Headspace solid‐phase micro extraction coupled to comprehensive two‐dimensional with time‐of‐flight mass spectrometry applied to the evaluation of Nebbiolo‐based wine volatile aroma during ageing

This study presents the application of a headspace solid‐phase microextraction (HS‐SPME) method on the analysis of Nebbiolo‐based wine volatiles by comprehensive two‐dimensional gas chromatography (GC×GC) and time‐of‐flight mass spectrometry (TOF‐MS). The aroma patterns were established for different samples of Nebbiolo‐based wines, aged in oak wood barrels for 18 months at constant temperature. The methodology allowed for the simultaneous analysis of over 130 different volatile compounds detected in the headspace. The odour activity values (OAVs) were assessed to identify potentially important odorants of Nebbiolo‐based wine during ageing. The highest OAVs were obtained for several compounds such as ethyl octanoate, ethyl hexanoate, isoamyl acetate, β‐damascenone, ethyl cinnamate, ethyl 3‐methylbutanate and acetaldehyde. Ethyl butanoate, octanoic acid, ethyl dihydrocinnamate and γ‐nonalactone were also at concentrations higher than their corresponding threshold. Also vanillin, (E)‐whisky lactone, (Z)‐whisky lactone, guaiacol and 4‐ethyl guaiacol seem to be important odorants after oak wood ageing period.     

Sensory and Chemical Analysis of ‘Shackleton's’ Mackinlay Scotch Whisky

Three cases of Mackinlay's Rare Highland Malt whisky were excavated from the ice under Sir Ernest Shackleton's 1907 expedition base camp hut at Cape Royds in Antarctica in January 2010. The majority of the bottles were in a pristine state of preservation and three were returned to Scotland in January 2011 for the first sensory and organoleptic analysis of a Scotch malt whisky distilled in the late 1890s. Sensory analysis and the higher alcohol and maturation congener profiles describe a lightly peated malt whisky matured in American white oak sherry or wine casks. Analysis of process related compounds together with combined gas chromatography (GC) mass spectrometry and GC‐olfactometry analysis of fermentation related congeners show a distinctly ‘modern’ style of malt whisky. While Scotch malt whisky at the end of the 19th century was generally regarded as heavily peated and harsh in character, Charles Mackinlay & Co. Distillers were producing a malt whisky with an altogether more subtle character at their Glen Mhor distillery near Inverness. The sensory and chemical analysis of this unique whisky artefact significantly changes our understanding of the quality and character of Scotch malt whisky produced by our distilling forefathers.     

Volatile flavor release from foods during eating

Classical analyses for volatile flavors (headspace or distillation/extract methods) give information on either the volatiles present in the air above a food before eating or the total volatile composition of the food. When foods are eaten, however, many changes take place (such as hydration/dilution with saliva, increase in surface area, etc.) that affect the release of volatiles from the food and therefore the profile of volatiles that are sensed in the nose. If we wish to study the relationship between flavor volatiles and the sensory properties of a food, it seems logical to measure the volatile profile that exists during eating. Although volatile flavor release during eating has been measured using a variety of sensory and psychophysiological analyses, only recently have instrumental methods been developed to measure the release of volatile compounds in humans as they eat. Whereas the sensory data give an overall measure of flavor perception, instrumental analyses can potentially follow the release of each and every flavor volatile and thus give a full picture of the aroma profiles generated during eating. From these instrumental measurements, a number of key factors have been identified. First, it has been shown that the volatile profile measured during eating is indeed different from the headspace profile of whole foods. Second, it is clear that the volatile profile in‐mouth changes with time as the state of the food changes with chewing. Third, the volatile release from low‐water foods is affected by the rate and extent of hydration in‐mouth. The ability to measure aroma before, during, and after eating may lead to an understanding of the links between aroma release, interaction of volatiles with aroma sensors in the nose, and the overall perception of food flavor.     

