Comprehensive profiling of lipid oxidation volatile compounds during storage of mayonnaise

Lipid oxidation is a primary cause of quality deterioration in mayonnaise that leads to a decrease in the nutritional and sensorial value. The evolution of volatile oxidation compounds in sunflower oil mayonnaise stored at varying temperatures for 92\ua0days and the antioxidative effect of butylated hydroxyanisole were investigated by static headspace extraction and separation by two dimensional gas chromatography/time-of-flight mass spectrometry. Considerable differences in the headspace composition of samples stored at 4, 25 and 38\ua0°C were found due to the different oxidation levels reached. The content of hexanal in mayonnaise at 1–5\ua0days of storage at 38\ua0°C could be used to predict the corresponding compound in mayonnaise at 1–62\ua0days of storage at 25\ua0°C. The 10 most important discriminating volatile compounds during lipid oxidation of mayonnaise (at 38\ua0°C for 92\ua0days) are 3-hexenal, pentanal, 2-heptenal, 2-ethylfuran, hexanal, benzeneacetaldehyde, 2-pentylfuran, 3-methylhexane, 1-pentanol and 2,4-heptadienal. More than half of these compounds have a close relationship with the initial content of linoleic acid that agrees with the fatty acid profile of sunflower oil (~ 70% linoleic acid). These volatiles could be used as additional markers of oxidation in sunflower oil mayonnaise

Effect of natural antioxidants on lipid oxidation in mayonnaise compared with BHA, the industry standard

Mayonnaise is an oil in water emulsion (O/W) consisting 70-80% oil. Lipid oxidation is a major cause of quality deterioration in mayonnaise. The effectiveness of antioxidants in a hetrophasic systems is highly dependent on their polarity and partitioning properties.The aim of the present study was to determine the effect of a hydrophilic [green tea extract (GTE)] and a lipophilic [tocopherol mixture (TOC)] and BHA on lipid oxidation in mayonnaise during 60\ua0days of storage at 38\ua0°C and to examine the interactions between GTE and TOC, to determine possible synergistic or antagonistic effects in antioxidant activity.The oxidative stability was studied by measuring hydroperoxides, volatile organic compounds (VOCs) and colour of mayonnaise during storage. Comprehensive analysis of VOCs was done by static headspace extraction and separation by two-dimensional gas chromatography time of flight mass spectrometry. Sensory analysis was also carried out to study the effect of storage time and antioxidant type on sensory properties of mayonnaise and to investigate the predictive ability of volatile compounds for sensory terms.Addition of GTE (500\ua0ppm) and TOC (500\ua0ppm) increased the formation of hydroperoxides and certain VOCs. The combination of GTE with TOC improved the antioxidant efficacy compared to the individual extracts. However, sensory evaluation demonstrated that GTE promoted the development of unpleasant fishy and rancid aroma. The volatile compound methional, was significantly and positively correlated with fishy and rancid flavour. Regarding colour analysis, GTE showed the highest increase in darkening and browning during storage

Rice biparental population GBS dataset

DNA was extracted from leaf tissue of Apo, IR64 and all 213 lines of the population and submitted to Cornell University for genotyping by sequencing analysis using an Illumina HiSeq instrument. SNP calls were made using the variety Nipponbare as reference

Recent advances in NMR-based metabolomics of alcoholic beverages

Alcoholic beverages have a complex chemistry that can be influenced by their alcoholic content, origin, fermentation process, additives, and contaminants. The complex composition of these beverages leave them susceptible to fraud, potentially compromising their authenticity, quality, and market value, thus increasing risks to consumers’ health. In recent years, intensive studies have been carried out on alcoholic beverages using different analytical techniques to evaluate the authenticity, variety, age, and fermentation processes that were used. Among these techniques, NMR-based metabolomics holds promise in profiling the chemistry of alcoholic beverages, especially in Asia where metabolomics studies on alcoholic beverages remain limited

Lipidomics reveals associations between rice quality traits

Introduction: Lipids are a diverse group of macromolecules that occur in rice grains and are known to impact rice grain properties. Identifying the relationships between specific lipids and traits of quality is important to improve varietal selection for high quality rice. Objectives: Using untargeted lipidomics, this study aims to understand the role of lipids on different traits of quality by identifying the genotypic effect of lipids and their impact on traits of cooking and eating quality of a rice mapping population. Methods: Lipids from milled rice grains of three sets of rice samples were screened by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) in the positive ionisation mode. Lipid features were putatively identified using analytical standards and online databases. Multivariate statistics were carried out to identify the lipid profile of varieties across three experiments. Correlation analysis was carried out between lipid features and 12 quality traits across a rice mapping population that segregates for grain physical and texture-associated traits. Results: Thousands of features in rice grain lipids were detected, and were grouped into six categories—fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids and prenol lipids. A strong genotypic basis for the lipid profile was observed among the four varieties grown under five nitrogen treatments. Clear differentiation in lipid profiles between waxy and non-waxy rice was observed. Strong correlations were observed for putative lipids that form the amylose–lipid complex and with amylose content and viscosity parameters. Conclusions: This study demonstrates the strength of untargeted lipidomics in putatively determining features that differentiate varieties from each other, and reveals the role of specific lipids on the physical and textural quality of rice. © 2020, Springer Science+Business Media, LLC, part of Springer Nature

