MIKROENKAPSULASI d-LIMONEN UNTUK PERISAAN PRODUK EKSTRUSI

ABSTRACTThe objectives of this research are to determine the effect of microencapsulation on d-limonene retention in starch extrudates and the effect of incorporating encapsulated d-limonene on extruder operation and extrudate properties. Two set of extrusion experiments were carried out in a twin screw extruder (16 mm diameter screw; 40:1 L/D ratio) using corn starch as a food matrix. In one set of experiments, d-limonene was encapsulated in -cyclodextrin. In the other experiments, d-limonene was encapsulated with sodium caseinate. Using a Central Composite Design, three variables were studied: level of encapsulated d-limonene in the feed material, extruder screw speeds and barrel temperatures. Another set of experiment with unencapsulated d-limonene was also performed. Measured parameters included extruder operation parameters (torque and die melt pressure), extrudate properties (expansion ratio and hardness) and d-limonene retention.  All variables contributed significantly to the d-limonene retention and extrudate properties. -Cyclodextrin capsules gave higher d-limonene retention (average of 92.2%) than the sodium caseinate capsules (67.5%). A higher expansion ratio was observed from the extrudates containing sodium caseinate capsules than those with -cyclodextrin (average of 1.87 and 1.38, respectively). Extrudates containing -cyclodextrin capsules had a lower hardness (average of 1.14 N/mm2) than those with sodium caseinate capsules (average 2.34 N/mm2). Without encapsulation, retention of d-limonene was the lowest (average of 8.0%), extrudate hardness was the highest (average of 3.38 N/mm2) but expansion ratio was the highest (average of 2.1).    Keywords    :     flavour, microencapsulation, extrusion, d-limonene, -cyclodextrin, sodium caseinate, expansion, textur

MIKROENKAPSULASI d-LIMONEN UNTUK PERISAAN PRODUK EKSTRUSI

ABSTRACTThe objectives of this research are to determine the effect of microencapsulation on d-limonene retention in starch extrudates and the effect of incorporating encapsulated d-limonene on extruder operation and extrudate properties. Two set of extrusion experiments were carried out in a twin screw extruder (16 mm diameter screw; 40:1 L/D ratio) using corn starch as a food matrix. In one set of experiments, d-limonene was encapsulated in -cyclodextrin. In the other experiments, d-limonene was encapsulated with sodium caseinate. Using a Central Composite Design, three variables were studied: level of encapsulated d-limonene in the feed material, extruder screw speeds and barrel temperatures. Another set of experiment with unencapsulated d-limonene was also performed. Measured parameters included extruder operation parameters (torque and die melt pressure), extrudate properties (expansion ratio and hardness) and d-limonene retention.  All variables contributed significantly to the d-limonene retention and extrudate properties. -Cyclodextrin capsules gave higher d-limonene retention (average of 92.2%) than the sodium caseinate capsules (67.5%). A higher expansion ratio was observed from the extrudates containing sodium caseinate capsules than those with -cyclodextrin (average of 1.87 and 1.38, respectively). Extrudates containing -cyclodextrin capsules had a lower hardness (average of 1.14 N/mm2) than those with sodium caseinate capsules (average 2.34 N/mm2). Without encapsulation, retention of d-limonene was the lowest (average of 8.0%), extrudate hardness was the highest (average of 3.38 N/mm2) but expansion ratio was the highest (average of 2.1).    Keywords    :     flavour, microencapsulation, extrusion, d-limonene, -cyclodextrin, sodium caseinate, expansion, textur

Soaking grapevine cuttings in water: a potential source of cross contamination by micro-organisms

Grapevine nurseries soak cuttings in water during propagation to compensate for dehydration and promote root initiation. However, trunk disease pathogens have been isolated from soaking water, indicating cross contamination. Cuttings of Vitis vinifera cv. Sunmuscat and V. berlandieri x V. rupestris rootstock cv. 140 Ruggeri were immersed in sterilized, deionised water for 1, 2, 4, 8 and 16 h. The soaking water was cultured (25°C for 3 days) on non-specific and specific media for fungi and bacteria. The base of each cutting was debarked and trimmed and three 3 mm thick, contiguous, transverse slices of wood cultured at 25°C for 3 days. The soaking water for both cultivars became contaminated with microorganisms within the first hour. Numbers of fungi iso-lated from the wood slices soaked for one hour were significantly greater than those from non-soaked cuttings. The number of bacterial colonies growing from the wood slices increased after soaking for 2‒4 h in Sunmuscat. In a second experiment Shiraz cuttings were soaked for 1, 2, 4, 8 and 24 h. The soaking water became contaminated within the first hour but only the bacterial count increased significantly over time. Microorganisms also established on the container surfaces within the first hour although there were no significant increases over 24 h. These results confirm that soaking cuttings is a potential cause of cross contamination and demonstrate contamination of cuttings occurs after relatively short periods of soaking. Avoiding exposing cuttings to water will reduce the transmission of trunk diseases in propagation

