Test Aroma Research Articles

Evaluation of aroma in rice(Oryza sativa L.) using KOH method, molecular markers and measurement of 2-acetyl-1-pyrroline concentration

The sensory test of leaf aroma using a 1.7% KOH solution for 70 rice cultivars originating from nine Asian countries indicated the existence of a strong correspondence of the aroma character with the tasting of individual grains. The sensory test appeared to be a simple and reliable method for rapid identification of aromatic rice. We could not find any universal specific molecular marker suitable for the identification of the aroma trait in rice although the SSR marker RM17 could distinguish the aromatic Vietnamese cultivars. We used three F2 populations of aromatic and nonaromatic cultivars as parents to study the mode of inheritance of the aroma trait. Monogenic recessive inheritance of the aroma trait was observed in Jasmine 85 and Khao Dawk Mali 105, whereas Hoa Lai harbored two recessive genes for the aroma trait. Quantitative analysis of the aromatic compound 2-acetyl-1-pyrroline suggested that the expression of the aroma trait was controlled by different genetic factors in addition to the influence of environmental conditions. These results confirmed that aroma in rice is a quantitative character and that several genes are involved in the expression of the aroma trait in rice.

BOYSENBERRY -A CHARACTER DESCRIPTION FOR COMMERCE

A description of Boysenberry (Rubus ursinus hybrid), using characteristics that are important for the majority of processors, has been developed. This will enable verification and the detection of adulterations in Boysenberry products and the establishment of boundaries defining new Boysenberry cultivars within breeding programmes. In the 1997/98 and 1998/99 seasons, Boysenberries and a range of other Rubus fruits were analysed for anthocyanin pigments using HPLC. The main anthocyanins of Boysenberries were cyanidin 3-sophoroside (cy-sop), cyanidin 3-rutinoside-5-glucoside (cy-glurut), cyanidin 3-glucoside, (cy-glu) with minor amounts of cyanidin 3-rutinoside (cy-rut). The cy-sop/cy-glu ratio appeared to distinguish Boysenberry from other berry types. Aroma tests appeared promising as a further test to distinguish Boysenberry from other Rubus, as an untrained taste panel was able to distinguish Boysenberries from the other samples. Headspace analysis was used to analyse the fruit samples for volatiles. High levels of linalool were associated with Boysenberry, Loganberry and Youngberry fruit but no volatiles unique to commercially acceptable Boysenberry were identified. Unripe fruit showed lower levels of volatiles, which could limit the ability to distinguish between fruit types using this.

Judge selection for hard and semi-hard cheese sensory evaluation

During a five month period, 34 potential panellists were subjected to 21 selection tests (triangular test, threshold evaluation, ranking test and stimulus recognition test) based on taste, aroma and textural characteristics of cheese. Standardised available ricotta cheese was used as a substrate in taste and aroma tests, while commercially available cheese was utilised to evaluate candidate performance in textural characteristic tests. A combination of procedures (binomial, sequential and bi-plot) allowed the definition of homogeneous subsets of candidates suitable for different analysis. The binomial approach allowed the last performing candidates to be identified while the sequential procedure enhanced our understanding of their skills. To make the selection criteria more coherent the performance parameters were objectively derived from the array of tests. Candidates were classified into three groups, depending on their capabilities, and the different discrimination power of the tests was highlighted through bi-plots.

Bioconversion of Citrus Aroma Compounds by Pichia pastoris

ABSTRACTAfter induction of alcohol oxidase, active Pichia pastoris cells were grown in model alcohol solutions and orange aroma, a by‐product rich in potential alcohol substrates for bio‐oxidation to aldehydes. Acetaldehyde production efficiency was 60% at 0.1% ethanol, decreasing with increasing ethanol. Acetaldehyde, propanal, and octanal were generated using the Pichia system with orange aroma as substrate. Acetaldehyde concentration doubled during a 24h reaction time at 30°C. In contrast to use of isolated alcohol oxidase, the whole cell system had the advantage of cofactor regeneration and associated enzyme systems, including formaldehyde dehydrogenase. Sensory differences were found in the full strength biomodified aroma. Presented in a paired comparison aroma test, to a trained panel it rated higher for the attributes orange character, freshness, and fruitiness than the unmodified control.

Isolation of peppermint oil using supercritical co2 extraction

AbstractPeppermint leaf oil was isolated by a supercritical fluid extraction (SFE) using CO2 in which the extraction was followed by a two‐stage fractional separation. Chemical analysis revealed that oils extracted under different SFE conditions possessed a widely different percentage composition. The percentage of co‐extracted cuticular waxes varied too. Oil obtained by hydrodistillation was also compared with the extracted oils. Although practically the same compounds were present in the hydrodistilled oil, its composition was similar to SFE oil extracted under non‐optimized conditions. Qualitative aroma tests showed that the oil obtained at optimum SFE conditions (p = 90 bar, T = 50°C) had a fragrance that better resembled that of the peppermint leaves used for the extraction of the oils.