Browning difference analysis and select evaluation about the optimal plant seeds of Castanea henryi

Abstract：【Objective】Castanea henryi, a chestnut species belong to the Fagaceae, was one of the woody species of grain in China. Due to its good economic value and good fruit quality, C. henryi was high popularity in broad consumers. However, the browning phenomenon of C. henryi occurred frequently in the process of storage which directly affected the appearance, flavor, and lower quality of products. Thus it is especially important to study of the ability to resist browning in C. henryi. To explore anti-browning ability resources and get the C. henryi fruit processing plant type, we selected the optimal plant type from superior plants, which is suitable for deep processing of C. henryi.【Methods】Previous collected 96 excellent individuals branches of C. henryi from some regions of Hunan and Fujian, though the method of Crown-grafting in agricultural base in Rucheng, Hunan, which was cooperate with Central South Forestry University of Science and Technology in 2012, then we got 30 samples in2015. The experiment was carried out with a randomized block design. Taking 30 different superior plants' seeds of C. henryi as the test materials with boiling water bath after 20 minutes, we made it to be binary segmentation and comparative screening. We observed its browning phenomenon, and divided the browning phenomenon into six grade (level 0 was no browning, and keep original color and texture. Level 1 was mild browning, and section was slightly brown, and the brown area was 10%. Level 2 was moderate browning, and apparently occurred browning, but the original color and texture were still clearly visible, and browning area was 20%. Level 3 was severe browning, and the original color and quality of a material were hard to discern and ambiguous, and browning area was 30%. Level 4 was extreme browning, which was unable to identify initial color and texture, and browning area was 40%.Level 5 was the initial basic color disappeared, quality of a material to harden, and browning area was more than 50%) . Then we through the six grade to get the browning index, which reflected the degree of browning. Folin-phenol method was used to determine total phenol content. Xylene-extraction colorimetry was used to determine the levels of vitamin C. The data collected were processed using Microsoft Excel 2003. Using IBM SPSS Statistics 22 was aimed to the browning differences clustering analysis, and combined with the determination of the total phenolic content and the level of vitamin C, as well as its correlation.【Results】The results showed that the browning of 30 C. henryi was an universal phenomenon, which indicated C. henryi browning mechanism may be the same or similar, and there were some differences in the degree of browning. There existed individuals, which had strong resistance of browning, such as ZNL-1 and JZPYS-1, with the degree of browning index 0.067 and 0.083, respectively for 6.7% of the total of 30 samples. The browning was extremely serious, such as ZNL-4 and ZNL-13, from 7.2 to 9.7 times between the highest and lowest. In the study, the difference of total phenolic content was remarkable, and browning index was positively correlated with the content of total phenolic. ZNL-13 total phenol content was the highest to 229.65 mg·100 g^-1 in the seeds, and browning degree was the highest. However, ZNL-15 was the lowest only 27.91 mg·100 g^-1, relatively low total phenolic content such as ZNL-1, ZNL-8, ZNL-9, ZNL-34 and JZPYS-1. Overall, the level of vitamin C was relatively high and remarkable, and the highest was ZNL-11, which was more 2 times than the lowest one.【Conclusion】The browning of C. henryi were differences between 30 C. henryi, and there exsited strong resistance of browning resources of C. henryi, such as ZNL-1, ZNL-15 and JZPYS-1. In the study, the type of low degree of browning of C. henryi could be considered to apply in the C. henryi cross breeding and seed-breeding and products deep processing.