Simultaneous Determination of Alpha-Tocopherol and Alpha-Tocopheryl Acetate in Dairy Products,Plant Milks and Health Supplements by Using SPE and HPLC Method

A solid phase extraction technique for sample cleanup and extraction of α-tocopherol and α-tocopheryl acetate is described and applied to their simultaneous HPLC analysis in dairy products, plant-based milks, infant formulas, and pharmaceutical colostrum. The proposed method includes sample pretreatment by using ethanol, followed by solid-phase extraction of the organic supernatant on C18 cartridges. The identification and quantification were done by reversed-phase HPLC with fluorescence detection (ex 295 nm, em 330 nm) for tocopherol and with UV detector set at 220 nm for tocopheryl acetate. The mobile phase consisted of 100% acetonitrile. The linear ranges were from 0.02–0.40 μg/mL (dairy products) and 0.50–5.00 μg/mL (plant milks, infant formulas, powdered products) for α-tocopherol and those of α-tocopheryl acetate were from 0.20–2.00 μg/mL (dairy products) and 1.00–10.0 μg/mL (plant milks, infant formulas, powdered products). The LOD and LOQ of α-tocopherol were 0.1 and 0.4 μg/mL, while those of the α-tocopheryl acetate were 2.0 μg/mL for LOD and 6.0 μg/mL for LOQ. The method gave extraction recoveries from 73–94% with RSDs values being 5–10%. This method is simple, SPE procedure is fast and HPLC analysis time is less than 10 min. The total time of performing analysis per sample is less than 1 h. The important advantage of the proposed method is the capability of determining and reporting α-tocopherol and α-tocopheryl acetate separately. Moreover, the developed method is suitable for fast screening of the synthetic form of vitamin E in dairy products, plant-based milks, infant formulas, and pharmaceutical colostrum.     

Development of Quality Index Method (QIM) scheme for Acoupa weakfish (Cynoscion acoupa)

A Quality Index Method (QIM) scheme for gutted and iced Acoupa weakfish (Cynoscion acoupa) was developed and its efficiency for freshness evaluation was compared with instrumental colour analysis, microbial and chemical methods. The QIM scheme comprises sensory evaluation of 14 parameters, reaching a total sum of 23 demerit points. The evolution of Quality Index (QI) was identical in two independent storage experiments and could be represented by the equation QI = 1.3593 × days − 0.3822 (R² = 0.9614, P < 0.0001). The QIM results indicated a shelf life of 8–9 days, when the sensory quality was considered unacceptable. The storage time affected a∗ and b∗ values for fish gill and caudal fin, respectively. Psychrotrophic bacteria counts (PBC) increased at different rates during the iced storage of fish in three independent storage experiments, reaching the maximum recommended limit for marginally acceptable quality products of 10⁷ CFU/g between 6 and 14 days. The shelf life of Acoupa weakfish estimated by QIM was slightly longer than that evaluated by PBC. The rate and pattern of total volatile base nitrogen and trimethylamine production was different in fish from three independent storage experiments. The use of QIM scheme was a reliable way of assessing freshness of Acoupa weakfish.     

Use of mild irradiation doses to control pathogenic bacteria on meat trimmings for production of patties aiming at provoking minimal changes in quality attributes

The objectives of the present work were to assess the use of moderate doses of gamma irradiation (2 to 5 kGy) and to reduce the risk of pathogen presence without altering the quality attributes of bovine trimmings and of patties made of irradiated trimmings. Microbiological indicators (coliforms, Pseudomonas spp and mesophilic aerobic counts), physicochemical indicators (pH, color and tiobarbituric acid) and sensory changes were evaluated during storage. 5 kGy irradiation doses slightly increased off flavors in patties. Two pathogenic markers (Listeria monocytogenes and Escherichia coli O157:H7) were inoculated at high or low loads to trimming samples which were subsequently irradiated and lethality curves were obtained. Provided that using irradiation doses ≤ 2.5 kGy are used, reductions of 2 log CFU/g of L. monocytogenes and 5 log CFU/g of E. coli O157:H7 are expected. It seems reasonable to suppose that irradiation can be successfully employed to improve the safety of frozen trimmings when initial pathogenic bacteria burdens are not extremely high.     

