Identification of aroma-active volatiles in banana Terra spirit using multidimensional gas chromatography with simultaneous mass spectrometry and olfactometry detection.

Fruit spirits have been produced and consumed throughout the world for centuries. However, the aroma composition of banana spirits is still poorly characterised. We have investigated the aroma-impact compounds of the banana Terra spirit for the first time, using multidimensional gas chromatography (MDGC and GC × GC) in a multi-hyphenated system - i.e., coupled to flame ionisation detection (FID), mass spectrometry (MS), and olfactometry (O). Solid-phase microextraction (SPME) was used to isolate the headspace aroma compounds of the banana spirit. The detection frequency (DF) technique was applied and aroma regions, detected in the first column separation at >60% Nasal Impact Frequency (NIF), were screened as target potent odour regions in the sample. Using a polar/non-polar phase column set, the potent odour regions were further subjected to MDGC separation with simultaneous O and MS detection for correlation of the aroma perception with MS data for individual resolved aroma-impact compounds. GC-O analysis enabled 18 aroma-impact regions to be located as providing volatiles of interest for further study; for example, those comprising perceptions of flower, whisky, green, amongst others. Compounds were tentatively identified through MS data matching and retention indices in both first and second dimensions. The principal volatile compounds identified in this work, which are responsible for the characteristic aroma of the banana spirit, are 3-methylbutan-1-ol, 3-methylbutan-1-ol acetate, 2-phenylethyl acetate and phenylethyl alcohol. This is the first such study to reveal the major aroma compounds that contribute to banana spirit aroma.

Identification of odour-active compounds of pasteurised orange juice using multidimensional gas chromatography techniques.

Odour-active compounds present in pasteurised orange juice were identified by gas chromatography-olfactometry (GC-O) employing heart-cut multidimensional GC techniques with olfactometry (O) and mass spectrometry (H/C MDGC-O/MS) and comprehensive two-dimensional gas chromatography-accurate mass time-of-flight MS (GC×GC-accTOFMS). Headspace solid phase microextraction sampling proved to be qualitatively adequate for the analysis of pasteurised orange juice. The GC-O approach distinguished 13 potent odour regions (detection frequency≥3) in the orange juice extract, in which 7 regions were then subjected to detailed identification of the compounds that contribute to the odour, by using higher resolution H/C MDGC-O/MS. This analysis permitted the odour-active peaks to be better resolved on the 2D column, with removal from background matrix, for the seven regions. GC×GC-FID and GC×GC-accTOFMS reveal the overall complexity of the volatile compounds in the product and assisted in assignment of the isolated peaks of the odour-active compounds, confirming the identification in a number of cases. Four aldehydes (hexanal, heptanal, octanal, citral), 2 esters (ethyl butanoate, methyl hexanoate), and 4 monoterpenes (α-pinene, D-limonene, linalool, α-terpineol) were confirmed in accordance with olfactometry assessment in the processed juice. This multi-assessment instrument approach of GC-O, GC×GC, and H/C MDGC provided an effective insight into the processed orange juice aroma.

Emprego da hidrólise enzimática utilizando subtilisina para elevar o valor nutricional do soro de leite / Use of enzymatic hydrolysis using subtilisin for increasing the nutritional value of whey

With the aim of increasing the nutritional value of whey, a subtilisin was used for hydrolysing its proteins and obtaining high di-tripeptide and free amino acid contents, besides small amounts of large peptides. The whey protein concentrate was used as raw material and different hydrolytic conditions were tested such as reaction time (5, 10 and 15h), enzyme:substrate ratio (1:100, 2:100 and 4:100) and raw material concentration (10% and 15%). The peptide profi les were initially characterized using a fractionation method by a size-exclusion-HPLC followed by a rapid Corrected Fraction Area method for quantifying the peptides. The action of subtilisin showed varied effects depending on the hydrolysis parameters used. The best peptide profi le was obtained using a raw material concentration of 10%, an enzyme:substrate ratio of 4:100, after 5h reaction, reaching 13.34% ofdi-tripeptides, 45.56% of free amino acids and just 12.28% of large peptides.

Con el propósito de mejorar el valor nutricional del suero lácteo, fue empleada una subtilisina para hidrolizar sus proteínas y obtener un alto contenido de di-tri péptidos, aminoácidos libres con reducción del tenor de grandes péptidos.La materia prima fue el concentrado proteico del suero lácteo y diferentes condiciones de hidrólisis fueron probadas: tiempo de hidrólisis(5, 10 y 15h), la relación enzima: substrato (1:100, 2:100 y 4:100) y la concentración de la materia prima (10% y 15%). Se caracterizó elperfi l peptídico por medio de fraccionamiento de los hidrolizados utilizando cromatografía líquida de alta efi ciencia de exclusión moleculary la cuantifi cación de los componentes de las fracciones cromatográfi cas fue realizada por el método rápido del área corregida de la fracción. Para los parámetros estudiados, se observaronefectos variados de la subtilisina en la obtención de los hidrolizados, y el mejor perfi l peptídico fue encontrado cuando se utilizó la concentración de materia prima de 10%, relación enzima: substrato de 4:100 y 5 horas de reacción. Estas condiciones dieron origen a un hidrolizado compuesto de 13,34% de di-tripeptídeos, 45,56%de aminoácidos libres y sólo 12,28% de grandes péptidos.

Com o intuito de elevar o valor nutricional do soro de leite, foi empregada uma subtilisinapara hidrolisar suas proteínas e obter alto teor de di-tripeptídios, e de aminoácidos livres, alémde pequena quantidade de grandes peptídios. A matéria-prima utilizada foi o concentrado proteico do soro de leite e diferentes condições hidrolíticas foram testadas, tais como o tempo dereação (5, 10 e 15h), a relação enzima:substrato (1:100, 2:100 e 4:100) e a concentração damatéria-prima (10% e 15%). Caracterizou-se o perfil peptídico pelo fracionamento dos hidrolisados por cromatografia líquida de alta eficiência de exclusão molecular e, para a quantificação dos componentes das frações cromatográficas, empregou-se o método rápido da Área Corrigida da Fração. Para os parâmetros estudados, observaram-se efeitos variados da subtilisina na obtenção dos hidrolisados, sendo que o melhor perfil peptídico foi encontrado ao se empregar a concentração da matéria-primade 10%, relação enzima:substrato de 4:100, após 5 h de reação, tendo obtido 13,34% de ditripeptídeos, 45,56% de aminoácidos livres e, apenas, 12,28% de grandes peptídios.