Evaluation on the fresh eating quality of tree peony flowers

Tree peony(Paeonia suffruticosa)is an ornamental and medicinal plant in China.The fresh eating of flower petals has gradually become a new idea for further development.This study analyzed the sensory indexes,nutritional indexes and antioxidant indexes of fresh flowers of five cultivars,namely,‘Fengdan’(P.ostia‘Fengdan’),‘Xiangyu’(P.suffruticosa‘Xiangyu’),‘Zhaofen’(P.suffruticosa‘Zhanfen’),‘Luoyanghong’(P.suffruticosa‘Luoyanghong’)and‘High Noon’(P.‘High Noon’),to provide a theoretical basis for eating fresh tree peony flowers.The aroma volatiles of petals mainly comprised terpenes,alcohols and alkanes.‘Luoyanghong’and‘High Noon’have brighter colors.The taste test showed that‘Luoyanghong’,‘High Noon’and‘Xiangyu’were the most palatable.‘High Noon’contained the highest soluble sugar content,‘Luoyanghong’contained the highest starch and vitamin C(VC)levels,and‘Zhaofen’contained the highest soluble protein content.The contents of bioactive compounds were the highest in‘Luoyanghong’,and superoxide dismutase(SOD)activity was the highest in‘Xiangyu’.The petals were rich in essential amino acids,with the highest amount in‘Xiangyu’.‘Luoyanghong’and‘High Noon’showed strong antioxidant capacity.Therefore,tree peony flowers have excellent sensory qualities,abundant nutrients and strong antioxidant activity and could be further developed as a food to be eaten fresh.The results showed that tree peony flowers had great edible potential.Flowers of red and yellow cultivars can be considered for fresh eating on the basis of the traditional consumption of white and pink tree peony flowers.

Flavonoid content and expression analysis of flavonoid biosynthetic genes in herbaceous peony(Paeonia lactiflora Pall.)with double colors

Herbaceous peony（Paeonia lactiflora Pall.） is a famous flower with medicinal values, and its flowers have a number of medicinal constituents, especially flavonoids. In this study, a P. lactiflora cultivar with double colors including white outer-petal and yellow inner-petal was used as the experimental materials to perform the qualitative and quantitative analysis of flavonoids by high-performance liquid chromatograph-electrospray ionization-mass spectrometry（HPLC-ESI-MSn） and investigate the expression patterns of flavonoid biosynthetic genes using real-time quantitative polymerase chain reaction（Q-PCR）. The results showed that the colors of both petals gradually weakened with flower development. Moreover, one main anthocyanin composition（peonidin 3,5-di-O-glucoside） and five main anthoxanthin compositions（kaempferol di-hexoside, kaempferol-3-O-malonylglucoside-7-O-glucoside, quercetin-3-O-galactoside, luteolin-7-O-glucoside and isorhamnetin-3-O-glucoside） were found in the both, differing significantly in their peak areas only. Total anthocyanin, anthoxanthin and flavonoid contents in white outer-petal and yellow inner-petal gradually decreased during flower development, and were consistently higher in white outer-petal. Furthermore, the expression patterns of nine structural genes in P. lactiflora flavonoid biosynthetic pathway showed that the expression levels of phenylalanine ammonialyase gene（Pl PAL）, chalcone synthase gene（PlC HS）, flavanone 3-hydroxylase gene（PlF 3H）, anthocyanidin synthase gene（PlA NS） and UDP-glucoside： flavonoid 5-O-glucosyltransferase gene（Pl F5GT） in two petals basically presented declined tendencies, and transcription levels of Pl PAL, Pl CHS, Pl ANS, Pl F3 GT and Pl F5 GT also tended to be higher in white outer-petal, which was correlated with their flavonoid contents. These results would lay a solid foundation for the exploration and utilization of flavonoid resources in P. lactiflora flowers.