCL A>LCL>CL>L. A relatively strong correlation was observed between the combined effects of protein content, hemicellulose, and lignin vs total Ca and Mg bound. 1998 Elsevier Science Ltd. All rights reserved     

Aluminium in foodstuffs

The aluminium content of a comprehensive food assortment typical of German nutritional habits was determined within the framework of market basket studies. Carried out in 1988 and 1991, a total of 128 items out of 12 groups of foodstuffs were included in this investigation. Aluminium content of the food assortment was low and comparable with literature data. Most investigated foodstuffs contained <5 μg Al g⁻¹ FM. Highest concentrations were determined in cocoa/cocoa products (33 μg g⁻¹), spices (145 μg g⁻¹) and black tea leaves (899 μg g⁻¹). In general, aluminium content of frequently consumed food, increased in the following order: beverages, food of animal origin, food of plant origin. With this low level of aluminium concentration in food, there is no danger of aluminium exposure in healthy persons.     

Identification and quantification of phenolic compounds in kernels,oil and bagasse pellets of common walnut (Juglans regia L.)

Individual phenolic compounds, total phenolic content and antioxidant potential were assessed in kernels, oils and bagasse pellets (residues of oil pressing) of different walnut cultivars. Twenty-seven phenolic compounds were detected in kernels and pellets conducting high-performance liquid chromatography–tandem mass spectrometry. The main polyphenolic subclass comprised hydrolysable tannins, which accounted approximately 60.80% (kernels) and 61.66% (pellets) of the total phenolics identified (TPI). Walnut oil was poor in phenolics and contained only six different compounds but due to their low content (from 0.15 to 1.44 μg g^− 1) just two compounds have been identified. Glansreginin A and glansreginin B were detected in all analyzed walnut products. A comparison of average amount of total phenolic content revealed that walnut oil contains as much as 154 fold less phenolics (0.05 mg GAE g^− 1 FW) compared to kernels (7.7 mg GAE g^− 1 FW) or pellets (7.9 mg GAE g^− 1 FW).     

Phenolic profile and antioxidant activity of the Algerian ripe date palm fruit (Phoenix dactylifera)

The aim of this study was to determine the phenolic profile of seven different varieties of ripe date palm fruit (Phoenix dactylifera) from Algeria by LC–DAD–MS (ESI+), to investigate their respective antioxidant activities by the DPPH^· method and to estimate their phenolic content using the Folin–Ciocalteu method. The total phenolic content was in the range of 2.49 ± 0.01 to 8.36 ± 0.60 mg gallic acid equivalents (GAE) per 100 g fresh fruit. This fruit was shown to possess an antioxidant activity, giving values of antiradical efficient (AE) from 0.08 ± 0.00 to 0.22 ± 0.00. The phenolic contents and the antiradical efficiencies of the different varieties were highly correlated (R²=0.975). All the varieties were found to contain mainly p-coumaric, ferulic and sinapic acids and some cinnamic acid derivatives. Three different isomers of 5-o-caffeoylshikimic acid were detected. Different types of flavonoids were identified, mainly flavones, flavanones and flavonol glycosides.     

Production of conjugated linoleic acid enriched milk and dairy products from cows receiving grass silage supplemented with a cereal-based concentrate containing rapeseed oil

Opportunities for the production of milk and dairy products enriched with cis-9, trans-11 conjugated linoleic acid (CLA) were investigated. Eighteen mid-lactation cows were used in a continuous-design for 7 weeks. During the first week, cows received grass silage ad libitum supplemented with 10 kg per day of a cereal-based concentrate (control) that was replaced with a concentrate containing 50 g kg⁻¹ of rapeseed oil (RO). Changes in milk fatty acid composition were monitored on a weekly basis and milk produced was used to manufacture Edam cheese and butter. Inclusion of RO in the concentrate supplement increased the mean levels of trans-octadecanoic, monounsaturated, CLA and polyunsaturated fatty acid in the milk fat from 1.6, 25.7, 0.46 and 2.8 to 4.3, 35.3, 1.02 and 3.9 g 100 g⁻¹ total fatty acids, respectively. In contrast, the mean level of saturated fatty acids decreased from 71.4 to 60.7 g  100 g⁻¹ total fatty acids. Changes in milk fatty acid composition due to RO occurred within 7 days, with responses reaching a plateau after 21 days. Furthermore, the CLA concentrations in the milk fat from individual cows ranged between 0.37 and 0.65 and 0.43 and 2.06 g 100 g⁻¹ total fatty acids for the control and RO diet, respectively. CLA enriched milk was used successfully to manufacture of Edam cheese and butter with softer textures but with acceptable organoleptic and storage properties. Processing milk into butter or cheese had no effect on the CLA concentrations indicating that enrichment of dairy products is dependent on the content in raw milk fat.     

