The relationship between instrumental tests and sensory determinations of peach and nectarine texture

In this work, we evaluate the relationship between the rheological and the sensory texture of fresh peach and nectarine varieties. Two non-melting fleshed varieties (NMF), 'Andross' and 'Carson, and four melting fleshed nectarines (MF), 'Andes nec-1', 'Andes nec-2, 'Andes nec-3', and 'Venus, were harvested and kept in a ripening chamber for four days. A sensory trained panel using the sensory texture descriptors 'hardness, 'crispness, 'crunchiness, 'melting, and 'juiciness' determined the sensory profile of each variety. Penetration tests, texture profile analysis (TPA), and mechanical acoustic analysis profile tests were performed using a TA-XT Plus texture meter. Principal component analysis defined the most influential rheological variables of each test. We also performed regression analysis by partial least squares (RPLS); as regressor variables we used the set of the rheological variables and the sensory attributes as dependent variables. The RPLS model explained 62% of the relationship between rheological and sensory variables. The strongest relationships were between 'hardness' and the TPA variables, and 'melting' and quantity of juice and the TPA variables. Finally, using a regression tree for the attributes 'hardness' and 'melting, we determined that the variable 'TPA hardness' was the most relevant to define both descriptors, thus classifying the varieties into two groups by obtaining a critical value for each attribute.