Flavoromics Analysis Reveals Sex- And Size-Dependent Volatile Flavor Signatures in Cherax quadricarinatus Muscle Under Identical Farming Conditions

The red-claw crayfish, Cherax quadricarinatus, is a commercially valuable freshwater aquaculture species, with muscle flavor representing a core trait driving consumer preference and market value. Under identical farming conditions, same-batch crayfish commonly develop marked size divergence within and between sexes, but the impacts of this variation on muscle volatile flavor profiles remain largely unexplored. Here, C. quadricarinatus reared under consistent environmental conditions were categorized into four groups by body weight and sex: large-size female (GUBF), large-size male (GUBM), small-size female (GUSF), and small-size male (GUSM). Headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME/GC-MS) was employed to profile volatile organic compounds. Multivariate statistical analysis, relative odor activity value calculation, metabolic pathway and network analysis, and receiver operating characteristic (ROC) analysis were combined to dissect flavor variation patterns, identify key aroma compounds, reveal underlying metabolic mechanisms, and screen potential biomarkers. Proximate composition analysis showed significant size differences in crude protein, lipid, moisture, and meat yield, with no significant sex differences. One hundred thirty-six volatile metabolites across 15 chemical categories were identified in all samples. Multivariate statistical analyses revealed clear separation among the four groups, suggesting that both body size and sex shape muscle volatile metabolite profiles, with stronger effects observed in females. Thirty-eight shared aroma-active compounds were detected, mainly including alcohols, aldehydes, ketones, esters, and aromatic hydrocarbons. The overall sensory profile was dominated by sweet-like notes, followed by fruity and green notes. Sex-related flavor differences were relatively slight in large-size crayfish but pronounced in small-size individuals. Large-size female crayfish had simpler flavor composition, while small-size females showed higher diversity and abundance of flavor compounds; size variation had limited effects on male flavor. Butanoate metabolism was significantly enriched in both the small-size sex comparison and female size comparison. Core metabolic frameworks were generally conserved across groups, but key hub metabolites differed by comparison type. This study systematically characterized the volatile flavor profiles of C. quadricarinatus muscle across different body sizes and sexes under controlled farming conditions, providing preliminary references for quality evaluation and premium aquaculture optimization of C. quadricarinatus.