Novel detection method to rapidly quantify toxic cucurbitacin in Lagenaria siceraria (bottle gourd).

Bottle gourd (Lagenaria siceraria) is widely used in India for its medicinal properties. Sometimes its consumption as a fruit or juice can lead to serious health issues due to the presence of toxic cucurbitacins (Cuc) like Cuc B at high concentration. In the present study, a molecularly imprinted polymer (MIP) based method was developed to quantify Cuc B in commercial bottle gourd juice. Cuc B quantification was also done in peel and pulp of fresh bottle gourd fruit. Developed MIP was superior to NIP (non-imprinted polymer) in terms of equilibrium binding, solid-phase extraction, selectivity, and loading capacity of Cuc B. Scatchard plot analysis, adsorption kinetics, and surface area study further strengthen the fact that prepared imprinted polymer was better than NIP for Cuc extraction. TLC and high-resolution LC-MS based analysis revealed that MIP selectively extracts Cuc B from all the studied samples. It was further observed that gamma irradiation and ß-glucosidase treatment did not have any significant (p > 0.05) effect on Cuc concentration. The quantity of Cuc in 100 g of juice, peel, and pulp was 2.81 ± 0.26, 3.37 ± 0.31, and 2.39 ± 0.21 mg, respectively. Analytical method validation indicates that the MIP based method was highly linear, precise, and accurate to rapidly quantify toxic Cuc B in bottle gourd consequently assuring its quality. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05600-3.

Alcoholic extraction enables EPR analysis to characterize radiation-induced cellulosic signals in spices.

Different spices such as turmeric, oregano, and cinnamon were γ-irradiated at 1 and 10 kGy. The electron paramagnetic resonance (EPR) spectra of the nonirradiated samples were characterized by a single central signal (g = 2.006), the intensity of which was significantly enhanced upon irradiation. The EPR spectra of the irradiated spice samples were characterized by an additional triplet signal at g = 2.006 with a hyperfine coupling constant of 3 mT, associated with the cellulose radical. EPR analysis on various sample pretreatments in the irradiated spice samples demonstrated that the spectral features of the cellulose radical varied on the basis of the pretreatment protocol. Alcoholic extraction pretreatment produced considerable improvements of the EPR signals of the irradiated spice samples relative to the conventional oven and freeze-drying techniques. The alcoholic extraction process is therefore proposed as the most suitable sample pretreatment for unambiguous detection of irradiated spices by EPR spectroscopy.

An improved approach to identify irradiated spices using electronic nose, FTIR, and EPR spectroscopy.

Changes in cumin and chili powder from India resulting from electron-beam irradiation were investigated using 3 analytical methods: electronic nose (E-nose), Fourier transform infrared (FTIR) spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The spices had been exposed to 6 to 14 kGy doses recommended for microbial decontamination. E-nose measured a clear difference in flavor patterns of the irradiated spices in comparison with the nonirradiated samples. Principal component analysis further showed a dose-dependent variation. FTIR spectra of the samples showed strong absorption bands at 3425, 3007 to 2854, and 1746 cm(-1). However, both nonirradiated and irradiated spice samples had comparable patterns without any noteworthy changes in functional groups. EPR spectroscopy of the irradiated samples showed a radiation-specific triplet signal at g = 2.006 with a hyper-fine coupling constant of 3 mT confirming the results obtained with the E-nose technique. Thus, E-nose was found to be a potential tool to identify irradiated spices.

Cyanocobalamin solutions as potential dosimeters in low-dose food irradiations.

Potential of aqueous solutions of cyanocobalamin in gamma radiation dosimetry was investigated. The solutions are inexpensive, nontoxic and easy-to-prepare dosimeters, which could be useful for measuring gamma radiation doses in various applications, such as quarantine treatment of fruit or insect disinfestation of grains and pulses. The optical absorbance of cyanocobalamin solutions of the optimal concentration 0.08 mM decreases with increasing radiation dose. The reproducible dependence of the absorbance decrease on the dose can be described with a polynomial. Pre- and post-irradiation stability of the solution absorbance, as well as effects of the irradiation temperature and dose rate, were studied. The response is not significantly affected by storage of the irradiated dosimeters under ambient conditions for 20 days. The performance characteristics of this chemical dosimetry system suggest that it can be useful to measure doses in irradiations of food.

Application of EPR spectroscopy to identify irradiated Indian medicinal plant products.

