Effect of pH and Temperature on the Formation of Volatile Compounds in Cysteine/Reducing Sugar/Starch Mixtures during Extrusion Cooking

Abstract

Mixtures of cysteine, reducing sugar (xylose or glucose), and starch were extrusion cooked using feed pH values of 5.5, 6.5, and 7.5 and target die temperatures of 120, 150, and 180 degrees C. Volatile compounds were isolated by headspace trapping onto Tenax and analyzed by gas chromatography--mass spectrometry. Eighty and 38 compounds, respectively, were identified from extrudates prepared using glucose and xylose. Amounts of most compounds increased with temperature and pH. Aliphatic sulfur compounds, thiophenes, pyrazines, and thiazoles were the most abundant chemical classes for the glucose samples, whereas for xylose extrudates highest levels were obtained for non-sulfur-containing furans, thiophenes, sulfur-containing furans, and pyrazines. 2-Furanmethanethiol and 2-methyl-3-furanthiol were present in extrudates prepared using both sugars, but levels were higher in xylose samples. The profiles of reaction products were different from those obtained from aqueous or reduced-moisture systems based on cysteine and either glucose or ribose.

Volatile compounds in meat and meat products

“…Sugars form many volatile compounds in reactions with amino acids, e.g. glucose forms pyrazines with lysine (Ames et al, 2001), and ribose forms many key sulfur compounds with cysteine, like e.g. : 2-furanmethanethiol, 3-mercapto-2-pentanone, 2-methyl-3-furanthiol, 3-mercapto-2-butanone, bis(2-methyl-3-furyl) disulfide, 2-acetyl-2-thiazoline, 1-mercapto-2-propanone and 3-methyl-3-thiophenethiol (Hofmann & Schieberle, 1995;Cerny & Davidek, 2003).…”

Flavor Characteristics of Hanwoo Beef in Comparison with Other Korean Foods

“…They are the predominant flavor component of beef as formation of the Maillard products such as pyrazines and their interaction products are limited (Bredie et al, 1998; Ames et al, 2001). The present study also revealed that aldehydes were the most predominant among the detected flavor compounds in both numbers and amounts in cooked Hanwoo beef.…”

“…The types and concentrations of free amino acids/peptides, fatty acids, reducing sugars in foods influence flavor traits as a consequence of their participation in the reactions, oxidation and degradation processes during heating to form flavor components (Macleod, 1994; Mottram, 1994; Elmore et al, 2002). In addition, moisture content, pH, and heating conditions affect types and concentrations of volatile flavor components (Shi and Ho, 1994; Madruga and Mottram, 1995; Ames et al, 2001). …”

Sense of smell and volatile aroma compounds and their role in the evaluation of the quality of products of animal origin – a review

“…The content of volatile compounds is also affected by pH value and the method of preparation and thermal processing (Meynier and Mottram, 1995;Mottram, 1998;Ames et al, 2001).…”

“…It should be noted that the differences between various types of meat are not necessarily always the same, since the composition of volatile compounds is also affected by the degree of meat maturity (Campbell et al, 2001, Stetzer et al, 2008, as well as a number of other genetic and non-genetic factors (Tai and Ho, 1998;Ames et al, 2001;Campbell et al, 2001;Insausti et al, 2005;Calkins and Hodgen, 2007;Cerny and Briffod, 2007). Moreover, the importance of reproducibility of chromatographic analysis, including column and SPME fibre wear, for the reliability of results should be emphasised (own observations).…”