ULTRASOUND AND YEAST FERMENTATION MODULATE BIOACTIVE AMINES AND ENHANCE POLYAMINE LEVELS IN CASHEW APPLE BAGASSE FLOUR

Cashew apple bagasse is an agro-industrial by-product rich in compounds of nutritional and functional interest, and its utilization may reduce food waste while providing ingredients with high added value. Technologies such as ultrasound and controlled fermentation can modify the plant matrix and alter the availability and profile of bioactive compounds. Therefore, this study aimed to evaluate these technologies’ potential to enhance the functional value of cashew apple bagasse flour, with emphasis on its bioactive amine profile. Ripe cashew apples (25 kg, Anacardium occidentale L., clone CCP 76) were purchased from CeasaMinas, Contagem, MG, Brazil. After sanitization and juice extraction, the resulting bagasse was divided into five treatments in triplicate (5 × 3): control (C), ultrasonic bath treatment (UB), probe ultrasound treatment (PU), 48-h fermentation with Saccharomyces cerevisiae (SCF), and 96-h fermentation with Starmerella meliponinorum (SMF). Afterwards, the bagasse samples were dried at 55 °C and ground (32 mesh). Unprocessed wet cashew apple bagasse (WCB) was used as a reference. Nine bioactive amines were separated by ion-pair HPLC, and quantified after post-column derivatization with o-phthalaldehyde and fluorimetric detection (340/450 nm). Data were subjected to ANOVA and the means were compared by Tukey’s test (p ≤ 0.05). WCB contained putrescine (34.00 mg/kg), agmatine (1.26 mg/kg), spermidine (51.25 mg/kg), spermine (7.69 mg/kg) and phenylethylamine (19.33 mg/kg). The treatments significantly altered the amine profile. Putrescine, agmatine, and spermidine increased from 49.83, 2.58, and 73.80 mg/kg in the control to 88.00–92.99, 4.29–4.74, and 155.07–175.45 mg/kg in the pretreated flours, respectively. These increases may be attributed to ultrasound-induced structural changes in the food matrix, enhancing amine extractability, and to the potential production of these compounds through yeast metabolism during fermentation. Spermine concentrations were higher in the fermented flours, reaching 26.06 mg/kg in SCF and 30.14 mg/kg in SMF (p < 0.05) compared to the control. Increases in spermidine and spermine are particularly relevant given the growing interest in these polyamines as modulators of processes associated with healthy aging. Spermidine has been associated with autophagy induction, maintenance of mitochondrial function, and proteostasis, whereas recent evidence suggests that spermine may contribute to cellular homeostasis by inhibiting ferroptosis. Phenylethylamine did not differ among treatments, whereas tyramine and serotonin were not detected. Cadaverine reached 13.57 ± 1.76 mg/kg in SMF, while histamine was detected mainly in ultrasound-treated samples possibly due to enhanced extractability resulting from ultrasound-induced structural changes in the food matrix, as suggested by ultrasound-assisted analytical extraction studies. Overall, ultrasound and controlled fermentation substantially modified the bioactive amine profile of cashew apple bagasse flour, particularly by increasing spermidine and spermine levels, highlighting the potential of these technologies for the functional valorization of this agro-industrial by-product.