UNLABELLED: A study of gamma-irradiated Indian medicinal plant products was carried out using electron paramagnetic resonance (EPR) spectroscopy. Improved approaches like high-power measurement, microwave saturation, and thermal behavior of the radicals were explored for detection of irradiation. Aswagandha (Withania somnifera), vairi (Salacia reticulata), amla (Emblica officinalis), haldi (Curcumin longa), and guduchi (Tinospora cordifolia) exhibited a weak singlet at g = 2.005 before irradiation. Aswagandha, immediately after radiation treatment, revealed a complex EPR spectrum characterized by EPR spectrum simulation technique as superposition of 3 paramagnetic centers. One group of signal with organic origin was carbohydrate and cellulose radical and the other was isotropic signal of inorganic origin (g⟂ =2.0044 and g|| = 1.9980). However, other products did not exhibit any radiation-specific signal after irradiation. Power saturation and thermal behavior techniques were not suitable for these products. However, amongst all the 3 approaches, high-power measurement of EPR spectra emerged as a suitable technique in identification of the irradiated aswagandha. PRACTICAL APPLICATION: Gamma-irradiation confirms hygienic quality and improves shelf life of food and other products. However, there is a lack of international consensus over considering this as a general application and different regulations are being enforced. EPR is one of the most promising techniques to identify irradiated foodstuffs for regulatory requirements but it has many limitations. Improved approaches based on the EPR technique explained in this study may be useful to identify irradiated products and become beneficial to food regulators and food irradiation enterprises to enhance confidence in irradiation technology.

EPR-TL correlation studies on Bi co-doped CaSO4:Dy phosphor.

CaSO(4):Dy, CaSO(4):(Dy, Bi) and CaSO(4):Bi phosphors were prepared through re-crystallization method. Thermoluminescence (TL) characteristics of these phosphor samples were investigated. The radiation induced radical ions formed in these phosphors were investigated using electron paramagnetic resonance (EPR) spectroscopy. The main signals observed in both CaSO(4):(Dy, Bi) and CaSO(4):Bi were identified as SO(4)(-) (II), SO(4)(-) (⊥) and SO(3)(-) (isotropic) with "g" values 2.023, 2.0089 and 2.004, respectively. In order to understand the TL mechanism, CaSO(4):(Dy, Bi) phosphor samples were annealed between 100 and 250 °C and their EPR spectra were studied. It was observed that EPR signal intensities reduce drastically in 250 °C annealed phosphor confirming the role of SO(4)(-) and SO(3)(-) types of defect centers in the dosimetric peak. The reduction in the TL sensitivity with increase in Bi(3+) co-dopant in the phosphor samples was correlated with quenching of TL by Bi(3+) ions rather than the reduction in the concentration of the above defect centers. An effort was also made to use the Bi(3+) co-doped CaSO(4):Dy phosphor for dosimetry of chilled or frozen food irradiation.

A new electron paramagnetic resonance method to identify irradiated soybean.

Low-dose gamma irradiation causes minimal changes in food matrix making identification of radiation-processed foods a challenging task. In the present study, soybean samples were irradiated with commercially permitted gamma radiation dose in the 0.25 to 1.0 kGy range for insect disinfestations of food. Immediately after irradiation electron paramagnetic resonance (EPR) spectrum of the skin part of soybean showed a triplet signal (g = 2.0046, hyperfine coupling constant hfcc = 3.0 mT) superimposed on naturally present singlet. These signals were characterized as cellulose and phenoxyl radicals using EPR spectrum simulation technique. Kernel part of the samples exhibited a short-lived, radiation-induced singlet of carbon-centered radical superimposed on naturally present sextet signal of Mn2+. A detailed study on relaxation and thermal behavior of induced radicals in skin part was carried out using EPR spectroscopy. These findings revealed that progressive saturation and thermal characteristics of the induced radicals may be the most suitable parameters to distinguish soybean subjected to radiation dose as low as 0.25 kGy from thermally treated and nonirradiated samples, even after a prolonged period of storage.

Identification of irradiated cashew nut by electron paramagnetic resonance spectroscopy.

Cashew nut samples were irradiated at gamma-radiation doses of 0.25, 0.5, 0.75, and 1 kGy, the permissible dose range for insect disinfestation of food commodities. A weak and short-lived triplet (g = 2.004 and hfcc = 30 G) along with an anisotropic signal (g perpendicular = 2.0069 and g parallel = 2.000) were produced immediately after irradiation. These signals were assigned to that of cellulose and CO 2 (-) radicals. However, the irradiated samples showed a dose-dependent increase of the central line (g = 2.0045 +/- 0.0002). The nature of the free radicals formed during conventional processing such as thermal treatment was investigated and showed an increase in intensity of the central line (g = 2.0045) similar to that of irradiation. Characteristics of the free radicals were studied by their relaxation and thermal behaviors. The present work explores the possibility to identify irradiated cashew nuts from nonirradiated ones by the thermal behaviors of the radicals beyond the period, when the characteristic electron paramagnetic resonance spectral lines of the cellulose free radicals have essentially disappeared. In addition, this study for the first time reports that relaxation behavior of the radicals could be a useful tool to distinguish between roasted and irradiated cashew nuts.