Influence of temperature and plant density on sensory quality and volatile terpenoids of carrot (Daucus carota L.) root

Abstract

Carrots were grown in controlled climate chambers at 9, 12, 15, 18 and 21°C and at two plant densities. Descriptive sensory analysis was performed and terpenes were assessed by means of a dynamic headspace technique. The highest score for sweet taste was obtained in carrots grown at the lowest temperature, while bitter taste, terpenes and sugars showed increasing values with increasing growth temperature. Plant density had little or no effect on sensory quality or terpenoid volatiles. Higher temperatures (18 and 21°C) led to higher contents of terpenoid volatiles in carrots. A high positive correlation between terpenes (a-terpinene, b-myrcene, trans-caryophyllene, farnesene, ahumulene) and sensory variables (terpene flavour, green flavour, earthy flavour, bitter taste, aftertaste) was found: 83% of the variation in terpenes was able to predict 82% of the sensory variables by means of partial least squares regression (PLS2). It was concluded that these terpenes were responsible for bitter taste and thus suppressed the perception of sweet taste in carrots. Terpinolene decreased with increasing growth temperature and probably plays only a minor role in masking sweet taste in carrots.

Training of a sensory panel and profiling of winter hardy and coloured carrot genotypes

“…A high correlation is found for the ''negatively" perceived attributes burning aftertaste, bitterness, terpene flavour and silage aroma, which are inversely correlated to the more ''positive" attributes as carrot and nutty flavour. These correlations are also found by Varming et al Table 3 Mean value for 16 carrot genotypes for 13 sensory attributes Genotypes (2004), Rosenfeld et al (2002) and Seljåsen, Hoftun, and Bengtsson (2000). Rosenfeld et al (2002) examined sensory quality of carrot roots and found the attributes sweet taste, crispness, juiciness and acidic taste to correlate inversely to terpene odour, green odour, terpene flavour, bitter taste, bitter aftertaste and others.…”

“…These correlations are also found by Varming et al Table 3 Mean value for 16 carrot genotypes for 13 sensory attributes Genotypes (2004), Rosenfeld et al (2002) and Seljåsen, Hoftun, and Bengtsson (2000). Rosenfeld et al (2002) examined sensory quality of carrot roots and found the attributes sweet taste, crispness, juiciness and acidic taste to correlate inversely to terpene odour, green odour, terpene flavour, bitter taste, bitter aftertaste and others. Varming et al (2004) examined eating quality of raw carrots and found the attributes fruity taste, carrots aftertaste, nutty taste and sweet taste to correlate inversely to bitter taste, bitter aftertaste, earthy taste and earthy odour when carrying out a APLSR on the results.…”

“…Genetic variation and environmental conditions largely influence the sensory quality of carrots, as they vary in quality even when grown under controlled conditions and sorted with respect to size and shape (Baardseth et al, 1996;Hogstad, Risvik, & Steinsholt, 1997;Rosenfeld, Aaby, & Lea, 2002;Seljåsen, Bengtsson, Hoftun, & Vogt, 2001;Simon, Peterson, & Lindsay, 1980). Carrots can vary in quality dependent on the amount of volatile flavour compounds and non-volatile bitter tastants and sugars, as these compounds influence the sensory perception of the volatile compounds, and thus the total impression of the sensory quality.…”

“…The different assessors participating in a sensory analysis may get ''different" products, hence a training of the panel is very important and the development of a comprehensive set of attributes is essential to achieve a reliable sensory profile of carrots (Byrne, Bak, Bredie, Bertelsen, Rosenfeld et al, 2002;Seljåsen et al, 2001). To achieve this, descriptive terms are to be selected by the criteria; terms should (1) have relevance to the product, (2) discriminate clearly between samples, (3) be non-redundant, and (4) have cognitive clarity to the assessors (Byrne, Bak, et al, 1999;Rødbotten, Kubberød, Lea, & Ueland, 2004).…”

Analysis of volatiles in dehydrated carrot samples by solid‐phase microextraction followed by GC‐MS

“…Along with sugars and other compounds responsible for the bitter off-taste of carrots such as polyacetylenes, isocoumarins and phenolic acids [2,3], volatile components have been reported to be the most influential parameters on consumer acceptance of carrots [4,5]. Varming et al [6] described the correlation between flavour compounds, sensory attributes (odour, taste and aftertaste) and consumer liking test (bitterness, sweetness and liking) when analysing the quality of six carrot cultivars grown at two different locations in Denmark; bitter taste being the sensory attribute correlated to the highest number of aroma variables.…”