Fatty acid composition and CLA content in goat milk and cheese samples from Umbrian market

Goat dairy products are considered as a suitable alternative to cow milk products for some special categories of consumers (infants, old, and convalescent people). In the present research, a study on the lipid fraction of commercial goat milk and cheese samples purchased from Umbrian market was carried out. Particular attention has been paid to evaluating conjugated linoleic acid (CLA) content and determining some interesting nutritional indexes. The results of goat milk samples showed that saturated, monounsaturated and polyunsaturated fatty acid contents were on average 71.2, 23.4, and 3.8 %, respectively. CLA content (cis-9, trans-11 isomer) was on average 11.5 mg/100 g in milk. Considerable variability was observed for n6/n3 ratio that varied from 2.7 to 10.6 in the considered goat milk samples. With regard to goat cheese samples CLA concentration was on average 118.8 mg/100 g in fresh cheese and 217.7 mg/100 g in semi-hard cheese, and the difference was not significant. Interestingly, α-linolenic acid content was higher and n6/n3 ratio was lower in semi-hard with respect to fresh cheese samples (p < 0.05).     

Volatile compounds and descriptive odor attributes in umbu (Spondias tuberosa) fruits during maturation

The umbu fruit is appreciated in north and northeast region of Brazil mainly because of its refreshing and acidic flavor. The objective of this work was to determine the volatile compounds in half-ripe and ripe stages of umbu fruit and to identify important characteristic compounds which could contribute for its aroma by performing sniffing evaluation of volatile extracts. The principal volatile compounds identified in the ripe umbu fruit pulp were 4-methyl-3-penten-2-one, ethyl benzene, 1-penten-3-one, 2-acetyl thiazone, p-xylene, limonene, 2,2-dimethyl 4-octenal, 3-hexanol, 2-nonanol, 1-nonanol, 2-pentanol, 2-octanol, 3-methylethyl 2-butanoate, butyl benzoate, 3-allyl cyclohexene, 2-acetyl furan, 2-hexyl furan, ??-caryophyllene and methyl pyrazine. A total of 37 volatile compounds were diagnosed with characteristic aroma attributes. The principal volatile compounds which could be responsible for the characteristic aroma of ripe umbu fruit pulp were ??-(Z)-ocimene, methyl pyrazine, 2-butyl-thiophene, methyl octanoate, 2-hexyl furan, 2-octanol, (E)-2-cyclohexen-1-one, 3-bromo-cyclohexene, 1-heptanol, 2-nonanol and 1-octanol.     

Acrylamide formation and colour development in low-fat baked potato products as influenced by baking conditions and oil type

The objective of this study was to investigate the effect of oil type and oxidation status on acrylamide (AA) formation and colour development in potato products under domestic baking conditions. Sunflower, soybean and olive oil were used; the first one was thermally oxidized to obtain different oxidation status. A potato dough containing 10 % oil, potato powder, flour and water was shaped into thin discs and baked at 180 °C for different heating times. AA concentration, moisture content and surface colour were determined. Results obtained showed that neither the nature of lipids present, in terms of content of unsaturated fatty acids, nor the degree of fat oxidation influenced AA formation in low-fat baked potato products. Browning ratio higher than 45 % and moisture content lower than 17 % resulted in dark brown, almost burnt, products. Moreover, in those cases, no correlation could be found between those variables and AA content, since formation and degradation simultaneously occur. When the browning ratio ranged between 0 and 45 %, a good linear correlation with AA formation was observed, suggesting that the browning ratio may be considered as a reliable indicator of AA concentration. Finally, AA less than 1000 μg/kg, which is an indicative value that has been recently set for potato crisps by the European Commission, corresponds to a browning ratio of less than 8 % and moisture content more than 23.5 %.     

34—A CONTRIBUTION TO THE STUDY OF THE INFLUENCE OF THE DESIGN OF THE YARN-WITHDRAWAL TUBE ON THE DIAMETER AND HAIRINESS OF OPEN-END-SPUN ACRYLIC-FIBRE YARNS

An investigation is reported in which factorial experiments were conducted to study the influence of the design of the yarn-withdrawal tube (or nozzle) on the diameter and hairiness of open-end-spun acrylic-fibre yarns. Three nozzle types, combined with three values of yarn linear density and five values of twist multiplier, were studied for four different (but equal-diameter) rotor types. lt is shown that the nozzle type has very little influence on yarn diameter but has a more significant effect on yarn-hairiness parameters. As the nozzle diameter increases, yarn hairiness also tends to increase, but, when the nozzle is grooved, an interaction is produced between yarn friction and the false twist generated that leads to a yarn that is less hairy when tested on the Digital ITQT Hairiness Meter. The principle of measurement of the apparatus used can lead to different results and trends when applied to this problem.     

富有魔力的等离子体技术

》》等离子体技术是当今高新技术发展的前沿技术之一.通过等离子体表面改性能改善纤维的多种性能,提高利用价值,并且省能节水,有利于环境保护.尽管目前等离子体技术还不完善,在纺织领域的应用尚未得到推广,但其开发前景令人期待.     

