Surface-enhanced Raman scattering (SERS) is an emerging swift and nondestructive detecting method, offering a unique structural signature of analytes down to ultrasensitive levels. Herein, we present a novel SERS-based core-shell nanostructure with optimized silver shell thicknesses, capped with 2-mercaptoethylamine (2-MCE), to simultaneously detect multiple agrochemical residues in fruit samples. Compared to unmodified Au@AgNPs, the modified Au@Ag@2-MCENPs integrated with SERS exhibited improved sensitivity and stability, exhibiting a strong relationship between the SERS intensities and pesticide concentrations in the fruit samples, with LODs of 0.006 and 0.008 ppm for thiacloprid and 0.007 and 0.009 ppm for oxamyl in pear and apple fruit samples, respectively. Moreover, the method showed satisfactory recoveries ranging from 80 % to 106.5 % for thiacloprid and 81.8 % to 110.2 % for oxamyl in both fruit samples. Furthermore, this method presented rapid and simultaneous detection capabilities, significantly reducing analysis time compared to traditional methods, making it suitable for detecting other toxic chemical residues in agricultural products.
The objective of this study was to improve product quality of dehydrated fruits (apple, pear, papaya, mango) using combined drying techniques. This involved investigation of bioactivity, colour, and sensory assessment on colour of the dried products as well as the retention of the bio-active ingredients. The attributes of quality were compared in regard to the quality of dehydrated samples obtained from continuous heat pump (HP) drying technique. It was found that for apple, pear and mango the total colour change (ΔE) of samples dried using continuous heat pump (HP) or heat pump vacuum-microwave (HP/VM) methods was lower than of samples dried by other combined methods. However, for papaya, the lowest colour change exhibited by samples dried using hot air-cold air (HHC) method and the highest colour change was found for heat pump (HP) dehydrated samples. Sensory evaluation revealed that dehydrated pear with higher total colour change (ΔE) is more desirable because of its golden yellow appearance. In most cases the highest phenol content was found from fruits dried by HP/VM method. Judging from the quality findings on two important areas namely colour and bioactivity, it was found that combined drying method consisted of HP pre-drying followed by VM finish drying gave the best results for most dehydrated fruits studied in this work as the fruits contain first group of polyphenol compounds, which preferably requires low temperature followed by rapid drying strategy.
Pyrus pashia Buch.-Ham. ex D. Don. has been used conventionally by many communities in the Himalayan region for the management of gastrointestinal, respiratory, and vascular complications. Set against this background, this study was carried out to justify the scientific basis to validate folkloric uses of fruits of Pyrus pashia Buch.-Ham. ex D. Don. (Pp.Cr) in traditional systems of medicine.