Expression of miRNAs in ovine fetal gonads: potential role in gonadal differentiation

<p>Abstract</p> <p>Background</p> <p>Gonadal differentiation in the mammalian fetus involves a complex dose-dependent genetic network. Initiation and progression of fetal ovarian and testicular pathways are accompanied by dynamic expression patterns of thousands of genes. We postulate these expression patterns are regulated by small non-coding RNAs called microRNAs (miRNAs). The aim of this study was to identify the expression of miRNAs in mammalian fetal gonads using sheep as a model.</p> <p>Methods</p> <p>We determined the expression of 128 miRNAs by real time PCR in early-gestational (gestational day (GD) 42) and mid-gestational (GD75) sheep ovaries and testes. Expression data were further examined and validated by bioinformatic analysis.</p> <p>Results</p> <p>Expression analysis revealed significant differences between ovaries and testes among 24 miRNAs at GD42, and 43 miRNAs at GD75. Bioinformatic analysis revealed that a number of differentially expressed miRNAs are predicted to target genes known to be important in mammalian gonadal development, including <it>ESR1, CYP19A1</it>, and <it>SOX9</it>. In situ hybridization revealed <it>miR-22 </it>localization within fetal testicular cords. As estrogen signaling is important in human and sheep ovarian development, these data indicate that miR-22 is involved in repressing estrogen signaling within fetal testes.</p> <p>Conclusions</p> <p>Based on our results we postulate that gene expression networks underlying fetal gonadal development are regulated by miRNAs.</p

Soaking grapevine cuttings in water: A potential source of cross contamination by micro-organisms

Grapevine nurseries soak cuttings in water during propagation to compensate for dehydration and promote root initiation. However, trunk disease pathogens have been isolated from soaking water, indicating cross contamination. Cuttings of Vitis vinifera cv. Sunmuscat and V. berlandieri x V. rupestris rootstock cv. 140 Ruggeri were immersed in sterilized, deionised water for 1, 2, 4, 8 and 16 h. The soaking water was cultured (25°C for 3 days) on non-specific and specific media for fungi and bacteria. The base of each cutting was debarked and trimmed and three 3 mm thick, contiguous, transverse slices of wood cultured at 25°C for 3 days. The soaking water for both cultivars became contaminated with microorganisms within the first hour. Numbers of fungi isolated from the wood slices soaked for one hour were significantly greater than those from non-soaked cuttings. The number of bacterial colonies growing from the wood slices increased after soaking for 2-4 h in Sunmuscat. In a second experiment Shiraz cuttings were soaked for 1, 2, 4, 8 and 24 h. The soaking water became contaminated within the first hour but only the bacterial count increased significantly over time. Microorganisms also established on the container surfaces within the first hour although there were no significant increases over 24 h. These results confirm that soaking cuttings is a potential cause of cross contamination and demonstrate contamination of cuttings occurs after relatively short periods of soaking. Avoiding exposing cuttings to water will reduce the transmission of trunk diseases in propagation. © Firenze University Press.Financial support by the ‘Programa de apoyo a la Investigación y Desarrollo (PAID-00-10) de la Universidad Politécnica de Valencia’ for David Gramaje during his three months in Australia is gratefully acknowledged. Financial support by Charles Sturt University and the Grape and Wine research and development Corporation for Helen Waite is also gratefully acknowledged.Peer Reviewe

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Detection of Biomarkers Relating to Quality and Differentiation of Some Commercially Significant Whole Fish Using Spatially Off-Set Raman Spectroscopy

