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We prepared a detoxified rapeseed protein isolate (RPI) by phytase/ethanol treatment based on alkaline extraction and acidic precipitation. Contents of protein, fat, ash, moisture, crude fiber, glucosinolates, phytic acid, and phenolics and color were determined. To evaluate the safety of detoxified RPI, five groups of C57 mice (detoxified RPI [10 and 20 g kg -1 ]; commercial soybean protein isolate (SPI) [10 g kg -1 ]; non-detoxified RPI [10 g kg -1 ]; control) were used in the acute-toxicity test. Bodyweight and pathology parameters were recorded at different time points, followed by macroscopic examination, organ-weight measurement and microstructure examination. After pretreatment of rapeseed meals with phytase (enzyme : substrate ratio, 1 : 5 mg g -1 ) for 1.5 h and two-time ethanol extraction for precipitated protein, the chemical characteristics in RPI were protein (88.26%), fat (0.57%), ash (2.72%), moisture (1.90%), crude fiber (0.77%), glucosinolates (0 μmol g -1 ), phytic acid (0.17%), phenolics (0.36%) and whiteness (73.38). Treatment resulted in significant removal of anti-nutritional factors (ANFs) and increased whiteness in detoxified RPI compared with non-detoxified RPI, and lower than in cruciferin-rich canola protein isolate (Puratein®). Experimental-related effects on bodyweight, clinical observations, or clinicopathology, in mice treated with detoxified RPI were not observed except for a decreased thyroid gland/parathyroid gland index in mice treated with non-detoxified RPI. Furthermore, the no-observed-effect level (NOEL) was 10 g kg -1 of detoxified RPI, whereas the no-observed-adverse-effect-level (NOAEL) was the highest fed level of 20 g kg -1 of detoxified RPI. Overall, detoxified RPI prepared by the combined treatment of phytase and ethanol was considered safe under the conditions tested, in which the contents of the main ANFs were reduced significantly.

Zinc oxide nanoparticles (ZnO NPs) are widely used to manufacture textile fibers, synthetic rubber, and paint. However, crop yields and quality are threatened by the increased use of metallic NPs in industry, which has resulted in their accumulation in agricultural land. Many studies have shown that plants defend against biotic and abiotic stresses through the activities of metabolites and hormones. However, whether glucosinolates (GSs) are involved in plant responses to ZnO NP-related stress remains unknown. In this study, wild-type (WT) and GS mutant (myb28/29 and cyp79B2/B3) Arabidopsis plants were subjected to ZnO NP stress to address this question. Our results showed that exposure to ZnO NPs promoted GS accumulation and induced the relative messenger RNA (mRNA) expression levels of GS biosynthesis-related genes. Moreover, ZnO NP treatment adversely affected root length, the number of lateral roots, chlorophyll contents, and plant biomass. Importantly, our results showed that root growth, chlorophyll contents, and plant biomass were all decreased in the GS mutants compared with those in WT plants. Overall, our results showed that WT plants tolerated ZnO NP-induced stress more efficiently than the GS mutants, suggesting that GSs are involved in plant resistance to ZnO NP-induced toxicity.