Development of rose and crabapple compound beverage

: A nutrient-richness rose-crabapple compound beverage was developed using edible rose and crabapple as raw material, and the processing technology of compound beverage was also investigated. Fresh rose petals were mixed with sugar at the mass ratio of 1:1, maturing 3 months at room temperature. Then a unique-flavor rose liquor was extracted from the mature rose-sugar mixture, whereas the flavor crabapple extracts were extracted from 20 grams of crabapple in one liter purified water. The compound beverage processing parameters were identified to ensure the optimum rose beverage processing formula by sensory evaluation and orthogonal test.


Introduction
Rose (rosa rugosa thumb), also known as thorn rose, is a perennial evergreen or deciduous shrub of rose genus in Rosaceae [1] , with thick branches, and full of thorns on the epidermis of the stem section [2] . Rose cultivation has been in China for thousands of years and used as a spice plant endemic to China, whose petals are widely used in beauty, cosmetics, food, tea, wine, drugs, etc. [3] According to the analysis of pharmacological components, roses contain a lot of essential components for human body, such as volatile oil, phenylethyl alcohol, esters, nerol, red pigment, carotene, wax and so on. Among them, flavonoid glycosides, anthocyanins, and β-carotene have certain health and nutrition effects.
Plum-leaf crab (Malus prunifolia (Willd.) Borkh) is a special local product of Lijiang in Yunnan Province, with functions of appetizing, diuretic and anti-inflammatory. Plum-leaf crabs have abundant nutrients and is rich in vitamins, with the highest content of β-carotene ; edible plum-leaf crabs can supplement the trace elements needed by human body to promote health. The amino acid composition of plum-leaf crabs has higher content of aspartic acid and proline. Proline has the function and effect of brain health and brain protection, enhancing the effect of cellular respiration, while aspartic acid has anti-fatigue effect on human body. Calcium, protein, fat and other compositions are also very plentiful. In addition, plum-leaf crabs are effective in lowering blood pressure, strengthening stomach and digestion, lowering blood fat, softening blood vessels, fighting cancer and resisting oxidation [4][5] .
In recent years, the area of edible rose cultivation in Yunnan province has increased year by year, and the processed products of rose flowers are less, mainly concentrated on rose flower cake, rose candy, rose sauce and so on. In this study, roses and plum-leaf crabs were used as the main raw materials to study the compound beverage of rose and plum-leaf crab, which provided some theoretical reference for the production of rose compound products.

Materials and Instruments
Roses (Dianhong) and plum-leaf crabs (dried fruit) sold in Lijiang City, Yunnan Province; Citric acid sold in Weifang Yingxuan Industrial Co., Ltd.; Sucrose and honey sold in the market; SC-DC-AS electronic balance bought from Nanjing Suce measurement Co., Ltd.; Handheld saccharometer-ATAGO PAL-2 purchased from Japan Atago; Stainless steel cookers; Induction cooker of Midea DS2105; Gauze sold in the market; Glass bottles sold in the market, etc.

Preparation of rose juice
Rose (flower petals) → pretreatment → addition of white sugar → mixture → sealing → fermentation → extraction → filtration → rose flower juice

Preparation of plum-leaf crab juice
Plum-leaf crab → cleaning → extraction → filtration → clarification for standby

Treatment of roses
Edible roses (Dianhong) were selected and the petals were removed. The rose petals were cleaned up with water and dried out. The petals and white sugar were mixed and curlated at the ratio of 1:1, until the roses and white sugar were completely mixed. When the mixture became aubergine, it was sealed and fermented for more than 3 months, and rose sugar was obtained.

Extraction of rose sugar
Moderate rose sugar was weighed, added with a certain amount of citric acid and 1L of water. And it was heated and stirred to make the rose sugar fully dissolved, filtered, made up to 1L, and then rose juice was got.

Extraction of plum-leaf crabs
The non-rotted dried plum-leaf crabs were selected and weighed 20g, added 1L of water, stirred and boiled for 30min, and filtered. The filtrate was taken and diluted to 1L, and plum-leaf crab juice was obtained.

Blending
200 mL of plum-leaf crab juice was added to 300 mL of rose juice, and the mixture was added honey, white granulated sugar, and citric acid, and then mixed and filtered.

Sterilization and filling
After the rose and plum-leaf crab compound beverage was filled, it was sterilized in boiling water for 20-30 minutes, taken out, and cooled to obtain the finished product.

