Effect of processing and flavour fine-tuning techniques on the volatile flavour constituents of pseudocereals and some minor cereals

Different processing techniques have been used for many centuries to increase the amount of bioactive components and the subsequent fine-tuning of flavour compounds of pseudocereals and the lesser cereals. After an introduction into the different processing methods that leads to the formation of characteristic flavours in pseudocereal and the lesser cereal products, results of studies aimed at indicating the influence of biotechnical processes (e.g. germination and malting), sourdough/sourslurry fermentation and thermal processing on the final aroma of pseudocereal and the lesser cereal products are summarized in this review. Also, the characteristic flavour compounds in both the native and the products of the pseudocereals and the lesser cereals coupled with their stability are highlighted with respect to their contribution to the overall aroma

Investigation of the retronasal perception of palm wine (Elaeis Guineensis) aroma by application of sensory analysis and exhaled odorant measurement (exom).

The headspace profile of palm wine was evaluated by time-resolved sensory analysis showing significant changes of the diverse odour attributes with time after swallowing. Fruity and citrusy were the most intense aroma qualities perceived upon sample introduction into the mouth, while swallowing of the palm wine elicited a more acidic impression followed by citrusy and fruity nuances respectively. After swallowing, panelists described an increase in the nutty and popcorn-like aroma impressions. Based on these sensory observations, the retronasal aroma perception of palm wine was investigated by application of the modified Exhaled Odorant Measurement (EXOM)-approach. In EXOM analysis, odorants that are exhaled through the nose during food consumption and swallowing are collected and analysed by high resolution gas chromatography-olfactometry and mass spectrometry, respectively. EXOM results revealed an initial 24 odor-active compounds in the \'swallow\' breath with 23 of these odorants being identified on the basis of their odor qualities and intensities, as well as chromatographic and mass spectral data. Only 14 compounds were detectable in the exhaled breath 20 s after swallowing the palm wine and 11 of these were subsequently identified. Generally, the identified odorants belonged to very diverse odorant substance classes such as heteroaromatic compounds, esters, alcohols, carbonyl and thio compounds and many more. Among these, higher persistence intervals in the exhalation breath were obtained for the buttery smelling compounds butan-2,3-dione and 3-hydroxy-butan-2-one (acetoine), 3-isobutyl 2- methoxypyrazine with bell pepper-like aroma impression, the malty smelling 2- and 3-methylbutanols, and the coconut-like smelling γ-dodecalactone. The popcorn-like smelling 2-acetyl 1-pyrroline, the fresh flowery linalool and two unknown compounds with citrusy and buttery aroma impressions were only detectable at 20 s after swallowing. Dynamic changes were also observed in retronasal sensory evaluations that were attributed to specific palm wine odorants. Accordingly, both sensory and analytical data on retronasal aroma perception of palm wine monitored the dynamic flavour changes during palm wine consumption. Keywords: Retronasal, EXOM, swallow breath, 2-acetyl 1-pyrroline African Journal of Food, Agriculture, Nutrition and Development Vol. 9 (2) 2009: pp. 793-81

Influence of starter culture on the physicochemical properties of rice bran sourdough and physical quality of sourdough bread

The effect of mixed strain culture of lactic acid bacteria (LAB) and Yeast, and yeast or L. brevis, L. plantarum, or L. sanfranciscencison the physicochemical properties (pH, TTA, organic acid, ethanol, and sugar content) of rice bran sourdough was investigated. Starter culture with optimum physicochemical properties was used to ferment rice and wheat bran for sourdough production. Rice and wheat bran sourdough and non-fermented rice and wheat bran were mixed with wheat flour at 10% substitution level for bread production. Results showed that rice bran fermented with L. plantarumhad the best physicochemical properties compared to rice bran sourdough produced by other LAB or mixed culture. The specific volume of bread sample made with rice bran sourdough (4.65 cm3/g) was higher than that of the bread samples made from wheat bran sourdough (4.32 cm3/g) and non-fermented bran (3.74 –4.24 cm3/g), but not significantly different from the control (100% wheat) bread (4.85 cm3/g). The crumb colour of the rice bran and rice bran sourdough substituted bread was lighter than that of the other bread samples. Crust colour of all the bread samples was not significantly different (p > 0.05). At the end of 6 days storage period, bread samples from control and wheat bran sourdough were firmer than that from rice bran sourdough, however, crumb firmness values were highest in non-fermented bran substituted bread. Sensory analysis result revealed that rice bran sourdough bread was more acceptable than wheat bran sourdough bread, and non-fermented rice and wheat bran substituted bread

