Estimation of somatic cell count levels of hard cheeses using physicochemical composition and artificial neural networks.

This study addresses the prediction of the somatic cell counts of the milk used in the production of sheep cheese using artificial neural networks. To achieve this objective, the neural network was designed using 33 parameters of the physicochemical composition of the cheeses obtained after they have been matured for 12 mo as input data. The physicochemical analysis of the cheeses revealed that the somatic cell count level of the cheese has a significant influence on the amount of protein, fat, dry extract, and fatty acids. When properly set up, the neural network allows the correct classification of the cheeses (100% of correct results in both training and test phases) and therefore their samples in each of the 3 nominal output variables (low, average, and high somatic cell counts). The fatty composition of the cheeses, individual fatty acids, and fat acidity are the variables that most affect the correct operation of the neural network.

Pesticide residues in propolis from Spain and Chile. An approach using near infrared spectroscopy.

This study analyses the presence of pesticides in 106 samples of raw propolis from Spain and Chile. The components detected and quantified using gas chromatography mass spectrometry were as follows: triamidefon present in 70.1% of the samples with concentrations between 0.35 and 42.17mg/kg, and dicofol detected in 7.5% of the samples with concentrations between 0.39 and 2.83mg/kg. Diclorofluanid, procymidone, folpet, propham and metazachlor were also detected but only in a small number of samples. Near infrared spectroscopy with a remote reflectance fibre-optic probe was used to detect samples contaminated with triadimefon via partial least squares discriminant, with a R2 value of 0.71. In addition, the presence of the pesticide triadimefon in propolis was quantified using the modified partial least squares (MPLS) regression method. The calibration results showed a coefficient of determination (R2) of 0.81, a root mean square error (RMSE) of 0.36, and a ratio of performance to deviation (RPD) of 2.5.

Antioxidant capacity of different cheeses: Affecting factors and prediction by near infrared spectroscopy.

In this study, we analyzed antioxidant capacity of 224 cheese samples prepared using 16 varied mixtures of milk from cows, ewes, and goats, in 2 manufacturing seasons (winter and summer), and over 6mo of ripening. Antioxidant capacity was evaluated using the spectrophotometric 2,2-azinobis(3-ethylenebenzothiazoline-6-sulfonic acid) (ABTS) method. Total antioxidant capacity was significantly correlated with season of manufacturing and time of ripening but not with animal species providing the milk. Moreover, statistically significant correlations between the total antioxidant capacity and retinol (r=0.399), fat percentage (r=0.308), protein percentage (r=0.366), K (r=0.385), Mg (r=0.312), Na (r=0.432), and P (0.272) were observed. We evaluated the use of near infrared spectroscopy technology, together with the use of a remote reflectance fiber-optic probe, to predict the antioxidant capacity of cheese samples. The model generated allowed us to predict antioxidant capacity in unknown cheeses of different compositions and ripening times.

Evaluation of the effect of a maternal rearing system on the odour profile of meat from suckling lamb.

The aim was to evaluate the effect of maternal rearing system on the chemical composition and odour profile of meat from suckling lamb. Twenty-four single male suckling lambs raised exclusively on maternal milk came from two rearing systems (extensive and intensive), and from Castellana and Churra breeds. The fatty acid composition of lamb meat from both breeds was affected by the rearing system, and Churra lamb reared under the extensive system had noticeable changes in odour attributes as detected by panellists and an electronic nose. Using partial least squares-discriminant analysis, the electronic nose was able to discriminate accurately between samples of Churra and Castellana meat according to their production system. However, it was not able to correctly classify meat samples from the extensive and intensive systems when both breeds were analysed together. The results suggest a significant effect of the rearing system and breed on suckling lamb meat quality traits.

Effect of the addition of calcium soap to ewes' diet on fatty acid composition of ewe milk and subcutaneous fat of suckling lambs reared on ewe milk.

