Changes during the extrusion of semolina in mixture with sugars

Farouk, Amr; Pudil, F.; Janda, V.; Pokorný, Jan

doi:10.17221/6570-cjfs

Cited by 4 publications

(1 citation statement)

References 18 publications

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“…Ketones were also identified among MRPs studied by Cui K. et al [18]. Mansour et al [21], in an investigation into the effects of glucose, fructose, and sucrose on the flavor of extruded wheat semolina, likewise detected ketones.…”

Section: Introductionmentioning

confidence: 85%

The Role of Saccharomyces cerevisiae Yeast and Lactic Acid Bacteria in the Formation of 2-Propanol from Acetone during Fermentation of Rye Mashes Obtained Using Thermal-Pressure Method of Starch Liberation

et al. 2019

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This study set out to assess the acetone content in rye sweet mashes prepared using the thermal-pressure method of starch liberation, and to investigate the formation of 2-propanol during the fermentation process. In the first set of experiments, we evaluated the correlation between the color and the content of acetone and furfural in industrially produced sweet mashes (n = 37). The L * value was negatively correlated with the content of both acetone and furfural, while chromatic parameters a * and b * and the yellowness index (YI) had strong positive correlations with acetone (r > 0.9) and furfural (r > 0.8 for a * and r > 0.9 for b * and YI). In the second set of experiments, we assessed the concentration of acetone and 2-propanol in distillery rye mashes, fermented by S. cerevisiae yeast and lactic acid bacteria. The influence of fermentation temperature on the formation of 2-propanol was also evaluated. The presence of 2-propanol in the post-fermentation media was confirmed, while a decrease in acetone content was observed. Fermentation temperature (27 °C or 35 °C) was found to have a significant effect on the concentration of 2-propanol in trials inoculated with lactic bacteria. The content of 2-propanol was more than 11 times higher in trials fermented at the higher temperature. In the case of yeast-fermented mashes, the temperature did not affect 2-propanol content. The acetone in the sweet mash was assumed to be a precursor of 2-propanol, which was found in the fermented mashes.

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Section: Introductionmentioning

confidence: 85%

The Role of Saccharomyces cerevisiae Yeast and Lactic Acid Bacteria in the Formation of 2-Propanol from Acetone during Fermentation of Rye Mashes Obtained Using Thermal-Pressure Method of Starch Liberation

et al. 2019

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Heyns Rearrangement

2010

Comprehensive Organic Name Reactions and Reagents

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The rapid rearrangement of α‐hydroxy imines (including α‐hydroxy Schiff bases) into stable α‐amino carbonyl compounds (i.e., α‐ketoamines) under nonreducing conditions and is generally referred to as the Heyns rearrangement. The formation of imines or Schiff base derivatives is thermodynamically reversible, whereas the α‐hydroxyl group facilitates the Heyns rearrangement, leading to the formation of stable α‐ketoamines. The formation of Schiff base is considered as the rate‐limiting step for this reaction. This reaction is related to the Amadori rearrangement and Maillard reaction and lead to the formation of several important chemicals. This rearrangement has proven valuable in food chemistry.

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Effect of defatted soybean flour on the flavour of extruded mixtures with wheat flour

Pokorný¹,

Farouk²,

Pudil³

et al. 2002

Czech J. Food Sci.

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Mixtures of wheat semolina, 5% glucose and 0-30% defatted soybean flour were used for the preparation of extruded samples using a pilot plant single screw extruder, maximum temperature being 140°C. The browning reactions were only moderate, the intensities of the trichromatic a* coordinate increased, and some changes were observed in chroma and the odour difference ∆E*. The sensory acceptability improved by increasing the content of soybean flour, the odour intensity increased, and some changes were observed in the sensory profile. Volatile substances were isolated using a SPME procedure, and the volatiles were separated using a Fisons GLC 8000 apparatus equipped with a mass spectrometer. Among the flavour active volatiles, pyrazines were the most prominent class of compounds, especially methyl and ethyl substituted derivatives. Pyrrole and furan substituted pyrazines were found only in small amounts because of the low extrusion temperature. Other furan and pyrrole derivatives had a lesser effect on flavour because of their relatively low amounts. Aldehydes, fatty acids, ketones, and other aliphatic derivatives contributed only a little to the resulting flavour. Compared to the mixtures of semolina and glucose only, the additions of defatted soybean flour moderately increased the number of substituted pyrazines detected in the extruded mixtures but increased substantially the pyrazine fraction in the total peak area. Among furan derivatives, 2-furancarboxaldehyde, 2-furanmethanol and 5-methyl-2-furyl alcohol belonged to the most prominent derivatives. Among other compounds, acetic acid, butyrolactone and maltol should be mentioned.Keywords: extrusion; flavour; pyrazines; soybean flour; wheat flour 230 Vol. 20, Czech J. Food Sci.pyrroles, and pyrazines was enhanced by the addition of reducing sugars and by the addition of amino acids. The results were previously published in greater detail (FA-ROUK MANSOUR et al. 2000MANSOUR et al. , 2001. Both reducing sugars and free amino acids are efficient precursors of Maillard reactions. Furan derivatives and maltol originate from sugar degradation products during extrusion cooking (RIHA & HO 1996) but pyrazines are the main sensory active products of Maillard reactions (YOO & HO 1997). Their content is higher in rye bread than in wheat bread (SCHIEBERLE & GROSCH 1987). Pyrazines, which possess very strong roasted bread crust and even burnt flavour notes, were isolated from bread (ROTHE 1974;RIHA & HO 1996;SCHIEBERLE & GROSCH 1984; OSNA-BRUGGE 1989). BALTES and BOCHMANN (1987) isolated many (more than 200) pyrazines from heated model mixtures of amino acids and sucrose as obtained at a temperature corresponding to that of coffee roasting.Similar processes occur during the extrusion cooking of cereal products (LUNDGREN et al. 1991/92). Under mild extrusion conditions used in our experiments, the production of volatile heterocyclic substances was much less intensive than in the course of model experiments or traditional baking. The number of oxygen and nitrogen cont...

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Changes during the extrusion of semolina in mixture with sugars

Cited by 4 publications

References 18 publications

The Role of Saccharomyces cerevisiae Yeast and Lactic Acid Bacteria in the Formation of 2-Propanol from Acetone during Fermentation of Rye Mashes Obtained Using Thermal-Pressure Method of Starch Liberation

The Role of Saccharomyces cerevisiae Yeast and Lactic Acid Bacteria in the Formation of 2-Propanol from Acetone during Fermentation of Rye Mashes Obtained Using Thermal-Pressure Method of Starch Liberation

Heyns Rearrangement

Effect of defatted soybean flour on the flavour of extruded mixtures with wheat flour

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