B. R. D'Arcy

Effect of high power ultrasound and ageing on the physical properties of bovine Semitendinosus and Longissimus muscles

Tenderness is an important meat quality parameters and the use of high power ultrasound to disrupt muscle structure may prove effective for reducing both myofibrillar and collagenous toughness. The experiment was carried out with Longissimus lumborum et thoracis and Semitendinosus muscles from 3 to 4 year old steers. Uncooked beef samples (60×40×20mm) were treated with high power ultrasound (24kHz, 12W/cm(2)) for up to 240s, and aged for up to 8.5 days before evaluation of pH, drip loss, cook losses Warner-Bratzler shear (WBS), compression hardness, and colour. Ultrasound treatment significantly reduced WBS force and hardness, but significantly increased pH. Ageing significantly reduced hardness and WBS force, but there was no significant interaction between ultrasound treatment and ageing time. Ultrasound treatment did not affect any of the colour parameters (L(∗)a(∗)b(∗), chroma and hue) but the ageing time significantly increased the lightness, chroma and hue. There was no significant effect of ultrasound treatment on drip loss, but it did significantly reduce the cook and total loss. During ageing, cook loss and total losses significantly increased. The results suggest that high power ultrasound is capable of reducing objective texture measurements of beef without compromising the other quality parameters investigated.

Effect of High Power Ultrasound Waves on Properties of Meat: A Review

Abstract The effect of high power ultrasound waves on physical, biochemical, and microbial properties of meat have been the subject of a great deal of interest in recent years. The present review details the basic principles underlying the effects of ultrasound on the properties of food systems, followed by discussion of specific effects of high power ultrasound on meat products, including muscle, cellular, and subcellular components. In addition, the specific effects of high power ultrasound on the following parameters are discussed: enzyme activities and efficiencies, muscle proteolysis, quality criteria such as tenderness; extraction of protein, gelation, and restructuring of meat products and germicidal properties against meat micro-organisms.

Honey quality and international regulatory standards: review by the International Honey Commission

International honey standards are specified in a European Honey Directive and in the Codex Alimentarius Standard for Honey, both of which are presently under revision. In this article, present knowledge on the different quality criteria is reviewed. The standard drafts include standards and methods for the determination of the following quality factors: moisture, ash, acidity, HMF, apparent reducing sugars, apparent sucrose, diastase activity and water-insoluble matter. International honey standards for fructose/glucose content, the sucrose content and electrical conductivity are proposed. Also the use of other quality factors, such as invertase activity, proline and specific rotation, used in many countries, is also discussed.

Rheology of selected Australian honeys

The viscosity property of seven varieties of commercial Australian honeys (yellow box, tea tree, leatherwood, red gum, iron bark, strawberry clover and creamed) were analysed over a range of temperatures (4-30 degrees C). All of these honey varieties exhibited Newtonian behaviour. The temperature effect on the viscosity followed an Arrhenius-type relationship. The activation energy ranged from approx. 1250-1850 J/g mole

Role of intestinal microbiota in the generation of polyphenol-derived phenolic acid mediated attenuation of Alzheimer's disease β-amyloid oligomerization.

SCOPE Grape seed polyphenol extract (GSPE) is receiving increasing attention for its potential preventative and therapeutic roles in Alzheimers disease (AD) and other age-related neurodegenerative disorders. The intestinal microbiota is known to actively convert many dietary polyphenols, including GSPE, to phenolic acids. There is limited information on the bioavailability and bioactivity of GSPE-derived phenolic acid in the brain. METHODS AND RESULTS We orally administered GSPE to rats and investigated the bioavailability of 12 phenolic acids known to be generated by microbiota metabolism of anthocyanidins. GSPE treatment significantly increased the content of two of the phenolic acids in the brain: 3-hydroxybenzoic acid and 3-(3´-hydroxyphenyl)propionic acid, resulting in the brain accumulations of the two phenolic acids at micromolar concentrations. We also provided evidence that 3-hydroxybenzoic acid and 3-(3´-hydroxyphenyl)propionic acid potently interfere with the assembly of β-amyloid peptides into neurotoxic β-amyloid aggregates that play key roles in AD pathogenesis. CONCLUSION Our observation suggests important contribution of the intestinal microbiota to the protective activities of GSPE (as well as other polyphenol preparations) in AD. Outcomes from our studies support future preclinical and clinical investigations exploring the potential contributions of the intestinal microbiota in protecting against the onset/progression of AD and other neurodegenerative conditions.

