• Potential sources and therapeutic properties of quercetin. • In recent years, the different novel extractions techniques for the extraction of quercetin. • Non-destructive assessment techniques for the identification of quercetin in recent years. • Innovative drug delivery strategies to improve the bioavailability and providing novel therapeutic approaches.

Strains of Lactobacillus acidophilus WFA1 (KU877440), WFA2 (KU877441), and WFA3 (KU877442) were isolated from indigenous Dahi (yogurt), screened, and selected based on acid and bile tolerance along with the antimicrobial activity. These selected strains were further assessed for their probiotic and functional attributes. Results for simulated gastric and intestinal tolerance/ resistance revealed that all three strains can resist and survive under the following mentioned conditions. To access cell surface hydrophobicity, bacterial adhesion to hydrocarbons (BATH), cellular auto‐aggregation, and salt aggregation were performed. In BATH, adhesion of strains against three hydrocarbons namely xylene, dichloromethane, and hexadecane was conducted. The results show that strains showed the least adhesion to xylene (54.25%) as compared to dichloromethane (55.25%) and hexadecane (56.65%). WFA1 showed maximum adherence percentage (55.48%) followed WFA2 (55.48%) and WFA3 (51.38%). Cellular auto‐aggregation varied from 21.72% to 30.73% for WFA3 and WFA1, respectively. In the salt aggregation test (SAT), WFA1, WFA2, and WFA3 aggregated at 0.6, 1.0, and 2.0 molar concentrations of ammonium sulfate, respectively. PCR amplification of bile salt hydrolase gene (bsh) was performed and sequences were submitted to the public database of NCBI and Gene bank under accession numbers, KY689139, KY689140, and KY689141. Additionally, a cholesterol‐lowering assay was conducted and up to 26% reduction in cholesterol was observed by the strains. Regarding functional properties, exopolysaccharide (EPS) production, and antioxidant potential, strain WFA1 showed promising results EPS (1.027mg/ml), DPPH (80.66%), ABTS (81.97%), and reducing power (1.787). It can be concluded from the present study that the mentioned strains of L. acidophilus (WFA1, WFA2, and WFA3) are strongly hydrophobic; thus having an ability to survive and colonize under the gastrointestinal tract which confirms their probiotic nature. Regarding their functional properties, L. acidophilus WFA1 (KU877440) showed excellent properties of antioxidants and EPS production.

In the current work, surface-enhanced Raman scattering (SERS) based on gold nanoparticles (AuNPs) and silver-coated gold nanoparticles (Au@AgNPs) with coffee ring effect was employed to simultaneously ascertain urea and ammonium sulfate (AmS) in milk. A small drop (2 µL) of milk with adulterants was dried on a gold-coated slide to examine concentrations ranging from 5, 10, 20, 40 and 80 mg/dL based on spectra ranging from 400 to 1500 cm.⁻¹ A uniform distribution of analytes, with enhanced Raman signals was detected in a small region (maximum 1.9 mm) of coffee ring across the centre of coffee ring pattern. Nanoparticles with core (Au) diameter of 26 nm and shell thickness (Ag) of 6.5 nm were confirmed using transmission electron microscopy (TEM) images. A strong Raman peak at 980 cm⁻¹ was assigned to AmS, while that at 1001 cm⁻¹ was ascribed to urea. With AuNPs, coefficients of determination (R²) of 0.9873 and 0.9859 were achieved for urea and AmS, respectively, while for Au@AgNPs values of 0.9827 and 0.9855 were obtained for urea and AmS, respectively. This study revealed that SERS based on coffee ring effect has the potential to be further exploited for detecting other banned and hazardous adulterants in milk and milk products. Graphical Abstract