国产威士忌加工过程中挥发性成分的变化及风味的形成

为研究国产威士忌顶空中的挥发成分形成的关键阶段，本文采用静态顶空-气相色谱质谱联用技术分析了国产威士忌生产各阶段酒体挥发成分，利用主坐标分析初步确定不同阶段威士忌分类的标准，进而采用正交偏最小二乘判别分析法（Orthogonal Partial Least Squares Discrimination Analysis，OPLS-DA）建立以此标准分类的模型。结果表明:不同阶段酒样在挥发成分的含量上有显著差异（α=0.05），以是否浸泡为分类标准建立的OPLS-DA模型能将不同阶段威士忌酒样品明确分类。浸泡前后的关键差异化合物共有17种，其中11种成分（3-甲基丁醛、乙醛、癸酸乙酯、苯酚、糠醛、月桂酸乙酯、乙酸-2-苯乙酯、甲酸乙酯、乙酸、丁醛、十七烷）是由橡木引入到的酒体中的，除乙酸、丁醛、十七烷外，其余8种均对威士忌香气有贡献作用，橡木的引入会使得二甲硫醚、呋喃、己酸乙酯、丁醇、2-甲基-1-丙醇和正丙醇减少。说明浸泡阶段是国产威士忌挥发性风味成分形成的关键阶段。     

Flavour release from polysaccharide gels: different approaches for the determination of kinetic parameters

Two different approaches were developed to quantify aroma release: static headspace syringe injection analysis at different times, and dynamic headspace analysis with trapping on Tenax® for different times. They were applied on two polysaccharide matrices in order to better understand relationships between the structure of the food matrix and flavour perception. These two approaches allowed the determination of kinetic and thermodynamic parameters. Dynamic methods better simulate flavour release in the mouth, but only static measurements allow a determination of thermodynamic and kinetic parameters with a good precision.     

MATHEMATICAL MODEL to PREDICT EFFECT of TEMPERATURE ABUSE IN MAP SYSTEMS APPLIED to PACIFIC HAKE (MERLUCCIUS AUSTRALIS)

This paper describes the development of a mathematical model to predict consequences of temperature abuse on shelf‐life of Pacific Hake packed in modified atmosphere. the model includes simultaneous heat and mass transfer phenomena coupled with a predictive shelf‐life model for packed fish. the model was solved using an explicit finite difference scheme. the simulated results are in good agreement with the experimental results. the model predicted temperature, gas concentration and relative humidity within < 0.6[°C], < 1.43% and 3%, respectively. Shelf‐life model predicts that, even if the fraction of the total storage time at an abusive temperature is small (4.3%), the reduction in shelf‐life can be significant (25%). the predicted shelf‐life without temperature abuse is consistent with literature results. Optimum MAP systems must reach pseudoequilibrium headspace gas composition which maximize the shelf‐life of food considering possible environmental temperature abuses.     

Persistence effects in flavour release from liquids in the mouth

Summary The flavour of drinks, creams and liquid‐like food consumed without chewing is an important quality factor for consumers and manufacturers alike, so reliable predictive models of flavour release from liquids in the mouth are highly desirable. In this paper we show how the breath‐by‐breath concentration of aroma in the headspace after swallowing an aliquot of liquid can be modelled using basic principles of interfacial mass transfer. This mechanistic model is used to fit the experimental data for dilute aqueous solutions of five aroma compounds consumed by trained panellists. It is shown that many aroma compounds give detectable concentrations in the exhaled breath several minutes after swallowing and after ten or more exhalations. The influence of liquid composition on this aroma persistence effect is discussed.     

Aroma encapsulation and aroma delivery by oil body suspensions derived from sunflower seeds (<Emphasis Type="Italic">Helianthus annus</Emphasis>)

Oil bodies are small discrete cell organelles that can be found within oilseeds. Oil bodies have been investigated previously as a potential technology platform for use within the food industry, offering stable, antioxidant-enriched lipid-delivery systems. In this study, the use of oil bodies as a flavour delivery agent is evaluated. Fresh aromatized oil bodies show comparable headspace flavour intensity to phospholipid-stabilized emulsions when in a static equilibrium state, and when evaluated by dynamic headspace dilution, aromatized oil bodies showed a significantly stronger potential to maintain their headspace volatile concentration, which may indicate that oil bodies would offer greater retronasal flavour delivery than current commercial systems.     