Sensory evaluation of products
The evaluation group for sensory evaluation of the products consisted of 10 food students (5 males and 5 females) [15] , and they scored separately in three aspects of color, fragrance and taste, and appearance. Total score of 100 points was used to evaluate, removing the highest score and the lowest score, and taking the average score as the final sensory score. The sensory scoring criteria are shown in Table 1.

Single factor experimental design of rose juice
Under the conditions of 200mL rose juice, 8% white granulated sugar, and 0.10% citric acid, the amount of rose juice was adjusted to 150 mL, 200 mL, 250 mL, 300 mL, and 350 mL, respectively, to determine the effect of the amount of rose juice on the quality of the rose and plum-leaf crab compound beverage.

Single factor experimental design of plum-leaf crab juice
Under the conditions of 200mL plum-leaf crab juice, 8% white granulated sugar, and 0.10% citric acid, the amount of rose juice was adjusted to 150 mL, 200 mL, 250 mL, 300 mL, and 350 mL, respectively, to determine the effect of the amount of plum-leaf crab juice on the quality of the rose and plum-leaf crab compound beverage.

Single factor experimental design of white granulated sugar
Under the conditions of 300mL rose juice, 200mL plum-leaf crab juice, and 0.10% citric acid, the additive amount of white granulated sugar was adjusted to 5%, 6%, 7%, 8%, and 9%, respectively, to determine the effect of the additive amount of white granulated sugar on the quality of the rose and plum-leaf crab compound beverage.

Single factor experimental design of citric acid addition
Under the conditions of 300mL rose juice, 200mL plum-leaf crab juice, and 8% white granulated sugar, the additive amount of citric acid was adjusted to 0.0%, 0.05%, 0.10%, 0.15%, and 0.20%, respectively, to determine the effect of the additive amount of citric acid on the quality of the rose and plum-leaf crab compound beverage.

Product quality detection
The content of soluble solids was determined by hand-held refractometer; the total acid content was determined by titration method referred to GB/T 12456-2008 [16] ; For the microbial index, the total bacterial number was determined by the method in GB 4789. 2-2010 [17] , the coliform was measured by the method in GB 4789. 3-2010 [18] , and the pathogenic bacteria was measured by the method in GB 29921-2013 [19] . According to the results of sensory evaluation in Table 2, the sensory score increases gradually with the increase of the additive amount of rose juice, and the highest score is obtained when the addition of rose juice is 300mL, with the best effect and moderate fragrance of rose. When the addition exceeds 300mL, the fragrance of rose is too strong, and the bitterness is also increased, which affects the overall quality of the compound beverage. Table 3 Effect of the addition of plum-leaf crab juice on the quality of the beverage Addition of plum-leaf crab juice/mL Sensory score/points 1150mL  78  200mL  81  250mL  85  300mL  84  350mL  80 From the sensory evaluation results in Table 3, it can be seen that with the increase of the additive amount of plum-leaf crab juice, the sensory score is gradually increased. The highest score is obtained when the additive amount of plum-leaf crab juice is 250mL, with the best effect and moderate fragrance of rose and plum-leaf crab compound beverage. When the addition exceeds 250mL, the sour taste also increases, affecting the quality of the compound beverage, so 200mL, 250mL, and 300mL are introduced for orthogonal experiment. As can been seen from the results of sensory evaluation in Table 4, the highest score is obtained when the addition of white granulated sugar is 7%, with the best ratio of sweet and sour and the most harmonious taste of rose and plum-leaf crab compound beverage. When the addition amount exceeds 7%, the sweetness increases with poorer taste, so 6%, 7%, and 8% are introduced for orthogonal experiments. According to the results of sensory evaluation in Table 5, the highest score is obtained when the addition of citric acid is 0.10%, with the best ratio of sweet and sour and the most harmonious taste of rose and plum-leaf crab compound beverage. When the addition reaches 7% or more, the sweetness increases with poorer taste, so 0.05%, 0.1%, and 0.15% are introduced for orthogonal experiments.

Formula optimization of rose beverage
In the orthogonal experiment design at the level of L9 (3 4 ), four factors and three levels of experiments were carried out, and the orthogonal experiment results are presented in Table 7.

Conclusions
The optimal formula of the rose and plum-leaf crab compound beverage was obtained through the orthogonal experiment results: It was 300mL rose juice, 200mL plum-leaf crab juice, 8% of white granulated sugar, 0.10% of citric acid, 0.8% of honey, and 1g licorice. The rose and plum-leaf crab compound beverage produced according to this formula has a unique fragrance of rose, rich floral fragrance, and the color is clear and bright, with a refreshing taste.