In terms of the sensory characteristics of tomato, fruit texture is important for consumer acceptance. The fruit texture can be measured with instruments like texture profile analyzers or through sensory evaluation, and depends on several factors, including salt stress and cultivar. Additionally, alterations in pectin composition and metabolizing enzymes contributes to changes in fruit texture. However, cultivar differences regarding pectin content and pectin-metabolizing enzymes, the effect of salt stress on fruit texture and their relationships are often overlooked. This study tested whether the effect of salt stress on consumers’ evaluation of hardness, fruit texture, and pectin metabolism varied between three tomato cultivars; a cherry-type ‘cf Kosuzu’, a large-type ‘cf Momotaro Fight’, and a medium-large type ‘Celeb Sweet’. Salt stress was applied by adding 100 mM NaCl to the nutrient solution. The salt-induced changes in consumer evaluations of hardness and fruit texture depending on the cultivar; the evaluation of the large tomato type was higher than that of the cherry and medium-large types. Salt-stressed fruits of the large type exhibited increased pectin content and pectin-metabolizing enzymes, including pectin methylesterase (PME) and polygalacturonase (PG), compared to the cherry and medium-large types. Additionally, in a correlation network, PME and PG were connected by the consumers’ evaluations of hardness. Our results indicate that consumers’ evaluation of hardness, texture profile, and pectin metabolism varied across the three tomato cultivars. We infer that salt stress had a greater impact on the texture attributes of large-type fruits. Furthermore, pectin metabolism may contribute to cultivar variations in the effects of salt stress on fruit texture and the sensory evaluation of hardness.
Zushi et al. (Thu,) studied this question.