Diagnostics of plasma reactive species and induced chemistry of plasma treated foods.

Cold plasma is a promising technique that has been tested as a process technology for a range of food commodities, mainly to destroy microorganisms, but also aimed at toxin degradation, enzyme inactivation, residual pesticide degradation and functionalization of food properties. Plasma has already been employed by industry for food packaging material sterilization and surface modification. As most of the current literature on cold plasma in the field of food science is focused on microbial inactivation efficacy, the information about its chemical influences on food is sparse. To better understand the chemical interactions of with plasma, this review focuses on plasma chemistry diagnostics techniques available to characterize the plasma reactive species generated. Equally important is the detection of induced chemistry in the food and here we present approaches to analyze likely reactions with key food bio-molecules. Such analysis will support mechanistic insights involved in these complex chemical reactions (i.e., DNA, lipid and protein) along with potential physical modifications of the food structure. For successful adoption of plasma as a food processing aid it is critical to elucidate these interactions as they have an important role in demonstrating the technology's safety as a food processing technique along with understanding any effect on food nutrients.

Enhancement of phytochemical content and drying efficiency of onions (Allium cepa L.) through blanching.

BACKGROUND: This study investigated the effect of blanching (60, 70 and 80 °C for 1, 3, 5 and 10 min) combined with oven drying at 60 °C on the phenolic compounds, antioxidant activity, colour and drying characteristics (drying time, drying rate constant, effective moisture diffusivity and activation energy) of onion slices. RESULTS: Blanching of onion slices at 60 °C for 3 min and at 70 °C for 1 min prior to drying increased their bioactive compounds and antioxidant activity compared to the control samples and other treatments. Eighteen drying models were evaluated. The Modified Page and two-term exponential models best represented the drying data. The effective diffusivity ranged from 3.32 × 10-11 m2 s-1 (control) to 5.27 × 10-11 m2 s-1 , 5.01 × 10-11 m2 s-1 , and 4.74 × 10-11 m2 s-1 for onions blanched at 60 °C, 70 °C and 80 °C, respectively. The higher activation energy was observed for the control (unblanched) sample and slightly lower values were found for 1 min- and 3 min-blanched samples, confirming the higher drying efficiency as a result of the blanching pre-treatment. CONCLUSION: The use of blanching as a pre-treatment before drying of onions resulted in enhanced phytochemical content and drying efficiency. © 2017 Society of Chemical Industry.

Valorization of Apple Pomace by Extraction of Valuable Compounds.

Apple pomace is a promising source of carbohydrates, proteins, amino acids, fatty acids, phenolic compounds, vitamins, and other compounds with a vast range of food applications. This review focuses on the valorization of apple pomace towards the recovery of the main compounds, namely pectin and polyphenols. Applications, advantages, and drawbacks of conventional extraction (acidic medium under high temperatures) compared with novel extraction technologies are presented. The comparison is based on an extensive literature review of research on extraction of valuable compounds from plant matrixes, particularly apple pomace. Novel extraction techniques involving enzymes, electric field, ultrasound, microwave heating, pressurized liquid, and super/subcritical fluid are also discussed. These techniques offer several advantages, including shorter extraction time, increased yield, reduction-or suppression-of solvents, and minimization of the environmental impact. This paper may help researchers and food industry professionals on the scaling-up and optimization of eco-friendly extractions of pectin and phenolic compounds.

Impact of Industrial Practices on the Microbial and Quality Attributes of Fresh Vacuum-Packed Lamb Joints.

The impact of different industrial practices at lamb export abattoirs in Ireland on the microbial and quality attributes of fresh vacuum-packed (VP) lamb leg joints, including Clean Livestock Policy (CLP), fleece clipping, carcass chilling times and vacuum pack storage, at typical chill and retail display temperatures was investigated. Five separate slaughter batches of lamb (ranging in size from 38 to 60 lambs) were followed at two lamb export plants over a two-year period, accounting for seasonal variation. In general, fleece clipping resulted in significantly lower microbial contamination on the fleece than the use of CLP alone. Lamb from carcasses chilled for 24 h had significantly lower psychrophilic total viable counts and Brochothrix thermosphacta and pseudomonad counts than carcasses chilled for 72 h. Following vacuum-packed (VP) storage of meat from these carcasses at 1.7 ± 1.6 °C for 23 days in the meat plant followed by retail display at 3.9 ± 1.7 °C (up to day 50), the dominant microorganisms were lactic acid bacteria, Br. thermosphacta, Enterobacteriaceae and pseudomonads, and all had reached maximum population density by storage day 34. Aligned with this, after day 34, the quality of the raw meat samples also continued to deteriorate, with off-odours and colour changes developing. While the mean values for cooked meat eating quality attributes did not change significantly over the VP storage period, high variability in many attributes, including off-flavours and off-odours, were noted for lamb meat from all storage times, highlighting inconsistences in lamb quality within and between slaughter batches.

Kinetic modelling of ultrasound-assisted extraction of phenolics from cereal brans.

