Sweet taste in apple: the role of sorbitol, individual sugars, organic acids and volatile compounds

Abstract

Sweetness is one of the main drivers of consumer preference, and thus is given high priority in apple breeding programmes. Due to the complexity of sweetness evaluation, soluble solid content (SSC) is commonly used as an estimation of this trait. Nevertheless, it has been demonstrated that SSC and sweet taste are poorly correlated. Though individual sugar content may vary greatly between and within apple cultivars, no previous study has tried to investigate the relationship between the amount of individual sugars, or ratios of these, and apple sweetness. In this work, we quantified the major sugars (sucrose, glucose, fructose, xylose) and sorbitol and explored their influence on perceived sweetness in apple; we also related this to malic acid content, SSC and volatile compounds. Our data confirmed that the correlation between sweetness and SSC is weak. We found that sorbitol content correlates (similarly to SSC) with perceived sweetness better than any other single sugar or total sugar content. The single sugars show no differentiable importance in determining apple sweetness. Our predictive model based on partial least squares regression shows that after sorbitol and SSC, the most important contribution to apple sweetness is provided by several volatile compounds, mainly esters and farnesene.

A comparison of the chemical composition and antioxidant activity of several new early‐ to mid‐season apple cultivars for a warmer climate with traditional cultivars

“…It has been reported that apples that bloom earlier tend to taste sweeter . Sweet taste in apples might be correlated with free sugar content . Little information is available about the nutritional components, such as free sugars and organic acids, in these new apple cultivars.…”

The Influence of Osmotic Dehydration in Polyols Solutions on Sugar Profiles and Color Changes of Apple Tissue

“…The values of sorbitol content observed by researchers, related to a cultivar of fruit. Aprea et al [30] noted values between 1.3 and 12.9 g/kg (average 5.5 g/kg) in 17 different cultivar/accessions. Wider range of the level of sorbitol has been reported by Wang et al [29] -between 0.0 and 15.3 g/L (average 4.3 g/L) -the values marked in 62 apple cultivars.…”

Flavor and Texture Characteristics of ‘Fuji’ and Related Apple (Malus domestica L.) Cultivars, Focusing on the Rich Watercore

“…Recently, the importance of aroma components in the characteristics of flavor and preference in apple has been widely recognized. Aprea et al [11] reported that sorbitol content correlated with perceived sweetness better than any other single sugar or total sugar content. Furthermore, their predictive model based on partial least squares regression included not only SSC but also volatile compounds and revealed that several volatiles are possibly contributing to flavor.…”

“…Furthermore, the rich watercore trait has become a breeding target with the aim of increasing the sweet flavor in apple [10]. Aprea et al [11] proposed that apple breeding programs must take into account factors such as volatile compounds, texture parameters, minor components, and information from sensory panels. However, perceived sweetness is difficult to be described because it is always perceived in combination with other sensory properties, which influence its evaluation.…”