如果环境重要(下)纺织行业寻求终极生态纤维——有机、再生、可循环

翠绿色--挖掘合成纤维的可循环潜质 尽管合成纤维不是来源于可再生的生物基原材料,但它也可能是一种对环境友好的选择.仅仅凭借生物来源的优势是不够的,随着越来越多的可再生和可循环合成材料的发展,源自石油的材料在生态方面也开始崭露头脚.合成纤维的优势有两方面,即价格优惠的可靠来源和功能性.     

A comparative study of composition and postharvest performance of organically and conventionally grown kiwifruits

Postharvest performance of organic and conventional ‘Hayward’ kiwifruits grown on the same farm in Marysville, California, and harvested at the same maturity stage were compared in this study. Quality parameters monitored included morphological (shape index) and physical (peel characteristics) attributes of the initial samples. Maturity indices (CO₂ and C₂H₄ production, firmness, color, soluble solids content and acidity) and content of compounds associated with flavor and nutritional quality (minerals, sugars and organic acids, ascorbic acid, total phenolics, and antioxidant activity) were determined at 0, 35, 72, 90 and 120 days of storage at 0°C, and after 1 week of shelf‐life simulation at 20°C, after each storage duration. Organically and conventionally grown kiwifruits had similar soluble solids content at harvest, but conventional kiwifruits had a higher firmness and L* value, and a lower hue angle and chromaticity, resulting in a lighter green color when compared with the organic kiwifruits. These differences were maintained for all the storage durations, with the soluble solids content increasing more in conventionally grown kiwifruits. The two production systems resulted in different morphological attributes since organic kiwifruits exhibited a larger total and columella area, smaller flesh area, more spherical shape, and thicker skin compared to conventional kiwifruits. All the main mineral constituents were more concentrated in organic kiwifruits, which also had higher levels of ascorbic acid and total phenol content, resulting in a higher antioxidant activity. Sugars and organic acids composition was not affected by the production system. Copyright © 2007 Society of Chemical Industry     

Development and comparison of loop-mediated isothermal amplification and quantitative polymerase chain reaction assays for the detection of Mycoplasma bovis in milk

Bovine mastitis is an economic burden for dairies worldwide. Mycoplasma species, and especially Mycoplasma bovis, are among the most important causative agents, and rapid, precise, and low-cost methods for Mycoplasma detection are urgently needed. For this purpose, loop-mediated isothermal amplification (LAMP) and quantitative PCR (qPCR) assays were developed and compared. The LAMP assay was designed and primer concentrations optimized to M. bovis oppD, encoding oligopeptide permease D. For qPCR, a Taqman assay (Applied Biosystems, Carlsbad, CA) targeting M. bovis gltX, encoding glutamate transfer RNA ligase, was optimized for primer concentration, annealing temperature, and DNA polymerase. Both assays were similarly sensitive, with a detection limit of approximately 10⁴ to 10⁵ M. bovis cells/mL. Both assays were also successful in confirming M. bovis identity in laboratory culture suspensions and in bovine milk. The LAMP and qPCR assays combined with the MoBio DNA extraction kit (MoBio Laboratories Inc., Carlsbad, CA) resulted in the correct detection of 13 out of 13 M. bovis isolates and 14 out of 16 M. bovis-positive milk samples collected from commercial dairies in California. When combined with the PrepMan Ultra reagent (Applied Biosystems), the qPCR assay resulted in confirming 21 out of 21 M. bovis-positive milk samples. Comparison of the assays to milk containing either Mycoplasma arginini, Mycoplasma bovigenitalium, Mycoplasma californicum, M. alkalescens, or Acholeplasma laidlawii or milk lacking any detectable Mycoplasma species or relatives resulted in 3 out of 17 (LAMP with MoBio), 1 out of 17 (qPCR with MoBio), and 2 out of 36 (qPCR with PrepMan Ultra) false positives. Overall, the qPCR assay was more robust than LAMP and could be used on DNA recovered from milk prepared with the PrepMan Ultra reagent, a method that does not include a DNA purification step. The use of this qPCR method enables M. bovis detection in bovine milk in 40 to 55 min, and therefore provides new opportunities to accelerate and simplify M. bovis detection in unpasteurized milk to reduce the incidence of M. bovis mastitis outbreaks.     

Microstructure of industrially manufactured goat cheese Queso de Murcia al Vino during synaeresis

The microstructural parameters of an industrially manufactured goat cheese curd (pore number, area and perimeter, strand thickness and porosity) were analysed by scanning electron microscopy and image analysis during synaeresis. The water‐holding capacity, whey fat, pH and moisture content were also determined to establish any relationship with the curd microstructure. The quantification of the different microstructural parameters made it possible to assign pitching and stirring as important processing steps because these steps impart different features to the curd microstructure. Higher pore number was related to reduced pore area, perimeter and strand thickness, but higher porosity and moisture.