Phenolic compound profile and gastrointestinal action of Solanaceae fruits: Species-specific differences.

In this study, the presence of phenolic compounds derived from four Solanaceae fruits (tomato, pepino, tamarillo, and goldenberry) during gastrointestinal digestion and the effect of these compounds on human gut microbiota was investigated. The results indicated that the total phenolic content of all Solanaceae fruits were increased during digestion. Furthermore, the targeted metabolic analysis identified 296 compounds, of which 71 were changed after gastrointestinal digestion in all Solanaceae fruits. Among these changed phenolic compounds, 51.3% phenolic acids and 91% flavonoids presented higher bioaccessibility in pepino and tamarillo, respectively. Moreover, higher levels of glycoside-formed phenolic acids, including dihydroferulic acid glucoside and coumaric acid glucoside, were found in tomato fruits. In addition, tachioside showed the highest bioaccessibility in goldenberry fruits. The intake of Solanaceae fruits during the in vitro fermentation decreased the Firmicutes/Bacteroidetes ratio (F/B) compared with the control (∼15-fold change on average), and goldenberry fruits showed the best effect (F/B = 2.1). Furthermore, tamarillo significantly promoted the growth of Bifidobacterium and short-chain fatty acids production. Overall, this study revealed that Solanaceae fruits had different phenolic compound profiles and health-promoting effects on the gut microbiota. It also provided relevant information to improve the consumption of Solanaceae fruits, mainly tamarillo and goldenberry fruits, due to their gut health-promoting properties, as functional foods.

Physiological and Metabolic Changes in Tamarillo (Solanum betaceum) during Fruit Ripening.

Physiological and metabolic profiles in tamarillo were investigated to reveal the molecular changes during fruit maturation. The firmness, ethylene production, soluble sugar contents, and metabolomic analysis were determined in tamarillo fruit at different maturity stages. The firmness of tamarillo fruit gradually decreased during fruit ripening with increasing fructose and glucose accumulation. The rapid increase in ethylene production was found in mature fruit. Based on the untargeted metabolomic analysis, we found that amino acids, phospholipids, monosaccharides, and vitamin-related metabolites were identified as being changed during ripening. The contents of malic acid and citric acid were significantly decreased in mature fruits. Metabolites involved in phenylpropanoid biosynthesis, phenylalanine metabolism, caffeine metabolism, monoterpenoid biosynthesis, and thiamine metabolism pathways showed high abundance in mature fruits. However, we also found that most of the mature-enhanced metabolites showed reduced abundance in over-mature fruits. These results reveal the molecular profiles during tamarillo fruit maturing and suggest tamarillos have potential benefits with high nutrition and health function.