18 resultados para Microbial shelf life

em Deakin Research Online - Australia


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Sixty percent of milk consumed in China has a long shelf life (UHT), presumably because milk with a short shelf life (pasteurized) is comparatively expensive. This in contrast to Australia, where 10% of consumed milk is UHT and the price between UHT and pasteurized milk is equivalent. Whether UHT is actually more liked than pasteurized milk by Chinese consumers is unknown. However, the potential positive halo around the expensive pasteurized milk might result in Chinese consumers liking milk more when it is labeled as "short shelf-life milk." To test these hypotheses, Chinese (n=48, 20 males, 28 females, 23±7.2 yr) and Australian (n=93, 11 males, 82 females, 24±5.6 yr) consumers tasted and rated (9-point hedonic scale), in a randomized order, 3×30-mL samples of UHT milk (labeled as "long shelf-life milk," "short shelf-life milk," or "milk") and 3×30-mL samples of pasteurized milk (also labeled as "long shelf-life milk," "short shelf-life milk," or "milk"). Australian participants' liking of milk was not influenced by labeling. Regardless of what the label stated, they always preferred the taste of pasteurized milk over the taste of UHT milk. This was different for Chinese participants, who preferred the taste of UHT milk over the taste of pasteurized milk, but in general had a higher liking for any milk that was labeled "short shelf-life milk." Both Australian and Chinese were more positive about pasteurized than UHT milk. In conclusion, Chinese, but not Australian, consumers' liking of milk was guided by the positive expectations of pasteurized milk and the negative expectations of UHT milk. Further research is needed to investigate if the present findings can be extrapolated to a larger and more varied group of Chinese and Australian consumers.

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The present study was carried out in the agro-metrological conditions of Rawalpindi, Pakistan. Different potting media were used in different combinations to check their effect on the morphological parameters as well as on the vase life of the tuberose. The different treatments included the combinations of FYM, poultry manure, sand, leaf compost and coconut coir in equivalent ratio. The data was analyzed statistically which showed significant effect of media combinations over control values. Maximum plant spread, number of leaves and vase life was recorded in sand+FYM. Coconut coir + FYM contributed to the maximum values of plant height, leaf area and spike length. Maximum plantlets were counted for sand+poultry manure. The highest values of floral diameter, number of flowers per spike and shelf life were observed in sand+leaf compost. These findings lead toward better quality cut flower production with maximum vase life.

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Novel polymer-in-ionic liquid electrolytes (PILEs) have been developed for solid state electrochemical actuators based on polypyrrole. The active polymer electrodes are readily oxidized/reduced without degradation in the PILE. It was found that the actuator cycle life is significantly enhanced in the PILE as is the ‘shelf life’ of the device.

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Highly unsaturated fatty acids derived from fish or algal oils, particularly EPA and DHA, are in high demand as healthy food ingredients in fortified foods. Due to their oxidative instability most food products incorporate stabilized microencapsulated EPA and DHA oils to avoid negative sensory impact associated with oxidation of these fatty acids. Complex coacervation has been particularly successful in stabilizing fish oil and providing an ingredient with a sensory shelf-life consistent with that of the food product. Overcoming the technical challenges associated with the instability of these oils will help drive growth of the omega-3 fortified healthy food ingredient market.

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This study determines the inhibitory effect of Stevia rebaudiana leaf extracts and its purified bioactive compound ‘stevioside’ against food-related pathogens. The S. rebaudiana solvent extracts (1000 μg/mL) displayed antibacterial activity to Serratia marcescens, Klebsiella pneumoniae, Bacillus cereus, Pseudomonas aeruginosa, B. subtilis, Alcaligenes denitrificans and Salmonella typhimurium. Of the six solvents, ethanol and acetone extracts displayed the highest zone of inhibition. The bioactive compound from S. rebaudiana was purified by solvent extraction, thin-layer chromatography followed by structural characterization by spectroscopy evidence. Purified stevioside prevented the growth of tested bacterial species, i.e. B. subtilis, K. pneumoniae and S. typhimurium. Significant zone of inhibition (12 mm) was observed against B. cereus which proposes potential application of stevioside in foods to increase their shelf life.

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In this paper, we describe the surface modification of porous polyethylene by the adsorption of polyelectrolyte mutilayers on plasma‐activated polyethylene surfaces. We use the migration rates of deionized water as an effective alternative to contact angle measurements in order to probe the interfacial energy of the modified surface. The newly acquired surface properties that result from the surface modification are monitored with respect to several key chemical and environmental variables. These variables were chosen so that they will reflect some of the common handling procedures in a laboratory or health care environments, such as exposure to solvents of different pH and polarities, and fluctuations of ambient temperature over an extended period, i.e., “shelflife” duration. The stability of these surface properties of the modified membranes is a fundamental requirement for their potential use in a variety of applications involving lateral flow and binding media for bio‐assays. In this paper, we show that a membrane modified by a polyelectrolyte monolayer is more stable than a membrane that has undergone plasma activation alone, while a membrane modified by a polyelectrolyte bilayer exhibits retention of the enhanced surface hydrophilic properties under various conditions and over a long period of time.

