Identification and differentiation of goat and sheep milk based on diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) using cluster analysis

A new methodology for identification and differentiation of goat and sheep milk was developed based on FT-IR spectroscopy using hierarchical and discriminant analysis. Forty-nine goat and 38 sheep defatted and freeze-dried Greek milk samples were analyzed. FT-IR spectra were obtained in the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) mode. The spectral region 1840–950 cm⁻¹ was used to ‘fingerprint’ milk types. Main peak used for differentiation of goat/sheep milk is located at 1745 cm⁻¹, which is correlated to the degree of sugars carboxyl methyl esterification. Hierarchical and discriminant analyses were based on the absorptions of the above spectral region. These analyses showed that the samples of goat milk can be differentiated from the samples of sheep’s.     

Effect of high-pressure treatment at various temperatures on indigenous proteolytic enzymes and whey protein denaturation in bovine milk

The objective of the present study was to determine the effect of high pressure (HP) processing (200, 450 and 650 MPa) at various temperatures (20, 40 and 55 degrees C) on the total plasmin plus plasminogen-derived activity (PL), plasminogen activator(s) (PA) and cathepsin D activities and on denaturation of major whey proteins in bovine milk. Data indicated that transfer of both PL and PA from the casein micelles to milk serum occurred at all pressures utilized at room temperature (20 degrees C). In addition to the transfer of PL and PA from micelles, there were reductions in activities of PL (16-18%) and PA (38-62%) for the pressures 450 and 650 MPa, at room temperature. There were synergistic negative effects between pressure and temperature on residual PL activity at 450 and 650 MPa and on residual PA activity only at 450 MPa. Cathepsin D activity in the acid whey from HP-treated milk was in general baroresistant at room temperature. The residual activity of cathepsin D decreased significantly at 650 MPa and 40 degrees C and at the pressures 450 and 650 MPa at 55 degrees C. Synergistic negative effects on the amount of native beta-lactoglobulin were observed at 450 and 650 MPa and on the amount of native alpha-lactalbumin at 650 MPa. There were significant correlations between enzymatic activities (PL, PA and cathepsin D) and the residual native beta-lactoglobulin and alpha-lactalbumin in bovine milk. In conclusion, HP significantly affected the activity of indigenous proteolytic enzymes and whey protein denaturation in bovine milk. Reduction in activity of indigenous enzymes (PL, PA and cathepsin D) and transfer of PL and PA from the casein to milk serum induced by HP is expected to have a profound effect on cheese yield, proteolysis during cheese ripening and quality of UHT milk during storage.     

Application of high-pressure treatment on ovine brined cheese: Effect on composition and microflora throughout ripening

Ovine brined cheese was high-pressure (HP) treated at 200 or 500 MPa for 15 min at 20 °C on the 15th day of ripening. Compared to control cheese, HP treatment did not affect significantly (P > 0.05) the pH values, moisture, fat in dry matter, protein in dry matter and salt in moisture contents of cheeses at 90 days. The counts of total aerobic mesophilic bacteria, thermophilic lactococci, thermophilic lactobacilli and non starter lactic acid bacteria (NSLAB) were not affected by HP treatment of cheese at 200 MPa throughout ripening. After 90 days of ripening, the same microbial groups in cheese treated at 500 MPa were about 1.2, 3.6, 2.1 and 4 log units lower than in control cheese respectively. Coliforms were reduced faster at non detectable levels in HP treated cheeses than in control cheese. Regarding the bacterial enzymatic activities in cheese, aminopeptidase activity (Apep) was marginally favoured by both HP treatments. However, its activity was decreased at 90 days due probably to loss in brine. In contrast, lactate dehydrogenase (LDH) activity, following the bacteria cell lysis, was negatively affected by HP treatment at 500 MPa throughout ripening.Industrial relevanceThe data obtained from this work suggest that application of HP treatment under optimized conditions on ovine cheese in brine can be used to reduce effectively the undesirable microbial load in it and to cause moderate enhancement of aminopeptidase activity, without modifying its composition.     

Direct determination of lactulose in heat‐treated milk using diffuse reflectance infrared Fourier transform spectroscopy and partial least squares regression

The aim of this work was the direct determination of lactulose (LCT) concentration in freeze‐dried heat‐treated milks using diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) without any chemical pretreatment of the milk. The ‘actual’ lactulose concentrations estimated by means of high‐performance liquid chromatography (HPLC) were correlated with the spectral region 1286–754 cm^?1 of DRIFTS spectra in the second‐derivative form of the milk samples using partial least squares (PLS) regression. A linear relationship was established between the ‘actual’ and the concentrations recalculated using the built model. The proposed DRIFTS method is simple, rapid and low cost.     

Methadone maintenance improves cognitive performance after two months of treatment.

