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1.
The impact of cooling temperatures on gel characteristics of set-type yoghurts was investigated through 28 days of storage. Yoghurt samples were cooled at four different temperatures (−10 °C, −5 °C, 0 °C, 4 °C) after incubation until the central temperature of yoghurt cups reached 4 °C. Cooling temperature and storage period were determined as significant factors affecting the yoghurt gel characteristics (p < 0.05). Yoghurts cooled at 0 °C clearly differed from the other yoghurts in terms of gel firmness and consistency. Confocal images of yoghurts cooled at 0 °C showed more homogeneous protein matrix than the other samples. Microbial counts and the acidity of the yoghurt samples increased with storage period. Textural parameters, water holding capacity and susceptibility to syneresis increased until 14th day of storage and then decreased. Sensory analysis of yoghurt samples confirmed the results obtained by microbiological and textural measurements.  相似文献   

2.
The distribution of biotic and abiotic factors creates ecological niches. Despite the link between both the biotic and abiotic components of a species niche and its geographic distribution, most approaches to species-distribution modeling correlate the occurrence of a single species with broad-scale environmental variables, but do not include biotic interactions. We studied the relative effects of biotic and abiotic factors on community composition and dynamics in a man-made ecosystem (i.e., a grain-storage system). We studied the population dynamics of 10 insect species at two climatically distinct study sites: a site with a Mediterranean climate and a site with a semi-arid climate. All species were found to aggregate at both sites and similar community dynamics were observed at the two sites. However, there were differences in the relative importance of biotic and abiotic factors in the formation of communities in the two habitats. This difference yielded different population dynamics and spatial distributions. The Mediterranean site was characterized by species niche overlap and communities at that site were less dense. In contrast, in the semi-arid habitat, species tended to have distinct spatial distribution and there was a high level of community density. These results can be viewed as examples of within- and between-patch coexistence. We discuss the possibility that there may be gradual shifts in the relative importance of within- and between-patch coexistence. Small continuous changes, such as global climate change, could induce such shifts, leading to similar temporal and spatial patterns in the current Mediterranean climate.  相似文献   

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Not only feed but also respective bolus particle size could alter diet efficiency and cow performance. The objective of this project was to characterize particle size of selected feeds and respective swallowed boli. Feed samples included 6 different particle length rye grass hay samples, 1 grass silage, 1 corn silage, and 1 total mixed ration (TMR). Rye grass hay samples consisted of long hay and chopped hay particles retained on the 19- (19_PSPS hay), 8- (8_PSPS hay), and 1.18-mm (1.18_PSPS hay) Penn State Particle Separator (PSPS) screens and those collected on the pan (PSPS_pan hay). A sixth hay treatment was rye grass forage cut at 50-mm lengths and dried to hay (50-mm hay). Treatments were offered to 4 nonlactating and 4 lactating cows following rumen evacuation. Swallowed boli were collected and the number of chews per gram of ingested feed dry matter was determined. Feed and bolus particles of lengths ≥5mm were collected on a 1.6-mm screen using a horizontal wet sieving technique. This cut point was chosen, as the literature suggests that most fecal particles are shorter than 5mm. Dry matter proportions on this screen (PROP_1.6) were determined and particle lengths of retained particles were measured by image analysis. Mean particle lengths (ML) were calculated considering particles ≥5mm in length. Boli of long hay, of 19_PSPS hay, of 8_PSPS hay, and of 50-mm hay had similar ML of 10 to 11mm. Bolus PROP_1.6 were also similar between these treatments, ranging from 0.54 to 0.69. Bolus particle lengths and distributions of these treatments were not related to respective hay particles. Bolus of 1.18_PSPS hay had PROP_1.6 of 0.51 and a smaller ML of 8mm. The PSPS_pan hay had PROP_1.6 of only 0.33, but was still chewed intensely. Apparently, little particle size reduction occurred when cows ate the TMR or the silages. Feed and respective bolus PROP_1.6 were as follows: 0.66 and 0.59 in grass silage, 0.52 and 0.55 in corn silage, and 0.44 and 0.38 in the TMR. Feed and respective bolus ML were as follows: 13.8 and 11.6mm in grass silage, 12.0 and 11.2mm in corn silage, and 13.1 and 12.5mm in the TMR. Rye grass hay particles retained on PSPS screens ≥8mm, with ML of at least 25mm were longer compared with TMR particles, but respective bolus particles were shorter. Bolus particle size is not associated with the size of large feed particles chewed to a constant size that is appropriate for deglutition. This size may be related to feed chemical composition.  相似文献   

