Sensory analysis for quality assessment of mini-watermelon fruits grafted on different rootstocks.

A possible alternative to the use of agrochemicals for soil disinfestations in Cucurbitaceae cultivation is the use of grafted plants. The increasing consumer attention for high quality vegetable crops makes necessary to carefully select rootstocks/scion combinations. In this regards the research aimed to the evaluation of the effects of different rootstocks, selected for their resistance to diseases, on the sensory quality of mini-watermelon fruits (Citrullus lanatus [Thumb.] Matsum. and Nakai cv. Minirossa) fruits. The plants of mini-watermelon were cultivated under greenhouse conditions in Pachino (Syracuse, Italy). The sensory profile (UNI 10957, 2003) was defined by a panel of 10 judges, that have evaluated the intensity of each attributes by assigning a score between 1 (absence of the sensation) and 9 (extremely intense). The 16 sensory attributes used by judges were: 1 for appearance (colour of flesh), 4 for aroma (melon, fruity, herbaceous, pumpkin, off-odour), 2 for taste (sour and sweet), 2 for rheological properties (flesh firmness and juiciness), 4 for flavour (melon, fruity, herbaceous, pumpkin, off-flavour) and overall. The effect of the selected rootstocks on physico-chemical and microbiological parameters and volatile aroma profile were considered, too. Volatile aroma constituents were extracted and analyzed by SPME-GC-MS; the amount of each component was determined. Volatile aroma compounds and sensory data were correlated each other. All the results were elaborated statistically in order to identify the most appropriate rootstock. The data evidenced that some rootstocks, easily available on the market, can be successfully used for controlling soil pathogens without determining relevant changes on the sensory quality of the fruits. The research also emphasized the usefulness of sensory analysis in fruit quality determination and showed the numerous relationships among sensory descriptors and instrumental volatile data.