Nutraceutical intervention with colostrum replacer: Can we reduce disease hazard,ameliorate disease severity,and improve performance in preweaned dairy calves?

The objective of this randomized clinical trial was to determine if an intervention with colostrum replacer (CR; Premolac Plus, Zinpro; 125 g/d fed for 3 d) or a placebo milk replacer (Cows Match, Land O'Lakes Inc.; 125 g/d for 3 d) following a triggered alarm could ameliorate disease bouts in dairy calves. The alarm was set to detect negative deviations of milk intake (20% reduction) or drinking speed (30% reduction) in relation to a calf's 12-d rolling average feeding behavior. Calves were enrolled on this study (n = 42 CR, n = 42 placebo) when they triggered an alarm from d 14 to 50 on the feeder before weaning. Once calves were enrolled, calves received a bottle of either 125 g of CR or milk replacer mixed with 1 L of water for 3 d. Calves were enrolled on the automated milk feeder at age 4.0 ± 2.0 d (mean ± SD), were offered 10 L/d of the same milk replacer fed as a placebo, and had ad libitum access to calf starter measured by automated feeders. Weaning began at d 50, with 50% reduction of milk replacer across 14 d, and an additional 20% reduction for another 7 d before weaning at d 70. Calves were health scored from birth to 2 wk postweaning (88 ± 2.0 d of age) daily for bovine respiratory disease (BRD) and diarrhea, and were weighed and scored using lung ultrasonography twice weekly. A BRD score ≥5 and an area of consolidated lung ≥3.0 cm² was considered BRD positive; diarrhea was defined as a watery fecal consistency that sifted through the bedding. The effect of CR on BRD and diarrhea likelihood were calculated with logistic models; the 7 d before and after an alarm were fixed effects, with milk intake as a covariate. A Cox proportional hazards model evaluated the effect of CR on the hazard of being positive for BRD and diarrhea following enrollment, with sex as a fixed effect in the diarrhea model. The effect of CR on average daily gain the week following intervention was evaluated with linear modeling with repeated measures, and birth date was a random effect. After intervention, placebo calves had 1.64 (95% CI: 1.11–2.43) times greater odds of having a BRD bout compared with CR calves for the 7 d following intervention. Moreover, placebo calves had 1.50 (95% CI: 1.11–2.08) times greater odds of having lobar lung consolidation in the 7 d after intervention than CR calves. No difference was found in the likelihood of diarrhea in the 7 d after intervention (odds ratio: 0.91; 95% CI: 0.71–1.16). However, placebo calves had a 2.38 (95% CI: 1.30–4.33) times greater hazard of incurring BRD in the 14 d after intervention. Average daily gain was not associated with an intervention with CR for the 7 d after intervention (placebo: 0.73 ± 0.07 kg/d; CR: 0.70 ± 0.08 kg/d; LSM ± SEM). These results suggest CR may reduce BRD likelihood but did not influence growth in calves offered high allowances of milk. Future research should examine which properties of CR ameliorate BRD in calves.     

Effect of a cold‐active pectinolytic system on colour development of Malbec red wines elaborated at low temperature

The effect of a new cold‐active pectinolytic system on colour of Malbec wines was studied under the following winemaking conditions: (i) fermentation at low temperature (20 °C) and (ii) prefermentative cold maceration (PCM) (5 °C–7 days) followed by traditional fermentation (28 °C). The pectinolytic system was mainly composed of polymethylgalacturonase and pectin lyase activities, detected under similar conditions to those in winemaking (pH 3.6–20 °C). The results show that the enzyme system significantly accelerated colour extraction by reducing the maceration time necessary for vinification at low temperature and shortening the PCM stage. Enzyme‐treated wines exhibited better chromatic parameters than their controls at devatting and after 6 months of storage. The cold‐active enzyme compensated the decrease in colour extraction due to the low maceration temperature, achieving high‐quality wines with chromatic characteristics similar to those of traditional wines.     