Methadone maintenance (MM) has received little scientific attention regarding neurocognitive effects. The present study examined cognitive function in 17 opiate-dependent subjects at baseline and after 2 months of MM treatment. Subjects demonstrated significant improvements from baseline on measures of verbal learning and memory, visuospatial memory, and psychomotor speed and reduced frequency of drug use (Addiction Severity Index) relative to baseline, although the total percentage of urine samples positive for additional illicit substances was slightly increased. No effect of illicit drug use was observed when the sample was stratified by urine toxicology results, suggesting that improvements in cognition were not associated with additional illicit drug use. Results suggest that opiate-dependent subjects exhibit significant improvement in cognitive function after MM treatment. Future investigations are needed to confirm these findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recent developments in antibody-based analytical methods for the differentiation of milk from different species

The antibody-based analytical methods for the detection of milk from different species that have been developed in recent years are, for the most part, various enzyme-linked immunosorbent assay (ELISA) configurations. Polyclonal and, more recently, monoclonal antibodies against total or individual caseins, whey proteins and synthetic peptides corresponding to milk proteins sequences have been used. The assays have been successfully applied to the detection of substitution of ovine or caprine milk by bovine milk and of ovine milk by caprine milk in raw and heat-treated milks and cheeses.     

Effect of supplementation of brine with calcium on the Feta cheese ripening

Feta blocks ripened in plain or calcium‐supplemented brine were analysed with respect to biochemical characteristics, proteolysis and inorganic fractions; moreover, the inorganic and N content of the respective brines was estimated. The acidification of Feta in supplemented brine was faster, the moisture content was lower, secondary proteolysis was more extended, and the organoleptic scores were higher compared to control Feta ripened in plain brine. The TCASN fraction of cheeses contributed more than that of WSN to the N enrichment of brine. It was concluded that calcium supplementation of the brine retarded the diffusion of cheese N and Ca into the brine.     

Predicting cocaine group treatment outcome in cocaine-abusing methadone patients.

The authors examined predictors of cocaine group treatment outcome in methadone maintenance treatment (MMT) patients, including cocaine urinalysis at intake and demographic variables. Clinic policy is that patients identified as using cocaine must attend a weekly cocaine-focused, cognitive–behavioral therapy (CBT) group. Cocaine treatment is based on a behavioral (escape) contingency model whereby completers must attend group-counseling sessions and produce cocaine-negative urinalysis results. Among the 113 patients enrolled in the cocaine group, 43 (38%) were treatment completers (who attended 6 consecutive weeks of group and produced 6 consecutive weeks of cocaine-free urine tests) and 70 (62%) were treatment noncompleters. Treatment completion (i.e., cocaine abstinence) was significantly associated with baseline cocaine-free urinalysis and higher methadone dose. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of technological parameters on the characteristics of kasseri cheese made from raw or pasteurized ewes' milk

Two groups of kasseri cheese (pasta filata type) were manufactured from raw or pasteurized ewes' milk, without starter cultures. Cheeses of each group were divided into two subgroups: the first was ripened and stored at 4°C and packaged in plastic film; the second ripened and stored at 15°C and coated with paraffin wax. Milk pasteurization and technological parameters had a significant effect on the pH ( P  < 0.05), while only technological parameters had an effect on the total solids content. At day 120, the range of mean cfu/g counts for the mesophilic aerobic flora was 9.5 × 10⁷−1.4 × 10⁸; for the thermophilic streptococci, the range was 2.6 × 10⁷−7.6 × 10⁷; and for the thermophilic bacilli, 9.8 × 10⁶−1.7 × 10⁷. Changes in the N fractions became significant after 30 days of ripening. For mature 120-day-old cheeses, the percentage of total N soluble at pH 4.6 was 22.7%–22.9% in raw milk cheeses and 19.0%–21.7% in pasteurized milk cheeses. The percentage of total N soluble at 12% TCA was 10.1%–12.2% in raw milk cheeses and 7.3%–11.5% in pasteurized milk cheeses; the percentages of total N soluble at 5% PTA were 3.1%–4.0% and 2.6%–3.6%, respectively. The residual α_s-casein percentages at day 120 ranged between 63% and 78% of the respective area at day 1; the residual β-casein ranged between 67% and 75%. There were some characteristic differences in the reverse phase-HPLC peptide profiles of the four cheeses. In general, the effect of the different ripening conditions was more pronounced in cheeses made from pasteurized milk.     

Comparative study of the protein fraction of goat milk from the Indigenous Greek breed and from international breeds

Individual goat milk samples, taken from animals of the Indigenous Greek breed and from the international breeds Saanen and Alpine, were studied by RP-HPLC regarding the qualitative and quantitative characteristics of their proteins. Thirty-two samples from the Indigenous Greek breed and 17 from the international breeds were characterised further by RP-HPLC/ESI-MS. The mean total protein content of the milk samples from the Greek breed was higher 38.8 g/l, compared to 31.9 g/l of those from international breeds, due to the great difference between their mean αs1-Cn contents (6.90 and 3.02 g/l, respectively). In the milk samples of the Greek breed, the strong αs1-Cn variants B3, B4 and As/B1 predominated, whereas in the milk samples from international breeds the medium variant E and the defectives F and null predominated. Variant A of αs2-Cn followed by variant C and the κ-Cn D (former B) were the most abundant in both groups. αs2-Cn F and the rare κ-Cn variant C/B were observed in the milk samples from the Greek breed. The β-caseins A and C were present in both groups of samples. Finally, the level of phosphorylation of the different genotypes is showed.