RESUMO
Salinity stress is a major concern in regions where irrigation relies on saline water. This study aimed to investigate the relative water content (RWC), electrolytic leakage (EL), total chlorophyll content, free amino acid content, and total soluble sugar content were analyzed in different groundnut species subjected to various salinity treatments. The results showed that salinity stress significantly reduced the RWC in groundnut leaves, with A. duranensis (wild type) exhibiting higher RWC values compared to the Arachis hypogaea species. RNA sequencing was performed to identify differentially expressed genes (DEGs) during salt stress. A total of 9079 DEGs were identified, with 1372 genes upregulated and 2509 genes downregulated. Genes belonging to transcription factor families, such as WRKY, MYB, bHLH, E2F, and Auxin efflux carrier proteins, were induced under salt stress in the tolerant genotype. Conversely, genes encoding NADH dehydrogenase, glutathione S-transferase, protein kinases, UDP-glycosyltransferase, and peroxidase were downregulated. Gene ontology and pathway analyses revealed several enriched categories and metabolic pathways associated with salt stress response, including catalytic activity, response to salt stress, ATP-dependent activity, and oxidative phosphorylation. The findings of this study provide insights into the physiological and molecular responses of groundnut to salinity stress. A. duranensis exhibited better salinity tolerance than Arachis hypogaea, as indicated by higher RWC values, lower electrolytic leakage, and differential gene expression patterns. These results contribute to our understanding of the mechanisms underlying salt stress tolerance in groundnut and may guide future efforts to develop salinity-tolerant groundnut species, ultimately improving crop yield in saline-affected regions.
RESUMO
Research background: Peanut oil (Arachis hypogaea L.) is a rich source of unsaturated fatty acids. Its consumption has been reported to have biological effects on human health. Unsaturated, especially polyunsaturated fatty acids (PUFA) found in peanut oil are highly susceptible to oxidation, leading to the formation of harmful compounds during processing and storage. The aim of this study is to prevent the oxidation of peanut oil PUFA by encapsulation in a protein-polysaccharide complex using microwave drying. Experimental approach: The combined effect of corn starch (CS) and whey protein isolate (WPI) was evaluated for ultrasound-assisted microwave encapsulation of peanut oil to prevent oxidative degradation. The effect of independent parameters, viz. CS:WPI mass ratio (1:1 to 5:1), lecithin mass fraction (0-5 %), ultrasonication time (0-10 min) and microwave power (150-750 W) on the encapsulation of peanut oil was evaluated using response surface methodology (RSM). The process responses, viz. viscosity and stability of the emulsion, encapsulation efficiency, peroxide value, antioxidant activity, free fatty acids (FFA), moisture, angle of repose and flowability (Hausner ratio (HR) and Carr's Index (CI)) were recorded and analysed to optimize the independent variables. Results and conclusions: The viscosity of all emulsions prepared for encapsulation by ultrasonication ranged from 0.0069 to 0.0144 Pa·s and more than 90 % of prepared combinations were stable over 7 days. The observed encapsulation efficiency of peanut oil was 21.82-74.25 %. The encapsulation efficiency was significantly affected by the CS:WPI mass ratio and ultrasonication. The peroxide value, antioxidant activity and FFA ranged from 1.789 to 3.723 mg/kg oil, 19.81-72.62 % and 0.042-0.127 %, respectively. Physical properties such as moisture content, angle of repose, HR and CI were 1.94-8.70 %, 46.5-58.3°, 1.117-1.246 and 10.48-22.14 %, respectively. The physical properties were significantly affected by surface properties of the capsules. The higher efficiency (74.25 %) of peanut oil encapsulation was achieved under optimised conditions of CS:WPI mass ratio 1.25, 0.25 % lecithin, 9.99 min ultrasonication and 355.41 W microwave power. Novelty and scientific contribution: The results of this work contribute to the fields of food science and technology by providing a practical approach to preserving the nutritional quality of peanut oil and improving its stability through encapsulation, thereby promoting its potential health benefits to consumers and applications in various industries such as dairy and bakery.
