Nutritional and Flavor Improvement of Enzymatic Hydrolysis in Liquefied-Saccharified Foxtail Millet Syrup: Differences Between Drought-Resistant and High-Yield Hybrid Cultivars.

Enzymatic hydrolysis can enhance the flavor and nutrition of foxtail millet beverages, but product quality is also affected by the raw material cultivar. This study clarified the differences between a high-yield hybrid cultivar (Jizajinmiao 3) and a drought-resistant cultivar (Huangjinmiao) in during the enzymatic processing of foxtail millet syrup. The effects of enzymatic hydrolysis on composition, function, and flavor of liquefied-saccharified foxtail millet syrup hydrolysates (LMSHs) were evaluated by measuring peptide, polyphenol, flavonoid, and amino acid contents, antioxidant activities (DPPH, ABTS, reducing capacity and superoxide anion assays), electronic nose, electronic tongue, and SPME-GC-MS analysis. Hydrolysis significantly (p < 0.05) increased the peptide, polyphenol, flavonoid, and amino acid contents of the LMSHs, concurrently enhancing the antioxidant capacity. DPPH radical scavenging rate of HJM group increased from 31.63 ± 2.36% to 78.06 ± 1.96%. The e-nose analysis revealed that the two LMSHs exhibited different change patterns in relative intensity of volatile, and an enhancement in the bitter, umami, and saltiness tastes was observed by the e-tongue. GC-MS identified 28 volatile compounds, with aldehydes being the main flavor contributors. Partial least-squares discriminant analysis (PLS-DA) identified 10 differential volatile compounds with variable importance in projection >1.0. Overall, the drought-resistant cultivar Huangjinmiao showed superior functional and flavor profiles, including higher bioactive content, stronger antioxidant activity, and more abundant volatiles. These findings indicated that enzymatic hydrolysis is an effective technology for enhancing the functional activity and flavor profiles of LMSHs, providing a reference for the differentiated utilization of different foxtail millet cultivars. PRACTICAL APPLICATIONS: This research suggests that enzymatic processing can improve both the health benefits and taste of foxtail millet syrup. This could lead to the development of more nutritious and flavorful foxtail millet-based ingredients for the food industry. It also helps in selecting the best foxtail millet varieties for specific products.