PHYSICO-CHEMICAL PROPERTIES AND ANTIOXIDANT ACTIVITIES OF RHODOMYTUS TOMENTOSA SYRUP

Antioxidants are natural compounds found in many fruits, as well as in Rhodomyrtus tomentosa. The research, Rhodomyrtus tomentosa will be processed in form of syrup. The results of the organoleptic test of syrup ranged from like to very like by panelists. Determine the physical and chemical properties on syrup Rhodomyrtus tomentosa were acidity value is 4,41, total acid is 0,003%, total dissolved solids 23,74oBrix and sugar level of syrup is 21%. The results of Vitamin C content analysis of 1.25 mg / 100 g. The syrup contains Fe 0.525 mg / L and Cu 0.220 mg / L. In the Rhodomyrtus tomentosa syrup there is no lead (Pb), cadmium (Cd), Mercuri (Hg), Arsenic (As) and Stanum (Sn) metal. The content of antioxidant activity sirup is 10.31 %.


INTRODUCTION
Rhodomyrtus tomentosa is wild plants that grow in shrubs. Rhodomyrtus tomentosa is one of Indonesia's biodiversity. Rhodo-myrtus tomentosa fruits are dark purple, the taste of the fruits is sweet.
The result of organoleptic test showed that the leaves are green with a sense of fast and bitter, stems brown greenish, the roots are brown black rather red and purplish pink flowers with a distinctive smell and bitter taste. Blackish purple fruit after cooking, distinctive smell and taste sweet (Sutomo, 2010).
Active substances in fruit Rhodomyrtus tomentosa are flavonoids and saponins which are the polar compounds. According to Wong (2008) the type of flavonoids in Rhodomyrtus tomentosa is quercetin.
The result of its extract with ethyl acetate is a betulinic acid. 70% methanol extracts of leaves, stems and Rhodomyrtus tomentosa's flowers can kill bacteria S. aureus S. cerevisiae and F. oxysporum (Grosvenor, . Rhodomyrtus tomentosa fruits used to lower trigliseride concentration level wistar strain male (Noorrafiqi, 2013 were no clinical signs of general weakness in animals. This suggests that Rhodomyrtus tomentosa are safely consumed even at the highest doses 2000 mg / kg (Sunilson et al, 2009). So that needs followup research. The aim of the research is to make a safe and healthy drink of Rhodomyrtus tomentosa syrup. This syrup were determined by antioxidant activity, physical and chemical propertiesl content vitamin C, Fe and other metals

RESEARCH DESIGN
Research has second steps: First steps to known organoleptic assessment. Selected one of the most preferred syrup by panelists to be Ready-to-Eat product. Second step to know the physical and chemical properties, antioxidant activity, the metal content and Vitamin C in the syrup,

Making of Rhodomyrtus tomentosa syrup
The study design was experiment with 3 treatment. The data obtained were analyzed using analysis of variance and Duncan's New Multiple range test (DNMRT) at 5%. The treatment in this study: (A). Fruits is cutted and boiled and added sugar 55%, (B)Fruits is cutted, boiled and crushed then added sugar 55%, (C). Water is boiled and added fruits then fruits is cutted added sugar 55%.
After that all the syrups were filtered and stored in sterile bottles. Sensory assesment that includes color, aroma, consistenscy and taste. The most preferred hedonic test results, followed by testing in the laboratory.
Determine the physical and chemical properties on Rhodomyrtus tomentosa product were a total acid, pH, vitamin C, Total Dissolved Solids (TPT), Standard procedure for the chemical quality of pH and acid total were AOAC (1995)

Antioxidant activity with DPPH
The calibration curve was prepared by dissolving 5 mg DPPH in methanol in a 50 ml measuring flask. Then diluted to 5 ppm, 10ppm, 15ppm, 20ppm and 25 ppm concentrations. The absorbance was measured by a UV Vis spectrophotometer at 516 nm wavelength.
For the determination of antioxidant activity of syrup. Taken 1 ml of syrup put into a 100 ml measuring flask and added methanol to the limit. pipeted 0.2 ml sample and added 3.8 ml DPPH solution 20 ppm. Left for 30 minutes in a dark room at room temperature. measured absorbance at 516 nm. Blanks are made same procedure was methanol.

Vitamin C analysis
Content of vitamin C syrup measured by UV Vis spectrophotometer. The measurement begins with the determination of the maximum absorption of vitamin C. Maximum absorption was obtained at 262 nm wavelength. Linear equation of standard curve of vitamin C is y = 0,269 + 0,0433 X. R 2 =0,991 (Fig.1). Content of vitamin C syrup is 1,25 mg/100 g. The content of vitamin C syrup is smaller than that its fruit. According research of Lai (2014) content of vitamin C rhodomyrtus tomentosa 3,746 fruit per 100 g fruit. High-temperature cooking process causes the loss of vitamin C 0.0967 + 0.02382 X (Fig.2). Antioxidant actvity of Rodhomyrtus tomentosa syrup is 10,3148 %.

Content of Fe Syrup
Fe content of syrup rhodomyrtus tomentosa 0,525 mg / L. After has been processed into syrup Fe content is decreased. According to Lai (2014) content of Fe of Rhodomyrtus tomentosa for 4.2 mg/100 g. After has been boiled Fe content on the rhodomyrtud tomentosa syrup will be reduced.

The physical and chemical properties
Sugar content of syrup of Rhodomyrtus tomentosa is 21 %. The result of acidity of syrup is 0,003 % and pH 4,41. Total Dissolved solids 23,74 o Brix. When sugar is added with high concentrations cause reduced food activity water (Aw) and inhibited the growth of microorganisms.
According to the results of all metals tested, suitable to SNI standards. Cu was undetected in the standard to be considered. So this syrup is safe to drink.

Organoleptic Assesment
Organoleptic assessment is one important factor to determine degree of preference for a food product. A level assessment of product made, using hedonic scale of 1 to 6, meaning that 1=dislike, 2=somewhat like, 3 = neutral, 4=rather like, 5=likes, 6=very like. In general, the panelist liked almost all the rhodomyrtus tomentosa syrup. The most preferred syrup is B type. The taste of syrup is sweet, the aroma like honey and fruity (Fig.3).