Cereal brans are by-products of the milling of cereal grains, which are mainly used as low value ingredients in animal feed. Wheat and oat bran is a rich source of bioactives and phytochemicals, especially phenolic compounds. Within this study, the application of ultrasound (US) technology to assist the extraction of phenolics from oat and wheat bran was investigated (20-45 kHz). Peleg's mathematical model was used to study the kinetics of ultrasound-assisted extraction (UAE) and subsequent stirring of total phenolic compounds (TPC). The surface morphology of cereal brans after extraction was studied using SEM analysis. The excellent agreement was determined between the values of TPC calculated from Peleg's mathematical model and actual experimental results. The constant that represents a time required for the initial phenolic concentration to be extracted to one-half of its initial value has been introduced (K1/2). It was shown that the TPC extraction kinetics was dependent only on K1/2 enabling fast kinetics fitting and comparison between extraction rates. Moreover, different values of K1/2 constant could indicate the differences in brans composition and consequently different influence of US pretreatment on these samples.

Effect of storage, food processing and novel extraction technologies on onions flavonoid content: A review.

Onions play an important part in the daily diet for most populations around the world owing to their nutritional composition and their unique capacity to naturally flavor dishes. Onions contain quercetin and its derivatives - the predominant flavonoid in onions that exert a great contribution to the effective bioactive properties of onion, including its derived products. The present paper comprehensively reviewed flavonoids (with a specific focus on quercetin in onions): their chemical composition, distribution, bioactivities in onion, and impacting factors with a focus on how they can be affected by various post-harvest conditions (storage and food processing). In addition, research on the extraction of flavonoid compounds from onions using a number of novel technologies was also reviewed.

Chemical modification of citrus pectin: Structural, physical and rheologial implications.

The present study aimed to investigate the physical, structural and rheological modifications caused by the chemical modification process of citrus pectin. Therefore, three commercial citrus pectins with different degree of esterification were chemically modified by sequential alkali and acidic hydrolytic process to produce modified citrus pectins (MCP) with special properties. The molar mass (Mw), degree of esterification (DE), monosaccharide composition, 13C NMR spectra, homogeneity, morphology (SEM) and rheological behavior of both native and modified citrus pectins (MCP) were investigated. The chemical modification reduced the acid uronic content (up to 28.3%) and molar mass (up to 29.98%), however, showed little influence on the degree of esterification of native pectins. Modified citrus pectins presented higher amounts of neutral monosaccharides, mainly galactose, arabinose and rhamnose, typical of the Ramnogalacturonana-I (RG-I) region. Rheological tests indicated that the native and modified citrus pectins presented pseudoplastic behavior, however, the MCP samples were less viscous, compared to the native ones. Modified samples presented better dissolution in water and less strong gels, with good stability during oscillatory shearing at 25°C. This study aims to better understand the implications that chemical modifications may impose on the structure of citrus pectins.

Ultrasonic-assisted incorporation of nano-encapsulated omega-3 fatty acids to enhance the fatty acid profile of pork meat.

In this study, ultrasound was employed to enhance the diffusion of microencapsulated fatty acids into pork meat. Nanovesicles of fish oil composed of 42% EPA (eicosapentanoic acid) and 16% DHA (docosahexanoic acid) were prepared using two different commercial Pronanosome preparations (Lipo-N and Lipo-CAT; which yield cationic and non-cationic nanovesicles, respectively). The thin film hydration (TFH) methodology was employed for encapsulation. Pork meat (Musculus semitendinosus) was submerged in the nanovesicles suspension and subjected to ultrasound (US) treatment at 25kHz for either 30 or 60min. Samples were analysed for fatty acid composition using gas chromatography-flame ionisation (GC-FID). The content of long-chain PUFAs, especially omega-3, was found to increase following the US treatment which was higher for Lipo-CAT compared to Lipo-N nanovesicles. Samples subjected to Lipo-N had higher atherogenic and thrombogenic indices, indicating higher levels of saturated fatty acids compared to the Lipo-CAT. The omega-6/omega-3 ratio in pork meat was significantly reduced following the US treatment, thus indicating an improved fatty acid profile of pork.

ASSESSMENT OF THE OSMO-CONVECTIVE DEHYDRATION ON THE QUALITY ATTRIBUTES AND CENTESIMAL COMPOSITION OF YACON (Smallanthus sonchifolius)

This work has studied the application of the osmo-convective dehydration on yacon roots, regarding its composition and quality attributes. Slices of yacon were submitted to osmotic treatment with sucralose solution followed by convective dry. The experiments followed a complete 23 factorial design to assessthe effect of three variables of the process (temperature, stirring rate of the osmotic solution and drying temperature) over four quality attributes (moisture content, color, luminosity and soluble solid content). The application of the osmotic treatment before convective drying provided quality gains to the dried product, such as low browning and shrinkage rates, and reduction of the structural damages towards angular distortions and fissures, in comparison to the samples dried directly on the tray dryer. The effect of osmotic treatment over the centesimal composition of yacon have resulted on absorption of sucralose and water loss without a significance compromise of its nutritional attributes. The obtained product presented different contents of moisture, but similar levels of darkening and color alteration at diverse experimental conditions.

Investigou-se a aplicação da desidratação osmo-convectiva em raízes de yacon, com relação à sua composição centesimal e atributos de qualidade. Fatias de yacon foram submetidas ao tratamento osmótico em solução de sucralose e depois à secagem convectiva. Os experimentos seguiram planejamento fatorial completo (2