In situ crystallization and transformation kinetics of polymorphic forms of saturated-unsaturated-unsaturated triacylglycerols: 1-palmitoyl-2,3-dioleoyl glycerol, 1-stearoyl-2,3-dioleoyl glycerol,and 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol

We examined the influence of dynamic thermal treatment (variation of cooling/heating rates) on the polymorphic crystallization and transformation pathways of 1-palmitoyl-2,3-dioleoyl glycerol (POO), 1-stearoyl-2,3-dioleoyl glycerol (SOO), and 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol (POL), which are major saturated-unsaturated-unsaturated (SUU) triacylglycerols (TAGs) of vegetable oils and animal fats (e.g., palm oil, olive oil, and Iberian ham fat). Using mainly a combination of differential scanning calorimetry (DSC) and synchrotron radiation X-ray diffraction (SR-XRD), we analyzed the polymorphic behavior of TAGs when high (15 °C min^− 1), intermediate (2 °C min^− 1), and low (0.5 °C min^− 1) cooling and heating rates were applied. Multiple polymorphic forms were detected in POO, SOO, and POL (sub-α, α, β’₂, and β’₁). Transient disordered phases, defined as kinetic liquid crystal (KLC) phases, were determined in POO and SOO for the first time. The results demonstrated that more stable forms were directly obtained from the melt by decreasing the cooling rates, whereas less stable forms predominated at high cooling rates, as confirmed in our previous work. Regarding heating rate variation, we confirmed that the nature of the polymorphic transformations observed (solid-state, transformation through KLC phase, or melt-mediation) depended largely on the heating rate. These results were discussed considering the activation energies involved in each process and compared with previous studies on TAGs with different saturated-unsaturated structures (1,3-dioleoyl-2-palmitoylglycerol, 1,3-dipalmitoyl-2-oleoyl-glycerol, trioleoyl glycerol, and 1,2-dioleoyl-3-linoleoyl glycerol).     

Stability of emulsions formulated with high concentrations of sodium caseinate and trehalose

Stability of emulsions formulated with 10 wt.% oil (concentrated fish oil, CFO, sunflower oil, SFO, or olive oil, OO), sodium caseinate concentrations varying from 0.5 to 5 wt.%, giving oil-to-protein ratios of 20–2, and 0, 20, 30 or 40 wt.% aqueous trehalose solution was studied by Turbiscan. Particle size distribution, microstructure, and small angle X-ray scattering (SAXS) patterns were also obtained. The main mechanism of destabilization in a given formulation strongly depended on oil-to-protein ratio. As evidenced by the BS-profile changes with time, emulsions formulated with 0.5 and 1 wt.% NaCas destabilized mainly by creaming while for the 2 wt.% NaCas concentration, both creaming and flocculation mechanisms, were involved. The main destabilization mechanism for the 3, 4 or 5 wt.% NaCas emulsions was flocculation. Stability of emulsions was also affected by the content of trehalose in the aqueous phase. Trehalose diminished the volume-weighted mean diameter (D_4,3) and greatly improved stability.     

Comparison of the effect of pulsed electric field or high voltage electrical discharge for the control of sweet white must fermentation process with the conventional addition of sulfur dioxide

The present work discusses the efficiency of pulsed electrical treatments for the inactivation of yeasts. The application of pulsed electric fields (PEFs) and high voltage electrical discharges (HVEDs) as alternatives to sulfites, which are used as anti-microbial to stop the fermentation of sweet white wine, was investigated. The influence of sulfite concentration (from 0 mg·L^− 1 to 500 mg·L^− 1), PEF (from 4 kV·cm^− 1 to 20 kV·cm^− 1; from 0.25 ms to 6 ms) and HVED (40 kV/cm; 1 ms or 4 ms) treatments on the inactivation of total yeasts and non-Saccharomyces yeasts was determined. The addition of SO₂ (250 mg·L^− 1) resulted in 8 log total yeast reduction. The maximum yeast inactivation obtained with PEF and HVED was respectively 3 and 4 logs. The use of SO₂, HVED and PEF allows decreasing the non-Saccharomyces yeast level by 7, 5 and 4 logs respectively. However, the wine browning was less pronounced for the samples treated by PEF in comparison with HVED and SO₂ treatments. PEF seems to be the most suitable alternative technique to sulfite addition.     

Immunoglobulins,growth factors and growth hormone in bovine colostrum and the effects of processing

In colostrum collected 0–80 h postpartum the contents of immunoglobulins (Igs), transforming growth factor beta-2 (TGF-β2), insulin-like growth factor-1 (IGF-1) and growth hormone (GH) were analysed. Colostrum initially contained 90 mg mL⁻¹ IgG1, 2.8 mg mL⁻¹ IgG2, 1.6 mg mL⁻¹ IgA, 4.5 mg mL⁻¹ IgM, and these concentrations declined by 92%, 87%, 93% and 84%, respectively, in the samples collected later. Of the growth factors, colostrum initially contained 289–310 ng mL⁻¹ TGF-β2 and the concentration diminished to 66 ng mL⁻¹. The content of IGF-1 and GH postpartum decreased from 870 to 150 ng mL⁻¹, and from 0.17 to <0.03 ng mL⁻¹, respectively. Heat treatment and freeze-drying of colostral whey decreased the content of Igs to 75%, while the contents of IGF-1 and TGF-β2 were unaffected. A similar processing, including filtration steps reduced also the IGF-1 and TGF-β2 by 25%. IgM seems to be the most sensitive of the Igs to processing.