4-Methylesculetin

Consumer demand for natural products is driving innovation in clean label ingredients. Spine grape (Vitis davidii Foex), a wild East Asian species, and its fresh juice show great promise as versatile ingredients because of their rich composition. The present study assessed the physicochemical properties and metabolite profiles of fresh juices from four spine grape cultivars, exploring their application.

The physicochemical properties of spine grape juices highly depended on the cultivar. Total soluble solids ranged from 12.43% to 14.27%, whereas organic acid content varied between 5.35 and 6.85 g L−1. The phenolic content ranged from 520.17 to 611.68 mg L−1, and the anthocyanin content fluctuated from 72.70 to 155.54 mg L−1. Metabolite identification using ultra‐high‐performance liquid chromatography‐quadrupole time‐of‐flight mass spectrometry revealed a total of 116 compounds, including flavonoids, phenolic acids, stilbenes, coumarins, amino acids, peptides, lipids and vitamins. Among these, 68 compounds including well‐known phenolics and 11 bioactive peptides that are less extensively researched, contributed to the biofunctions of spine grape juices. The white juice ‘Baci’ exhibited the highest levels of bioactive compounds, including catechin, procyanidines, resveratrol and antioxidant peptides. This resulted in a significantly higher DPPH (i.e. 2,2‐diphenyl‐1‐picrylhydrazyl) value (8481.78 μmol Trolox equivalents L−1) compared to other red spine grape juices.

This study provides comprehensive insights into spine grape juices, offering valuable guidance for commercial applications. The ‘Tianci’ and ‘Ziqiu’ red grape juices stand out as ideal sensory ingredients because of their favorable physicochemical properties, whereas the ‘Baici’ white spine grape juice, which contains higher levels of bioactive compounds, emerges as a promising functional ingredient. © 2025 Society of Chemical Industry.

Raw fruit ripeness is an important factor affecting fermented noni fruit juice (FNJ). This study investigated the physicochemical properties, active and volatile components, microbiota, and functional characteristics of FNJ prepared from noni fruits at varying ripening stages. The results showed that deacetylasperulosidic acid (203.54-805.89 mg/L) and asperulosidic acid (102.78-393.41 mg/L) were detected across in all FNJs during fermentation. As noni fruit ripens, the levels of octanoic acid and hexanoic acid in FNJs gradually decreased, while the content of esters significantly increased, particularly during the final stage of ripeness. Metagenomic analysis revealed that Acetobacter sp. and Gluconobacter sp. were core microbes responsible for FNJs, primarily contributing to fatty acid metabolism. Correlation analysis further indicated that the fruit's ripeness significantly influenced its functional properties and volatile components of FNJs. This study offered new insights into selecting the optimal ripeness of noni fruits for the preparation of FNJ and its potential industrial applications.