Rheology and crystallization kinetics of honey: Present status

Abstract Crystallization property of honey is a matter of interest for beekeepers, honey handlers and processors. Honey is basically a sugar syrup with about 16‐18% moisture content (wet basis). The composition and rheology are some of the important parameters that influence the crystallization behavior of honey. At present, most of the crystallization prediction methods are based on the composition considering honey as a glucose‐fructose‐water system. This review paper presents current methods used to predict honey crystallization and puts forward a hypothesis based on viscosity and glass transition temperature.

Volatile Sulphur Compounds in UHT Milk

Several volatile sulphur compounds have been detected in raw and processed milk. These are hydrogen sulphide, methanethiol, carbonyl sulphide, dimethyl sulphide, carbon disulphide, dimethyl disulphide, dimethyl trisulphide, dimethyl sulphoxide, and dimethyl sulphone. Many of these increase in milk during heat processing and are associated with the cooked flavor of heat-treated milks, particularly UHT and sterilized milk. Several researchers have attempted to explain the origin of these volatiles in both raw and processed milk, and how to reduce the associated cooked flavor that has a negative impact on consumer acceptability of processed milk. These compounds are difficult to detect and analyze due to their high volatility, sensitivity to oxidation and heat, and in some cases, their very low concentrations. However, methods of detection and quantification have improved in recent years. Pre-concentration methods such as solid phase microextraction (SPME) together with gas chromatography equipped with sulphur-selective detectors now enable low concentrations of these compounds to be analyzed. In this review, methods of extraction and analyzis of these volatile sulphur compounds are comared, and their occurrence in milk is reviewed.

The effect of ionic strength, polyphosphates type, pH, cooking temperature and preblending on the functional properties of normal and pale, soft, exudative (PSE) pork.

Compared to processed meat product made from normal pork, products made from pale soft exudative (PSE) pork have higher cook loss (CL) and weaker texture. In this study interactions between a range of processing conditions (ionic strength, polyphosphate addition, polyphosphate chain length, pH, cooking temperature and time between preparation and cooking), and their effect on the texture [shear stress (SS), true shear strain (TSS)] and CL of gels made from normal and PSE pork were examined. Of the processing conditions studied, ionic strength, polyphosphate addition and polyphosphate chain length affected the functional properties of normal and PSE pork differently. Generally, the functional properties of normal pork were superior to PSE pork, with no combination of conditions making all the functional properties of PSE pork equal to those of normal pork under the same conditions. The combination of conditions that was most effective in reducing the difference between normal and PSE pork was high ionic strength in the presence of added polyphosphate. Under these conditions there was no significant difference in CL between normal and PSE pork, although the texture (SS and TSS) of the PSE pork samples was still inferior.

Binding of dietary polyphenols to cellulose: Structural and nutritional aspects

The interactions between polyphenols and plant fibres play an important role in controlling the release of phenolic compounds from food matrices for absorption in the gastrointestinal tract. This study probed the molecular interactions of diverse polyphenols with cellulose fibres by using a pure cellulose-producing bacterial model. Alkali treatment of bacterial cellulose was an effective method for obtaining a high purity cellulose model for study of polyphenol binding. Representatives of different polyphenol classes all bound to cellulose spontaneously, rapidly, and to comparable extents (up to 60% w/w of cellulose). Langmuir binding isotherms were applied to determine quantitative aspects of the adsorption at equilibrium. The study indicated that binding was similar on a molar basis for ferulic acid, gallic acid, catechin and cyanidin-3-glucoside (but lower for chlorogenic acid), with the native charge of polyphenols a secondary factor in the interactions between polyphenols and cellulose.

Phenolic Contents and Antioxidant Activities of Major Australian Red Wines throughout the Winemaking Process

Three Australian red wine types (Shiraz, Cabernet Sauvignon, and Merlot) were analyzed for antioxidant activity and a range of phenolic component contents using various spectral methods. More than half of the total phenolic compounds were tannins, whereas monomeric anthocyanins and flavonols were present in much lesser amounts (<10%). The evolution of phenolic contents and the respective antioxidant activities in wine samples from all stages of winemaking showed progressive changes toward those of commercial wines. The antioxidant activity of the wines in DPPH and ABTS assays was positively correlated with total phenolic contents and tannins. Comparisons of the three wine varieties based on their individual phenolic component groups and antioxidant activities showed limited differences between the different varieties. However, when all of the variables were combined in a principal component analysis, variety differentiation was observed. The three varieties of red wines all contained similar and high concentrations of antioxidants despite differences in grape variety/maturity and winemaking process, suggesting that related health benefits would accrue from all of the red wines studied.