Food‐Grade Covalent Complexes and Their Application as Nutraceutical Delivery Systems: A Review

Food proteins, polysaccharides, and polyphenols are 3 major food constituents with distinctly different functional attributes. Many proteins and polysaccharides are capable of stabilizing emulsions and foams, thickening solutions, and forming gels, although they differ considerably in their abilities to provide these functional attributes. Many plant polyphenols exhibit beneficial physiological functions, such as antitumor, antioxidant, antibacterial, and antiviral properties. Proteins, polysaccharides, and polyphenols can form complexes with each other, which leads to changes in the functional and nutritional properties of the combined systems. Recently, there has been considerable interest in understanding and utilizing covalent interactions between polyphenols and biopolymers (proteins and polysaccharides). The binary or tertiary conjugates formed may be designed to have physicochemical properties and functional attributes that cannot be achieved using the individual components. This article provides a review of the formation, characterization, and utilization of conjugates prepared using proteins, polysaccharides, and polyphenols. It also discusses the relationship between the structural properties and functionality of the conjugates, and it highlights the bioavailability of bioactive compounds loaded in conjugate‐based delivery systems. In addition, it highlights the main challenges to be considered when preparing and analyzing conjugates. This article provides an improved understanding of the chemical reactions that occur between major food ingredients and how they can be utilized to develop biopolymer‐based delivery systems with enhanced functional attributes.     

Towards a multidisciplinary approach to structuring in reduced saturated fat‐based systems – a review

Although many food products are essentially emulsions, interest in the structuring of oil‐continuous emulsions (and in specific cases water‐continuous emulsions) is intense, particularly to meet the continuing challenge of reducing the degree of saturates in food systems. Consequently, it is necessary to observe the effects of structurants and to examine their impacts on current food systems. This is especially the case where novel structuring materials are used to wholly or partially replace traditional structurants. A multidisciplinary approach is discussed encompassing traditional and novel mechanisms considered able to structure within low saturated fat‐based systems and which in themselves could also have emulsification properties. The presence of interfacial compositions as in emulsions requires a crucial understanding of the interactions within these compositions for the creation of building blocks in oil or fat structuring. Where a co‐surfactant structure may be used, together with novel structurants, for example, wax esters, phytosterols, it is necessary to understand how these may influence interfacial film thickness, strength and flexibility. Understanding how to measure mechanical visco‐elastic properties of structurant interactions both in model and real time dynamic measurements will be necessary to account for diffusion, orientation and self‐assembly mechanisms. This review discusses combining traditional techniques with novel structurant technology; developing and validating dynamic measurement techniques; and investigation of real systems as opposed to purely model systems.     

Chemical composition analysis and authentication of whisky

Whisky (whiskey) is one of the most popular spirit‐based drinks made from malted or saccharified grains, which should mature for at least 3 years in wooden barrels. High popularity of products usually causes a potential risk of adulteration. Thus authenticity assessment is one of the key elements of food product marketing. Authentication of whisky is based on comparing the composition of this alcohol with other spirit drinks. The present review summarizes all information about the comparison of whisky and other alcoholic beverages, the identification of type of whisky or the assessment of its quality and finally the authentication of whisky. The article also presents the various techniques used for analyzing whisky, such as gas and liquid chromatography with different types of detectors (FID, AED, UV–Vis), electronic nose, atomic absorption spectroscopy and mass spectrometry. In some cases the application of chemometric methods is also described, namely PCA, DFA, LDA, ANOVA, SIMCA, PNN, k‐NN and CA, as well as preparation techniques such SPME or SPE. © 2014 Society of Chemical Industry     

Role of Organic Acids in Maturation of Distilled Spirits in Oak Casks

Maturation of whiskies and brandies in oak casks proceeds by reducing the perception of less desirable aromas of new distillates. During maturation, extraction of wood components increases the solubility of distillate compounds which reduces their headspace concentration above the matured spirit. The origins of this interaction are changes in aggregation of ethanol due to increases in contents of organic acids. During wood maturation organic acid concentrations in spirits increase as a result of extraction from cask wood, oxidation of ethanol and evaporation of ethanol and water. The effect of such changes was simulated using a model whisky ester in aqueous solutions of ethanol with acetic acid, oak wood extracts and acid fractions from new and matured Scotch malt distillates.     