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This thesis describes a novel approach towards the trace level detection of nitramine explosives, by exploring various reduction strategies and utilising ruthenium chemiluminescence. Synthesis of novel chemiluminescence compounds has been achieved, as well as the development of a detection method for determining the shelf life of ammunition.

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Short single-stranded oligonucleotides called aptamers, often termed as chemical antibodies, have been developed as powerful alternatives to traditional antibodies with respect to their obvious advantages like high specificity and affinity, longer shelf-life, easier manufacturing protocol, freedom to introduce chemical modifications for further improvement, etc. Reiterative selection process of aptamers over 10-15 cycles starting from a large initial pool of random nucleotide sequences renders them with high binding affinity, thereby making them extremely specific for their targets. Aptamer-based detection systems are well investigated and likely to displace primitive detection systems. Aptamer chimeras (combination of aptamers with another aptamer or biomacromolecule or chemical moiety) have the potential activity of both the parent molecules, and thus hold the capability to perform diverse functions at the same time. Owing to their extremely high specificity and lack of immunogenicity or pathogenicity, a number of other aptamers have recently entered clinical trials and have garnered favorable attention from pharmaceutical companies. Promising results from the clinical trials provide new hope to change the conventional style of therapy. Aptamers have attained high therapeutic relevance in a short time as compared to synthetic drugs and/or other modes of therapy. This review follows the various trends in aptamer technology including production, selection, modifications and success in clinical fields. It focusses largely on the various applications of aptamers which mainly depend upon their selection procedures. The review also sheds light on various modifications and chimerizations that have been implemented in order to improve the stability and functioning of the aptamers, including introduction of locked nucleic acids (LNAs). The application of various aptamers in detection systems has been discussed elaborately in order to stress on their role as efficient diagnostic agents. The key aspect of this review is focused on success of aptamers on the basis of their performance in clinical trials for various diseases.

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Red blood cells (RBCs) and platelets are examples of perishable items with a fixed shelf life. Recent studies show that transfusing fresh RBCs may lead to an improvement of patient outcomes. In addition, to better manage their inventory, hospitals prefer to receive fresh RBCs and platelets. Therefore, as well as minimizing outdates and shortages, reducing the average age of issue is a key performance criterion for blood banks. The issuing policy in a perishable inventory system has a substantial impact on the age of issue and outdate and shortage rates. Although several studies have compared the last in first out (LIFO) and the first in first out (FIFO) policies for perishable products, only a few studies have considered the situation of blood banks where replenishment is not controllable. In this study, we examine various issuing policies for a perishable inventory system with uncontrollable replenishment, and outline a modified FIFO policy. Our proposed modified FIFO policy partitions the inventory into two parts such that the first part holds the items with age less than a threshold. It then applies the FIFO policy in each part and the LIFO policy between the parts. We present two approximation techniques to estimate the average age of issue, the average time between successive outdates and the average time between successive shortages of the modified FIFO policy. Our analysis shows in several cases that where the objective function is a single economic function, or it is formulated as a multiobjective model, the modified FIFO policy outperforms the FIFO and LIFO policies.

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The use of hydrocolloids in different foods systems has become more commonly applied to improve the texture and quality of baked products. Nevertheless, the effects of these compounds on partially baked frozen chapatti have not been studied. The objective of the present study was to improve the storage stability, quality and shelf life of partially baked chapatti by adding various hydrocolloids, hydroxyl propyl methylcellulose (HPMC), carboxy methylcellulose (CMC) and guar gum, followed by frozen storage for 28 days. Partially baked and fully baked chapattis after frozen storage were analyzed for chemical and sensory attributes at 7-day intervals. Rheological studies showed an increase in water absorption, dough development time and dough stability after the addition of hydrocolloids. In partially baked chapatti with hydrocolloids after frozen storage, an increase in moisture retention and water soluble starch was observed. Sensory characteristics were also improved by combining both techniques. Among the hydrocolloids, HPMC exhibited the best results, followed by CMC and guar gum. These hydrocolloids and partial baking with frozen storage helped to improve the quality, and extend the shelf life of partially baked chapatti.