5.
Information about the mobility and the partitioning properties of brominated persistent organic pollutants, the environmental levels of which are sometimes higher than those of the chlorinated analogues, is limited. We estimated n-octanol/ water (log K(OW)), n-octanol/air (log K(OA)), and air/water (log K(AW)) partition coefficients for 1436 chloro- and bromo-analogues of dibenzo-p-dioxins, dibenzofurans, biphenyls, naphthalenes, diphenyl ethers, and benzenes by employing quantitative structure-property relationship (QSPR) techniques. The searches for similar partitioning patterns were performed by means of two-dimensional cluster analysis. Five classes of compounds were identified. Each of the class is characterized by similar partition coefficients and, in consequence, similar environmental properties. Finally the data was fitted into a simple multimedia model involving the partitioning map. In addition, we found thatthe changes in the partition coefficients upon the replacement of chlorine with bromine were constant: 0.11, 0.31, and -0.21 per bromine atom for log K(OW), log K(OA), and log K(AW), respectively. On the basis of this observation, a method for rapid estimation of changes in the partition coefficient upon chlorine-bromine substitution was proposed.  相似文献   

6.
The multiple protective functions of the skin derive from the interactions between epithelial skin and immune cells as well as the commensal microbiota. Developed in the last trimester of intra-uterine life, the skin barrier adapts dynamically after birth. Specific differences in the structure and physiology have been disclosed between infant and adult skin. The stratum corneum of infants is thinner and structured by thicker corneocytes with a more anisotropic surface in comparison to adult skin. Lower levels of the natural moisturizing factor and its constituents, together with the increased protease activity in the epidermis result in dry baby skin and ongoing adaptation of the desquamation to the extra-uterine environment. Infant epidermis is characterized by an accelerated proliferation rate and clinically competent permeability barrier in term neonates, despite the higher baseline values of transepidermal water loss in infants. The skin surface of newborns is less acidic, which could increase susceptibility to diaper and atopic dermatitis. Immediately after birth, skin is colonized by commensal bacteria—a process dependent on the mode of delivery and of major importance for the maturation of the immune system. Skin bacterial diversity and dysbiosis have been related to different pathology such as atopic and seborrheic dermatitis. This paper focuses on the ongoing structural, functional and biochemical adaptation of the human skin barrier after birth. We discuss the interactions on the ‘skin barrier/ microbiota/ immune system’ axis and their role in the development of competent functional integrity of the epidermal barrier.  相似文献   

7.
Nutritional warnings have emerged as a promising front-of-package nutrition labelling scheme to discourage consumption of products with high content of nutrients associated with non-communicable diseases. One of the objectives of this policy is to encourage the food industry to reformulate their products. However, information about consumers’ perception of reformulated products in the context of the implementation of this policy is still limited. The aim of this study was to assess the relative influence of different types of reformulation on consumers’ perceived healthfulness and purchase intention, using frankfurters as case study. A conjoint analysis was implemented considering a fractional factorial design involving 5 2-level variables: brand type (artisanal/industrial), sodium reduction (with/without), saturated fat reduction (with/without), fibre claim (with/without) and cholesterol claim (with/without). An online survey with 494 consumers was implemented one year after the implementation of nutritional warnings in Chile. Participants were randomly divided into two groups, one of which evaluated purchase intention (n = 249) and the other evaluated perceived healthfulness (n = 245). Data were analysed using analysis of variance and cluster analysis. Results showed that reformulated products without nutritional warnings for sodium and saturated fat were perceived as more healthful and had higher purchase intention scores than then regular counterparts. On the contrary, nutrient claims did not have a relevant effect on consumers’ perception. Heterogeneity in consumers’ reaction to the reformulated products was found and was mainly related to consumption frequency of the product category. Results provide insights for policy makers and food companies in countries considering the implementation of nutritional warnings.  相似文献   