Comparison of the characterisation of the fruit‐like aroma of Teucrium flavum L. subsp flavum by hydrodistillation and solid‐phase micro‐extraction

BACKGROUND: Teucrium species (Lamiaceae) are interesting for the food industry since many of them are used in the preparation of flavoured wines and beers, herbal teas, bitters and liqueurs. On this basis, the analysis of the aroma components of Teucrium flavum L. subsp. flavum growing in central Italy was carried out by means of both hydrodistillation (HD) and headspace solid‐phase micro‐extraction (HS‐SPME), coupled with GC/FID and GC/MS. RESULTS: A total of 102 components were identified in the essential oils, representing 99.0‐99.3% of the total oils. Sesquiterpenes hydrocarbons constituted the major fraction (48.5–49.4%), with the apple‐like flavour (Z,E)‐α‐farnesene being the major component. HS‐SPME allowed the analysis of the volatiles not only emitted by specific plant parts, but also by different parts within a single flower: flower calyx afforded the highest contribution, in terms of volatiles, to the aroma of the plant. CONCLUSION: The chemical profile of the volatile fraction obtained by HD and HS‐SPME, demonstrated the plant fruit‐like aroma, confirming the usefulness for flavouring wines, bitters and other kind of beverages, and also suggested other applications, as aroma and taste enhancer in food processing. In particular, SPME resulted in a very useful technique, which permits a choice between the part of the plant which has the highest concentration of a specific fragrance, and therefore establishes the best way of sampling during industrial applications of aromatic plants. Copyright © 2009 Society of Chemical Industry     

Ability of physico‐chemical measure‐ments to discriminate rabbit meat from three different productive processes

BACKGROUND: To fulfil consumers' requirements for food traceability, it is necessary to have effective tools to differentiate food products according to their origin. The aim of the study was to identify a limited number of physico‐chemical measurements that could differentiate rabbit meat from three different rearing systems: standard production system or a high quality norm system or a very low growth breeding system. RESULTS: The stepwise linear discriminant analysis (LDA) provided 14 physico‐chemical variables, then combined into two discriminant factors. Most of them (n = 8) were related to bone traits, and especially (n = 5) to mechanical femur assessments. Mechanical characteristics of meat were also relevant in this analysis. Decision tree analysis (DTA) selected two variables only (femur stiffness, and ratio of femur weight to chilled carcass weight) to discriminate the three groups. A total of 96% and 90% of rabbits were correctly assigned to their original group according to LDA and DTA, respectively. CONCLUSION: This work demonstrated that simple physico‐chemical traits recorded in carcasses and meat were efficient to discriminate rabbits from three different rearing systems using LDA or DTA procedures. These systems could have further implications for future traceability of breeding origin. Copyright © 2007 Society of Chemical Industry     

Mechanistically Inspired Kinetic Approach to Describe Interactions During Co‐Culture Growth of Carnobacterium maltaromaticum and Listeria monocytogenes

Lactic acid bacteria and Listeria monocytogenes are psychotropic organisms that can grow and compete in food such as lightly preserved fishery products. Predictive microbiology is nowadays one of the leading tools to assess the behavior of bacteria in food and to predict food spoilage. Mathematical models can be used to predict the growth, inactivation or growth probability of bacteria. Currently, the efforts in microbial modeling are oriented towards extrapolation of results beyond experiments in order to predict the growth of interacting microorganisms and develop new food preservation processes. In the present work, a model combining both heterogeneous population and quasi‐chemical approaches to describe the different phases of the bacterial growth curve is presented. The model was applied to both monoculture and co‐culture cases of lactic acid bacteria, Carnobacterium maltaromaticum H‐17, and two Listeria monocytogenes strains in a raw fish extract. It is a highlight that our model includes novel inhibition reactions due to the accumulation of metabolites, and a general equation to take into account the effect of chemical compounds during the lag or physiological adaptation phase of the cells. Our results show that the proposed model can accurately describe the experimental data when the curve shape is a sigmoid, and when it presents a maximum. Besides, the parameters have biological interpretability since the model is mechanistically inspired.     

