Aroma-active secondary oxidation products of butter

Butter contains vitamins, minerals and unsaturated lipids, such as polyunsaturated fatty acids (PUFA) and conjugated linoleic acids (CLAs). However the oxidative stability and consequently the shelf-life of milk products are inversely correlated with their PUFA and CLA content. The objective of this study is the evaluation of the oxidative stability and sensory quality of PUFA/CLA-enriched butter versus conventional butter, with both types of butter being produced at ALP. For this purpose, new chemical and sensory-based methods will be developed, as well holistic complementary methods. This paper focuses on a preliminary study achieved using conventional butter, subjected to a long storage and to oxygen and light exposure, to develop a gas chromatography olfactometry (GC-O) method able to detect the aroma-active compounds originated from oxidation. This will be one of the methods used for the evaluation of the oxidative stability of PUFA/CLA-enriched butter

Chemische Zusammensetzung und sensorisches Profil von UFA/CLA angereicherter Butter im Vergleich zu konventioneller Butter

In the last years, there has been a growing demand by consumers for foods combining an increased nutritional value and benefits on human health. Butter enriched in unsaturated fatty acids/conjugated linoleic acids (UFA/CLA) could become a food with added value for its increased content in essential fatty acids, in vitamins and CLA, which has been reported to show potential anticarcinogenic and cholesterol lowering effects. The aim of the present study was to evaluate the chemical composition and the sensory and odour profiles of UFA/CLA enriched butter in comparison to conventional butter. Their fatty acid composition, vitamin and metal ion contents were determined in both kinds of butter. Descriptive sensory analysis and gas chromatography-mass spectrometry coupled to olfactometry (GC/MS/O) were applied to UFA/CLA enriched and conventional butter. The UFA/CLA enriched butter contained significantly higher CLA than conventional butter. α-Tocopherol and iron contents were also significantly higher in UFA/CLA enriched butter. The sensory profile of the UFA/CLA enriched butter showed a less intense creamy odour and cooked milk aroma than conventional butter. UFA/CLA enriched butter revealed a better spreadability. The olfactometric results of the fresh butter samples indicated that the enriched butter had more intense green, sulphury and fruity notes, due to (Z)-3-hexenol, dimethyl disulphide, 2-phenylethyl acetate and δ-decalactone, respectively, compared to conventional butter

Assessment of processing technologies which may improve the nutritional composition of dairy products – Overview of progress

Among consumers there is a growing demand for food products with a natural nutritional-physiological advantage over comparable conventional products. As part of an EU funded project, ALP is examining the possible impact of processing on nutritionally valuable milk components, using the example of conjugated linoleic acids (CLA). The extent to which processing influences the CLA content of the end product was determined by literature research and own investigations of organic and conventional butter. Furthermore, new chemical, sensory-based and bio crystallization methods were evaluated by ALP and the University of Kassel to determine the oxidation stability of butter. In a further step the storage stability of CLA enriched and conventional butter was examined and the different methods will be compared. As a third objective a process for low-input CLA enrichment of milk fat (with a focus on alpine butter) has been developed. Since the process selected for the work is a physical enrichment process, it is accepted by international organic farming and food groups. Among the many benefits ascribed to CLA, it is believed to be an effective agent against cancer. The demand for foods with properties that promote human health is growing. The dairy industry has the opportunity to meet this demand by developing new dairy products with a nutritional-physiological function for the functional food market

Formation of alanine, α-aminobutyrate, acetate, and 2-butanol during cheese ripening by Pediococcus acidilactici FAM18098

There is limited information about the contribution of Pediococcus acidilactici, a nonstarter lactic acid bacteria, to cheese ripening and flavour development. Model Tilsit-type and Gruyère-type cheeses were produced using P. acidilactici FAM18098 as an adjunct. The adjunct did not influence the cheese manufacturing processes. The pediococcal log counts ranged from 7.0 to 8.0 cfu g-1 after 90 and 120 days of ripening. P. acidilactici produced ornithine, a result of arginine metabolism by the arginine deiminase pathway, and a-aminobutyrate and alanine while simultaneously metabolising serine and threonine. The analysis of the volatile compounds in the cheeses showed that higher acetate, 2-butanone, and 2-butanol levels and lower diacetyl levels were present in the cheeses produced with P. acidilactici than in the control cheeses. The study illustrates that P. acidilactici can influence amino acid metabolism in cheese; further, ornithine, a-aminobutyrate, and acetate can serve as indicators for the presence of this species. © 2019 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Hydrophilic interaction liquid chromatography (HILIC)—a powerful separation technique

Hydrophilic interaction liquid chromatography (HILIC) provides an alternative approach to effectively separate small polar compounds on polar stationary phases. The purpose of this work was to review the options for the characterization of HILIC stationary phases and their applications for separations of polar compounds in complex matrices. The characteristics of the hydrophilic stationary phase may affect and in some cases limit the choices of mobile phase composition, ion strength or buffer pH value available, since mechanisms other than hydrophilic partitioning could potentially occur. Enhancing our understanding of retention behavior in HILIC increases the scope of possible applications of liquid chromatography. One interesting option may also be to use HILIC in orthogonal and/or two-dimensional separations. Bioapplications of HILIC systems are also presented