8.
Consumer interest in nutritious and innovative foods encourages the development of products based on raw materials with nutraceutical potential. The health benefits provided by pomegranate have been recognized; therefore, the development of pomegranate juice may match consumer expectations regarding this goal. However, the concept has to first be accepted by the consumer. The aim of the study was to utilize a rating based conjoint analysis to investigate how Brazilian consumers perceive pomegranate juice by identifying the role of packaging attributes relevant to the consumer's intention to purchase. Five factors were considered in the study: technology used in the juice production (high hydrostatic pressure – HHP – a technology that preserves nutritional and sensory properties), antioxidants, price, preservatives, and colorant. Eight hypothetical pomegranate juice packages were created following an incomplete block design and evaluated by 150 fruit juice consumers. Three clusters were identified. The average results revealed that antioxidants were the attribute of greatest relative importance to cluster 1 (RI: 36%), followed by HHP (RI: 25%) and colorants (14%). Consumers in cluster 2 considered price as the most important attribute (RI: 41%), followed by antioxidants (RI: 21%) and HHP (RI: 18%). Cluster 3, as well as cluster 2, considered price the most important attribute (RI: 28%), followed by antioxidants (RI: 26%) and HHP (RI: 22%). The results showed that consumers valued information on the health benefits of antioxidants as well as on the technology, suggesting that both types of information may be relevant tools to increase the intention to purchase the product. The application of HHP for pomegranate juice processing was positively perceived by consumers, suggesting a potential commercial application in the Brazilian industry.  相似文献   

9.
How many check dams do we need to build on the loess plateau?   总被引:4,自引:0,他引:4  
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10.
Objectives: Half of US states have minimum cigarette price laws that were originally passed to protect small independent retailers from unfair price competition with larger retailers. These laws prohibit cigarettes from being sold below a minimum price that is set by a formula. Many of these laws allow cigarette company promotional incentives offered to retailers, such as buydowns and master-type programmes, to be calculated into the formula. Allowing this provision has the potential to lower the allowable minimum price. This study assesses whether stores in states with minimum price laws have higher cigarette prices and lower rates of retailer participation in cigarette company promotional incentive programmes.

Design: Retail cigarette prices and retailer participation in cigarette company incentive programmes in 2001 were compared in eight states with minimum price laws and seven states without them. New York State had the most stringent minimum price law at the time of the study because it excluded promotional incentive programmes in its price setting formula; cigarette prices in New York were compared to all other states included in the study.

Results: Cigarette prices were not significantly different in our sample of US states with and without cigarette minimum price laws. Cigarette prices were significantly higher in New York stores than in the 14 other states combined.

Conclusions: Most existing minimum cigarette price laws appear to have little impact on the retail price of cigarettes. This may be because they allow the use of promotional programmes, which are used by manufacturers to reduce cigarette prices. New York's strategy to disallow these types of incentive programmes may result in higher minimum cigarette prices, and should also be explored as a potential policy strategy to control cigarette company marketing practices in stores. Strict cigarette minimum price laws may have the potential to reduce cigarette consumption by decreasing demand through increased cigarette prices and reduced promotional activities at retail outlets.

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The study aimed at investigating the influence of four variables related to processing technology and formulation on consumer’s choice of fruit juice, and to explore the moderating effect of food technology neophobia (FTN). A choice-conjoint task was implemented considering four variables: processing technology, added sugar, preservatives and cold pressing. Sixteen pairs of labels were presented to 369 Brazilian consumers to that indicate which of the products they would purchase. Then, they answered the FTN scales and a socio-demographic questionnaire. Data were analysed using a logit model with random parameters. Results showed that cold pressing, pressurisation and the claims ‘no added sugar’ and ‘no preservatives’ had a positive effect on consumers’ choices, whereas the claim ‘not pressurised’ had a negative effect. The FTN moderated the effect of the variables on participants' choices of fruit juices. The main difference between groups of consumers with different level of neophobia (low, medium and high) was related to the effect of information about juice processing.  相似文献   

13.
The influences of three different culinary methods: cooking, sous vide and grilling were studied with regards to quality and oral processing characteristics of pork ham. Besides instrumental analysis of color and textural properties of pork ham, sensory panel with 12 trained panelists participated in temporal dominance of sensations, oral processing analysis, boluses collection, particle size distribution analysis, and saliva incorporation. The results revealed that number of chews, mastication time and saliva incorporation are correlated with textural properties and cooking losses. In‐mouth sensation was intertwined with juiciness, fibrousness and firmness depending on the culinary methods. Cooked pork ham showed highest results for hardness and cooking loss. Firmness and fibrousness were dominant sensory attributes. Sous‐vide results show that firmness and juiciness dominated during the first third of consumption time. This corresponds with textural values for lowest values for hardness and cooking, number of chews and total exposure time. Sous‐vide also resulted in lower values for number of chews and total exposure time associated with oral processing.  相似文献   

