Study On The Nutritive Components, Bioactive Phenols Compounds And Drying Processing Of The Loquat Flower

Loquat (Eriobotrya japonica Lindl.) is an evergreen fruit produced in subtropical region. About 70% of the world loquat is produced in China, which provided a large quantity of loquat flowers. The loquat flower has abundant bioactive compounds, such as flavonoid, carotenoid, phenols etc. In this study, basic nutritive components and bioactive phenols compounds were evaluated, identified and quantified in loquat flower (Ninghai white loquat and Ninghai red loquat flower) of different growth stage. Moreover, in order to get the best drying method for Ninghai white loquat flower, folin-phenol method, color difference analysis, sensory evaluation and GC-MS were used to evaluate the overall quality of loquat flower soup. The main results were as followings.1. It was found that the two varieties showed the similar results. The moisture and fat contents in the flower of Ninghai white loquat and Ninghai red loquat showed a small increase followed by an decrease during the growth stage, with the highest content 68.09% and 67.27% in middle growth stage. The ash content ranged between 2.9% and 5.2%, a decrease followed by an increase. Protein content showed no stable sigh and the content ranged between 6.8% and 10.1%. The total amino acid and mineral contents of the two varieties showed the similar results. The volatile components were obtained from the flower of Ninghai white loquat and detected by GC-MS.32 peaks compounds were identified, accounting for 95.03% of the total volatile components. The main compound was benzaldehyde (20.86%), followed by octacosane (14.94%).2. Phenols in Ninghai white loquat flower and Ninghai red loquat flower were identified and determined using a HPLC-PAD-MS method in the research. Six compounds were detected and four of them (chlorogenic acid, quercetin-3-o-glucoside, quercitrin and quercetin).were identified. The established methods showed good precision and accuracy. The recovery test was between 90.3% and 101.2%, and the CV of stability and inter-day repeatability were lower than 1%. The contents of the four compounds showed the same trend along with different growth stages in the flower of the two varieties. The chlorogenic acid and quercetin-3-o-glucoside contents in the flower of Ninghai white loquat and Ninghai red loquat showed a increase followed by an decrease during the growth stage. The quercitrin content showed a decrease followed by an increase, while total phenols content was on an increase with different growth stage. Compared to the flower of Ninghai red loquat, the flower of Ninghai white flower showed better quality, especially the contents of total phenols, chlorogenic acid and quercetin-3-o-glucoside. The content of total phenols reached 53.86 mg/g in late growth stage of Ninghai white loquat flower, with 46.29 mg/g in that of red loquat.3. In order to get the best drying method for loquat flower soup from different growth stage, folin-phenol method, color difference analysis, sensory evaluation method and GC-MS were used to evaluate the overall quality of loquat flower soup. Compared with early and late stage, the flower from the middle stage had better overall quality; in terms of the drying method, microwave drying, freeze drying and oven drying 100℃can better preserve the loquat flower quality.