Microbial and Sensory Quality of Freshly Processed and Reconstituted “Kununzaki”- A Nigerian Millet Based Beverage

The microbial and sensory qualities of freshly processed and reconstituted Kununzaki beverages prepared from steeped millet grains were carried out. The samples were analysed for Aerobic plate, Fungi, Coliform, Staphylococcal, Salmonella and Shigella counts. The samples were also evaluated for difference and preference. The study showed that the reconstituted beverage had better microbiological quality with detectable difference between the two samples with the fresh sample being preferred. Key words: Millet grains, Kununzaki, microbial quality, sensory quality. J Food Tech in Africa (2002) 7, 65-6

Investigation of the retronasal perception of palm wine (Elaeis Guineensis) aroma by application of sensory analysis and exhaled odorant measurement (exom).

The headspace profile of palm wine was evaluated by time-resolved sensory analysis showing significant changes of the diverse odour attributes with time after swallowing. Fruity and citrusy were the most intense aroma qualities perceived upon sample introduction into the mouth, while swallowing of the palm wine elicited a more acidic impression followed by citrusy and fruity nuances respectively. After swallowing, panelists described an increase in the nutty and popcorn-like aroma impressions. Based on these sensory observations, the retronasal aroma perception of palm wine was investigated by application of the modified Exhaled Odorant Measurement (EXOM)-approach. In EXOM analysis, odorants that are exhaled through the nose during food consumption and swallowing are collected and analysed by high resolution gas chromatography-olfactometry and mass spectrometry, respectively. EXOM results revealed an initial 24 odor-active compounds in the \'swallow\' breath with 23 of these odorants being identified on the basis of their odor qualities and intensities, as well as chromatographic and mass spectral data. Only 14 compounds were detectable in the exhaled breath 20 s after swallowing the palm wine and 11 of these were subsequently identified. Generally, the identified odorants belonged to very diverse odorant substance classes such as heteroaromatic compounds, esters, alcohols, carbonyl and thio compounds and many more. Among these, higher persistence intervals in the exhalation breath were obtained for the buttery smelling compounds butan-2,3-dione and 3-hydroxy-butan-2-one (acetoine), 3-isobutyl 2- methoxypyrazine with bell pepper-like aroma impression, the malty smelling 2- and 3-methylbutanols, and the coconut-like smelling γ-dodecalactone. The popcorn-like smelling 2-acetyl 1-pyrroline, the fresh flowery linalool and two unknown compounds with citrusy and buttery aroma impressions were only detectable at 20 s after swallowing. Dynamic changes were also observed in retronasal sensory evaluations that were attributed to specific palm wine odorants. Accordingly, both sensory and analytical data on retronasal aroma perception of palm wine monitored the dynamic flavour changes during palm wine consumption. Keywords: Retronasal, EXOM, swallow breath, 2-acetyl 1-pyrroline African Journal of Food, Agriculture, Nutrition and Development Vol. 9 (2) 2009: pp. 793-81

Characterization of the key aroma compounds in three types of bagels by means of the sensomics approach

Background: To evaluate the impact of cold fermentation time on bagel rolls, the key aroma-active compounds in the volatile fractions obtained from three different bagel rolls through solvent assisted flavor evaporation (SAFE) were sequentially characterized by an aroma extract dilution analysis (AEDA), quantified by stable isotope dilution and analyzed by odor activity values (OAVs) respectively. Results: Findings revealed 40 aroma-active compounds with flavor dilution (FD) factor ranges of 2–1024. Of these, 22 compounds (FD ≥ 16) were quantified by stable isotope dilution assays (SIDA). Subsequent analysis of the 22 compounds by odor activity values (OAVs) revealed 14 compounds with OAVs ≥ 1 and the highest concentrations were obtained for 2,3-butanedione, 2-phenylethanol, 3-methylbutanal and acetoin respectively. Two recombination models of the bagels (i.e. 24 h and 48 h bagels) showed similarity to the corresponding bagels. Omission tests confirmed that 2,3-butanedione (buttery), acetoin (buttery), 2-acetyl-1-pyrroline (roasty), 5-methyl-2-furanmethanol (bread-like), (Z)-4-heptenal (biscuit-like) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone, were the key aroma compounds. Additionally, acetic acid, butanoic acid, 2-phenylethanol (honey-like), 3-methylbutanoic acid, 2/3-methylbutanal, vanillin, 3-methylbutanol, methional were also important odorants of the bagel. Conclusion: Whilst the long, cold fermented bagels exhibited roasty, malty, buttery, baked potato-like, smoky and biscuit-like notes, the control bagels produced similar but less intense odor notes