Postharvest Ultrasound-Assisted Freeze-Thaw Pretreatment Improves the Drying Efficiency, Physicochemical Properties, and Macamide Biosynthesis of Maca (Lepidium meyenii).

A novel technique of ultrasound-assisted freeze-thaw pretreatment (UFP) was developed to improve the drying efficiency of maca and bioactive amide synthesis in maca. The optimal UFP conditions are ultrasonic processing 90 min at 30 °C with 6 freeze-thaw cycles. Samples with freeze-thaw pretreatment (FP), ultrasound pretreatment (UP), and UFP were prepared for further comparative study. A no pretreatment (NP) sample was included as a control. The results showed that UFP improved the drying efficiency of maca slices, showing the highest effective moisture diffusivity (1.75 × 10-9 m2 /s). This result was further supported by low-field nuclear magnetic resonance (LF-NMR) analysis and scanning electron microscopy (SEM). The rehydration capacity and protein content of maca slices were improved by UFP. More importantly, contents of bioactive macamides and their biosynthetic precursors were increased in 2.5- and 10-fold, respectively. In conclusion, UFP is an efficient technique to improve drying efficiency, physicochemical properties, and bioactive macamides of maca, which can be applied in the industrial manufacture of maca products.

[Protective effect of Liuweidihuang Pills against cellphone electromagnetic radiation-induced histomorphological abnormality, oxidative injury, and cell apoptosis in rat testes].

OBJECTIVE: To observe the effect of Liuweidihuang Pills in relieving cellphone electromagnetic radiation-induced histomorphological abnormality, oxidative injury, and cell apoptosis in the rat testis. METHODS: Thirty adult male SD rats were equally randomized into a normal, a radiated, and a Liuweidihuang group, the animals in the latter two groups exposed to electromagnetic radiation of 900 MHz cellphone frequency 4 hours a day for 18 days. Meanwhile, the rats in the Liuweidihuang group were treated with the suspension of Liuweidihuang Pills at 1 ml/100 g body weight and the other rats intragastrically with the equal volume of purified water. Then all the rats were killed for observation of testicular histomorphology by routine HE staining, measurement of testicular malondialdehyde (MDA) and glutathione (GSH) levels by colorimetry, and determination of the expressions of bax and bcl-2 proteins in the testis tissue by immunohistochemistry. RESULTS: Compared with the normal controls, the radiated rats showed obviously loose structure, reduced layers of spermatocytes, and cavitation in the seminiferous tubules. Significant increases were observed in the MDA level (P < 0.01) and bax expression (P < 0.01) but decreases in the GSH level (P < 0.01) and bcl-2 expression (P < 0.01) in the testis issue of the radiated rats. In comparison with the radiated rats, those of the Liuweidihuang group exhibited nearly normal testicular structure, significantly lower MDA level (P < 0.05), bax expression (P < 0.01), and bcl-2 expression (P < 0.01). CONCLUSION: Liuweidihuang Pills can improve cellphone electromagnetic radiation-induced histomorphological abnormality of the testis tissue and reduce its oxidative damage and cell apoptosis.

Identification of maca (Lepidium meyenii Walp.) and its adulterants by a DNA-barcoding approach based on the ITS sequence.

Maca (Lepidium meyenii) is an herbaceous plant that grows in high plateaus and has been used as both food and folk medicine for centuries because of its benefits to human health. In the present study, ITS (internal transcribed spacer) sequences of forty-three maca samples, collected from different regions or vendors, were amplified and analyzed. The ITS sequences of nineteen potential adulterants of maca were also collected and analyzed. The results indicated that the ITS sequence of maca was consistent in all samples and unique when compared with its adulterants. Therefore, this DNA-barcoding approach based on the ITS sequence can be used for the molecular identification of maca and its adulterants.