Research Topic: Quality evolution, maturation, microbial succession and digestive fate of Citri Reticulatae Pericarpium (CRP)
Abstract: ** Lecture will be given in English**
Citri Reticulatae Pericarpium (CRP), particularly the pericarp of Citrus reticulata ‘Chachi’ (GCP), is widely used in China as food and herbal medicine, with quality improving during aging. However, the dynamic changes and the underlying microbial shifts during storage remain poorly understood, particularly with respect to bioactivity and digestibility. This study investigated how environmental factors (storage conditions, aging time, and origin) influence quality, digestive fate, microbial succession, and metabolite transformation, as well as microbiome–metabolome interactions involved in GCP quality variation.
We first evaluated the effects of storage conditions (temperature and humidity) and aging time on aged GCP. Real-time monitoring of microbial respiration (O2, CO2, and CH4) and volatile organic compounds (VOCs), and flavonoid determinations suggested active microbial metabolism as a potential key driver of quality. Multi-omics analyses revealed that microbial genera such as Aspergillus, Cladosporium, Xeromyces, and Pseudomonas were significantly associated with flavonoids, particularly hesperidin and didymin. Functional prediction further indicated microbial pathways involved in metabolite transformations. The functional implications of aging on consumer exposure were further assessed using in vitro digestion simulations, showing that the bioaccessibility of hesperidin in GCP decoctions remained relatively stable (~30–50%) regardless of aging time or consumer’s sex. In a subsequent investigation focusing on early-stage aging, freshly dried citrus peels were monitored over the course of 12 months. Color development was accompanied by varying levels of flavonoids, volatile and non-volatile metabolites. The initial microbial succession was characterized by the dominance of genera such as Methylobacterium, Sphingomonas, Cladosporium, and Zasmidium. Collectively, our results suggest that the first year is critical for the quality evolution of GCP. Overall, these findings highlight the important role of microbial communities in mediating bioactive compound transformations, providing a theoretical basis for optimizing storage, standardizing the aging process, and enhancing the quality of GCP.
