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In the present study, a novel electrochemical sensor for the direct detection of caffeine in the crude sample has been prepared by plasma-triggered polydimethylsiloxane (PDMS) deposition on the indium tin oxide electrodes supported with silica nanochannels. The deposited PDMS contains both the original hydrophobic and oxidized hydrophilic PDMS oligomers. Nanochannels modified with these two kinds of PDMS with opposite wettability only allow the passage of small amphiphilic molecules such as caffeine, while other molecules including hydrophilic, hydrophobic, and large ones were all rejected. With the excellent shielding properties, the modified nanochannel electrode exhibits excellent anti-interference and antifouling capability, which could be directly used for the detection of caffeine in real crude food such as tea, milk, coffee, and coke without sample pretreatments. Moreover, the modified electrode has good repeatability and stability. In contrast, severe interference was observed when conventional electrodes were used directly in these unprocessed samples. The linear ranges of caffeine were determined to be between 50 nmol/L and 700 μmol/L, with a limit of detection of 20 nmol/L. The developed sensor provides a very simple, rapid, and cost-effective way for the interference-free and fouling-free analysis of specific amphiphilic compounds and can be extended to a wide range of applications.

Recent studies presented preharvest ultraviolet C (UV-C) as an environmentally friendly approach for the management of horticultural crop diseases. The effect of this approach on quality preservation during postharvest storage has not yet been investigated. Strawberry fruit harvested from plants grown with supplemental UV-C were stored at room temperature for 72 h, and their postharvest shelf-life biochemical indicators were evaluated. The involvement of microRNAs (miRNAs) in the activation of UV-C-induced antioxidant systems was investigated. Preharvest UV-C contributed to the preservation of sugar and organic acid and reduced overall lipid peroxidation in strawberry fruit during storage. We found that miR159 and miR398 were downregulated by preharvest UV-C and that their respective targets were upregulated at the early stage of storage with enhancement of the activity of antioxidant enzymes. The initial burst of H

To study the effects of stigmasterol and β-sitosterol on high-fat Western diet (HFWD)-induced nonalcoholic fatty liver disease (NAFLD), lipidomic analyses were conducted in liver samples collected after 33 weeks of the treatment. Principal component analysis showed these phytosterols were effective in protecting against HFWD-induced NAFLD. Orthogonal projections to latent structures-discriminate analysis (OPLS-DA) and S-plots showed that triacylglycerols (TGs), phosphatidylcholines, cholesteryl esters, diacylglycerols, and free fatty acids (FFAs) were the major lipid species contributing to these discriminations. The alleviation of NAFLD is mainly associated with decreases in hepatic cholesterol, TGs with polyunsaturated fatty acids, and alterations of free hepatic FFA. In conclusion, phytosterols, at a dose comparable to that suggested for humans by the FDA for the reduction of plasma cholesterol levels, are shown to protect against NAFLD in this long-term (33-week) study.

Preharvest ultraviolet C (UV-C) irradiation is an innovative approach for increasing the bioactive phytochemical content of strawberries to increase the disease resistance and nutritional value. This study investigated the changes in individual flavonoids in strawberry developed with three different cumulative doses of preharvest UV-C treatment (low, 9.6 kJ m–2; middle, 15 kJ m–2; and high , 29.4 kJ m–2). Significant accumulation (p < 0.05) of phenolics (25–75% increase), namely, cyanidin 3-glucoside, pelargonidin 3-glucoside/rutinoside, glucoside and glucuronide of quercetin and kaempferol, and ellagic acid, was found in the fruit subjected to low and middle supplemental doses of UV-C radiation. The expression of the flavonoid pathway structural genes, i.e., FaCHS1, FaCHI, FaFHT, FaDFR, FaFLS, and FaFGT, was upregulated in the low- and middle-dose groups, while the early stage genes were not affected by the high dose. FaMYB1 was also relatively enhanced in the low- and middle-dose groups, while FaASR was...

The effects of exogenous nitro oxide (NO) on chilling resistance and the metabolism of polyamine, proline, and γ-aminobutyric acid of bamboo shoots were investigated. Bamboo shoots were dipped in 0.07 mM sodium nitroprusside (SNP) and stored at 1 °C for 56 days. During the storage, the development of chilling injury of SNP treated bamboo shoots was inhibited with decreased accumulation of malonaldehyde and electrical leakage. At the end of storage, the chilling injury incidence of treated bamboo shoots decreased by 37.9% while their malonaldehyde content and electrical leakage were 8.8% and 18.6% lower than that of the control, respectively. Interestingly, the endogenous NO, polyamines, γ-aminobutyric acid, and proline contents of treated bamboo shoot also significantly increased. Consistently, the metabolisms of these nitrogenous compounds were stimulated in treated bamboo shoots, according to their higher (20.2%-49.8%) related enzyme activities, including nitric oxide synthase, arginine decarboxylase, ornithine decarboxylase, glutamate decarboxylase, orn-δ-aminotransferase, and Δ1-pyrroline-5-carboxylate synthetase. The results indicated that the SNP treatment enhanced chilling tolerance of bamboo shoots, which might associate with the activated metabolism of polyamines, γ-aminobutyric acid, and proline. SNP treatment might be an alternative technology to avoid chill injury during cold storage of bamboo shoots.

The effect of exogenous nitric oxide (NO) on chilling injury to banana fruit was investigated. Banana fruit was treated with NO donor sodium nitroprusside of 0.05 mM at 20 °C for 10 min and then stored at 7 °C for up to 20 days. Banana fruit treated with NO sustained a lower chilling injury index and higher firmness and kept lower electrolyte leakage and malondialdehyde content than the control. Further investigation showed that NO treatment enhanced activities of guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase compared to the control. It also maintained higher ascorbic acid, reduced glutathione content, and total antioxidant capacity but reduced hydrogen peroxide and superoxide anion to lower levels compared to control fruit during storage. NO treatment significantly enhanced the accumulation of total phenolics and proline, which resulted from the increased activities of phenylalanine ammonia-lyase and Δ¹-pyrroline-5-carboxylate synthetase and decreased proline dehydrogenase activity. We proposed that the enhanced chilling tolerance induced by NO treatment may result from the reduction of oxidative stress and proline accumulation.