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Background: In the context of rising food prices, there is a need for evidence on the most effective approaches for promoting healthy eating. Individually-targeted behavioural interventions for increasing food-related skills show promise, but are unlikely to be effective in the absence of structural supports. Fiscal policies have been advocated as a means of promoting healthy eating and reducing obesity and nutrition-related disease, but there is little empirical evidence of their effectiveness. This paper describes the Supermarket Healthy Eating for LiFe (SHELf) study, a randomised controlled trial to investigate effectiveness and cost-effectiveness of a tailored skill-building intervention and a price reduction intervention, separately and in combination, against a control condition for promoting purchase and consumption of healthy foods and beverages in women from high and low socioeconomic groups.
Methods/design: SHELf comprises a randomised controlled trial design, with participants randomised to receive either (1) a skill-building intervention; (2) price reductions on fruits, vegetables and low-joule soft drink beverages and water; (3) a combination of skill-building and price reductions; or (4) a control condition. Five hundred women from high and low socioeconomic areas will be recruited through a store loyalty card program and local media. Randomisation will occur on receipt of informed consent and baseline questionnaire. An economic evaluation from a societal perspective using a cost-consequences approach will compare the costs and outcomes between intervention and control groups.
Discussion: This study will build on a pivotal partnership with a major national supermarket chain and the Heart Foundation to investigate the effectiveness of intervention strategies aimed at increasing women’s purchasing and consumption of fruits and vegetables and decreased purchasing and consumption of sugar-sweetened beverages. It will be among the first internationally to examine the effects of two promising approaches - skill-building and price reductions - on diet amongst women.

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BACKGROUND: Supermarket Healthy Eating for Life (SHELf) was a randomized controlled trial that operationalized a socioecological approach to population-level dietary behaviour change in a real-world supermarket setting. SHELf tested the impact of individual (skill-building), environmental (20 % price reductions), and combined (skill-building + 20 % price reductions) interventions on women's purchasing and consumption of fruits, vegetables, low-calorie carbonated beverages and water. This process evaluation investigated the reach, effectiveness, implementation, and maintenance of the SHELf interventions.

METHODS: RE-AIM provided a conceptual framework to examine the processes underlying the impact of the interventions using data from participant surveys and objective sales data collected at baseline, post-intervention (3 months) and 6-months post-intervention. Fisher's exact, χ (2) and t-tests assessed differences in quantitative survey responses among groups. Adjusted linear regression examined the impact of self-reported intervention dose on food purchasing and consumption outcomes. Thematic analysis identified key themes within qualitative survey responses.

RESULTS: Reach of the SHELf interventions to disadvantaged groups, and beyond study participants themselves, was moderate. Just over one-third of intervention participants indicated that the interventions were effective in changing the way they bought, cooked or consumed food (p < 0.001 compared to control), with no differences among intervention groups. Improvements in purchasing and consumption outcomes were greatest among those who received a higher intervention dose. Most notably, participants who said they accessed price reductions on fruits and vegetables purchased (519 g/week) and consumed (0.5 servings/day) more vegetables. The majority of participants said they accessed (82 %) and appreciated discounts on fruits and vegetables, while there was limited use (40 %) and appreciation of discounts on low-calorie carbonated beverages and water. Overall reported satisfaction with, use, and impact of the skill-building resources was moderate. Maintenance of newly acquired behaviours was limited, with less than half of participants making changes or using study-provided resources during the 6-month post-intervention period.

CONCLUSIONS: SHELf's reach and perceived effectiveness were moderate. The interventions were more effective among those reporting greater engagement with them (an implementation-related construct). Maintenance of newly acquired behaviours proved challenging.

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Mixed-species restoration tree plantings are being established increasingly, contributing to mitigate climate change and restore ecosystems. Including nitrogen (N)-fixing tree species may increase carbon (C) sequestration in mixed-species plantings, as these species may substantially increase soil C beneath them. We need to better understand the role of N-fixers in mixed-species plantings to potentially maximize soil C sequestration in these systems. Here, we present a field-based study that asked two specific questions related to the inclusion of N-fixing trees in a mixed-species planting: 1) Do non-N-fixing trees have access to N derived from fixation of atmospheric N2 by neighbouring N-fixing trees? 2) Do soil microbial communities differ under N-fixing trees and non-N-fixing trees in a mixed-species restoration planting? We sampled leaves from the crowns, and litter and soils beneath the crowns of two N-fixing and two non-N-fixing tree species that dominated the planting. Using the 15N natural abundance method, we found indications that fixed atmospheric N was utilized by the non-N-fixing trees, most likely through tight root connections or organic forms of N from the litter layer, rather than through the decomposition of N-fixers litter. While the two N-fixing tree species that were studied appeared to fix atmospheric N, they were substantially different in terms of C and N addition to the soil, as well as microbial community composition beneath them. This shows that the effect of N-fixing tree species on soil carbon sequestration is species-specific, cannot be generalized and requires planting trails to determine if there will be benefits to carbon sequestration. © 2014 Elsevier Ltd.

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Catalase, an oxidoreductase enzyme, works as a detoxification system inside living cells against reactive oxygen species formed as a by-product of different metabolic reactions. The enzyme is found in a wide range of aerobic and anaerobic organisms. Catalase has also been employed in various analytical and diagnostic methods in the form of biosensors and biomarkers in addition to its other applications in textile, paper, food and pharmaceutical industries. New applications for catalases are constantly emerging thanks to their high turnover rate, distinct evolutionary origin, relatively simple and well-defined reaction mechanisms. The following review provides comprehensive information on isolation, production and purification of catalases with different techniques from various microbial sources along with their types, structure, mechanism of action and applications.