Ultrasound-Assisted Extraction of Banana and Water Chestnut Peel Phenolics for Improving the Storage Stability of Fish Patties

Abstract

Fish patties are highly susceptible to oxidative and microbial deterioration during chilled storage because of their high moisture content and abundance of polyunsaturated lipids. This study evaluated ultrasound-assisted water chestnut peel extract (WCPE) and banana peel extract (BPE) as natural preservatives in refrigerated fish patties. Dried peel powders were extracted with 70% ethanol (1:10, w/v) using a 20 kHz ultrasonic probe at 50% amplitude for 10 min, followed by filtration and vacuum evaporation. Fish patties were prepared as untreated control or supplemented with 1% or 2% WCPE, 1% or 2% BPE, or combinations of 1% WCPE + 1% BPE and 2% WCPE + 2% BPE, and were evaluated on days 0, 7, 14, and 21 of refrigerated storage. The combined 2% WCPE + 2% BPE treatment showed the strongest overall protection against quality deterioration. On day 21, the TBARS value was 1.29 ± 0.27 compared with 1.71 ± 0.24 in control, while TVB-N was 24.13 ± 0.41 compared with 34.41 ± 0.30 in control. The same treatment maintained the highest DPPH radical-scavenging activity (50.17 ± 3.27) and total phenolic content (129.61 ± 3.27), while restricting the total bacterial count to 3.96 ± 0.54 log CFU/g compared with 8.56 ± 0.62 log CFU/g in control. However, higher extract concentrations reduced several sensory scores, indicating a trade-off between preservation efficacy and sensory acceptability. Overall, the findings demonstrate the potential of water chestnut and banana peel extracts as natural antioxidant and antimicrobial ingredients for improving the refrigerated stability of fish patties, although optimization of extract concentrations is required to achieve an appropriate balance between preservation and sensory quality.