A New Processing Technique for Drying Fresh Flowers of Species in Camellia Sect.Theopsis

Ni Sui*  Ying Zhen  Han Qin  Wu Fan
Faculty of Life Science and Biotechnology, Ningbo University, Ningbo 315211, PR China

Plants of Theaceae including tea and camellias are very common and valuable in south China. In China, people have started to plant, produce and drink tea several thousand years ago. Tea and camellias are the homology plants in genus of Camellia, so camellias probably have the same components in leaves with tea. Some products made of camellias in Taiwan and Guangxi of China are used as one kind of food by local people.

Sect.Theopsis belongs to Theaceae and Camellia. They have tiny, dense and fragrant flowers. Most of them are evergreen bushes or small arbors. At present, investigation of Sect.Theopsis mostly focuses on features of their growth requirements and classification, but few was on their chemical components in petals and leaves. In this paper, a new technique for drying fresh flowers has been successfully developed for C.parvicuspidata, C.handelii, C.tsofui, C.buxifolia, C.fraterna, C.cuspidata var.grandifora, which may provide a way for storage for long period and is very useful to develop some new camellia products in fields of medicine, health and food.

1 Material and Method

1.1 Samples treatment

Flowers of C.parvicuspidata, C.handelii, C.tsofui, C.buxifolia C.fraterna, C.cuspidata var.grandifora have been collected inMarch to April, 2012, in Jinhua International Camellia Species Garden, Zhejiang Province, China. Prior to experiment, they will be cleaned using pure water and dried in room temperature under 15℃ for one day.

1.2 Instrument

Analytical balance: METTLER TOLEDO AM104; Air dry oven: Jiacheng DHG-9045.; Microwave:  GalanzP70D20P-TD(WO); Oven: Midea MT10AH-AA

1.3 Reagent

Pure water

1.4 Method

1.4.1 Pretreatment

Screening out half-opening flower samples by hand.

1.4.2 Blanching

Blanching is a most important process in processing tea, which influences the quality of tea.Sect. Theopsis belong to Theaceae, just like tea. So blanching treatment should be a key step when drying.

1.4.2.1 Microwave blanching

Weighting some amount of fresh flower samples. Set the microwave power as 800w, 600w, 500w, 400w and blanching time as 20s, 40s, 60s, 80s, 100s, 120s. Six kinds of fresh flowers were treated for one time.

1.4.2.2 Thermal blanching

Weighting some amount of fresh flowers samples. Set the temperature control as 80℃, 100℃, 120℃, 140℃ and blanching time as 30s, 60s, 90s, 120s, 150s, 180s. 6Six kinds of fresh flowers were treated for one time.

1.4.3 Drying

Better quality flowers were chosen for next step before drying.

1.4.3.1 Dry by microwave

Choose better quality samples in 1.4.1 and dry them under microwave at 100w. A part of them were observed and recorded every 10 min. All of them were dried until water content is less 10%.

1.4.3.2 Thermal drying

Choose better samples in good appearance in 1.4.1 and dry them under 60℃. A part of them were observed and recorded every 30 min. All of them were dried until water content is less 10%.

2 Results and analysis

2.1 Blanching results

2.1.1 Blanching by Microwave

Results in Table 1 showed that there was very significant drying effect from microwave treatment. Flowers in six samples turned from half-opening (HO) to full-opening (FO) when microwave power at 800w and blanching time lasting for 20s. and Color of treated flowers look like fresh flowers with best appearances. Color of flowers will be changed from white (W) to pale yellow (PY) when blanching time lasted for 40s. When blanching time lasted for 80s, color of flowers was changed to yellow (Y), with average appearances. Flowers were apparently wrinkled up at 100s treatment. At last, color of treated flowers were changed from pale yellow to deep yellow (DY) in 120s with the worst appearances. The samples’ color was changed to PY with the best appearance when power at 600w, and blanching time lasted for 60s. At treatment of 80s, flowers changed from HO to FO, and colors were not changed further. At 120s color of samples was shrinkled (S) with the worst appearance. 6 samples’ appearances were not changed further when microwave power was at 500w or 400w, in which shapes of flowers are still in FO. In 80s, color turned to PY, with the better appearances. But the high water contents the difficult drying. On basis of color variations of six samples in various treatments, we found that the best combinations of treatments is blanching at 600w microwave blanching 600w and lasting for 80s, producing best quality of flower appearance.

Table1: Effects of microwave treatment at various times

shape：full open(FO);half open (HO); shrinking(S); color：deep yellow(DY) ;yellow(Y) ;pale yellow(PY) ;white(W)

 2.1.2 Thermal blanching

Table 2 showed that there were no variations for shape of samples at different temperature treatment, but color significantly changed under treating. Under 80℃, 6 samples’ colors turned to PY at 90s. What’ worst, color was DY at 150s. So this temperature treatment is suitable to blanch. When blanching lasted for 90s under 100℃, the samples’ colors were changed to PY during whole treatment period, but quality of appearance is not satisfied to further processing in this treatment. We have got suitable appearance quality in the condition: under 120℃ and 90s. If time beyond 150s, samples were become DY. The samples' color were deepened at 60s and under 140℃, and kept deepened in 90s. At last, samples were burned brown beyond 180s with the worst appearance. We found that the best blanching treatment is blanching time of 120s and blanching temperature of 120℃, producing best quality of flower appearance.

Table 2:   Effects of heat treatments at various times

shape：full open(FO);half open (HO);shrinking(S); color：deep yellow(DY) ;yellow(Y) ;pale yellow(PY) ;white(W)

 2.2 Drying

By comparison of two blanching ways, it was determined that best quality was obtained under microwave treatment of 80s and 600W. So, we chose the blanched samples under this treatment condition to be dried.

2.2.1 microwave drying

 The Fig 1 and table 3 showed that weights of samples were stable when drying lasted for 15min under low power microwave, and color was PY, with the best appearance. If treatment time lasted beyond 25 min, colors and shapes of flowers were become worst soon; The color of CK changed to PY just for 5 min, and deepened for 10min, with the worst quality of appearance. It was very clearly concluded that the best treatment is at drying time of 20 min and under low power microwave.

2.2.2 Thermal drying

The Fig.1 and Table 3 showed that weights of samples were stable while drying time lasted for 120min under low temperature, and better quality of flower appearance was obtained. The samples were apparently shrinkled beyond 150min, and color was changed to yellow, and further drying for 180min resulted in the worst quality of flower appearance. Under drying for 30min, CK samples were become pale yellow, and to yellow for 90 min. If drying for 150 min in CK, its quality of flower appearance was terrible.

By comparions, we found best quality was obtained by using Thermal drying for 120 min under low temperature. Furthermore , thermal drying is better than microwave.

3 Conclusions

A new technique for drying fresh flowers of plants in Sect. Theopsis of Theaceae was first successfully developed in our project, and we obtained the optimum condition as below: picking → cleaning → microwave blanching at 600w for 80s → thermal drying for 120min  → storage of samples. The results showed that treated flowers have their original color and shape, thus produce great potential economic value. Right now, technique for drying flowers was developed only for saving samples for long time. We will determine nutrition such as tea polyphenols, soluble sugar, amino acid, vitamin and so on, in future, including indexes of food security.

Acknowledgments:

This work was supported by the International Cooperation Project of China (2011DFA30490), and Zhejiang Key Flower Breeding Program (2012C12909-6).

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 * This project was supported by Zhejiang Key Program for Breeding New Flower Varieties (No.2012C12909-6)
Author for correspondence: Professor in ornamentals and flowers, nbnisui@126.com