Postharvest UV-B exposure drives changes in primary metabolism, phenolic concentration, and volatilome profile in berries of different grape (Vitis vinifera L.) varieties

BACKGROUND The ultraviolet-B (UV-B) radiation can alter grape metabolism during berry development, but little is known on the effect of postharvest UV-B exposure. In this study, we evaluated the effect of postharvest UV-B exposure on berry primary and secondary metabolites in four grapevine varieties (Aleatico, Moscato bianco, Sangiovese, and Vermentino) in order to evaluate the possibility to increase the grape quality and its nutraceutical properties. RESULTS The treatment did not significantly affect the berry primary metabolism in terms of organic acids, carbohydrates, and amino acids profile, regardless of the variety. UV-B exposure reduced the total anthocyanin content, particularly the tri-substituted and di-substituted forms in Aleatico and Sangiovese, respectively. An overall negative effect of UV-B irradiation on the flavonols profile of Aleatico, Moscato bianco, and Vermentino berries was found, whereas it enhanced the quercetin, myricetin and kaempferol concentration in Sangiovese. The free fraction of berry volatile organic compounds increased in UV-B-treated Aleatico and Moscato bianco berries, especially C-13-norisoprenoids and volatile phenols, as well as key monoterpenes, such as the linalool derivatives. However, higher concentrations of glycosylated monoterpenes and C-13-norisoprenoids were measured in Sangiovese and Vermentino berries treated with UV-B. CONCLUSION This study provides new insights on the effect of postharvest UV-B radiation on berry secondary metabolism, highlighting a different modulation between varieties and suggesting the potential use of this technique to increase some nutraceutical and quality characteristics of grape berry

Effects of Lactiplantibacillus plantarum and Lacticaseibacillus paracasei supplementation on the faecal metabolome in children with coeliac disease autoimmunity : a randomised, double-blinded placebo-controlled clinical trial

Introduction: Coeliac disease is a lifelong immune-mediated enteropathy manifested as gluten intolerance in individuals carrying specific human leukocyte antigen (HLA) molecules. Other factors than genetics and gluten intake, however, may play a role in triggering the disease. The gut internal environment is thought to be one of these potential contributing factors, and it can be influenced throughout life. Methods: We examine the impact of Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 supplementation on the faecal metabolome in genetically predisposed children having tissue transglutaminase autoantibodies, i.e., coeliac disease autoimmunity. Probiotic strains were selected based on their beneficial properties, including mucosal permeability and immune modulation effects. The intervention group (n = 40) and control group (n = 38) took the probiotics or placebo daily for 6 months in a double-blinded randomised trial. Faecal samples were collected at baseline and after 3 and 6 months and analysed using the 1H NMR for metabolome. The incorporation of 16S rRNA sequencing as a supportive dataset complemented the analysis of the metabolome data. Results: During the 6 months of intervention, the stool concentrations of 4-hydroxyphenylacetate increased in the intervention group as compared to controls, whereas concentrations of threonine, valine, leucine, isoleucine, methionine, phenylalanine, aspartate, and fumarate decreased. Additionally, a noteworthy effect on the glycine, serine, and threonine metabolic pathway has been observed. Conclusion: The findings suggest a modest yet significant impact of the probiotics on the faecal metabolome, primarily influencing proteolytic processes in the gut. Clinical trial registration: ClinicalTrials.gov, NCT03176095