Exploring Cold plasma technology: Enhancements in Carob seed germination, phytochemical Composition, and antioxidant activity.

The cultivation of carob tree does not need many climatic and ecological requirements. The main limit to its large-scale cultivation is the defects for propagation with seeds. Addressing this, our study evaluated the effect of cold plasma pretreatment on carob seed germination. Impressively, cold plasma showcased beneficial effects by significantly increasing water uptake in seeds (CS: 1.71 ± 0.59; PS/3.99 ± 1.56) and decreasing the contact angle from 80.7° to 57.9°, enhancing the seed surface's hydrophilicity. While the germination rate enhancement was subtle, the treatment presented an innovative route to modifying the seed's physiochemical properties. Specifically, storage proteins like albumin, globulin, and prolamin were notably reduced (Albumin (from 7.67 to 4.95 mg/g DW), Globulin (from 8.52 to 5.80 mg/g DW) and Prolamin (from 3.53 to 1.66 mg/g DW)). Additionally, there was a decline in the overall content of polyphenols (from 846.88 to 760.94 mg GAE/100g DW) and flavonoids (from 790.93 to 502.95 mg GAE/100g DW) and a decrease in the ferric reducing power (from 34.48 to 26.39 mg AAE/g DW). However, radical scavenging activity remained consistent. Intriguingly, FTIR-ATR spectral analysis post plasma treatment indicated oxidative alterations in the seed coat, marked by a distinctive intensity at 1732 cm⁻1 . This investigation suggests that the application of eco-friendly technology could provide improvements in seed surface's hydrophilicity, but appropriate conditions could be chosen to increase germination efficiency.