A combined sensory-instrumental tool for apple quality evaluation

Abstract

A combined approach for perceptible quality profiling of apples based on sensory and instrumental techniques was developed. This work studied the correlation between sensory and instrumental data, and defined proper models for predicting sensory properties through instrumental measurements. Descriptive sensory analysis performed by a trained panel was carried out during two consecutive years, on a total of 27 apple cultivars assessed after two months postharvest storage. The 11 attributes included in the sensory vocabulary discriminated among the different apple cultivars by describing their sensory properties. Simultaneous instrumental profiling including colorimeter, texture analyser (measuring mechanical and acoustic parameters) and basic chemical measurements, provided a description of the cultivars consistent with the sensory profiles. Regression analyses showed effective predictive models for all sensory attributes (Q 2 ≥ 0.8), except for green flesh colour and astringency, that were less effective (Q 2 = 0.5 for both). Interesting relationships were found between taste perception and flesh appearance, and the combination of chemical and colorimeter data led to the development of an effective prediction model for sweet taste. Thus, the innovative sensory-instrumental tool described here can be proposed for the reliable prediction of apple sensory properties.

Annual variation in sensory characteristics of seventeen apple cultivars

“…Astringency is related to the quantity and quality of phenolic compounds, which are greatly affected by the harvest year (Łata and Tomala 2007, Belviso et al 2013). Corollaro et al (2014) showed that astringency is difficult to predict with instrumental data, but it highly correlates with perceived sourness, an association also observed in the present study.…”

“…The first PC formed a grainy-juicy-crunchy continuum and the second a sour-sweet continuum, similar to our sensory space of the first and second PCs. The graph by Corollaro et al (2014) showed some year effect, the magnitude and direction of which varied depending on the cultivar, and thus resembled our results considerably.In our PCA, texture attributes loaded on the first and third PC and flavour attributes on the first and second PC. The loading pattern resembled the PCA graph extracted from the storage life data in 2010 (Seppä et al 2013a), which indicated a clear trend towards mealier texture with less flavour intensity during advanced storage time.…”

“…Astringency is related to the quantity and quality of phenolic compounds, which are greatly affected by the harvest year (Łata and Tomala 2007, Belviso et al 2013). Corollaro et al (2014) showed that astringency is difficult to predict with instrumental data, but it highly correlates with perceived sourness, an association also observed in the present study.The sensory data by Corollaro et al (2014), based on evaluation of 27 apple cultivars in Italy, loaded on two PCs. The first PC formed a grainy-juicy-crunchy continuum and the second a sour-sweet continuum, similar to our sensory space of the first and second PCs.…”

“…The sensory data by Corollaro et al (2014), based on evaluation of 27 apple cultivars in Italy, loaded on two PCs. The first PC formed a grainy-juicy-crunchy continuum and the second a sour-sweet continuum, similar to our sensory space of the first and second PCs.…”

“…At the same time, soluble solids concentration increased by 0.20-0.28 °Brix per decade. These changes most probably affect the sensory quality and consequently, acceptability of apples, although the content of individual sugars or soluble solids concentration is not directly related to sweetness (Harker et al 2002, Railio 2010, Corollaro et al 2014.In spite of the research findings mentioned above, little is known about the effect of the annual variation of weather on the sensory quality and thus, consumer quality of apples. The stability of the sensory characteristics of domestic apples in the market is important for the consumers (Malkki 2007, Seppä 2014.…”