Aquaculture represents a major part of the world&rsquo;s food supply. This area of food production is developing rapidly, and as such the tools and analytical techniques used to monitor and assess the quality of fish need to also develop and improve. The use of spatially off-set Raman spectroscopy (SORS) is particularly well-suited for these applications, given the ability of this technique to take subsurface measurements as well as being rapid, non-destructive and label-free compared to classical chemical analysis techniques. To explore this technique for analysing fish, SORS measurements were taken on commercially significant whole fish through the skin in different locations. The resulting spectra were of high quality with subsurface components such as lipids, carotenoids, proteins and guanine from iridophore cells clearly visible in the spectra. These spectral features were characterised and major bands identified. Chemometric analysis additionally showed that clear differences are present in spectra not only from different sections of a fish but also between different species. These results highlight the potential application for SORS analysis for rapid quality assessment and species identification in the aquaculture industry by taking through-skin measurements

Whey Protein Peptides Have Dual Functions: Bioactivity and Emulsifiers in Oil-In-Water Nanoemulsion

Whey protein isolate (WPI)-derived bioactive peptide fractions (1–3, 3–5, 5–10, 1–10, and >10 kDa) were for the first time used as emulsifiers in nanoemulsions. The formation and storage stability of WPI bioactive peptide-stabilized nanoemulsions depended on the peptide size, enzyme type, peptide concentration, and storage temperature. The highly bioactive 10 kDa fractions formed stable nanoemulsions (diameter = 174–196 nm); however, their performance was dependent on the peptide concentration (1–4%) and enzyme type. Overall, nanoemulsions exhibited better storage stability (less droplet growth and creaming) when stored at lower (4 °C) than at higher (25 °C) temperatures. This study has shown that by optimizing peptide size using ultrafiltration, enzyme type and emulsification conditions (emulsifier concentration and storage conditions), stable nanoemulsions can be produced using WPI-derived bioactive peptides, demonstrating the dual-functionality of WPI peptides

Volatile and sensory profiling of Shiraz wine in response to alcohol management: comparison of harvest timing versus technological approaches

The aim of this study was to compare the volatile and sensory profiles of Australian Shiraz red wines produced by several methods to achieve alcohol concentrations of 10.5 and 13.5% v/v. These levels were considerably lower contents than the commercial wine (16-17% v/v) that was produced from this vineyard site. Wines were produced by: (i) harvest timing (19.3, 24 and 29.3 Brix); (ii) blending equal proportions of early harvest (19.3 Brix) and late harvest wines (29.3 Brix); and (iii) dealcoholization using reverse osmosis followed by a membrane contactor. Dealcoholization caused a significant loss of volatile compounds, particularly esters, while the blending treatment had an averaging effect on most analytes. Sensory descriptive analysis of treatments with 10.5% v/v alcohol showed that the perception of the herbaceous attribute was more intense in the early harvest wines in comparison to the dealcoholized wines, while those of dark fruit, raisin/prune, astringency and alcohol were lower. No sensory differences were found amongst the 13.5% v/v wines, except for alcohol. Sensory and compositional data were modelled by means of Common Dimension (ComDim) multi-block analysis and indicated which chemical components are important to the perceived wine sensory properties. Insights from this study will provide knowledge that may be applied to control or moderate both unripe sensory attributes in addition to a deficiency of ripe fruit aromas or mouthfeel characteristics in reduced-alcohol red wines

Changes in volatile composition and sensory attributes of wines during alcohol content reduction

A desirable sensory profile is a major consumer driver for wine acceptability and should be considered during the production of reduced-alcohol wines. Although various viticultural practices and microbiological approaches show promising results, separation technologies such as membrane filtration, in particular reverse osmosis and evaporative perstraction, in addition to vacuum distillation, represent the most common commercial methods used to produce reduced-alcohol wine. However, ethanol removal from wine can result in a significant loss of volatile compounds such as esters (ethyl octanoate, ethyl acetate, isoamyl acetate) that contribute positively to the overall perceived aroma. These losses can potentially reduce the acceptability of the wine to consumers and decrease their willingness to purchase wines that have had their alcohol level reduced. The change in aroma as a result of the ethanol removal processes is influenced by a number of factors: the type of alcohol reduction process; the chemical-physical properties (volatility, hydrophobicity, steric hindrance) of the aroma compounds; the retention properties of the wine non-volatile matrix; and the ethanol level. This review identifies and summarises possible deleterious influences of the dealcoholisation process and describes best practice strategies to maintain the original wine composition