Chromatographic Methods for the Determination of Polyfunctional Amines and Related Compounds Used as Monomers and Additives in Food Packaging Materials: A State‐of‐the‐Art Review

Abstract: Polyfunctional amines are a group of substances commonly used as additives or monomers in food‐contact materials. These substances can migrate into foodstuffs and, consequently, may be potentially dangerous for human health. Due to their different chemical structures and physicochemical properties there does not exist a standard method to analyze polyfunctional amines. This review aims to provide an update on the chromatographic methods used for the determination of polyfunctional amines that are commonly used in the manufacture of food packaging materials. Detailed information regarding chromatographic conditions (mobile phases, chromatographic columns, detection systems, and so on) is provided. Moreover, chemical structures and physicochemical properties of the substances studied are also presented.     

Process engineering for bioflavour production with metabolically active yeasts – a mini‐review

Flavours are biologically active molecules of large commercial interest in the food, cosmetics, detergent and pharmaceutical industries. The production of flavours can take place by either extraction from plant materials, chemical synthesis, biological conversion of precursor molecules or de novo biosynthesis. The latter alternatives are gaining importance through the rapidly growing fields of systems biology and metabolic engineering, giving efficient production hosts for the so‐called 'bioflavours', which are natural flavour and/or fragrance compounds obtained with cell factories or enzymatic systems. Yeasts are potential production hosts for bioflavours. In this mini‐review, we give an overview of bioflavour production in yeasts from the process‐engineering perspective. Two specific examples, production of 2‐phenylethanol and vanillin, are used to illustrate the process challenges and strategies used. Copyright © 2014 John Wiley & Sons, Ltd.     

Influence of saliva on temporal volatile flavour release from red bell peppers determined by proton transfer reaction-mass spectrometry

The effect of saliva on temporal volatile flavour release from rehydrated red bell peppers was evaluated. The addition of 40% artificial saliva (w/w) was studied using a model mouth combined with proton transfer reaction-mass spectrometry. Saliva reduced the maximum headspace concentration during temporal release of 2-methylpropanal, 2/3-methylbutanal and hexanal by 42% on average. This was attributed to an effect of saliva on both the thermodynamic and kinetic component of flavour release, as saliva resulted in an average decrease of 25% for these compounds in equilibrium headspace analysis. A preliminary comparison of model mouth and in-nose analysis showed that the model mouth mimicked temporal release under mouth conditions quite well.     

High‐Amylose Starches to Bridge the “Fiber Gap”: Development,Structure, and Nutritional Functionality

Although high‐amylose starches are not a recent innovation, their popularity in recent years has been increasing due to their unique functional properties and enhanced nutritional values in food applications. While high‐amylose maize, barley, and potato are commercially available, high‐amylose variants of other main crops such as wheat and rice have once been developed more recently and will be available commercially in the near future. This review summarizes the development, structure, and nutritional functionality of high‐amylose starches developed and reported so far. The range of biotechnological strategies utilized are reviewed, as are the consequent effects on structural properties at different length scales, as well as sensory aspects of foods containing high‐amylose starch (HAS). This review identifies the molecular and microstructural features contributing to digestive enzyme resistance not only in native HAS but also in forms of relevance to food processing. During heat treatment, HAS tends to retain or form dense molecular structures that resist amylase degradation through the retention of the granular structure as well as helices (type‐2 resistant starch [RS]), reassociation of glucan chains (type‐3 RS), and formation of lipid–amylose complexes (type‐5 RS). The review also identifies opportunities for food manufacturers and consumers to incorporate HAS in food products and diets for better nutritional outcomes.     

Use of Volatiles as Indicators of Lipid Oxidation in Muscle Foods

Lipid oxidation has long been recognized as a leading cause of quality deterioration in muscle foods and is often the decisive factor in determining food product storage life. Lipid oxidation generates a number of products, including volatile compounds, which are the major contributors to the development of rancid off‐flavors and odors. Over the years, methodologies have been developed to quantify lipid oxidation products in muscle foods. This article reviews the analytical methods that have been used to quantify volatile compounds as indicators of lipid oxidation in muscle foods. The sampling methodologies of distillation/solvent extraction and headspace analysis, and isolation methods associated with gas chromatographic (GC) and high‐performance liquid chromatography (HPLC) analyses are discussed. Within gas chromatographic methodologies, headspace (HS) sampling (static HS, dynamic purge‐and‐trap HS techniques, and solid‐phase microextraction [SPME]) are addressed.