Tissue specialization at the metabolite level is perceived during the development of tomato fruit

Fruit maturation and tissue differentiation are important topics in plant physiology. These biological phenomena are accompanied by specific alterations in the biological system, such as differences in the type and concentration of metabolites. The secondary metabolism of tomato (Solanum lycopersicum) fruit was monitored by using liquid chromatography (LC) coupled to photo-diode array (PDA) detection, fluorescence detection (FD), and mass spectrometry (MS). Through this integrated approach different classes of compounds were analysed: carotenoids, xanthophylls, chlorophylls, tocopherols, ascorbic acid, flavonoids, phenolic acids, glycoalkaloids, saponins, and other glycosylated derivatives. Related metabolite profiles of peel and flesh were found between several commercial tomato cultivars indicating similar metabolite trends despite the genetic background. For a single tomato cultivar, metabolite profiles of different fruit tissues (vascular attachment region, columella and placenta, epidermis, pericarp, and jelly parenchyma) were examined at the green, breaker, turning, pink, and red stages of fruit development. Unrelated to the chemical nature of the metabolites, behavioural patterns could be assigned to specific ripening stages or tissues. These findings suggest spatio-temporal specificity in the accumulation of endogenous metabolites from tomato fruit.     

Black carrot polyphenols: effect of processing,storage and digestion—an overview

Black carrots represent a valuable source of polyphenols, in particular anthocyanins and phenolic acids, and has attracted the attention of the scientific community especially due to the unique profile of anthocyanin compounds, which are well distinguished for their role in health promotion and prevention of chronic diseases. Black carrots are often not consumed as such, instead they are processed into other products. In general, processed products of black carrot are stored for long term and the polyphenols are susceptible to degradation during storage. In addition, it is also important to determine how the digestion process affects polyphenols as this will, in turn, affect their bioavailability. Accordingly, the potential health-promoting effects of black carrot polyphenols depend on their processing history and their stability during storage as well as their absorption in the gastrointestinal tract. In this perspective, this review provides an overview of the findings on the effects of processing, storage and digestion on black carrot polyphenols.     

Increasing the Bioaccessibility of Antioxidants in Tomato Pomace Using Excipient Emulsions

Plant-based foods contain numerous bioactive constituents (“nutraceuticals”) that have beneficial effects on human health. However, their oral bioavailability is often relatively low, which limits their potential efficacy. The bioavailability of nutraceuticals can be increased through the utilization of excipient foods whose compositions and structures are specifically designed to increase the amount of nutraceuticals absorbed in an active form. In this study, olive oil excipient emulsions were designed to increase the bioaccessibility of lycopene and other natural antioxidants in tomato pomace. These emulsions consisted of 8 wt% olive oil and 1 wt% Tween 20 or Tween 80 and were prepared using a microfluidizer operated under different processing conditions (12,000 or 20,000 psi; 3 or 5 passes). Changes in particle size, charge, and bioaccessibility were assessed when tomato pomace-emulsion mixtures were exposed to simulated gastrointestinal digestion. The mean particle diameter of the particles in the excipient emulsions increased after digestion (416 to 446 nm) compared to the values before digestion (200 to 220 nm). The presence of excipient emulsions significantly increased the bioaccessibility of lycopene in tomato pomace compared to oil-free control samples. For instance, lycopene bioaccessibility was > 82% when the tomato pomace was mixed with excipient emulsions but only 29% when it was mixed with oil-free buffer solutions. The presence of excipient emulsions also increased the total phenolic content of the tomato pomace. For instance, the phenolic content was considerably higher in the presence of excipient emulsions (1489 to 2055 mg GAE /100 g FW) than in their absence (939 mg GAE /100 g FW). However, the excipient emulsions did not increase naringenin bioaccessibility, which was attributed to the fact that it was not strongly hydrophobic. The efficacy of the excipient emulsions was only modestly dependent on emulsifier type and homogenization conditions. In conclusion, excipient emulsions can be designed to enhance the bioaccessibility of strongly hydrophobic nutraceuticals in tomato-based products, which may boost their healthiness.

Graphical abstract