14.
Escherichia coli O157:H7 is but one of a group of Shiga toxin-producing E. coli (STEC) that cause both intestinal disease such as bloody and nonbloody diarrhea and serious complications like hemolytic uremic syndrome (HUS). While E. coli O157: H7 is the most renowned STEC, over 200 different types of STEC have been documented in meat and animals, at least 60 of which have been linked with human disease. A number of studies have suggested that non-O157 STEC are associated with clinical disease, and non-O157 STEC are present in the food supply. Non-O157 STEC, such as O111 have caused large outbreaks and HUS in the United States and other countries. The current policy in the United States is to examine ground beef for O157:H7 only, but restricting the focus to O157 will miss other important human STEC pathogens.  相似文献   

15.
Food allergy is a growing health problem with serious concerns due to high potential for fatality. Rapid advances in the knowledge on causes and mechanisms as well as in developing effective prevention/therapeutic strategies are needed. To meet these goals, mouse models that simulate the human disorder are highly desirable. During the past decade, several mouse models of food allergies have been reported. Here, we briefly reviewed the human disorder and then critically evaluated these models seeking answers to the following important questions: To what extent do they simulate the human disorder? What are the strengths and limitations of these models? What are the challenges facing this scientific area? Our analysis suggest that: (i) the mouse models, with inherent strengths and limitations, are available for many major food allergies; there is scope for additional model development and validation; (ii) models mostly simulate the severe forms of human disorder with similar immune and clinical features; (iii) the approaches used to develop some of the mouse models may be questionable; and (iv) the specific mechanisms of sensitization as wells as oral elicitation of fatal reactions in both humans and mice remains incompletely understood and therefore warrants further research.  相似文献   

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Peripheral milling with up-milling and down-milling techniques is very well known from a geometrical point of view. However, in processing anisotropic materials such as wood these geometrical aspects imply relevant differences when machining. In fact milling anisotropic materials leads to different cutting geometries when up-milling or down-milling and when changing the depth of cut. This results in a relative orientation of the grain depending on the process adopted. In this paper the geometrical interactions between tool and wood grain have been analysed theoretically and supported by experimental evidence. To achieve this result, Douglas fir has been processed with different depths of cut and grain orientations, the resulting chips have been collected and analysed. The experiments show how a shift of the cutting phenomenon and the chip type can be observed to support the theoretical background.  相似文献   

18.
Consumers around the globe are showing an increasing demand for food products that are perceived as being natural. The present study aimed to assess what properties of wine have an influence on the perceived naturalness of wine, with a focus on winemaking techniques. An online survey was conducted in the German-speaking part of Switzerland (n = 252) and in Australia (n = 234). Wine naturalness was significantly more important to Swiss respondents compared to Australian respondents as well as to respondents with a high level of involvement with wine compared to respondents with a low level of involvement. Wine from an “Old World” wine-producing country, wine that was aged in barriques, or wine sealed with an oak cork were perceived as the most natural. The addition of sugar, sulfites, or the use of gelatin were regarded as the most unnatural properties of wine. In terms of production, additives were perceived as significantly less natural than processing aids and technologies that are used in winemaking. Significant differences in the naturalness perception of different wine attributes were found between the two countries, Switzerland and Australia, as well as between respondents with a high level of involvement with wine and those with a low level. The findings of this study add to the research on naturalness perception and may help winemakers and marketers to optimize communication with their consumers.  相似文献   

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The major driving force for the egg consumption in the United States over the past few decades was processed egg. However, the consumption of egg through the processed egg reached the plateau in recent years because of the imbalance in the demands between the egg white and yolk products. The consumer demands for egg white products are very high while those for the egg yolk, the co‐product of dried egg white, are low because of the negative perceptions on egg yolk. Two key approaches that can be used to increase the value and use of egg yolk are: (1) developing new commodity products by fractionating egg yolk and apply them in various food processing, and (2) separating functional proteins and lipids from yolk and use them as is or further develop functional peptides and functional lipids and use them as pharmaceutical, nutraceutical, and cosmeceutical agents. These approaches can diversify the use of egg yolk, which eventually will help increase the consumption of egg. This review (1) discusses the current use of egg yolk products and the development of new functional commodity products from egg yolk, (2) review the important functional components in egg yolk and overview the current separation methods and their applications, (3) discuss the production of functional peptides and lipids using the separated egg proteins and lipids, and (4) suggest the future directions for the best use of egg yolk components. Development of scale‐up production methods, which is vital for the practical applications, is discussed when appropriate.  相似文献   

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