Hydrophilic di- and tripeptides are not a precondition for savoury flavour in mature Cheddar cheese

In the literature hydrophilic glutamyl di- and tripeptides have been described to induce an umami or savoury taste. In this study, HILIC-ESI-MS was applied for analysis of low-molecular-weight peptides in the ultra-filtrated (cut-off 10 kg$\cdot$mol$^{-1})$ water-soluble extract of two mature Cheddar cheeses, selected because of their pronounced savoury flavour. A reference mixture of amino acids and di- and tripeptides was successfully separated by HILIC using ammonium acetate buffer (0.50 g$\cdot$L$^{-1}$, pH 5.5) as the mobile phase. Unambiguous identification of the compounds was based on retention time and characteristic fragmentation patterns in MS/MS and MS$^{3}$. However, no low-molecular-weight glutamyl peptides were identified in the extracts of the mature Cheddar cheeses. It was concluded that hydrophilic glutamyl di-and tripeptides are not a precondition for savoury flavour in mature Cheddar cheese.Dans la littérature, les di- et tripeptides à glutamine ont été décrits comme induisant un goût umami ou savoureux. Dans cette étude, nous avons analysé par chromatographie liquide à interaction hydrophile (HILIC) couplée à la spectrométrie de masse (ESI-MS) les peptides de faible poids moléculaire présents dans l'ultrafiltrat (seuil de coupure 10 kg$\cdot$mol$^{-1}$) d'extrait aqueux de deux Cheddar affinés, sélectionnés en raison de leur flaveur savoureuse prononcée. Un mélange de référence d'acides aminés et de di- et tripeptides a été séparé avec succès par HILIC en utilisant un tampon d'acétate d'ammonium (0,50 g$\cdot$L$^{-1}$, pH 5,5) comme phase mobile. L'identification des composés a été réalisée sans ambigüité d'après leurs temps de rétention et leurs profils de fragmentation caractéristiques en MS/MS et MS$^{3}$. Cependant, aucun peptide à glutamine de faible poids moléculaire n'a été identifié dans les extraits de Cheddar affiné. Nous en avons conclu que les di- et tripeptides à glutamine hydrophiles ne pré-conditionnent pas la flaveur savoureuse du Cheddar affiné

Determination of storage stability of butter enriched with unsaturated fatty acids/conjugated linoleic acids (UFA/CLA) using instrumental and sensory methods

The oxidative stability of butter enriched with unsaturated fatty acids and conjugated linoleic acids (UFA/CLA butter) was evaluated by chemical, sensory and microbiological analyses during 8 weeks of storage at 6 °C and compared with that of conventional butter. The odour-active compounds were analyzed by gas chromatography–mass spectrometry combined with olfactometry, using solid phase microextraction. Olfactometric analysis showed that both, fresh UFA/CLA butter and fresh conventional butter had similar aroma profiles. After 6–8 weeks of storage, UFA/CLA butter showed stronger fatty (butanoic and 3-methyl butanoic acid), metallic [(E,E)-2,4-nonadienal], green [(E)-2-hexenol] and creamy (2-pentanone) notes compared with the conventional samples. A sensory panel described the two fresh butter types as having a similar sensory profile, except for a stronger creamy aroma, a less intense cooked milk aroma and a significantly higher spreadability of the UFA/CLA butters. Sensory descriptive analysis showed also that both butter types aged in a very similar way, with an increase in rancid and oxidized notes. (c) 2008 Elsevier Ltd. All rights reserved

Terpenoids and benzenoids in La Serena cheese made at different seasons of the year with a Cynara cardunculus extract as coagulant

The objective was to determine the influence of the season of manufacture and the ripening time on the volatile terpenoids and benzenoids of La Serena cheese made in summer, winter and spring, using a plant coagulant. Ewes were fed with formulated feed in summer, grazing on natural pastures in winter and spring. Most terpenoids and benzenoids present in cheese were observed in the formulated feed (mainly terpenes), and in the Cynara cardunculus extract (mainly benzenoids). The enantiomeric α(+){plus 45 degree rule}α(-)-pinene ratio changed during ripening. γ-Curcumene, α-humulene, ethyl benzene and propyl benzene and all xylene isomers decreased, while α-terpineol, verbenone, benzyl alcohol, 2-phenyl-ethanol, benzoic acid methyl ester, and the phenolic compounds increased significantly during ripening. Safranal, geranyl acetone, γ-curcumene and α-curcumene were more abundant in spring than in winter cheeses. Alkyl benzenes and other benzenoids were significantly more abundant in summer than in winter or spring cheeses. © 2007 Elsevier Ltd. All rights reserved