Yield and quality of traditional and improved Lao varieties of rice

Improvements in its political and tourism sectors have encouraged Lao PDR to explore export options for its traditional waxy rice varieties. As such, farmers and agriculturists are exploring ways to enhance yield and capture high-quality traits into improved varieties such as Thasanol (TSN1) and Thadokkhaml (TDK1). In this study, the effects of nitrogen (N) on yield and quality traits were investigated in two traditional varieties, Hom Nang Nouane (HNN) and Kai Noy Leuang (KNL), and in two popular improved varieties, TDK1 and TSN1. The plants were cultivated during the 2006 wet season at the Rice and Cash Crop Research Centre, NAFRI, Lao PDR, and were subjected to four N rates. Results showed that while increased N rates enhanced yields and yield components in TDK 1 and TSN1, the two traditional varieties, HNN and KNL, were not as responsive. In contrast, the quality traits assessed in this study of the four varieties were not affected by N. Yield and textural attributes further suggest that TSN1 is a better candidate than TDK 1 for breeding programs aimed at combining quality traits from HNN and KNL into improved varieties

Chlorinated hydrocarbons in sediments from Manila Bay, the Philippines

Polychlorobiphenyls (PCBs) and organochlorine pesticides were analysed in sediments collected during the summer monsoon period (rainy season) in order to assess the contamination of Manila Bay. Results were compared with previous determinations made during the winter monsoon period (dry season) in order to evaluate seasonal fluctuation of contaminant levels in the Bay. In both seasons, PCBs were present in concentrations higher than chlorinated pesticides. In the rainy season the median concentration of ΣPCB was 0.256 ng g dry weight (range 0.08-1.173 ng g), followed by ΣDDT with 0.229 ng g dry weight (range 0.133-0.926 ng g) and Σchlordane with 0.049 ng g dry weight (range 0.024-0.175 ng g). Concentrations of chlorinated hydrocarbons in sediments were relatively low and, when concentrations determined in the rainy season and in the dry season were compared, in general, they did not show seasonal fluctuation with the exception of DDTs. Round the year, levels of these toxic, persistent and bioaccumulative contaminants in Manila Bay sediments were below threshold effect levels for marine biota

Organic contaminants in the marine environment of manila bay, philippines

Organochlorine pesticides (OCs) and polychlorobiphenyls (PCBs) were determined in sediments and oysters' soft tissues (Cassostrea gigas) collected in selected sites of Manila Bay. Overall, the concentration levels were very low. In sediments, PCBs were the compounds present in higher concentrations, with ∑13PCB congeners averaging 0.69 ± 0.46 ng/g (dry weight), followed by ∑DDT averaging 0.53 ± 0.28 ng/g and ∑chlordane with 0.26 ± 0.28 ng/g. Concentrations measured in oysters averaged 20 ± 17 ng/g (dry weight) for ∑13PCB and were higher than ∑DDT, with 9.5 ± 2.4 ng/g, and ∑chlordane, with 3.8 ± 3.1 ng/g. No dissolved residues of polar compounds, such as herbicides, and organophosphorous and organochlorine pesticides were found in the bay water. In general, results showed that concentrations of organochlorine pesticide residues, such as DDT, hexachlorocyclohexane, chlordane, lindane, endosulfan, and heptachlor in sediments and oysters were low in comparison with other coastal areas in Asia, although PCB concentrations in oysters were relatively high in some zones of Manila Bay and indicative of loose control of industrial chemical waste discharges into the bay. Nevertheless, current concentrations of persistent organochlorine contaminants in sediments were under threshold effect levels (TELs) and chronic toxic effects are, thus, unlikely to generate impairment of marine biota in Manila Bay

Understanding the Jasmine phenotype of rice through metabolite profiling and sensory evaluation

Introduction: Aromatic rices are culturally and economically important for many countries in Asia. Investigation of the volatile compounds emitted by rice during cooking is the key to understanding the flavour of elite aromatic rice varieties. Objectives: The objectives of this study were to compare Jasmine-type aromatic rices from the Greater Mekong Subregion and Australia in terms of their metabolomics and sensory profiles and to draw out associations between the volatile organic compounds and human sensory perception of rice aroma. Methods: A set of aromatic rice varieties from South East Asia and Australia, along with non-aromatic controls, was grown in tropical and temperate areas of Australia. Untargeted metabolite profiling of volatile compounds, from the heated rice flour, by static headspace extraction and separation by two dimensional gas chromatography time-of-flight mass spectrometry was performed. Volatile compounds were also assayed in the standard references used in the sensory evaluation and compared to the compounds detected in the headspace of rice. Results: While 2-acetyl-1-pyrroline (2-AP) was a discriminating compound, we identified several of its structural homologues, and a number of other metabolites that were consistently detected in fragrant Jasmine rice. 2-AP producing rice varieties have different sensory properties and these variations were defined by the discriminating compounds identified in each rice type. Conclusions: The results of this study are valuable in understanding the aspects of aromatic rice that are important to consumers, and in the identification of compounds that breeding programs can use to select for pleasant aromas, enabling breeding programs to target markets with greater accuracy