Neem Oil (<i>Azadirachta indica</i> L.) Response Surface Methodology (RSM)-Optimized Nanoemulsions for Sensory Quality Preservation of <i>Oreochromis niloticus</i> Fillets
Neem oil nanoemulsions (NO NEs) have gained attention as natural antibacterial agents due to toxicity concerns surrounding synthetic preservatives. This study aimed to prepare a response surface methodology (RSM)-optimized NO NE < 200 nm to achieve a stable dip solution to maintain the sensory qu...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-04-01
|
| Series: | Biology |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2079-7737/14/4/400 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Neem oil nanoemulsions (NO NEs) have gained attention as natural antibacterial agents due to toxicity concerns surrounding synthetic preservatives. This study aimed to prepare a response surface methodology (RSM)-optimized NO NE < 200 nm to achieve a stable dip solution to maintain the sensory quality of <i>Oreochromis niloticus</i> fillets. The NO NE achieved a stable formulation with a particle size of 160.2 ± 0.04 nm on average. The polydispersity index (PDI) was 0.1 ± 0.05, and the zeta potential was found to be 18.2 ± 0.09 mV. Gas chromatography confirmed the presence of nimbiol, nimbandiol, 6-deacetyl nimbinene, and azadirachtin in NO after ultrasonic homogenization for 10 min (alternating between 30 s rest and 30 s work time). The NE had a spherical shape with a smooth surface, as was evident from transmission electron microscopy (TEM). Furthermore, NO:PM (neem oil–potassium metabisulphite) had an MIC (minimum inhibitory concentration) value of 150 ppm, compared to 210 ppm for the NO NE alone, against <i>Staphylococcus aureus</i>. Time–kill dynamics revealed the more effective control of <i>S. aureus</i> until 72 h with NO:PM. Moreover, DNA and protein leakage also increased from 0.145 ± 0.001 to 0.769 ± 0.002 OD (optical density) and from 0.142 ± 0.002 to 0.740 ± 0.001 OD, respectively, with the co-formulation of NO:PM. Conclusively, NO:PM inhibited <i>S. aureus</i> at a lower dose compared to the NO NE alone. Time–kill dynamics revealed complete inhibition of <i>S. aureus</i> in vitro for a period of 72 h. On the other hand, a proximate analysis of <i>O. niloticus</i> fillets showed no alteration in pH, no protein loss, and juiciness/moisture retention during 30 days of storage (4 °C). Sensory panelists reported that <i>O. niloticus</i> fillets treated with NE NO had improved color, flavor, juiciness, aroma, and overall quality. These results show that NE NO is a suitable green preservative for fish and possibly other meat-based products. |
|---|---|
| ISSN: | 2079-7737 |