Effect of Ammonium Molybdate on Nutritional Quality and Volatile Substances of Muskmelon‘Qianyu No. 6’

MA Xueqiang;GAO Zixing;WANG Junzheng;QU Feng;ZHANG Jiao;HU Xiaohui;College of Horticulture, Northwest A&F University/Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture and Rural Affairs/Shaanxi Provincial Facility Agriculture Engineering Technology Center;

‘Qianyu No.6'muskmelon;;Ammonium molybdate tetrahydrate;;Nutritional quality;;Volatile substances;;OAV;;PCA-TOPSIS

Molybdenum is one of the important trace elements for plant growth and formation of nutritional quality.To meethigh-quality production needs of melons, the matrix bag culture method was used to find the appropriate concentration of molybdenum fertilizer, the effect of ammonium molybdate tetrahydrate on the nutritional quality and volatile substances of melon fruit was discussed. The thin-skinned melon variety‘Qianyu No.6'was used as the material, three levels of ammonium molybdate tetrahydrate [(NH_4)_2MoO_4·4 H_2O] at 0,0.02 and 0.04 mg/L were set. Chemical methods and headspace solid-phase microextraction-gas chromatography-mass spectrometry were used to determine the nutrient quality and volatile components. The results showed that thecontent of soluble protein, soluble solids, nitrate and reducing sugar in the fruits first increased and then decreased with the increase of the concentration of ammonium molybdate. On the contrary, the content of titratable acid and ascorbic acid was positively correlated with the concentration of ammonium molybdate; the amount of ammonium molybdate had great influence on the aroma components and content of melon fruit; under treatment of 0.04 mg/L ammonium molybdate, the total content of 28 aroma components detected in the fruits was 447.89 μg/kg, and boththe detected aroma types and contents were lower than other treatments, but its detected esters accounted for 61.79%,which was higher than other treatments. At the same time, 0.04 mg/L treatment had the most of the aroma substances, which included 8 substances, namely ethyl butyrate, ethyl 2-methyl butyrate, butyl 2-methyl acetate, hexyl acetate, 1-octene-3-ol,(E, Z)-3,6-nonadien-1-ol,(Z)-6-nonen-1-ol and(Z)-6-nonenal, a total relative content was 49.26%,and it was higher than other treatments. In conclusion, the application of 0.04 mg/L ammonium molybdate tetrahydrate can effectively improve the nutrition and flavor quality of muskmelon fruit, and it can be used as the optimum concentration of molybdenum fertilizer for high-quality production of melon.