A new vinylpyranoanthocyanin pigment occurring in aged red wine

A new pyranoanthocyanin–vinylphenol pigment was detected in an aged Port red wine. The UV–Vis spectrum of this pigment was found to have a λ_max of 538 nm that is bathochromically shifted from that of original anthocyanins, exhibiting a more purple hue in acidic solution. This newly formed pigment was synthesized in model solution through the reaction between malvidin 3-O-glucoside–pyruvic acid adduct and vinylphenol and its structure was assigned by NMR and mass spectrometry. This pigment is reported herein for the first time.     

Image Analysis Techniques for Automated Hazelnut Peeling Determination

According to FAO statistics, in 2000, Italy was the second largest hazelnut (Corylus avellana, L. 1753) producer in the world. The price of the stock depends on the nut quality (kernel/nut ratio, nut and seed defect, percentage of peeling, and taste panel scores). The evaluation of peeling efficiency after toasting is generally conducted by trained operators in sight on 100 kernels. This work tests two alternative objective methods of after toasting peeling evaluation based on image analysis. Eleven hazelnut cultivars were analyzed and results were compared with the ones assessed by trained operators. Images were analyzed with two statistical approaches: fixed values of RGB thresholding and trained K Nearest Neighbors (KNN). Root mean squared error (RMSE), estimating the comparison between operators and the two image analysis-based techniques, shows better results for KNN (6.6) with respect to fixed threshold (15.9).     

External Shape Differences between Sympatric Populations of Commercial Clams <Emphasis Type="Italic">Tapes decussatus</Emphasis> and <Emphasis Type="Italic">T. philippinarum</Emphasis>

The actual Italian production of clams is chiefly sustained by the native Tapes decussatus and the fortuitously imported Tapes philippinarum. Both species are commercialized as “Vongola verace”, but the commercial value of T. philippinarum is lower. The discrimination of species by sight is usually difficult and it cannot be done by observation based on shell morphology but only when animals open their valves hence displaying the two siphons. In this study, we propose a new, noninvasive method to discriminate individuals of both species based on the analysis of the external shape of their shells. Accordingly, in sympatric populations at two sites of the Po river outlet, we have chosen individuals (63 for T. decussatus and 57 for T. philippinarum) of comparable commercial size for which a certain genetic discrimination was previously done. Pictures of the left side valve were taken for all specimens. Their profiles were analyzed with the elliptic Fourier analysis. The mean outline for each species was graphically extracted. The coefficients of the harmonic equations were analyzed by multivariate classification (partial least squares discriminant analysis [PLSDA]). Results showed a high percentage of correct classification of individuals of both species (96.6%). Contour analysis reflected the overall shell shape and thus identified morphological aspects that were difficult to recognize and quantify in sight. The high percentage of correct classifications obtained by combining the analysis of elliptic Fourier harmonics with PLSDA demonstrated the feasibility of this method to discriminate species with a high level of resemblance.     

Proteolytic and lipolytic changes during the ripening of León raw cow's milk cheese, a Spanish traditional variety

Proteolytic and lipolytic changes were studied throughout ripening of five batches of León cow's milk cheese, a traditional variety made in the north of Spain. Total soluble nitrogen, non-protein nitrogen, oligopeptides nitrogen, amino nitrogen and ammonia nitrogen fractions increased slightly during the ripening process. The final values of these nitrogen fractions indicate that this cheese undergoes a very slight proteolysis as much in extent as in depth. This weak protein degradation is corroborated when the caseins and their degradation products were quantified by electrophoresis. β-Casein stayed practically intact throughout the ripening process and only 10% of α_s-casein became degraded. The content of total free amino acids increased progressively but in a slightly increased way during ripening, reaching final average values of 592 mg (100 g)⁻¹ of total solids. The most abundant free amino acid at the end of ripening was lysine, followed by leucine, glutamic acid, tryptophan, valine and phenylalanine. The acidity index of the fat values increased during ripening by a factor of 4.39. The final values of this parameter are in the range of those observed in other cow's milk cheeses ripened by bacteria. The content in total free fatty acids underwent an increase throughout ripening reaching final average values of 6669 ppm. The most abundant free fatty acid at the end of ripening was oleic acid followed by butyric and palmitic acids. The high content of short-chain fatty acids is outstanding, specially that of butyric acid.