The aim of this work was to study the effect of the inclusion of calcium soap (CS) in ewes' diet on the fatty acid profile of suckling lambs. Sixty suckling lambs of three breeds (Castellana, Churra and Assaf) were divided into two equal groups. One group was fed with a diet composed of beetroot pulp, alfalfa, barley, corn, soy, cotton and 4% of CS, and the other with a control diet without CS. The fatty acid profiles of the ewe's milk samples collected on the day before slaughter and of the lamb subcutaneous fat collected from the back of the carcasses were analysed. The addition of calcium soap to the ewe's diet did not change the milk fatty acid profile but significantly increased SFA and decreased both the PUFA and MUFA levels of suckling lamb fat. PCA analysis revealed a good separation of the lamb samples according to the diet of the mothers, showing that diet is more important than breed in explaining sample variability.

Influence of somatic cell count and breed on capillary electrophoretic protein profiles of ewes' milk: a chemometric study.

Bulk tank ewe milk from the Assaf, Castellana, and Churra breeds categorized into 3 somatic cell count (SCC) groups (<500,000; 1,000,000 to 1,500,000; and >2,500,000 cells/mL) was used to investigate changes in chemical composition and capillary electrophoresis protein profiles. The results obtained indicated that breed affected fat, protein, and total solids levels, and differences were also observed for the following milk proteins: beta-, beta1-, beta2-, and alpha(s1)-III-casein, alpha-lactalbumin, and beta-lactoglobulin. High SCC affected fat and protein contents and bacterial counts. The level of beta1-, beta2-, and alpha(s1)-I-casein, and alpha-lactalbumin were significantly lower in milk with SCC scores >2,500,000 cells/mL. A preliminary study of the chemical, microbiological, and electrophoretic data was performed by cluster analysis and principal components analysis. Applying discriminant analysis, it was possible to group the milk samples according to breed and level of SCC, obtaining a prediction of 100 and 97% of the samples, respectively.

Effect of breed and ageing time on meat quality and sensory attributes of veal calves of the "Ternera de Aliste" Quality Label.

The effect of breed, sex and ageing time on carcass, meat and eating quality were examined in 32 calves of the "Ternera de Aliste" Spanish Quality Label. Swiss Brown×Alistano-Sanabresa heifers were mated with Charolais or Limousin bulls in order to study the effect of breed. Bull and heifer calves were slaughtered when they were 6-7 months old. Samples of the M. longissimus dorsi were aged for 3, 5 or 7 days and chemical and sensory analyses were done. The results showed no differences due to sex but Charolais sires produced meat which was more tender, juicier and had more odour intensity with a darker colour than meat of the Limousin sired animals. Ageing influenced both sensory and instrumental hardness, colour and odour intensity. After seven days of maturation the meat from such young animals achieved a high quality.

Determination and evaluation of the parameters affecting the choice of veal meat of the "Ternera de Aliste" quality appellation.

The aim of the present work was to determine and assess the parameters affecting the choice of veal under the "Ternera de Aliste" quality appellation. The parameters affecting the choice proved to be colour, taste, odour, hardness and juiciness. Using these parameters, sensory evaluation, both analytical (with trained judges, QDA) and affective (with consumers, the home-use test) was carried out on four veal types, and the relative preferences for the samples assessed. Colour, hardness and losses due to cooking were also analysed instrumentally. The results revealed that the methodology is important for discriminating small differences between samples. The same trend was observed for the results of the panel of judges, consumers, and instrumental analyses regarding both hardness and juiciness. Regarding the determinant parameters in the choice of veal, in raw meat consumers prefer light colours but when expressing their general relative preferences for samples, juiciness, taste and hardness of the cooked meat had the greatest weight.

Effect of locust bean/xanthan gum addition and replacement of pork fat with olive oil on the quality characteristics of low-fat frankfurters.

The effects of reducing fat level from 20% to 12% and 9%, substituting pork fat with olive oil and adding locust bean/xanthan gum (0.5% and 0.6%) on emulsion stability, jelly and fat separation, processing yield, cook loss, texture and sensory characteristics of frankfurters were investigated and compared with control samples. Addition of locust bean/xanthan gum produced a significant increase in hydration/binding properties, characterised by lower cook losses, increasing yield, better emulsion stability and lower jelly and fat separation. The substitution of pork fat by olive oil did not affect these parameters. Indeed, results showed that reducing fat levels together with increasing moisture and locust bean/xanthan gum addition do not affect the sensory or textural properties, but olive oil addition produces a decrease in hardness and an increase in adhesiveness, however the overall acceptability was not affected.