Sastia Prama Putri

This study aimed to improve the functional properties of tempe. We applied three treatments to increase gamma-aminobutyric acid (GABA) content in tempe and analysed the results. Anaerobic 24h treatment was the most effective and increased the GABA content in tempe by 16-fold. Furthermore, a comprehensive analysis of the components using metabolomics revealed that BCAAs and tryptophan as well as GABA, significantly increased. Tempe treated anaerobically for 24 h showed higher α-glucosidase inhibitory activity than normal tempe. In addition, GABA and tryptophan inhibited α-glucosidase activity, suggesting that the increase in GABA and tryptophan following anaerobic 24 h treatment may associate with the increase of α-glucosidase inhibitory activity in tempe. These results indicate that anaerobic 24 h treatment is a promising method for increasing the value of tempe as a functional food.

Premium black tea varieties with strong agronomic performance and desirable flavor profiles are essential for consumer acceptance and producer competitiveness. This need continues to drive breeding programs and scientific evaluation of black tea varieties. This study evaluated the sensory attributes, agronomic traits, and metabolite profiles of promising hybrid and traditional black tea varieties grown and processed under identical conditions in Central Java Indonesia. Sensory analysis showed that the hybrids exhibited a lighter taste and color than traditional varieties, with clear separation (PC1: 83.5%). These results aligned with their metabolite profiles: hybrid tea contained significantly lower levels of some flavonoid compounds and higher concentrations of amino acids, several organic acids, and some sugars (p < 0.05). For volatile compounds, hybrids were characterized by higher levels of aldehydes, alcohols, and pyrazines, contributing to their flavor quality. This comparative assessment provides insight into how hybridization influences quality and agronomic performance, supporting future efforts in black tea improvement and authentication.

Microwave (MA)‐ and ultrasonic‐assisted (UA) alkalization were applied to cocoa powders for 5, 10, and 15 min to investigate their effects on metabolite composition, sensory profile, and consumer liking. Widely targeted gas chromatography–mass spectrometry (GC‐MS) analysis showed alkalization altered metabolite profiles: Natural cocoa powders contained more amino acids, sugars, and flavonoids, while alkalized samples had elevated organic acids. Compared to conventionally alkalized (CA) samples, only UA15 showed a significant increase in 3,4‐dihydroxybenzoic acid. UA15 also exhibited the greatest reduction in reducing sugars and hydrophobic amino acids, specific precursors for cocoa aroma via the Maillard reaction. Headspace solid‐phase microextraction GC‐MS revealed that alkalized samples contained more Maillard‐reaction‐derived aroma‐active compounds, including aldehydes, esters, ketones, pyrazines, and furan, with UA15 showing the highest levels, suggesting enhanced Maillard activity. MA10 and UA5 had elevated n‐hexadecane and 2,3‐pentanedione, suggesting enhanced release and fragmentation–recombination of sugar‐derived intermediates. Rate‐All‐That‐Apply results showed alkalized samples were associated with sweeter and more intense cocoa flavor. Hedonic test results indicated consumers preferred alkalized samples over natural cocoa powder, which was perceived as overly acidic and burnt. However, differences in sensory attributes and overall liking among the alkalized samples were not significant and showed high variability, suggesting that consumer panelists cannot detect subtle sensory differences between CA, MA, and UA samples. Future studies should focus on determining the appropriate MA and UA treatment conditions to produce cocoa powders that better meet consumer preferences. This is the first report on MA and UA alkalization effects on cocoa powder quality and offers valuable insights for product development using hybrid alkalization processes. Practical Applications: The changes in the sensory and chemical profiles of cocoa powders upon microwave‐assisted and ultrasonic‐assisted alkalization were revealed. This information on the effect of the hybrid alkalization process on food quality and consumer preference of the cocoa powders is of value for consideration in cocoa powder processing and development.

Rifqi Ahmad Riyanto, Eiichiro Fukusaki, and Sastia Prama Putri. Prev Nutr Food Sci 2025;30:370-8. https://doi.org/10.3746/pnf.2025.30.4.370